Updates the PNG library to 1.2.37, enables some functionality for O3D

third_party/libpng/pngread.c

 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.2.35 [February 14, 2009]
+ * Last changed in libpng 1.2.37 [June 4, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 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 file contains routines that an application calls directly to
  * read a PNG file or stream.
  */
 
 #define PNG_INTERNAL
@@ skipping 35 matching lines @@
    png_debug(1, "in png_create_read_struct");
 #ifdef PNG_USER_MEM_SUPPORTED
    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
       (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
 #else
    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
 #endif
    if (png_ptr == NULL)
       return (NULL);
 
-   /* added at libpng-1.2.6 */
+   /* Added at libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
 #ifdef USE_FAR_KEYWORD
    if (setjmp(jmpbuf))
 #else
    if (setjmp(png_ptr->jmpbuf))
@@ skipping 59 matching lines @@
         png_warning(png_ptr, msg);
 #endif
 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
         png_ptr->flags = 0;
 #endif
         png_error(png_ptr,
            "Incompatible libpng version in application and library");
      }
    }
 
-   /* initialize zbuf - compression buffer */
+   /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
      (png_uint_32)png_ptr->zbuf_size);
    png_ptr->zstream.zalloc = png_zalloc;
    png_ptr->zstream.zfree = png_zfree;
    png_ptr->zstream.opaque = (voidpf)png_ptr;
 
    switch (inflateInit(&png_ptr->zstream))
    {
      case Z_OK: /* Do nothing */ break;
@@ skipping 34 matching lines @@
 {
    /* We only come here via pre-1.0.7-compiled applications */
    png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
 }
 
 void PNGAPI
 png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
    png_size_t png_struct_size, png_size_t png_info_size)
 {
    /* We only come here via pre-1.0.12-compiled applications */
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
    if (png_sizeof(png_struct) > png_struct_size ||
       png_sizeof(png_info) > png_info_size)
    {
       char msg[80];
       png_ptr->warning_fn = NULL;
       if (user_png_ver)
       {
         png_snprintf(msg, 80,
            "Application was compiled with png.h from libpng-%.20s",
@@ skipping 33 matching lines @@
    png_size_t png_struct_size)
 {
 #ifdef PNG_SETJMP_SUPPORTED
    jmp_buf tmp_jmp;  /* to save current jump buffer */
 #endif
 
    int i = 0;
 
    png_structp png_ptr=*ptr_ptr;
 
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 
    do
    {
      if (user_png_ver[i] != png_libpng_ver[i])
      {
 #ifdef PNG_LEGACY_SUPPORTED
        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 #else
        png_ptr->warning_fn = NULL;
        png_warning(png_ptr,
         "Application uses deprecated png_read_init() and should be recompiled.");
        break;
 #endif
      }
    } while (png_libpng_ver[i++]);
 
    png_debug(1, "in png_read_init_3");
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* save jump buffer and error functions */
+   /* Save jump buffer and error functions */
    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
 #endif
 
    if (png_sizeof(png_struct) > png_struct_size)
    {
       png_destroy_struct(png_ptr);
       *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
       png_ptr = *ptr_ptr;
    }
 
-   /* reset all variables to 0 */
+   /* Reset all variables to 0 */
    png_memset(png_ptr, 0, png_sizeof(png_struct));
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* restore jump buffer */
+   /* Restore jump buffer */
    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
 #endif
 
-   /* added at libpng-1.2.6 */
+   /* Added at libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 #endif
 
-   /* initialize zbuf - compression buffer */
+   /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
      (png_uint_32)png_ptr->zbuf_size);
    png_ptr->zstream.zalloc = png_zalloc;
    png_ptr->zstream.zfree = png_zfree;
    png_ptr->zstream.opaque = (voidpf)png_ptr;
 
    switch (inflateInit(&png_ptr->zstream))
    {
      case Z_OK: /* Do nothing */ break;
@@ skipping 14 matching lines @@
  * changed in v0.90 to allow reading a file that already has the magic
  * bytes read from the stream.  You can tell libpng how many bytes have
  * been read from the beginning of the stream (up to the maximum of 8)
  * via png_set_sig_bytes(), and we will only check the remaining bytes
  * here.  The application can then have access to the signature bytes we
  * read if it is determined that this isn't a valid PNG file.
  */
 void PNGAPI
 png_read_info(png_structp png_ptr, png_infop info_ptr)
 {
-   if (png_ptr == NULL || info_ptr == NULL) return;
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
    png_debug(1, "in png_read_info");
    /* If we haven't checked all of the PNG signature bytes, do so now. */
    if (png_ptr->sig_bytes < 8)
    {
       png_size_t num_checked = png_ptr->sig_bytes,
                  num_to_check = 8 - num_checked;
 
       png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
       png_ptr->sig_bytes = 8;
 
@@ skipping 182 matching lines @@
 #if defined(PNG_READ_iTXt_SUPPORTED)
       else if (!png_memcmp(chunk_name, png_iTXt, 4))
          png_handle_iTXt(png_ptr, info_ptr, length);
 #endif
       else
          png_handle_unknown(png_ptr, info_ptr, length);
    }
 }
 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 
-/* optional call to update the users info_ptr structure */
+/* Optional call to update the users info_ptr structure */
 void PNGAPI
 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_update_info");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
    else
       png_warning(png_ptr,
       "Ignoring extra png_read_update_info() call; row buffer not reallocated");
    png_read_transform_info(png_ptr, info_ptr);
 }
 
 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 /* Initialize palette, background, etc, after transformations
  * are set, but before any reading takes place.  This allows
  * the user to obtain a gamma-corrected palette, for example.
  * If the user doesn't call this, we will do it ourselves.
  */
 void PNGAPI
 png_start_read_image(png_structp png_ptr)
 {
    png_debug(1, "in png_start_read_image");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
 }
 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 
 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 void PNGAPI
 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 {
 #ifdef PNG_USE_LOCAL_ARRAYS
    PNG_CONST PNG_IDAT;
    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
       0xff};
    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 #endif
    int ret;
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_debug2(1, "in png_read_row (row %lu, pass %d)",
       png_ptr->row_number, png_ptr->pass);
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
    {
-   /* check for transforms that have been set but were defined out */
+   /* Check for transforms that have been set but were defined out */
 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
    if (png_ptr->transformations & PNG_INVERT_MONO)
       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
 #endif
 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
    if (png_ptr->transformations & PNG_FILLER)
       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
 #endif
 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
    if (png_ptr->transformations & PNG_PACKSWAP)
@@ skipping 11 matching lines @@
    if (png_ptr->transformations & PNG_BGR)
       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
 #endif
 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
    if (png_ptr->transformations & PNG_SWAP_BYTES)
       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
 #endif
    }
 
 #if defined(PNG_READ_INTERLACING_SUPPORTED)
-   /* if interlaced and we do not need a new row, combine row and return */
+   /* If interlaced and we do not need a new row, combine row and return */
    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
    {
       switch (png_ptr->pass)
       {
          case 0:
             if (png_ptr->row_number & 0x07)
             {
                if (dsp_row != NULL)
                   png_combine_row(png_ptr, dsp_row,
                      png_pass_dsp_mask[png_ptr->pass]);
@@ skipping 126 matching lines @@
       /* Intrapixel differencing */
       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
    }
 #endif
 
 
    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
       png_do_read_transformations(png_ptr);
 
 #if defined(PNG_READ_INTERLACING_SUPPORTED)
-   /* blow up interlaced rows to full size */
+   /* Blow up interlaced rows to full size */
    if (png_ptr->interlaced &&
       (png_ptr->transformations & PNG_INTERLACE))
    {
       if (png_ptr->pass < 6)
-/*       old interface (pre-1.0.9):
-         png_do_read_interlace(&(png_ptr->row_info),
-            png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
- */
+         /* Old interface (pre-1.0.9):
+          * png_do_read_interlace(&(png_ptr->row_info),
+          *    png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
+          */
          png_do_read_interlace(png_ptr);
 
       if (dsp_row != NULL)
          png_combine_row(png_ptr, dsp_row,
             png_pass_dsp_mask[png_ptr->pass]);
       if (row != NULL)
          png_combine_row(png_ptr, row,
             png_pass_mask[png_ptr->pass]);
    }
    else
@@ skipping 38 matching lines @@
 
 void PNGAPI
 png_read_rows(png_structp png_ptr, png_bytepp row,
    png_bytepp display_row, png_uint_32 num_rows)
 {
    png_uint_32 i;
    png_bytepp rp;
    png_bytepp dp;
 
    png_debug(1, "in png_read_rows");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    rp = row;
    dp = display_row;
    if (rp != NULL && dp != NULL)
       for (i = 0; i < num_rows; i++)
       {
          png_bytep rptr = *rp++;
          png_bytep dptr = *dp++;
 
          png_read_row(png_ptr, rptr, dptr);
       }
@@ skipping 28 matching lines @@
  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
  */
 void PNGAPI
 png_read_image(png_structp png_ptr, png_bytepp image)
 {
    png_uint_32 i, image_height;
    int pass, j;
    png_bytepp rp;
 
    png_debug(1, "in png_read_image");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    pass = png_set_interlace_handling(png_ptr);
 #else
    if (png_ptr->interlaced)
       png_error(png_ptr,
         "Cannot read interlaced image -- interlace handler disabled.");
    pass = 1;
 #endif
 
@@ skipping 15 matching lines @@
 
 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 /* Read the end of the PNG file.  Will not read past the end of the
  * file, will verify the end is accurate, and will read any comments
  * or time information at the end of the file, if info is not NULL.
  */
 void PNGAPI
 png_read_end(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_end");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 
    do
    {
 #ifdef PNG_USE_LOCAL_ARRAYS
       PNG_CONST PNG_IHDR;
       PNG_CONST PNG_IDAT;
       PNG_CONST PNG_IEND;
       PNG_CONST PNG_PLTE;
 #if defined(PNG_READ_bKGD_SUPPORTED)
@@ skipping 146 matching lines @@
 #if defined(PNG_READ_iTXt_SUPPORTED)
       else if (!png_memcmp(chunk_name, png_iTXt, 4))
          png_handle_iTXt(png_ptr, info_ptr, length);
 #endif
       else
          png_handle_unknown(png_ptr, info_ptr, length);
    } while (!(png_ptr->mode & PNG_HAVE_IEND));
 }
 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 
-/* free all memory used by the read */
+/* Free all memory used by the read */
 void PNGAPI
 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
    png_infopp end_info_ptr_ptr)
 {
    png_structp png_ptr = NULL;
    png_infop info_ptr = NULL, end_info_ptr = NULL;
 #ifdef PNG_USER_MEM_SUPPORTED
    png_free_ptr free_fn = NULL;
    png_voidp mem_ptr = NULL;
 #endif
@@ skipping 51 matching lines @@
 #ifdef PNG_USER_MEM_SUPPORTED
       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
           (png_voidp)mem_ptr);
 #else
       png_destroy_struct((png_voidp)png_ptr);
 #endif
       *png_ptr_ptr = NULL;
    }
 }
 
-/* free all memory used by the read (old method) */
+/* Free all memory used by the read (old method) */
 void /* PRIVATE */
 png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
 {
 #ifdef PNG_SETJMP_SUPPORTED
    jmp_buf tmp_jmp;
 #endif
    png_error_ptr error_fn;
    png_error_ptr warning_fn;
    png_voidp error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
@@ skipping 128 matching lines @@
 
 #ifdef PNG_SETJMP_SUPPORTED
    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
 #endif
 
 }
 
 void PNGAPI
 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->read_row_fn = read_row_fn;
 }
 
 
 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 #if defined(PNG_INFO_IMAGE_SUPPORTED)
 void PNGAPI
 png_read_png(png_structp png_ptr, png_infop info_ptr,
                            int transforms,
                            voidp params)
 {
    int row;
 
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
-   /* invert the alpha channel from opacity to transparency
+   /* Invert the alpha channel from opacity to transparency
     */
    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
        png_set_invert_alpha(png_ptr);
 #endif
 
    /* png_read_info() gives us all of the information from the
     * PNG file before the first IDAT (image data chunk).
     */
    png_read_info(png_ptr, info_ptr);
    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
       png_error(png_ptr, "Image is too high to process with png_read_png()");
 
    /* -------------- image transformations start here ------------------- */
 
 #if defined(PNG_READ_16_TO_8_SUPPORTED)
-   /* tell libpng to strip 16 bit/color files down to 8 bits per color
+   /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
     */
    if (transforms & PNG_TRANSFORM_STRIP_16)
-       png_set_strip_16(png_ptr);
+      png_set_strip_16(png_ptr);
 #endif
 
 #if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
    /* Strip alpha bytes from the input data without combining with
     * the background (not recommended).
     */
    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
-       png_set_strip_alpha(png_ptr);
+      png_set_strip_alpha(png_ptr);
 #endif
 
 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
     * byte into separate bytes (useful for paletted and grayscale images).
     */
    if (transforms & PNG_TRANSFORM_PACKING)
-       png_set_packing(png_ptr);
+      png_set_packing(png_ptr);
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)
    /* Change the order of packed pixels to least significant bit first
     * (not useful if you are using png_set_packing).
     */
    if (transforms & PNG_TRANSFORM_PACKSWAP)
-       png_set_packswap(png_ptr);
+      png_set_packswap(png_ptr);
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED)
    /* Expand paletted colors into true RGB triplets
     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
     * Expand paletted or RGB images with transparency to full alpha
     * channels so the data will be available as RGBA quartets.
     */
    if (transforms & PNG_TRANSFORM_EXPAND)
-       if ((png_ptr->bit_depth < 8) ||
-           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
-           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
+      if ((png_ptr->bit_depth < 8) ||
+          (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
+          (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
          png_set_expand(png_ptr);
 #endif
 
    /* We don't handle background color or gamma transformation or dithering.
     */
 
 #if defined(PNG_READ_INVERT_SUPPORTED)
-   /* invert monochrome files to have 0 as white and 1 as black
+   /* Invert monochrome files to have 0 as white and 1 as black
     */
    if (transforms & PNG_TRANSFORM_INVERT_MONO)
-       png_set_invert_mono(png_ptr);
+      png_set_invert_mono(png_ptr);
 #endif
 
 #if defined(PNG_READ_SHIFT_SUPPORTED)
    /* If you want to shift the pixel values from the range [0,255] or
     * [0,65535] to the original [0,7] or [0,31], or whatever range the
     * colors were originally in:
     */
    if ((transforms & PNG_TRANSFORM_SHIFT)
        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
    {
       png_color_8p sig_bit;
 
       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
       png_set_shift(png_ptr, sig_bit);
    }
 #endif
 
 #if defined(PNG_READ_BGR_SUPPORTED)
-   /* flip the RGB pixels to BGR (or RGBA to BGRA)
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA)
     */
    if (transforms & PNG_TRANSFORM_BGR)
-       png_set_bgr(png_ptr);
+      png_set_bgr(png_ptr);
 #endif
 
 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
-   /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
     */
    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
        png_set_swap_alpha(png_ptr);
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED)
-   /* swap bytes of 16 bit files to least significant byte first
+   /* Swap bytes of 16 bit files to least significant byte first
     */
    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
-       png_set_swap(png_ptr);
+      png_set_swap(png_ptr);
 #endif
 
    /* We don't handle adding filler bytes */
 
    /* Optional call to gamma correct and add the background to the palette
     * and update info structure.  REQUIRED if you are expecting libpng to
     * update the palette for you (i.e., you selected such a transform above).
     */
    png_read_update_info(png_ptr, info_ptr);
 
@@ skipping 12 matching lines @@
       info_ptr->free_me |= PNG_FREE_ROWS;
 #endif
       for (row = 0; row < (int)info_ptr->height; row++)
          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
             png_get_rowbytes(png_ptr, info_ptr));
    }
 
    png_read_image(png_ptr, info_ptr->row_pointers);
    info_ptr->valid |= PNG_INFO_IDAT;
 
-   /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
+   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);
 
-   transforms = transforms; /* quiet compiler warnings */
+   transforms = transforms; /* Quiet compiler warnings */
    params = params;
 
 }
 #endif /* PNG_INFO_IMAGE_SUPPORTED */
 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 #endif /* PNG_READ_SUPPORTED */