| Index: third_party/libpng/png.c
|
| diff --git a/third_party/lpng_v163/png.c b/third_party/libpng/png.c
|
| similarity index 85%
|
| rename from third_party/lpng_v163/png.c
|
| rename to third_party/libpng/png.c
|
| index 93c675b085a78efec00c8e2419c82f6e78a5213d..c183e3f8faf8f38cee95d8fb7b7edc9c2297cb64 100644
|
| --- a/third_party/lpng_v163/png.c
|
| +++ b/third_party/libpng/png.c
|
| @@ -1,4297 +1,4498 @@
|
| -/* png.c - location for general purpose libpng functions
|
| - *
|
| - * Last changed in libpng 1.6.2 [April 25, 2013]
|
| - * Copyright (c) 1998-2013 Glenn Randers-Pehrson
|
| - * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
|
| - * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
|
| - *
|
| - * This code is released under the libpng license.
|
| - * For conditions of distribution and use, see the disclaimer
|
| - * and license in png.h
|
| - */
|
| -
|
| -#include "pngpriv.h"
|
| -
|
| -/* Generate a compiler error if there is an old png.h in the search path. */
|
| -typedef png_libpng_version_1_6_3 Your_png_h_is_not_version_1_6_3;
|
| -
|
| -/* Tells libpng that we have already handled the first "num_bytes" bytes
|
| - * of the PNG file signature. If the PNG data is embedded into another
|
| - * stream we can set num_bytes = 8 so that libpng will not attempt to read
|
| - * or write any of the magic bytes before it starts on the IHDR.
|
| - */
|
| -
|
| -#ifdef PNG_READ_SUPPORTED
|
| -void PNGAPI
|
| -png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
|
| -{
|
| - png_debug(1, "in png_set_sig_bytes");
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - if (num_bytes > 8)
|
| - png_error(png_ptr, "Too many bytes for PNG signature");
|
| -
|
| - png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
|
| -}
|
| -
|
| -/* Checks whether the supplied bytes match the PNG signature. We allow
|
| - * checking less than the full 8-byte signature so that those apps that
|
| - * already read the first few bytes of a file to determine the file type
|
| - * can simply check the remaining bytes for extra assurance. Returns
|
| - * an integer less than, equal to, or greater than zero if sig is found,
|
| - * respectively, to be less than, to match, or be greater than the correct
|
| - * PNG signature (this is the same behavior as strcmp, memcmp, etc).
|
| - */
|
| -int PNGAPI
|
| -png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
|
| -{
|
| - png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
|
| -
|
| - if (num_to_check > 8)
|
| - num_to_check = 8;
|
| -
|
| - else if (num_to_check < 1)
|
| - return (-1);
|
| -
|
| - if (start > 7)
|
| - return (-1);
|
| -
|
| - if (start + num_to_check > 8)
|
| - num_to_check = 8 - start;
|
| -
|
| - return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check)));
|
| -}
|
| -
|
| -#endif /* PNG_READ_SUPPORTED */
|
| -
|
| -#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
|
| -/* Function to allocate memory for zlib */
|
| -PNG_FUNCTION(voidpf /* PRIVATE */,
|
| -png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
|
| -{
|
| - png_alloc_size_t num_bytes = size;
|
| -
|
| - if (png_ptr == NULL)
|
| - return NULL;
|
| -
|
| - if (items >= (~(png_alloc_size_t)0)/size)
|
| - {
|
| - png_warning (png_voidcast(png_structrp, png_ptr),
|
| - "Potential overflow in png_zalloc()");
|
| - return NULL;
|
| - }
|
| -
|
| - num_bytes *= items;
|
| - return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
|
| -}
|
| -
|
| -/* Function to free memory for zlib */
|
| -void /* PRIVATE */
|
| -png_zfree(voidpf png_ptr, voidpf ptr)
|
| -{
|
| - png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
|
| -}
|
| -
|
| -/* Reset the CRC variable to 32 bits of 1's. Care must be taken
|
| - * in case CRC is > 32 bits to leave the top bits 0.
|
| - */
|
| -void /* PRIVATE */
|
| -png_reset_crc(png_structrp png_ptr)
|
| -{
|
| - /* The cast is safe because the crc is a 32 bit value. */
|
| - png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
|
| -}
|
| -
|
| -/* Calculate the CRC over a section of data. We can only pass as
|
| - * much data to this routine as the largest single buffer size. We
|
| - * also check that this data will actually be used before going to the
|
| - * trouble of calculating it.
|
| - */
|
| -void /* PRIVATE */
|
| -png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
|
| -{
|
| - int need_crc = 1;
|
| -
|
| - if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))
|
| - {
|
| - if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
|
| - (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
|
| - need_crc = 0;
|
| - }
|
| -
|
| - else /* critical */
|
| - {
|
| - if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
|
| - need_crc = 0;
|
| - }
|
| -
|
| - /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
|
| - * systems it is a 64 bit value. crc32, however, returns 32 bits so the
|
| - * following cast is safe. 'uInt' may be no more than 16 bits, so it is
|
| - * necessary to perform a loop here.
|
| - */
|
| - if (need_crc && length > 0)
|
| - {
|
| - uLong crc = png_ptr->crc; /* Should never issue a warning */
|
| -
|
| - do
|
| - {
|
| - uInt safe_length = (uInt)length;
|
| - if (safe_length == 0)
|
| - safe_length = (uInt)-1; /* evil, but safe */
|
| -
|
| - crc = crc32(crc, ptr, safe_length);
|
| -
|
| - /* The following should never issue compiler warnings; if they do the
|
| - * target system has characteristics that will probably violate other
|
| - * assumptions within the libpng code.
|
| - */
|
| - ptr += safe_length;
|
| - length -= safe_length;
|
| - }
|
| - while (length > 0);
|
| -
|
| - /* And the following is always safe because the crc is only 32 bits. */
|
| - png_ptr->crc = (png_uint_32)crc;
|
| - }
|
| -}
|
| -
|
| -/* Check a user supplied version number, called from both read and write
|
| - * functions that create a png_struct.
|
| - */
|
| -int
|
| -png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
|
| -{
|
| - if (user_png_ver)
|
| - {
|
| - int i = 0;
|
| -
|
| - do
|
| - {
|
| - if (user_png_ver[i] != png_libpng_ver[i])
|
| - png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
|
| - } while (png_libpng_ver[i++]);
|
| - }
|
| -
|
| - else
|
| - png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
|
| -
|
| - if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
|
| - {
|
| - /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
|
| - * we must recompile any applications that use any older library version.
|
| - * For versions after libpng 1.0, we will be compatible, so we need
|
| - * only check the first and third digits (note that when we reach version
|
| - * 1.10 we will need to check the fourth symbol, namely user_png_ver[3]).
|
| - */
|
| - if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
|
| - (user_png_ver[0] == '1' && (user_png_ver[2] != png_libpng_ver[2] ||
|
| - user_png_ver[3] != png_libpng_ver[3])) ||
|
| - (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
|
| - {
|
| -#ifdef PNG_WARNINGS_SUPPORTED
|
| - size_t pos = 0;
|
| - char m[128];
|
| -
|
| - pos = png_safecat(m, (sizeof m), pos,
|
| - "Application built with libpng-");
|
| - pos = png_safecat(m, (sizeof m), pos, user_png_ver);
|
| - pos = png_safecat(m, (sizeof m), pos, " but running with ");
|
| - pos = png_safecat(m, (sizeof m), pos, png_libpng_ver);
|
| -
|
| - png_warning(png_ptr, m);
|
| -#endif
|
| -
|
| -#ifdef PNG_ERROR_NUMBERS_SUPPORTED
|
| - png_ptr->flags = 0;
|
| -#endif
|
| -
|
| - return 0;
|
| - }
|
| - }
|
| -
|
| - /* Success return. */
|
| - return 1;
|
| -}
|
| -
|
| -/* Generic function to create a png_struct for either read or write - this
|
| - * contains the common initialization.
|
| - */
|
| -PNG_FUNCTION(png_structp /* PRIVATE */,
|
| -png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
|
| - png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
|
| - png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
|
| -{
|
| - png_struct create_struct;
|
| -# ifdef PNG_SETJMP_SUPPORTED
|
| - jmp_buf create_jmp_buf;
|
| -# endif
|
| -
|
| - /* This temporary stack-allocated structure is used to provide a place to
|
| - * build enough context to allow the user provided memory allocator (if any)
|
| - * to be called.
|
| - */
|
| - memset(&create_struct, 0, (sizeof create_struct));
|
| -
|
| - /* Added at libpng-1.2.6 */
|
| -# ifdef PNG_USER_LIMITS_SUPPORTED
|
| - create_struct.user_width_max = PNG_USER_WIDTH_MAX;
|
| - create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
|
| -
|
| -# ifdef PNG_USER_CHUNK_CACHE_MAX
|
| - /* Added at libpng-1.2.43 and 1.4.0 */
|
| - create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
|
| -# endif
|
| -
|
| -# ifdef PNG_USER_CHUNK_MALLOC_MAX
|
| - /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
|
| - * in png_struct regardless.
|
| - */
|
| - create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
|
| -# endif
|
| -# endif
|
| -
|
| - /* The following two API calls simply set fields in png_struct, so it is safe
|
| - * to do them now even though error handling is not yet set up.
|
| - */
|
| -# ifdef PNG_USER_MEM_SUPPORTED
|
| - png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
|
| -# endif
|
| -
|
| - /* (*error_fn) can return control to the caller after the error_ptr is set,
|
| - * this will result in a memory leak unless the error_fn does something
|
| - * extremely sophisticated. The design lacks merit but is implicit in the
|
| - * API.
|
| - */
|
| - png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
|
| -
|
| -# ifdef PNG_SETJMP_SUPPORTED
|
| - if (!setjmp(create_jmp_buf))
|
| - {
|
| - /* Temporarily fake out the longjmp information until we have
|
| - * successfully completed this function. This only works if we have
|
| - * setjmp() support compiled in, but it is safe - this stuff should
|
| - * never happen.
|
| - */
|
| - create_struct.jmp_buf_ptr = &create_jmp_buf;
|
| - create_struct.jmp_buf_size = 0; /*stack allocation*/
|
| - create_struct.longjmp_fn = longjmp;
|
| -# else
|
| - {
|
| -# endif
|
| - /* Call the general version checker (shared with read and write code):
|
| - */
|
| - if (png_user_version_check(&create_struct, user_png_ver))
|
| - {
|
| - png_structrp png_ptr = png_voidcast(png_structrp,
|
| - png_malloc_warn(&create_struct, (sizeof *png_ptr)));
|
| -
|
| - if (png_ptr != NULL)
|
| - {
|
| - /* png_ptr->zstream holds a back-pointer to the png_struct, so
|
| - * this can only be done now:
|
| - */
|
| - create_struct.zstream.zalloc = png_zalloc;
|
| - create_struct.zstream.zfree = png_zfree;
|
| - create_struct.zstream.opaque = png_ptr;
|
| -
|
| -# ifdef PNG_SETJMP_SUPPORTED
|
| - /* Eliminate the local error handling: */
|
| - create_struct.jmp_buf_ptr = NULL;
|
| - create_struct.jmp_buf_size = 0;
|
| - create_struct.longjmp_fn = 0;
|
| -# endif
|
| -
|
| - *png_ptr = create_struct;
|
| -
|
| - /* This is the successful return point */
|
| - return png_ptr;
|
| - }
|
| - }
|
| - }
|
| -
|
| - /* A longjmp because of a bug in the application storage allocator or a
|
| - * simple failure to allocate the png_struct.
|
| - */
|
| - return NULL;
|
| -}
|
| -
|
| -/* Allocate the memory for an info_struct for the application. */
|
| -PNG_FUNCTION(png_infop,PNGAPI
|
| -png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
|
| -{
|
| - png_inforp info_ptr;
|
| -
|
| - png_debug(1, "in png_create_info_struct");
|
| -
|
| - if (png_ptr == NULL)
|
| - return NULL;
|
| -
|
| - /* Use the internal API that does not (or at least should not) error out, so
|
| - * that this call always returns ok. The application typically sets up the
|
| - * error handling *after* creating the info_struct because this is the way it
|
| - * has always been done in 'example.c'.
|
| - */
|
| - info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
|
| - (sizeof *info_ptr)));
|
| -
|
| - if (info_ptr != NULL)
|
| - memset(info_ptr, 0, (sizeof *info_ptr));
|
| -
|
| - return info_ptr;
|
| -}
|
| -
|
| -/* This function frees the memory associated with a single info struct.
|
| - * Normally, one would use either png_destroy_read_struct() or
|
| - * png_destroy_write_struct() to free an info struct, but this may be
|
| - * useful for some applications. From libpng 1.6.0 this function is also used
|
| - * internally to implement the png_info release part of the 'struct' destroy
|
| - * APIs. This ensures that all possible approaches free the same data (all of
|
| - * it).
|
| - */
|
| -void PNGAPI
|
| -png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
|
| -{
|
| - png_inforp info_ptr = NULL;
|
| -
|
| - png_debug(1, "in png_destroy_info_struct");
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - if (info_ptr_ptr != NULL)
|
| - info_ptr = *info_ptr_ptr;
|
| -
|
| - if (info_ptr != NULL)
|
| - {
|
| - /* Do this first in case of an error below; if the app implements its own
|
| - * memory management this can lead to png_free calling png_error, which
|
| - * will abort this routine and return control to the app error handler.
|
| - * An infinite loop may result if it then tries to free the same info
|
| - * ptr.
|
| - */
|
| - *info_ptr_ptr = NULL;
|
| -
|
| - png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
|
| - memset(info_ptr, 0, (sizeof *info_ptr));
|
| - png_free(png_ptr, info_ptr);
|
| - }
|
| -}
|
| -
|
| -/* Initialize the info structure. This is now an internal function (0.89)
|
| - * and applications using it are urged to use png_create_info_struct()
|
| - * instead. Use deprecated in 1.6.0, internal use removed (used internally it
|
| - * is just a memset).
|
| - *
|
| - * NOTE: it is almost inconceivable that this API is used because it bypasses
|
| - * the user-memory mechanism and the user error handling/warning mechanisms in
|
| - * those cases where it does anything other than a memset.
|
| - */
|
| -PNG_FUNCTION(void,PNGAPI
|
| -png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size),
|
| - PNG_DEPRECATED)
|
| -{
|
| - png_inforp info_ptr = *ptr_ptr;
|
| -
|
| - png_debug(1, "in png_info_init_3");
|
| -
|
| - if (info_ptr == NULL)
|
| - return;
|
| -
|
| - if ((sizeof (png_info)) > png_info_struct_size)
|
| - {
|
| - *ptr_ptr = NULL;
|
| - /* The following line is why this API should not be used: */
|
| - free(info_ptr);
|
| - info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
|
| - (sizeof *info_ptr)));
|
| - *ptr_ptr = info_ptr;
|
| - }
|
| -
|
| - /* Set everything to 0 */
|
| - memset(info_ptr, 0, (sizeof *info_ptr));
|
| -}
|
| -
|
| -/* The following API is not called internally */
|
| -void PNGAPI
|
| -png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
|
| - int freer, png_uint_32 mask)
|
| -{
|
| - png_debug(1, "in png_data_freer");
|
| -
|
| - if (png_ptr == NULL || info_ptr == NULL)
|
| - return;
|
| -
|
| - if (freer == PNG_DESTROY_WILL_FREE_DATA)
|
| - info_ptr->free_me |= mask;
|
| -
|
| - else if (freer == PNG_USER_WILL_FREE_DATA)
|
| - info_ptr->free_me &= ~mask;
|
| -
|
| - else
|
| - png_error(png_ptr, "Unknown freer parameter in png_data_freer");
|
| -}
|
| -
|
| -void PNGAPI
|
| -png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
|
| - int num)
|
| -{
|
| - png_debug(1, "in png_free_data");
|
| -
|
| - if (png_ptr == NULL || info_ptr == NULL)
|
| - return;
|
| -
|
| -#ifdef PNG_TEXT_SUPPORTED
|
| - /* Free text item num or (if num == -1) all text items */
|
| - if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
|
| - {
|
| - if (num != -1)
|
| - {
|
| - if (info_ptr->text && info_ptr->text[num].key)
|
| - {
|
| - png_free(png_ptr, info_ptr->text[num].key);
|
| - info_ptr->text[num].key = NULL;
|
| - }
|
| - }
|
| -
|
| - else
|
| - {
|
| - int i;
|
| - for (i = 0; i < info_ptr->num_text; i++)
|
| - png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
|
| - png_free(png_ptr, info_ptr->text);
|
| - info_ptr->text = NULL;
|
| - info_ptr->num_text=0;
|
| - }
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_tRNS_SUPPORTED
|
| - /* Free any tRNS entry */
|
| - if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
|
| - {
|
| - png_free(png_ptr, info_ptr->trans_alpha);
|
| - info_ptr->trans_alpha = NULL;
|
| - info_ptr->valid &= ~PNG_INFO_tRNS;
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_sCAL_SUPPORTED
|
| - /* Free any sCAL entry */
|
| - if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
|
| - {
|
| - png_free(png_ptr, info_ptr->scal_s_width);
|
| - png_free(png_ptr, info_ptr->scal_s_height);
|
| - info_ptr->scal_s_width = NULL;
|
| - info_ptr->scal_s_height = NULL;
|
| - info_ptr->valid &= ~PNG_INFO_sCAL;
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_pCAL_SUPPORTED
|
| - /* Free any pCAL entry */
|
| - if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
|
| - {
|
| - png_free(png_ptr, info_ptr->pcal_purpose);
|
| - png_free(png_ptr, info_ptr->pcal_units);
|
| - info_ptr->pcal_purpose = NULL;
|
| - info_ptr->pcal_units = NULL;
|
| - if (info_ptr->pcal_params != NULL)
|
| - {
|
| - unsigned int i;
|
| - for (i = 0; i < info_ptr->pcal_nparams; i++)
|
| - {
|
| - png_free(png_ptr, info_ptr->pcal_params[i]);
|
| - info_ptr->pcal_params[i] = NULL;
|
| - }
|
| - png_free(png_ptr, info_ptr->pcal_params);
|
| - info_ptr->pcal_params = NULL;
|
| - }
|
| - info_ptr->valid &= ~PNG_INFO_pCAL;
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_iCCP_SUPPORTED
|
| - /* Free any profile entry */
|
| - if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
|
| - {
|
| - png_free(png_ptr, info_ptr->iccp_name);
|
| - png_free(png_ptr, info_ptr->iccp_profile);
|
| - info_ptr->iccp_name = NULL;
|
| - info_ptr->iccp_profile = NULL;
|
| - info_ptr->valid &= ~PNG_INFO_iCCP;
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_sPLT_SUPPORTED
|
| - /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
|
| - if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
|
| - {
|
| - if (num != -1)
|
| - {
|
| - if (info_ptr->splt_palettes)
|
| - {
|
| - png_free(png_ptr, info_ptr->splt_palettes[num].name);
|
| - png_free(png_ptr, info_ptr->splt_palettes[num].entries);
|
| - info_ptr->splt_palettes[num].name = NULL;
|
| - info_ptr->splt_palettes[num].entries = NULL;
|
| - }
|
| - }
|
| -
|
| - else
|
| - {
|
| - if (info_ptr->splt_palettes_num)
|
| - {
|
| - int i;
|
| - for (i = 0; i < info_ptr->splt_palettes_num; i++)
|
| - png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, (int)i);
|
| -
|
| - png_free(png_ptr, info_ptr->splt_palettes);
|
| - info_ptr->splt_palettes = NULL;
|
| - info_ptr->splt_palettes_num = 0;
|
| - }
|
| - info_ptr->valid &= ~PNG_INFO_sPLT;
|
| - }
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
|
| - if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
|
| - {
|
| - if (num != -1)
|
| - {
|
| - if (info_ptr->unknown_chunks)
|
| - {
|
| - png_free(png_ptr, info_ptr->unknown_chunks[num].data);
|
| - info_ptr->unknown_chunks[num].data = NULL;
|
| - }
|
| - }
|
| -
|
| - else
|
| - {
|
| - int i;
|
| -
|
| - if (info_ptr->unknown_chunks_num)
|
| - {
|
| - for (i = 0; i < info_ptr->unknown_chunks_num; i++)
|
| - png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, (int)i);
|
| -
|
| - png_free(png_ptr, info_ptr->unknown_chunks);
|
| - info_ptr->unknown_chunks = NULL;
|
| - info_ptr->unknown_chunks_num = 0;
|
| - }
|
| - }
|
| - }
|
| -#endif
|
| -
|
| -#ifdef PNG_hIST_SUPPORTED
|
| - /* Free any hIST entry */
|
| - if ((mask & PNG_FREE_HIST) & info_ptr->free_me)
|
| - {
|
| - png_free(png_ptr, info_ptr->hist);
|
| - info_ptr->hist = NULL;
|
| - info_ptr->valid &= ~PNG_INFO_hIST;
|
| - }
|
| -#endif
|
| -
|
| - /* Free any PLTE entry that was internally allocated */
|
| - if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
|
| - {
|
| - png_free(png_ptr, info_ptr->palette);
|
| - info_ptr->palette = NULL;
|
| - info_ptr->valid &= ~PNG_INFO_PLTE;
|
| - info_ptr->num_palette = 0;
|
| - }
|
| -
|
| -#ifdef PNG_INFO_IMAGE_SUPPORTED
|
| - /* Free any image bits attached to the info structure */
|
| - if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
|
| - {
|
| - if (info_ptr->row_pointers)
|
| - {
|
| - png_uint_32 row;
|
| - for (row = 0; row < info_ptr->height; row++)
|
| - {
|
| - png_free(png_ptr, info_ptr->row_pointers[row]);
|
| - info_ptr->row_pointers[row] = NULL;
|
| - }
|
| - png_free(png_ptr, info_ptr->row_pointers);
|
| - info_ptr->row_pointers = NULL;
|
| - }
|
| - info_ptr->valid &= ~PNG_INFO_IDAT;
|
| - }
|
| -#endif
|
| -
|
| - if (num != -1)
|
| - mask &= ~PNG_FREE_MUL;
|
| -
|
| - info_ptr->free_me &= ~mask;
|
| -}
|
| -#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
|
| -
|
| -/* This function returns a pointer to the io_ptr associated with the user
|
| - * functions. The application should free any memory associated with this
|
| - * pointer before png_write_destroy() or png_read_destroy() are called.
|
| - */
|
| -png_voidp PNGAPI
|
| -png_get_io_ptr(png_const_structrp png_ptr)
|
| -{
|
| - if (png_ptr == NULL)
|
| - return (NULL);
|
| -
|
| - return (png_ptr->io_ptr);
|
| -}
|
| -
|
| -#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
|
| -# ifdef PNG_STDIO_SUPPORTED
|
| -/* Initialize the default input/output functions for the PNG file. If you
|
| - * use your own read or write routines, you can call either png_set_read_fn()
|
| - * or png_set_write_fn() instead of png_init_io(). If you have defined
|
| - * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
|
| - * function of your own because "FILE *" isn't necessarily available.
|
| - */
|
| -void PNGAPI
|
| -png_init_io(png_structrp png_ptr, png_FILE_p fp)
|
| -{
|
| - png_debug(1, "in png_init_io");
|
| -
|
| - if (png_ptr == NULL)
|
| - return;
|
| -
|
| - png_ptr->io_ptr = (png_voidp)fp;
|
| -}
|
| -# endif
|
| -
|
| -#ifdef PNG_SAVE_INT_32_SUPPORTED
|
| -/* The png_save_int_32 function assumes integers are stored in two's
|
| - * complement format. If this isn't the case, then this routine needs to
|
| - * be modified to write data in two's complement format. Note that,
|
| - * the following works correctly even if png_int_32 has more than 32 bits
|
| - * (compare the more complex code required on read for sign extension.)
|
| - */
|
| -void PNGAPI
|
| -png_save_int_32(png_bytep buf, png_int_32 i)
|
| -{
|
| - buf[0] = (png_byte)((i >> 24) & 0xff);
|
| - buf[1] = (png_byte)((i >> 16) & 0xff);
|
| - buf[2] = (png_byte)((i >> 8) & 0xff);
|
| - buf[3] = (png_byte)(i & 0xff);
|
| -}
|
| -#endif
|
| -
|
| -# ifdef PNG_TIME_RFC1123_SUPPORTED
|
| -/* Convert the supplied time into an RFC 1123 string suitable for use in
|
| - * a "Creation Time" or other text-based time string.
|
| - */
|
| -int PNGAPI
|
| -png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
|
| -{
|
| - static PNG_CONST char short_months[12][4] =
|
| - {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
|
| - "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
|
| -
|
| - if (out == NULL)
|
| - return 0;
|
| -
|
| - if (ptime->year > 9999 /* RFC1123 limitation */ ||
|
| - ptime->month == 0 || ptime->month > 12 ||
|
| - ptime->day == 0 || ptime->day > 31 ||
|
| - ptime->hour > 23 || ptime->minute > 59 ||
|
| - ptime->second > 60)
|
| - return 0;
|
| -
|
| - {
|
| - size_t pos = 0;
|
| - char number_buf[5]; /* enough for a four-digit year */
|
| -
|
| -# define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
|
| -# define APPEND_NUMBER(format, value)\
|
| - APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
|
| -# define APPEND(ch) if (pos < 28) out[pos++] = (ch)
|
| -
|
| - APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
|
| - APPEND(' ');
|
| - APPEND_STRING(short_months[(ptime->month - 1)]);
|
| - APPEND(' ');
|
| - APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
|
| - APPEND(' ');
|
| - APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
|
| - APPEND(':');
|
| - APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
|
| - APPEND(':');
|
| - APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
|
| - APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
|
| -
|
| -# undef APPEND
|
| -# undef APPEND_NUMBER
|
| -# undef APPEND_STRING
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -# if PNG_LIBPNG_VER < 10700
|
| -/* To do: remove the following from libpng-1.7 */
|
| -/* Original API that uses a private buffer in png_struct.
|
| - * Deprecated because it causes png_struct to carry a spurious temporary
|
| - * buffer (png_struct::time_buffer), better to have the caller pass this in.
|
| - */
|
| -png_const_charp PNGAPI
|
| -png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
|
| -{
|
| - if (png_ptr != NULL)
|
| - {
|
| - /* The only failure above if png_ptr != NULL is from an invalid ptime */
|
| - if (!png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime))
|
| - png_warning(png_ptr, "Ignoring invalid time value");
|
| -
|
| - else
|
| - return png_ptr->time_buffer;
|
| - }
|
| -
|
| - return NULL;
|
| -}
|
| -# endif
|
| -# endif /* PNG_TIME_RFC1123_SUPPORTED */
|
| -
|
| -#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
|
| -
|
| -png_const_charp PNGAPI
|
| -png_get_copyright(png_const_structrp png_ptr)
|
| -{
|
| - PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
|
| -#ifdef PNG_STRING_COPYRIGHT
|
| - return PNG_STRING_COPYRIGHT
|
| -#else
|
| -# ifdef __STDC__
|
| - return PNG_STRING_NEWLINE \
|
| - "libpng version 1.6.3 - July 18, 2013" PNG_STRING_NEWLINE \
|
| - "Copyright (c) 1998-2013 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
|
| - "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
|
| - "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
|
| - PNG_STRING_NEWLINE;
|
| -# else
|
| - return "libpng version 1.6.3 - July 18, 2013\
|
| - Copyright (c) 1998-2013 Glenn Randers-Pehrson\
|
| - Copyright (c) 1996-1997 Andreas Dilger\
|
| - Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
|
| -# endif
|
| -#endif
|
| -}
|
| -
|
| -/* The following return the library version as a short string in the
|
| - * format 1.0.0 through 99.99.99zz. To get the version of *.h files
|
| - * used with your application, print out PNG_LIBPNG_VER_STRING, which
|
| - * is defined in png.h.
|
| - * Note: now there is no difference between png_get_libpng_ver() and
|
| - * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
|
| - * it is guaranteed that png.c uses the correct version of png.h.
|
| - */
|
| -png_const_charp PNGAPI
|
| -png_get_libpng_ver(png_const_structrp png_ptr)
|
| -{
|
| - /* Version of *.c files used when building libpng */
|
| - return png_get_header_ver(png_ptr);
|
| -}
|
| -
|
| -png_const_charp PNGAPI
|
| -png_get_header_ver(png_const_structrp png_ptr)
|
| -{
|
| - /* Version of *.h files used when building libpng */
|
| - PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
|
| - return PNG_LIBPNG_VER_STRING;
|
| -}
|
| -
|
| -png_const_charp PNGAPI
|
| -png_get_header_version(png_const_structrp png_ptr)
|
| -{
|
| - /* Returns longer string containing both version and date */
|
| - PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
|
| -#ifdef __STDC__
|
| - return PNG_HEADER_VERSION_STRING
|
| -# ifndef PNG_READ_SUPPORTED
|
| - " (NO READ SUPPORT)"
|
| -# endif
|
| - PNG_STRING_NEWLINE;
|
| -#else
|
| - return PNG_HEADER_VERSION_STRING;
|
| -#endif
|
| -}
|
| -
|
| -#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
|
| -int PNGAPI
|
| -png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
|
| -{
|
| - /* Check chunk_name and return "keep" value if it's on the list, else 0 */
|
| - png_const_bytep p, p_end;
|
| -
|
| - if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
|
| - return PNG_HANDLE_CHUNK_AS_DEFAULT;
|
| -
|
| - p_end = png_ptr->chunk_list;
|
| - p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
|
| -
|
| - /* The code is the fifth byte after each four byte string. Historically this
|
| - * code was always searched from the end of the list, this is no longer
|
| - * necessary because the 'set' routine handles duplicate entries correcty.
|
| - */
|
| - do /* num_chunk_list > 0, so at least one */
|
| - {
|
| - p -= 5;
|
| -
|
| - if (!memcmp(chunk_name, p, 4))
|
| - return p[4];
|
| - }
|
| - while (p > p_end);
|
| -
|
| - /* This means that known chunks should be processed and unknown chunks should
|
| - * be handled according to the value of png_ptr->unknown_default; this can be
|
| - * confusing because, as a result, there are two levels of defaulting for
|
| - * unknown chunks.
|
| - */
|
| - return PNG_HANDLE_CHUNK_AS_DEFAULT;
|
| -}
|
| -
|
| -#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
|
| -int /* PRIVATE */
|
| -png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
|
| -{
|
| - png_byte chunk_string[5];
|
| -
|
| - PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
|
| - return png_handle_as_unknown(png_ptr, chunk_string);
|
| -}
|
| -#endif /* READ_UNKNOWN_CHUNKS */
|
| -#endif /* SET_UNKNOWN_CHUNKS */
|
| -
|
| -#ifdef PNG_READ_SUPPORTED
|
| -/* This function, added to libpng-1.0.6g, is untested. */
|
| -int PNGAPI
|
| -png_reset_zstream(png_structrp png_ptr)
|
| -{
|
| - if (png_ptr == NULL)
|
| - return Z_STREAM_ERROR;
|
| -
|
| - /* WARNING: this resets the window bits to the maximum! */
|
| - return (inflateReset(&png_ptr->zstream));
|
| -}
|
| -#endif /* PNG_READ_SUPPORTED */
|
| -
|
| -/* This function was added to libpng-1.0.7 */
|
| -png_uint_32 PNGAPI
|
| -png_access_version_number(void)
|
| -{
|
| - /* Version of *.c files used when building libpng */
|
| - return((png_uint_32)PNG_LIBPNG_VER);
|
| -}
|
| -
|
| -
|
| -
|
| -#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
|
| -/* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
|
| - * If it doesn't 'ret' is used to set it to something appropriate, even in cases
|
| - * like Z_OK or Z_STREAM_END where the error code is apparently a success code.
|
| - */
|
| -void /* PRIVATE */
|
| -png_zstream_error(png_structrp png_ptr, int ret)
|
| -{
|
| - /* Translate 'ret' into an appropriate error string, priority is given to the
|
| - * one in zstream if set. This always returns a string, even in cases like
|
| - * Z_OK or Z_STREAM_END where the error code is a success code.
|
| - */
|
| - if (png_ptr->zstream.msg == NULL) switch (ret)
|
| - {
|
| - default:
|
| - case Z_OK:
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
|
| - break;
|
| -
|
| - case Z_STREAM_END:
|
| - /* Normal exit */
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
|
| - break;
|
| -
|
| - case Z_NEED_DICT:
|
| - /* This means the deflate stream did not have a dictionary; this
|
| - * indicates a bogus PNG.
|
| - */
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
|
| - break;
|
| -
|
| - case Z_ERRNO:
|
| - /* gz APIs only: should not happen */
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error");
|
| - break;
|
| -
|
| - case Z_STREAM_ERROR:
|
| - /* internal libpng error */
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib");
|
| - break;
|
| -
|
| - case Z_DATA_ERROR:
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream");
|
| - break;
|
| -
|
| - case Z_MEM_ERROR:
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory");
|
| - break;
|
| -
|
| - case Z_BUF_ERROR:
|
| - /* End of input or output; not a problem if the caller is doing
|
| - * incremental read or write.
|
| - */
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated");
|
| - break;
|
| -
|
| - case Z_VERSION_ERROR:
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version");
|
| - break;
|
| -
|
| - case PNG_UNEXPECTED_ZLIB_RETURN:
|
| - /* Compile errors here mean that zlib now uses the value co-opted in
|
| - * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above
|
| - * and change pngpriv.h. Note that this message is "... return",
|
| - * whereas the default/Z_OK one is "... return code".
|
| - */
|
| - png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return");
|
| - break;
|
| - }
|
| -}
|
| -
|
| -/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
|
| - * at libpng 1.5.5!
|
| - */
|
| -
|
| -/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
|
| -#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */
|
| -static int
|
| -png_colorspace_check_gamma(png_const_structrp png_ptr,
|
| - png_colorspacerp colorspace, png_fixed_point gAMA, int from)
|
| - /* This is called to check a new gamma value against an existing one. The
|
| - * routine returns false if the new gamma value should not be written.
|
| - *
|
| - * 'from' says where the new gamma value comes from:
|
| - *
|
| - * 0: the new gamma value is the libpng estimate for an ICC profile
|
| - * 1: the new gamma value comes from a gAMA chunk
|
| - * 2: the new gamma value comes from an sRGB chunk
|
| - */
|
| -{
|
| - png_fixed_point gtest;
|
| -
|
| - if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
|
| - (!png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) ||
|
| - png_gamma_significant(gtest)))
|
| - {
|
| - /* Either this is an sRGB image, in which case the calculated gamma
|
| - * approximation should match, or this is an image with a profile and the
|
| - * value libpng calculates for the gamma of the profile does not match the
|
| - * value recorded in the file. The former, sRGB, case is an error, the
|
| - * latter is just a warning.
|
| - */
|
| - if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2)
|
| - {
|
| - png_chunk_report(png_ptr, "gamma value does not match sRGB",
|
| - PNG_CHUNK_ERROR);
|
| - /* Do not overwrite an sRGB value */
|
| - return from == 2;
|
| - }
|
| -
|
| - else /* sRGB tag not involved */
|
| - {
|
| - png_chunk_report(png_ptr, "gamma value does not match libpng estimate",
|
| - PNG_CHUNK_WARNING);
|
| - return from == 1;
|
| - }
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -void /* PRIVATE */
|
| -png_colorspace_set_gamma(png_const_structrp png_ptr,
|
| - png_colorspacerp colorspace, png_fixed_point gAMA)
|
| -{
|
| - /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
|
| - * occur. Since the fixed point representation is assymetrical it is
|
| - * possible for 1/gamma to overflow the limit of 21474 and this means the
|
| - * gamma value must be at least 5/100000 and hence at most 20000.0. For
|
| - * safety the limits here are a little narrower. The values are 0.00016 to
|
| - * 6250.0, which are truly ridiculous gamma values (and will produce
|
| - * displays that are all black or all white.)
|
| - *
|
| - * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk
|
| - * handling code, which only required the value to be >0.
|
| - */
|
| - png_const_charp errmsg;
|
| -
|
| - if (gAMA < 16 || gAMA > 625000000)
|
| - errmsg = "gamma value out of range";
|
| -
|
| -# ifdef PNG_READ_gAMA_SUPPORTED
|
| - /* Allow the application to set the gamma value more than once */
|
| - else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
|
| - (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
|
| - errmsg = "duplicate";
|
| -# endif
|
| -
|
| - /* Do nothing if the colorspace is already invalid */
|
| - else if (colorspace->flags & PNG_COLORSPACE_INVALID)
|
| - return;
|
| -
|
| - else
|
| - {
|
| - if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA, 1/*from gAMA*/))
|
| - {
|
| - /* Store this gamma value. */
|
| - colorspace->gamma = gAMA;
|
| - colorspace->flags |=
|
| - (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA);
|
| - }
|
| -
|
| - /* At present if the check_gamma test fails the gamma of the colorspace is
|
| - * not updated however the colorspace is not invalidated. This
|
| - * corresponds to the case where the existing gamma comes from an sRGB
|
| - * chunk or profile. An error message has already been output.
|
| - */
|
| - return;
|
| - }
|
| -
|
| - /* Error exit - errmsg has been set. */
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| - png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR);
|
| -}
|
| -
|
| -void /* PRIVATE */
|
| -png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
|
| -{
|
| - if (info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID)
|
| - {
|
| - /* Everything is invalid */
|
| - info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
|
| - PNG_INFO_iCCP);
|
| -
|
| -# ifdef PNG_COLORSPACE_SUPPORTED
|
| - /* Clean up the iCCP profile now if it won't be used. */
|
| - png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
|
| -# else
|
| - PNG_UNUSED(png_ptr)
|
| -# endif
|
| - }
|
| -
|
| - else
|
| - {
|
| -# ifdef PNG_COLORSPACE_SUPPORTED
|
| - /* Leave the INFO_iCCP flag set if the pngset.c code has already set
|
| - * it; this allows a PNG to contain a profile which matches sRGB and
|
| - * yet still have that profile retrievable by the application.
|
| - */
|
| - if (info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB)
|
| - info_ptr->valid |= PNG_INFO_sRGB;
|
| -
|
| - else
|
| - info_ptr->valid &= ~PNG_INFO_sRGB;
|
| -
|
| - if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS)
|
| - info_ptr->valid |= PNG_INFO_cHRM;
|
| -
|
| - else
|
| - info_ptr->valid &= ~PNG_INFO_cHRM;
|
| -# endif
|
| -
|
| - if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA)
|
| - info_ptr->valid |= PNG_INFO_gAMA;
|
| -
|
| - else
|
| - info_ptr->valid &= ~PNG_INFO_gAMA;
|
| - }
|
| -}
|
| -
|
| -#ifdef PNG_READ_SUPPORTED
|
| -void /* PRIVATE */
|
| -png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
|
| -{
|
| - if (info_ptr == NULL) /* reduce code size; check here not in the caller */
|
| - return;
|
| -
|
| - info_ptr->colorspace = png_ptr->colorspace;
|
| - png_colorspace_sync_info(png_ptr, info_ptr);
|
| -}
|
| -#endif
|
| -#endif
|
| -
|
| -#ifdef PNG_COLORSPACE_SUPPORTED
|
| -/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
|
| - * cHRM, as opposed to using chromaticities. These internal APIs return
|
| - * non-zero on a parameter error. The X, Y and Z values are required to be
|
| - * positive and less than 1.0.
|
| - */
|
| -static int
|
| -png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
|
| -{
|
| - png_int_32 d, dwhite, whiteX, whiteY;
|
| -
|
| - d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
|
| - if (!png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d)) return 1;
|
| - if (!png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d)) return 1;
|
| - dwhite = d;
|
| - whiteX = XYZ->red_X;
|
| - whiteY = XYZ->red_Y;
|
| -
|
| - d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
|
| - if (!png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d)) return 1;
|
| - if (!png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d)) return 1;
|
| - dwhite += d;
|
| - whiteX += XYZ->green_X;
|
| - whiteY += XYZ->green_Y;
|
| -
|
| - d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
|
| - if (!png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d)) return 1;
|
| - if (!png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d)) return 1;
|
| - dwhite += d;
|
| - whiteX += XYZ->blue_X;
|
| - whiteY += XYZ->blue_Y;
|
| -
|
| - /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
|
| - * thus:
|
| - */
|
| - if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1;
|
| - if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1;
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -static int
|
| -png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
|
| -{
|
| - png_fixed_point red_inverse, green_inverse, blue_scale;
|
| - png_fixed_point left, right, denominator;
|
| -
|
| - /* Check xy and, implicitly, z. Note that wide gamut color spaces typically
|
| - * have end points with 0 tristimulus values (these are impossible end
|
| - * points, but they are used to cover the possible colors.)
|
| - */
|
| - if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1;
|
| - if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
|
| - if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
|
| - if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
|
| - if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1;
|
| - if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
|
| - if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
|
| - if (xy->whitey < 0 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
|
| -
|
| - /* The reverse calculation is more difficult because the original tristimulus
|
| - * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
|
| - * derived values were recorded in the cHRM chunk;
|
| - * (red,green,blue,white)x(x,y). This loses one degree of freedom and
|
| - * therefore an arbitrary ninth value has to be introduced to undo the
|
| - * original transformations.
|
| - *
|
| - * Think of the original end-points as points in (X,Y,Z) space. The
|
| - * chromaticity values (c) have the property:
|
| - *
|
| - * C
|
| - * c = ---------
|
| - * X + Y + Z
|
| - *
|
| - * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the
|
| - * three chromaticity values (x,y,z) for each end-point obey the
|
| - * relationship:
|
| - *
|
| - * x + y + z = 1
|
| - *
|
| - * This describes the plane in (X,Y,Z) space that intersects each axis at the
|
| - * value 1.0; call this the chromaticity plane. Thus the chromaticity
|
| - * calculation has scaled each end-point so that it is on the x+y+z=1 plane
|
| - * and chromaticity is the intersection of the vector from the origin to the
|
| - * (X,Y,Z) value with the chromaticity plane.
|
| - *
|
| - * To fully invert the chromaticity calculation we would need the three
|
| - * end-point scale factors, (red-scale, green-scale, blue-scale), but these
|
| - * were not recorded. Instead we calculated the reference white (X,Y,Z) and
|
| - * recorded the chromaticity of this. The reference white (X,Y,Z) would have
|
| - * given all three of the scale factors since:
|
| - *
|
| - * color-C = color-c * color-scale
|
| - * white-C = red-C + green-C + blue-C
|
| - * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
|
| - *
|
| - * But cHRM records only white-x and white-y, so we have lost the white scale
|
| - * factor:
|
| - *
|
| - * white-C = white-c*white-scale
|
| - *
|
| - * To handle this the inverse transformation makes an arbitrary assumption
|
| - * about white-scale:
|
| - *
|
| - * Assume: white-Y = 1.0
|
| - * Hence: white-scale = 1/white-y
|
| - * Or: red-Y + green-Y + blue-Y = 1.0
|
| - *
|
| - * Notice the last statement of the assumption gives an equation in three of
|
| - * the nine values we want to calculate. 8 more equations come from the
|
| - * above routine as summarised at the top above (the chromaticity
|
| - * calculation):
|
| - *
|
| - * Given: color-x = color-X / (color-X + color-Y + color-Z)
|
| - * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
|
| - *
|
| - * This is 9 simultaneous equations in the 9 variables "color-C" and can be
|
| - * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix
|
| - * determinants, however this is not as bad as it seems because only 28 of
|
| - * the total of 90 terms in the various matrices are non-zero. Nevertheless
|
| - * Cramer's rule is notoriously numerically unstable because the determinant
|
| - * calculation involves the difference of large, but similar, numbers. It is
|
| - * difficult to be sure that the calculation is stable for real world values
|
| - * and it is certain that it becomes unstable where the end points are close
|
| - * together.
|
| - *
|
| - * So this code uses the perhaps slightly less optimal but more
|
| - * understandable and totally obvious approach of calculating color-scale.
|
| - *
|
| - * This algorithm depends on the precision in white-scale and that is
|
| - * (1/white-y), so we can immediately see that as white-y approaches 0 the
|
| - * accuracy inherent in the cHRM chunk drops off substantially.
|
| - *
|
| - * libpng arithmetic: a simple invertion of the above equations
|
| - * ------------------------------------------------------------
|
| - *
|
| - * white_scale = 1/white-y
|
| - * white-X = white-x * white-scale
|
| - * white-Y = 1.0
|
| - * white-Z = (1 - white-x - white-y) * white_scale
|
| - *
|
| - * white-C = red-C + green-C + blue-C
|
| - * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
|
| - *
|
| - * This gives us three equations in (red-scale,green-scale,blue-scale) where
|
| - * all the coefficients are now known:
|
| - *
|
| - * red-x*red-scale + green-x*green-scale + blue-x*blue-scale
|
| - * = white-x/white-y
|
| - * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
|
| - * red-z*red-scale + green-z*green-scale + blue-z*blue-scale
|
| - * = (1 - white-x - white-y)/white-y
|
| - *
|
| - * In the last equation color-z is (1 - color-x - color-y) so we can add all
|
| - * three equations together to get an alternative third:
|
| - *
|
| - * red-scale + green-scale + blue-scale = 1/white-y = white-scale
|
| - *
|
| - * So now we have a Cramer's rule solution where the determinants are just
|
| - * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve
|
| - * multiplication of three coefficients so we can't guarantee to avoid
|
| - * overflow in the libpng fixed point representation. Using Cramer's rule in
|
| - * floating point is probably a good choice here, but it's not an option for
|
| - * fixed point. Instead proceed to simplify the first two equations by
|
| - * eliminating what is likely to be the largest value, blue-scale:
|
| - *
|
| - * blue-scale = white-scale - red-scale - green-scale
|
| - *
|
| - * Hence:
|
| - *
|
| - * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
|
| - * (white-x - blue-x)*white-scale
|
| - *
|
| - * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
|
| - * 1 - blue-y*white-scale
|
| - *
|
| - * And now we can trivially solve for (red-scale,green-scale):
|
| - *
|
| - * green-scale =
|
| - * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
|
| - * -----------------------------------------------------------
|
| - * green-x - blue-x
|
| - *
|
| - * red-scale =
|
| - * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale
|
| - * ---------------------------------------------------------
|
| - * red-y - blue-y
|
| - *
|
| - * Hence:
|
| - *
|
| - * red-scale =
|
| - * ( (green-x - blue-x) * (white-y - blue-y) -
|
| - * (green-y - blue-y) * (white-x - blue-x) ) / white-y
|
| - * -------------------------------------------------------------------------
|
| - * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
|
| - *
|
| - * green-scale =
|
| - * ( (red-y - blue-y) * (white-x - blue-x) -
|
| - * (red-x - blue-x) * (white-y - blue-y) ) / white-y
|
| - * -------------------------------------------------------------------------
|
| - * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
|
| - *
|
| - * Accuracy:
|
| - * The input values have 5 decimal digits of accuracy. The values are all in
|
| - * the range 0 < value < 1, so simple products are in the same range but may
|
| - * need up to 10 decimal digits to preserve the original precision and avoid
|
| - * underflow. Because we are using a 32-bit signed representation we cannot
|
| - * match this; the best is a little over 9 decimal digits, less than 10.
|
| - *
|
| - * The approach used here is to preserve the maximum precision within the
|
| - * signed representation. Because the red-scale calculation above uses the
|
| - * difference between two products of values that must be in the range -1..+1
|
| - * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The
|
| - * factor is irrelevant in the calculation because it is applied to both
|
| - * numerator and denominator.
|
| - *
|
| - * Note that the values of the differences of the products of the
|
| - * chromaticities in the above equations tend to be small, for example for
|
| - * the sRGB chromaticities they are:
|
| - *
|
| - * red numerator: -0.04751
|
| - * green numerator: -0.08788
|
| - * denominator: -0.2241 (without white-y multiplication)
|
| - *
|
| - * The resultant Y coefficients from the chromaticities of some widely used
|
| - * color space definitions are (to 15 decimal places):
|
| - *
|
| - * sRGB
|
| - * 0.212639005871510 0.715168678767756 0.072192315360734
|
| - * Kodak ProPhoto
|
| - * 0.288071128229293 0.711843217810102 0.000085653960605
|
| - * Adobe RGB
|
| - * 0.297344975250536 0.627363566255466 0.075291458493998
|
| - * Adobe Wide Gamut RGB
|
| - * 0.258728243040113 0.724682314948566 0.016589442011321
|
| - */
|
| - /* By the argument, above overflow should be impossible here. The return
|
| - * value of 2 indicates an internal error to the caller.
|
| - */
|
| - if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7))
|
| - return 2;
|
| - if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7))
|
| - return 2;
|
| - denominator = left - right;
|
| -
|
| - /* Now find the red numerator. */
|
| - if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7))
|
| - return 2;
|
| - if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7))
|
| - return 2;
|
| -
|
| - /* Overflow is possible here and it indicates an extreme set of PNG cHRM
|
| - * chunk values. This calculation actually returns the reciprocal of the
|
| - * scale value because this allows us to delay the multiplication of white-y
|
| - * into the denominator, which tends to produce a small number.
|
| - */
|
| - if (!png_muldiv(&red_inverse, xy->whitey, denominator, left-right) ||
|
| - red_inverse <= xy->whitey /* r+g+b scales = white scale */)
|
| - return 1;
|
| -
|
| - /* Similarly for green_inverse: */
|
| - if (!png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7))
|
| - return 2;
|
| - if (!png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7))
|
| - return 2;
|
| - if (!png_muldiv(&green_inverse, xy->whitey, denominator, left-right) ||
|
| - green_inverse <= xy->whitey)
|
| - return 1;
|
| -
|
| - /* And the blue scale, the checks above guarantee this can't overflow but it
|
| - * can still produce 0 for extreme cHRM values.
|
| - */
|
| - blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
|
| - png_reciprocal(green_inverse);
|
| - if (blue_scale <= 0) return 1;
|
| -
|
| -
|
| - /* And fill in the png_XYZ: */
|
| - if (!png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse)) return 1;
|
| - if (!png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse)) return 1;
|
| - if (!png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
|
| - red_inverse))
|
| - return 1;
|
| -
|
| - if (!png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse))
|
| - return 1;
|
| - if (!png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse))
|
| - return 1;
|
| - if (!png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
|
| - green_inverse))
|
| - return 1;
|
| -
|
| - if (!png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1)) return 1;
|
| - if (!png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1)) return 1;
|
| - if (!png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
|
| - PNG_FP_1))
|
| - return 1;
|
| -
|
| - return 0; /*success*/
|
| -}
|
| -
|
| -static int
|
| -png_XYZ_normalize(png_XYZ *XYZ)
|
| -{
|
| - png_int_32 Y;
|
| -
|
| - if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 ||
|
| - XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 ||
|
| - XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0)
|
| - return 1;
|
| -
|
| - /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1.
|
| - * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore
|
| - * relying on addition of two positive values producing a negative one is not
|
| - * safe.
|
| - */
|
| - Y = XYZ->red_Y;
|
| - if (0x7fffffff - Y < XYZ->green_X) return 1;
|
| - Y += XYZ->green_Y;
|
| - if (0x7fffffff - Y < XYZ->blue_X) return 1;
|
| - Y += XYZ->blue_Y;
|
| -
|
| - if (Y != PNG_FP_1)
|
| - {
|
| - if (!png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y)) return 1;
|
| - if (!png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y)) return 1;
|
| - if (!png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y)) return 1;
|
| -
|
| - if (!png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y)) return 1;
|
| - if (!png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y)) return 1;
|
| - if (!png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y)) return 1;
|
| -
|
| - if (!png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y)) return 1;
|
| - if (!png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y)) return 1;
|
| - if (!png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y)) return 1;
|
| - }
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -static int
|
| -png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
|
| -{
|
| - /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
|
| - return !(PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) ||
|
| - PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta));
|
| -}
|
| -
|
| -/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
|
| - * chunk chromaticities. Earlier checks used to simply look for the overflow
|
| - * condition (where the determinant of the matrix to solve for XYZ ends up zero
|
| - * because the chromaticity values are not all distinct.) Despite this it is
|
| - * theoretically possible to produce chromaticities that are apparently valid
|
| - * but that rapidly degrade to invalid, potentially crashing, sets because of
|
| - * arithmetic inaccuracies when calculations are performed on them. The new
|
| - * check is to round-trip xy -> XYZ -> xy and then check that the result is
|
| - * within a small percentage of the original.
|
| - */
|
| -static int
|
| -png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)
|
| -{
|
| - int result;
|
| - png_xy xy_test;
|
| -
|
| - /* As a side-effect this routine also returns the XYZ endpoints. */
|
| - result = png_XYZ_from_xy(XYZ, xy);
|
| - if (result) return result;
|
| -
|
| - result = png_xy_from_XYZ(&xy_test, XYZ);
|
| - if (result) return result;
|
| -
|
| - if (png_colorspace_endpoints_match(xy, &xy_test,
|
| - 5/*actually, the math is pretty accurate*/))
|
| - return 0;
|
| -
|
| - /* Too much slip */
|
| - return 1;
|
| -}
|
| -
|
| -/* This is the check going the other way. The XYZ is modified to normalize it
|
| - * (another side-effect) and the xy chromaticities are returned.
|
| - */
|
| -static int
|
| -png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
|
| -{
|
| - int result;
|
| - png_XYZ XYZtemp;
|
| -
|
| - result = png_XYZ_normalize(XYZ);
|
| - if (result) return result;
|
| -
|
| - result = png_xy_from_XYZ(xy, XYZ);
|
| - if (result) return result;
|
| -
|
| - XYZtemp = *XYZ;
|
| - return png_colorspace_check_xy(&XYZtemp, xy);
|
| -}
|
| -
|
| -/* Used to check for an endpoint match against sRGB */
|
| -static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
|
| -{
|
| - /* color x y */
|
| - /* red */ 64000, 33000,
|
| - /* green */ 30000, 60000,
|
| - /* blue */ 15000, 6000,
|
| - /* white */ 31270, 32900
|
| -};
|
| -
|
| -static int
|
| -png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
|
| - png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
|
| - int preferred)
|
| -{
|
| - if (colorspace->flags & PNG_COLORSPACE_INVALID)
|
| - return 0;
|
| -
|
| - /* The consistency check is performed on the chromaticities; this factors out
|
| - * variations because of the normalization (or not) of the end point Y
|
| - * values.
|
| - */
|
| - if (preferred < 2 && (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS))
|
| - {
|
| - /* The end points must be reasonably close to any we already have. The
|
| - * following allows an error of up to +/-.001
|
| - */
|
| - if (!png_colorspace_endpoints_match(xy, &colorspace->end_points_xy, 100))
|
| - {
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| - png_benign_error(png_ptr, "inconsistent chromaticities");
|
| - return 0; /* failed */
|
| - }
|
| -
|
| - /* Only overwrite with preferred values */
|
| - if (!preferred)
|
| - return 1; /* ok, but no change */
|
| - }
|
| -
|
| - colorspace->end_points_xy = *xy;
|
| - colorspace->end_points_XYZ = *XYZ;
|
| - colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS;
|
| -
|
| - /* The end points are normally quoted to two decimal digits, so allow +/-0.01
|
| - * on this test.
|
| - */
|
| - if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000))
|
| - colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;
|
| -
|
| - else
|
| - colorspace->flags &= PNG_COLORSPACE_CANCEL(
|
| - PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
|
| -
|
| - return 2; /* ok and changed */
|
| -}
|
| -
|
| -int /* PRIVATE */
|
| -png_colorspace_set_chromaticities(png_const_structrp png_ptr,
|
| - png_colorspacerp colorspace, const png_xy *xy, int preferred)
|
| -{
|
| - /* We must check the end points to ensure they are reasonable - in the past
|
| - * color management systems have crashed as a result of getting bogus
|
| - * colorant values, while this isn't the fault of libpng it is the
|
| - * responsibility of libpng because PNG carries the bomb and libpng is in a
|
| - * position to protect against it.
|
| - */
|
| - png_XYZ XYZ;
|
| -
|
| - switch (png_colorspace_check_xy(&XYZ, xy))
|
| - {
|
| - case 0: /* success */
|
| - return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ,
|
| - preferred);
|
| -
|
| - case 1:
|
| - /* We can't invert the chromaticities so we can't produce value XYZ
|
| - * values. Likely as not a color management system will fail too.
|
| - */
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| - png_benign_error(png_ptr, "invalid chromaticities");
|
| - break;
|
| -
|
| - default:
|
| - /* libpng is broken; this should be a warning but if it happens we
|
| - * want error reports so for the moment it is an error.
|
| - */
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| - png_error(png_ptr, "internal error checking chromaticities");
|
| - break;
|
| - }
|
| -
|
| - return 0; /* failed */
|
| -}
|
| -
|
| -int /* PRIVATE */
|
| -png_colorspace_set_endpoints(png_const_structrp png_ptr,
|
| - png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred)
|
| -{
|
| - png_XYZ XYZ = *XYZ_in;
|
| - png_xy xy;
|
| -
|
| - switch (png_colorspace_check_XYZ(&xy, &XYZ))
|
| - {
|
| - case 0:
|
| - return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ,
|
| - preferred);
|
| -
|
| - case 1:
|
| - /* End points are invalid. */
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| - png_benign_error(png_ptr, "invalid end points");
|
| - break;
|
| -
|
| - default:
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| - png_error(png_ptr, "internal error checking chromaticities");
|
| - break;
|
| - }
|
| -
|
| - return 0; /* failed */
|
| -}
|
| -
|
| -#if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED)
|
| -/* Error message generation */
|
| -static char
|
| -png_icc_tag_char(png_uint_32 byte)
|
| -{
|
| - byte &= 0xff;
|
| - if (byte >= 32 && byte <= 126)
|
| - return (char)byte;
|
| - else
|
| - return '?';
|
| -}
|
| -
|
| -static void
|
| -png_icc_tag_name(char *name, png_uint_32 tag)
|
| -{
|
| - name[0] = '\'';
|
| - name[1] = png_icc_tag_char(tag >> 24);
|
| - name[2] = png_icc_tag_char(tag >> 16);
|
| - name[3] = png_icc_tag_char(tag >> 8);
|
| - name[4] = png_icc_tag_char(tag );
|
| - name[5] = '\'';
|
| -}
|
| -
|
| -static int
|
| -is_ICC_signature_char(png_alloc_size_t it)
|
| -{
|
| - return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) ||
|
| - (it >= 97 && it <= 122);
|
| -}
|
| -
|
| -static int is_ICC_signature(png_alloc_size_t it)
|
| -{
|
| - return is_ICC_signature_char(it >> 24) /* checks all the top bits */ &&
|
| - is_ICC_signature_char((it >> 16) & 0xff) &&
|
| - is_ICC_signature_char((it >> 8) & 0xff) &&
|
| - is_ICC_signature_char(it & 0xff);
|
| -}
|
| -
|
| -static int
|
| -png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| - png_const_charp name, png_alloc_size_t value, png_const_charp reason)
|
| -{
|
| - size_t pos;
|
| - char message[196]; /* see below for calculation */
|
| -
|
| - if (colorspace != NULL)
|
| - colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| -
|
| - pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
|
| - pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
|
| - pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
|
| - if (is_ICC_signature(value))
|
| - {
|
| - /* So 'value' is at most 4 bytes and the following cast is safe */
|
| - png_icc_tag_name(message+pos, (png_uint_32)value);
|
| - pos += 6; /* total +8; less than the else clause */
|
| - message[pos++] = ':';
|
| - message[pos++] = ' ';
|
| - }
|
| -# ifdef PNG_WARNINGS_SUPPORTED
|
| - else
|
| - {
|
| - char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/
|
| -
|
| - pos = png_safecat(message, (sizeof message), pos,
|
| - png_format_number(number, number+(sizeof number),
|
| - PNG_NUMBER_FORMAT_x, value));
|
| - pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/
|
| - }
|
| -# endif
|
| - /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
|
| - pos = png_safecat(message, (sizeof message), pos, reason);
|
| -
|
| - /* This is recoverable, but make it unconditionally an app_error on write to
|
| - * avoid writing invalid ICC profiles into PNG files. (I.e. we handle them
|
| - * on read, with a warning, but on write unless the app turns off
|
| - * application errors the PNG won't be written.)
|
| - */
|
| - png_chunk_report(png_ptr, message,
|
| - (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR);
|
| -
|
| - return 0;
|
| -}
|
| -#endif /* sRGB || iCCP */
|
| -
|
| -#ifdef PNG_sRGB_SUPPORTED
|
| -int /* PRIVATE */
|
| -png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| - int intent)
|
| -{
|
| - /* sRGB sets known gamma, end points and (from the chunk) intent. */
|
| - /* IMPORTANT: these are not necessarily the values found in an ICC profile
|
| - * because ICC profiles store values adapted to a D50 environment; it is
|
| - * expected that the ICC profile mediaWhitePointTag will be D50, see the
|
| - * checks and code elsewhere to understand this better.
|
| - *
|
| - * These XYZ values, which are accurate to 5dp, produce rgb to gray
|
| - * coefficients of (6968,23435,2366), which are reduced (because they add up
|
| - * to 32769 not 32768) to (6968,23434,2366). These are the values that
|
| - * libpng has traditionally used (and are the best values given the 15bit
|
| - * algorithm used by the rgb to gray code.)
|
| - */
|
| - static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */
|
| - {
|
| - /* color X Y Z */
|
| - /* red */ 41239, 21264, 1933,
|
| - /* green */ 35758, 71517, 11919,
|
| - /* blue */ 18048, 7219, 95053
|
| - };
|
| -
|
| - /* Do nothing if the colorspace is already invalidated. */
|
| - if (colorspace->flags & PNG_COLORSPACE_INVALID)
|
| - return 0;
|
| -
|
| - /* Check the intent, then check for existing settings. It is valid for the
|
| - * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must
|
| - * be consistent with the correct values. If, however, this function is
|
| - * called below because an iCCP chunk matches sRGB then it is quite
|
| - * conceivable that an older app recorded incorrect gAMA and cHRM because of
|
| - * an incorrect calculation based on the values in the profile - this does
|
| - * *not* invalidate the profile (though it still produces an error, which can
|
| - * be ignored.)
|
| - */
|
| - if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
|
| - return png_icc_profile_error(png_ptr, colorspace, "sRGB",
|
| - (unsigned)intent, "invalid sRGB rendering intent");
|
| -
|
| - if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
|
| - colorspace->rendering_intent != intent)
|
| - return png_icc_profile_error(png_ptr, colorspace, "sRGB",
|
| - (unsigned)intent, "inconsistent rendering intents");
|
| -
|
| - if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
|
| - {
|
| - png_benign_error(png_ptr, "duplicate sRGB information ignored");
|
| - return 0;
|
| - }
|
| -
|
| - /* If the standard sRGB cHRM chunk does not match the one from the PNG file
|
| - * warn but overwrite the value with the correct one.
|
| - */
|
| - if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 &&
|
| - !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy,
|
| - 100))
|
| - png_chunk_report(png_ptr, "cHRM chunk does not match sRGB",
|
| - PNG_CHUNK_ERROR);
|
| -
|
| - /* This check is just done for the error reporting - the routine always
|
| - * returns true when the 'from' argument corresponds to sRGB (2).
|
| - */
|
| - (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE,
|
| - 2/*from sRGB*/);
|
| -
|
| - /* intent: bugs in GCC force 'int' to be used as the parameter type. */
|
| - colorspace->rendering_intent = (png_uint_16)intent;
|
| - colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT;
|
| -
|
| - /* endpoints */
|
| - colorspace->end_points_xy = sRGB_xy;
|
| - colorspace->end_points_XYZ = sRGB_XYZ;
|
| - colorspace->flags |=
|
| - (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
|
| -
|
| - /* gamma */
|
| - colorspace->gamma = PNG_GAMMA_sRGB_INVERSE;
|
| - colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
| -
|
| - /* Finally record that we have an sRGB profile */
|
| - colorspace->flags |=
|
| - (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB);
|
| -
|
| - return 1; /* set */
|
| -}
|
| -#endif /* sRGB */
|
| -
|
| -#ifdef PNG_iCCP_SUPPORTED
|
| -/* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value
|
| - * is XYZ(0.9642,1.0,0.8249), which scales to:
|
| - *
|
| - * (63189.8112, 65536, 54060.6464)
|
| - */
|
| -static const png_byte D50_nCIEXYZ[12] =
|
| - { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d };
|
| -
|
| -int /* PRIVATE */
|
| -png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| - png_const_charp name, png_uint_32 profile_length)
|
| -{
|
| - if (profile_length < 132)
|
| - return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
|
| - "too short");
|
| -
|
| - if (profile_length & 3)
|
| - return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
|
| - "invalid length");
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -int /* PRIVATE */
|
| -png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| - png_const_charp name, png_uint_32 profile_length,
|
| - png_const_bytep profile/* first 132 bytes only */, int color_type)
|
| -{
|
| - png_uint_32 temp;
|
| -
|
| - /* Length check; this cannot be ignored in this code because profile_length
|
| - * is used later to check the tag table, so even if the profile seems over
|
| - * long profile_length from the caller must be correct. The caller can fix
|
| - * this up on read or write by just passing in the profile header length.
|
| - */
|
| - temp = png_get_uint_32(profile);
|
| - if (temp != profile_length)
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "length does not match profile");
|
| -
|
| - temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */
|
| - if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */
|
| - profile_length < 132+12*temp) /* truncated tag table */
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "tag count too large");
|
| -
|
| - /* The 'intent' must be valid or we can't store it, ICC limits the intent to
|
| - * 16 bits.
|
| - */
|
| - temp = png_get_uint_32(profile+64);
|
| - if (temp >= 0xffff) /* The ICC limit */
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "invalid rendering intent");
|
| -
|
| - /* This is just a warning because the profile may be valid in future
|
| - * versions.
|
| - */
|
| - if (temp >= PNG_sRGB_INTENT_LAST)
|
| - (void)png_icc_profile_error(png_ptr, NULL, name, temp,
|
| - "intent outside defined range");
|
| -
|
| - /* At this point the tag table can't be checked because it hasn't necessarily
|
| - * been loaded; however, various header fields can be checked. These checks
|
| - * are for values permitted by the PNG spec in an ICC profile; the PNG spec
|
| - * restricts the profiles that can be passed in an iCCP chunk (they must be
|
| - * appropriate to processing PNG data!)
|
| - */
|
| -
|
| - /* Data checks (could be skipped). These checks must be independent of the
|
| - * version number; however, the version number doesn't accomodate changes in
|
| - * the header fields (just the known tags and the interpretation of the
|
| - * data.)
|
| - */
|
| - temp = png_get_uint_32(profile+36); /* signature 'ascp' */
|
| - if (temp != 0x61637370)
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "invalid signature");
|
| -
|
| - /* Currently the PCS illuminant/adopted white point (the computational
|
| - * white point) are required to be D50,
|
| - * however the profile contains a record of the illuminant so perhaps ICC
|
| - * expects to be able to change this in the future (despite the rationale in
|
| - * the introduction for using a fixed PCS adopted white.) Consequently the
|
| - * following is just a warning.
|
| - */
|
| - if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0)
|
| - (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/,
|
| - "PCS illuminant is not D50");
|
| -
|
| - /* The PNG spec requires this:
|
| - * "If the iCCP chunk is present, the image samples conform to the colour
|
| - * space represented by the embedded ICC profile as defined by the
|
| - * International Color Consortium [ICC]. The colour space of the ICC profile
|
| - * shall be an RGB colour space for colour images (PNG colour types 2, 3, and
|
| - * 6), or a greyscale colour space for greyscale images (PNG colour types 0
|
| - * and 4)."
|
| - *
|
| - * This checking code ensures the embedded profile (on either read or write)
|
| - * conforms to the specification requirements. Notice that an ICC 'gray'
|
| - * color-space profile contains the information to transform the monochrome
|
| - * data to XYZ or L*a*b (according to which PCS the profile uses) and this
|
| - * should be used in preference to the standard libpng K channel replication
|
| - * into R, G and B channels.
|
| - *
|
| - * Previously it was suggested that an RGB profile on grayscale data could be
|
| - * handled. However it it is clear that using an RGB profile in this context
|
| - * must be an error - there is no specification of what it means. Thus it is
|
| - * almost certainly more correct to ignore the profile.
|
| - */
|
| - temp = png_get_uint_32(profile+16); /* data colour space field */
|
| - switch (temp)
|
| - {
|
| - case 0x52474220: /* 'RGB ' */
|
| - if (!(color_type & PNG_COLOR_MASK_COLOR))
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "RGB color space not permitted on grayscale PNG");
|
| - break;
|
| -
|
| - case 0x47524159: /* 'GRAY' */
|
| - if (color_type & PNG_COLOR_MASK_COLOR)
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "Gray color space not permitted on RGB PNG");
|
| - break;
|
| -
|
| - default:
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "invalid ICC profile color space");
|
| - }
|
| -
|
| - /* It is up to the application to check that the profile class matches the
|
| - * application requirements; the spec provides no guidance, but it's pretty
|
| - * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer
|
| - * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these
|
| - * cases. Issue an error for device link or abstract profiles - these don't
|
| - * contain the records necessary to transform the color-space to anything
|
| - * other than the target device (and not even that for an abstract profile).
|
| - * Profiles of these classes may not be embedded in images.
|
| - */
|
| - temp = png_get_uint_32(profile+12); /* profile/device class */
|
| - switch (temp)
|
| - {
|
| - case 0x73636E72: /* 'scnr' */
|
| - case 0x6D6E7472: /* 'mntr' */
|
| - case 0x70727472: /* 'prtr' */
|
| - case 0x73706163: /* 'spac' */
|
| - /* All supported */
|
| - break;
|
| -
|
| - case 0x61627374: /* 'abst' */
|
| - /* May not be embedded in an image */
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "invalid embedded Abstract ICC profile");
|
| -
|
| - case 0x6C696E6B: /* 'link' */
|
| - /* DeviceLink profiles cannnot be interpreted in a non-device specific
|
| - * fashion, if an app uses the AToB0Tag in the profile the results are
|
| - * undefined unless the result is sent to the intended device,
|
| - * therefore a DeviceLink profile should not be found embedded in a
|
| - * PNG.
|
| - */
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "unexpected DeviceLink ICC profile class");
|
| -
|
| - case 0x6E6D636C: /* 'nmcl' */
|
| - /* A NamedColor profile is also device specific, however it doesn't
|
| - * contain an AToB0 tag that is open to misintrepretation. Almost
|
| - * certainly it will fail the tests below.
|
| - */
|
| - (void)png_icc_profile_error(png_ptr, NULL, name, temp,
|
| - "unexpected NamedColor ICC profile class");
|
| - break;
|
| -
|
| - default:
|
| - /* To allow for future enhancements to the profile accept unrecognized
|
| - * profile classes with a warning, these then hit the test below on the
|
| - * tag content to ensure they are backward compatible with one of the
|
| - * understood profiles.
|
| - */
|
| - (void)png_icc_profile_error(png_ptr, NULL, name, temp,
|
| - "unrecognized ICC profile class");
|
| - break;
|
| - }
|
| -
|
| - /* For any profile other than a device link one the PCS must be encoded
|
| - * either in XYZ or Lab.
|
| - */
|
| - temp = png_get_uint_32(profile+20);
|
| - switch (temp)
|
| - {
|
| - case 0x58595A20: /* 'XYZ ' */
|
| - case 0x4C616220: /* 'Lab ' */
|
| - break;
|
| -
|
| - default:
|
| - return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| - "unexpected ICC PCS encoding");
|
| - }
|
| -
|
| - return 1;
|
| -}
|
| -
|
| -int /* PRIVATE */
|
| -png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| - png_const_charp name, png_uint_32 profile_length,
|
| - png_const_bytep profile /* header plus whole tag table */)
|
| -{
|
| - png_uint_32 tag_count = png_get_uint_32(profile+128);
|
| - png_uint_32 itag;
|
| - png_const_bytep tag = profile+132; /* The first tag */
|
| -
|
| - /* First scan all the tags in the table and add bits to the icc_info value
|
| - * (temporarily in 'tags').
|
| - */
|
| - for (itag=0; itag < tag_count; ++itag, tag += 12)
|
| - {
|
| - png_uint_32 tag_id = png_get_uint_32(tag+0);
|
| - png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */
|
| - png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */
|
| -
|
| - /* The ICC specification does not exclude zero length tags, therefore the
|
| - * start might actually be anywhere if there is no data, but this would be
|
| - * a clear abuse of the intent of the standard so the start is checked for
|
| - * being in range. All defined tag types have an 8 byte header - a 4 byte
|
| - * type signature then 0.
|
| - */
|
| - if ((tag_start & 3) != 0)
|
| - {
|
| - /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is
|
| - * only a warning here because libpng does not care about the
|
| - * alignment.
|
| - */
|
| - (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
|
| - "ICC profile tag start not a multiple of 4");
|
| - }
|
| -
|
| - /* This is a hard error; potentially it can cause read outside the
|
| - * profile.
|
| - */
|
| - if (tag_start > profile_length || tag_length > profile_length - tag_start)
|
| - return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
|
| - "ICC profile tag outside profile");
|
| - }
|
| -
|
| - return 1; /* success, maybe with warnings */
|
| -}
|
| -
|
| -#ifdef PNG_sRGB_SUPPORTED
|
| -/* Information about the known ICC sRGB profiles */
|
| -static const struct
|
| -{
|
| - png_uint_32 adler, crc, length;
|
| - png_uint_32 md5[4];
|
| - png_byte have_md5;
|
| - png_byte is_broken;
|
| - png_uint_16 intent;
|
| -
|
| -# define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0)
|
| -# define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\
|
| - { adler, crc, length, md5, broke, intent },
|
| -
|
| -} png_sRGB_checks[] =
|
| -{
|
| - /* This data comes from contrib/tools/checksum-icc run on downloads of
|
| - * all four ICC sRGB profiles from www.color.org.
|
| - */
|
| - /* adler32, crc32, MD5[4], intent, date, length, file-name */
|
| - PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9,
|
| - PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0,
|
| - "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc")
|
| -
|
| - /* ICC sRGB v2 perceptual no black-compensation: */
|
| - PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21,
|
| - PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0,
|
| - "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc")
|
| -
|
| - PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae,
|
| - PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0,
|
| - "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc")
|
| -
|
| - /* ICC sRGB v4 perceptual */
|
| - PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812,
|
| - PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0,
|
| - "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc")
|
| -
|
| - /* The following profiles have no known MD5 checksum. If there is a match
|
| - * on the (empty) MD5 the other fields are used to attempt a match and
|
| - * a warning is produced. The first two of these profiles have a 'cprt' tag
|
| - * which suggests that they were also made by Hewlett Packard.
|
| - */
|
| - PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce,
|
| - PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0,
|
| - "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc")
|
| -
|
| - /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not
|
| - * match the D50 PCS illuminant in the header (it is in fact the D65 values,
|
| - * so the white point is recorded as the un-adapted value.) The profiles
|
| - * below only differ in one byte - the intent - and are basically the same as
|
| - * the previous profile except for the mediaWhitePointTag error and a missing
|
| - * chromaticAdaptationTag.
|
| - */
|
| - PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552,
|
| - PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/,
|
| - "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual")
|
| -
|
| - PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d,
|
| - PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/,
|
| - "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative")
|
| -};
|
| -
|
| -static int
|
| -png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
|
| - png_const_bytep profile, uLong adler)
|
| -{
|
| - /* The quick check is to verify just the MD5 signature and trust the
|
| - * rest of the data. Because the profile has already been verified for
|
| - * correctness this is safe. png_colorspace_set_sRGB will check the 'intent'
|
| - * field too, so if the profile has been edited with an intent not defined
|
| - * by sRGB (but maybe defined by a later ICC specification) the read of
|
| - * the profile will fail at that point.
|
| - */
|
| - png_uint_32 length = 0;
|
| - png_uint_32 intent = 0x10000; /* invalid */
|
| -#if PNG_sRGB_PROFILE_CHECKS > 1
|
| - uLong crc = 0; /* the value for 0 length data */
|
| -#endif
|
| - unsigned int i;
|
| -
|
| - for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
|
| - {
|
| - if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
|
| - png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] &&
|
| - png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] &&
|
| - png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3])
|
| - {
|
| - /* This may be one of the old HP profiles without an MD5, in that
|
| - * case we can only use the length and Adler32 (note that these
|
| - * are not used by default if there is an MD5!)
|
| - */
|
| -# if PNG_sRGB_PROFILE_CHECKS == 0
|
| - if (png_sRGB_checks[i].have_md5)
|
| - return 1+png_sRGB_checks[i].is_broken;
|
| -# endif
|
| -
|
| - /* Profile is unsigned or more checks have been configured in. */
|
| - if (length == 0)
|
| - {
|
| - length = png_get_uint_32(profile);
|
| - intent = png_get_uint_32(profile+64);
|
| - }
|
| -
|
| - /* Length *and* intent must match */
|
| - if (length == png_sRGB_checks[i].length &&
|
| - intent == png_sRGB_checks[i].intent)
|
| - {
|
| - /* Now calculate the adler32 if not done already. */
|
| - if (adler == 0)
|
| - {
|
| - adler = adler32(0, NULL, 0);
|
| - adler = adler32(adler, profile, length);
|
| - }
|
| -
|
| - if (adler == png_sRGB_checks[i].adler)
|
| - {
|
| - /* These basic checks suggest that the data has not been
|
| - * modified, but if the check level is more than 1 perform
|
| - * our own crc32 checksum on the data.
|
| - */
|
| -# if PNG_sRGB_PROFILE_CHECKS > 1
|
| - if (crc == 0)
|
| - {
|
| - crc = crc32(0, NULL, 0);
|
| - crc = crc32(crc, profile, length);
|
| - }
|
| -
|
| - /* So this check must pass for the 'return' below to happen.
|
| - */
|
| - if (crc == png_sRGB_checks[i].crc)
|
| -# endif
|
| - {
|
| - if (png_sRGB_checks[i].is_broken)
|
| - {
|
| - /* These profiles are known to have bad data that may cause
|
| - * problems if they are used, therefore attempt to
|
| - * discourage their use, skip the 'have_md5' warning below,
|
| - * which is made irrelevant by this error.
|
| - */
|
| - png_chunk_report(png_ptr, "known incorrect sRGB profile",
|
| - PNG_CHUNK_ERROR);
|
| - }
|
| -
|
| - /* Warn that this being done; this isn't even an error since
|
| - * the profile is perfectly valid, but it would be nice if
|
| - * people used the up-to-date ones.
|
| - */
|
| - else if (!png_sRGB_checks[i].have_md5)
|
| - {
|
| - png_chunk_report(png_ptr,
|
| - "out-of-date sRGB profile with no signature",
|
| - PNG_CHUNK_WARNING);
|
| - }
|
| -
|
| - return 1+png_sRGB_checks[i].is_broken;
|
| - }
|
| - }
|
| - }
|
| -
|
| -# if PNG_sRGB_PROFILE_CHECKS > 0
|
| - /* The signature matched, but the profile had been changed in some
|
| - * way. This is an apparent violation of the ICC terms of use and,
|
| - * anyway, probably indicates a data error or uninformed hacking.
|
| - */
|
| - if (png_sRGB_checks[i].have_md5)
|
| - png_benign_error(png_ptr,
|
| - "copyright violation: edited ICC profile ignored");
|
| -# endif
|
| - }
|
| - }
|
| -
|
| - return 0; /* no match */
|
| -}
|
| -#endif
|
| -
|
| -#ifdef PNG_sRGB_SUPPORTED
|
| -void /* PRIVATE */
|
| -png_icc_set_sRGB(png_const_structrp png_ptr,
|
| - png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
|
| -{
|
| - /* Is this profile one of the known ICC sRGB profiles? If it is, just set
|
| - * the sRGB information.
|
| - */
|
| - if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler))
|
| - (void)png_colorspace_set_sRGB(png_ptr, colorspace,
|
| - (int)/*already checked*/png_get_uint_32(profile+64));
|
| -}
|
| -#endif /* PNG_READ_sRGB_SUPPORTED */
|
| -
|
| -int /* PRIVATE */
|
| -png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| - png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
|
| - int color_type)
|
| -{
|
| - if (colorspace->flags & PNG_COLORSPACE_INVALID)
|
| - return 0;
|
| -
|
| - if (png_icc_check_length(png_ptr, colorspace, name, profile_length) &&
|
| - png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
|
| - color_type) &&
|
| - png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
|
| - profile))
|
| - {
|
| -# ifdef PNG_sRGB_SUPPORTED
|
| - /* If no sRGB support, don't try storing sRGB information */
|
| - png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
|
| -# endif
|
| - return 1;
|
| - }
|
| -
|
| - /* Failure case */
|
| - return 0;
|
| -}
|
| -#endif /* iCCP */
|
| -
|
| -#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
| -void /* PRIVATE */
|
| -png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
|
| -{
|
| - /* Set the rgb_to_gray coefficients from the colorspace. */
|
| - if (!png_ptr->rgb_to_gray_coefficients_set &&
|
| - (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
|
| - {
|
| - /* png_set_background has not been called, get the coefficients from the Y
|
| - * values of the colorspace colorants.
|
| - */
|
| - png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y;
|
| - png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y;
|
| - png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y;
|
| - png_fixed_point total = r+g+b;
|
| -
|
| - if (total > 0 &&
|
| - r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 &&
|
| - g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 &&
|
| - b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 &&
|
| - r+g+b <= 32769)
|
| - {
|
| - /* We allow 0 coefficients here. r+g+b may be 32769 if two or
|
| - * all of the coefficients were rounded up. Handle this by
|
| - * reducing the *largest* coefficient by 1; this matches the
|
| - * approach used for the default coefficients in pngrtran.c
|
| - */
|
| - int add = 0;
|
| -
|
| - if (r+g+b > 32768)
|
| - add = -1;
|
| - else if (r+g+b < 32768)
|
| - add = 1;
|
| -
|
| - if (add != 0)
|
| - {
|
| - if (g >= r && g >= b)
|
| - g += add;
|
| - else if (r >= g && r >= b)
|
| - r += add;
|
| - else
|
| - b += add;
|
| - }
|
| -
|
| - /* Check for an internal error. */
|
| - if (r+g+b != 32768)
|
| - png_error(png_ptr,
|
| - "internal error handling cHRM coefficients");
|
| -
|
| - else
|
| - {
|
| - png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
|
| - png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
|
| - }
|
| - }
|
| -
|
| - /* This is a png_error at present even though it could be ignored -
|
| - * it should never happen, but it is important that if it does, the
|
| - * bug is fixed.
|
| - */
|
| - else
|
| - png_error(png_ptr, "internal error handling cHRM->XYZ");
|
| - }
|
| -}
|
| -#endif
|
| -
|
| -#endif /* COLORSPACE */
|
| -
|
| -void /* PRIVATE */
|
| -png_check_IHDR(png_const_structrp png_ptr,
|
| - png_uint_32 width, png_uint_32 height, int bit_depth,
|
| - int color_type, int interlace_type, int compression_type,
|
| - int filter_type)
|
| -{
|
| - int error = 0;
|
| -
|
| - /* Check for width and height valid values */
|
| - if (width == 0)
|
| - {
|
| - png_warning(png_ptr, "Image width is zero in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (height == 0)
|
| - {
|
| - png_warning(png_ptr, "Image height is zero in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| -# ifdef PNG_SET_USER_LIMITS_SUPPORTED
|
| - if (width > png_ptr->user_width_max)
|
| -
|
| -# else
|
| - if (width > PNG_USER_WIDTH_MAX)
|
| -# endif
|
| - {
|
| - png_warning(png_ptr, "Image width exceeds user limit in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| -# ifdef PNG_SET_USER_LIMITS_SUPPORTED
|
| - if (height > png_ptr->user_height_max)
|
| -# else
|
| - if (height > PNG_USER_HEIGHT_MAX)
|
| -# endif
|
| - {
|
| - png_warning(png_ptr, "Image height exceeds user limit in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (width > PNG_UINT_31_MAX)
|
| - {
|
| - png_warning(png_ptr, "Invalid image width in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (height > PNG_UINT_31_MAX)
|
| - {
|
| - png_warning(png_ptr, "Invalid image height in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (width > (PNG_UINT_32_MAX
|
| - >> 3) /* 8-byte RGBA pixels */
|
| - - 48 /* bigrowbuf hack */
|
| - - 1 /* filter byte */
|
| - - 7*8 /* rounding of width to multiple of 8 pixels */
|
| - - 8) /* extra max_pixel_depth pad */
|
| - png_warning(png_ptr, "Width is too large for libpng to process pixels");
|
| -
|
| - /* Check other values */
|
| - if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
|
| - bit_depth != 8 && bit_depth != 16)
|
| - {
|
| - png_warning(png_ptr, "Invalid bit depth in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (color_type < 0 || color_type == 1 ||
|
| - color_type == 5 || color_type > 6)
|
| - {
|
| - png_warning(png_ptr, "Invalid color type in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
|
| - ((color_type == PNG_COLOR_TYPE_RGB ||
|
| - color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
|
| - color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
|
| - {
|
| - png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (interlace_type >= PNG_INTERLACE_LAST)
|
| - {
|
| - png_warning(png_ptr, "Unknown interlace method in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (compression_type != PNG_COMPRESSION_TYPE_BASE)
|
| - {
|
| - png_warning(png_ptr, "Unknown compression method in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| -# ifdef PNG_MNG_FEATURES_SUPPORTED
|
| - /* Accept filter_method 64 (intrapixel differencing) only if
|
| - * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
|
| - * 2. Libpng did not read a PNG signature (this filter_method is only
|
| - * used in PNG datastreams that are embedded in MNG datastreams) and
|
| - * 3. The application called png_permit_mng_features with a mask that
|
| - * included PNG_FLAG_MNG_FILTER_64 and
|
| - * 4. The filter_method is 64 and
|
| - * 5. The color_type is RGB or RGBA
|
| - */
|
| - if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) &&
|
| - png_ptr->mng_features_permitted)
|
| - png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
|
| -
|
| - if (filter_type != PNG_FILTER_TYPE_BASE)
|
| - {
|
| - if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
|
| - (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
|
| - ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
|
| - (color_type == PNG_COLOR_TYPE_RGB ||
|
| - color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
|
| - {
|
| - png_warning(png_ptr, "Unknown filter method in IHDR");
|
| - error = 1;
|
| - }
|
| -
|
| - if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE)
|
| - {
|
| - png_warning(png_ptr, "Invalid filter method in IHDR");
|
| - error = 1;
|
| - }
|
| - }
|
| -
|
| -# else
|
| - if (filter_type != PNG_FILTER_TYPE_BASE)
|
| - {
|
| - png_warning(png_ptr, "Unknown filter method in IHDR");
|
| - error = 1;
|
| - }
|
| -# endif
|
| -
|
| - if (error == 1)
|
| - png_error(png_ptr, "Invalid IHDR data");
|
| -}
|
| -
|
| -#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
|
| -/* ASCII to fp functions */
|
| -/* Check an ASCII formated floating point value, see the more detailed
|
| - * comments in pngpriv.h
|
| - */
|
| -/* The following is used internally to preserve the sticky flags */
|
| -#define png_fp_add(state, flags) ((state) |= (flags))
|
| -#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
|
| -
|
| -int /* PRIVATE */
|
| -png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
|
| - png_size_tp whereami)
|
| -{
|
| - int state = *statep;
|
| - png_size_t i = *whereami;
|
| -
|
| - while (i < size)
|
| - {
|
| - int type;
|
| - /* First find the type of the next character */
|
| - switch (string[i])
|
| - {
|
| - case 43: type = PNG_FP_SAW_SIGN; break;
|
| - case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
|
| - case 46: type = PNG_FP_SAW_DOT; break;
|
| - case 48: type = PNG_FP_SAW_DIGIT; break;
|
| - case 49: case 50: case 51: case 52:
|
| - case 53: case 54: case 55: case 56:
|
| - case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
|
| - case 69:
|
| - case 101: type = PNG_FP_SAW_E; break;
|
| - default: goto PNG_FP_End;
|
| - }
|
| -
|
| - /* Now deal with this type according to the current
|
| - * state, the type is arranged to not overlap the
|
| - * bits of the PNG_FP_STATE.
|
| - */
|
| - switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
|
| - {
|
| - case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
|
| - if (state & PNG_FP_SAW_ANY)
|
| - goto PNG_FP_End; /* not a part of the number */
|
| -
|
| - png_fp_add(state, type);
|
| - break;
|
| -
|
| - case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
|
| - /* Ok as trailer, ok as lead of fraction. */
|
| - if (state & PNG_FP_SAW_DOT) /* two dots */
|
| - goto PNG_FP_End;
|
| -
|
| - else if (state & PNG_FP_SAW_DIGIT) /* trailing dot? */
|
| - png_fp_add(state, type);
|
| -
|
| - else
|
| - png_fp_set(state, PNG_FP_FRACTION | type);
|
| -
|
| - break;
|
| -
|
| - case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
|
| - if (state & PNG_FP_SAW_DOT) /* delayed fraction */
|
| - png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
|
| -
|
| - png_fp_add(state, type | PNG_FP_WAS_VALID);
|
| -
|
| - break;
|
| -
|
| - case PNG_FP_INTEGER + PNG_FP_SAW_E:
|
| - if ((state & PNG_FP_SAW_DIGIT) == 0)
|
| - goto PNG_FP_End;
|
| -
|
| - png_fp_set(state, PNG_FP_EXPONENT);
|
| -
|
| - break;
|
| -
|
| - /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
|
| - goto PNG_FP_End; ** no sign in fraction */
|
| -
|
| - /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
|
| - goto PNG_FP_End; ** Because SAW_DOT is always set */
|
| -
|
| - case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
|
| - png_fp_add(state, type | PNG_FP_WAS_VALID);
|
| - break;
|
| -
|
| - case PNG_FP_FRACTION + PNG_FP_SAW_E:
|
| - /* This is correct because the trailing '.' on an
|
| - * integer is handled above - so we can only get here
|
| - * with the sequence ".E" (with no preceding digits).
|
| - */
|
| - if ((state & PNG_FP_SAW_DIGIT) == 0)
|
| - goto PNG_FP_End;
|
| -
|
| - png_fp_set(state, PNG_FP_EXPONENT);
|
| -
|
| - break;
|
| -
|
| - case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
|
| - if (state & PNG_FP_SAW_ANY)
|
| - goto PNG_FP_End; /* not a part of the number */
|
| -
|
| - png_fp_add(state, PNG_FP_SAW_SIGN);
|
| -
|
| - break;
|
| -
|
| - /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
|
| - goto PNG_FP_End; */
|
| -
|
| - case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
|
| - png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
|
| -
|
| - break;
|
| -
|
| - /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
|
| - goto PNG_FP_End; */
|
| -
|
| - default: goto PNG_FP_End; /* I.e. break 2 */
|
| - }
|
| -
|
| - /* The character seems ok, continue. */
|
| - ++i;
|
| - }
|
| -
|
| -PNG_FP_End:
|
| - /* Here at the end, update the state and return the correct
|
| - * return code.
|
| - */
|
| - *statep = state;
|
| - *whereami = i;
|
| -
|
| - return (state & PNG_FP_SAW_DIGIT) != 0;
|
| -}
|
| -
|
| -
|
| -/* The same but for a complete string. */
|
| -int
|
| -png_check_fp_string(png_const_charp string, png_size_t size)
|
| -{
|
| - int state=0;
|
| - png_size_t char_index=0;
|
| -
|
| - if (png_check_fp_number(string, size, &state, &char_index) &&
|
| - (char_index == size || string[char_index] == 0))
|
| - return state /* must be non-zero - see above */;
|
| -
|
| - return 0; /* i.e. fail */
|
| -}
|
| -#endif /* pCAL or sCAL */
|
| -
|
| -#ifdef PNG_sCAL_SUPPORTED
|
| -# ifdef PNG_FLOATING_POINT_SUPPORTED
|
| -/* Utility used below - a simple accurate power of ten from an integral
|
| - * exponent.
|
| - */
|
| -static double
|
| -png_pow10(int power)
|
| -{
|
| - int recip = 0;
|
| - double d = 1;
|
| -
|
| - /* Handle negative exponent with a reciprocal at the end because
|
| - * 10 is exact whereas .1 is inexact in base 2
|
| - */
|
| - if (power < 0)
|
| - {
|
| - if (power < DBL_MIN_10_EXP) return 0;
|
| - recip = 1, power = -power;
|
| - }
|
| -
|
| - if (power > 0)
|
| - {
|
| - /* Decompose power bitwise. */
|
| - double mult = 10;
|
| - do
|
| - {
|
| - if (power & 1) d *= mult;
|
| - mult *= mult;
|
| - power >>= 1;
|
| - }
|
| - while (power > 0);
|
| -
|
| - if (recip) d = 1/d;
|
| - }
|
| - /* else power is 0 and d is 1 */
|
| -
|
| - return d;
|
| -}
|
| -
|
| -/* Function to format a floating point value in ASCII with a given
|
| - * precision.
|
| - */
|
| -void /* PRIVATE */
|
| -png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
|
| - double fp, unsigned int precision)
|
| -{
|
| - /* We use standard functions from math.h, but not printf because
|
| - * that would require stdio. The caller must supply a buffer of
|
| - * sufficient size or we will png_error. The tests on size and
|
| - * the space in ascii[] consumed are indicated below.
|
| - */
|
| - if (precision < 1)
|
| - precision = DBL_DIG;
|
| -
|
| - /* Enforce the limit of the implementation precision too. */
|
| - if (precision > DBL_DIG+1)
|
| - precision = DBL_DIG+1;
|
| -
|
| - /* Basic sanity checks */
|
| - if (size >= precision+5) /* See the requirements below. */
|
| - {
|
| - if (fp < 0)
|
| - {
|
| - fp = -fp;
|
| - *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */
|
| - --size;
|
| - }
|
| -
|
| - if (fp >= DBL_MIN && fp <= DBL_MAX)
|
| - {
|
| - int exp_b10; /* A base 10 exponent */
|
| - double base; /* 10^exp_b10 */
|
| -
|
| - /* First extract a base 10 exponent of the number,
|
| - * the calculation below rounds down when converting
|
| - * from base 2 to base 10 (multiply by log10(2) -
|
| - * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
|
| - * be increased. Note that the arithmetic shift
|
| - * performs a floor() unlike C arithmetic - using a
|
| - * C multiply would break the following for negative
|
| - * exponents.
|
| - */
|
| - (void)frexp(fp, &exp_b10); /* exponent to base 2 */
|
| -
|
| - exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
|
| -
|
| - /* Avoid underflow here. */
|
| - base = png_pow10(exp_b10); /* May underflow */
|
| -
|
| - while (base < DBL_MIN || base < fp)
|
| - {
|
| - /* And this may overflow. */
|
| - double test = png_pow10(exp_b10+1);
|
| -
|
| - if (test <= DBL_MAX)
|
| - ++exp_b10, base = test;
|
| -
|
| - else
|
| - break;
|
| - }
|
| -
|
| - /* Normalize fp and correct exp_b10, after this fp is in the
|
| - * range [.1,1) and exp_b10 is both the exponent and the digit
|
| - * *before* which the decimal point should be inserted
|
| - * (starting with 0 for the first digit). Note that this
|
| - * works even if 10^exp_b10 is out of range because of the
|
| - * test on DBL_MAX above.
|
| - */
|
| - fp /= base;
|
| - while (fp >= 1) fp /= 10, ++exp_b10;
|
| -
|
| - /* Because of the code above fp may, at this point, be
|
| - * less than .1, this is ok because the code below can
|
| - * handle the leading zeros this generates, so no attempt
|
| - * is made to correct that here.
|
| - */
|
| -
|
| - {
|
| - int czero, clead, cdigits;
|
| - char exponent[10];
|
| -
|
| - /* Allow up to two leading zeros - this will not lengthen
|
| - * the number compared to using E-n.
|
| - */
|
| - if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
|
| - {
|
| - czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */
|
| - exp_b10 = 0; /* Dot added below before first output. */
|
| - }
|
| - else
|
| - czero = 0; /* No zeros to add */
|
| -
|
| - /* Generate the digit list, stripping trailing zeros and
|
| - * inserting a '.' before a digit if the exponent is 0.
|
| - */
|
| - clead = czero; /* Count of leading zeros */
|
| - cdigits = 0; /* Count of digits in list. */
|
| -
|
| - do
|
| - {
|
| - double d;
|
| -
|
| - fp *= 10;
|
| - /* Use modf here, not floor and subtract, so that
|
| - * the separation is done in one step. At the end
|
| - * of the loop don't break the number into parts so
|
| - * that the final digit is rounded.
|
| - */
|
| - if (cdigits+czero-clead+1 < (int)precision)
|
| - fp = modf(fp, &d);
|
| -
|
| - else
|
| - {
|
| - d = floor(fp + .5);
|
| -
|
| - if (d > 9)
|
| - {
|
| - /* Rounding up to 10, handle that here. */
|
| - if (czero > 0)
|
| - {
|
| - --czero, d = 1;
|
| - if (cdigits == 0) --clead;
|
| - }
|
| - else
|
| - {
|
| - while (cdigits > 0 && d > 9)
|
| - {
|
| - int ch = *--ascii;
|
| -
|
| - if (exp_b10 != (-1))
|
| - ++exp_b10;
|
| -
|
| - else if (ch == 46)
|
| - {
|
| - ch = *--ascii, ++size;
|
| - /* Advance exp_b10 to '1', so that the
|
| - * decimal point happens after the
|
| - * previous digit.
|
| - */
|
| - exp_b10 = 1;
|
| - }
|
| -
|
| - --cdigits;
|
| - d = ch - 47; /* I.e. 1+(ch-48) */
|
| - }
|
| -
|
| - /* Did we reach the beginning? If so adjust the
|
| - * exponent but take into account the leading
|
| - * decimal point.
|
| - */
|
| - if (d > 9) /* cdigits == 0 */
|
| - {
|
| - if (exp_b10 == (-1))
|
| - {
|
| - /* Leading decimal point (plus zeros?), if
|
| - * we lose the decimal point here it must
|
| - * be reentered below.
|
| - */
|
| - int ch = *--ascii;
|
| -
|
| - if (ch == 46)
|
| - ++size, exp_b10 = 1;
|
| -
|
| - /* Else lost a leading zero, so 'exp_b10' is
|
| - * still ok at (-1)
|
| - */
|
| - }
|
| - else
|
| - ++exp_b10;
|
| -
|
| - /* In all cases we output a '1' */
|
| - d = 1;
|
| - }
|
| - }
|
| - }
|
| - fp = 0; /* Guarantees termination below. */
|
| - }
|
| -
|
| - if (d == 0)
|
| - {
|
| - ++czero;
|
| - if (cdigits == 0) ++clead;
|
| - }
|
| - else
|
| - {
|
| - /* Included embedded zeros in the digit count. */
|
| - cdigits += czero - clead;
|
| - clead = 0;
|
| -
|
| - while (czero > 0)
|
| - {
|
| - /* exp_b10 == (-1) means we just output the decimal
|
| - * place - after the DP don't adjust 'exp_b10' any
|
| - * more!
|
| - */
|
| - if (exp_b10 != (-1))
|
| - {
|
| - if (exp_b10 == 0) *ascii++ = 46, --size;
|
| - /* PLUS 1: TOTAL 4 */
|
| - --exp_b10;
|
| - }
|
| - *ascii++ = 48, --czero;
|
| - }
|
| -
|
| - if (exp_b10 != (-1))
|
| - {
|
| - if (exp_b10 == 0) *ascii++ = 46, --size; /* counted
|
| - above */
|
| - --exp_b10;
|
| - }
|
| - *ascii++ = (char)(48 + (int)d), ++cdigits;
|
| - }
|
| - }
|
| - while (cdigits+czero-clead < (int)precision && fp > DBL_MIN);
|
| -
|
| - /* The total output count (max) is now 4+precision */
|
| -
|
| - /* Check for an exponent, if we don't need one we are
|
| - * done and just need to terminate the string. At
|
| - * this point exp_b10==(-1) is effectively if flag - it got
|
| - * to '-1' because of the decrement after outputing
|
| - * the decimal point above (the exponent required is
|
| - * *not* -1!)
|
| - */
|
| - if (exp_b10 >= (-1) && exp_b10 <= 2)
|
| - {
|
| - /* The following only happens if we didn't output the
|
| - * leading zeros above for negative exponent, so this
|
| - * doest add to the digit requirement. Note that the
|
| - * two zeros here can only be output if the two leading
|
| - * zeros were *not* output, so this doesn't increase
|
| - * the output count.
|
| - */
|
| - while (--exp_b10 >= 0) *ascii++ = 48;
|
| -
|
| - *ascii = 0;
|
| -
|
| - /* Total buffer requirement (including the '\0') is
|
| - * 5+precision - see check at the start.
|
| - */
|
| - return;
|
| - }
|
| -
|
| - /* Here if an exponent is required, adjust size for
|
| - * the digits we output but did not count. The total
|
| - * digit output here so far is at most 1+precision - no
|
| - * decimal point and no leading or trailing zeros have
|
| - * been output.
|
| - */
|
| - size -= cdigits;
|
| -
|
| - *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */
|
| -
|
| - /* The following use of an unsigned temporary avoids ambiguities in
|
| - * the signed arithmetic on exp_b10 and permits GCC at least to do
|
| - * better optimization.
|
| - */
|
| - {
|
| - unsigned int uexp_b10;
|
| -
|
| - if (exp_b10 < 0)
|
| - {
|
| - *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
|
| - uexp_b10 = -exp_b10;
|
| - }
|
| -
|
| - else
|
| - uexp_b10 = exp_b10;
|
| -
|
| - cdigits = 0;
|
| -
|
| - while (uexp_b10 > 0)
|
| - {
|
| - exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
|
| - uexp_b10 /= 10;
|
| - }
|
| - }
|
| -
|
| - /* Need another size check here for the exponent digits, so
|
| - * this need not be considered above.
|
| - */
|
| - if ((int)size > cdigits)
|
| - {
|
| - while (cdigits > 0) *ascii++ = exponent[--cdigits];
|
| -
|
| - *ascii = 0;
|
| -
|
| - return;
|
| - }
|
| - }
|
| - }
|
| - else if (!(fp >= DBL_MIN))
|
| - {
|
| - *ascii++ = 48; /* '0' */
|
| - *ascii = 0;
|
| - return;
|
| - }
|
| - else
|
| - {
|
| - *ascii++ = 105; /* 'i' */
|
| - *ascii++ = 110; /* 'n' */
|
| - *ascii++ = 102; /* 'f' */
|
| - *ascii = 0;
|
| - return;
|
| - }
|
| - }
|
| -
|
| - /* Here on buffer too small. */
|
| - png_error(png_ptr, "ASCII conversion buffer too small");
|
| -}
|
| -
|
| -# endif /* FLOATING_POINT */
|
| -
|
| -# ifdef PNG_FIXED_POINT_SUPPORTED
|
| -/* Function to format a fixed point value in ASCII.
|
| - */
|
| -void /* PRIVATE */
|
| -png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
|
| - png_size_t size, png_fixed_point fp)
|
| -{
|
| - /* Require space for 10 decimal digits, a decimal point, a minus sign and a
|
| - * trailing \0, 13 characters:
|
| - */
|
| - if (size > 12)
|
| - {
|
| - png_uint_32 num;
|
| -
|
| - /* Avoid overflow here on the minimum integer. */
|
| - if (fp < 0)
|
| - *ascii++ = 45, --size, num = -fp;
|
| - else
|
| - num = fp;
|
| -
|
| - if (num <= 0x80000000) /* else overflowed */
|
| - {
|
| - unsigned int ndigits = 0, first = 16 /* flag value */;
|
| - char digits[10];
|
| -
|
| - while (num)
|
| - {
|
| - /* Split the low digit off num: */
|
| - unsigned int tmp = num/10;
|
| - num -= tmp*10;
|
| - digits[ndigits++] = (char)(48 + num);
|
| - /* Record the first non-zero digit, note that this is a number
|
| - * starting at 1, it's not actually the array index.
|
| - */
|
| - if (first == 16 && num > 0)
|
| - first = ndigits;
|
| - num = tmp;
|
| - }
|
| -
|
| - if (ndigits > 0)
|
| - {
|
| - while (ndigits > 5) *ascii++ = digits[--ndigits];
|
| - /* The remaining digits are fractional digits, ndigits is '5' or
|
| - * smaller at this point. It is certainly not zero. Check for a
|
| - * non-zero fractional digit:
|
| - */
|
| - if (first <= 5)
|
| - {
|
| - unsigned int i;
|
| - *ascii++ = 46; /* decimal point */
|
| - /* ndigits may be <5 for small numbers, output leading zeros
|
| - * then ndigits digits to first:
|
| - */
|
| - i = 5;
|
| - while (ndigits < i) *ascii++ = 48, --i;
|
| - while (ndigits >= first) *ascii++ = digits[--ndigits];
|
| - /* Don't output the trailing zeros! */
|
| - }
|
| - }
|
| - else
|
| - *ascii++ = 48;
|
| -
|
| - /* And null terminate the string: */
|
| - *ascii = 0;
|
| - return;
|
| - }
|
| - }
|
| -
|
| - /* Here on buffer too small. */
|
| - png_error(png_ptr, "ASCII conversion buffer too small");
|
| -}
|
| -# endif /* FIXED_POINT */
|
| -#endif /* READ_SCAL */
|
| -
|
| -#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
|
| - !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
|
| - (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
|
| - defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| - defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
|
| - (defined(PNG_sCAL_SUPPORTED) && \
|
| - defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
|
| -png_fixed_point
|
| -png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
|
| -{
|
| - double r = floor(100000 * fp + .5);
|
| -
|
| - if (r > 2147483647. || r < -2147483648.)
|
| - png_fixed_error(png_ptr, text);
|
| -
|
| - return (png_fixed_point)r;
|
| -}
|
| -#endif
|
| -
|
| -#if defined(PNG_READ_GAMMA_SUPPORTED) || \
|
| - defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
|
| -/* muldiv functions */
|
| -/* This API takes signed arguments and rounds the result to the nearest
|
| - * integer (or, for a fixed point number - the standard argument - to
|
| - * the nearest .00001). Overflow and divide by zero are signalled in
|
| - * the result, a boolean - true on success, false on overflow.
|
| - */
|
| -int
|
| -png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
|
| - png_int_32 divisor)
|
| -{
|
| - /* Return a * times / divisor, rounded. */
|
| - if (divisor != 0)
|
| - {
|
| - if (a == 0 || times == 0)
|
| - {
|
| - *res = 0;
|
| - return 1;
|
| - }
|
| - else
|
| - {
|
| -#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - double r = a;
|
| - r *= times;
|
| - r /= divisor;
|
| - r = floor(r+.5);
|
| -
|
| - /* A png_fixed_point is a 32-bit integer. */
|
| - if (r <= 2147483647. && r >= -2147483648.)
|
| - {
|
| - *res = (png_fixed_point)r;
|
| - return 1;
|
| - }
|
| -#else
|
| - int negative = 0;
|
| - png_uint_32 A, T, D;
|
| - png_uint_32 s16, s32, s00;
|
| -
|
| - if (a < 0)
|
| - negative = 1, A = -a;
|
| - else
|
| - A = a;
|
| -
|
| - if (times < 0)
|
| - negative = !negative, T = -times;
|
| - else
|
| - T = times;
|
| -
|
| - if (divisor < 0)
|
| - negative = !negative, D = -divisor;
|
| - else
|
| - D = divisor;
|
| -
|
| - /* Following can't overflow because the arguments only
|
| - * have 31 bits each, however the result may be 32 bits.
|
| - */
|
| - s16 = (A >> 16) * (T & 0xffff) +
|
| - (A & 0xffff) * (T >> 16);
|
| - /* Can't overflow because the a*times bit is only 30
|
| - * bits at most.
|
| - */
|
| - s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
|
| - s00 = (A & 0xffff) * (T & 0xffff);
|
| -
|
| - s16 = (s16 & 0xffff) << 16;
|
| - s00 += s16;
|
| -
|
| - if (s00 < s16)
|
| - ++s32; /* carry */
|
| -
|
| - if (s32 < D) /* else overflow */
|
| - {
|
| - /* s32.s00 is now the 64-bit product, do a standard
|
| - * division, we know that s32 < D, so the maximum
|
| - * required shift is 31.
|
| - */
|
| - int bitshift = 32;
|
| - png_fixed_point result = 0; /* NOTE: signed */
|
| -
|
| - while (--bitshift >= 0)
|
| - {
|
| - png_uint_32 d32, d00;
|
| -
|
| - if (bitshift > 0)
|
| - d32 = D >> (32-bitshift), d00 = D << bitshift;
|
| -
|
| - else
|
| - d32 = 0, d00 = D;
|
| -
|
| - if (s32 > d32)
|
| - {
|
| - if (s00 < d00) --s32; /* carry */
|
| - s32 -= d32, s00 -= d00, result += 1<<bitshift;
|
| - }
|
| -
|
| - else
|
| - if (s32 == d32 && s00 >= d00)
|
| - s32 = 0, s00 -= d00, result += 1<<bitshift;
|
| - }
|
| -
|
| - /* Handle the rounding. */
|
| - if (s00 >= (D >> 1))
|
| - ++result;
|
| -
|
| - if (negative)
|
| - result = -result;
|
| -
|
| - /* Check for overflow. */
|
| - if ((negative && result <= 0) || (!negative && result >= 0))
|
| - {
|
| - *res = result;
|
| - return 1;
|
| - }
|
| - }
|
| -#endif
|
| - }
|
| - }
|
| -
|
| - return 0;
|
| -}
|
| -#endif /* READ_GAMMA || INCH_CONVERSIONS */
|
| -
|
| -#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
|
| -/* The following is for when the caller doesn't much care about the
|
| - * result.
|
| - */
|
| -png_fixed_point
|
| -png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
|
| - png_int_32 divisor)
|
| -{
|
| - png_fixed_point result;
|
| -
|
| - if (png_muldiv(&result, a, times, divisor))
|
| - return result;
|
| -
|
| - png_warning(png_ptr, "fixed point overflow ignored");
|
| - return 0;
|
| -}
|
| -#endif
|
| -
|
| -#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */
|
| -/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
|
| -png_fixed_point
|
| -png_reciprocal(png_fixed_point a)
|
| -{
|
| -#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - double r = floor(1E10/a+.5);
|
| -
|
| - if (r <= 2147483647. && r >= -2147483648.)
|
| - return (png_fixed_point)r;
|
| -#else
|
| - png_fixed_point res;
|
| -
|
| - if (png_muldiv(&res, 100000, 100000, a))
|
| - return res;
|
| -#endif
|
| -
|
| - return 0; /* error/overflow */
|
| -}
|
| -
|
| -/* This is the shared test on whether a gamma value is 'significant' - whether
|
| - * it is worth doing gamma correction.
|
| - */
|
| -int /* PRIVATE */
|
| -png_gamma_significant(png_fixed_point gamma_val)
|
| -{
|
| - return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
|
| - gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
|
| -}
|
| -#endif
|
| -
|
| -#ifdef PNG_READ_GAMMA_SUPPORTED
|
| -/* A local convenience routine. */
|
| -static png_fixed_point
|
| -png_product2(png_fixed_point a, png_fixed_point b)
|
| -{
|
| - /* The required result is 1/a * 1/b; the following preserves accuracy. */
|
| -#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - double r = a * 1E-5;
|
| - r *= b;
|
| - r = floor(r+.5);
|
| -
|
| - if (r <= 2147483647. && r >= -2147483648.)
|
| - return (png_fixed_point)r;
|
| -#else
|
| - png_fixed_point res;
|
| -
|
| - if (png_muldiv(&res, a, b, 100000))
|
| - return res;
|
| -#endif
|
| -
|
| - return 0; /* overflow */
|
| -}
|
| -
|
| -/* The inverse of the above. */
|
| -png_fixed_point
|
| -png_reciprocal2(png_fixed_point a, png_fixed_point b)
|
| -{
|
| - /* The required result is 1/a * 1/b; the following preserves accuracy. */
|
| -#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - double r = 1E15/a;
|
| - r /= b;
|
| - r = floor(r+.5);
|
| -
|
| - if (r <= 2147483647. && r >= -2147483648.)
|
| - return (png_fixed_point)r;
|
| -#else
|
| - /* This may overflow because the range of png_fixed_point isn't symmetric,
|
| - * but this API is only used for the product of file and screen gamma so it
|
| - * doesn't matter that the smallest number it can produce is 1/21474, not
|
| - * 1/100000
|
| - */
|
| - png_fixed_point res = png_product2(a, b);
|
| -
|
| - if (res != 0)
|
| - return png_reciprocal(res);
|
| -#endif
|
| -
|
| - return 0; /* overflow */
|
| -}
|
| -#endif /* READ_GAMMA */
|
| -
|
| -#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
|
| -#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| -/* Fixed point gamma.
|
| - *
|
| - * The code to calculate the tables used below can be found in the shell script
|
| - * contrib/tools/intgamma.sh
|
| - *
|
| - * To calculate gamma this code implements fast log() and exp() calls using only
|
| - * fixed point arithmetic. This code has sufficient precision for either 8-bit
|
| - * or 16-bit sample values.
|
| - *
|
| - * The tables used here were calculated using simple 'bc' programs, but C double
|
| - * precision floating point arithmetic would work fine.
|
| - *
|
| - * 8-bit log table
|
| - * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
|
| - * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
|
| - * mantissa. The numbers are 32-bit fractions.
|
| - */
|
| -static const png_uint_32
|
| -png_8bit_l2[128] =
|
| -{
|
| - 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
|
| - 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
|
| - 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
|
| - 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
|
| - 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
|
| - 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
|
| - 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
|
| - 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
|
| - 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
|
| - 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
|
| - 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
|
| - 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
|
| - 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
|
| - 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
|
| - 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
|
| - 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
|
| - 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
|
| - 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
|
| - 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
|
| - 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
|
| - 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
|
| - 24347096U, 0U
|
| -
|
| -#if 0
|
| - /* The following are the values for 16-bit tables - these work fine for the
|
| - * 8-bit conversions but produce very slightly larger errors in the 16-bit
|
| - * log (about 1.2 as opposed to 0.7 absolute error in the final value). To
|
| - * use these all the shifts below must be adjusted appropriately.
|
| - */
|
| - 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
|
| - 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
|
| - 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
|
| - 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
|
| - 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
|
| - 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
|
| - 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
|
| - 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
|
| - 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
|
| - 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
|
| - 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
|
| - 1119, 744, 372
|
| -#endif
|
| -};
|
| -
|
| -static png_int_32
|
| -png_log8bit(unsigned int x)
|
| -{
|
| - unsigned int lg2 = 0;
|
| - /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
|
| - * because the log is actually negate that means adding 1. The final
|
| - * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
|
| - * input), return -1 for the overflow (log 0) case, - so the result is
|
| - * always at most 19 bits.
|
| - */
|
| - if ((x &= 0xff) == 0)
|
| - return -1;
|
| -
|
| - if ((x & 0xf0) == 0)
|
| - lg2 = 4, x <<= 4;
|
| -
|
| - if ((x & 0xc0) == 0)
|
| - lg2 += 2, x <<= 2;
|
| -
|
| - if ((x & 0x80) == 0)
|
| - lg2 += 1, x <<= 1;
|
| -
|
| - /* result is at most 19 bits, so this cast is safe: */
|
| - return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
|
| -}
|
| -
|
| -/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
|
| - * for 16-bit images we use the most significant 8 bits of the 16-bit value to
|
| - * get an approximation then multiply the approximation by a correction factor
|
| - * determined by the remaining up to 8 bits. This requires an additional step
|
| - * in the 16-bit case.
|
| - *
|
| - * We want log2(value/65535), we have log2(v'/255), where:
|
| - *
|
| - * value = v' * 256 + v''
|
| - * = v' * f
|
| - *
|
| - * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
|
| - * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
|
| - * than 258. The final factor also needs to correct for the fact that our 8-bit
|
| - * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
|
| - *
|
| - * This gives a final formula using a calculated value 'x' which is value/v' and
|
| - * scaling by 65536 to match the above table:
|
| - *
|
| - * log2(x/257) * 65536
|
| - *
|
| - * Since these numbers are so close to '1' we can use simple linear
|
| - * interpolation between the two end values 256/257 (result -368.61) and 258/257
|
| - * (result 367.179). The values used below are scaled by a further 64 to give
|
| - * 16-bit precision in the interpolation:
|
| - *
|
| - * Start (256): -23591
|
| - * Zero (257): 0
|
| - * End (258): 23499
|
| - */
|
| -static png_int_32
|
| -png_log16bit(png_uint_32 x)
|
| -{
|
| - unsigned int lg2 = 0;
|
| -
|
| - /* As above, but now the input has 16 bits. */
|
| - if ((x &= 0xffff) == 0)
|
| - return -1;
|
| -
|
| - if ((x & 0xff00) == 0)
|
| - lg2 = 8, x <<= 8;
|
| -
|
| - if ((x & 0xf000) == 0)
|
| - lg2 += 4, x <<= 4;
|
| -
|
| - if ((x & 0xc000) == 0)
|
| - lg2 += 2, x <<= 2;
|
| -
|
| - if ((x & 0x8000) == 0)
|
| - lg2 += 1, x <<= 1;
|
| -
|
| - /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
|
| - * value.
|
| - */
|
| - lg2 <<= 28;
|
| - lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
|
| -
|
| - /* Now we need to interpolate the factor, this requires a division by the top
|
| - * 8 bits. Do this with maximum precision.
|
| - */
|
| - x = ((x << 16) + (x >> 9)) / (x >> 8);
|
| -
|
| - /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
|
| - * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
|
| - * 16 bits to interpolate to get the low bits of the result. Round the
|
| - * answer. Note that the end point values are scaled by 64 to retain overall
|
| - * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
|
| - * the overall scaling by 6-12. Round at every step.
|
| - */
|
| - x -= 1U << 24;
|
| -
|
| - if (x <= 65536U) /* <= '257' */
|
| - lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
|
| -
|
| - else
|
| - lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
|
| -
|
| - /* Safe, because the result can't have more than 20 bits: */
|
| - return (png_int_32)((lg2 + 2048) >> 12);
|
| -}
|
| -
|
| -/* The 'exp()' case must invert the above, taking a 20-bit fixed point
|
| - * logarithmic value and returning a 16 or 8-bit number as appropriate. In
|
| - * each case only the low 16 bits are relevant - the fraction - since the
|
| - * integer bits (the top 4) simply determine a shift.
|
| - *
|
| - * The worst case is the 16-bit distinction between 65535 and 65534, this
|
| - * requires perhaps spurious accuracty in the decoding of the logarithm to
|
| - * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
|
| - * of getting this accuracy in practice.
|
| - *
|
| - * To deal with this the following exp() function works out the exponent of the
|
| - * frational part of the logarithm by using an accurate 32-bit value from the
|
| - * top four fractional bits then multiplying in the remaining bits.
|
| - */
|
| -static const png_uint_32
|
| -png_32bit_exp[16] =
|
| -{
|
| - /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
|
| - 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
|
| - 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
|
| - 2553802834U, 2445529972U, 2341847524U, 2242560872U
|
| -};
|
| -
|
| -/* Adjustment table; provided to explain the numbers in the code below. */
|
| -#if 0
|
| -for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
|
| - 11 44937.64284865548751208448
|
| - 10 45180.98734845585101160448
|
| - 9 45303.31936980687359311872
|
| - 8 45364.65110595323018870784
|
| - 7 45395.35850361789624614912
|
| - 6 45410.72259715102037508096
|
| - 5 45418.40724413220722311168
|
| - 4 45422.25021786898173001728
|
| - 3 45424.17186732298419044352
|
| - 2 45425.13273269940811464704
|
| - 1 45425.61317555035558641664
|
| - 0 45425.85339951654943850496
|
| -#endif
|
| -
|
| -static png_uint_32
|
| -png_exp(png_fixed_point x)
|
| -{
|
| - if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
|
| - {
|
| - /* Obtain a 4-bit approximation */
|
| - png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf];
|
| -
|
| - /* Incorporate the low 12 bits - these decrease the returned value by
|
| - * multiplying by a number less than 1 if the bit is set. The multiplier
|
| - * is determined by the above table and the shift. Notice that the values
|
| - * converge on 45426 and this is used to allow linear interpolation of the
|
| - * low bits.
|
| - */
|
| - if (x & 0x800)
|
| - e -= (((e >> 16) * 44938U) + 16U) >> 5;
|
| -
|
| - if (x & 0x400)
|
| - e -= (((e >> 16) * 45181U) + 32U) >> 6;
|
| -
|
| - if (x & 0x200)
|
| - e -= (((e >> 16) * 45303U) + 64U) >> 7;
|
| -
|
| - if (x & 0x100)
|
| - e -= (((e >> 16) * 45365U) + 128U) >> 8;
|
| -
|
| - if (x & 0x080)
|
| - e -= (((e >> 16) * 45395U) + 256U) >> 9;
|
| -
|
| - if (x & 0x040)
|
| - e -= (((e >> 16) * 45410U) + 512U) >> 10;
|
| -
|
| - /* And handle the low 6 bits in a single block. */
|
| - e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
|
| -
|
| - /* Handle the upper bits of x. */
|
| - e >>= x >> 16;
|
| - return e;
|
| - }
|
| -
|
| - /* Check for overflow */
|
| - if (x <= 0)
|
| - return png_32bit_exp[0];
|
| -
|
| - /* Else underflow */
|
| - return 0;
|
| -}
|
| -
|
| -static png_byte
|
| -png_exp8bit(png_fixed_point lg2)
|
| -{
|
| - /* Get a 32-bit value: */
|
| - png_uint_32 x = png_exp(lg2);
|
| -
|
| - /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the
|
| - * second, rounding, step can't overflow because of the first, subtraction,
|
| - * step.
|
| - */
|
| - x -= x >> 8;
|
| - return (png_byte)((x + 0x7fffffU) >> 24);
|
| -}
|
| -
|
| -static png_uint_16
|
| -png_exp16bit(png_fixed_point lg2)
|
| -{
|
| - /* Get a 32-bit value: */
|
| - png_uint_32 x = png_exp(lg2);
|
| -
|
| - /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
|
| - x -= x >> 16;
|
| - return (png_uint_16)((x + 32767U) >> 16);
|
| -}
|
| -#endif /* FLOATING_ARITHMETIC */
|
| -
|
| -png_byte
|
| -png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
|
| -{
|
| - if (value > 0 && value < 255)
|
| - {
|
| -# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - double r = floor(255*pow(value/255.,gamma_val*.00001)+.5);
|
| - return (png_byte)r;
|
| -# else
|
| - png_int_32 lg2 = png_log8bit(value);
|
| - png_fixed_point res;
|
| -
|
| - if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1))
|
| - return png_exp8bit(res);
|
| -
|
| - /* Overflow. */
|
| - value = 0;
|
| -# endif
|
| - }
|
| -
|
| - return (png_byte)value;
|
| -}
|
| -
|
| -png_uint_16
|
| -png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
|
| -{
|
| - if (value > 0 && value < 65535)
|
| - {
|
| -# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - double r = floor(65535*pow(value/65535.,gamma_val*.00001)+.5);
|
| - return (png_uint_16)r;
|
| -# else
|
| - png_int_32 lg2 = png_log16bit(value);
|
| - png_fixed_point res;
|
| -
|
| - if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1))
|
| - return png_exp16bit(res);
|
| -
|
| - /* Overflow. */
|
| - value = 0;
|
| -# endif
|
| - }
|
| -
|
| - return (png_uint_16)value;
|
| -}
|
| -
|
| -/* This does the right thing based on the bit_depth field of the
|
| - * png_struct, interpreting values as 8-bit or 16-bit. While the result
|
| - * is nominally a 16-bit value if bit depth is 8 then the result is
|
| - * 8-bit (as are the arguments.)
|
| - */
|
| -png_uint_16 /* PRIVATE */
|
| -png_gamma_correct(png_structrp png_ptr, unsigned int value,
|
| - png_fixed_point gamma_val)
|
| -{
|
| - if (png_ptr->bit_depth == 8)
|
| - return png_gamma_8bit_correct(value, gamma_val);
|
| -
|
| - else
|
| - return png_gamma_16bit_correct(value, gamma_val);
|
| -}
|
| -
|
| -/* Internal function to build a single 16-bit table - the table consists of
|
| - * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
|
| - * to shift the input values right (or 16-number_of_signifiant_bits).
|
| - *
|
| - * The caller is responsible for ensuring that the table gets cleaned up on
|
| - * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
|
| - * should be somewhere that will be cleaned.
|
| - */
|
| -static void
|
| -png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
|
| - PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
|
| -{
|
| - /* Various values derived from 'shift': */
|
| - PNG_CONST unsigned int num = 1U << (8U - shift);
|
| - PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
|
| - PNG_CONST unsigned int max_by_2 = 1U << (15U-shift);
|
| - unsigned int i;
|
| -
|
| - png_uint_16pp table = *ptable =
|
| - (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
|
| -
|
| - for (i = 0; i < num; i++)
|
| - {
|
| - png_uint_16p sub_table = table[i] =
|
| - (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16)));
|
| -
|
| - /* The 'threshold' test is repeated here because it can arise for one of
|
| - * the 16-bit tables even if the others don't hit it.
|
| - */
|
| - if (png_gamma_significant(gamma_val))
|
| - {
|
| - /* The old code would overflow at the end and this would cause the
|
| - * 'pow' function to return a result >1, resulting in an
|
| - * arithmetic error. This code follows the spec exactly; ig is
|
| - * the recovered input sample, it always has 8-16 bits.
|
| - *
|
| - * We want input * 65535/max, rounded, the arithmetic fits in 32
|
| - * bits (unsigned) so long as max <= 32767.
|
| - */
|
| - unsigned int j;
|
| - for (j = 0; j < 256; j++)
|
| - {
|
| - png_uint_32 ig = (j << (8-shift)) + i;
|
| -# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| - /* Inline the 'max' scaling operation: */
|
| - double d = floor(65535*pow(ig/(double)max, gamma_val*.00001)+.5);
|
| - sub_table[j] = (png_uint_16)d;
|
| -# else
|
| - if (shift)
|
| - ig = (ig * 65535U + max_by_2)/max;
|
| -
|
| - sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
|
| -# endif
|
| - }
|
| - }
|
| - else
|
| - {
|
| - /* We must still build a table, but do it the fast way. */
|
| - unsigned int j;
|
| -
|
| - for (j = 0; j < 256; j++)
|
| - {
|
| - png_uint_32 ig = (j << (8-shift)) + i;
|
| -
|
| - if (shift)
|
| - ig = (ig * 65535U + max_by_2)/max;
|
| -
|
| - sub_table[j] = (png_uint_16)ig;
|
| - }
|
| - }
|
| - }
|
| -}
|
| -
|
| -/* NOTE: this function expects the *inverse* of the overall gamma transformation
|
| - * required.
|
| - */
|
| -static void
|
| -png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,
|
| - PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
|
| -{
|
| - PNG_CONST unsigned int num = 1U << (8U - shift);
|
| - PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
|
| - unsigned int i;
|
| - png_uint_32 last;
|
| -
|
| - png_uint_16pp table = *ptable =
|
| - (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
|
| -
|
| - /* 'num' is the number of tables and also the number of low bits of low
|
| - * bits of the input 16-bit value used to select a table. Each table is
|
| - * itself index by the high 8 bits of the value.
|
| - */
|
| - for (i = 0; i < num; i++)
|
| - table[i] = (png_uint_16p)png_malloc(png_ptr,
|
| - 256 * (sizeof (png_uint_16)));
|
| -
|
| - /* 'gamma_val' is set to the reciprocal of the value calculated above, so
|
| - * pow(out,g) is an *input* value. 'last' is the last input value set.
|
| - *
|
| - * In the loop 'i' is used to find output values. Since the output is
|
| - * 8-bit there are only 256 possible values. The tables are set up to
|
| - * select the closest possible output value for each input by finding
|
| - * the input value at the boundary between each pair of output values
|
| - * and filling the table up to that boundary with the lower output
|
| - * value.
|
| - *
|
| - * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit
|
| - * values the code below uses a 16-bit value in i; the values start at
|
| - * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
|
| - * entries are filled with 255). Start i at 128 and fill all 'last'
|
| - * table entries <= 'max'
|
| - */
|
| - last = 0;
|
| - for (i = 0; i < 255; ++i) /* 8-bit output value */
|
| - {
|
| - /* Find the corresponding maximum input value */
|
| - png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
|
| -
|
| - /* Find the boundary value in 16 bits: */
|
| - png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
|
| -
|
| - /* Adjust (round) to (16-shift) bits: */
|
| - bound = (bound * max + 32768U)/65535U + 1U;
|
| -
|
| - while (last < bound)
|
| - {
|
| - table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
|
| - last++;
|
| - }
|
| - }
|
| -
|
| - /* And fill in the final entries. */
|
| - while (last < (num << 8))
|
| - {
|
| - table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
|
| - last++;
|
| - }
|
| -}
|
| -
|
| -/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
|
| - * typically much faster). Note that libpng currently does no sBIT processing
|
| - * (apparently contrary to the spec) so a 256 entry table is always generated.
|
| - */
|
| -static void
|
| -png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
|
| - PNG_CONST png_fixed_point gamma_val)
|
| -{
|
| - unsigned int i;
|
| - png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
|
| -
|
| - if (png_gamma_significant(gamma_val)) for (i=0; i<256; i++)
|
| - table[i] = png_gamma_8bit_correct(i, gamma_val);
|
| -
|
| - else for (i=0; i<256; ++i)
|
| - table[i] = (png_byte)i;
|
| -}
|
| -
|
| -/* Used from png_read_destroy and below to release the memory used by the gamma
|
| - * tables.
|
| - */
|
| -void /* PRIVATE */
|
| -png_destroy_gamma_table(png_structrp png_ptr)
|
| -{
|
| - png_free(png_ptr, png_ptr->gamma_table);
|
| - png_ptr->gamma_table = NULL;
|
| -
|
| - if (png_ptr->gamma_16_table != NULL)
|
| - {
|
| - int i;
|
| - int istop = (1 << (8 - png_ptr->gamma_shift));
|
| - for (i = 0; i < istop; i++)
|
| - {
|
| - png_free(png_ptr, png_ptr->gamma_16_table[i]);
|
| - }
|
| - png_free(png_ptr, png_ptr->gamma_16_table);
|
| - png_ptr->gamma_16_table = NULL;
|
| - }
|
| -
|
| -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| - defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
|
| - defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
|
| - png_free(png_ptr, png_ptr->gamma_from_1);
|
| - png_ptr->gamma_from_1 = NULL;
|
| - png_free(png_ptr, png_ptr->gamma_to_1);
|
| - png_ptr->gamma_to_1 = NULL;
|
| -
|
| - if (png_ptr->gamma_16_from_1 != NULL)
|
| - {
|
| - int i;
|
| - int istop = (1 << (8 - png_ptr->gamma_shift));
|
| - for (i = 0; i < istop; i++)
|
| - {
|
| - png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
|
| - }
|
| - png_free(png_ptr, png_ptr->gamma_16_from_1);
|
| - png_ptr->gamma_16_from_1 = NULL;
|
| - }
|
| - if (png_ptr->gamma_16_to_1 != NULL)
|
| - {
|
| - int i;
|
| - int istop = (1 << (8 - png_ptr->gamma_shift));
|
| - for (i = 0; i < istop; i++)
|
| - {
|
| - png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
|
| - }
|
| - png_free(png_ptr, png_ptr->gamma_16_to_1);
|
| - png_ptr->gamma_16_to_1 = NULL;
|
| - }
|
| -#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
|
| -}
|
| -
|
| -/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
|
| - * tables, we don't make a full table if we are reducing to 8-bit in
|
| - * the future. Note also how the gamma_16 tables are segmented so that
|
| - * we don't need to allocate > 64K chunks for a full 16-bit table.
|
| - */
|
| -void /* PRIVATE */
|
| -png_build_gamma_table(png_structrp png_ptr, int bit_depth)
|
| -{
|
| - png_debug(1, "in png_build_gamma_table");
|
| -
|
| - /* Remove any existing table; this copes with multiple calls to
|
| - * png_read_update_info. The warning is because building the gamma tables
|
| - * multiple times is a performance hit - it's harmless but the ability to call
|
| - * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible
|
| - * to warn if the app introduces such a hit.
|
| - */
|
| - if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
|
| - {
|
| - png_warning(png_ptr, "gamma table being rebuilt");
|
| - png_destroy_gamma_table(png_ptr);
|
| - }
|
| -
|
| - if (bit_depth <= 8)
|
| - {
|
| - png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
|
| - png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
|
| - png_ptr->screen_gamma) : PNG_FP_1);
|
| -
|
| -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| - defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
|
| - defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
|
| - if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
|
| - {
|
| - png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
|
| - png_reciprocal(png_ptr->colorspace.gamma));
|
| -
|
| - png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
|
| - png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
|
| - png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
|
| - }
|
| -#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
|
| - }
|
| - else
|
| - {
|
| - png_byte shift, sig_bit;
|
| -
|
| - if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
|
| - {
|
| - sig_bit = png_ptr->sig_bit.red;
|
| -
|
| - if (png_ptr->sig_bit.green > sig_bit)
|
| - sig_bit = png_ptr->sig_bit.green;
|
| -
|
| - if (png_ptr->sig_bit.blue > sig_bit)
|
| - sig_bit = png_ptr->sig_bit.blue;
|
| - }
|
| - else
|
| - sig_bit = png_ptr->sig_bit.gray;
|
| -
|
| - /* 16-bit gamma code uses this equation:
|
| - *
|
| - * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
|
| - *
|
| - * Where 'iv' is the input color value and 'ov' is the output value -
|
| - * pow(iv, gamma).
|
| - *
|
| - * Thus the gamma table consists of up to 256 256 entry tables. The table
|
| - * is selected by the (8-gamma_shift) most significant of the low 8 bits of
|
| - * the color value then indexed by the upper 8 bits:
|
| - *
|
| - * table[low bits][high 8 bits]
|
| - *
|
| - * So the table 'n' corresponds to all those 'iv' of:
|
| - *
|
| - * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
|
| - *
|
| - */
|
| - if (sig_bit > 0 && sig_bit < 16U)
|
| - shift = (png_byte)(16U - sig_bit); /* shift == insignificant bits */
|
| -
|
| - else
|
| - shift = 0; /* keep all 16 bits */
|
| -
|
| - if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
|
| - {
|
| - /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
|
| - * the significant bits in the *input* when the output will
|
| - * eventually be 8 bits. By default it is 11.
|
| - */
|
| - if (shift < (16U - PNG_MAX_GAMMA_8))
|
| - shift = (16U - PNG_MAX_GAMMA_8);
|
| - }
|
| -
|
| - if (shift > 8U)
|
| - shift = 8U; /* Guarantees at least one table! */
|
| -
|
| - png_ptr->gamma_shift = shift;
|
| -
|
| -#ifdef PNG_16BIT_SUPPORTED
|
| - /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
|
| - * PNG_COMPOSE). This effectively smashed the background calculation for
|
| - * 16-bit output because the 8-bit table assumes the result will be reduced
|
| - * to 8 bits.
|
| - */
|
| - if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
|
| -#endif
|
| - png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
|
| - png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
|
| - png_ptr->screen_gamma) : PNG_FP_1);
|
| -
|
| -#ifdef PNG_16BIT_SUPPORTED
|
| - else
|
| - png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
|
| - png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
|
| - png_ptr->screen_gamma) : PNG_FP_1);
|
| -#endif
|
| -
|
| -#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| - defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
|
| - defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
|
| - if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
|
| - {
|
| - png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
|
| - png_reciprocal(png_ptr->colorspace.gamma));
|
| -
|
| - /* Notice that the '16 from 1' table should be full precision, however
|
| - * the lookup on this table still uses gamma_shift, so it can't be.
|
| - * TODO: fix this.
|
| - */
|
| - png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
|
| - png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
|
| - png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
|
| - }
|
| -#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
|
| - }
|
| -}
|
| -#endif /* READ_GAMMA */
|
| -
|
| -/* HARDWARE OPTION SUPPORT */
|
| -#ifdef PNG_SET_OPTION_SUPPORTED
|
| -int PNGAPI
|
| -png_set_option(png_structrp png_ptr, int option, int onoff)
|
| -{
|
| - if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
|
| - (option & 1) == 0)
|
| - {
|
| - int mask = 3 << option;
|
| - int setting = (2 + (onoff != 0)) << option;
|
| - int current = png_ptr->options;
|
| -
|
| - png_ptr->options = (png_byte)((current & ~mask) | setting);
|
| -
|
| - return (current & mask) >> option;
|
| - }
|
| -
|
| - return PNG_OPTION_INVALID;
|
| -}
|
| -#endif
|
| -
|
| -/* sRGB support */
|
| -#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
|
| - defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
|
| -/* sRGB conversion tables; these are machine generated with the code in
|
| - * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the
|
| - * specification (see the article at http://en.wikipedia.org/wiki/SRGB)
|
| - * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
|
| - * The sRGB to linear table is exact (to the nearest 16 bit linear fraction).
|
| - * The inverse (linear to sRGB) table has accuracies as follows:
|
| - *
|
| - * For all possible (255*65535+1) input values:
|
| - *
|
| - * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact
|
| - *
|
| - * For the input values corresponding to the 65536 16-bit values:
|
| - *
|
| - * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
|
| - *
|
| - * In all cases the inexact readings are off by one.
|
| - */
|
| -
|
| -#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
| -/* The convert-to-sRGB table is only currently required for read. */
|
| -const png_uint_16 png_sRGB_table[256] =
|
| -{
|
| - 0,20,40,60,80,99,119,139,
|
| - 159,179,199,219,241,264,288,313,
|
| - 340,367,396,427,458,491,526,562,
|
| - 599,637,677,718,761,805,851,898,
|
| - 947,997,1048,1101,1156,1212,1270,1330,
|
| - 1391,1453,1517,1583,1651,1720,1790,1863,
|
| - 1937,2013,2090,2170,2250,2333,2418,2504,
|
| - 2592,2681,2773,2866,2961,3058,3157,3258,
|
| - 3360,3464,3570,3678,3788,3900,4014,4129,
|
| - 4247,4366,4488,4611,4736,4864,4993,5124,
|
| - 5257,5392,5530,5669,5810,5953,6099,6246,
|
| - 6395,6547,6700,6856,7014,7174,7335,7500,
|
| - 7666,7834,8004,8177,8352,8528,8708,8889,
|
| - 9072,9258,9445,9635,9828,10022,10219,10417,
|
| - 10619,10822,11028,11235,11446,11658,11873,12090,
|
| - 12309,12530,12754,12980,13209,13440,13673,13909,
|
| - 14146,14387,14629,14874,15122,15371,15623,15878,
|
| - 16135,16394,16656,16920,17187,17456,17727,18001,
|
| - 18277,18556,18837,19121,19407,19696,19987,20281,
|
| - 20577,20876,21177,21481,21787,22096,22407,22721,
|
| - 23038,23357,23678,24002,24329,24658,24990,25325,
|
| - 25662,26001,26344,26688,27036,27386,27739,28094,
|
| - 28452,28813,29176,29542,29911,30282,30656,31033,
|
| - 31412,31794,32179,32567,32957,33350,33745,34143,
|
| - 34544,34948,35355,35764,36176,36591,37008,37429,
|
| - 37852,38278,38706,39138,39572,40009,40449,40891,
|
| - 41337,41785,42236,42690,43147,43606,44069,44534,
|
| - 45002,45473,45947,46423,46903,47385,47871,48359,
|
| - 48850,49344,49841,50341,50844,51349,51858,52369,
|
| - 52884,53401,53921,54445,54971,55500,56032,56567,
|
| - 57105,57646,58190,58737,59287,59840,60396,60955,
|
| - 61517,62082,62650,63221,63795,64372,64952,65535
|
| -};
|
| -
|
| -#endif /* simplified read only */
|
| -
|
| -/* The base/delta tables are required for both read and write (but currently
|
| - * only the simplified versions.)
|
| - */
|
| -const png_uint_16 png_sRGB_base[512] =
|
| -{
|
| - 128,1782,3383,4644,5675,6564,7357,8074,
|
| - 8732,9346,9921,10463,10977,11466,11935,12384,
|
| - 12816,13233,13634,14024,14402,14769,15125,15473,
|
| - 15812,16142,16466,16781,17090,17393,17690,17981,
|
| - 18266,18546,18822,19093,19359,19621,19879,20133,
|
| - 20383,20630,20873,21113,21349,21583,21813,22041,
|
| - 22265,22487,22707,22923,23138,23350,23559,23767,
|
| - 23972,24175,24376,24575,24772,24967,25160,25352,
|
| - 25542,25730,25916,26101,26284,26465,26645,26823,
|
| - 27000,27176,27350,27523,27695,27865,28034,28201,
|
| - 28368,28533,28697,28860,29021,29182,29341,29500,
|
| - 29657,29813,29969,30123,30276,30429,30580,30730,
|
| - 30880,31028,31176,31323,31469,31614,31758,31902,
|
| - 32045,32186,32327,32468,32607,32746,32884,33021,
|
| - 33158,33294,33429,33564,33697,33831,33963,34095,
|
| - 34226,34357,34486,34616,34744,34873,35000,35127,
|
| - 35253,35379,35504,35629,35753,35876,35999,36122,
|
| - 36244,36365,36486,36606,36726,36845,36964,37083,
|
| - 37201,37318,37435,37551,37668,37783,37898,38013,
|
| - 38127,38241,38354,38467,38580,38692,38803,38915,
|
| - 39026,39136,39246,39356,39465,39574,39682,39790,
|
| - 39898,40005,40112,40219,40325,40431,40537,40642,
|
| - 40747,40851,40955,41059,41163,41266,41369,41471,
|
| - 41573,41675,41777,41878,41979,42079,42179,42279,
|
| - 42379,42478,42577,42676,42775,42873,42971,43068,
|
| - 43165,43262,43359,43456,43552,43648,43743,43839,
|
| - 43934,44028,44123,44217,44311,44405,44499,44592,
|
| - 44685,44778,44870,44962,45054,45146,45238,45329,
|
| - 45420,45511,45601,45692,45782,45872,45961,46051,
|
| - 46140,46229,46318,46406,46494,46583,46670,46758,
|
| - 46846,46933,47020,47107,47193,47280,47366,47452,
|
| - 47538,47623,47709,47794,47879,47964,48048,48133,
|
| - 48217,48301,48385,48468,48552,48635,48718,48801,
|
| - 48884,48966,49048,49131,49213,49294,49376,49458,
|
| - 49539,49620,49701,49782,49862,49943,50023,50103,
|
| - 50183,50263,50342,50422,50501,50580,50659,50738,
|
| - 50816,50895,50973,51051,51129,51207,51285,51362,
|
| - 51439,51517,51594,51671,51747,51824,51900,51977,
|
| - 52053,52129,52205,52280,52356,52432,52507,52582,
|
| - 52657,52732,52807,52881,52956,53030,53104,53178,
|
| - 53252,53326,53400,53473,53546,53620,53693,53766,
|
| - 53839,53911,53984,54056,54129,54201,54273,54345,
|
| - 54417,54489,54560,54632,54703,54774,54845,54916,
|
| - 54987,55058,55129,55199,55269,55340,55410,55480,
|
| - 55550,55620,55689,55759,55828,55898,55967,56036,
|
| - 56105,56174,56243,56311,56380,56448,56517,56585,
|
| - 56653,56721,56789,56857,56924,56992,57059,57127,
|
| - 57194,57261,57328,57395,57462,57529,57595,57662,
|
| - 57728,57795,57861,57927,57993,58059,58125,58191,
|
| - 58256,58322,58387,58453,58518,58583,58648,58713,
|
| - 58778,58843,58908,58972,59037,59101,59165,59230,
|
| - 59294,59358,59422,59486,59549,59613,59677,59740,
|
| - 59804,59867,59930,59993,60056,60119,60182,60245,
|
| - 60308,60370,60433,60495,60558,60620,60682,60744,
|
| - 60806,60868,60930,60992,61054,61115,61177,61238,
|
| - 61300,61361,61422,61483,61544,61605,61666,61727,
|
| - 61788,61848,61909,61969,62030,62090,62150,62211,
|
| - 62271,62331,62391,62450,62510,62570,62630,62689,
|
| - 62749,62808,62867,62927,62986,63045,63104,63163,
|
| - 63222,63281,63340,63398,63457,63515,63574,63632,
|
| - 63691,63749,63807,63865,63923,63981,64039,64097,
|
| - 64155,64212,64270,64328,64385,64443,64500,64557,
|
| - 64614,64672,64729,64786,64843,64900,64956,65013,
|
| - 65070,65126,65183,65239,65296,65352,65409,65465
|
| -};
|
| -
|
| -const png_byte png_sRGB_delta[512] =
|
| -{
|
| - 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54,
|
| - 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36,
|
| - 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28,
|
| - 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24,
|
| - 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21,
|
| - 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19,
|
| - 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17,
|
| - 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16,
|
| - 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15,
|
| - 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14,
|
| - 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13,
|
| - 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12,
|
| - 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
|
| - 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11,
|
| - 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
|
| - 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
|
| - 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
|
| - 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
|
| - 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
|
| - 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| - 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| - 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| - 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| - 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| - 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| - 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| - 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| - 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| - 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,
|
| - 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
|
| - 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
|
| - 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
|
| -};
|
| -#endif /* SIMPLIFIED READ/WRITE sRGB support */
|
| -
|
| -/* SIMPLIFIED READ/WRITE SUPPORT */
|
| -#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
|
| - defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
|
| -static int
|
| -png_image_free_function(png_voidp argument)
|
| -{
|
| - png_imagep image = png_voidcast(png_imagep, argument);
|
| - png_controlp cp = image->opaque;
|
| - png_control c;
|
| -
|
| - /* Double check that we have a png_ptr - it should be impossible to get here
|
| - * without one.
|
| - */
|
| - if (cp->png_ptr == NULL)
|
| - return 0;
|
| -
|
| - /* First free any data held in the control structure. */
|
| -# ifdef PNG_STDIO_SUPPORTED
|
| - if (cp->owned_file)
|
| - {
|
| - FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
|
| - cp->owned_file = 0;
|
| -
|
| - /* Ignore errors here. */
|
| - if (fp != NULL)
|
| - {
|
| - cp->png_ptr->io_ptr = NULL;
|
| - (void)fclose(fp);
|
| - }
|
| - }
|
| -# endif
|
| -
|
| - /* Copy the control structure so that the original, allocated, version can be
|
| - * safely freed. Notice that a png_error here stops the remainder of the
|
| - * cleanup, but this is probably fine because that would indicate bad memory
|
| - * problems anyway.
|
| - */
|
| - c = *cp;
|
| - image->opaque = &c;
|
| - png_free(c.png_ptr, cp);
|
| -
|
| - /* Then the structures, calling the correct API. */
|
| - if (c.for_write)
|
| - {
|
| -# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
|
| - png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
|
| -# else
|
| - png_error(c.png_ptr, "simplified write not supported");
|
| -# endif
|
| - }
|
| - else
|
| - {
|
| -# ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
| - png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL);
|
| -# else
|
| - png_error(c.png_ptr, "simplified read not supported");
|
| -# endif
|
| - }
|
| -
|
| - /* Success. */
|
| - return 1;
|
| -}
|
| -
|
| -void PNGAPI
|
| -png_image_free(png_imagep image)
|
| -{
|
| - /* Safely call the real function, but only if doing so is safe at this point
|
| - * (if not inside an error handling context). Otherwise assume
|
| - * png_safe_execute will call this API after the return.
|
| - */
|
| - if (image != NULL && image->opaque != NULL &&
|
| - image->opaque->error_buf == NULL)
|
| - {
|
| - /* Ignore errors here: */
|
| - (void)png_safe_execute(image, png_image_free_function, image);
|
| - image->opaque = NULL;
|
| - }
|
| -}
|
| -
|
| -int /* PRIVATE */
|
| -png_image_error(png_imagep image, png_const_charp error_message)
|
| -{
|
| - /* Utility to log an error. */
|
| - png_safecat(image->message, (sizeof image->message), 0, error_message);
|
| - image->warning_or_error |= PNG_IMAGE_ERROR;
|
| - png_image_free(image);
|
| - return 0;
|
| -}
|
| -
|
| -#endif /* SIMPLIFIED READ/WRITE */
|
| -#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
|
| +
|
| +/* png.c - location for general purpose libpng functions
|
| + *
|
| + * Last changed in libpng 1.6.19 [November 12, 2015]
|
| + * Copyright (c) 1998-2015 Glenn Randers-Pehrson
|
| + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
|
| + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
|
| + *
|
| + * This code is released under the libpng license.
|
| + * For conditions of distribution and use, see the disclaimer
|
| + * and license in png.h
|
| + */
|
| +
|
| +#include "pngpriv.h"
|
| +
|
| +/* Generate a compiler error if there is an old png.h in the search path. */
|
| +typedef png_libpng_version_1_6_20 Your_png_h_is_not_version_1_6_20;
|
| +
|
| +/* Tells libpng that we have already handled the first "num_bytes" bytes
|
| + * of the PNG file signature. If the PNG data is embedded into another
|
| + * stream we can set num_bytes = 8 so that libpng will not attempt to read
|
| + * or write any of the magic bytes before it starts on the IHDR.
|
| + */
|
| +
|
| +#ifdef PNG_READ_SUPPORTED
|
| +void PNGAPI
|
| +png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
|
| +{
|
| + unsigned int nb = (unsigned int)num_bytes;
|
| +
|
| + png_debug(1, "in png_set_sig_bytes");
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + if (num_bytes < 0)
|
| + nb = 0;
|
| +
|
| + if (nb > 8)
|
| + png_error(png_ptr, "Too many bytes for PNG signature");
|
| +
|
| + png_ptr->sig_bytes = (png_byte)nb;
|
| +}
|
| +
|
| +/* Checks whether the supplied bytes match the PNG signature. We allow
|
| + * checking less than the full 8-byte signature so that those apps that
|
| + * already read the first few bytes of a file to determine the file type
|
| + * can simply check the remaining bytes for extra assurance. Returns
|
| + * an integer less than, equal to, or greater than zero if sig is found,
|
| + * respectively, to be less than, to match, or be greater than the correct
|
| + * PNG signature (this is the same behavior as strcmp, memcmp, etc).
|
| + */
|
| +int PNGAPI
|
| +png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
|
| +{
|
| + png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
|
| +
|
| + if (num_to_check > 8)
|
| + num_to_check = 8;
|
| +
|
| + else if (num_to_check < 1)
|
| + return (-1);
|
| +
|
| + if (start > 7)
|
| + return (-1);
|
| +
|
| + if (start + num_to_check > 8)
|
| + num_to_check = 8 - start;
|
| +
|
| + return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check)));
|
| +}
|
| +
|
| +#endif /* READ */
|
| +
|
| +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
|
| +/* Function to allocate memory for zlib */
|
| +PNG_FUNCTION(voidpf /* PRIVATE */,
|
| +png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
|
| +{
|
| + png_alloc_size_t num_bytes = size;
|
| +
|
| + if (png_ptr == NULL)
|
| + return NULL;
|
| +
|
| + if (items >= (~(png_alloc_size_t)0)/size)
|
| + {
|
| + png_warning (png_voidcast(png_structrp, png_ptr),
|
| + "Potential overflow in png_zalloc()");
|
| + return NULL;
|
| + }
|
| +
|
| + num_bytes *= items;
|
| + return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
|
| +}
|
| +
|
| +/* Function to free memory for zlib */
|
| +void /* PRIVATE */
|
| +png_zfree(voidpf png_ptr, voidpf ptr)
|
| +{
|
| + png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
|
| +}
|
| +
|
| +/* Reset the CRC variable to 32 bits of 1's. Care must be taken
|
| + * in case CRC is > 32 bits to leave the top bits 0.
|
| + */
|
| +void /* PRIVATE */
|
| +png_reset_crc(png_structrp png_ptr)
|
| +{
|
| + /* The cast is safe because the crc is a 32-bit value. */
|
| + png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
|
| +}
|
| +
|
| +/* Calculate the CRC over a section of data. We can only pass as
|
| + * much data to this routine as the largest single buffer size. We
|
| + * also check that this data will actually be used before going to the
|
| + * trouble of calculating it.
|
| + */
|
| +void /* PRIVATE */
|
| +png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
|
| +{
|
| + int need_crc = 1;
|
| +
|
| + if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
|
| + {
|
| + if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
|
| + (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
|
| + need_crc = 0;
|
| + }
|
| +
|
| + else /* critical */
|
| + {
|
| + if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
|
| + need_crc = 0;
|
| + }
|
| +
|
| + /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
|
| + * systems it is a 64-bit value. crc32, however, returns 32 bits so the
|
| + * following cast is safe. 'uInt' may be no more than 16 bits, so it is
|
| + * necessary to perform a loop here.
|
| + */
|
| + if (need_crc != 0 && length > 0)
|
| + {
|
| + uLong crc = png_ptr->crc; /* Should never issue a warning */
|
| +
|
| + do
|
| + {
|
| + uInt safe_length = (uInt)length;
|
| +#ifndef __COVERITY__
|
| + if (safe_length == 0)
|
| + safe_length = (uInt)-1; /* evil, but safe */
|
| +#endif
|
| +
|
| + crc = crc32(crc, ptr, safe_length);
|
| +
|
| + /* The following should never issue compiler warnings; if they do the
|
| + * target system has characteristics that will probably violate other
|
| + * assumptions within the libpng code.
|
| + */
|
| + ptr += safe_length;
|
| + length -= safe_length;
|
| + }
|
| + while (length > 0);
|
| +
|
| + /* And the following is always safe because the crc is only 32 bits. */
|
| + png_ptr->crc = (png_uint_32)crc;
|
| + }
|
| +}
|
| +
|
| +/* Check a user supplied version number, called from both read and write
|
| + * functions that create a png_struct.
|
| + */
|
| +int
|
| +png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
|
| +{
|
| + /* Libpng versions 1.0.0 and later are binary compatible if the version
|
| + * string matches through the second '.'; we must recompile any
|
| + * applications that use any older library version.
|
| + */
|
| +
|
| + if (user_png_ver != NULL)
|
| + {
|
| + int i = -1;
|
| + int found_dots = 0;
|
| +
|
| + do
|
| + {
|
| + i++;
|
| + if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i])
|
| + png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
|
| + if (user_png_ver[i] == '.')
|
| + found_dots++;
|
| + } while (found_dots < 2 && user_png_ver[i] != 0 &&
|
| + PNG_LIBPNG_VER_STRING[i] != 0);
|
| + }
|
| +
|
| + else
|
| + png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
|
| +
|
| + if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
|
| + {
|
| +#ifdef PNG_WARNINGS_SUPPORTED
|
| + size_t pos = 0;
|
| + char m[128];
|
| +
|
| + pos = png_safecat(m, (sizeof m), pos,
|
| + "Application built with libpng-");
|
| + pos = png_safecat(m, (sizeof m), pos, user_png_ver);
|
| + pos = png_safecat(m, (sizeof m), pos, " but running with ");
|
| + pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING);
|
| + PNG_UNUSED(pos)
|
| +
|
| + png_warning(png_ptr, m);
|
| +#endif
|
| +
|
| +#ifdef PNG_ERROR_NUMBERS_SUPPORTED
|
| + png_ptr->flags = 0;
|
| +#endif
|
| +
|
| + return 0;
|
| + }
|
| +
|
| + /* Success return. */
|
| + return 1;
|
| +}
|
| +
|
| +/* Generic function to create a png_struct for either read or write - this
|
| + * contains the common initialization.
|
| + */
|
| +PNG_FUNCTION(png_structp /* PRIVATE */,
|
| +png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
|
| + png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
|
| + png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
|
| +{
|
| + png_struct create_struct;
|
| +# ifdef PNG_SETJMP_SUPPORTED
|
| + jmp_buf create_jmp_buf;
|
| +# endif
|
| +
|
| + /* This temporary stack-allocated structure is used to provide a place to
|
| + * build enough context to allow the user provided memory allocator (if any)
|
| + * to be called.
|
| + */
|
| + memset(&create_struct, 0, (sizeof create_struct));
|
| +
|
| + /* Added at libpng-1.2.6 */
|
| +# ifdef PNG_USER_LIMITS_SUPPORTED
|
| + create_struct.user_width_max = PNG_USER_WIDTH_MAX;
|
| + create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
|
| +
|
| +# ifdef PNG_USER_CHUNK_CACHE_MAX
|
| + /* Added at libpng-1.2.43 and 1.4.0 */
|
| + create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
|
| +# endif
|
| +
|
| +# ifdef PNG_USER_CHUNK_MALLOC_MAX
|
| + /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
|
| + * in png_struct regardless.
|
| + */
|
| + create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
|
| +# endif
|
| +# endif
|
| +
|
| + /* The following two API calls simply set fields in png_struct, so it is safe
|
| + * to do them now even though error handling is not yet set up.
|
| + */
|
| +# ifdef PNG_USER_MEM_SUPPORTED
|
| + png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
|
| +# else
|
| + PNG_UNUSED(mem_ptr)
|
| + PNG_UNUSED(malloc_fn)
|
| + PNG_UNUSED(free_fn)
|
| +# endif
|
| +
|
| + /* (*error_fn) can return control to the caller after the error_ptr is set,
|
| + * this will result in a memory leak unless the error_fn does something
|
| + * extremely sophisticated. The design lacks merit but is implicit in the
|
| + * API.
|
| + */
|
| + png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
|
| +
|
| +# ifdef PNG_SETJMP_SUPPORTED
|
| + if (!setjmp(create_jmp_buf))
|
| +# endif
|
| + {
|
| +# ifdef PNG_SETJMP_SUPPORTED
|
| + /* Temporarily fake out the longjmp information until we have
|
| + * successfully completed this function. This only works if we have
|
| + * setjmp() support compiled in, but it is safe - this stuff should
|
| + * never happen.
|
| + */
|
| + create_struct.jmp_buf_ptr = &create_jmp_buf;
|
| + create_struct.jmp_buf_size = 0; /*stack allocation*/
|
| + create_struct.longjmp_fn = longjmp;
|
| +# endif
|
| + /* Call the general version checker (shared with read and write code):
|
| + */
|
| + if (png_user_version_check(&create_struct, user_png_ver) != 0)
|
| + {
|
| + png_structrp png_ptr = png_voidcast(png_structrp,
|
| + png_malloc_warn(&create_struct, (sizeof *png_ptr)));
|
| +
|
| + if (png_ptr != NULL)
|
| + {
|
| + /* png_ptr->zstream holds a back-pointer to the png_struct, so
|
| + * this can only be done now:
|
| + */
|
| + create_struct.zstream.zalloc = png_zalloc;
|
| + create_struct.zstream.zfree = png_zfree;
|
| + create_struct.zstream.opaque = png_ptr;
|
| +
|
| +# ifdef PNG_SETJMP_SUPPORTED
|
| + /* Eliminate the local error handling: */
|
| + create_struct.jmp_buf_ptr = NULL;
|
| + create_struct.jmp_buf_size = 0;
|
| + create_struct.longjmp_fn = 0;
|
| +# endif
|
| +
|
| + *png_ptr = create_struct;
|
| +
|
| + /* This is the successful return point */
|
| + return png_ptr;
|
| + }
|
| + }
|
| + }
|
| +
|
| + /* A longjmp because of a bug in the application storage allocator or a
|
| + * simple failure to allocate the png_struct.
|
| + */
|
| + return NULL;
|
| +}
|
| +
|
| +/* Allocate the memory for an info_struct for the application. */
|
| +PNG_FUNCTION(png_infop,PNGAPI
|
| +png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
|
| +{
|
| + png_inforp info_ptr;
|
| +
|
| + png_debug(1, "in png_create_info_struct");
|
| +
|
| + if (png_ptr == NULL)
|
| + return NULL;
|
| +
|
| + /* Use the internal API that does not (or at least should not) error out, so
|
| + * that this call always returns ok. The application typically sets up the
|
| + * error handling *after* creating the info_struct because this is the way it
|
| + * has always been done in 'example.c'.
|
| + */
|
| + info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
|
| + (sizeof *info_ptr)));
|
| +
|
| + if (info_ptr != NULL)
|
| + memset(info_ptr, 0, (sizeof *info_ptr));
|
| +
|
| + return info_ptr;
|
| +}
|
| +
|
| +/* This function frees the memory associated with a single info struct.
|
| + * Normally, one would use either png_destroy_read_struct() or
|
| + * png_destroy_write_struct() to free an info struct, but this may be
|
| + * useful for some applications. From libpng 1.6.0 this function is also used
|
| + * internally to implement the png_info release part of the 'struct' destroy
|
| + * APIs. This ensures that all possible approaches free the same data (all of
|
| + * it).
|
| + */
|
| +void PNGAPI
|
| +png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
|
| +{
|
| + png_inforp info_ptr = NULL;
|
| +
|
| + png_debug(1, "in png_destroy_info_struct");
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + if (info_ptr_ptr != NULL)
|
| + info_ptr = *info_ptr_ptr;
|
| +
|
| + if (info_ptr != NULL)
|
| + {
|
| + /* Do this first in case of an error below; if the app implements its own
|
| + * memory management this can lead to png_free calling png_error, which
|
| + * will abort this routine and return control to the app error handler.
|
| + * An infinite loop may result if it then tries to free the same info
|
| + * ptr.
|
| + */
|
| + *info_ptr_ptr = NULL;
|
| +
|
| + png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
|
| + memset(info_ptr, 0, (sizeof *info_ptr));
|
| + png_free(png_ptr, info_ptr);
|
| + }
|
| +}
|
| +
|
| +/* Initialize the info structure. This is now an internal function (0.89)
|
| + * and applications using it are urged to use png_create_info_struct()
|
| + * instead. Use deprecated in 1.6.0, internal use removed (used internally it
|
| + * is just a memset).
|
| + *
|
| + * NOTE: it is almost inconceivable that this API is used because it bypasses
|
| + * the user-memory mechanism and the user error handling/warning mechanisms in
|
| + * those cases where it does anything other than a memset.
|
| + */
|
| +PNG_FUNCTION(void,PNGAPI
|
| +png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size),
|
| + PNG_DEPRECATED)
|
| +{
|
| + png_inforp info_ptr = *ptr_ptr;
|
| +
|
| + png_debug(1, "in png_info_init_3");
|
| +
|
| + if (info_ptr == NULL)
|
| + return;
|
| +
|
| + if ((sizeof (png_info)) > png_info_struct_size)
|
| + {
|
| + *ptr_ptr = NULL;
|
| + /* The following line is why this API should not be used: */
|
| + free(info_ptr);
|
| + info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
|
| + (sizeof *info_ptr)));
|
| + if (info_ptr == NULL)
|
| + return;
|
| + *ptr_ptr = info_ptr;
|
| + }
|
| +
|
| + /* Set everything to 0 */
|
| + memset(info_ptr, 0, (sizeof *info_ptr));
|
| +}
|
| +
|
| +/* The following API is not called internally */
|
| +void PNGAPI
|
| +png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
|
| + int freer, png_uint_32 mask)
|
| +{
|
| + png_debug(1, "in png_data_freer");
|
| +
|
| + if (png_ptr == NULL || info_ptr == NULL)
|
| + return;
|
| +
|
| + if (freer == PNG_DESTROY_WILL_FREE_DATA)
|
| + info_ptr->free_me |= mask;
|
| +
|
| + else if (freer == PNG_USER_WILL_FREE_DATA)
|
| + info_ptr->free_me &= ~mask;
|
| +
|
| + else
|
| + png_error(png_ptr, "Unknown freer parameter in png_data_freer");
|
| +}
|
| +
|
| +void PNGAPI
|
| +png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
|
| + int num)
|
| +{
|
| + png_debug(1, "in png_free_data");
|
| +
|
| + if (png_ptr == NULL || info_ptr == NULL)
|
| + return;
|
| +
|
| +#ifdef PNG_TEXT_SUPPORTED
|
| + /* Free text item num or (if num == -1) all text items */
|
| + if (info_ptr->text != 0 &&
|
| + ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
|
| + {
|
| + if (num != -1)
|
| + {
|
| + png_free(png_ptr, info_ptr->text[num].key);
|
| + info_ptr->text[num].key = NULL;
|
| + }
|
| +
|
| + else
|
| + {
|
| + int i;
|
| +
|
| + for (i = 0; i < info_ptr->num_text; i++)
|
| + png_free(png_ptr, info_ptr->text[i].key);
|
| +
|
| + png_free(png_ptr, info_ptr->text);
|
| + info_ptr->text = NULL;
|
| + info_ptr->num_text = 0;
|
| + }
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_tRNS_SUPPORTED
|
| + /* Free any tRNS entry */
|
| + if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
|
| + {
|
| + info_ptr->valid &= ~PNG_INFO_tRNS;
|
| + png_free(png_ptr, info_ptr->trans_alpha);
|
| + info_ptr->trans_alpha = NULL;
|
| + info_ptr->num_trans = 0;
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_sCAL_SUPPORTED
|
| + /* Free any sCAL entry */
|
| + if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
|
| + {
|
| + png_free(png_ptr, info_ptr->scal_s_width);
|
| + png_free(png_ptr, info_ptr->scal_s_height);
|
| + info_ptr->scal_s_width = NULL;
|
| + info_ptr->scal_s_height = NULL;
|
| + info_ptr->valid &= ~PNG_INFO_sCAL;
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_pCAL_SUPPORTED
|
| + /* Free any pCAL entry */
|
| + if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
|
| + {
|
| + png_free(png_ptr, info_ptr->pcal_purpose);
|
| + png_free(png_ptr, info_ptr->pcal_units);
|
| + info_ptr->pcal_purpose = NULL;
|
| + info_ptr->pcal_units = NULL;
|
| +
|
| + if (info_ptr->pcal_params != NULL)
|
| + {
|
| + int i;
|
| +
|
| + for (i = 0; i < info_ptr->pcal_nparams; i++)
|
| + png_free(png_ptr, info_ptr->pcal_params[i]);
|
| +
|
| + png_free(png_ptr, info_ptr->pcal_params);
|
| + info_ptr->pcal_params = NULL;
|
| + }
|
| + info_ptr->valid &= ~PNG_INFO_pCAL;
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_iCCP_SUPPORTED
|
| + /* Free any profile entry */
|
| + if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
|
| + {
|
| + png_free(png_ptr, info_ptr->iccp_name);
|
| + png_free(png_ptr, info_ptr->iccp_profile);
|
| + info_ptr->iccp_name = NULL;
|
| + info_ptr->iccp_profile = NULL;
|
| + info_ptr->valid &= ~PNG_INFO_iCCP;
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_sPLT_SUPPORTED
|
| + /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
|
| + if (info_ptr->splt_palettes != 0 &&
|
| + ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
|
| + {
|
| + if (num != -1)
|
| + {
|
| + png_free(png_ptr, info_ptr->splt_palettes[num].name);
|
| + png_free(png_ptr, info_ptr->splt_palettes[num].entries);
|
| + info_ptr->splt_palettes[num].name = NULL;
|
| + info_ptr->splt_palettes[num].entries = NULL;
|
| + }
|
| +
|
| + else
|
| + {
|
| + int i;
|
| +
|
| + for (i = 0; i < info_ptr->splt_palettes_num; i++)
|
| + {
|
| + png_free(png_ptr, info_ptr->splt_palettes[i].name);
|
| + png_free(png_ptr, info_ptr->splt_palettes[i].entries);
|
| + }
|
| +
|
| + png_free(png_ptr, info_ptr->splt_palettes);
|
| + info_ptr->splt_palettes = NULL;
|
| + info_ptr->splt_palettes_num = 0;
|
| + info_ptr->valid &= ~PNG_INFO_sPLT;
|
| + }
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
|
| + if (info_ptr->unknown_chunks != 0 &&
|
| + ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
|
| + {
|
| + if (num != -1)
|
| + {
|
| + png_free(png_ptr, info_ptr->unknown_chunks[num].data);
|
| + info_ptr->unknown_chunks[num].data = NULL;
|
| + }
|
| +
|
| + else
|
| + {
|
| + int i;
|
| +
|
| + for (i = 0; i < info_ptr->unknown_chunks_num; i++)
|
| + png_free(png_ptr, info_ptr->unknown_chunks[i].data);
|
| +
|
| + png_free(png_ptr, info_ptr->unknown_chunks);
|
| + info_ptr->unknown_chunks = NULL;
|
| + info_ptr->unknown_chunks_num = 0;
|
| + }
|
| + }
|
| +#endif
|
| +
|
| +#ifdef PNG_hIST_SUPPORTED
|
| + /* Free any hIST entry */
|
| + if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
|
| + {
|
| + png_free(png_ptr, info_ptr->hist);
|
| + info_ptr->hist = NULL;
|
| + info_ptr->valid &= ~PNG_INFO_hIST;
|
| + }
|
| +#endif
|
| +
|
| + /* Free any PLTE entry that was internally allocated */
|
| + if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
|
| + {
|
| + png_free(png_ptr, info_ptr->palette);
|
| + info_ptr->palette = NULL;
|
| + info_ptr->valid &= ~PNG_INFO_PLTE;
|
| + info_ptr->num_palette = 0;
|
| + }
|
| +
|
| +#ifdef PNG_INFO_IMAGE_SUPPORTED
|
| + /* Free any image bits attached to the info structure */
|
| + if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
|
| + {
|
| + if (info_ptr->row_pointers != 0)
|
| + {
|
| + png_uint_32 row;
|
| + for (row = 0; row < info_ptr->height; row++)
|
| + png_free(png_ptr, info_ptr->row_pointers[row]);
|
| +
|
| + png_free(png_ptr, info_ptr->row_pointers);
|
| + info_ptr->row_pointers = NULL;
|
| + }
|
| + info_ptr->valid &= ~PNG_INFO_IDAT;
|
| + }
|
| +#endif
|
| +
|
| + if (num != -1)
|
| + mask &= ~PNG_FREE_MUL;
|
| +
|
| + info_ptr->free_me &= ~mask;
|
| +}
|
| +#endif /* READ || WRITE */
|
| +
|
| +/* This function returns a pointer to the io_ptr associated with the user
|
| + * functions. The application should free any memory associated with this
|
| + * pointer before png_write_destroy() or png_read_destroy() are called.
|
| + */
|
| +png_voidp PNGAPI
|
| +png_get_io_ptr(png_const_structrp png_ptr)
|
| +{
|
| + if (png_ptr == NULL)
|
| + return (NULL);
|
| +
|
| + return (png_ptr->io_ptr);
|
| +}
|
| +
|
| +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
|
| +# ifdef PNG_STDIO_SUPPORTED
|
| +/* Initialize the default input/output functions for the PNG file. If you
|
| + * use your own read or write routines, you can call either png_set_read_fn()
|
| + * or png_set_write_fn() instead of png_init_io(). If you have defined
|
| + * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
|
| + * function of your own because "FILE *" isn't necessarily available.
|
| + */
|
| +void PNGAPI
|
| +png_init_io(png_structrp png_ptr, png_FILE_p fp)
|
| +{
|
| + png_debug(1, "in png_init_io");
|
| +
|
| + if (png_ptr == NULL)
|
| + return;
|
| +
|
| + png_ptr->io_ptr = (png_voidp)fp;
|
| +}
|
| +# endif
|
| +
|
| +# ifdef PNG_SAVE_INT_32_SUPPORTED
|
| +/* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90
|
| + * defines a cast of a signed integer to an unsigned integer either to preserve
|
| + * the value, if it is positive, or to calculate:
|
| + *
|
| + * (UNSIGNED_MAX+1) + integer
|
| + *
|
| + * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the
|
| + * negative integral value is added the result will be an unsigned value
|
| + * correspnding to the 2's complement representation.
|
| + */
|
| +void PNGAPI
|
| +png_save_int_32(png_bytep buf, png_int_32 i)
|
| +{
|
| + png_save_uint_32(buf, i);
|
| +}
|
| +# endif
|
| +
|
| +# ifdef PNG_TIME_RFC1123_SUPPORTED
|
| +/* Convert the supplied time into an RFC 1123 string suitable for use in
|
| + * a "Creation Time" or other text-based time string.
|
| + */
|
| +int PNGAPI
|
| +png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
|
| +{
|
| + static PNG_CONST char short_months[12][4] =
|
| + {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
|
| + "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
|
| +
|
| + if (out == NULL)
|
| + return 0;
|
| +
|
| + if (ptime->year > 9999 /* RFC1123 limitation */ ||
|
| + ptime->month == 0 || ptime->month > 12 ||
|
| + ptime->day == 0 || ptime->day > 31 ||
|
| + ptime->hour > 23 || ptime->minute > 59 ||
|
| + ptime->second > 60)
|
| + return 0;
|
| +
|
| + {
|
| + size_t pos = 0;
|
| + char number_buf[5]; /* enough for a four-digit year */
|
| +
|
| +# define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
|
| +# define APPEND_NUMBER(format, value)\
|
| + APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
|
| +# define APPEND(ch) if (pos < 28) out[pos++] = (ch)
|
| +
|
| + APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
|
| + APPEND(' ');
|
| + APPEND_STRING(short_months[(ptime->month - 1)]);
|
| + APPEND(' ');
|
| + APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
|
| + APPEND(' ');
|
| + APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
|
| + APPEND(':');
|
| + APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
|
| + APPEND(':');
|
| + APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
|
| + APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
|
| + PNG_UNUSED (pos)
|
| +
|
| +# undef APPEND
|
| +# undef APPEND_NUMBER
|
| +# undef APPEND_STRING
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +# if PNG_LIBPNG_VER < 10700
|
| +/* To do: remove the following from libpng-1.7 */
|
| +/* Original API that uses a private buffer in png_struct.
|
| + * Deprecated because it causes png_struct to carry a spurious temporary
|
| + * buffer (png_struct::time_buffer), better to have the caller pass this in.
|
| + */
|
| +png_const_charp PNGAPI
|
| +png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
|
| +{
|
| + if (png_ptr != NULL)
|
| + {
|
| + /* The only failure above if png_ptr != NULL is from an invalid ptime */
|
| + if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
|
| + png_warning(png_ptr, "Ignoring invalid time value");
|
| +
|
| + else
|
| + return png_ptr->time_buffer;
|
| + }
|
| +
|
| + return NULL;
|
| +}
|
| +# endif /* LIBPNG_VER < 10700 */
|
| +# endif /* TIME_RFC1123 */
|
| +
|
| +#endif /* READ || WRITE */
|
| +
|
| +png_const_charp PNGAPI
|
| +png_get_copyright(png_const_structrp png_ptr)
|
| +{
|
| + PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
|
| +#ifdef PNG_STRING_COPYRIGHT
|
| + return PNG_STRING_COPYRIGHT
|
| +#else
|
| +# ifdef __STDC__
|
| + return PNG_STRING_NEWLINE \
|
| + "libpng version 1.6.20 - December 3, 2015" PNG_STRING_NEWLINE \
|
| + "Copyright (c) 1998-2015 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
|
| + "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
|
| + "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
|
| + PNG_STRING_NEWLINE;
|
| +# else
|
| + return "libpng version 1.6.20 - December 3, 2015\
|
| + Copyright (c) 1998-2015 Glenn Randers-Pehrson\
|
| + Copyright (c) 1996-1997 Andreas Dilger\
|
| + Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
|
| +# endif
|
| +#endif
|
| +}
|
| +
|
| +/* The following return the library version as a short string in the
|
| + * format 1.0.0 through 99.99.99zz. To get the version of *.h files
|
| + * used with your application, print out PNG_LIBPNG_VER_STRING, which
|
| + * is defined in png.h.
|
| + * Note: now there is no difference between png_get_libpng_ver() and
|
| + * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
|
| + * it is guaranteed that png.c uses the correct version of png.h.
|
| + */
|
| +png_const_charp PNGAPI
|
| +png_get_libpng_ver(png_const_structrp png_ptr)
|
| +{
|
| + /* Version of *.c files used when building libpng */
|
| + return png_get_header_ver(png_ptr);
|
| +}
|
| +
|
| +png_const_charp PNGAPI
|
| +png_get_header_ver(png_const_structrp png_ptr)
|
| +{
|
| + /* Version of *.h files used when building libpng */
|
| + PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
|
| + return PNG_LIBPNG_VER_STRING;
|
| +}
|
| +
|
| +png_const_charp PNGAPI
|
| +png_get_header_version(png_const_structrp png_ptr)
|
| +{
|
| + /* Returns longer string containing both version and date */
|
| + PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
|
| +#ifdef __STDC__
|
| + return PNG_HEADER_VERSION_STRING
|
| +# ifndef PNG_READ_SUPPORTED
|
| + " (NO READ SUPPORT)"
|
| +# endif
|
| + PNG_STRING_NEWLINE;
|
| +#else
|
| + return PNG_HEADER_VERSION_STRING;
|
| +#endif
|
| +}
|
| +
|
| +#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
|
| +/* NOTE: this routine is not used internally! */
|
| +/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
|
| + * large of png_color. This lets grayscale images be treated as
|
| + * paletted. Most useful for gamma correction and simplification
|
| + * of code. This API is not used internally.
|
| + */
|
| +void PNGAPI
|
| +png_build_grayscale_palette(int bit_depth, png_colorp palette)
|
| +{
|
| + int num_palette;
|
| + int color_inc;
|
| + int i;
|
| + int v;
|
| +
|
| + png_debug(1, "in png_do_build_grayscale_palette");
|
| +
|
| + if (palette == NULL)
|
| + return;
|
| +
|
| + switch (bit_depth)
|
| + {
|
| + case 1:
|
| + num_palette = 2;
|
| + color_inc = 0xff;
|
| + break;
|
| +
|
| + case 2:
|
| + num_palette = 4;
|
| + color_inc = 0x55;
|
| + break;
|
| +
|
| + case 4:
|
| + num_palette = 16;
|
| + color_inc = 0x11;
|
| + break;
|
| +
|
| + case 8:
|
| + num_palette = 256;
|
| + color_inc = 1;
|
| + break;
|
| +
|
| + default:
|
| + num_palette = 0;
|
| + color_inc = 0;
|
| + break;
|
| + }
|
| +
|
| + for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
|
| + {
|
| + palette[i].red = (png_byte)(v & 0xff);
|
| + palette[i].green = (png_byte)(v & 0xff);
|
| + palette[i].blue = (png_byte)(v & 0xff);
|
| + }
|
| +}
|
| +#endif
|
| +
|
| +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
|
| +int PNGAPI
|
| +png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
|
| +{
|
| + /* Check chunk_name and return "keep" value if it's on the list, else 0 */
|
| + png_const_bytep p, p_end;
|
| +
|
| + if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
|
| + return PNG_HANDLE_CHUNK_AS_DEFAULT;
|
| +
|
| + p_end = png_ptr->chunk_list;
|
| + p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
|
| +
|
| + /* The code is the fifth byte after each four byte string. Historically this
|
| + * code was always searched from the end of the list, this is no longer
|
| + * necessary because the 'set' routine handles duplicate entries correcty.
|
| + */
|
| + do /* num_chunk_list > 0, so at least one */
|
| + {
|
| + p -= 5;
|
| +
|
| + if (memcmp(chunk_name, p, 4) == 0)
|
| + return p[4];
|
| + }
|
| + while (p > p_end);
|
| +
|
| + /* This means that known chunks should be processed and unknown chunks should
|
| + * be handled according to the value of png_ptr->unknown_default; this can be
|
| + * confusing because, as a result, there are two levels of defaulting for
|
| + * unknown chunks.
|
| + */
|
| + return PNG_HANDLE_CHUNK_AS_DEFAULT;
|
| +}
|
| +
|
| +#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
|
| + defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
|
| +int /* PRIVATE */
|
| +png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
|
| +{
|
| + png_byte chunk_string[5];
|
| +
|
| + PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
|
| + return png_handle_as_unknown(png_ptr, chunk_string);
|
| +}
|
| +#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
|
| +#endif /* SET_UNKNOWN_CHUNKS */
|
| +
|
| +#ifdef PNG_READ_SUPPORTED
|
| +/* This function, added to libpng-1.0.6g, is untested. */
|
| +int PNGAPI
|
| +png_reset_zstream(png_structrp png_ptr)
|
| +{
|
| + if (png_ptr == NULL)
|
| + return Z_STREAM_ERROR;
|
| +
|
| + /* WARNING: this resets the window bits to the maximum! */
|
| + return (inflateReset(&png_ptr->zstream));
|
| +}
|
| +#endif /* READ */
|
| +
|
| +/* This function was added to libpng-1.0.7 */
|
| +png_uint_32 PNGAPI
|
| +png_access_version_number(void)
|
| +{
|
| + /* Version of *.c files used when building libpng */
|
| + return((png_uint_32)PNG_LIBPNG_VER);
|
| +}
|
| +
|
| +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
|
| +/* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
|
| + * If it doesn't 'ret' is used to set it to something appropriate, even in cases
|
| + * like Z_OK or Z_STREAM_END where the error code is apparently a success code.
|
| + */
|
| +void /* PRIVATE */
|
| +png_zstream_error(png_structrp png_ptr, int ret)
|
| +{
|
| + /* Translate 'ret' into an appropriate error string, priority is given to the
|
| + * one in zstream if set. This always returns a string, even in cases like
|
| + * Z_OK or Z_STREAM_END where the error code is a success code.
|
| + */
|
| + if (png_ptr->zstream.msg == NULL) switch (ret)
|
| + {
|
| + default:
|
| + case Z_OK:
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
|
| + break;
|
| +
|
| + case Z_STREAM_END:
|
| + /* Normal exit */
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
|
| + break;
|
| +
|
| + case Z_NEED_DICT:
|
| + /* This means the deflate stream did not have a dictionary; this
|
| + * indicates a bogus PNG.
|
| + */
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
|
| + break;
|
| +
|
| + case Z_ERRNO:
|
| + /* gz APIs only: should not happen */
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error");
|
| + break;
|
| +
|
| + case Z_STREAM_ERROR:
|
| + /* internal libpng error */
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib");
|
| + break;
|
| +
|
| + case Z_DATA_ERROR:
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream");
|
| + break;
|
| +
|
| + case Z_MEM_ERROR:
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory");
|
| + break;
|
| +
|
| + case Z_BUF_ERROR:
|
| + /* End of input or output; not a problem if the caller is doing
|
| + * incremental read or write.
|
| + */
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated");
|
| + break;
|
| +
|
| + case Z_VERSION_ERROR:
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version");
|
| + break;
|
| +
|
| + case PNG_UNEXPECTED_ZLIB_RETURN:
|
| + /* Compile errors here mean that zlib now uses the value co-opted in
|
| + * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above
|
| + * and change pngpriv.h. Note that this message is "... return",
|
| + * whereas the default/Z_OK one is "... return code".
|
| + */
|
| + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return");
|
| + break;
|
| + }
|
| +}
|
| +
|
| +/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
|
| + * at libpng 1.5.5!
|
| + */
|
| +
|
| +/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
|
| +#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */
|
| +static int
|
| +png_colorspace_check_gamma(png_const_structrp png_ptr,
|
| + png_colorspacerp colorspace, png_fixed_point gAMA, int from)
|
| + /* This is called to check a new gamma value against an existing one. The
|
| + * routine returns false if the new gamma value should not be written.
|
| + *
|
| + * 'from' says where the new gamma value comes from:
|
| + *
|
| + * 0: the new gamma value is the libpng estimate for an ICC profile
|
| + * 1: the new gamma value comes from a gAMA chunk
|
| + * 2: the new gamma value comes from an sRGB chunk
|
| + */
|
| +{
|
| + png_fixed_point gtest;
|
| +
|
| + if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
|
| + (png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) == 0 ||
|
| + png_gamma_significant(gtest) != 0))
|
| + {
|
| + /* Either this is an sRGB image, in which case the calculated gamma
|
| + * approximation should match, or this is an image with a profile and the
|
| + * value libpng calculates for the gamma of the profile does not match the
|
| + * value recorded in the file. The former, sRGB, case is an error, the
|
| + * latter is just a warning.
|
| + */
|
| + if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2)
|
| + {
|
| + png_chunk_report(png_ptr, "gamma value does not match sRGB",
|
| + PNG_CHUNK_ERROR);
|
| + /* Do not overwrite an sRGB value */
|
| + return from == 2;
|
| + }
|
| +
|
| + else /* sRGB tag not involved */
|
| + {
|
| + png_chunk_report(png_ptr, "gamma value does not match libpng estimate",
|
| + PNG_CHUNK_WARNING);
|
| + return from == 1;
|
| + }
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +void /* PRIVATE */
|
| +png_colorspace_set_gamma(png_const_structrp png_ptr,
|
| + png_colorspacerp colorspace, png_fixed_point gAMA)
|
| +{
|
| + /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
|
| + * occur. Since the fixed point representation is asymetrical it is
|
| + * possible for 1/gamma to overflow the limit of 21474 and this means the
|
| + * gamma value must be at least 5/100000 and hence at most 20000.0. For
|
| + * safety the limits here are a little narrower. The values are 0.00016 to
|
| + * 6250.0, which are truly ridiculous gamma values (and will produce
|
| + * displays that are all black or all white.)
|
| + *
|
| + * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk
|
| + * handling code, which only required the value to be >0.
|
| + */
|
| + png_const_charp errmsg;
|
| +
|
| + if (gAMA < 16 || gAMA > 625000000)
|
| + errmsg = "gamma value out of range";
|
| +
|
| +# ifdef PNG_READ_gAMA_SUPPORTED
|
| + /* Allow the application to set the gamma value more than once */
|
| + else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
|
| + (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
|
| + errmsg = "duplicate";
|
| +# endif
|
| +
|
| + /* Do nothing if the colorspace is already invalid */
|
| + else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
|
| + return;
|
| +
|
| + else
|
| + {
|
| + if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA,
|
| + 1/*from gAMA*/) != 0)
|
| + {
|
| + /* Store this gamma value. */
|
| + colorspace->gamma = gAMA;
|
| + colorspace->flags |=
|
| + (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA);
|
| + }
|
| +
|
| + /* At present if the check_gamma test fails the gamma of the colorspace is
|
| + * not updated however the colorspace is not invalidated. This
|
| + * corresponds to the case where the existing gamma comes from an sRGB
|
| + * chunk or profile. An error message has already been output.
|
| + */
|
| + return;
|
| + }
|
| +
|
| + /* Error exit - errmsg has been set. */
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| + png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR);
|
| +}
|
| +
|
| +void /* PRIVATE */
|
| +png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
|
| +{
|
| + if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
|
| + {
|
| + /* Everything is invalid */
|
| + info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
|
| + PNG_INFO_iCCP);
|
| +
|
| +# ifdef PNG_COLORSPACE_SUPPORTED
|
| + /* Clean up the iCCP profile now if it won't be used. */
|
| + png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
|
| +# else
|
| + PNG_UNUSED(png_ptr)
|
| +# endif
|
| + }
|
| +
|
| + else
|
| + {
|
| +# ifdef PNG_COLORSPACE_SUPPORTED
|
| + /* Leave the INFO_iCCP flag set if the pngset.c code has already set
|
| + * it; this allows a PNG to contain a profile which matches sRGB and
|
| + * yet still have that profile retrievable by the application.
|
| + */
|
| + if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
|
| + info_ptr->valid |= PNG_INFO_sRGB;
|
| +
|
| + else
|
| + info_ptr->valid &= ~PNG_INFO_sRGB;
|
| +
|
| + if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
|
| + info_ptr->valid |= PNG_INFO_cHRM;
|
| +
|
| + else
|
| + info_ptr->valid &= ~PNG_INFO_cHRM;
|
| +# endif
|
| +
|
| + if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
|
| + info_ptr->valid |= PNG_INFO_gAMA;
|
| +
|
| + else
|
| + info_ptr->valid &= ~PNG_INFO_gAMA;
|
| + }
|
| +}
|
| +
|
| +#ifdef PNG_READ_SUPPORTED
|
| +void /* PRIVATE */
|
| +png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
|
| +{
|
| + if (info_ptr == NULL) /* reduce code size; check here not in the caller */
|
| + return;
|
| +
|
| + info_ptr->colorspace = png_ptr->colorspace;
|
| + png_colorspace_sync_info(png_ptr, info_ptr);
|
| +}
|
| +#endif
|
| +#endif /* GAMMA */
|
| +
|
| +#ifdef PNG_COLORSPACE_SUPPORTED
|
| +/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
|
| + * cHRM, as opposed to using chromaticities. These internal APIs return
|
| + * non-zero on a parameter error. The X, Y and Z values are required to be
|
| + * positive and less than 1.0.
|
| + */
|
| +static int
|
| +png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
|
| +{
|
| + png_int_32 d, dwhite, whiteX, whiteY;
|
| +
|
| + d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
|
| + if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0)
|
| + return 1;
|
| + if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0)
|
| + return 1;
|
| + dwhite = d;
|
| + whiteX = XYZ->red_X;
|
| + whiteY = XYZ->red_Y;
|
| +
|
| + d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
|
| + if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0)
|
| + return 1;
|
| + if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0)
|
| + return 1;
|
| + dwhite += d;
|
| + whiteX += XYZ->green_X;
|
| + whiteY += XYZ->green_Y;
|
| +
|
| + d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
|
| + if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0)
|
| + return 1;
|
| + if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0)
|
| + return 1;
|
| + dwhite += d;
|
| + whiteX += XYZ->blue_X;
|
| + whiteY += XYZ->blue_Y;
|
| +
|
| + /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
|
| + * thus:
|
| + */
|
| + if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0)
|
| + return 1;
|
| + if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0)
|
| + return 1;
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +static int
|
| +png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
|
| +{
|
| + png_fixed_point red_inverse, green_inverse, blue_scale;
|
| + png_fixed_point left, right, denominator;
|
| +
|
| + /* Check xy and, implicitly, z. Note that wide gamut color spaces typically
|
| + * have end points with 0 tristimulus values (these are impossible end
|
| + * points, but they are used to cover the possible colors). We check
|
| + * xy->whitey against 5, not 0, to avoid a possible integer overflow.
|
| + */
|
| + if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1;
|
| + if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
|
| + if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
|
| + if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
|
| + if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1;
|
| + if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
|
| + if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
|
| + if (xy->whitey < 5 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
|
| +
|
| + /* The reverse calculation is more difficult because the original tristimulus
|
| + * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
|
| + * derived values were recorded in the cHRM chunk;
|
| + * (red,green,blue,white)x(x,y). This loses one degree of freedom and
|
| + * therefore an arbitrary ninth value has to be introduced to undo the
|
| + * original transformations.
|
| + *
|
| + * Think of the original end-points as points in (X,Y,Z) space. The
|
| + * chromaticity values (c) have the property:
|
| + *
|
| + * C
|
| + * c = ---------
|
| + * X + Y + Z
|
| + *
|
| + * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the
|
| + * three chromaticity values (x,y,z) for each end-point obey the
|
| + * relationship:
|
| + *
|
| + * x + y + z = 1
|
| + *
|
| + * This describes the plane in (X,Y,Z) space that intersects each axis at the
|
| + * value 1.0; call this the chromaticity plane. Thus the chromaticity
|
| + * calculation has scaled each end-point so that it is on the x+y+z=1 plane
|
| + * and chromaticity is the intersection of the vector from the origin to the
|
| + * (X,Y,Z) value with the chromaticity plane.
|
| + *
|
| + * To fully invert the chromaticity calculation we would need the three
|
| + * end-point scale factors, (red-scale, green-scale, blue-scale), but these
|
| + * were not recorded. Instead we calculated the reference white (X,Y,Z) and
|
| + * recorded the chromaticity of this. The reference white (X,Y,Z) would have
|
| + * given all three of the scale factors since:
|
| + *
|
| + * color-C = color-c * color-scale
|
| + * white-C = red-C + green-C + blue-C
|
| + * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
|
| + *
|
| + * But cHRM records only white-x and white-y, so we have lost the white scale
|
| + * factor:
|
| + *
|
| + * white-C = white-c*white-scale
|
| + *
|
| + * To handle this the inverse transformation makes an arbitrary assumption
|
| + * about white-scale:
|
| + *
|
| + * Assume: white-Y = 1.0
|
| + * Hence: white-scale = 1/white-y
|
| + * Or: red-Y + green-Y + blue-Y = 1.0
|
| + *
|
| + * Notice the last statement of the assumption gives an equation in three of
|
| + * the nine values we want to calculate. 8 more equations come from the
|
| + * above routine as summarised at the top above (the chromaticity
|
| + * calculation):
|
| + *
|
| + * Given: color-x = color-X / (color-X + color-Y + color-Z)
|
| + * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
|
| + *
|
| + * This is 9 simultaneous equations in the 9 variables "color-C" and can be
|
| + * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix
|
| + * determinants, however this is not as bad as it seems because only 28 of
|
| + * the total of 90 terms in the various matrices are non-zero. Nevertheless
|
| + * Cramer's rule is notoriously numerically unstable because the determinant
|
| + * calculation involves the difference of large, but similar, numbers. It is
|
| + * difficult to be sure that the calculation is stable for real world values
|
| + * and it is certain that it becomes unstable where the end points are close
|
| + * together.
|
| + *
|
| + * So this code uses the perhaps slightly less optimal but more
|
| + * understandable and totally obvious approach of calculating color-scale.
|
| + *
|
| + * This algorithm depends on the precision in white-scale and that is
|
| + * (1/white-y), so we can immediately see that as white-y approaches 0 the
|
| + * accuracy inherent in the cHRM chunk drops off substantially.
|
| + *
|
| + * libpng arithmetic: a simple inversion of the above equations
|
| + * ------------------------------------------------------------
|
| + *
|
| + * white_scale = 1/white-y
|
| + * white-X = white-x * white-scale
|
| + * white-Y = 1.0
|
| + * white-Z = (1 - white-x - white-y) * white_scale
|
| + *
|
| + * white-C = red-C + green-C + blue-C
|
| + * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
|
| + *
|
| + * This gives us three equations in (red-scale,green-scale,blue-scale) where
|
| + * all the coefficients are now known:
|
| + *
|
| + * red-x*red-scale + green-x*green-scale + blue-x*blue-scale
|
| + * = white-x/white-y
|
| + * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
|
| + * red-z*red-scale + green-z*green-scale + blue-z*blue-scale
|
| + * = (1 - white-x - white-y)/white-y
|
| + *
|
| + * In the last equation color-z is (1 - color-x - color-y) so we can add all
|
| + * three equations together to get an alternative third:
|
| + *
|
| + * red-scale + green-scale + blue-scale = 1/white-y = white-scale
|
| + *
|
| + * So now we have a Cramer's rule solution where the determinants are just
|
| + * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve
|
| + * multiplication of three coefficients so we can't guarantee to avoid
|
| + * overflow in the libpng fixed point representation. Using Cramer's rule in
|
| + * floating point is probably a good choice here, but it's not an option for
|
| + * fixed point. Instead proceed to simplify the first two equations by
|
| + * eliminating what is likely to be the largest value, blue-scale:
|
| + *
|
| + * blue-scale = white-scale - red-scale - green-scale
|
| + *
|
| + * Hence:
|
| + *
|
| + * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
|
| + * (white-x - blue-x)*white-scale
|
| + *
|
| + * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
|
| + * 1 - blue-y*white-scale
|
| + *
|
| + * And now we can trivially solve for (red-scale,green-scale):
|
| + *
|
| + * green-scale =
|
| + * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
|
| + * -----------------------------------------------------------
|
| + * green-x - blue-x
|
| + *
|
| + * red-scale =
|
| + * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale
|
| + * ---------------------------------------------------------
|
| + * red-y - blue-y
|
| + *
|
| + * Hence:
|
| + *
|
| + * red-scale =
|
| + * ( (green-x - blue-x) * (white-y - blue-y) -
|
| + * (green-y - blue-y) * (white-x - blue-x) ) / white-y
|
| + * -------------------------------------------------------------------------
|
| + * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
|
| + *
|
| + * green-scale =
|
| + * ( (red-y - blue-y) * (white-x - blue-x) -
|
| + * (red-x - blue-x) * (white-y - blue-y) ) / white-y
|
| + * -------------------------------------------------------------------------
|
| + * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
|
| + *
|
| + * Accuracy:
|
| + * The input values have 5 decimal digits of accuracy. The values are all in
|
| + * the range 0 < value < 1, so simple products are in the same range but may
|
| + * need up to 10 decimal digits to preserve the original precision and avoid
|
| + * underflow. Because we are using a 32-bit signed representation we cannot
|
| + * match this; the best is a little over 9 decimal digits, less than 10.
|
| + *
|
| + * The approach used here is to preserve the maximum precision within the
|
| + * signed representation. Because the red-scale calculation above uses the
|
| + * difference between two products of values that must be in the range -1..+1
|
| + * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The
|
| + * factor is irrelevant in the calculation because it is applied to both
|
| + * numerator and denominator.
|
| + *
|
| + * Note that the values of the differences of the products of the
|
| + * chromaticities in the above equations tend to be small, for example for
|
| + * the sRGB chromaticities they are:
|
| + *
|
| + * red numerator: -0.04751
|
| + * green numerator: -0.08788
|
| + * denominator: -0.2241 (without white-y multiplication)
|
| + *
|
| + * The resultant Y coefficients from the chromaticities of some widely used
|
| + * color space definitions are (to 15 decimal places):
|
| + *
|
| + * sRGB
|
| + * 0.212639005871510 0.715168678767756 0.072192315360734
|
| + * Kodak ProPhoto
|
| + * 0.288071128229293 0.711843217810102 0.000085653960605
|
| + * Adobe RGB
|
| + * 0.297344975250536 0.627363566255466 0.075291458493998
|
| + * Adobe Wide Gamut RGB
|
| + * 0.258728243040113 0.724682314948566 0.016589442011321
|
| + */
|
| + /* By the argument, above overflow should be impossible here. The return
|
| + * value of 2 indicates an internal error to the caller.
|
| + */
|
| + if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0)
|
| + return 2;
|
| + if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0)
|
| + return 2;
|
| + denominator = left - right;
|
| +
|
| + /* Now find the red numerator. */
|
| + if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
|
| + return 2;
|
| + if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
|
| + return 2;
|
| +
|
| + /* Overflow is possible here and it indicates an extreme set of PNG cHRM
|
| + * chunk values. This calculation actually returns the reciprocal of the
|
| + * scale value because this allows us to delay the multiplication of white-y
|
| + * into the denominator, which tends to produce a small number.
|
| + */
|
| + if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 ||
|
| + red_inverse <= xy->whitey /* r+g+b scales = white scale */)
|
| + return 1;
|
| +
|
| + /* Similarly for green_inverse: */
|
| + if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
|
| + return 2;
|
| + if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
|
| + return 2;
|
| + if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 ||
|
| + green_inverse <= xy->whitey)
|
| + return 1;
|
| +
|
| + /* And the blue scale, the checks above guarantee this can't overflow but it
|
| + * can still produce 0 for extreme cHRM values.
|
| + */
|
| + blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
|
| + png_reciprocal(green_inverse);
|
| + if (blue_scale <= 0)
|
| + return 1;
|
| +
|
| +
|
| + /* And fill in the png_XYZ: */
|
| + if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
|
| + red_inverse) == 0)
|
| + return 1;
|
| +
|
| + if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
|
| + green_inverse) == 0)
|
| + return 1;
|
| +
|
| + if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
|
| + PNG_FP_1) == 0)
|
| + return 1;
|
| +
|
| + return 0; /*success*/
|
| +}
|
| +
|
| +static int
|
| +png_XYZ_normalize(png_XYZ *XYZ)
|
| +{
|
| + png_int_32 Y;
|
| +
|
| + if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 ||
|
| + XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 ||
|
| + XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0)
|
| + return 1;
|
| +
|
| + /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1.
|
| + * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore
|
| + * relying on addition of two positive values producing a negative one is not
|
| + * safe.
|
| + */
|
| + Y = XYZ->red_Y;
|
| + if (0x7fffffff - Y < XYZ->green_X)
|
| + return 1;
|
| + Y += XYZ->green_Y;
|
| + if (0x7fffffff - Y < XYZ->blue_X)
|
| + return 1;
|
| + Y += XYZ->blue_Y;
|
| +
|
| + if (Y != PNG_FP_1)
|
| + {
|
| + if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| +
|
| + if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| +
|
| + if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0)
|
| + return 1;
|
| + }
|
| +
|
| + return 0;
|
| +}
|
| +
|
| +static int
|
| +png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
|
| +{
|
| + /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
|
| + if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) ||
|
| + PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta))
|
| + return 0;
|
| + return 1;
|
| +}
|
| +
|
| +/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
|
| + * chunk chromaticities. Earlier checks used to simply look for the overflow
|
| + * condition (where the determinant of the matrix to solve for XYZ ends up zero
|
| + * because the chromaticity values are not all distinct.) Despite this it is
|
| + * theoretically possible to produce chromaticities that are apparently valid
|
| + * but that rapidly degrade to invalid, potentially crashing, sets because of
|
| + * arithmetic inaccuracies when calculations are performed on them. The new
|
| + * check is to round-trip xy -> XYZ -> xy and then check that the result is
|
| + * within a small percentage of the original.
|
| + */
|
| +static int
|
| +png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)
|
| +{
|
| + int result;
|
| + png_xy xy_test;
|
| +
|
| + /* As a side-effect this routine also returns the XYZ endpoints. */
|
| + result = png_XYZ_from_xy(XYZ, xy);
|
| + if (result != 0)
|
| + return result;
|
| +
|
| + result = png_xy_from_XYZ(&xy_test, XYZ);
|
| + if (result != 0)
|
| + return result;
|
| +
|
| + if (png_colorspace_endpoints_match(xy, &xy_test,
|
| + 5/*actually, the math is pretty accurate*/) != 0)
|
| + return 0;
|
| +
|
| + /* Too much slip */
|
| + return 1;
|
| +}
|
| +
|
| +/* This is the check going the other way. The XYZ is modified to normalize it
|
| + * (another side-effect) and the xy chromaticities are returned.
|
| + */
|
| +static int
|
| +png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
|
| +{
|
| + int result;
|
| + png_XYZ XYZtemp;
|
| +
|
| + result = png_XYZ_normalize(XYZ);
|
| + if (result != 0)
|
| + return result;
|
| +
|
| + result = png_xy_from_XYZ(xy, XYZ);
|
| + if (result != 0)
|
| + return result;
|
| +
|
| + XYZtemp = *XYZ;
|
| + return png_colorspace_check_xy(&XYZtemp, xy);
|
| +}
|
| +
|
| +/* Used to check for an endpoint match against sRGB */
|
| +static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
|
| +{
|
| + /* color x y */
|
| + /* red */ 64000, 33000,
|
| + /* green */ 30000, 60000,
|
| + /* blue */ 15000, 6000,
|
| + /* white */ 31270, 32900
|
| +};
|
| +
|
| +static int
|
| +png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
|
| + png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
|
| + int preferred)
|
| +{
|
| + if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
|
| + return 0;
|
| +
|
| + /* The consistency check is performed on the chromaticities; this factors out
|
| + * variations because of the normalization (or not) of the end point Y
|
| + * values.
|
| + */
|
| + if (preferred < 2 &&
|
| + (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
|
| + {
|
| + /* The end points must be reasonably close to any we already have. The
|
| + * following allows an error of up to +/-.001
|
| + */
|
| + if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy,
|
| + 100) == 0)
|
| + {
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| + png_benign_error(png_ptr, "inconsistent chromaticities");
|
| + return 0; /* failed */
|
| + }
|
| +
|
| + /* Only overwrite with preferred values */
|
| + if (preferred == 0)
|
| + return 1; /* ok, but no change */
|
| + }
|
| +
|
| + colorspace->end_points_xy = *xy;
|
| + colorspace->end_points_XYZ = *XYZ;
|
| + colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS;
|
| +
|
| + /* The end points are normally quoted to two decimal digits, so allow +/-0.01
|
| + * on this test.
|
| + */
|
| + if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0)
|
| + colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;
|
| +
|
| + else
|
| + colorspace->flags &= PNG_COLORSPACE_CANCEL(
|
| + PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
|
| +
|
| + return 2; /* ok and changed */
|
| +}
|
| +
|
| +int /* PRIVATE */
|
| +png_colorspace_set_chromaticities(png_const_structrp png_ptr,
|
| + png_colorspacerp colorspace, const png_xy *xy, int preferred)
|
| +{
|
| + /* We must check the end points to ensure they are reasonable - in the past
|
| + * color management systems have crashed as a result of getting bogus
|
| + * colorant values, while this isn't the fault of libpng it is the
|
| + * responsibility of libpng because PNG carries the bomb and libpng is in a
|
| + * position to protect against it.
|
| + */
|
| + png_XYZ XYZ;
|
| +
|
| + switch (png_colorspace_check_xy(&XYZ, xy))
|
| + {
|
| + case 0: /* success */
|
| + return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ,
|
| + preferred);
|
| +
|
| + case 1:
|
| + /* We can't invert the chromaticities so we can't produce value XYZ
|
| + * values. Likely as not a color management system will fail too.
|
| + */
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| + png_benign_error(png_ptr, "invalid chromaticities");
|
| + break;
|
| +
|
| + default:
|
| + /* libpng is broken; this should be a warning but if it happens we
|
| + * want error reports so for the moment it is an error.
|
| + */
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| + png_error(png_ptr, "internal error checking chromaticities");
|
| + }
|
| +
|
| + return 0; /* failed */
|
| +}
|
| +
|
| +int /* PRIVATE */
|
| +png_colorspace_set_endpoints(png_const_structrp png_ptr,
|
| + png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred)
|
| +{
|
| + png_XYZ XYZ = *XYZ_in;
|
| + png_xy xy;
|
| +
|
| + switch (png_colorspace_check_XYZ(&xy, &XYZ))
|
| + {
|
| + case 0:
|
| + return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ,
|
| + preferred);
|
| +
|
| + case 1:
|
| + /* End points are invalid. */
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| + png_benign_error(png_ptr, "invalid end points");
|
| + break;
|
| +
|
| + default:
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| + png_error(png_ptr, "internal error checking chromaticities");
|
| + }
|
| +
|
| + return 0; /* failed */
|
| +}
|
| +
|
| +#if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED)
|
| +/* Error message generation */
|
| +static char
|
| +png_icc_tag_char(png_uint_32 byte)
|
| +{
|
| + byte &= 0xff;
|
| + if (byte >= 32 && byte <= 126)
|
| + return (char)byte;
|
| + else
|
| + return '?';
|
| +}
|
| +
|
| +static void
|
| +png_icc_tag_name(char *name, png_uint_32 tag)
|
| +{
|
| + name[0] = '\'';
|
| + name[1] = png_icc_tag_char(tag >> 24);
|
| + name[2] = png_icc_tag_char(tag >> 16);
|
| + name[3] = png_icc_tag_char(tag >> 8);
|
| + name[4] = png_icc_tag_char(tag );
|
| + name[5] = '\'';
|
| +}
|
| +
|
| +static int
|
| +is_ICC_signature_char(png_alloc_size_t it)
|
| +{
|
| + return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) ||
|
| + (it >= 97 && it <= 122);
|
| +}
|
| +
|
| +static int
|
| +is_ICC_signature(png_alloc_size_t it)
|
| +{
|
| + return is_ICC_signature_char(it >> 24) /* checks all the top bits */ &&
|
| + is_ICC_signature_char((it >> 16) & 0xff) &&
|
| + is_ICC_signature_char((it >> 8) & 0xff) &&
|
| + is_ICC_signature_char(it & 0xff);
|
| +}
|
| +
|
| +static int
|
| +png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| + png_const_charp name, png_alloc_size_t value, png_const_charp reason)
|
| +{
|
| + size_t pos;
|
| + char message[196]; /* see below for calculation */
|
| +
|
| + if (colorspace != NULL)
|
| + colorspace->flags |= PNG_COLORSPACE_INVALID;
|
| +
|
| + pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
|
| + pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
|
| + pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
|
| + if (is_ICC_signature(value) != 0)
|
| + {
|
| + /* So 'value' is at most 4 bytes and the following cast is safe */
|
| + png_icc_tag_name(message+pos, (png_uint_32)value);
|
| + pos += 6; /* total +8; less than the else clause */
|
| + message[pos++] = ':';
|
| + message[pos++] = ' ';
|
| + }
|
| +# ifdef PNG_WARNINGS_SUPPORTED
|
| + else
|
| + {
|
| + char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/
|
| +
|
| + pos = png_safecat(message, (sizeof message), pos,
|
| + png_format_number(number, number+(sizeof number),
|
| + PNG_NUMBER_FORMAT_x, value));
|
| + pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/
|
| + }
|
| +# endif
|
| + /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
|
| + pos = png_safecat(message, (sizeof message), pos, reason);
|
| + PNG_UNUSED(pos)
|
| +
|
| + /* This is recoverable, but make it unconditionally an app_error on write to
|
| + * avoid writing invalid ICC profiles into PNG files (i.e., we handle them
|
| + * on read, with a warning, but on write unless the app turns off
|
| + * application errors the PNG won't be written.)
|
| + */
|
| + png_chunk_report(png_ptr, message,
|
| + (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR);
|
| +
|
| + return 0;
|
| +}
|
| +#endif /* sRGB || iCCP */
|
| +
|
| +#ifdef PNG_sRGB_SUPPORTED
|
| +int /* PRIVATE */
|
| +png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| + int intent)
|
| +{
|
| + /* sRGB sets known gamma, end points and (from the chunk) intent. */
|
| + /* IMPORTANT: these are not necessarily the values found in an ICC profile
|
| + * because ICC profiles store values adapted to a D50 environment; it is
|
| + * expected that the ICC profile mediaWhitePointTag will be D50; see the
|
| + * checks and code elsewhere to understand this better.
|
| + *
|
| + * These XYZ values, which are accurate to 5dp, produce rgb to gray
|
| + * coefficients of (6968,23435,2366), which are reduced (because they add up
|
| + * to 32769 not 32768) to (6968,23434,2366). These are the values that
|
| + * libpng has traditionally used (and are the best values given the 15bit
|
| + * algorithm used by the rgb to gray code.)
|
| + */
|
| + static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */
|
| + {
|
| + /* color X Y Z */
|
| + /* red */ 41239, 21264, 1933,
|
| + /* green */ 35758, 71517, 11919,
|
| + /* blue */ 18048, 7219, 95053
|
| + };
|
| +
|
| + /* Do nothing if the colorspace is already invalidated. */
|
| + if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
|
| + return 0;
|
| +
|
| + /* Check the intent, then check for existing settings. It is valid for the
|
| + * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must
|
| + * be consistent with the correct values. If, however, this function is
|
| + * called below because an iCCP chunk matches sRGB then it is quite
|
| + * conceivable that an older app recorded incorrect gAMA and cHRM because of
|
| + * an incorrect calculation based on the values in the profile - this does
|
| + * *not* invalidate the profile (though it still produces an error, which can
|
| + * be ignored.)
|
| + */
|
| + if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
|
| + return png_icc_profile_error(png_ptr, colorspace, "sRGB",
|
| + (unsigned)intent, "invalid sRGB rendering intent");
|
| +
|
| + if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
|
| + colorspace->rendering_intent != intent)
|
| + return png_icc_profile_error(png_ptr, colorspace, "sRGB",
|
| + (unsigned)intent, "inconsistent rendering intents");
|
| +
|
| + if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
|
| + {
|
| + png_benign_error(png_ptr, "duplicate sRGB information ignored");
|
| + return 0;
|
| + }
|
| +
|
| + /* If the standard sRGB cHRM chunk does not match the one from the PNG file
|
| + * warn but overwrite the value with the correct one.
|
| + */
|
| + if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 &&
|
| + !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy,
|
| + 100))
|
| + png_chunk_report(png_ptr, "cHRM chunk does not match sRGB",
|
| + PNG_CHUNK_ERROR);
|
| +
|
| + /* This check is just done for the error reporting - the routine always
|
| + * returns true when the 'from' argument corresponds to sRGB (2).
|
| + */
|
| + (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE,
|
| + 2/*from sRGB*/);
|
| +
|
| + /* intent: bugs in GCC force 'int' to be used as the parameter type. */
|
| + colorspace->rendering_intent = (png_uint_16)intent;
|
| + colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT;
|
| +
|
| + /* endpoints */
|
| + colorspace->end_points_xy = sRGB_xy;
|
| + colorspace->end_points_XYZ = sRGB_XYZ;
|
| + colorspace->flags |=
|
| + (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
|
| +
|
| + /* gamma */
|
| + colorspace->gamma = PNG_GAMMA_sRGB_INVERSE;
|
| + colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
| +
|
| + /* Finally record that we have an sRGB profile */
|
| + colorspace->flags |=
|
| + (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB);
|
| +
|
| + return 1; /* set */
|
| +}
|
| +#endif /* sRGB */
|
| +
|
| +#ifdef PNG_iCCP_SUPPORTED
|
| +/* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value
|
| + * is XYZ(0.9642,1.0,0.8249), which scales to:
|
| + *
|
| + * (63189.8112, 65536, 54060.6464)
|
| + */
|
| +static const png_byte D50_nCIEXYZ[12] =
|
| + { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d };
|
| +
|
| +int /* PRIVATE */
|
| +png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| + png_const_charp name, png_uint_32 profile_length)
|
| +{
|
| + if (profile_length < 132)
|
| + return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
|
| + "too short");
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +int /* PRIVATE */
|
| +png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| + png_const_charp name, png_uint_32 profile_length,
|
| + png_const_bytep profile/* first 132 bytes only */, int color_type)
|
| +{
|
| + png_uint_32 temp;
|
| +
|
| + /* Length check; this cannot be ignored in this code because profile_length
|
| + * is used later to check the tag table, so even if the profile seems over
|
| + * long profile_length from the caller must be correct. The caller can fix
|
| + * this up on read or write by just passing in the profile header length.
|
| + */
|
| + temp = png_get_uint_32(profile);
|
| + if (temp != profile_length)
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "length does not match profile");
|
| +
|
| + temp = (png_uint_32) (*(profile+8));
|
| + if (temp > 3 && (profile_length & 3))
|
| + return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
|
| + "invalid length");
|
| +
|
| + temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */
|
| + if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */
|
| + profile_length < 132+12*temp) /* truncated tag table */
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "tag count too large");
|
| +
|
| + /* The 'intent' must be valid or we can't store it, ICC limits the intent to
|
| + * 16 bits.
|
| + */
|
| + temp = png_get_uint_32(profile+64);
|
| + if (temp >= 0xffff) /* The ICC limit */
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "invalid rendering intent");
|
| +
|
| + /* This is just a warning because the profile may be valid in future
|
| + * versions.
|
| + */
|
| + if (temp >= PNG_sRGB_INTENT_LAST)
|
| + (void)png_icc_profile_error(png_ptr, NULL, name, temp,
|
| + "intent outside defined range");
|
| +
|
| + /* At this point the tag table can't be checked because it hasn't necessarily
|
| + * been loaded; however, various header fields can be checked. These checks
|
| + * are for values permitted by the PNG spec in an ICC profile; the PNG spec
|
| + * restricts the profiles that can be passed in an iCCP chunk (they must be
|
| + * appropriate to processing PNG data!)
|
| + */
|
| +
|
| + /* Data checks (could be skipped). These checks must be independent of the
|
| + * version number; however, the version number doesn't accomodate changes in
|
| + * the header fields (just the known tags and the interpretation of the
|
| + * data.)
|
| + */
|
| + temp = png_get_uint_32(profile+36); /* signature 'ascp' */
|
| + if (temp != 0x61637370)
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "invalid signature");
|
| +
|
| + /* Currently the PCS illuminant/adopted white point (the computational
|
| + * white point) are required to be D50,
|
| + * however the profile contains a record of the illuminant so perhaps ICC
|
| + * expects to be able to change this in the future (despite the rationale in
|
| + * the introduction for using a fixed PCS adopted white.) Consequently the
|
| + * following is just a warning.
|
| + */
|
| + if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0)
|
| + (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/,
|
| + "PCS illuminant is not D50");
|
| +
|
| + /* The PNG spec requires this:
|
| + * "If the iCCP chunk is present, the image samples conform to the colour
|
| + * space represented by the embedded ICC profile as defined by the
|
| + * International Color Consortium [ICC]. The colour space of the ICC profile
|
| + * shall be an RGB colour space for colour images (PNG colour types 2, 3, and
|
| + * 6), or a greyscale colour space for greyscale images (PNG colour types 0
|
| + * and 4)."
|
| + *
|
| + * This checking code ensures the embedded profile (on either read or write)
|
| + * conforms to the specification requirements. Notice that an ICC 'gray'
|
| + * color-space profile contains the information to transform the monochrome
|
| + * data to XYZ or L*a*b (according to which PCS the profile uses) and this
|
| + * should be used in preference to the standard libpng K channel replication
|
| + * into R, G and B channels.
|
| + *
|
| + * Previously it was suggested that an RGB profile on grayscale data could be
|
| + * handled. However it it is clear that using an RGB profile in this context
|
| + * must be an error - there is no specification of what it means. Thus it is
|
| + * almost certainly more correct to ignore the profile.
|
| + */
|
| + temp = png_get_uint_32(profile+16); /* data colour space field */
|
| + switch (temp)
|
| + {
|
| + case 0x52474220: /* 'RGB ' */
|
| + if ((color_type & PNG_COLOR_MASK_COLOR) == 0)
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "RGB color space not permitted on grayscale PNG");
|
| + break;
|
| +
|
| + case 0x47524159: /* 'GRAY' */
|
| + if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "Gray color space not permitted on RGB PNG");
|
| + break;
|
| +
|
| + default:
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "invalid ICC profile color space");
|
| + }
|
| +
|
| + /* It is up to the application to check that the profile class matches the
|
| + * application requirements; the spec provides no guidance, but it's pretty
|
| + * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer
|
| + * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these
|
| + * cases. Issue an error for device link or abstract profiles - these don't
|
| + * contain the records necessary to transform the color-space to anything
|
| + * other than the target device (and not even that for an abstract profile).
|
| + * Profiles of these classes may not be embedded in images.
|
| + */
|
| + temp = png_get_uint_32(profile+12); /* profile/device class */
|
| + switch (temp)
|
| + {
|
| + case 0x73636e72: /* 'scnr' */
|
| + case 0x6d6e7472: /* 'mntr' */
|
| + case 0x70727472: /* 'prtr' */
|
| + case 0x73706163: /* 'spac' */
|
| + /* All supported */
|
| + break;
|
| +
|
| + case 0x61627374: /* 'abst' */
|
| + /* May not be embedded in an image */
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "invalid embedded Abstract ICC profile");
|
| +
|
| + case 0x6c696e6b: /* 'link' */
|
| + /* DeviceLink profiles cannot be interpreted in a non-device specific
|
| + * fashion, if an app uses the AToB0Tag in the profile the results are
|
| + * undefined unless the result is sent to the intended device,
|
| + * therefore a DeviceLink profile should not be found embedded in a
|
| + * PNG.
|
| + */
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "unexpected DeviceLink ICC profile class");
|
| +
|
| + case 0x6e6d636c: /* 'nmcl' */
|
| + /* A NamedColor profile is also device specific, however it doesn't
|
| + * contain an AToB0 tag that is open to misinterpretation. Almost
|
| + * certainly it will fail the tests below.
|
| + */
|
| + (void)png_icc_profile_error(png_ptr, NULL, name, temp,
|
| + "unexpected NamedColor ICC profile class");
|
| + break;
|
| +
|
| + default:
|
| + /* To allow for future enhancements to the profile accept unrecognized
|
| + * profile classes with a warning, these then hit the test below on the
|
| + * tag content to ensure they are backward compatible with one of the
|
| + * understood profiles.
|
| + */
|
| + (void)png_icc_profile_error(png_ptr, NULL, name, temp,
|
| + "unrecognized ICC profile class");
|
| + break;
|
| + }
|
| +
|
| + /* For any profile other than a device link one the PCS must be encoded
|
| + * either in XYZ or Lab.
|
| + */
|
| + temp = png_get_uint_32(profile+20);
|
| + switch (temp)
|
| + {
|
| + case 0x58595a20: /* 'XYZ ' */
|
| + case 0x4c616220: /* 'Lab ' */
|
| + break;
|
| +
|
| + default:
|
| + return png_icc_profile_error(png_ptr, colorspace, name, temp,
|
| + "unexpected ICC PCS encoding");
|
| + }
|
| +
|
| + return 1;
|
| +}
|
| +
|
| +int /* PRIVATE */
|
| +png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| + png_const_charp name, png_uint_32 profile_length,
|
| + png_const_bytep profile /* header plus whole tag table */)
|
| +{
|
| + png_uint_32 tag_count = png_get_uint_32(profile+128);
|
| + png_uint_32 itag;
|
| + png_const_bytep tag = profile+132; /* The first tag */
|
| +
|
| + /* First scan all the tags in the table and add bits to the icc_info value
|
| + * (temporarily in 'tags').
|
| + */
|
| + for (itag=0; itag < tag_count; ++itag, tag += 12)
|
| + {
|
| + png_uint_32 tag_id = png_get_uint_32(tag+0);
|
| + png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */
|
| + png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */
|
| +
|
| + /* The ICC specification does not exclude zero length tags, therefore the
|
| + * start might actually be anywhere if there is no data, but this would be
|
| + * a clear abuse of the intent of the standard so the start is checked for
|
| + * being in range. All defined tag types have an 8 byte header - a 4 byte
|
| + * type signature then 0.
|
| + */
|
| + if ((tag_start & 3) != 0)
|
| + {
|
| + /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is
|
| + * only a warning here because libpng does not care about the
|
| + * alignment.
|
| + */
|
| + (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
|
| + "ICC profile tag start not a multiple of 4");
|
| + }
|
| +
|
| + /* This is a hard error; potentially it can cause read outside the
|
| + * profile.
|
| + */
|
| + if (tag_start > profile_length || tag_length > profile_length - tag_start)
|
| + return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
|
| + "ICC profile tag outside profile");
|
| + }
|
| +
|
| + return 1; /* success, maybe with warnings */
|
| +}
|
| +
|
| +#ifdef PNG_sRGB_SUPPORTED
|
| +#if PNG_sRGB_PROFILE_CHECKS >= 0
|
| +/* Information about the known ICC sRGB profiles */
|
| +static const struct
|
| +{
|
| + png_uint_32 adler, crc, length;
|
| + png_uint_32 md5[4];
|
| + png_byte have_md5;
|
| + png_byte is_broken;
|
| + png_uint_16 intent;
|
| +
|
| +# define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0)
|
| +# define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\
|
| + { adler, crc, length, md5, broke, intent },
|
| +
|
| +} png_sRGB_checks[] =
|
| +{
|
| + /* This data comes from contrib/tools/checksum-icc run on downloads of
|
| + * all four ICC sRGB profiles from www.color.org.
|
| + */
|
| + /* adler32, crc32, MD5[4], intent, date, length, file-name */
|
| + PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9,
|
| + PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0,
|
| + "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc")
|
| +
|
| + /* ICC sRGB v2 perceptual no black-compensation: */
|
| + PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21,
|
| + PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0,
|
| + "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc")
|
| +
|
| + PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae,
|
| + PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0,
|
| + "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc")
|
| +
|
| + /* ICC sRGB v4 perceptual */
|
| + PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812,
|
| + PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0,
|
| + "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc")
|
| +
|
| + /* The following profiles have no known MD5 checksum. If there is a match
|
| + * on the (empty) MD5 the other fields are used to attempt a match and
|
| + * a warning is produced. The first two of these profiles have a 'cprt' tag
|
| + * which suggests that they were also made by Hewlett Packard.
|
| + */
|
| + PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce,
|
| + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0,
|
| + "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc")
|
| +
|
| + /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not
|
| + * match the D50 PCS illuminant in the header (it is in fact the D65 values,
|
| + * so the white point is recorded as the un-adapted value.) The profiles
|
| + * below only differ in one byte - the intent - and are basically the same as
|
| + * the previous profile except for the mediaWhitePointTag error and a missing
|
| + * chromaticAdaptationTag.
|
| + */
|
| + PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552,
|
| + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/,
|
| + "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual")
|
| +
|
| + PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d,
|
| + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/,
|
| + "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative")
|
| +};
|
| +
|
| +static int
|
| +png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
|
| + png_const_bytep profile, uLong adler)
|
| +{
|
| + /* The quick check is to verify just the MD5 signature and trust the
|
| + * rest of the data. Because the profile has already been verified for
|
| + * correctness this is safe. png_colorspace_set_sRGB will check the 'intent'
|
| + * field too, so if the profile has been edited with an intent not defined
|
| + * by sRGB (but maybe defined by a later ICC specification) the read of
|
| + * the profile will fail at that point.
|
| + */
|
| +
|
| + png_uint_32 length = 0;
|
| + png_uint_32 intent = 0x10000; /* invalid */
|
| +#if PNG_sRGB_PROFILE_CHECKS > 1
|
| + uLong crc = 0; /* the value for 0 length data */
|
| +#endif
|
| + unsigned int i;
|
| +
|
| +#ifdef PNG_SET_OPTION_SUPPORTED
|
| + /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
|
| + if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
|
| + PNG_OPTION_ON)
|
| + return 0;
|
| +#endif
|
| +
|
| + for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
|
| + {
|
| + if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
|
| + png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] &&
|
| + png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] &&
|
| + png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3])
|
| + {
|
| + /* This may be one of the old HP profiles without an MD5, in that
|
| + * case we can only use the length and Adler32 (note that these
|
| + * are not used by default if there is an MD5!)
|
| + */
|
| +# if PNG_sRGB_PROFILE_CHECKS == 0
|
| + if (png_sRGB_checks[i].have_md5 != 0)
|
| + return 1+png_sRGB_checks[i].is_broken;
|
| +# endif
|
| +
|
| + /* Profile is unsigned or more checks have been configured in. */
|
| + if (length == 0)
|
| + {
|
| + length = png_get_uint_32(profile);
|
| + intent = png_get_uint_32(profile+64);
|
| + }
|
| +
|
| + /* Length *and* intent must match */
|
| + if (length == (png_uint_32) png_sRGB_checks[i].length &&
|
| + intent == (png_uint_32) png_sRGB_checks[i].intent)
|
| + {
|
| + /* Now calculate the adler32 if not done already. */
|
| + if (adler == 0)
|
| + {
|
| + adler = adler32(0, NULL, 0);
|
| + adler = adler32(adler, profile, length);
|
| + }
|
| +
|
| + if (adler == png_sRGB_checks[i].adler)
|
| + {
|
| + /* These basic checks suggest that the data has not been
|
| + * modified, but if the check level is more than 1 perform
|
| + * our own crc32 checksum on the data.
|
| + */
|
| +# if PNG_sRGB_PROFILE_CHECKS > 1
|
| + if (crc == 0)
|
| + {
|
| + crc = crc32(0, NULL, 0);
|
| + crc = crc32(crc, profile, length);
|
| + }
|
| +
|
| + /* So this check must pass for the 'return' below to happen.
|
| + */
|
| + if (crc == png_sRGB_checks[i].crc)
|
| +# endif
|
| + {
|
| + if (png_sRGB_checks[i].is_broken != 0)
|
| + {
|
| + /* These profiles are known to have bad data that may cause
|
| + * problems if they are used, therefore attempt to
|
| + * discourage their use, skip the 'have_md5' warning below,
|
| + * which is made irrelevant by this error.
|
| + */
|
| + png_chunk_report(png_ptr, "known incorrect sRGB profile",
|
| + PNG_CHUNK_ERROR);
|
| + }
|
| +
|
| + /* Warn that this being done; this isn't even an error since
|
| + * the profile is perfectly valid, but it would be nice if
|
| + * people used the up-to-date ones.
|
| + */
|
| + else if (png_sRGB_checks[i].have_md5 == 0)
|
| + {
|
| + png_chunk_report(png_ptr,
|
| + "out-of-date sRGB profile with no signature",
|
| + PNG_CHUNK_WARNING);
|
| + }
|
| +
|
| + return 1+png_sRGB_checks[i].is_broken;
|
| + }
|
| + }
|
| +
|
| +# if PNG_sRGB_PROFILE_CHECKS > 0
|
| + /* The signature matched, but the profile had been changed in some
|
| + * way. This probably indicates a data error or uninformed hacking.
|
| + * Fall through to "no match".
|
| + */
|
| + png_chunk_report(png_ptr,
|
| + "Not recognizing known sRGB profile that has been edited",
|
| + PNG_CHUNK_WARNING);
|
| + break;
|
| +# endif
|
| + }
|
| + }
|
| + }
|
| +
|
| + return 0; /* no match */
|
| +}
|
| +#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
|
| +
|
| +void /* PRIVATE */
|
| +png_icc_set_sRGB(png_const_structrp png_ptr,
|
| + png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
|
| +{
|
| + /* Is this profile one of the known ICC sRGB profiles? If it is, just set
|
| + * the sRGB information.
|
| + */
|
| +#if PNG_sRGB_PROFILE_CHECKS >= 0
|
| + if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
|
| +#endif
|
| + (void)png_colorspace_set_sRGB(png_ptr, colorspace,
|
| + (int)/*already checked*/png_get_uint_32(profile+64));
|
| +}
|
| +#endif /* sRGB */
|
| +
|
| +int /* PRIVATE */
|
| +png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
|
| + png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
|
| + int color_type)
|
| +{
|
| + if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
|
| + return 0;
|
| +
|
| + if (png_icc_check_length(png_ptr, colorspace, name, profile_length) != 0 &&
|
| + png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
|
| + color_type) != 0 &&
|
| + png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
|
| + profile) != 0)
|
| + {
|
| +# ifdef PNG_sRGB_SUPPORTED
|
| + /* If no sRGB support, don't try storing sRGB information */
|
| + png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
|
| +# endif
|
| + return 1;
|
| + }
|
| +
|
| + /* Failure case */
|
| + return 0;
|
| +}
|
| +#endif /* iCCP */
|
| +
|
| +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
| +void /* PRIVATE */
|
| +png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
|
| +{
|
| + /* Set the rgb_to_gray coefficients from the colorspace. */
|
| + if (png_ptr->rgb_to_gray_coefficients_set == 0 &&
|
| + (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
|
| + {
|
| + /* png_set_background has not been called, get the coefficients from the Y
|
| + * values of the colorspace colorants.
|
| + */
|
| + png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y;
|
| + png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y;
|
| + png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y;
|
| + png_fixed_point total = r+g+b;
|
| +
|
| + if (total > 0 &&
|
| + r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 &&
|
| + g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 &&
|
| + b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 &&
|
| + r+g+b <= 32769)
|
| + {
|
| + /* We allow 0 coefficients here. r+g+b may be 32769 if two or
|
| + * all of the coefficients were rounded up. Handle this by
|
| + * reducing the *largest* coefficient by 1; this matches the
|
| + * approach used for the default coefficients in pngrtran.c
|
| + */
|
| + int add = 0;
|
| +
|
| + if (r+g+b > 32768)
|
| + add = -1;
|
| + else if (r+g+b < 32768)
|
| + add = 1;
|
| +
|
| + if (add != 0)
|
| + {
|
| + if (g >= r && g >= b)
|
| + g += add;
|
| + else if (r >= g && r >= b)
|
| + r += add;
|
| + else
|
| + b += add;
|
| + }
|
| +
|
| + /* Check for an internal error. */
|
| + if (r+g+b != 32768)
|
| + png_error(png_ptr,
|
| + "internal error handling cHRM coefficients");
|
| +
|
| + else
|
| + {
|
| + png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
|
| + png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
|
| + }
|
| + }
|
| +
|
| + /* This is a png_error at present even though it could be ignored -
|
| + * it should never happen, but it is important that if it does, the
|
| + * bug is fixed.
|
| + */
|
| + else
|
| + png_error(png_ptr, "internal error handling cHRM->XYZ");
|
| + }
|
| +}
|
| +#endif /* READ_RGB_TO_GRAY */
|
| +
|
| +#endif /* COLORSPACE */
|
| +
|
| +#ifdef __GNUC__
|
| +/* This exists solely to work round a warning from GNU C. */
|
| +static int /* PRIVATE */
|
| +png_gt(size_t a, size_t b)
|
| +{
|
| + return a > b;
|
| +}
|
| +#else
|
| +# define png_gt(a,b) ((a) > (b))
|
| +#endif
|
| +
|
| +void /* PRIVATE */
|
| +png_check_IHDR(png_const_structrp png_ptr,
|
| + png_uint_32 width, png_uint_32 height, int bit_depth,
|
| + int color_type, int interlace_type, int compression_type,
|
| + int filter_type)
|
| +{
|
| + int error = 0;
|
| +
|
| + /* Check for width and height valid values */
|
| + if (width == 0)
|
| + {
|
| + png_warning(png_ptr, "Image width is zero in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (width > PNG_UINT_31_MAX)
|
| + {
|
| + png_warning(png_ptr, "Invalid image width in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (png_gt(((width + 7) & (~7)),
|
| + ((PNG_SIZE_MAX
|
| + - 48 /* big_row_buf hack */
|
| + - 1) /* filter byte */
|
| + / 8) /* 8-byte RGBA pixels */
|
| + - 1)) /* extra max_pixel_depth pad */
|
| + {
|
| + /* The size of the row must be within the limits of this architecture.
|
| + * Because the read code can perform arbitrary transformations the
|
| + * maximum size is checked here. Because the code in png_read_start_row
|
| + * adds extra space "for safety's sake" in several places a conservative
|
| + * limit is used here.
|
| + *
|
| + * NOTE: it would be far better to check the size that is actually used,
|
| + * but the effect in the real world is minor and the changes are more
|
| + * extensive, therefore much more dangerous and much more difficult to
|
| + * write in a way that avoids compiler warnings.
|
| + */
|
| + png_warning(png_ptr, "Image width is too large for this architecture");
|
| + error = 1;
|
| + }
|
| +
|
| +#ifdef PNG_SET_USER_LIMITS_SUPPORTED
|
| + if (width > png_ptr->user_width_max)
|
| +#else
|
| + if (width > PNG_USER_WIDTH_MAX)
|
| +#endif
|
| + {
|
| + png_warning(png_ptr, "Image width exceeds user limit in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (height == 0)
|
| + {
|
| + png_warning(png_ptr, "Image height is zero in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (height > PNG_UINT_31_MAX)
|
| + {
|
| + png_warning(png_ptr, "Invalid image height in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| +#ifdef PNG_SET_USER_LIMITS_SUPPORTED
|
| + if (height > png_ptr->user_height_max)
|
| +#else
|
| + if (height > PNG_USER_HEIGHT_MAX)
|
| +#endif
|
| + {
|
| + png_warning(png_ptr, "Image height exceeds user limit in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + /* Check other values */
|
| + if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
|
| + bit_depth != 8 && bit_depth != 16)
|
| + {
|
| + png_warning(png_ptr, "Invalid bit depth in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (color_type < 0 || color_type == 1 ||
|
| + color_type == 5 || color_type > 6)
|
| + {
|
| + png_warning(png_ptr, "Invalid color type in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
|
| + ((color_type == PNG_COLOR_TYPE_RGB ||
|
| + color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
|
| + color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
|
| + {
|
| + png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (interlace_type >= PNG_INTERLACE_LAST)
|
| + {
|
| + png_warning(png_ptr, "Unknown interlace method in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if (compression_type != PNG_COMPRESSION_TYPE_BASE)
|
| + {
|
| + png_warning(png_ptr, "Unknown compression method in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| +#ifdef PNG_MNG_FEATURES_SUPPORTED
|
| + /* Accept filter_method 64 (intrapixel differencing) only if
|
| + * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
|
| + * 2. Libpng did not read a PNG signature (this filter_method is only
|
| + * used in PNG datastreams that are embedded in MNG datastreams) and
|
| + * 3. The application called png_permit_mng_features with a mask that
|
| + * included PNG_FLAG_MNG_FILTER_64 and
|
| + * 4. The filter_method is 64 and
|
| + * 5. The color_type is RGB or RGBA
|
| + */
|
| + if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
|
| + png_ptr->mng_features_permitted != 0)
|
| + png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
|
| +
|
| + if (filter_type != PNG_FILTER_TYPE_BASE)
|
| + {
|
| + if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
|
| + (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
|
| + ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
|
| + (color_type == PNG_COLOR_TYPE_RGB ||
|
| + color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
|
| + {
|
| + png_warning(png_ptr, "Unknown filter method in IHDR");
|
| + error = 1;
|
| + }
|
| +
|
| + if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0)
|
| + {
|
| + png_warning(png_ptr, "Invalid filter method in IHDR");
|
| + error = 1;
|
| + }
|
| + }
|
| +
|
| +#else
|
| + if (filter_type != PNG_FILTER_TYPE_BASE)
|
| + {
|
| + png_warning(png_ptr, "Unknown filter method in IHDR");
|
| + error = 1;
|
| + }
|
| +#endif
|
| +
|
| + if (error == 1)
|
| + png_error(png_ptr, "Invalid IHDR data");
|
| +}
|
| +
|
| +#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
|
| +/* ASCII to fp functions */
|
| +/* Check an ASCII formated floating point value, see the more detailed
|
| + * comments in pngpriv.h
|
| + */
|
| +/* The following is used internally to preserve the sticky flags */
|
| +#define png_fp_add(state, flags) ((state) |= (flags))
|
| +#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
|
| +
|
| +int /* PRIVATE */
|
| +png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
|
| + png_size_tp whereami)
|
| +{
|
| + int state = *statep;
|
| + png_size_t i = *whereami;
|
| +
|
| + while (i < size)
|
| + {
|
| + int type;
|
| + /* First find the type of the next character */
|
| + switch (string[i])
|
| + {
|
| + case 43: type = PNG_FP_SAW_SIGN; break;
|
| + case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
|
| + case 46: type = PNG_FP_SAW_DOT; break;
|
| + case 48: type = PNG_FP_SAW_DIGIT; break;
|
| + case 49: case 50: case 51: case 52:
|
| + case 53: case 54: case 55: case 56:
|
| + case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
|
| + case 69:
|
| + case 101: type = PNG_FP_SAW_E; break;
|
| + default: goto PNG_FP_End;
|
| + }
|
| +
|
| + /* Now deal with this type according to the current
|
| + * state, the type is arranged to not overlap the
|
| + * bits of the PNG_FP_STATE.
|
| + */
|
| + switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
|
| + {
|
| + case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
|
| + if ((state & PNG_FP_SAW_ANY) != 0)
|
| + goto PNG_FP_End; /* not a part of the number */
|
| +
|
| + png_fp_add(state, type);
|
| + break;
|
| +
|
| + case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
|
| + /* Ok as trailer, ok as lead of fraction. */
|
| + if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */
|
| + goto PNG_FP_End;
|
| +
|
| + else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */
|
| + png_fp_add(state, type);
|
| +
|
| + else
|
| + png_fp_set(state, PNG_FP_FRACTION | type);
|
| +
|
| + break;
|
| +
|
| + case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
|
| + if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */
|
| + png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
|
| +
|
| + png_fp_add(state, type | PNG_FP_WAS_VALID);
|
| +
|
| + break;
|
| +
|
| + case PNG_FP_INTEGER + PNG_FP_SAW_E:
|
| + if ((state & PNG_FP_SAW_DIGIT) == 0)
|
| + goto PNG_FP_End;
|
| +
|
| + png_fp_set(state, PNG_FP_EXPONENT);
|
| +
|
| + break;
|
| +
|
| + /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
|
| + goto PNG_FP_End; ** no sign in fraction */
|
| +
|
| + /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
|
| + goto PNG_FP_End; ** Because SAW_DOT is always set */
|
| +
|
| + case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
|
| + png_fp_add(state, type | PNG_FP_WAS_VALID);
|
| + break;
|
| +
|
| + case PNG_FP_FRACTION + PNG_FP_SAW_E:
|
| + /* This is correct because the trailing '.' on an
|
| + * integer is handled above - so we can only get here
|
| + * with the sequence ".E" (with no preceding digits).
|
| + */
|
| + if ((state & PNG_FP_SAW_DIGIT) == 0)
|
| + goto PNG_FP_End;
|
| +
|
| + png_fp_set(state, PNG_FP_EXPONENT);
|
| +
|
| + break;
|
| +
|
| + case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
|
| + if ((state & PNG_FP_SAW_ANY) != 0)
|
| + goto PNG_FP_End; /* not a part of the number */
|
| +
|
| + png_fp_add(state, PNG_FP_SAW_SIGN);
|
| +
|
| + break;
|
| +
|
| + /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
|
| + goto PNG_FP_End; */
|
| +
|
| + case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
|
| + png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
|
| +
|
| + break;
|
| +
|
| + /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
|
| + goto PNG_FP_End; */
|
| +
|
| + default: goto PNG_FP_End; /* I.e. break 2 */
|
| + }
|
| +
|
| + /* The character seems ok, continue. */
|
| + ++i;
|
| + }
|
| +
|
| +PNG_FP_End:
|
| + /* Here at the end, update the state and return the correct
|
| + * return code.
|
| + */
|
| + *statep = state;
|
| + *whereami = i;
|
| +
|
| + return (state & PNG_FP_SAW_DIGIT) != 0;
|
| +}
|
| +
|
| +
|
| +/* The same but for a complete string. */
|
| +int
|
| +png_check_fp_string(png_const_charp string, png_size_t size)
|
| +{
|
| + int state=0;
|
| + png_size_t char_index=0;
|
| +
|
| + if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
|
| + (char_index == size || string[char_index] == 0))
|
| + return state /* must be non-zero - see above */;
|
| +
|
| + return 0; /* i.e. fail */
|
| +}
|
| +#endif /* pCAL || sCAL */
|
| +
|
| +#ifdef PNG_sCAL_SUPPORTED
|
| +# ifdef PNG_FLOATING_POINT_SUPPORTED
|
| +/* Utility used below - a simple accurate power of ten from an integral
|
| + * exponent.
|
| + */
|
| +static double
|
| +png_pow10(int power)
|
| +{
|
| + int recip = 0;
|
| + double d = 1;
|
| +
|
| + /* Handle negative exponent with a reciprocal at the end because
|
| + * 10 is exact whereas .1 is inexact in base 2
|
| + */
|
| + if (power < 0)
|
| + {
|
| + if (power < DBL_MIN_10_EXP) return 0;
|
| + recip = 1, power = -power;
|
| + }
|
| +
|
| + if (power > 0)
|
| + {
|
| + /* Decompose power bitwise. */
|
| + double mult = 10;
|
| + do
|
| + {
|
| + if (power & 1) d *= mult;
|
| + mult *= mult;
|
| + power >>= 1;
|
| + }
|
| + while (power > 0);
|
| +
|
| + if (recip != 0) d = 1/d;
|
| + }
|
| + /* else power is 0 and d is 1 */
|
| +
|
| + return d;
|
| +}
|
| +
|
| +/* Function to format a floating point value in ASCII with a given
|
| + * precision.
|
| + */
|
| +void /* PRIVATE */
|
| +png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
|
| + double fp, unsigned int precision)
|
| +{
|
| + /* We use standard functions from math.h, but not printf because
|
| + * that would require stdio. The caller must supply a buffer of
|
| + * sufficient size or we will png_error. The tests on size and
|
| + * the space in ascii[] consumed are indicated below.
|
| + */
|
| + if (precision < 1)
|
| + precision = DBL_DIG;
|
| +
|
| + /* Enforce the limit of the implementation precision too. */
|
| + if (precision > DBL_DIG+1)
|
| + precision = DBL_DIG+1;
|
| +
|
| + /* Basic sanity checks */
|
| + if (size >= precision+5) /* See the requirements below. */
|
| + {
|
| + if (fp < 0)
|
| + {
|
| + fp = -fp;
|
| + *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */
|
| + --size;
|
| + }
|
| +
|
| + if (fp >= DBL_MIN && fp <= DBL_MAX)
|
| + {
|
| + int exp_b10; /* A base 10 exponent */
|
| + double base; /* 10^exp_b10 */
|
| +
|
| + /* First extract a base 10 exponent of the number,
|
| + * the calculation below rounds down when converting
|
| + * from base 2 to base 10 (multiply by log10(2) -
|
| + * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
|
| + * be increased. Note that the arithmetic shift
|
| + * performs a floor() unlike C arithmetic - using a
|
| + * C multiply would break the following for negative
|
| + * exponents.
|
| + */
|
| + (void)frexp(fp, &exp_b10); /* exponent to base 2 */
|
| +
|
| + exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
|
| +
|
| + /* Avoid underflow here. */
|
| + base = png_pow10(exp_b10); /* May underflow */
|
| +
|
| + while (base < DBL_MIN || base < fp)
|
| + {
|
| + /* And this may overflow. */
|
| + double test = png_pow10(exp_b10+1);
|
| +
|
| + if (test <= DBL_MAX)
|
| + ++exp_b10, base = test;
|
| +
|
| + else
|
| + break;
|
| + }
|
| +
|
| + /* Normalize fp and correct exp_b10, after this fp is in the
|
| + * range [.1,1) and exp_b10 is both the exponent and the digit
|
| + * *before* which the decimal point should be inserted
|
| + * (starting with 0 for the first digit). Note that this
|
| + * works even if 10^exp_b10 is out of range because of the
|
| + * test on DBL_MAX above.
|
| + */
|
| + fp /= base;
|
| + while (fp >= 1) fp /= 10, ++exp_b10;
|
| +
|
| + /* Because of the code above fp may, at this point, be
|
| + * less than .1, this is ok because the code below can
|
| + * handle the leading zeros this generates, so no attempt
|
| + * is made to correct that here.
|
| + */
|
| +
|
| + {
|
| + unsigned int czero, clead, cdigits;
|
| + char exponent[10];
|
| +
|
| + /* Allow up to two leading zeros - this will not lengthen
|
| + * the number compared to using E-n.
|
| + */
|
| + if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
|
| + {
|
| + czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */
|
| + exp_b10 = 0; /* Dot added below before first output. */
|
| + }
|
| + else
|
| + czero = 0; /* No zeros to add */
|
| +
|
| + /* Generate the digit list, stripping trailing zeros and
|
| + * inserting a '.' before a digit if the exponent is 0.
|
| + */
|
| + clead = czero; /* Count of leading zeros */
|
| + cdigits = 0; /* Count of digits in list. */
|
| +
|
| + do
|
| + {
|
| + double d;
|
| +
|
| + fp *= 10;
|
| + /* Use modf here, not floor and subtract, so that
|
| + * the separation is done in one step. At the end
|
| + * of the loop don't break the number into parts so
|
| + * that the final digit is rounded.
|
| + */
|
| + if (cdigits+czero+1 < precision+clead)
|
| + fp = modf(fp, &d);
|
| +
|
| + else
|
| + {
|
| + d = floor(fp + .5);
|
| +
|
| + if (d > 9)
|
| + {
|
| + /* Rounding up to 10, handle that here. */
|
| + if (czero > 0)
|
| + {
|
| + --czero, d = 1;
|
| + if (cdigits == 0) --clead;
|
| + }
|
| + else
|
| + {
|
| + while (cdigits > 0 && d > 9)
|
| + {
|
| + int ch = *--ascii;
|
| +
|
| + if (exp_b10 != (-1))
|
| + ++exp_b10;
|
| +
|
| + else if (ch == 46)
|
| + {
|
| + ch = *--ascii, ++size;
|
| + /* Advance exp_b10 to '1', so that the
|
| + * decimal point happens after the
|
| + * previous digit.
|
| + */
|
| + exp_b10 = 1;
|
| + }
|
| +
|
| + --cdigits;
|
| + d = ch - 47; /* I.e. 1+(ch-48) */
|
| + }
|
| +
|
| + /* Did we reach the beginning? If so adjust the
|
| + * exponent but take into account the leading
|
| + * decimal point.
|
| + */
|
| + if (d > 9) /* cdigits == 0 */
|
| + {
|
| + if (exp_b10 == (-1))
|
| + {
|
| + /* Leading decimal point (plus zeros?), if
|
| + * we lose the decimal point here it must
|
| + * be reentered below.
|
| + */
|
| + int ch = *--ascii;
|
| +
|
| + if (ch == 46)
|
| + ++size, exp_b10 = 1;
|
| +
|
| + /* Else lost a leading zero, so 'exp_b10' is
|
| + * still ok at (-1)
|
| + */
|
| + }
|
| + else
|
| + ++exp_b10;
|
| +
|
| + /* In all cases we output a '1' */
|
| + d = 1;
|
| + }
|
| + }
|
| + }
|
| + fp = 0; /* Guarantees termination below. */
|
| + }
|
| +
|
| + if (d == 0)
|
| + {
|
| + ++czero;
|
| + if (cdigits == 0) ++clead;
|
| + }
|
| + else
|
| + {
|
| + /* Included embedded zeros in the digit count. */
|
| + cdigits += czero - clead;
|
| + clead = 0;
|
| +
|
| + while (czero > 0)
|
| + {
|
| + /* exp_b10 == (-1) means we just output the decimal
|
| + * place - after the DP don't adjust 'exp_b10' any
|
| + * more!
|
| + */
|
| + if (exp_b10 != (-1))
|
| + {
|
| + if (exp_b10 == 0) *ascii++ = 46, --size;
|
| + /* PLUS 1: TOTAL 4 */
|
| + --exp_b10;
|
| + }
|
| + *ascii++ = 48, --czero;
|
| + }
|
| +
|
| + if (exp_b10 != (-1))
|
| + {
|
| + if (exp_b10 == 0)
|
| + *ascii++ = 46, --size; /* counted above */
|
| +
|
| + --exp_b10;
|
| + }
|
| + *ascii++ = (char)(48 + (int)d), ++cdigits;
|
| + }
|
| + }
|
| + while (cdigits+czero < precision+clead && fp > DBL_MIN);
|
| +
|
| + /* The total output count (max) is now 4+precision */
|
| +
|
| + /* Check for an exponent, if we don't need one we are
|
| + * done and just need to terminate the string. At
|
| + * this point exp_b10==(-1) is effectively if flag - it got
|
| + * to '-1' because of the decrement after outputting
|
| + * the decimal point above (the exponent required is
|
| + * *not* -1!)
|
| + */
|
| + if (exp_b10 >= (-1) && exp_b10 <= 2)
|
| + {
|
| + /* The following only happens if we didn't output the
|
| + * leading zeros above for negative exponent, so this
|
| + * doesn't add to the digit requirement. Note that the
|
| + * two zeros here can only be output if the two leading
|
| + * zeros were *not* output, so this doesn't increase
|
| + * the output count.
|
| + */
|
| + while (--exp_b10 >= 0) *ascii++ = 48;
|
| +
|
| + *ascii = 0;
|
| +
|
| + /* Total buffer requirement (including the '\0') is
|
| + * 5+precision - see check at the start.
|
| + */
|
| + return;
|
| + }
|
| +
|
| + /* Here if an exponent is required, adjust size for
|
| + * the digits we output but did not count. The total
|
| + * digit output here so far is at most 1+precision - no
|
| + * decimal point and no leading or trailing zeros have
|
| + * been output.
|
| + */
|
| + size -= cdigits;
|
| +
|
| + *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */
|
| +
|
| + /* The following use of an unsigned temporary avoids ambiguities in
|
| + * the signed arithmetic on exp_b10 and permits GCC at least to do
|
| + * better optimization.
|
| + */
|
| + {
|
| + unsigned int uexp_b10;
|
| +
|
| + if (exp_b10 < 0)
|
| + {
|
| + *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
|
| + uexp_b10 = -exp_b10;
|
| + }
|
| +
|
| + else
|
| + uexp_b10 = exp_b10;
|
| +
|
| + cdigits = 0;
|
| +
|
| + while (uexp_b10 > 0)
|
| + {
|
| + exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
|
| + uexp_b10 /= 10;
|
| + }
|
| + }
|
| +
|
| + /* Need another size check here for the exponent digits, so
|
| + * this need not be considered above.
|
| + */
|
| + if (size > cdigits)
|
| + {
|
| + while (cdigits > 0) *ascii++ = exponent[--cdigits];
|
| +
|
| + *ascii = 0;
|
| +
|
| + return;
|
| + }
|
| + }
|
| + }
|
| + else if (!(fp >= DBL_MIN))
|
| + {
|
| + *ascii++ = 48; /* '0' */
|
| + *ascii = 0;
|
| + return;
|
| + }
|
| + else
|
| + {
|
| + *ascii++ = 105; /* 'i' */
|
| + *ascii++ = 110; /* 'n' */
|
| + *ascii++ = 102; /* 'f' */
|
| + *ascii = 0;
|
| + return;
|
| + }
|
| + }
|
| +
|
| + /* Here on buffer too small. */
|
| + png_error(png_ptr, "ASCII conversion buffer too small");
|
| +}
|
| +
|
| +# endif /* FLOATING_POINT */
|
| +
|
| +# ifdef PNG_FIXED_POINT_SUPPORTED
|
| +/* Function to format a fixed point value in ASCII.
|
| + */
|
| +void /* PRIVATE */
|
| +png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
|
| + png_size_t size, png_fixed_point fp)
|
| +{
|
| + /* Require space for 10 decimal digits, a decimal point, a minus sign and a
|
| + * trailing \0, 13 characters:
|
| + */
|
| + if (size > 12)
|
| + {
|
| + png_uint_32 num;
|
| +
|
| + /* Avoid overflow here on the minimum integer. */
|
| + if (fp < 0)
|
| + *ascii++ = 45, num = -fp;
|
| + else
|
| + num = fp;
|
| +
|
| + if (num <= 0x80000000) /* else overflowed */
|
| + {
|
| + unsigned int ndigits = 0, first = 16 /* flag value */;
|
| + char digits[10];
|
| +
|
| + while (num)
|
| + {
|
| + /* Split the low digit off num: */
|
| + unsigned int tmp = num/10;
|
| + num -= tmp*10;
|
| + digits[ndigits++] = (char)(48 + num);
|
| + /* Record the first non-zero digit, note that this is a number
|
| + * starting at 1, it's not actually the array index.
|
| + */
|
| + if (first == 16 && num > 0)
|
| + first = ndigits;
|
| + num = tmp;
|
| + }
|
| +
|
| + if (ndigits > 0)
|
| + {
|
| + while (ndigits > 5) *ascii++ = digits[--ndigits];
|
| + /* The remaining digits are fractional digits, ndigits is '5' or
|
| + * smaller at this point. It is certainly not zero. Check for a
|
| + * non-zero fractional digit:
|
| + */
|
| + if (first <= 5)
|
| + {
|
| + unsigned int i;
|
| + *ascii++ = 46; /* decimal point */
|
| + /* ndigits may be <5 for small numbers, output leading zeros
|
| + * then ndigits digits to first:
|
| + */
|
| + i = 5;
|
| + while (ndigits < i) *ascii++ = 48, --i;
|
| + while (ndigits >= first) *ascii++ = digits[--ndigits];
|
| + /* Don't output the trailing zeros! */
|
| + }
|
| + }
|
| + else
|
| + *ascii++ = 48;
|
| +
|
| + /* And null terminate the string: */
|
| + *ascii = 0;
|
| + return;
|
| + }
|
| + }
|
| +
|
| + /* Here on buffer too small. */
|
| + png_error(png_ptr, "ASCII conversion buffer too small");
|
| +}
|
| +# endif /* FIXED_POINT */
|
| +#endif /* SCAL */
|
| +
|
| +#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
|
| + !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
|
| + (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
|
| + defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
|
| + (defined(PNG_sCAL_SUPPORTED) && \
|
| + defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
|
| +png_fixed_point
|
| +png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
|
| +{
|
| + double r = floor(100000 * fp + .5);
|
| +
|
| + if (r > 2147483647. || r < -2147483648.)
|
| + png_fixed_error(png_ptr, text);
|
| +
|
| +# ifndef PNG_ERROR_TEXT_SUPPORTED
|
| + PNG_UNUSED(text)
|
| +# endif
|
| +
|
| + return (png_fixed_point)r;
|
| +}
|
| +#endif
|
| +
|
| +#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\
|
| + defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
|
| +/* muldiv functions */
|
| +/* This API takes signed arguments and rounds the result to the nearest
|
| + * integer (or, for a fixed point number - the standard argument - to
|
| + * the nearest .00001). Overflow and divide by zero are signalled in
|
| + * the result, a boolean - true on success, false on overflow.
|
| + */
|
| +int
|
| +png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
|
| + png_int_32 divisor)
|
| +{
|
| + /* Return a * times / divisor, rounded. */
|
| + if (divisor != 0)
|
| + {
|
| + if (a == 0 || times == 0)
|
| + {
|
| + *res = 0;
|
| + return 1;
|
| + }
|
| + else
|
| + {
|
| +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + double r = a;
|
| + r *= times;
|
| + r /= divisor;
|
| + r = floor(r+.5);
|
| +
|
| + /* A png_fixed_point is a 32-bit integer. */
|
| + if (r <= 2147483647. && r >= -2147483648.)
|
| + {
|
| + *res = (png_fixed_point)r;
|
| + return 1;
|
| + }
|
| +#else
|
| + int negative = 0;
|
| + png_uint_32 A, T, D;
|
| + png_uint_32 s16, s32, s00;
|
| +
|
| + if (a < 0)
|
| + negative = 1, A = -a;
|
| + else
|
| + A = a;
|
| +
|
| + if (times < 0)
|
| + negative = !negative, T = -times;
|
| + else
|
| + T = times;
|
| +
|
| + if (divisor < 0)
|
| + negative = !negative, D = -divisor;
|
| + else
|
| + D = divisor;
|
| +
|
| + /* Following can't overflow because the arguments only
|
| + * have 31 bits each, however the result may be 32 bits.
|
| + */
|
| + s16 = (A >> 16) * (T & 0xffff) +
|
| + (A & 0xffff) * (T >> 16);
|
| + /* Can't overflow because the a*times bit is only 30
|
| + * bits at most.
|
| + */
|
| + s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
|
| + s00 = (A & 0xffff) * (T & 0xffff);
|
| +
|
| + s16 = (s16 & 0xffff) << 16;
|
| + s00 += s16;
|
| +
|
| + if (s00 < s16)
|
| + ++s32; /* carry */
|
| +
|
| + if (s32 < D) /* else overflow */
|
| + {
|
| + /* s32.s00 is now the 64-bit product, do a standard
|
| + * division, we know that s32 < D, so the maximum
|
| + * required shift is 31.
|
| + */
|
| + int bitshift = 32;
|
| + png_fixed_point result = 0; /* NOTE: signed */
|
| +
|
| + while (--bitshift >= 0)
|
| + {
|
| + png_uint_32 d32, d00;
|
| +
|
| + if (bitshift > 0)
|
| + d32 = D >> (32-bitshift), d00 = D << bitshift;
|
| +
|
| + else
|
| + d32 = 0, d00 = D;
|
| +
|
| + if (s32 > d32)
|
| + {
|
| + if (s00 < d00) --s32; /* carry */
|
| + s32 -= d32, s00 -= d00, result += 1<<bitshift;
|
| + }
|
| +
|
| + else
|
| + if (s32 == d32 && s00 >= d00)
|
| + s32 = 0, s00 -= d00, result += 1<<bitshift;
|
| + }
|
| +
|
| + /* Handle the rounding. */
|
| + if (s00 >= (D >> 1))
|
| + ++result;
|
| +
|
| + if (negative != 0)
|
| + result = -result;
|
| +
|
| + /* Check for overflow. */
|
| + if ((negative != 0 && result <= 0) ||
|
| + (negative == 0 && result >= 0))
|
| + {
|
| + *res = result;
|
| + return 1;
|
| + }
|
| + }
|
| +#endif
|
| + }
|
| + }
|
| +
|
| + return 0;
|
| +}
|
| +#endif /* READ_GAMMA || INCH_CONVERSIONS */
|
| +
|
| +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
|
| +/* The following is for when the caller doesn't much care about the
|
| + * result.
|
| + */
|
| +png_fixed_point
|
| +png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
|
| + png_int_32 divisor)
|
| +{
|
| + png_fixed_point result;
|
| +
|
| + if (png_muldiv(&result, a, times, divisor) != 0)
|
| + return result;
|
| +
|
| + png_warning(png_ptr, "fixed point overflow ignored");
|
| + return 0;
|
| +}
|
| +#endif
|
| +
|
| +#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */
|
| +/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
|
| +png_fixed_point
|
| +png_reciprocal(png_fixed_point a)
|
| +{
|
| +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + double r = floor(1E10/a+.5);
|
| +
|
| + if (r <= 2147483647. && r >= -2147483648.)
|
| + return (png_fixed_point)r;
|
| +#else
|
| + png_fixed_point res;
|
| +
|
| + if (png_muldiv(&res, 100000, 100000, a) != 0)
|
| + return res;
|
| +#endif
|
| +
|
| + return 0; /* error/overflow */
|
| +}
|
| +
|
| +/* This is the shared test on whether a gamma value is 'significant' - whether
|
| + * it is worth doing gamma correction.
|
| + */
|
| +int /* PRIVATE */
|
| +png_gamma_significant(png_fixed_point gamma_val)
|
| +{
|
| + return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
|
| + gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
|
| +}
|
| +#endif
|
| +
|
| +#ifdef PNG_READ_GAMMA_SUPPORTED
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| +/* A local convenience routine. */
|
| +static png_fixed_point
|
| +png_product2(png_fixed_point a, png_fixed_point b)
|
| +{
|
| + /* The required result is 1/a * 1/b; the following preserves accuracy. */
|
| +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + double r = a * 1E-5;
|
| + r *= b;
|
| + r = floor(r+.5);
|
| +
|
| + if (r <= 2147483647. && r >= -2147483648.)
|
| + return (png_fixed_point)r;
|
| +#else
|
| + png_fixed_point res;
|
| +
|
| + if (png_muldiv(&res, a, b, 100000) != 0)
|
| + return res;
|
| +#endif
|
| +
|
| + return 0; /* overflow */
|
| +}
|
| +#endif /* 16BIT */
|
| +
|
| +/* The inverse of the above. */
|
| +png_fixed_point
|
| +png_reciprocal2(png_fixed_point a, png_fixed_point b)
|
| +{
|
| + /* The required result is 1/a * 1/b; the following preserves accuracy. */
|
| +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + if (a != 0 && b != 0)
|
| + {
|
| + double r = 1E15/a;
|
| + r /= b;
|
| + r = floor(r+.5);
|
| +
|
| + if (r <= 2147483647. && r >= -2147483648.)
|
| + return (png_fixed_point)r;
|
| + }
|
| +#else
|
| + /* This may overflow because the range of png_fixed_point isn't symmetric,
|
| + * but this API is only used for the product of file and screen gamma so it
|
| + * doesn't matter that the smallest number it can produce is 1/21474, not
|
| + * 1/100000
|
| + */
|
| + png_fixed_point res = png_product2(a, b);
|
| +
|
| + if (res != 0)
|
| + return png_reciprocal(res);
|
| +#endif
|
| +
|
| + return 0; /* overflow */
|
| +}
|
| +#endif /* READ_GAMMA */
|
| +
|
| +#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
|
| +#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| +/* Fixed point gamma.
|
| + *
|
| + * The code to calculate the tables used below can be found in the shell script
|
| + * contrib/tools/intgamma.sh
|
| + *
|
| + * To calculate gamma this code implements fast log() and exp() calls using only
|
| + * fixed point arithmetic. This code has sufficient precision for either 8-bit
|
| + * or 16-bit sample values.
|
| + *
|
| + * The tables used here were calculated using simple 'bc' programs, but C double
|
| + * precision floating point arithmetic would work fine.
|
| + *
|
| + * 8-bit log table
|
| + * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
|
| + * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
|
| + * mantissa. The numbers are 32-bit fractions.
|
| + */
|
| +static const png_uint_32
|
| +png_8bit_l2[128] =
|
| +{
|
| + 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
|
| + 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
|
| + 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
|
| + 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
|
| + 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
|
| + 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
|
| + 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
|
| + 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
|
| + 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
|
| + 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
|
| + 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
|
| + 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
|
| + 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
|
| + 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
|
| + 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
|
| + 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
|
| + 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
|
| + 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
|
| + 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
|
| + 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
|
| + 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
|
| + 24347096U, 0U
|
| +
|
| +#if 0
|
| + /* The following are the values for 16-bit tables - these work fine for the
|
| + * 8-bit conversions but produce very slightly larger errors in the 16-bit
|
| + * log (about 1.2 as opposed to 0.7 absolute error in the final value). To
|
| + * use these all the shifts below must be adjusted appropriately.
|
| + */
|
| + 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
|
| + 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
|
| + 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
|
| + 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
|
| + 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
|
| + 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
|
| + 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
|
| + 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
|
| + 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
|
| + 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
|
| + 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
|
| + 1119, 744, 372
|
| +#endif
|
| +};
|
| +
|
| +static png_int_32
|
| +png_log8bit(unsigned int x)
|
| +{
|
| + unsigned int lg2 = 0;
|
| + /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
|
| + * because the log is actually negate that means adding 1. The final
|
| + * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
|
| + * input), return -1 for the overflow (log 0) case, - so the result is
|
| + * always at most 19 bits.
|
| + */
|
| + if ((x &= 0xff) == 0)
|
| + return -1;
|
| +
|
| + if ((x & 0xf0) == 0)
|
| + lg2 = 4, x <<= 4;
|
| +
|
| + if ((x & 0xc0) == 0)
|
| + lg2 += 2, x <<= 2;
|
| +
|
| + if ((x & 0x80) == 0)
|
| + lg2 += 1, x <<= 1;
|
| +
|
| + /* result is at most 19 bits, so this cast is safe: */
|
| + return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
|
| +}
|
| +
|
| +/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
|
| + * for 16-bit images we use the most significant 8 bits of the 16-bit value to
|
| + * get an approximation then multiply the approximation by a correction factor
|
| + * determined by the remaining up to 8 bits. This requires an additional step
|
| + * in the 16-bit case.
|
| + *
|
| + * We want log2(value/65535), we have log2(v'/255), where:
|
| + *
|
| + * value = v' * 256 + v''
|
| + * = v' * f
|
| + *
|
| + * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
|
| + * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
|
| + * than 258. The final factor also needs to correct for the fact that our 8-bit
|
| + * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
|
| + *
|
| + * This gives a final formula using a calculated value 'x' which is value/v' and
|
| + * scaling by 65536 to match the above table:
|
| + *
|
| + * log2(x/257) * 65536
|
| + *
|
| + * Since these numbers are so close to '1' we can use simple linear
|
| + * interpolation between the two end values 256/257 (result -368.61) and 258/257
|
| + * (result 367.179). The values used below are scaled by a further 64 to give
|
| + * 16-bit precision in the interpolation:
|
| + *
|
| + * Start (256): -23591
|
| + * Zero (257): 0
|
| + * End (258): 23499
|
| + */
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| +static png_int_32
|
| +png_log16bit(png_uint_32 x)
|
| +{
|
| + unsigned int lg2 = 0;
|
| +
|
| + /* As above, but now the input has 16 bits. */
|
| + if ((x &= 0xffff) == 0)
|
| + return -1;
|
| +
|
| + if ((x & 0xff00) == 0)
|
| + lg2 = 8, x <<= 8;
|
| +
|
| + if ((x & 0xf000) == 0)
|
| + lg2 += 4, x <<= 4;
|
| +
|
| + if ((x & 0xc000) == 0)
|
| + lg2 += 2, x <<= 2;
|
| +
|
| + if ((x & 0x8000) == 0)
|
| + lg2 += 1, x <<= 1;
|
| +
|
| + /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
|
| + * value.
|
| + */
|
| + lg2 <<= 28;
|
| + lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
|
| +
|
| + /* Now we need to interpolate the factor, this requires a division by the top
|
| + * 8 bits. Do this with maximum precision.
|
| + */
|
| + x = ((x << 16) + (x >> 9)) / (x >> 8);
|
| +
|
| + /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
|
| + * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
|
| + * 16 bits to interpolate to get the low bits of the result. Round the
|
| + * answer. Note that the end point values are scaled by 64 to retain overall
|
| + * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
|
| + * the overall scaling by 6-12. Round at every step.
|
| + */
|
| + x -= 1U << 24;
|
| +
|
| + if (x <= 65536U) /* <= '257' */
|
| + lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
|
| +
|
| + else
|
| + lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
|
| +
|
| + /* Safe, because the result can't have more than 20 bits: */
|
| + return (png_int_32)((lg2 + 2048) >> 12);
|
| +}
|
| +#endif /* 16BIT */
|
| +
|
| +/* The 'exp()' case must invert the above, taking a 20-bit fixed point
|
| + * logarithmic value and returning a 16 or 8-bit number as appropriate. In
|
| + * each case only the low 16 bits are relevant - the fraction - since the
|
| + * integer bits (the top 4) simply determine a shift.
|
| + *
|
| + * The worst case is the 16-bit distinction between 65535 and 65534. This
|
| + * requires perhaps spurious accuracy in the decoding of the logarithm to
|
| + * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
|
| + * of getting this accuracy in practice.
|
| + *
|
| + * To deal with this the following exp() function works out the exponent of the
|
| + * frational part of the logarithm by using an accurate 32-bit value from the
|
| + * top four fractional bits then multiplying in the remaining bits.
|
| + */
|
| +static const png_uint_32
|
| +png_32bit_exp[16] =
|
| +{
|
| + /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
|
| + 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
|
| + 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
|
| + 2553802834U, 2445529972U, 2341847524U, 2242560872U
|
| +};
|
| +
|
| +/* Adjustment table; provided to explain the numbers in the code below. */
|
| +#if 0
|
| +for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
|
| + 11 44937.64284865548751208448
|
| + 10 45180.98734845585101160448
|
| + 9 45303.31936980687359311872
|
| + 8 45364.65110595323018870784
|
| + 7 45395.35850361789624614912
|
| + 6 45410.72259715102037508096
|
| + 5 45418.40724413220722311168
|
| + 4 45422.25021786898173001728
|
| + 3 45424.17186732298419044352
|
| + 2 45425.13273269940811464704
|
| + 1 45425.61317555035558641664
|
| + 0 45425.85339951654943850496
|
| +#endif
|
| +
|
| +static png_uint_32
|
| +png_exp(png_fixed_point x)
|
| +{
|
| + if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
|
| + {
|
| + /* Obtain a 4-bit approximation */
|
| + png_uint_32 e = png_32bit_exp[(x >> 12) & 0x0f];
|
| +
|
| + /* Incorporate the low 12 bits - these decrease the returned value by
|
| + * multiplying by a number less than 1 if the bit is set. The multiplier
|
| + * is determined by the above table and the shift. Notice that the values
|
| + * converge on 45426 and this is used to allow linear interpolation of the
|
| + * low bits.
|
| + */
|
| + if (x & 0x800)
|
| + e -= (((e >> 16) * 44938U) + 16U) >> 5;
|
| +
|
| + if (x & 0x400)
|
| + e -= (((e >> 16) * 45181U) + 32U) >> 6;
|
| +
|
| + if (x & 0x200)
|
| + e -= (((e >> 16) * 45303U) + 64U) >> 7;
|
| +
|
| + if (x & 0x100)
|
| + e -= (((e >> 16) * 45365U) + 128U) >> 8;
|
| +
|
| + if (x & 0x080)
|
| + e -= (((e >> 16) * 45395U) + 256U) >> 9;
|
| +
|
| + if (x & 0x040)
|
| + e -= (((e >> 16) * 45410U) + 512U) >> 10;
|
| +
|
| + /* And handle the low 6 bits in a single block. */
|
| + e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
|
| +
|
| + /* Handle the upper bits of x. */
|
| + e >>= x >> 16;
|
| + return e;
|
| + }
|
| +
|
| + /* Check for overflow */
|
| + if (x <= 0)
|
| + return png_32bit_exp[0];
|
| +
|
| + /* Else underflow */
|
| + return 0;
|
| +}
|
| +
|
| +static png_byte
|
| +png_exp8bit(png_fixed_point lg2)
|
| +{
|
| + /* Get a 32-bit value: */
|
| + png_uint_32 x = png_exp(lg2);
|
| +
|
| + /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the
|
| + * second, rounding, step can't overflow because of the first, subtraction,
|
| + * step.
|
| + */
|
| + x -= x >> 8;
|
| + return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
|
| +}
|
| +
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| +static png_uint_16
|
| +png_exp16bit(png_fixed_point lg2)
|
| +{
|
| + /* Get a 32-bit value: */
|
| + png_uint_32 x = png_exp(lg2);
|
| +
|
| + /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
|
| + x -= x >> 16;
|
| + return (png_uint_16)((x + 32767U) >> 16);
|
| +}
|
| +#endif /* 16BIT */
|
| +#endif /* FLOATING_ARITHMETIC */
|
| +
|
| +png_byte
|
| +png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
|
| +{
|
| + if (value > 0 && value < 255)
|
| + {
|
| +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + /* 'value' is unsigned, ANSI-C90 requires the compiler to correctly
|
| + * convert this to a floating point value. This includes values that
|
| + * would overflow if 'value' were to be converted to 'int'.
|
| + *
|
| + * Apparently GCC, however, does an intermediate conversion to (int)
|
| + * on some (ARM) but not all (x86) platforms, possibly because of
|
| + * hardware FP limitations. (E.g. if the hardware conversion always
|
| + * assumes the integer register contains a signed value.) This results
|
| + * in ANSI-C undefined behavior for large values.
|
| + *
|
| + * Other implementations on the same machine might actually be ANSI-C90
|
| + * conformant and therefore compile spurious extra code for the large
|
| + * values.
|
| + *
|
| + * We can be reasonably sure that an unsigned to float conversion
|
| + * won't be faster than an int to float one. Therefore this code
|
| + * assumes responsibility for the undefined behavior, which it knows
|
| + * can't happen because of the check above.
|
| + *
|
| + * Note the argument to this routine is an (unsigned int) because, on
|
| + * 16-bit platforms, it is assigned a value which might be out of
|
| + * range for an (int); that would result in undefined behavior in the
|
| + * caller if the *argument* ('value') were to be declared (int).
|
| + */
|
| + double r = floor(255*pow((int)/*SAFE*/value/255.,gamma_val*.00001)+.5);
|
| + return (png_byte)r;
|
| +# else
|
| + png_int_32 lg2 = png_log8bit(value);
|
| + png_fixed_point res;
|
| +
|
| + if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
|
| + return png_exp8bit(res);
|
| +
|
| + /* Overflow. */
|
| + value = 0;
|
| +# endif
|
| + }
|
| +
|
| + return (png_byte)(value & 0xff);
|
| +}
|
| +
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| +png_uint_16
|
| +png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
|
| +{
|
| + if (value > 0 && value < 65535)
|
| + {
|
| +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + /* The same (unsigned int)->(double) constraints apply here as above,
|
| + * however in this case the (unsigned int) to (int) conversion can
|
| + * overflow on an ANSI-C90 compliant system so the cast needs to ensure
|
| + * that this is not possible.
|
| + */
|
| + double r = floor(65535*pow((png_int_32)value/65535.,
|
| + gamma_val*.00001)+.5);
|
| + return (png_uint_16)r;
|
| +# else
|
| + png_int_32 lg2 = png_log16bit(value);
|
| + png_fixed_point res;
|
| +
|
| + if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
|
| + return png_exp16bit(res);
|
| +
|
| + /* Overflow. */
|
| + value = 0;
|
| +# endif
|
| + }
|
| +
|
| + return (png_uint_16)value;
|
| +}
|
| +#endif /* 16BIT */
|
| +
|
| +/* This does the right thing based on the bit_depth field of the
|
| + * png_struct, interpreting values as 8-bit or 16-bit. While the result
|
| + * is nominally a 16-bit value if bit depth is 8 then the result is
|
| + * 8-bit (as are the arguments.)
|
| + */
|
| +png_uint_16 /* PRIVATE */
|
| +png_gamma_correct(png_structrp png_ptr, unsigned int value,
|
| + png_fixed_point gamma_val)
|
| +{
|
| + if (png_ptr->bit_depth == 8)
|
| + return png_gamma_8bit_correct(value, gamma_val);
|
| +
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| + else
|
| + return png_gamma_16bit_correct(value, gamma_val);
|
| +#else
|
| + /* should not reach this */
|
| + return 0;
|
| +#endif /* 16BIT */
|
| +}
|
| +
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| +/* Internal function to build a single 16-bit table - the table consists of
|
| + * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
|
| + * to shift the input values right (or 16-number_of_signifiant_bits).
|
| + *
|
| + * The caller is responsible for ensuring that the table gets cleaned up on
|
| + * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
|
| + * should be somewhere that will be cleaned.
|
| + */
|
| +static void
|
| +png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
|
| + PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
|
| +{
|
| + /* Various values derived from 'shift': */
|
| + PNG_CONST unsigned int num = 1U << (8U - shift);
|
| +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + /* CSE the division and work round wacky GCC warnings (see the comments
|
| + * in png_gamma_8bit_correct for where these come from.)
|
| + */
|
| + PNG_CONST double fmax = 1./(((png_int_32)1 << (16U - shift))-1);
|
| +#endif
|
| + PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
|
| + PNG_CONST unsigned int max_by_2 = 1U << (15U-shift);
|
| + unsigned int i;
|
| +
|
| + png_uint_16pp table = *ptable =
|
| + (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
|
| +
|
| + for (i = 0; i < num; i++)
|
| + {
|
| + png_uint_16p sub_table = table[i] =
|
| + (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16)));
|
| +
|
| + /* The 'threshold' test is repeated here because it can arise for one of
|
| + * the 16-bit tables even if the others don't hit it.
|
| + */
|
| + if (png_gamma_significant(gamma_val) != 0)
|
| + {
|
| + /* The old code would overflow at the end and this would cause the
|
| + * 'pow' function to return a result >1, resulting in an
|
| + * arithmetic error. This code follows the spec exactly; ig is
|
| + * the recovered input sample, it always has 8-16 bits.
|
| + *
|
| + * We want input * 65535/max, rounded, the arithmetic fits in 32
|
| + * bits (unsigned) so long as max <= 32767.
|
| + */
|
| + unsigned int j;
|
| + for (j = 0; j < 256; j++)
|
| + {
|
| + png_uint_32 ig = (j << (8-shift)) + i;
|
| +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
|
| + /* Inline the 'max' scaling operation: */
|
| + /* See png_gamma_8bit_correct for why the cast to (int) is
|
| + * required here.
|
| + */
|
| + double d = floor(65535.*pow(ig*fmax, gamma_val*.00001)+.5);
|
| + sub_table[j] = (png_uint_16)d;
|
| +# else
|
| + if (shift != 0)
|
| + ig = (ig * 65535U + max_by_2)/max;
|
| +
|
| + sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
|
| +# endif
|
| + }
|
| + }
|
| + else
|
| + {
|
| + /* We must still build a table, but do it the fast way. */
|
| + unsigned int j;
|
| +
|
| + for (j = 0; j < 256; j++)
|
| + {
|
| + png_uint_32 ig = (j << (8-shift)) + i;
|
| +
|
| + if (shift != 0)
|
| + ig = (ig * 65535U + max_by_2)/max;
|
| +
|
| + sub_table[j] = (png_uint_16)ig;
|
| + }
|
| + }
|
| + }
|
| +}
|
| +
|
| +/* NOTE: this function expects the *inverse* of the overall gamma transformation
|
| + * required.
|
| + */
|
| +static void
|
| +png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,
|
| + PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
|
| +{
|
| + PNG_CONST unsigned int num = 1U << (8U - shift);
|
| + PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
|
| + unsigned int i;
|
| + png_uint_32 last;
|
| +
|
| + png_uint_16pp table = *ptable =
|
| + (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
|
| +
|
| + /* 'num' is the number of tables and also the number of low bits of low
|
| + * bits of the input 16-bit value used to select a table. Each table is
|
| + * itself indexed by the high 8 bits of the value.
|
| + */
|
| + for (i = 0; i < num; i++)
|
| + table[i] = (png_uint_16p)png_malloc(png_ptr,
|
| + 256 * (sizeof (png_uint_16)));
|
| +
|
| + /* 'gamma_val' is set to the reciprocal of the value calculated above, so
|
| + * pow(out,g) is an *input* value. 'last' is the last input value set.
|
| + *
|
| + * In the loop 'i' is used to find output values. Since the output is
|
| + * 8-bit there are only 256 possible values. The tables are set up to
|
| + * select the closest possible output value for each input by finding
|
| + * the input value at the boundary between each pair of output values
|
| + * and filling the table up to that boundary with the lower output
|
| + * value.
|
| + *
|
| + * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit
|
| + * values the code below uses a 16-bit value in i; the values start at
|
| + * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
|
| + * entries are filled with 255). Start i at 128 and fill all 'last'
|
| + * table entries <= 'max'
|
| + */
|
| + last = 0;
|
| + for (i = 0; i < 255; ++i) /* 8-bit output value */
|
| + {
|
| + /* Find the corresponding maximum input value */
|
| + png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
|
| +
|
| + /* Find the boundary value in 16 bits: */
|
| + png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
|
| +
|
| + /* Adjust (round) to (16-shift) bits: */
|
| + bound = (bound * max + 32768U)/65535U + 1U;
|
| +
|
| + while (last < bound)
|
| + {
|
| + table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
|
| + last++;
|
| + }
|
| + }
|
| +
|
| + /* And fill in the final entries. */
|
| + while (last < (num << 8))
|
| + {
|
| + table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
|
| + last++;
|
| + }
|
| +}
|
| +#endif /* 16BIT */
|
| +
|
| +/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
|
| + * typically much faster). Note that libpng currently does no sBIT processing
|
| + * (apparently contrary to the spec) so a 256-entry table is always generated.
|
| + */
|
| +static void
|
| +png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
|
| + PNG_CONST png_fixed_point gamma_val)
|
| +{
|
| + unsigned int i;
|
| + png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
|
| +
|
| + if (png_gamma_significant(gamma_val) != 0)
|
| + for (i=0; i<256; i++)
|
| + table[i] = png_gamma_8bit_correct(i, gamma_val);
|
| +
|
| + else
|
| + for (i=0; i<256; ++i)
|
| + table[i] = (png_byte)(i & 0xff);
|
| +}
|
| +
|
| +/* Used from png_read_destroy and below to release the memory used by the gamma
|
| + * tables.
|
| + */
|
| +void /* PRIVATE */
|
| +png_destroy_gamma_table(png_structrp png_ptr)
|
| +{
|
| + png_free(png_ptr, png_ptr->gamma_table);
|
| + png_ptr->gamma_table = NULL;
|
| +
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| + if (png_ptr->gamma_16_table != NULL)
|
| + {
|
| + int i;
|
| + int istop = (1 << (8 - png_ptr->gamma_shift));
|
| + for (i = 0; i < istop; i++)
|
| + {
|
| + png_free(png_ptr, png_ptr->gamma_16_table[i]);
|
| + }
|
| + png_free(png_ptr, png_ptr->gamma_16_table);
|
| + png_ptr->gamma_16_table = NULL;
|
| + }
|
| +#endif /* 16BIT */
|
| +
|
| +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
|
| + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
|
| + png_free(png_ptr, png_ptr->gamma_from_1);
|
| + png_ptr->gamma_from_1 = NULL;
|
| + png_free(png_ptr, png_ptr->gamma_to_1);
|
| + png_ptr->gamma_to_1 = NULL;
|
| +
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| + if (png_ptr->gamma_16_from_1 != NULL)
|
| + {
|
| + int i;
|
| + int istop = (1 << (8 - png_ptr->gamma_shift));
|
| + for (i = 0; i < istop; i++)
|
| + {
|
| + png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
|
| + }
|
| + png_free(png_ptr, png_ptr->gamma_16_from_1);
|
| + png_ptr->gamma_16_from_1 = NULL;
|
| + }
|
| + if (png_ptr->gamma_16_to_1 != NULL)
|
| + {
|
| + int i;
|
| + int istop = (1 << (8 - png_ptr->gamma_shift));
|
| + for (i = 0; i < istop; i++)
|
| + {
|
| + png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
|
| + }
|
| + png_free(png_ptr, png_ptr->gamma_16_to_1);
|
| + png_ptr->gamma_16_to_1 = NULL;
|
| + }
|
| +#endif /* 16BIT */
|
| +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
|
| +}
|
| +
|
| +/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
|
| + * tables, we don't make a full table if we are reducing to 8-bit in
|
| + * the future. Note also how the gamma_16 tables are segmented so that
|
| + * we don't need to allocate > 64K chunks for a full 16-bit table.
|
| + */
|
| +void /* PRIVATE */
|
| +png_build_gamma_table(png_structrp png_ptr, int bit_depth)
|
| +{
|
| + png_debug(1, "in png_build_gamma_table");
|
| +
|
| + /* Remove any existing table; this copes with multiple calls to
|
| + * png_read_update_info. The warning is because building the gamma tables
|
| + * multiple times is a performance hit - it's harmless but the ability to call
|
| + * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible
|
| + * to warn if the app introduces such a hit.
|
| + */
|
| + if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
|
| + {
|
| + png_warning(png_ptr, "gamma table being rebuilt");
|
| + png_destroy_gamma_table(png_ptr);
|
| + }
|
| +
|
| + if (bit_depth <= 8)
|
| + {
|
| + png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
|
| + png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
|
| + png_ptr->screen_gamma) : PNG_FP_1);
|
| +
|
| +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
|
| + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
|
| + if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
|
| + {
|
| + png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
|
| + png_reciprocal(png_ptr->colorspace.gamma));
|
| +
|
| + png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
|
| + png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
|
| + png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
|
| + }
|
| +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
|
| + }
|
| +#ifdef PNG_16BIT_SUPPORTED
|
| + else
|
| + {
|
| + png_byte shift, sig_bit;
|
| +
|
| + if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
| + {
|
| + sig_bit = png_ptr->sig_bit.red;
|
| +
|
| + if (png_ptr->sig_bit.green > sig_bit)
|
| + sig_bit = png_ptr->sig_bit.green;
|
| +
|
| + if (png_ptr->sig_bit.blue > sig_bit)
|
| + sig_bit = png_ptr->sig_bit.blue;
|
| + }
|
| + else
|
| + sig_bit = png_ptr->sig_bit.gray;
|
| +
|
| + /* 16-bit gamma code uses this equation:
|
| + *
|
| + * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
|
| + *
|
| + * Where 'iv' is the input color value and 'ov' is the output value -
|
| + * pow(iv, gamma).
|
| + *
|
| + * Thus the gamma table consists of up to 256 256-entry tables. The table
|
| + * is selected by the (8-gamma_shift) most significant of the low 8 bits of
|
| + * the color value then indexed by the upper 8 bits:
|
| + *
|
| + * table[low bits][high 8 bits]
|
| + *
|
| + * So the table 'n' corresponds to all those 'iv' of:
|
| + *
|
| + * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
|
| + *
|
| + */
|
| + if (sig_bit > 0 && sig_bit < 16U)
|
| + /* shift == insignificant bits */
|
| + shift = (png_byte)((16U - sig_bit) & 0xff);
|
| +
|
| + else
|
| + shift = 0; /* keep all 16 bits */
|
| +
|
| + if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
|
| + {
|
| + /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
|
| + * the significant bits in the *input* when the output will
|
| + * eventually be 8 bits. By default it is 11.
|
| + */
|
| + if (shift < (16U - PNG_MAX_GAMMA_8))
|
| + shift = (16U - PNG_MAX_GAMMA_8);
|
| + }
|
| +
|
| + if (shift > 8U)
|
| + shift = 8U; /* Guarantees at least one table! */
|
| +
|
| + png_ptr->gamma_shift = shift;
|
| +
|
| + /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
|
| + * PNG_COMPOSE). This effectively smashed the background calculation for
|
| + * 16-bit output because the 8-bit table assumes the result will be reduced
|
| + * to 8 bits.
|
| + */
|
| + if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
|
| + png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
|
| + png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
|
| + png_ptr->screen_gamma) : PNG_FP_1);
|
| +
|
| + else
|
| + png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
|
| + png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
|
| + png_ptr->screen_gamma) : PNG_FP_1);
|
| +
|
| +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
|
| + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
|
| + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
|
| + if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
|
| + {
|
| + png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
|
| + png_reciprocal(png_ptr->colorspace.gamma));
|
| +
|
| + /* Notice that the '16 from 1' table should be full precision, however
|
| + * the lookup on this table still uses gamma_shift, so it can't be.
|
| + * TODO: fix this.
|
| + */
|
| + png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
|
| + png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
|
| + png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
|
| + }
|
| +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
|
| + }
|
| +#endif /* 16BIT */
|
| +}
|
| +#endif /* READ_GAMMA */
|
| +
|
| +/* HARDWARE OR SOFTWARE OPTION SUPPORT */
|
| +#ifdef PNG_SET_OPTION_SUPPORTED
|
| +int PNGAPI
|
| +png_set_option(png_structrp png_ptr, int option, int onoff)
|
| +{
|
| + if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
|
| + (option & 1) == 0)
|
| + {
|
| + int mask = 3 << option;
|
| + int setting = (2 + (onoff != 0)) << option;
|
| + int current = png_ptr->options;
|
| +
|
| + png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff);
|
| +
|
| + return (current & mask) >> option;
|
| + }
|
| +
|
| + return PNG_OPTION_INVALID;
|
| +}
|
| +#endif
|
| +
|
| +/* sRGB support */
|
| +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
|
| + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
|
| +/* sRGB conversion tables; these are machine generated with the code in
|
| + * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the
|
| + * specification (see the article at http://en.wikipedia.org/wiki/SRGB)
|
| + * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
|
| + * The sRGB to linear table is exact (to the nearest 16-bit linear fraction).
|
| + * The inverse (linear to sRGB) table has accuracies as follows:
|
| + *
|
| + * For all possible (255*65535+1) input values:
|
| + *
|
| + * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact
|
| + *
|
| + * For the input values corresponding to the 65536 16-bit values:
|
| + *
|
| + * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
|
| + *
|
| + * In all cases the inexact readings are only off by one.
|
| + */
|
| +
|
| +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
| +/* The convert-to-sRGB table is only currently required for read. */
|
| +const png_uint_16 png_sRGB_table[256] =
|
| +{
|
| + 0,20,40,60,80,99,119,139,
|
| + 159,179,199,219,241,264,288,313,
|
| + 340,367,396,427,458,491,526,562,
|
| + 599,637,677,718,761,805,851,898,
|
| + 947,997,1048,1101,1156,1212,1270,1330,
|
| + 1391,1453,1517,1583,1651,1720,1790,1863,
|
| + 1937,2013,2090,2170,2250,2333,2418,2504,
|
| + 2592,2681,2773,2866,2961,3058,3157,3258,
|
| + 3360,3464,3570,3678,3788,3900,4014,4129,
|
| + 4247,4366,4488,4611,4736,4864,4993,5124,
|
| + 5257,5392,5530,5669,5810,5953,6099,6246,
|
| + 6395,6547,6700,6856,7014,7174,7335,7500,
|
| + 7666,7834,8004,8177,8352,8528,8708,8889,
|
| + 9072,9258,9445,9635,9828,10022,10219,10417,
|
| + 10619,10822,11028,11235,11446,11658,11873,12090,
|
| + 12309,12530,12754,12980,13209,13440,13673,13909,
|
| + 14146,14387,14629,14874,15122,15371,15623,15878,
|
| + 16135,16394,16656,16920,17187,17456,17727,18001,
|
| + 18277,18556,18837,19121,19407,19696,19987,20281,
|
| + 20577,20876,21177,21481,21787,22096,22407,22721,
|
| + 23038,23357,23678,24002,24329,24658,24990,25325,
|
| + 25662,26001,26344,26688,27036,27386,27739,28094,
|
| + 28452,28813,29176,29542,29911,30282,30656,31033,
|
| + 31412,31794,32179,32567,32957,33350,33745,34143,
|
| + 34544,34948,35355,35764,36176,36591,37008,37429,
|
| + 37852,38278,38706,39138,39572,40009,40449,40891,
|
| + 41337,41785,42236,42690,43147,43606,44069,44534,
|
| + 45002,45473,45947,46423,46903,47385,47871,48359,
|
| + 48850,49344,49841,50341,50844,51349,51858,52369,
|
| + 52884,53401,53921,54445,54971,55500,56032,56567,
|
| + 57105,57646,58190,58737,59287,59840,60396,60955,
|
| + 61517,62082,62650,63221,63795,64372,64952,65535
|
| +};
|
| +#endif /* SIMPLIFIED_READ */
|
| +
|
| +/* The base/delta tables are required for both read and write (but currently
|
| + * only the simplified versions.)
|
| + */
|
| +const png_uint_16 png_sRGB_base[512] =
|
| +{
|
| + 128,1782,3383,4644,5675,6564,7357,8074,
|
| + 8732,9346,9921,10463,10977,11466,11935,12384,
|
| + 12816,13233,13634,14024,14402,14769,15125,15473,
|
| + 15812,16142,16466,16781,17090,17393,17690,17981,
|
| + 18266,18546,18822,19093,19359,19621,19879,20133,
|
| + 20383,20630,20873,21113,21349,21583,21813,22041,
|
| + 22265,22487,22707,22923,23138,23350,23559,23767,
|
| + 23972,24175,24376,24575,24772,24967,25160,25352,
|
| + 25542,25730,25916,26101,26284,26465,26645,26823,
|
| + 27000,27176,27350,27523,27695,27865,28034,28201,
|
| + 28368,28533,28697,28860,29021,29182,29341,29500,
|
| + 29657,29813,29969,30123,30276,30429,30580,30730,
|
| + 30880,31028,31176,31323,31469,31614,31758,31902,
|
| + 32045,32186,32327,32468,32607,32746,32884,33021,
|
| + 33158,33294,33429,33564,33697,33831,33963,34095,
|
| + 34226,34357,34486,34616,34744,34873,35000,35127,
|
| + 35253,35379,35504,35629,35753,35876,35999,36122,
|
| + 36244,36365,36486,36606,36726,36845,36964,37083,
|
| + 37201,37318,37435,37551,37668,37783,37898,38013,
|
| + 38127,38241,38354,38467,38580,38692,38803,38915,
|
| + 39026,39136,39246,39356,39465,39574,39682,39790,
|
| + 39898,40005,40112,40219,40325,40431,40537,40642,
|
| + 40747,40851,40955,41059,41163,41266,41369,41471,
|
| + 41573,41675,41777,41878,41979,42079,42179,42279,
|
| + 42379,42478,42577,42676,42775,42873,42971,43068,
|
| + 43165,43262,43359,43456,43552,43648,43743,43839,
|
| + 43934,44028,44123,44217,44311,44405,44499,44592,
|
| + 44685,44778,44870,44962,45054,45146,45238,45329,
|
| + 45420,45511,45601,45692,45782,45872,45961,46051,
|
| + 46140,46229,46318,46406,46494,46583,46670,46758,
|
| + 46846,46933,47020,47107,47193,47280,47366,47452,
|
| + 47538,47623,47709,47794,47879,47964,48048,48133,
|
| + 48217,48301,48385,48468,48552,48635,48718,48801,
|
| + 48884,48966,49048,49131,49213,49294,49376,49458,
|
| + 49539,49620,49701,49782,49862,49943,50023,50103,
|
| + 50183,50263,50342,50422,50501,50580,50659,50738,
|
| + 50816,50895,50973,51051,51129,51207,51285,51362,
|
| + 51439,51517,51594,51671,51747,51824,51900,51977,
|
| + 52053,52129,52205,52280,52356,52432,52507,52582,
|
| + 52657,52732,52807,52881,52956,53030,53104,53178,
|
| + 53252,53326,53400,53473,53546,53620,53693,53766,
|
| + 53839,53911,53984,54056,54129,54201,54273,54345,
|
| + 54417,54489,54560,54632,54703,54774,54845,54916,
|
| + 54987,55058,55129,55199,55269,55340,55410,55480,
|
| + 55550,55620,55689,55759,55828,55898,55967,56036,
|
| + 56105,56174,56243,56311,56380,56448,56517,56585,
|
| + 56653,56721,56789,56857,56924,56992,57059,57127,
|
| + 57194,57261,57328,57395,57462,57529,57595,57662,
|
| + 57728,57795,57861,57927,57993,58059,58125,58191,
|
| + 58256,58322,58387,58453,58518,58583,58648,58713,
|
| + 58778,58843,58908,58972,59037,59101,59165,59230,
|
| + 59294,59358,59422,59486,59549,59613,59677,59740,
|
| + 59804,59867,59930,59993,60056,60119,60182,60245,
|
| + 60308,60370,60433,60495,60558,60620,60682,60744,
|
| + 60806,60868,60930,60992,61054,61115,61177,61238,
|
| + 61300,61361,61422,61483,61544,61605,61666,61727,
|
| + 61788,61848,61909,61969,62030,62090,62150,62211,
|
| + 62271,62331,62391,62450,62510,62570,62630,62689,
|
| + 62749,62808,62867,62927,62986,63045,63104,63163,
|
| + 63222,63281,63340,63398,63457,63515,63574,63632,
|
| + 63691,63749,63807,63865,63923,63981,64039,64097,
|
| + 64155,64212,64270,64328,64385,64443,64500,64557,
|
| + 64614,64672,64729,64786,64843,64900,64956,65013,
|
| + 65070,65126,65183,65239,65296,65352,65409,65465
|
| +};
|
| +
|
| +const png_byte png_sRGB_delta[512] =
|
| +{
|
| + 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54,
|
| + 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36,
|
| + 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28,
|
| + 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24,
|
| + 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21,
|
| + 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19,
|
| + 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17,
|
| + 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16,
|
| + 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15,
|
| + 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14,
|
| + 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13,
|
| + 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12,
|
| + 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
|
| + 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11,
|
| + 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
|
| + 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
|
| + 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
|
| + 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
|
| + 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
|
| + 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
|
| + 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
|
| + 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,
|
| + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
|
| + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
|
| + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
|
| +};
|
| +#endif /* SIMPLIFIED READ/WRITE sRGB support */
|
| +
|
| +/* SIMPLIFIED READ/WRITE SUPPORT */
|
| +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
|
| + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
|
| +static int
|
| +png_image_free_function(png_voidp argument)
|
| +{
|
| + png_imagep image = png_voidcast(png_imagep, argument);
|
| + png_controlp cp = image->opaque;
|
| + png_control c;
|
| +
|
| + /* Double check that we have a png_ptr - it should be impossible to get here
|
| + * without one.
|
| + */
|
| + if (cp->png_ptr == NULL)
|
| + return 0;
|
| +
|
| + /* First free any data held in the control structure. */
|
| +# ifdef PNG_STDIO_SUPPORTED
|
| + if (cp->owned_file != 0)
|
| + {
|
| + FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
|
| + cp->owned_file = 0;
|
| +
|
| + /* Ignore errors here. */
|
| + if (fp != NULL)
|
| + {
|
| + cp->png_ptr->io_ptr = NULL;
|
| + (void)fclose(fp);
|
| + }
|
| + }
|
| +# endif
|
| +
|
| + /* Copy the control structure so that the original, allocated, version can be
|
| + * safely freed. Notice that a png_error here stops the remainder of the
|
| + * cleanup, but this is probably fine because that would indicate bad memory
|
| + * problems anyway.
|
| + */
|
| + c = *cp;
|
| + image->opaque = &c;
|
| + png_free(c.png_ptr, cp);
|
| +
|
| + /* Then the structures, calling the correct API. */
|
| + if (c.for_write != 0)
|
| + {
|
| +# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
|
| + png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
|
| +# else
|
| + png_error(c.png_ptr, "simplified write not supported");
|
| +# endif
|
| + }
|
| + else
|
| + {
|
| +# ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
| + png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL);
|
| +# else
|
| + png_error(c.png_ptr, "simplified read not supported");
|
| +# endif
|
| + }
|
| +
|
| + /* Success. */
|
| + return 1;
|
| +}
|
| +
|
| +void PNGAPI
|
| +png_image_free(png_imagep image)
|
| +{
|
| + /* Safely call the real function, but only if doing so is safe at this point
|
| + * (if not inside an error handling context). Otherwise assume
|
| + * png_safe_execute will call this API after the return.
|
| + */
|
| + if (image != NULL && image->opaque != NULL &&
|
| + image->opaque->error_buf == NULL)
|
| + {
|
| + /* Ignore errors here: */
|
| + (void)png_safe_execute(image, png_image_free_function, image);
|
| + image->opaque = NULL;
|
| + }
|
| +}
|
| +
|
| +int /* PRIVATE */
|
| +png_image_error(png_imagep image, png_const_charp error_message)
|
| +{
|
| + /* Utility to log an error. */
|
| + png_safecat(image->message, (sizeof image->message), 0, error_message);
|
| + image->warning_or_error |= PNG_IMAGE_ERROR;
|
| + png_image_free(image);
|
| + return 0;
|
| +}
|
| +
|
| +#endif /* SIMPLIFIED READ/WRITE */
|
| +#endif /* READ || WRITE */
|
|
|
Chromium Code Reviews
Issue 1591483003:
XFA: Upgrade libpng to 1.6.20. (Closed)
Base URL: https://pdfium.googlesource.com/pdfium.git@xfa