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https://git.code.sf.net/p/libpng/code.git
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[libpng17] Removed non-working progressive reader 'skip' function. This
function has apparently never been used. It was implemented to support back-door modification of png_struct in libpng-1.4.x but (because it does nothing and cannot do anything) was apparently never tested (John Bowler).
This commit is contained in:
John Bowler
Glenn Randers-Pehrson
parent
3d1fec50e8
commit
9307eef199
9
ANNOUNCE
9
ANNOUNCE
@ -1,5 +1,5 @@
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Libpng 1.7.0beta64 - June 6, 2015
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Libpng 1.7.0beta64 - June 7, 2015
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This is not intended to be a public release. It will be replaced
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within a few weeks by a public version or by another test version.
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@ -835,7 +835,12 @@ Version 1.7.0beta63 [June 6, 2015]
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to compile them without the minimum required support enabled
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(suggested by Flavio Medeiros).
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Version 1.7.0beta64 [June 6, 2015]
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Version 1.7.0beta64 [June 7, 2015]
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Removed non-working progressive reader 'skip' function. This
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function has apparently never been used. It was implemented
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to support back-door modification of png_struct in libpng-1.4.x
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but (because it does nothing and cannot do anything) was apparently
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never tested (John Bowler).
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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(subscription required; visit
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7
CHANGES
7
CHANGES
@ -5130,7 +5130,12 @@ Version 1.7.0beta63 [June 6, 2015]
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to compile them without the minimum required support enabled
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(suggested by Flavio Medeiros).
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Version 1.7.0beta64 [June 6, 2015]
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Version 1.7.0beta64 [June 7, 2015]
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Removed non-working progressive reader 'skip' function. This
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function has apparently never been used. It was implemented
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to support back-door modification of png_struct in libpng-1.4.x
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but (because it does nothing and cannot do anything) was apparently
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never tested (John Bowler).
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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(subscription required; visit
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104
pngpread.c
104
pngpread.c
@ -20,7 +20,6 @@
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#define PNG_READ_SIG_MODE 0
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#define PNG_READ_CHUNK_MODE 1
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#define PNG_READ_IDAT_MODE 2
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#define PNG_SKIP_MODE 3
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#define PNG_READ_tEXt_MODE 4
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#define PNG_READ_zTXt_MODE 5
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#define PNG_READ_DONE_MODE 6
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@ -79,32 +78,14 @@ png_process_data_pause(png_structrp png_ptr, int save)
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png_uint_32 PNGAPI
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png_process_data_skip(png_structrp png_ptr)
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{
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png_uint_32 remaining = 0;
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if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
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png_ptr->skip_length > 0)
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{
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/* At the end of png_process_data the buffer size must be 0 (see the loop
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* above) so we can detect a broken call here:
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*/
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if (png_ptr->buffer_size != 0)
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png_error(png_ptr,
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"png_process_data_skip called inside png_process_data");
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/* If is impossible for there to be a saved buffer at this point -
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* otherwise we could not be in SKIP mode. This will also happen if
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* png_process_skip is called inside png_process_data (but only very
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* rarely.)
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*/
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if (png_ptr->save_buffer_size != 0)
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png_error(png_ptr, "png_process_data_skip called with saved data");
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remaining = png_ptr->skip_length;
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png_ptr->skip_length = 0;
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png_ptr->process_mode = PNG_READ_CHUNK_MODE;
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}
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return remaining;
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/* TODO: somewhere the implementation of this seems to have been lost,
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* or abandoned. It was only to support some internal snooping done by
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* Mozilla (i.e. back-door access to png_struct) in 1.4; apparently they
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* must have stopped doing it.
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*/
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png_app_warning(png_ptr,
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"png_process_data_skip is not implemented in any current version of libpng");
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return 0;
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}
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/* What we do with the incoming data depends on what we were previously
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@ -136,12 +117,6 @@ png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
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break;
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}
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case PNG_SKIP_MODE:
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{
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png_push_crc_finish(png_ptr);
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break;
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}
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default:
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{
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png_ptr->buffer_size = 0;
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@ -439,69 +414,6 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
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png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
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}
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void /* PRIVATE */
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png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
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{
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png_ptr->process_mode = PNG_SKIP_MODE;
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png_ptr->skip_length = skip;
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}
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void /* PRIVATE */
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png_push_crc_finish(png_structrp png_ptr)
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{
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if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
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{
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png_size_t save_size = png_ptr->save_buffer_size;
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png_uint_32 skip_length = png_ptr->skip_length;
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/* We want the smaller of 'skip_length' and 'save_buffer_size', but
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* they are of different types and we don't know which variable has the
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* fewest bits. Carefully select the smaller and cast it to the type of
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* the larger - this cannot overflow. Do not cast in the following test
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* - it will break on either 16 or 64 bit platforms.
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*/
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if (skip_length < save_size)
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save_size = (png_size_t)skip_length;
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else
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skip_length = (png_uint_32)save_size;
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png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
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png_ptr->skip_length -= skip_length;
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png_ptr->buffer_size -= save_size;
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png_ptr->save_buffer_size -= save_size;
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png_ptr->save_buffer_ptr += save_size;
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}
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if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
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{
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png_size_t save_size = png_ptr->current_buffer_size;
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png_uint_32 skip_length = png_ptr->skip_length;
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/* We want the smaller of 'skip_length' and 'current_buffer_size', here,
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* the same problem exists as above and the same solution.
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*/
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if (skip_length < save_size)
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save_size = (png_size_t)skip_length;
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else
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skip_length = (png_uint_32)save_size;
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png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
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png_ptr->skip_length -= skip_length;
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png_ptr->buffer_size -= save_size;
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png_ptr->current_buffer_size -= save_size;
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png_ptr->current_buffer_ptr += save_size;
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}
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if (png_ptr->skip_length == 0)
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{
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PNG_PUSH_SAVE_BUFFER_IF_LT(4)
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png_crc_finish(png_ptr, 0);
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png_ptr->process_mode = PNG_READ_CHUNK_MODE;
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}
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}
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void PNGCBAPI
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png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
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{
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@ -1634,10 +1634,6 @@ PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
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PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
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png_inforp info_ptr),PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
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png_uint_32 length),PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
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PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
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PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
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