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[libpng16] Allow fine grain control of unknown chunk APIs. This change allows

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png_set_keep_unknown_chunks() to be turned off if not required and causes
both read and write to behave appropriately (on read this is only possible
if the user callback is used to handle unknown chunks).  The change
also removes the support for storing unknown chunks in the info_struct
if the only unknown handling enabled is via the callback, allowing libpng
to be configured with callback reading and none of the unnecessary code.
This commit is contained in:
John Bowler
2012-08-16 16:12:13 -05:00
committed by Glenn Randers-Pehrson
parent 025d415838
commit 4a6c6df6c7
7 changed files with 74 additions and 20 deletions
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16
pngtest.c
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@@ -567,12 +567,14 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
/* Demonstration of user chunk support of the sTER and vpAg chunks */
#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
/* (sTER is a public chunk not yet known by libpng. vpAg is a private
chunk used in ImageMagick to store "virtual page" size). */
static png_uint_32 user_chunk_data[4];
/* The initializer must match the values actually stored in pngtest.png so that
* pngtest will pass if we don't have read callback support.
*/
static png_uint_32 user_chunk_data[4] = {2, 'd', 'd', 0};
/* 0: sTER mode + 1
* 1: vpAg width
@@ -580,6 +582,7 @@ static png_uint_32 user_chunk_data[4];
* 3: vpAg units
*/
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
static int PNGCBAPI read_user_chunk_callback(png_struct *png_ptr,
png_unknown_chunkp chunk)
{
@@ -726,7 +729,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
pngtest_warning);
#endif
#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
user_chunk_data[0] = 0;
user_chunk_data[1] = 0;
user_chunk_data[2] = 0;
@@ -862,6 +865,9 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
png_set_write_user_transform_fn(write_ptr, count_zero_samples);
#endif
#if 0 /* the following code is pointless, it doesn't work unless
PNG_READ_USER_CHUNKS_SUPPORTED, in which case it does nothing. */
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
# ifndef PNG_HANDLE_CHUNK_ALWAYS
# define PNG_HANDLE_CHUNK_ALWAYS 3
@@ -875,6 +881,8 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
# endif
png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_IF_SAFE,
NULL, 0);
#endif
#endif
#endif
pngtest_debug("Reading info struct");
@@ -1163,7 +1171,6 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
*/
png_write_info(write_ptr, write_info_ptr);
#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
if (user_chunk_data[0] != 0)
{
png_byte png_sTER[5] = {115, 84, 69, 82, '\0'};
@@ -1199,7 +1206,6 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
}
#endif
#endif
#ifdef SINGLE_ROWBUF_ALLOC
pngtest_debug("Allocating row buffer...");