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1306 lines
38 KiB
C
1306 lines
38 KiB
C
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/* pngread.c - read a PNG file
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*
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* Last changed in libpng 1.5.10 [March 8, 2012]
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* Copyright (c) 1998-2012 Glenn Randers-Pehrson
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* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
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* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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*
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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*
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* This file contains routines that an application calls directly to
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* read a PNG file or stream.
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*/
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#include "pngpriv.h"
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#ifdef PNG_READ_SUPPORTED
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/* Create a PNG structure for reading, and allocate any memory needed. */
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PNG_FUNCTION(png_structp,PNGAPI
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png_create_read_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_read_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 create PNG structure for reading, and allocate any memory
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* needed.
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*/
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PNG_FUNCTION(png_structp,PNGAPI
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png_create_read_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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#endif /* PNG_USER_MEM_SUPPORTED */
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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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volatile int png_cleanup_needed = 0;
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#ifdef PNG_SETJMP_SUPPORTED
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#ifdef USE_FAR_KEYWORD
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jmp_buf tmp_jmpbuf;
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#endif
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#endif
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png_debug(1, "in png_create_read_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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malloc_fn, 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
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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_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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/* Added at libpng-1.2.43 and 1.4.0 */
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png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
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/* Added at libpng-1.2.43 and 1.4.1 */
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png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_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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#ifdef USE_FAR_KEYWORD
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if (setjmp(tmp_jmpbuf))
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#else
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if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
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#endif
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PNG_ABORT();
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#ifdef USE_FAR_KEYWORD
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png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
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#endif
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#endif /* PNG_SETJMP_SUPPORTED */
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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
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png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
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/* Call the general version checker (shared with read and write code): */
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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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if (!png_cleanup_needed)
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{
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/* Initialize zbuf - compression buffer */
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png_ptr->zbuf_size = PNG_ZBUF_SIZE;
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png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr, 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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}
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png_ptr->zstream.zalloc = png_zalloc;
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png_ptr->zstream.zfree = png_zfree;
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png_ptr->zstream.opaque = (voidpf)png_ptr;
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if (!png_cleanup_needed)
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{
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switch (inflateInit(&png_ptr->zstream))
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{
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case Z_OK:
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break; /* Do nothing */
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case Z_MEM_ERROR:
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png_warning(png_ptr, "zlib memory error");
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png_cleanup_needed = 1;
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break;
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case Z_STREAM_ERROR:
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png_warning(png_ptr, "zlib stream error");
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png_cleanup_needed = 1;
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break;
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case Z_VERSION_ERROR:
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png_warning(png_ptr, "zlib version error");
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png_cleanup_needed = 1;
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break;
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default: png_warning(png_ptr, "Unknown zlib error");
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png_cleanup_needed = 1;
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}
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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_ptr->zstream.next_out = png_ptr->zbuf;
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png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
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png_set_read_fn(png_ptr, NULL, NULL);
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return (png_ptr);
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}
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#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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/* Read the information before the actual image data. This has been
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* changed in v0.90 to allow reading a file that already has the magic
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* bytes read from the stream. You can tell libpng how many bytes have
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* been read from the beginning of the stream (up to the maximum of 8)
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* via png_set_sig_bytes(), and we will only check the remaining bytes
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* here. The application can then have access to the signature bytes we
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* read if it is determined that this isn't a valid PNG file.
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*/
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void PNGAPI
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png_read_info(png_structp png_ptr, png_infop info_ptr)
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{
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png_debug(1, "in png_read_info");
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if (png_ptr == NULL || info_ptr == NULL)
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return;
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/* Read and check the PNG file signature. */
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png_read_sig(png_ptr, info_ptr);
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for (;;)
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{
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png_uint_32 length = png_read_chunk_header(png_ptr);
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png_uint_32 chunk_name = png_ptr->chunk_name;
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/* This should be a binary subdivision search or a hash for
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* matching the chunk name rather than a linear search.
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*/
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if (chunk_name == png_IDAT)
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if (png_ptr->mode & PNG_AFTER_IDAT)
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png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
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if (chunk_name == png_IHDR)
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png_handle_IHDR(png_ptr, info_ptr, length);
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else if (chunk_name == png_IEND)
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png_handle_IEND(png_ptr, info_ptr, length);
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
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PNG_HANDLE_CHUNK_AS_DEFAULT)
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{
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if (chunk_name == png_IDAT)
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png_ptr->mode |= PNG_HAVE_IDAT;
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png_handle_unknown(png_ptr, info_ptr, length);
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if (chunk_name == png_PLTE)
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png_ptr->mode |= PNG_HAVE_PLTE;
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else if (chunk_name == png_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_error(png_ptr, "Missing PLTE before IDAT");
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break;
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}
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}
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#endif
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else if (chunk_name == png_PLTE)
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png_handle_PLTE(png_ptr, info_ptr, length);
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else if (chunk_name == png_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_error(png_ptr, "Missing PLTE before IDAT");
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png_ptr->idat_size = length;
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png_ptr->mode |= PNG_HAVE_IDAT;
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break;
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}
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#ifdef PNG_READ_bKGD_SUPPORTED
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else if (chunk_name == png_bKGD)
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png_handle_bKGD(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_cHRM_SUPPORTED
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else if (chunk_name == png_cHRM)
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png_handle_cHRM(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_gAMA_SUPPORTED
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else if (chunk_name == png_gAMA)
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png_handle_gAMA(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_hIST_SUPPORTED
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else if (chunk_name == png_hIST)
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png_handle_hIST(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_oFFs_SUPPORTED
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else if (chunk_name == png_oFFs)
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png_handle_oFFs(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_pCAL_SUPPORTED
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else if (chunk_name == png_pCAL)
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png_handle_pCAL(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_sCAL_SUPPORTED
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else if (chunk_name == png_sCAL)
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png_handle_sCAL(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_pHYs_SUPPORTED
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else if (chunk_name == png_pHYs)
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png_handle_pHYs(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_sBIT_SUPPORTED
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else if (chunk_name == png_sBIT)
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png_handle_sBIT(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_sRGB_SUPPORTED
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else if (chunk_name == png_sRGB)
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png_handle_sRGB(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_iCCP_SUPPORTED
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else if (chunk_name == png_iCCP)
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png_handle_iCCP(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_sPLT_SUPPORTED
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else if (chunk_name == png_sPLT)
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png_handle_sPLT(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_tEXt_SUPPORTED
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else if (chunk_name == png_tEXt)
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png_handle_tEXt(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_tIME_SUPPORTED
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else if (chunk_name == png_tIME)
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png_handle_tIME(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_tRNS_SUPPORTED
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else if (chunk_name == png_tRNS)
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png_handle_tRNS(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_zTXt_SUPPORTED
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else if (chunk_name == png_zTXt)
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png_handle_zTXt(png_ptr, info_ptr, length);
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#endif
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#ifdef PNG_READ_iTXt_SUPPORTED
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else if (chunk_name == png_iTXt)
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png_handle_iTXt(png_ptr, info_ptr, length);
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#endif
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else
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png_handle_unknown(png_ptr, info_ptr, length);
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}
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}
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#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
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/* Optional call to update the users info_ptr structure */
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void PNGAPI
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png_read_update_info(png_structp png_ptr, png_infop info_ptr)
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{
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png_debug(1, "in png_read_update_info");
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if (png_ptr == NULL)
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return;
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png_read_start_row(png_ptr);
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#ifdef PNG_READ_TRANSFORMS_SUPPORTED
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png_read_transform_info(png_ptr, info_ptr);
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#else
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PNG_UNUSED(info_ptr)
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#endif
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}
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#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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/* Initialize palette, background, etc, after transformations
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* are set, but before any reading takes place. This allows
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* the user to obtain a gamma-corrected palette, for example.
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* If the user doesn't call this, we will do it ourselves.
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*/
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void PNGAPI
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png_start_read_image(png_structp png_ptr)
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{
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png_debug(1, "in png_start_read_image");
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if (png_ptr != NULL)
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png_read_start_row(png_ptr);
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}
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#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
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#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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void PNGAPI
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png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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{
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int ret;
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png_row_info row_info;
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if (png_ptr == NULL)
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return;
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png_debug2(1, "in png_read_row (row %lu, pass %d)",
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(unsigned long)png_ptr->row_number, png_ptr->pass);
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/* png_read_start_row sets the information (in particular iwidth) for this
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* interlace pass.
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*/
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if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
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png_read_start_row(png_ptr);
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/* 1.5.6: row_info moved out of png_struct to a local here. */
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row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
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row_info.color_type = png_ptr->color_type;
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row_info.bit_depth = png_ptr->bit_depth;
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row_info.channels = png_ptr->channels;
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row_info.pixel_depth = png_ptr->pixel_depth;
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row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
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if (png_ptr->row_number == 0 && png_ptr->pass == 0)
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{
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/* Check for transforms that have been set but were defined out */
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#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
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if (png_ptr->transformations & PNG_INVERT_MONO)
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png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
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#endif
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#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
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if (png_ptr->transformations & PNG_FILLER)
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png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
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#endif
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#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
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!defined(PNG_READ_PACKSWAP_SUPPORTED)
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if (png_ptr->transformations & PNG_PACKSWAP)
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png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
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#endif
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#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
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if (png_ptr->transformations & PNG_PACK)
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png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
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#endif
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#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
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if (png_ptr->transformations & PNG_SHIFT)
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png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
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#endif
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#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
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if (png_ptr->transformations & PNG_BGR)
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png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
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#endif
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#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
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if (png_ptr->transformations & PNG_SWAP_BYTES)
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png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
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#endif
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}
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#ifdef PNG_READ_INTERLACING_SUPPORTED
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/* If interlaced and we do not need a new row, combine row and return.
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* Notice that the pixels we have from previous rows have been transformed
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* already; we can only combine like with like (transformed or
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* untransformed) and, because of the libpng API for interlaced images, this
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* means we must transform before de-interlacing.
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*/
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if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
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{
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switch (png_ptr->pass)
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{
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case 0:
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if (png_ptr->row_number & 0x07)
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{
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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}
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break;
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case 1:
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if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
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{
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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}
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break;
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case 2:
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if ((png_ptr->row_number & 0x07) != 4)
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{
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if (dsp_row != NULL && (png_ptr->row_number & 4))
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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}
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break;
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case 3:
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if ((png_ptr->row_number & 3) || png_ptr->width < 3)
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{
|
|
if (dsp_row != NULL)
|
|
png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
|
png_read_finish_row(png_ptr);
|
|
return;
|
|
}
|
|
break;
|
|
|
|
case 4:
|
|
if ((png_ptr->row_number & 3) != 2)
|
|
{
|
|
if (dsp_row != NULL && (png_ptr->row_number & 2))
|
|
png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
|
png_read_finish_row(png_ptr);
|
|
return;
|
|
}
|
|
break;
|
|
case 5:
|
|
if ((png_ptr->row_number & 1) || png_ptr->width < 2)
|
|
{
|
|
if (dsp_row != NULL)
|
|
png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
|
png_read_finish_row(png_ptr);
|
|
return;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
case 6:
|
|
if (!(png_ptr->row_number & 1))
|
|
{
|
|
png_read_finish_row(png_ptr);
|
|
return;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
if (!(png_ptr->mode & PNG_HAVE_IDAT))
|
|
png_error(png_ptr, "Invalid attempt to read row data");
|
|
|
|
png_ptr->zstream.next_out = png_ptr->row_buf;
|
|
png_ptr->zstream.avail_out =
|
|
(uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
|
|
png_ptr->iwidth) + 1);
|
|
|
|
do
|
|
{
|
|
if (!(png_ptr->zstream.avail_in))
|
|
{
|
|
while (!png_ptr->idat_size)
|
|
{
|
|
png_crc_finish(png_ptr, 0);
|
|
|
|
png_ptr->idat_size = png_read_chunk_header(png_ptr);
|
|
if (png_ptr->chunk_name != png_IDAT)
|
|
png_error(png_ptr, "Not enough image data");
|
|
}
|
|
png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
|
|
png_ptr->zstream.next_in = png_ptr->zbuf;
|
|
if (png_ptr->zbuf_size > png_ptr->idat_size)
|
|
png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
|
|
png_crc_read(png_ptr, png_ptr->zbuf,
|
|
(png_size_t)png_ptr->zstream.avail_in);
|
|
png_ptr->idat_size -= png_ptr->zstream.avail_in;
|
|
}
|
|
|
|
ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
|
|
|
|
if (ret == Z_STREAM_END)
|
|
{
|
|
if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
|
|
png_ptr->idat_size)
|
|
png_benign_error(png_ptr, "Extra compressed data");
|
|
png_ptr->mode |= PNG_AFTER_IDAT;
|
|
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
|
|
break;
|
|
}
|
|
|
|
if (ret != Z_OK)
|
|
png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
|
|
"Decompression error");
|
|
|
|
} while (png_ptr->zstream.avail_out);
|
|
|
|
if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
|
|
{
|
|
if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
|
|
png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
|
|
png_ptr->prev_row + 1, png_ptr->row_buf[0]);
|
|
else
|
|
png_error(png_ptr, "bad adaptive filter value");
|
|
}
|
|
|
|
/* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
|
|
* 1.5.6, while the buffer really is this big in current versions of libpng
|
|
* it may not be in the future, so this was changed just to copy the
|
|
* interlaced count:
|
|
*/
|
|
png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
|
|
|
|
#ifdef PNG_MNG_FEATURES_SUPPORTED
|
|
if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
|
|
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
|
|
{
|
|
/* Intrapixel differencing */
|
|
png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
|
|
}
|
|
#endif
|
|
|
|
|
|
#ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
|
if (png_ptr->transformations)
|
|
png_do_read_transformations(png_ptr, &row_info);
|
|
#endif
|
|
|
|
/* The transformed pixel depth should match the depth now in row_info. */
|
|
if (png_ptr->transformed_pixel_depth == 0)
|
|
{
|
|
png_ptr->transformed_pixel_depth = row_info.pixel_depth;
|
|
if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
|
|
png_error(png_ptr, "sequential row overflow");
|
|
}
|
|
|
|
else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
|
|
png_error(png_ptr, "internal sequential row size calculation error");
|
|
|
|
#ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
/* Blow up interlaced rows to full size */
|
|
if (png_ptr->interlaced &&
|
|
(png_ptr->transformations & PNG_INTERLACE))
|
|
{
|
|
if (png_ptr->pass < 6)
|
|
png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
|
|
png_ptr->transformations);
|
|
|
|
if (dsp_row != NULL)
|
|
png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
|
if (row != NULL)
|
|
png_combine_row(png_ptr, row, 0/*row*/);
|
|
}
|
|
|
|
else
|
|
#endif
|
|
{
|
|
if (row != NULL)
|
|
png_combine_row(png_ptr, row, -1/*ignored*/);
|
|
|
|
if (dsp_row != NULL)
|
|
png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
|
|
}
|
|
png_read_finish_row(png_ptr);
|
|
|
|
if (png_ptr->read_row_fn != NULL)
|
|
(*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
|
|
}
|
|
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
|
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
/* Read one or more rows of image data. If the image is interlaced,
|
|
* and png_set_interlace_handling() has been called, the rows need to
|
|
* contain the contents of the rows from the previous pass. If the
|
|
* image has alpha or transparency, and png_handle_alpha()[*] has been
|
|
* called, the rows contents must be initialized to the contents of the
|
|
* screen.
|
|
*
|
|
* "row" holds the actual image, and pixels are placed in it
|
|
* as they arrive. If the image is displayed after each pass, it will
|
|
* appear to "sparkle" in. "display_row" can be used to display a
|
|
* "chunky" progressive image, with finer detail added as it becomes
|
|
* available. If you do not want this "chunky" display, you may pass
|
|
* NULL for display_row. If you do not want the sparkle display, and
|
|
* you have not called png_handle_alpha(), you may pass NULL for rows.
|
|
* If you have called png_handle_alpha(), and the image has either an
|
|
* alpha channel or a transparency chunk, you must provide a buffer for
|
|
* rows. In this case, you do not have to provide a display_row buffer
|
|
* also, but you may. If the image is not interlaced, or if you have
|
|
* not called png_set_interlace_handling(), the display_row buffer will
|
|
* be ignored, so pass NULL to it.
|
|
*
|
|
* [*] png_handle_alpha() does not exist yet, as of this version of libpng
|
|
*/
|
|
|
|
void PNGAPI
|
|
png_read_rows(png_structp png_ptr, png_bytepp row,
|
|
png_bytepp display_row, png_uint_32 num_rows)
|
|
{
|
|
png_uint_32 i;
|
|
png_bytepp rp;
|
|
png_bytepp dp;
|
|
|
|
png_debug(1, "in png_read_rows");
|
|
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
rp = row;
|
|
dp = display_row;
|
|
if (rp != NULL && dp != NULL)
|
|
for (i = 0; i < num_rows; i++)
|
|
{
|
|
png_bytep rptr = *rp++;
|
|
png_bytep dptr = *dp++;
|
|
|
|
png_read_row(png_ptr, rptr, dptr);
|
|
}
|
|
|
|
else if (rp != NULL)
|
|
for (i = 0; i < num_rows; i++)
|
|
{
|
|
png_bytep rptr = *rp;
|
|
png_read_row(png_ptr, rptr, NULL);
|
|
rp++;
|
|
}
|
|
|
|
else if (dp != NULL)
|
|
for (i = 0; i < num_rows; i++)
|
|
{
|
|
png_bytep dptr = *dp;
|
|
png_read_row(png_ptr, NULL, dptr);
|
|
dp++;
|
|
}
|
|
}
|
|
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
|
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
/* Read the entire image. If the image has an alpha channel or a tRNS
|
|
* chunk, and you have called png_handle_alpha()[*], you will need to
|
|
* initialize the image to the current image that PNG will be overlaying.
|
|
* We set the num_rows again here, in case it was incorrectly set in
|
|
* png_read_start_row() by a call to png_read_update_info() or
|
|
* png_start_read_image() if png_set_interlace_handling() wasn't called
|
|
* prior to either of these functions like it should have been. You can
|
|
* only call this function once. If you desire to have an image for
|
|
* each pass of a interlaced image, use png_read_rows() instead.
|
|
*
|
|
* [*] png_handle_alpha() does not exist yet, as of this version of libpng
|
|
*/
|
|
void PNGAPI
|
|
png_read_image(png_structp png_ptr, png_bytepp image)
|
|
{
|
|
png_uint_32 i, image_height;
|
|
int pass, j;
|
|
png_bytepp rp;
|
|
|
|
png_debug(1, "in png_read_image");
|
|
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
#ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
|
|
{
|
|
pass = png_set_interlace_handling(png_ptr);
|
|
/* And make sure transforms are initialized. */
|
|
png_start_read_image(png_ptr);
|
|
}
|
|
else
|
|
{
|
|
if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
|
|
{
|
|
/* Caller called png_start_read_image or png_read_update_info without
|
|
* first turning on the PNG_INTERLACE transform. We can fix this here,
|
|
* but the caller should do it!
|
|
*/
|
|
png_warning(png_ptr, "Interlace handling should be turned on when "
|
|
"using png_read_image");
|
|
/* Make sure this is set correctly */
|
|
png_ptr->num_rows = png_ptr->height;
|
|
}
|
|
|
|
/* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
|
|
* the above error case.
|
|
*/
|
|
pass = png_set_interlace_handling(png_ptr);
|
|
}
|
|
#else
|
|
if (png_ptr->interlaced)
|
|
png_error(png_ptr,
|
|
"Cannot read interlaced image -- interlace handler disabled");
|
|
|
|
pass = 1;
|
|
#endif
|
|
|
|
image_height=png_ptr->height;
|
|
|
|
for (j = 0; j < pass; j++)
|
|
{
|
|
rp = image;
|
|
for (i = 0; i < image_height; i++)
|
|
{
|
|
png_read_row(png_ptr, *rp, NULL);
|
|
rp++;
|
|
}
|
|
}
|
|
}
|
|
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
|
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
/* Read the end of the PNG file. Will not read past the end of the
|
|
* file, will verify the end is accurate, and will read any comments
|
|
* or time information at the end of the file, if info is not NULL.
|
|
*/
|
|
void PNGAPI
|
|
png_read_end(png_structp png_ptr, png_infop info_ptr)
|
|
{
|
|
png_debug(1, "in png_read_end");
|
|
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
|
|
|
|
#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
|
|
/* Report invalid palette index; added at libng-1.5.10 */
|
|
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
|
png_ptr->num_palette_max > png_ptr->num_palette)
|
|
png_benign_error(png_ptr, "Read palette index exceeding num_palette");
|
|
#endif
|
|
|
|
do
|
|
{
|
|
png_uint_32 length = png_read_chunk_header(png_ptr);
|
|
png_uint_32 chunk_name = png_ptr->chunk_name;
|
|
|
|
if (chunk_name == png_IHDR)
|
|
png_handle_IHDR(png_ptr, info_ptr, length);
|
|
|
|
else if (chunk_name == png_IEND)
|
|
png_handle_IEND(png_ptr, info_ptr, length);
|
|
|
|
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
|
else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
|
|
PNG_HANDLE_CHUNK_AS_DEFAULT)
|
|
{
|
|
if (chunk_name == png_IDAT)
|
|
{
|
|
if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
|
|
png_benign_error(png_ptr, "Too many IDATs found");
|
|
}
|
|
png_handle_unknown(png_ptr, info_ptr, length);
|
|
if (chunk_name == png_PLTE)
|
|
png_ptr->mode |= PNG_HAVE_PLTE;
|
|
}
|
|
#endif
|
|
|
|
else if (chunk_name == png_IDAT)
|
|
{
|
|
/* Zero length IDATs are legal after the last IDAT has been
|
|
* read, but not after other chunks have been read.
|
|
*/
|
|
if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
|
|
png_benign_error(png_ptr, "Too many IDATs found");
|
|
|
|
png_crc_finish(png_ptr, length);
|
|
}
|
|
else if (chunk_name == png_PLTE)
|
|
png_handle_PLTE(png_ptr, info_ptr, length);
|
|
|
|
#ifdef PNG_READ_bKGD_SUPPORTED
|
|
else if (chunk_name == png_bKGD)
|
|
png_handle_bKGD(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_cHRM_SUPPORTED
|
|
else if (chunk_name == png_cHRM)
|
|
png_handle_cHRM(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_gAMA_SUPPORTED
|
|
else if (chunk_name == png_gAMA)
|
|
png_handle_gAMA(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_hIST_SUPPORTED
|
|
else if (chunk_name == png_hIST)
|
|
png_handle_hIST(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_oFFs_SUPPORTED
|
|
else if (chunk_name == png_oFFs)
|
|
png_handle_oFFs(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_pCAL_SUPPORTED
|
|
else if (chunk_name == png_pCAL)
|
|
png_handle_pCAL(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_sCAL_SUPPORTED
|
|
else if (chunk_name == png_sCAL)
|
|
png_handle_sCAL(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_pHYs_SUPPORTED
|
|
else if (chunk_name == png_pHYs)
|
|
png_handle_pHYs(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_sBIT_SUPPORTED
|
|
else if (chunk_name == png_sBIT)
|
|
png_handle_sBIT(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_sRGB_SUPPORTED
|
|
else if (chunk_name == png_sRGB)
|
|
png_handle_sRGB(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_iCCP_SUPPORTED
|
|
else if (chunk_name == png_iCCP)
|
|
png_handle_iCCP(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_sPLT_SUPPORTED
|
|
else if (chunk_name == png_sPLT)
|
|
png_handle_sPLT(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_tEXt_SUPPORTED
|
|
else if (chunk_name == png_tEXt)
|
|
png_handle_tEXt(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_tIME_SUPPORTED
|
|
else if (chunk_name == png_tIME)
|
|
png_handle_tIME(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_tRNS_SUPPORTED
|
|
else if (chunk_name == png_tRNS)
|
|
png_handle_tRNS(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_zTXt_SUPPORTED
|
|
else if (chunk_name == png_zTXt)
|
|
png_handle_zTXt(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_iTXt_SUPPORTED
|
|
else if (chunk_name == png_iTXt)
|
|
png_handle_iTXt(png_ptr, info_ptr, length);
|
|
#endif
|
|
|
|
else
|
|
png_handle_unknown(png_ptr, info_ptr, length);
|
|
} while (!(png_ptr->mode & PNG_HAVE_IEND));
|
|
}
|
|
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
|
/* Free all memory used by the read */
|
|
void PNGAPI
|
|
png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
|
|
png_infopp end_info_ptr_ptr)
|
|
{
|
|
png_structp png_ptr = NULL;
|
|
png_infop info_ptr = NULL, end_info_ptr = NULL;
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
png_free_ptr free_fn = NULL;
|
|
png_voidp mem_ptr = NULL;
|
|
#endif
|
|
|
|
png_debug(1, "in png_destroy_read_struct");
|
|
|
|
if (png_ptr_ptr != NULL)
|
|
png_ptr = *png_ptr_ptr;
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
free_fn = png_ptr->free_fn;
|
|
mem_ptr = png_ptr->mem_ptr;
|
|
#endif
|
|
|
|
if (info_ptr_ptr != NULL)
|
|
info_ptr = *info_ptr_ptr;
|
|
|
|
if (end_info_ptr_ptr != NULL)
|
|
end_info_ptr = *end_info_ptr_ptr;
|
|
|
|
png_read_destroy(png_ptr, info_ptr, end_info_ptr);
|
|
|
|
if (info_ptr != NULL)
|
|
{
|
|
#ifdef PNG_TEXT_SUPPORTED
|
|
png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
|
|
#endif
|
|
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
|
|
(png_voidp)mem_ptr);
|
|
#else
|
|
png_destroy_struct((png_voidp)info_ptr);
|
|
#endif
|
|
*info_ptr_ptr = NULL;
|
|
}
|
|
|
|
if (end_info_ptr != NULL)
|
|
{
|
|
#ifdef PNG_READ_TEXT_SUPPORTED
|
|
png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
|
|
#endif
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
|
|
(png_voidp)mem_ptr);
|
|
#else
|
|
png_destroy_struct((png_voidp)end_info_ptr);
|
|
#endif
|
|
*end_info_ptr_ptr = NULL;
|
|
}
|
|
|
|
if (png_ptr != NULL)
|
|
{
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
|
|
(png_voidp)mem_ptr);
|
|
#else
|
|
png_destroy_struct((png_voidp)png_ptr);
|
|
#endif
|
|
*png_ptr_ptr = NULL;
|
|
}
|
|
}
|
|
|
|
/* Free all memory used by the read (old method) */
|
|
void /* PRIVATE */
|
|
png_read_destroy(png_structp png_ptr, png_infop info_ptr,
|
|
png_infop end_info_ptr)
|
|
{
|
|
#ifdef PNG_SETJMP_SUPPORTED
|
|
jmp_buf tmp_jmp;
|
|
#endif
|
|
png_error_ptr error_fn;
|
|
#ifdef PNG_WARNINGS_SUPPORTED
|
|
png_error_ptr warning_fn;
|
|
#endif
|
|
png_voidp error_ptr;
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
png_free_ptr free_fn;
|
|
#endif
|
|
|
|
png_debug(1, "in png_read_destroy");
|
|
|
|
if (info_ptr != NULL)
|
|
png_info_destroy(png_ptr, info_ptr);
|
|
|
|
if (end_info_ptr != NULL)
|
|
png_info_destroy(png_ptr, end_info_ptr);
|
|
|
|
#ifdef PNG_READ_GAMMA_SUPPORTED
|
|
png_destroy_gamma_table(png_ptr);
|
|
#endif
|
|
|
|
png_free(png_ptr, png_ptr->zbuf);
|
|
png_free(png_ptr, png_ptr->big_row_buf);
|
|
png_free(png_ptr, png_ptr->big_prev_row);
|
|
png_free(png_ptr, png_ptr->chunkdata);
|
|
|
|
#ifdef PNG_READ_QUANTIZE_SUPPORTED
|
|
png_free(png_ptr, png_ptr->palette_lookup);
|
|
png_free(png_ptr, png_ptr->quantize_index);
|
|
#endif
|
|
|
|
if (png_ptr->free_me & PNG_FREE_PLTE)
|
|
png_zfree(png_ptr, png_ptr->palette);
|
|
png_ptr->free_me &= ~PNG_FREE_PLTE;
|
|
|
|
#if defined(PNG_tRNS_SUPPORTED) || \
|
|
defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
|
|
if (png_ptr->free_me & PNG_FREE_TRNS)
|
|
png_free(png_ptr, png_ptr->trans_alpha);
|
|
png_ptr->free_me &= ~PNG_FREE_TRNS;
|
|
#endif
|
|
|
|
#ifdef PNG_READ_hIST_SUPPORTED
|
|
if (png_ptr->free_me & PNG_FREE_HIST)
|
|
png_free(png_ptr, png_ptr->hist);
|
|
png_ptr->free_me &= ~PNG_FREE_HIST;
|
|
#endif
|
|
|
|
inflateEnd(&png_ptr->zstream);
|
|
|
|
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
|
|
png_free(png_ptr, png_ptr->save_buffer);
|
|
#endif
|
|
|
|
/* Save the important info out of the png_struct, in case it is
|
|
* being used again.
|
|
*/
|
|
#ifdef PNG_SETJMP_SUPPORTED
|
|
png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
|
|
#endif
|
|
|
|
error_fn = png_ptr->error_fn;
|
|
#ifdef PNG_WARNINGS_SUPPORTED
|
|
warning_fn = png_ptr->warning_fn;
|
|
#endif
|
|
error_ptr = png_ptr->error_ptr;
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
free_fn = png_ptr->free_fn;
|
|
#endif
|
|
|
|
png_memset(png_ptr, 0, png_sizeof(png_struct));
|
|
|
|
png_ptr->error_fn = error_fn;
|
|
#ifdef PNG_WARNINGS_SUPPORTED
|
|
png_ptr->warning_fn = warning_fn;
|
|
#endif
|
|
png_ptr->error_ptr = error_ptr;
|
|
#ifdef PNG_USER_MEM_SUPPORTED
|
|
png_ptr->free_fn = free_fn;
|
|
#endif
|
|
|
|
#ifdef PNG_SETJMP_SUPPORTED
|
|
png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
|
|
#endif
|
|
|
|
}
|
|
|
|
void PNGAPI
|
|
png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
|
|
{
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
png_ptr->read_row_fn = read_row_fn;
|
|
}
|
|
|
|
|
|
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
#ifdef PNG_INFO_IMAGE_SUPPORTED
|
|
void PNGAPI
|
|
png_read_png(png_structp png_ptr, png_infop info_ptr,
|
|
int transforms,
|
|
voidp params)
|
|
{
|
|
int row;
|
|
|
|
if (png_ptr == NULL || info_ptr == NULL)
|
|
return;
|
|
|
|
/* png_read_info() gives us all of the information from the
|
|
* PNG file before the first IDAT (image data chunk).
|
|
*/
|
|
png_read_info(png_ptr, info_ptr);
|
|
if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
|
|
png_error(png_ptr, "Image is too high to process with png_read_png()");
|
|
|
|
/* -------------- image transformations start here ------------------- */
|
|
|
|
#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
|
/* Tell libpng to strip 16-bit/color files down to 8 bits per color.
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_SCALE_16)
|
|
{
|
|
/* Added at libpng-1.5.4. "strip_16" produces the same result that it
|
|
* did in earlier versions, while "scale_16" is now more accurate.
|
|
*/
|
|
png_set_scale_16(png_ptr);
|
|
}
|
|
#endif
|
|
|
|
#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
|
/* If both SCALE and STRIP are required pngrtran will effectively cancel the
|
|
* latter by doing SCALE first. This is ok and allows apps not to check for
|
|
* which is supported to get the right answer.
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_STRIP_16)
|
|
png_set_strip_16(png_ptr);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
|
/* Strip alpha bytes from the input data without combining with
|
|
* the background (not recommended).
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
|
|
png_set_strip_alpha(png_ptr);
|
|
#endif
|
|
|
|
#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
|
|
/* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
|
|
* byte into separate bytes (useful for paletted and grayscale images).
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_PACKING)
|
|
png_set_packing(png_ptr);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_PACKSWAP_SUPPORTED
|
|
/* Change the order of packed pixels to least significant bit first
|
|
* (not useful if you are using png_set_packing).
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_PACKSWAP)
|
|
png_set_packswap(png_ptr);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_EXPAND_SUPPORTED
|
|
/* Expand paletted colors into true RGB triplets
|
|
* Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
|
|
* Expand paletted or RGB images with transparency to full alpha
|
|
* channels so the data will be available as RGBA quartets.
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_EXPAND)
|
|
if ((png_ptr->bit_depth < 8) ||
|
|
(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
|
|
(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
|
|
png_set_expand(png_ptr);
|
|
#endif
|
|
|
|
/* We don't handle background color or gamma transformation or quantizing.
|
|
*/
|
|
|
|
#ifdef PNG_READ_INVERT_SUPPORTED
|
|
/* Invert monochrome files to have 0 as white and 1 as black
|
|
*/
|
|
if (transforms & PNG_TRANSFORM_INVERT_MONO)
|
|
png_set_invert_mono(png_ptr);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_SHIFT_SUPPORTED
|
|
/* If you want to shift the pixel values from the range [0,255] or
|
|
* [0,65535] to the original [0,7] or [0,31], or whatever range the
|
|
* colors were originally in:
|
|
*/
|
|
if ((transforms & PNG_TRANSFORM_SHIFT)
|
|
&& png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
|
|
{
|
|
png_color_8p sig_bit;
|
|
|
|
png_get_sBIT(png_ptr, info_ptr, &sig_bit);
|
|
png_set_shift(png_ptr, sig_bit);
|
|
}
|
|
#endif
|
|
|
|
#ifdef PNG_READ_BGR_SUPPORTED
|
|
/* Flip the RGB pixels to BGR (or RGBA to BGRA) */
|
|
if (transforms & PNG_TRANSFORM_BGR)
|
|
png_set_bgr(png_ptr);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
|
|
/* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
|
|
if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
|
|
png_set_swap_alpha(png_ptr);
|
|
#endif
|
|
|
|
#ifdef PNG_READ_SWAP_SUPPORTED
|
|
/* Swap bytes of 16-bit files to least significant byte first */
|
|
if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
|
|
png_set_swap(png_ptr);
|
|
#endif
|
|
|
|
/* Added at libpng-1.2.41 */
|
|
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
|
/* Invert the alpha channel from opacity to transparency */
|
|
if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
|
|
png_set_invert_alpha(png_ptr);
|
|
#endif
|
|
|
|
/* Added at libpng-1.2.41 */
|
|
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
|
/* Expand grayscale image to RGB */
|
|
if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
|
|
png_set_gray_to_rgb(png_ptr);
|
|
#endif
|
|
|
|
/* Added at libpng-1.5.4 */
|
|
#ifdef PNG_READ_EXPAND_16_SUPPORTED
|
|
if (transforms & PNG_TRANSFORM_EXPAND_16)
|
|
png_set_expand_16(png_ptr);
|
|
#endif
|
|
|
|
/* We don't handle adding filler bytes */
|
|
|
|
/* We use png_read_image and rely on that for interlace handling, but we also
|
|
* call png_read_update_info therefore must turn on interlace handling now:
|
|
*/
|
|
(void)png_set_interlace_handling(png_ptr);
|
|
|
|
/* Optional call to gamma correct and add the background to the palette
|
|
* and update info structure. REQUIRED if you are expecting libpng to
|
|
* update the palette for you (i.e., you selected such a transform above).
|
|
*/
|
|
png_read_update_info(png_ptr, info_ptr);
|
|
|
|
/* -------------- image transformations end here ------------------- */
|
|
|
|
png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
|
|
if (info_ptr->row_pointers == NULL)
|
|
{
|
|
png_uint_32 iptr;
|
|
|
|
info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
|
|
info_ptr->height * png_sizeof(png_bytep));
|
|
for (iptr=0; iptr<info_ptr->height; iptr++)
|
|
info_ptr->row_pointers[iptr] = NULL;
|
|
|
|
info_ptr->free_me |= PNG_FREE_ROWS;
|
|
|
|
for (row = 0; row < (int)info_ptr->height; row++)
|
|
info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
|
|
png_get_rowbytes(png_ptr, info_ptr));
|
|
}
|
|
|
|
png_read_image(png_ptr, info_ptr->row_pointers);
|
|
info_ptr->valid |= PNG_INFO_IDAT;
|
|
|
|
/* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
|
|
png_read_end(png_ptr, info_ptr);
|
|
|
|
PNG_UNUSED(transforms) /* Quiet compiler warnings */
|
|
PNG_UNUSED(params)
|
|
|
|
}
|
|
#endif /* PNG_INFO_IMAGE_SUPPORTED */
|
|
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
#endif /* PNG_READ_SUPPORTED */
|