mirror of
https://git.code.sf.net/p/libpng/code.git
synced 2025-07-10 18:04:09 +02:00
[libpng16] Start-up code size improvements, error handler flexibility.
These changes alter how the tricky allocation of the initial png_struct and png_info structures are handled. png_info is now handled in pretty much the same way as everything else, except that the allocations handle NULL return silently. png_struct is changed in a similar way on allocation and on deallocation a 'safety' error handler is put in place (which should never be required). The error handler itself is changed to permit mismatches in the application and libpng error buffer size; however, this means a silent change to the API to return the jmp_buf if the size doesn't match the size from the libpng compilation; libpng now allocates the memory and this may fail. Overall these changes result in slight code size reductions; however, this is a reduction in code that is always executed so is particularly valuable. Overall on a 64-bit system the libpng DLL decreases in code size by 1733 bytes. pngerror.o increases in size by about 465 bytes because of the new functionality.
This commit is contained in:
John Bowler
committed by
Glenn Randers-Pehrson
Glenn Randers-Pehrson
parent
b74fb4e49c
commit
d332c67da7
222
pngwrite.c
222
pngwrite.c
@@ -449,92 +449,34 @@ PNG_FUNCTION(png_structp,PNGAPI
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png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
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png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
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{
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#ifdef PNG_USER_MEM_SUPPORTED
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return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
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warn_fn, NULL, NULL, NULL));
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#ifndef PNG_USER_MEM_SUPPORTED
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png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
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error_fn, warn_fn, NULL, NULL, NULL);
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#else
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return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
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warn_fn, NULL, NULL, NULL);
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}
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/* Alternate initialize png_ptr structure, and allocate any memory needed */
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static void png_reset_filter_heuristics(png_structp png_ptr); /* forward decl */
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PNG_FUNCTION(png_structp,PNGAPI
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png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
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png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
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png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
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{
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png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
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error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
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#endif /* PNG_USER_MEM_SUPPORTED */
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volatile int png_cleanup_needed = 0;
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#ifdef PNG_SETJMP_SUPPORTED
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volatile
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#endif
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png_structp png_ptr;
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png_debug(1, "in png_create_write_struct");
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#ifdef PNG_USER_MEM_SUPPORTED
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png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
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(png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
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#else
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png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
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#endif /* PNG_USER_MEM_SUPPORTED */
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if (png_ptr == NULL)
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return (NULL);
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/* Added at libpng-1.2.6 */
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#ifdef PNG_SET_USER_LIMITS_SUPPORTED
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png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
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png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
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#endif
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#ifdef PNG_SETJMP_SUPPORTED
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/* Applications that neglect to set up their own setjmp() and then
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* encounter a png_error() will longjmp here. Since the jmpbuf is
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* then meaningless we abort instead of returning.
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*/
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if (setjmp(png_jmpbuf(png_ptr))) /* sets longjmp to match setjmp */
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PNG_ABORT();
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#endif
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#ifdef PNG_USER_MEM_SUPPORTED
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png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
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#endif /* PNG_USER_MEM_SUPPORTED */
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png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
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if (!png_user_version_check(png_ptr, user_png_ver))
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png_cleanup_needed = 1;
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/* Initialize zbuf - compression buffer */
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png_ptr->zbuf_size = PNG_ZBUF_SIZE;
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if (!png_cleanup_needed)
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if (png_ptr != NULL)
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{
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png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr,
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png_ptr->zbuf_size);
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if (png_ptr->zbuf == NULL)
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png_cleanup_needed = 1;
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/* TODO: delay this, it can be done in png_init_io() (if the app doesn't
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* do it itself) avoiding setting the default function if it is not
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* required.
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*/
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png_set_write_fn(png_ptr, NULL, NULL, NULL);
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}
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if (png_cleanup_needed)
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{
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/* Clean up PNG structure and deallocate any memory. */
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png_free(png_ptr, png_ptr->zbuf);
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png_ptr->zbuf = NULL;
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#ifdef PNG_USER_MEM_SUPPORTED
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png_destroy_struct_2((png_voidp)png_ptr,
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(png_free_ptr)free_fn, (png_voidp)mem_ptr);
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#else
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png_destroy_struct((png_voidp)png_ptr);
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#endif
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return (NULL);
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}
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png_set_write_fn(png_ptr, NULL, NULL, NULL);
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#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
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png_reset_filter_heuristics(png_ptr);
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#endif
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return (png_ptr);
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return png_ptr;
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}
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@@ -862,87 +804,14 @@ png_write_flush(png_structp png_ptr)
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}
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#endif /* PNG_WRITE_FLUSH_SUPPORTED */
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/* Free all memory used by the write */
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void PNGAPI
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png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
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{
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png_structp png_ptr = NULL;
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png_infop info_ptr = NULL;
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#ifdef PNG_USER_MEM_SUPPORTED
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png_free_ptr free_fn = NULL;
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png_voidp mem_ptr = NULL;
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#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
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static void png_reset_filter_heuristics(png_structp png_ptr); /* forward decl */
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#endif
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png_debug(1, "in png_destroy_write_struct");
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if (png_ptr_ptr != NULL)
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png_ptr = *png_ptr_ptr;
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#ifdef PNG_USER_MEM_SUPPORTED
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if (png_ptr != NULL)
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{
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free_fn = png_ptr->free_fn;
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mem_ptr = png_ptr->mem_ptr;
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}
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#endif
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if (info_ptr_ptr != NULL)
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info_ptr = *info_ptr_ptr;
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if (info_ptr != NULL)
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{
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if (png_ptr != NULL)
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{
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png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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if (png_ptr->num_chunk_list)
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{
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png_free(png_ptr, png_ptr->chunk_list);
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png_ptr->num_chunk_list = 0;
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}
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#endif
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}
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#ifdef PNG_USER_MEM_SUPPORTED
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png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
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(png_voidp)mem_ptr);
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#else
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png_destroy_struct((png_voidp)info_ptr);
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#endif
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*info_ptr_ptr = NULL;
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}
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if (png_ptr != NULL)
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{
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png_write_destroy(png_ptr);
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#ifdef PNG_USER_MEM_SUPPORTED
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png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
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(png_voidp)mem_ptr);
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#else
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png_destroy_struct((png_voidp)png_ptr);
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#endif
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*png_ptr_ptr = NULL;
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}
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}
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/* Free any memory used in png_ptr struct (old method) */
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void /* PRIVATE */
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/* Free any memory used in png_ptr struct without freeing the struct itself. */
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static void
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png_write_destroy(png_structp png_ptr)
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{
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#ifdef PNG_SETJMP_SUPPORTED
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jmp_buf tmp_jmp; /* Save jump buffer */
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#endif
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png_error_ptr error_fn;
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#ifdef PNG_WARNINGS_SUPPORTED
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png_error_ptr warning_fn;
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#endif
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png_voidp error_ptr;
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#ifdef PNG_USER_MEM_SUPPORTED
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png_free_ptr free_fn;
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#endif
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png_debug(1, "in png_write_destroy");
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/* Free any memory zlib uses */
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@@ -967,34 +836,41 @@ png_write_destroy(png_structp png_ptr)
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png_free(png_ptr, png_ptr->inv_filter_costs);
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#endif
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#ifdef PNG_SETJMP_SUPPORTED
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/* Reset structure */
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png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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png_free(png_ptr, png_ptr->chunk_list);
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#endif
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error_fn = png_ptr->error_fn;
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#ifdef PNG_WARNINGS_SUPPORTED
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warning_fn = png_ptr->warning_fn;
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#endif
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error_ptr = png_ptr->error_ptr;
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#ifdef PNG_USER_MEM_SUPPORTED
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free_fn = png_ptr->free_fn;
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#endif
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/* The error handling and memory handling information is left intact at this
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* point: the jmp_buf may still have to be freed. See png_destroy_png_struct
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* for how this happens.
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*/
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}
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png_memset(png_ptr, 0, png_sizeof(png_struct));
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/* Free all memory used by the write.
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* In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
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* *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
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* the passed in info_structs but it would quietly fail to free any of the data
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* inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
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* has no png_ptr.)
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*/
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void PNGAPI
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png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
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{
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png_debug(1, "in png_destroy_write_struct");
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png_ptr->error_fn = error_fn;
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#ifdef PNG_WARNINGS_SUPPORTED
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png_ptr->warning_fn = warning_fn;
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#endif
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png_ptr->error_ptr = error_ptr;
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#ifdef PNG_USER_MEM_SUPPORTED
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png_ptr->free_fn = free_fn;
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#endif
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if (png_ptr_ptr != NULL)
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{
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png_structp png_ptr = *png_ptr_ptr;
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#ifdef PNG_SETJMP_SUPPORTED
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png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
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#endif
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if (png_ptr != NULL) /* added in libpng 1.6.0 */
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{
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png_destroy_info_struct(png_ptr, info_ptr_ptr);
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*png_ptr_ptr = NULL;
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png_write_destroy(png_ptr);
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png_destroy_png_struct(png_ptr);
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}
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}
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}
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/* Allow the application to select one or more row filters to use. */
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