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[libpng17] Support builds with unsupported PNG_TRANSFORM_* values. All of the

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PNG_TRANSFORM_* values are always defined in png.h and, because they
are used for both read and write in some cases, it is not reliable
to #if out ones that are totally unsupported. This change adds error
detection in png_read_image() and png_write_image() to do a
png_app_error() if the app requests something that cannot be done
and it adds corresponding code to pngimage.c to handle such options
by not attempting to test them.
This commit is contained in:
John Bowler
2014-02-05 20:13:19 -06:00
committed by Glenn Randers-Pehrson
parent 3d7f3bbab7
commit fb1305faeb
5 changed files with 138 additions and 60 deletions
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76
pngwrite.c
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@@ -1532,81 +1532,117 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
if (png_ptr == NULL || info_ptr == NULL)
return;
if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
{
png_app_error(png_ptr, "no rows for png_write_image to write");
return;
}
/* Write the file header information. */
png_write_info(png_ptr, info_ptr);
/* ------ these transformations don't touch the info structure ------- */
#ifdef PNG_WRITE_INVERT_SUPPORTED
/* Invert monochrome pixels */
if (transforms & PNG_TRANSFORM_INVERT_MONO)
#ifdef PNG_WRITE_INVERT_SUPPORTED
png_set_invert_mono(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
#endif
#ifdef PNG_WRITE_SHIFT_SUPPORTED
/* Shift the pixels up to a legal bit depth and fill in
* as appropriate to correctly scale the image.
*/
if ((transforms & PNG_TRANSFORM_SHIFT)
&& (info_ptr->valid & PNG_INFO_sBIT))
png_set_shift(png_ptr, &info_ptr->sig_bit);
if (transforms & PNG_TRANSFORM_SHIFT)
#ifdef PNG_WRITE_SHIFT_SUPPORTED
if (info_ptr->valid & PNG_INFO_sBIT)
png_set_shift(png_ptr, &info_ptr->sig_bit);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
#endif
#ifdef PNG_WRITE_PACK_SUPPORTED
/* Pack pixels into bytes */
if (transforms & PNG_TRANSFORM_PACKING)
png_set_packing(png_ptr);
#ifdef PNG_WRITE_PACK_SUPPORTED
png_set_packing(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
#endif
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
/* Swap location of alpha bytes from ARGB to RGBA */
if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
png_set_swap_alpha(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
#endif
/* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
* RGB, note that the code expects the input color type to be G or RGB; no
* alpha channel.
*/
if (transforms &
(PNG_TRANSFORM_STRIP_FILLER_AFTER|PNG_TRANSFORM_STRIP_FILLER_BEFORE))
{
#ifdef PNG_WRITE_FILLER_SUPPORTED
/* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
{
if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
png_app_error(png_ptr,
"PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
/* Continue if ignored - this is the pre-1.6.10 behavior */
png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
}
else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
#endif
}
#ifdef PNG_WRITE_BGR_SUPPORTED
/* Flip BGR pixels to RGB */
if (transforms & PNG_TRANSFORM_BGR)
#ifdef PNG_WRITE_BGR_SUPPORTED
png_set_bgr(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
#endif
#ifdef PNG_WRITE_SWAP_SUPPORTED
/* Swap bytes of 16-bit files to most significant byte first */
if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
#ifdef PNG_WRITE_SWAP_SUPPORTED
png_set_swap(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
#endif
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
/* Swap bits of 1, 2, 4 bit packed pixel formats */
if (transforms & PNG_TRANSFORM_PACKSWAP)
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
png_set_packswap(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
#endif
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
/* Invert the alpha channel from opacity to transparency */
if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
png_set_invert_alpha(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
#endif
/* ----------------------- end of transformations ------------------- */
/* Write the bits */
if (info_ptr->valid & PNG_INFO_IDAT)
png_write_image(png_ptr, info_ptr->row_pointers);
png_write_image(png_ptr, info_ptr->row_pointers);
/* It is REQUIRED to call this to finish writing the rest of the file */
png_write_end(png_ptr, info_ptr);
PNG_UNUSED(transforms) /* Quiet compiler warnings */
PNG_UNUSED(params)
}
#endif