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Unified Diff: third_party/libpng/pngpread.c

Issue 1591483003: XFA: Upgrade libpng to 1.6.20. (Closed) Base URL: https://pdfium.googlesource.com/pdfium.git@xfa
Patch Set: rebase Created 4 years, 11 months ago
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Index: third_party/libpng/pngpread.c
diff --git a/third_party/lpng_v163/pngpread.c b/third_party/libpng/pngpread.c
similarity index 74%
rename from third_party/lpng_v163/pngpread.c
rename to third_party/libpng/pngpread.c
index afb2abf3578fc4abcfaa723f337ca7298447d910..89ffc4018f6826a7931072bde8eb4180cbbe2ade 100644
--- a/third_party/lpng_v163/pngpread.c
+++ b/third_party/libpng/pngpread.c
@@ -1,1290 +1,1085 @@
-/* pngpread.c - read a png file in push mode
- *
- * Last changed in libpng 1.6.0 [February 14, 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"
-
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-
-/* Push model modes */
-#define PNG_READ_SIG_MODE 0
-#define PNG_READ_CHUNK_MODE 1
-#define PNG_READ_IDAT_MODE 2
-#define PNG_SKIP_MODE 3
-#define PNG_READ_tEXt_MODE 4
-#define PNG_READ_zTXt_MODE 5
-#define PNG_READ_DONE_MODE 6
-#define PNG_READ_iTXt_MODE 7
-#define PNG_ERROR_MODE 8
-
-void PNGAPI
-png_process_data(png_structrp png_ptr, png_inforp info_ptr,
- png_bytep buffer, png_size_t buffer_size)
-{
- if (png_ptr == NULL || info_ptr == NULL)
- return;
-
- png_push_restore_buffer(png_ptr, buffer, buffer_size);
-
- while (png_ptr->buffer_size)
- {
- png_process_some_data(png_ptr, info_ptr);
- }
-}
-
-png_size_t PNGAPI
-png_process_data_pause(png_structrp png_ptr, int save)
-{
- if (png_ptr != NULL)
- {
- /* It's easiest for the caller if we do the save, then the caller doesn't
- * have to supply the same data again:
- */
- if (save)
- png_push_save_buffer(png_ptr);
- else
- {
- /* This includes any pending saved bytes: */
- png_size_t remaining = png_ptr->buffer_size;
- png_ptr->buffer_size = 0;
-
- /* So subtract the saved buffer size, unless all the data
- * is actually 'saved', in which case we just return 0
- */
- if (png_ptr->save_buffer_size < remaining)
- return remaining - png_ptr->save_buffer_size;
- }
- }
-
- return 0;
-}
-
-png_uint_32 PNGAPI
-png_process_data_skip(png_structrp png_ptr)
-{
- png_uint_32 remaining = 0;
-
- if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
- png_ptr->skip_length > 0)
- {
- /* At the end of png_process_data the buffer size must be 0 (see the loop
- * above) so we can detect a broken call here:
- */
- if (png_ptr->buffer_size != 0)
- png_error(png_ptr,
- "png_process_data_skip called inside png_process_data");
-
- /* If is impossible for there to be a saved buffer at this point -
- * otherwise we could not be in SKIP mode. This will also happen if
- * png_process_skip is called inside png_process_data (but only very
- * rarely.)
- */
- if (png_ptr->save_buffer_size != 0)
- png_error(png_ptr, "png_process_data_skip called with saved data");
-
- remaining = png_ptr->skip_length;
- png_ptr->skip_length = 0;
- png_ptr->process_mode = PNG_READ_CHUNK_MODE;
- }
-
- return remaining;
-}
-
-/* What we do with the incoming data depends on what we were previously
- * doing before we ran out of data...
- */
-void /* PRIVATE */
-png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
-{
- if (png_ptr == NULL)
- return;
-
- switch (png_ptr->process_mode)
- {
- case PNG_READ_SIG_MODE:
- {
- png_push_read_sig(png_ptr, info_ptr);
- break;
- }
-
- case PNG_READ_CHUNK_MODE:
- {
- png_push_read_chunk(png_ptr, info_ptr);
- break;
- }
-
- case PNG_READ_IDAT_MODE:
- {
- png_push_read_IDAT(png_ptr);
- break;
- }
-
- case PNG_SKIP_MODE:
- {
- png_push_crc_finish(png_ptr);
- break;
- }
-
- default:
- {
- png_ptr->buffer_size = 0;
- break;
- }
- }
-}
-
-/* Read any remaining signature bytes from the stream and compare them with
- * the correct PNG signature. It is possible that this routine is called
- * with bytes already read from the signature, either because they have been
- * checked by the calling application, or because of multiple calls to this
- * routine.
- */
-void /* PRIVATE */
-png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
-{
- png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */
- num_to_check = 8 - num_checked;
-
- if (png_ptr->buffer_size < num_to_check)
- {
- num_to_check = png_ptr->buffer_size;
- }
-
- png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
- num_to_check);
- png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
-
- if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
- {
- if (num_checked < 4 &&
- png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
- png_error(png_ptr, "Not a PNG file");
-
- else
- png_error(png_ptr, "PNG file corrupted by ASCII conversion");
- }
- else
- {
- if (png_ptr->sig_bytes >= 8)
- {
- png_ptr->process_mode = PNG_READ_CHUNK_MODE;
- }
- }
-}
-
-void /* PRIVATE */
-png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
-{
- png_uint_32 chunk_name;
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- int keep; /* unknown handling method */
-#endif
-
- /* First we make sure we have enough data for the 4 byte chunk name
- * and the 4 byte chunk length before proceeding with decoding the
- * chunk data. To fully decode each of these chunks, we also make
- * sure we have enough data in the buffer for the 4 byte CRC at the
- * end of every chunk (except IDAT, which is handled separately).
- */
- if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
- {
- png_byte chunk_length[4];
- png_byte chunk_tag[4];
-
- if (png_ptr->buffer_size < 8)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_push_fill_buffer(png_ptr, chunk_length, 4);
- png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
- png_reset_crc(png_ptr);
- png_crc_read(png_ptr, chunk_tag, 4);
- png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
- png_check_chunk_name(png_ptr, png_ptr->chunk_name);
- png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
- }
-
- chunk_name = png_ptr->chunk_name;
-
- if (chunk_name == png_IDAT)
- {
- if (png_ptr->mode & PNG_AFTER_IDAT)
- png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
-
- /* If we reach an IDAT chunk, this means we have read all of the
- * header chunks, and we can start reading the image (or if this
- * is called after the image has been read - we have an error).
- */
- if (!(png_ptr->mode & PNG_HAVE_IHDR))
- png_error(png_ptr, "Missing IHDR before IDAT");
-
- else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
- !(png_ptr->mode & PNG_HAVE_PLTE))
- png_error(png_ptr, "Missing PLTE before IDAT");
-
- png_ptr->mode |= PNG_HAVE_IDAT;
-
- if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
- if (png_ptr->push_length == 0)
- return;
-
- if (png_ptr->mode & PNG_AFTER_IDAT)
- png_benign_error(png_ptr, "Too many IDATs found");
- }
-
- if (chunk_name == png_IHDR)
- {
- if (png_ptr->push_length != 13)
- png_error(png_ptr, "Invalid IHDR length");
-
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
- }
-
- else if (chunk_name == png_IEND)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
-
- png_ptr->process_mode = PNG_READ_DONE_MODE;
- png_push_have_end(png_ptr, info_ptr);
- }
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
-
- if (chunk_name == png_PLTE)
- png_ptr->mode |= PNG_HAVE_PLTE;
- }
-
-#endif
- else if (chunk_name == png_PLTE)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
- png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
- }
-
- else if (chunk_name == png_IDAT)
- {
- png_ptr->idat_size = png_ptr->push_length;
- png_ptr->process_mode = PNG_READ_IDAT_MODE;
- png_push_have_info(png_ptr, info_ptr);
- png_ptr->zstream.avail_out =
- (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
- png_ptr->iwidth) + 1;
- png_ptr->zstream.next_out = png_ptr->row_buf;
- return;
- }
-
-#ifdef PNG_READ_gAMA_SUPPORTED
- else if (png_ptr->chunk_name == png_gAMA)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
- else if (png_ptr->chunk_name == png_sBIT)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
- else if (png_ptr->chunk_name == png_cHRM)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
- else if (chunk_name == png_sRGB)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
- else if (png_ptr->chunk_name == png_iCCP)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
- else if (chunk_name == png_sPLT)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
- else if (chunk_name == png_tRNS)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_bKGD_SUPPORTED
- else if (chunk_name == png_bKGD)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
- else if (chunk_name == png_hIST)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
- else if (chunk_name == png_pHYs)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
- else if (chunk_name == png_oFFs)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
- }
-#endif
-
-#ifdef PNG_READ_pCAL_SUPPORTED
- else if (chunk_name == png_pCAL)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
- else if (chunk_name == png_sCAL)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
- else if (chunk_name == png_tIME)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
- else if (chunk_name == png_tEXt)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
- else if (chunk_name == png_zTXt)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
- else if (chunk_name == png_iTXt)
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
- }
-
-#endif
- else
- {
- if (png_ptr->push_length + 4 > png_ptr->buffer_size)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
- png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
- PNG_HANDLE_CHUNK_AS_DEFAULT);
- }
-
- png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
-}
-
-void /* PRIVATE */
-png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
-{
- png_ptr->process_mode = PNG_SKIP_MODE;
- png_ptr->skip_length = skip;
-}
-
-void /* PRIVATE */
-png_push_crc_finish(png_structrp png_ptr)
-{
- if (png_ptr->skip_length && png_ptr->save_buffer_size)
- {
- png_size_t save_size = png_ptr->save_buffer_size;
- png_uint_32 skip_length = png_ptr->skip_length;
-
- /* We want the smaller of 'skip_length' and 'save_buffer_size', but
- * they are of different types and we don't know which variable has the
- * fewest bits. Carefully select the smaller and cast it to the type of
- * the larger - this cannot overflow. Do not cast in the following test
- * - it will break on either 16 or 64 bit platforms.
- */
- if (skip_length < save_size)
- save_size = (png_size_t)skip_length;
-
- else
- skip_length = (png_uint_32)save_size;
-
- png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
- png_ptr->skip_length -= skip_length;
- png_ptr->buffer_size -= save_size;
- png_ptr->save_buffer_size -= save_size;
- png_ptr->save_buffer_ptr += save_size;
- }
- if (png_ptr->skip_length && png_ptr->current_buffer_size)
- {
- png_size_t save_size = png_ptr->current_buffer_size;
- png_uint_32 skip_length = png_ptr->skip_length;
-
- /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
- * the same problem exists as above and the same solution.
- */
- if (skip_length < save_size)
- save_size = (png_size_t)skip_length;
-
- else
- skip_length = (png_uint_32)save_size;
-
- png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
- png_ptr->skip_length -= skip_length;
- png_ptr->buffer_size -= save_size;
- png_ptr->current_buffer_size -= save_size;
- png_ptr->current_buffer_ptr += save_size;
- }
- if (!png_ptr->skip_length)
- {
- if (png_ptr->buffer_size < 4)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_crc_finish(png_ptr, 0);
- png_ptr->process_mode = PNG_READ_CHUNK_MODE;
- }
-}
-
-void PNGCBAPI
-png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
-{
- png_bytep ptr;
-
- if (png_ptr == NULL)
- return;
-
- ptr = buffer;
- if (png_ptr->save_buffer_size)
- {
- png_size_t save_size;
-
- if (length < png_ptr->save_buffer_size)
- save_size = length;
-
- else
- save_size = png_ptr->save_buffer_size;
-
- memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
- length -= save_size;
- ptr += save_size;
- png_ptr->buffer_size -= save_size;
- png_ptr->save_buffer_size -= save_size;
- png_ptr->save_buffer_ptr += save_size;
- }
- if (length && png_ptr->current_buffer_size)
- {
- png_size_t save_size;
-
- if (length < png_ptr->current_buffer_size)
- save_size = length;
-
- else
- save_size = png_ptr->current_buffer_size;
-
- memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
- png_ptr->buffer_size -= save_size;
- png_ptr->current_buffer_size -= save_size;
- png_ptr->current_buffer_ptr += save_size;
- }
-}
-
-void /* PRIVATE */
-png_push_save_buffer(png_structrp png_ptr)
-{
- if (png_ptr->save_buffer_size)
- {
- if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
- {
- png_size_t i, istop;
- png_bytep sp;
- png_bytep dp;
-
- istop = png_ptr->save_buffer_size;
- for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
- i < istop; i++, sp++, dp++)
- {
- *dp = *sp;
- }
- }
- }
- if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
- png_ptr->save_buffer_max)
- {
- png_size_t new_max;
- png_bytep old_buffer;
-
- if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
- (png_ptr->current_buffer_size + 256))
- {
- png_error(png_ptr, "Potential overflow of save_buffer");
- }
-
- new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
- old_buffer = png_ptr->save_buffer;
- png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
- (png_size_t)new_max);
-
- if (png_ptr->save_buffer == NULL)
- {
- png_free(png_ptr, old_buffer);
- png_error(png_ptr, "Insufficient memory for save_buffer");
- }
-
- memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
- png_free(png_ptr, old_buffer);
- png_ptr->save_buffer_max = new_max;
- }
- if (png_ptr->current_buffer_size)
- {
- memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
- png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
- png_ptr->save_buffer_size += png_ptr->current_buffer_size;
- png_ptr->current_buffer_size = 0;
- }
- png_ptr->save_buffer_ptr = png_ptr->save_buffer;
- png_ptr->buffer_size = 0;
-}
-
-void /* PRIVATE */
-png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
- png_size_t buffer_length)
-{
- png_ptr->current_buffer = buffer;
- png_ptr->current_buffer_size = buffer_length;
- png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
- png_ptr->current_buffer_ptr = png_ptr->current_buffer;
-}
-
-void /* PRIVATE */
-png_push_read_IDAT(png_structrp png_ptr)
-{
- if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
- {
- png_byte chunk_length[4];
- png_byte chunk_tag[4];
-
- /* TODO: this code can be commoned up with the same code in push_read */
- if (png_ptr->buffer_size < 8)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_push_fill_buffer(png_ptr, chunk_length, 4);
- png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
- png_reset_crc(png_ptr);
- png_crc_read(png_ptr, chunk_tag, 4);
- png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
- png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
-
- if (png_ptr->chunk_name != png_IDAT)
- {
- png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-
- if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
- png_error(png_ptr, "Not enough compressed data");
-
- return;
- }
-
- png_ptr->idat_size = png_ptr->push_length;
- }
-
- if (png_ptr->idat_size && png_ptr->save_buffer_size)
- {
- png_size_t save_size = png_ptr->save_buffer_size;
- png_uint_32 idat_size = png_ptr->idat_size;
-
- /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
- * are of different types and we don't know which variable has the fewest
- * bits. Carefully select the smaller and cast it to the type of the
- * larger - this cannot overflow. Do not cast in the following test - it
- * will break on either 16 or 64 bit platforms.
- */
- if (idat_size < save_size)
- save_size = (png_size_t)idat_size;
-
- else
- idat_size = (png_uint_32)save_size;
-
- png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
- png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
- png_ptr->idat_size -= idat_size;
- png_ptr->buffer_size -= save_size;
- png_ptr->save_buffer_size -= save_size;
- png_ptr->save_buffer_ptr += save_size;
- }
-
- if (png_ptr->idat_size && png_ptr->current_buffer_size)
- {
- png_size_t save_size = png_ptr->current_buffer_size;
- png_uint_32 idat_size = png_ptr->idat_size;
-
- /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
- * are of different types and we don't know which variable has the fewest
- * bits. Carefully select the smaller and cast it to the type of the
- * larger - this cannot overflow.
- */
- if (idat_size < save_size)
- save_size = (png_size_t)idat_size;
-
- else
- idat_size = (png_uint_32)save_size;
-
- png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
- png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
- png_ptr->idat_size -= idat_size;
- png_ptr->buffer_size -= save_size;
- png_ptr->current_buffer_size -= save_size;
- png_ptr->current_buffer_ptr += save_size;
- }
- if (!png_ptr->idat_size)
- {
- if (png_ptr->buffer_size < 4)
- {
- png_push_save_buffer(png_ptr);
- return;
- }
-
- png_crc_finish(png_ptr, 0);
- png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
- png_ptr->mode |= PNG_AFTER_IDAT;
- png_ptr->zowner = 0;
- }
-}
-
-void /* PRIVATE */
-png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
- png_size_t buffer_length)
-{
- /* The caller checks for a non-zero buffer length. */
- if (!(buffer_length > 0) || buffer == NULL)
- png_error(png_ptr, "No IDAT data (internal error)");
-
- /* This routine must process all the data it has been given
- * before returning, calling the row callback as required to
- * handle the uncompressed results.
- */
- png_ptr->zstream.next_in = buffer;
- /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
- png_ptr->zstream.avail_in = (uInt)buffer_length;
-
- /* Keep going until the decompressed data is all processed
- * or the stream marked as finished.
- */
- while (png_ptr->zstream.avail_in > 0 &&
- !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
- {
- int ret;
-
- /* We have data for zlib, but we must check that zlib
- * has someplace to put the results. It doesn't matter
- * if we don't expect any results -- it may be the input
- * data is just the LZ end code.
- */
- if (!(png_ptr->zstream.avail_out > 0))
- {
- /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
- png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
- png_ptr->iwidth) + 1);
-
- png_ptr->zstream.next_out = png_ptr->row_buf;
- }
-
- /* Using Z_SYNC_FLUSH here means that an unterminated
- * LZ stream (a stream with a missing end code) can still
- * be handled, otherwise (Z_NO_FLUSH) a future zlib
- * implementation might defer output and therefore
- * change the current behavior (see comments in inflate.c
- * for why this doesn't happen at present with zlib 1.2.5).
- */
- ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
-
- /* Check for any failure before proceeding. */
- if (ret != Z_OK && ret != Z_STREAM_END)
- {
- /* Terminate the decompression. */
- png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
- png_ptr->zowner = 0;
-
- /* This may be a truncated stream (missing or
- * damaged end code). Treat that as a warning.
- */
- if (png_ptr->row_number >= png_ptr->num_rows ||
- png_ptr->pass > 6)
- png_warning(png_ptr, "Truncated compressed data in IDAT");
-
- else
- png_error(png_ptr, "Decompression error in IDAT");
-
- /* Skip the check on unprocessed input */
- return;
- }
-
- /* Did inflate output any data? */
- if (png_ptr->zstream.next_out != png_ptr->row_buf)
- {
- /* Is this unexpected data after the last row?
- * If it is, artificially terminate the LZ output
- * here.
- */
- if (png_ptr->row_number >= png_ptr->num_rows ||
- png_ptr->pass > 6)
- {
- /* Extra data. */
- png_warning(png_ptr, "Extra compressed data in IDAT");
- png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
- png_ptr->zowner = 0;
-
- /* Do no more processing; skip the unprocessed
- * input check below.
- */
- return;
- }
-
- /* Do we have a complete row? */
- if (png_ptr->zstream.avail_out == 0)
- png_push_process_row(png_ptr);
- }
-
- /* And check for the end of the stream. */
- if (ret == Z_STREAM_END)
- png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
- }
-
- /* All the data should have been processed, if anything
- * is left at this point we have bytes of IDAT data
- * after the zlib end code.
- */
- if (png_ptr->zstream.avail_in > 0)
- png_warning(png_ptr, "Extra compression data in IDAT");
-}
-
-void /* PRIVATE */
-png_push_process_row(png_structrp png_ptr)
-{
- /* 1.5.6: row_info moved out of png_struct to a local here. */
- png_row_info row_info;
-
- row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
- row_info.color_type = png_ptr->color_type;
- row_info.bit_depth = png_ptr->bit_depth;
- row_info.channels = png_ptr->channels;
- row_info.pixel_depth = png_ptr->pixel_depth;
- row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
-
- if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
- {
- if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
- png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
- png_ptr->prev_row + 1, png_ptr->row_buf[0]);
- else
- png_error(png_ptr, "bad adaptive filter value");
- }
-
- /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
- * 1.5.6, while the buffer really is this big in current versions of libpng
- * it may not be in the future, so this was changed just to copy the
- * interlaced row count:
- */
- memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
- if (png_ptr->transformations)
- png_do_read_transformations(png_ptr, &row_info);
-#endif
-
- /* The transformed pixel depth should match the depth now in row_info. */
- if (png_ptr->transformed_pixel_depth == 0)
- {
- png_ptr->transformed_pixel_depth = row_info.pixel_depth;
- if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
- png_error(png_ptr, "progressive row overflow");
- }
-
- else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
- png_error(png_ptr, "internal progressive row size calculation error");
-
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
- /* Blow up interlaced rows to full size */
- if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
- {
- if (png_ptr->pass < 6)
- png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
- png_ptr->transformations);
-
- switch (png_ptr->pass)
- {
- case 0:
- {
- int i;
- for (i = 0; i < 8 && png_ptr->pass == 0; i++)
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
- }
-
- if (png_ptr->pass == 2) /* Pass 1 might be empty */
- {
- for (i = 0; i < 4 && png_ptr->pass == 2; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
- }
-
- if (png_ptr->pass == 4 && png_ptr->height <= 4)
- {
- for (i = 0; i < 2 && png_ptr->pass == 4; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
- }
-
- if (png_ptr->pass == 6 && png_ptr->height <= 4)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
-
- break;
- }
-
- case 1:
- {
- int i;
- for (i = 0; i < 8 && png_ptr->pass == 1; i++)
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
- }
-
- if (png_ptr->pass == 2) /* Skip top 4 generated rows */
- {
- for (i = 0; i < 4 && png_ptr->pass == 2; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
- }
-
- break;
- }
-
- case 2:
- {
- int i;
-
- for (i = 0; i < 4 && png_ptr->pass == 2; i++)
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
- }
-
- for (i = 0; i < 4 && png_ptr->pass == 2; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
-
- if (png_ptr->pass == 4) /* Pass 3 might be empty */
- {
- for (i = 0; i < 2 && png_ptr->pass == 4; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
- }
-
- break;
- }
-
- case 3:
- {
- int i;
-
- for (i = 0; i < 4 && png_ptr->pass == 3; i++)
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
- }
-
- if (png_ptr->pass == 4) /* Skip top two generated rows */
- {
- for (i = 0; i < 2 && png_ptr->pass == 4; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
- }
-
- break;
- }
-
- case 4:
- {
- int i;
-
- for (i = 0; i < 2 && png_ptr->pass == 4; i++)
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
- }
-
- for (i = 0; i < 2 && png_ptr->pass == 4; i++)
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
-
- if (png_ptr->pass == 6) /* Pass 5 might be empty */
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
-
- break;
- }
-
- case 5:
- {
- int i;
-
- for (i = 0; i < 2 && png_ptr->pass == 5; i++)
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
- }
-
- if (png_ptr->pass == 6) /* Skip top generated row */
- {
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
-
- break;
- }
-
- default:
- case 6:
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
-
- if (png_ptr->pass != 6)
- break;
-
- png_push_have_row(png_ptr, NULL);
- png_read_push_finish_row(png_ptr);
- }
- }
- }
- else
-#endif
- {
- png_push_have_row(png_ptr, png_ptr->row_buf + 1);
- png_read_push_finish_row(png_ptr);
- }
-}
-
-void /* PRIVATE */
-png_read_push_finish_row(png_structrp png_ptr)
-{
-#ifdef PNG_READ_INTERLACING_SUPPORTED
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
-
- /* Height of interlace block. This is not currently used - if you need
- * it, uncomment it here and in png.h
- static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
- */
-#endif
-
- png_ptr->row_number++;
- if (png_ptr->row_number < png_ptr->num_rows)
- return;
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
- if (png_ptr->interlaced)
- {
- png_ptr->row_number = 0;
- memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
-
- do
- {
- png_ptr->pass++;
- if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
- (png_ptr->pass == 3 && png_ptr->width < 3) ||
- (png_ptr->pass == 5 && png_ptr->width < 2))
- png_ptr->pass++;
-
- if (png_ptr->pass > 7)
- png_ptr->pass--;
-
- if (png_ptr->pass >= 7)
- break;
-
- png_ptr->iwidth = (png_ptr->width +
- png_pass_inc[png_ptr->pass] - 1 -
- png_pass_start[png_ptr->pass]) /
- png_pass_inc[png_ptr->pass];
-
- if (png_ptr->transformations & PNG_INTERLACE)
- break;
-
- png_ptr->num_rows = (png_ptr->height +
- png_pass_yinc[png_ptr->pass] - 1 -
- png_pass_ystart[png_ptr->pass]) /
- png_pass_yinc[png_ptr->pass];
-
- } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
- }
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-}
-
-void /* PRIVATE */
-png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
-{
- if (png_ptr->info_fn != NULL)
- (*(png_ptr->info_fn))(png_ptr, info_ptr);
-}
-
-void /* PRIVATE */
-png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
-{
- if (png_ptr->end_fn != NULL)
- (*(png_ptr->end_fn))(png_ptr, info_ptr);
-}
-
-void /* PRIVATE */
-png_push_have_row(png_structrp png_ptr, png_bytep row)
-{
- if (png_ptr->row_fn != NULL)
- (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
- (int)png_ptr->pass);
-}
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
-void PNGAPI
-png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
- png_const_bytep new_row)
-{
- if (png_ptr == NULL)
- return;
-
- /* new_row is a flag here - if it is NULL then the app callback was called
- * from an empty row (see the calls to png_struct::row_fn below), otherwise
- * it must be png_ptr->row_buf+1
- */
- if (new_row != NULL)
- png_combine_row(png_ptr, old_row, 1/*display*/);
-}
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-
-void PNGAPI
-png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
- png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
- png_progressive_end_ptr end_fn)
-{
- if (png_ptr == NULL)
- return;
-
- png_ptr->info_fn = info_fn;
- png_ptr->row_fn = row_fn;
- png_ptr->end_fn = end_fn;
-
- png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
-}
-
-png_voidp PNGAPI
-png_get_progressive_ptr(png_const_structrp png_ptr)
-{
- if (png_ptr == NULL)
- return (NULL);
-
- return png_ptr->io_ptr;
-}
-#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+/* pngpread.c - read a png file in push mode
+ *
+ * Last changed in libpng 1.6.18 [July 23, 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"
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+
+/* Push model modes */
+#define PNG_READ_SIG_MODE 0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE 2
+#define PNG_READ_tEXt_MODE 4
+#define PNG_READ_zTXt_MODE 5
+#define PNG_READ_DONE_MODE 6
+#define PNG_READ_iTXt_MODE 7
+#define PNG_ERROR_MODE 8
+
+#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
+if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
+ { png_push_save_buffer(png_ptr); return; }
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
+if (png_ptr->buffer_size < N) \
+ { png_push_save_buffer(png_ptr); return; }
+
+void PNGAPI
+png_process_data(png_structrp png_ptr, png_inforp info_ptr,
+ png_bytep buffer, png_size_t buffer_size)
+{
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ png_push_restore_buffer(png_ptr, buffer, buffer_size);
+
+ while (png_ptr->buffer_size)
+ {
+ png_process_some_data(png_ptr, info_ptr);
+ }
+}
+
+png_size_t PNGAPI
+png_process_data_pause(png_structrp png_ptr, int save)
+{
+ if (png_ptr != NULL)
+ {
+ /* It's easiest for the caller if we do the save; then the caller doesn't
+ * have to supply the same data again:
+ */
+ if (save != 0)
+ png_push_save_buffer(png_ptr);
+ else
+ {
+ /* This includes any pending saved bytes: */
+ png_size_t remaining = png_ptr->buffer_size;
+ png_ptr->buffer_size = 0;
+
+ /* So subtract the saved buffer size, unless all the data
+ * is actually 'saved', in which case we just return 0
+ */
+ if (png_ptr->save_buffer_size < remaining)
+ return remaining - png_ptr->save_buffer_size;
+ }
+ }
+
+ return 0;
+}
+
+png_uint_32 PNGAPI
+png_process_data_skip(png_structrp png_ptr)
+{
+ /* TODO: Deprecate and remove this API.
+ * Somewhere the implementation of this seems to have been lost,
+ * or abandoned. It was only to support some internal back-door access
+ * to png_struct) in libpng-1.4.x.
+ */
+ png_app_warning(png_ptr,
+"png_process_data_skip is not implemented in any current version of libpng");
+ return 0;
+}
+
+/* What we do with the incoming data depends on what we were previously
+ * doing before we ran out of data...
+ */
+void /* PRIVATE */
+png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
+{
+ if (png_ptr == NULL)
+ return;
+
+ switch (png_ptr->process_mode)
+ {
+ case PNG_READ_SIG_MODE:
+ {
+ png_push_read_sig(png_ptr, info_ptr);
+ break;
+ }
+
+ case PNG_READ_CHUNK_MODE:
+ {
+ png_push_read_chunk(png_ptr, info_ptr);
+ break;
+ }
+
+ case PNG_READ_IDAT_MODE:
+ {
+ png_push_read_IDAT(png_ptr);
+ break;
+ }
+
+ default:
+ {
+ png_ptr->buffer_size = 0;
+ break;
+ }
+ }
+}
+
+/* Read any remaining signature bytes from the stream and compare them with
+ * the correct PNG signature. It is possible that this routine is called
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
+ */
+void /* PRIVATE */
+png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */
+ num_to_check = 8 - num_checked;
+
+ if (png_ptr->buffer_size < num_to_check)
+ {
+ num_to_check = png_ptr->buffer_size;
+ }
+
+ png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
+ num_to_check);
+ png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
+
+ if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
+ {
+ if (num_checked < 4 &&
+ png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+ png_error(png_ptr, "Not a PNG file");
+
+ else
+ png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+ }
+ else
+ {
+ if (png_ptr->sig_bytes >= 8)
+ {
+ png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+ }
+ }
+}
+
+void /* PRIVATE */
+png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_uint_32 chunk_name;
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ int keep; /* unknown handling method */
+#endif
+
+ /* First we make sure we have enough data for the 4-byte chunk name
+ * and the 4-byte chunk length before proceeding with decoding the
+ * chunk data. To fully decode each of these chunks, we also make
+ * sure we have enough data in the buffer for the 4-byte CRC at the
+ * end of every chunk (except IDAT, which is handled separately).
+ */
+ if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+ {
+ png_byte chunk_length[4];
+ png_byte chunk_tag[4];
+
+ PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+ png_push_fill_buffer(png_ptr, chunk_length, 4);
+ png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+ png_reset_crc(png_ptr);
+ png_crc_read(png_ptr, chunk_tag, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+ png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+ png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+ }
+
+ chunk_name = png_ptr->chunk_name;
+
+ if (chunk_name == png_IDAT)
+ {
+ if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+ png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+ /* If we reach an IDAT chunk, this means we have read all of the
+ * header chunks, and we can start reading the image (or if this
+ * is called after the image has been read - we have an error).
+ */
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_error(png_ptr, "Missing IHDR before IDAT");
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+ (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+ png_error(png_ptr, "Missing PLTE before IDAT");
+
+ png_ptr->mode |= PNG_HAVE_IDAT;
+ png_ptr->process_mode = PNG_READ_IDAT_MODE;
+
+ if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
+ if (png_ptr->push_length == 0)
+ return;
+
+ if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+ png_benign_error(png_ptr, "Too many IDATs found");
+ }
+
+ if (chunk_name == png_IHDR)
+ {
+ if (png_ptr->push_length != 13)
+ png_error(png_ptr, "Invalid IHDR length");
+
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+ else if (chunk_name == png_IEND)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
+
+ png_ptr->process_mode = PNG_READ_DONE_MODE;
+ png_push_have_end(png_ptr, info_ptr);
+ }
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
+
+ if (chunk_name == png_PLTE)
+ png_ptr->mode |= PNG_HAVE_PLTE;
+ }
+#endif
+
+ else if (chunk_name == png_PLTE)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+ else if (chunk_name == png_IDAT)
+ {
+ png_ptr->idat_size = png_ptr->push_length;
+ png_ptr->process_mode = PNG_READ_IDAT_MODE;
+ png_push_have_info(png_ptr, info_ptr);
+ png_ptr->zstream.avail_out =
+ (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
+ png_ptr->iwidth) + 1;
+ png_ptr->zstream.next_out = png_ptr->row_buf;
+ return;
+ }
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+ else if (png_ptr->chunk_name == png_gAMA)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sBIT_SUPPORTED
+ else if (png_ptr->chunk_name == png_sBIT)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_cHRM_SUPPORTED
+ else if (png_ptr->chunk_name == png_cHRM)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sRGB_SUPPORTED
+ else if (chunk_name == png_sRGB)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_iCCP_SUPPORTED
+ else if (png_ptr->chunk_name == png_iCCP)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sPLT_SUPPORTED
+ else if (chunk_name == png_sPLT)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_tRNS_SUPPORTED
+ else if (chunk_name == png_tRNS)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_bKGD_SUPPORTED
+ else if (chunk_name == png_bKGD)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_hIST_SUPPORTED
+ else if (chunk_name == png_hIST)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_pHYs_SUPPORTED
+ else if (chunk_name == png_pHYs)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_oFFs_SUPPORTED
+ else if (chunk_name == png_oFFs)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
+ }
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+ else if (chunk_name == png_pCAL)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sCAL_SUPPORTED
+ else if (chunk_name == png_sCAL)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_tIME_SUPPORTED
+ else if (chunk_name == png_tIME)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_tEXt_SUPPORTED
+ else if (chunk_name == png_tEXt)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_zTXt_SUPPORTED
+ else if (chunk_name == png_zTXt)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_iTXt_SUPPORTED
+ else if (chunk_name == png_iTXt)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+ }
+#endif
+
+ else
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
+ PNG_HANDLE_CHUNK_AS_DEFAULT);
+ }
+
+ png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+}
+
+void PNGCBAPI
+png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
+{
+ png_bytep ptr;
+
+ if (png_ptr == NULL)
+ return;
+
+ ptr = buffer;
+ if (png_ptr->save_buffer_size != 0)
+ {
+ png_size_t save_size;
+
+ if (length < png_ptr->save_buffer_size)
+ save_size = length;
+
+ else
+ save_size = png_ptr->save_buffer_size;
+
+ memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
+ length -= save_size;
+ ptr += save_size;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->save_buffer_size -= save_size;
+ png_ptr->save_buffer_ptr += save_size;
+ }
+ if (length != 0 && png_ptr->current_buffer_size != 0)
+ {
+ png_size_t save_size;
+
+ if (length < png_ptr->current_buffer_size)
+ save_size = length;
+
+ else
+ save_size = png_ptr->current_buffer_size;
+
+ memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
+ png_ptr->buffer_size -= save_size;
+ png_ptr->current_buffer_size -= save_size;
+ png_ptr->current_buffer_ptr += save_size;
+ }
+}
+
+void /* PRIVATE */
+png_push_save_buffer(png_structrp png_ptr)
+{
+ if (png_ptr->save_buffer_size != 0)
+ {
+ if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
+ {
+ png_size_t i, istop;
+ png_bytep sp;
+ png_bytep dp;
+
+ istop = png_ptr->save_buffer_size;
+ for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
+ i < istop; i++, sp++, dp++)
+ {
+ *dp = *sp;
+ }
+ }
+ }
+ if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
+ png_ptr->save_buffer_max)
+ {
+ png_size_t new_max;
+ png_bytep old_buffer;
+
+ if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
+ (png_ptr->current_buffer_size + 256))
+ {
+ png_error(png_ptr, "Potential overflow of save_buffer");
+ }
+
+ new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
+ old_buffer = png_ptr->save_buffer;
+ png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
+ (png_size_t)new_max);
+
+ if (png_ptr->save_buffer == NULL)
+ {
+ png_free(png_ptr, old_buffer);
+ png_error(png_ptr, "Insufficient memory for save_buffer");
+ }
+
+ memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+ png_free(png_ptr, old_buffer);
+ png_ptr->save_buffer_max = new_max;
+ }
+ if (png_ptr->current_buffer_size)
+ {
+ memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
+ png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
+ png_ptr->save_buffer_size += png_ptr->current_buffer_size;
+ png_ptr->current_buffer_size = 0;
+ }
+ png_ptr->save_buffer_ptr = png_ptr->save_buffer;
+ png_ptr->buffer_size = 0;
+}
+
+void /* PRIVATE */
+png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
+ png_size_t buffer_length)
+{
+ png_ptr->current_buffer = buffer;
+ png_ptr->current_buffer_size = buffer_length;
+ png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
+ png_ptr->current_buffer_ptr = png_ptr->current_buffer;
+}
+
+void /* PRIVATE */
+png_push_read_IDAT(png_structrp png_ptr)
+{
+ if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+ {
+ png_byte chunk_length[4];
+ png_byte chunk_tag[4];
+
+ /* TODO: this code can be commoned up with the same code in push_read */
+ PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+ png_push_fill_buffer(png_ptr, chunk_length, 4);
+ png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+ png_reset_crc(png_ptr);
+ png_crc_read(png_ptr, chunk_tag, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+ png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+
+ if (png_ptr->chunk_name != png_IDAT)
+ {
+ png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+ png_error(png_ptr, "Not enough compressed data");
+
+ return;
+ }
+
+ png_ptr->idat_size = png_ptr->push_length;
+ }
+
+ if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
+ {
+ png_size_t save_size = png_ptr->save_buffer_size;
+ png_uint_32 idat_size = png_ptr->idat_size;
+
+ /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+ * are of different types and we don't know which variable has the fewest
+ * bits. Carefully select the smaller and cast it to the type of the
+ * larger - this cannot overflow. Do not cast in the following test - it
+ * will break on either 16-bit or 64-bit platforms.
+ */
+ if (idat_size < save_size)
+ save_size = (png_size_t)idat_size;
+
+ else
+ idat_size = (png_uint_32)save_size;
+
+ png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+ png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+ png_ptr->idat_size -= idat_size;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->save_buffer_size -= save_size;
+ png_ptr->save_buffer_ptr += save_size;
+ }
+
+ if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
+ {
+ png_size_t save_size = png_ptr->current_buffer_size;
+ png_uint_32 idat_size = png_ptr->idat_size;
+
+ /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+ * are of different types and we don't know which variable has the fewest
+ * bits. Carefully select the smaller and cast it to the type of the
+ * larger - this cannot overflow.
+ */
+ if (idat_size < save_size)
+ save_size = (png_size_t)idat_size;
+
+ else
+ idat_size = (png_uint_32)save_size;
+
+ png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+ png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+ png_ptr->idat_size -= idat_size;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->current_buffer_size -= save_size;
+ png_ptr->current_buffer_ptr += save_size;
+ }
+
+ if (png_ptr->idat_size == 0)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+ png_crc_finish(png_ptr, 0);
+ png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+ png_ptr->mode |= PNG_AFTER_IDAT;
+ png_ptr->zowner = 0;
+ }
+}
+
+void /* PRIVATE */
+png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
+ png_size_t buffer_length)
+{
+ /* The caller checks for a non-zero buffer length. */
+ if (!(buffer_length > 0) || buffer == NULL)
+ png_error(png_ptr, "No IDAT data (internal error)");
+
+ /* This routine must process all the data it has been given
+ * before returning, calling the row callback as required to
+ * handle the uncompressed results.
+ */
+ png_ptr->zstream.next_in = buffer;
+ /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+ png_ptr->zstream.avail_in = (uInt)buffer_length;
+
+ /* Keep going until the decompressed data is all processed
+ * or the stream marked as finished.
+ */
+ while (png_ptr->zstream.avail_in > 0 &&
+ (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+ {
+ int ret;
+
+ /* We have data for zlib, but we must check that zlib
+ * has someplace to put the results. It doesn't matter
+ * if we don't expect any results -- it may be the input
+ * data is just the LZ end code.
+ */
+ if (!(png_ptr->zstream.avail_out > 0))
+ {
+ /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+ png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
+ png_ptr->iwidth) + 1);
+
+ png_ptr->zstream.next_out = png_ptr->row_buf;
+ }
+
+ /* Using Z_SYNC_FLUSH here means that an unterminated
+ * LZ stream (a stream with a missing end code) can still
+ * be handled, otherwise (Z_NO_FLUSH) a future zlib
+ * implementation might defer output and therefore
+ * change the current behavior (see comments in inflate.c
+ * for why this doesn't happen at present with zlib 1.2.5).
+ */
+ ret = PNG_INFLATE(png_ptr, Z_SYNC_FLUSH);
+
+ /* Check for any failure before proceeding. */
+ if (ret != Z_OK && ret != Z_STREAM_END)
+ {
+ /* Terminate the decompression. */
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ png_ptr->zowner = 0;
+
+ /* This may be a truncated stream (missing or
+ * damaged end code). Treat that as a warning.
+ */
+ if (png_ptr->row_number >= png_ptr->num_rows ||
+ png_ptr->pass > 6)
+ png_warning(png_ptr, "Truncated compressed data in IDAT");
+
+ else
+ png_error(png_ptr, "Decompression error in IDAT");
+
+ /* Skip the check on unprocessed input */
+ return;
+ }
+
+ /* Did inflate output any data? */
+ if (png_ptr->zstream.next_out != png_ptr->row_buf)
+ {
+ /* Is this unexpected data after the last row?
+ * If it is, artificially terminate the LZ output
+ * here.
+ */
+ if (png_ptr->row_number >= png_ptr->num_rows ||
+ png_ptr->pass > 6)
+ {
+ /* Extra data. */
+ png_warning(png_ptr, "Extra compressed data in IDAT");
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ png_ptr->zowner = 0;
+
+ /* Do no more processing; skip the unprocessed
+ * input check below.
+ */
+ return;
+ }
+
+ /* Do we have a complete row? */
+ if (png_ptr->zstream.avail_out == 0)
+ png_push_process_row(png_ptr);
+ }
+
+ /* And check for the end of the stream. */
+ if (ret == Z_STREAM_END)
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ }
+
+ /* All the data should have been processed, if anything
+ * is left at this point we have bytes of IDAT data
+ * after the zlib end code.
+ */
+ if (png_ptr->zstream.avail_in > 0)
+ png_warning(png_ptr, "Extra compression data in IDAT");
+}
+
+void /* PRIVATE */
+png_push_process_row(png_structrp png_ptr)
+{
+ /* 1.5.6: row_info moved out of png_struct to a local here. */
+ png_row_info row_info;
+
+ row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+ row_info.color_type = png_ptr->color_type;
+ row_info.bit_depth = png_ptr->bit_depth;
+ row_info.channels = png_ptr->channels;
+ row_info.pixel_depth = png_ptr->pixel_depth;
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+ if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+ {
+ if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+ png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+ else
+ png_error(png_ptr, "bad adaptive filter value");
+ }
+
+ /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+ * 1.5.6, while the buffer really is this big in current versions of libpng
+ * it may not be in the future, so this was changed just to copy the
+ * interlaced row count:
+ */
+ memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ if (png_ptr->transformations != 0)
+ png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+ /* The transformed pixel depth should match the depth now in row_info. */
+ if (png_ptr->transformed_pixel_depth == 0)
+ {
+ png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+ if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+ png_error(png_ptr, "progressive row overflow");
+ }
+
+ else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+ png_error(png_ptr, "internal progressive row size calculation error");
+
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* Expand interlaced rows to full size */
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ if (png_ptr->pass < 6)
+ png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+ png_ptr->transformations);
+
+ switch (png_ptr->pass)
+ {
+ case 0:
+ {
+ int i;
+ for (i = 0; i < 8 && png_ptr->pass == 0; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
+ }
+
+ if (png_ptr->pass == 2) /* Pass 1 might be empty */
+ {
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ if (png_ptr->pass == 4 && png_ptr->height <= 4)
+ {
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ if (png_ptr->pass == 6 && png_ptr->height <= 4)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ break;
+ }
+
+ case 1:
+ {
+ int i;
+ for (i = 0; i < 8 && png_ptr->pass == 1; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 2) /* Skip top 4 generated rows */
+ {
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ break;
+ }
+
+ case 2:
+ {
+ int i;
+
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 4) /* Pass 3 might be empty */
+ {
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ break;
+ }
+
+ case 3:
+ {
+ int i;
+
+ for (i = 0; i < 4 && png_ptr->pass == 3; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 4) /* Skip top two generated rows */
+ {
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ break;
+ }
+
+ case 4:
+ {
+ int i;
+
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 6) /* Pass 5 might be empty */
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ break;
+ }
+
+ case 5:
+ {
+ int i;
+
+ for (i = 0; i < 2 && png_ptr->pass == 5; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 6) /* Skip top generated row */
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ break;
+ }
+
+ default:
+ case 6:
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+
+ if (png_ptr->pass != 6)
+ break;
+
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+ }
+ else
+#endif
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+}
+
+void /* PRIVATE */
+png_read_push_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+ /* Height of interlace block. This is not currently used - if you need
+ * it, uncomment it here and in png.h
+ static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+ */
+#endif
+
+ png_ptr->row_number++;
+ if (png_ptr->row_number < png_ptr->num_rows)
+ return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ if (png_ptr->interlaced != 0)
+ {
+ png_ptr->row_number = 0;
+ memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+ do
+ {
+ png_ptr->pass++;
+ if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
+ (png_ptr->pass == 3 && png_ptr->width < 3) ||
+ (png_ptr->pass == 5 && png_ptr->width < 2))
+ png_ptr->pass++;
+
+ if (png_ptr->pass > 7)
+ png_ptr->pass--;
+
+ if (png_ptr->pass >= 7)
+ break;
+
+ png_ptr->iwidth = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+
+ if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+ break;
+
+ png_ptr->num_rows = (png_ptr->height +
+ png_pass_yinc[png_ptr->pass] - 1 -
+ png_pass_ystart[png_ptr->pass]) /
+ png_pass_yinc[png_ptr->pass];
+
+ } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
+ }
+#endif /* READ_INTERLACING */
+}
+
+void /* PRIVATE */
+png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+ if (png_ptr->info_fn != NULL)
+ (*(png_ptr->info_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+ if (png_ptr->end_fn != NULL)
+ (*(png_ptr->end_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_row(png_structrp png_ptr, png_bytep row)
+{
+ if (png_ptr->row_fn != NULL)
+ (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
+ (int)png_ptr->pass);
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void PNGAPI
+png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
+ png_const_bytep new_row)
+{
+ if (png_ptr == NULL)
+ return;
+
+ /* new_row is a flag here - if it is NULL then the app callback was called
+ * from an empty row (see the calls to png_struct::row_fn below), otherwise
+ * it must be png_ptr->row_buf+1
+ */
+ if (new_row != NULL)
+ png_combine_row(png_ptr, old_row, 1/*blocky display*/);
+}
+#endif /* READ_INTERLACING */
+
+void PNGAPI
+png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
+ png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+ png_progressive_end_ptr end_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->info_fn = info_fn;
+ png_ptr->row_fn = row_fn;
+ png_ptr->end_fn = end_fn;
+
+ png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
+}
+
+png_voidp PNGAPI
+png_get_progressive_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return (NULL);
+
+ return png_ptr->io_ptr;
+}
+#endif /* PROGRESSIVE_READ */
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