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[libpng16] Reverted the fix of byte order in png_do_read_filler() with 16-bit

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input that was made in version 1.6.17beta01, to preserve legacy
behavior even though it was incorrect.  Instead, added new API
png_set_filter_16() and png_set_add_alpha_16() that set a flag to
make png_do_read_filter() interpret the filler bytes properly.
This commit is contained in:
Glenn Randers-Pehrson
2015-09-23 22:08:04 -05:00
parent d6eb4b71ac
commit efe4e5d10d
13 changed files with 141 additions and 65 deletions
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26
pngtrans.c
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@@ -119,7 +119,17 @@ png_set_interlace_handling(png_structrp png_ptr)
void PNGAPI
png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
{
png_debug(1, "in png_set_filler");
if (png_ptr == NULL)
return;
png_set_filler_16(png_ptr, filler, filler_loc);
png_ptr->flags &= ~PNG_FLAG_FILLER_16; /* Wrong byte order */
}
/* Added to libpng-1.5.24 */
void PNGAPI
png_set_filler_16(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
{
png_debug(1, "in png_set_filler_16");
if (png_ptr == NULL)
return;
@@ -139,6 +149,7 @@ png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
* confusion in the past.) The filler is only used in the read code.
*/
png_ptr->filler = (png_uint_16)filler;
png_ptr->flags |= PNG_FLAG_FILLER_16; /* Correct byte order */
# else
png_app_error(png_ptr, "png_set_filler not supported on read");
PNG_UNUSED(filler) /* not used in the write case */
@@ -202,13 +213,24 @@ png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
/* Added to libpng-1.2.7 */
void PNGAPI
png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
{
if (png_ptr == NULL)
return;
png_set_add_alpha_16(png_ptr, filler, filler_loc);
png_ptr->flags &= ~PNG_FLAG_FILLER_16; /* Wrong byte order */
}
/* Added to libpng-1.5.24 */
void PNGAPI
png_set_add_alpha_16(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
{
png_debug(1, "in png_set_add_alpha");
if (png_ptr == NULL)
return;
png_set_filler(png_ptr, filler, filler_loc);
png_set_filler_16(png_ptr, filler, filler_loc);
/* The above may fail to do anything. */
if ((png_ptr->transformations & PNG_FILLER) != 0)
png_ptr->transformations |= PNG_ADD_ALPHA;