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libpng/pngstruct.h
John Bowler dff6f4c4f0 [libpng16Cleanup of png_set_filler(). This function does very different things 
on read and write.  In libpng 1.6 the two cases can be distinguished and
considerable code cleanup, and extra error checking, is possible.  This
makes calls on the write side that have no effect be ignored with a
png_app_error(), which can be disabled in the app using
png_set_benign_errors(), and removes the spurious use of usr_channels
on the read side.
2012-08-09 21:17:56 -05:00

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/* pngstruct.h - header file for PNG reference library
*
* Copyright (c) 1998-2012 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* Last changed in libpng 1.6.0 [(PENDING RELEASE)]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
/* The structure that holds the information to read and write PNG files.
* The only people who need to care about what is inside of this are the
* people who will be modifying the library for their own special needs.
* It should NOT be accessed directly by an application.
*/
#ifndef PNGSTRUCT_H
#define PNGSTRUCT_H
/* zlib.h defines the structure z_stream, an instance of which is included
* in this structure and is required for decompressing the LZ compressed
* data in PNG files.
*/
#ifndef ZLIB_CONST
/* We must ensure that zlib uses 'const' in declarations. */
# define ZLIB_CONST
#endif
#include "zlib.h"
#ifdef const
/* zlib.h sometimes #defines const to nothing, undo this. */
# undef const
#endif
/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
* with older builds.
*/
#if ZLIB_VERNUM < 0x1260
# define PNGZ_MSG_CAST(s) png_constcast(char*,s)
# define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
#else
# define PNGZ_MSG_CAST(s) (s)
# define PNGZ_INPUT_CAST(b) (b)
#endif
/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
* can handle at once. This type need be no larger than 16 bits (so maximum of
* 65535), this define allows us to discover how big it is, but limited by the
* maximuum for png_size_t. The value can be overriden in a library build
* (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
* lower value (e.g. 255 works). A lower value may help memory usage (slightly)
* and may even improve performance on some systems (and degrade it on others.)
*/
#ifndef ZLIB_IO_MAX
# define ZLIB_IO_MAX ((uInt)-1)
#endif
#ifdef PNG_WRITE_SUPPORTED
/* The type of a compression buffer list used by the write code. */
typedef struct png_compression_buffer
{
struct png_compression_buffer *next;
png_byte output[1]; /* actually zbuf_size */
} png_compression_buffer, *png_compression_bufferp;
#define PNG_COMPRESSION_BUFFER_SIZE(pp)\
(offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
#endif
/* Colorspace support; structures used in png_struct, png_info and in internal
* functions to hold and communicate information about the color space.
*
* PNG_COLORSPACE_SUPPORTED is only required if the application will perform
* colorspace corrections, otherwise all the colorspace information can be
* skipped and the size of libpng can be reduced (significantly) by compiling
* out the colorspace support.
*/
#ifdef PNG_COLORSPACE_SUPPORTED
/* The chromaticities of the red, green and blue colorants and the chromaticity
* of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
*/
typedef struct png_xy
{
png_fixed_point redx, redy;
png_fixed_point greenx, greeny;
png_fixed_point bluex, bluey;
png_fixed_point whitex, whitey;
} png_xy;
/* The same data as above but encoded as CIE XYZ values. When this data comes
* from chromaticities the sum of the Y values is assumed to be 1.0
*/
typedef struct png_XYZ
{
png_fixed_point redX, redY, redZ;
png_fixed_point greenX, greenY, greenZ;
png_fixed_point blueX, blueY, blueZ;
} png_XYZ;
#endif /* COLORSPACE */
#if defined PNG_COLORSPACE_SUPPORTED || defined PNG_GAMMA_SUPPORTED
/* A colorspace is all the above plus, potentially, profile information,
* however at present libpng does not use the profile internally so it is only
* stored in the png_info struct (if iCCP is supported.) The rendering intent
* is retained here and is checked.
*
* The file gamma encoding information is also stored here and gamma correction
* is done by libpng, whereas color correction must currently be done by the
* application.
*/
typedef struct png_colorspace
{
#ifdef PNG_GAMMA_SUPPORTED
png_fixed_point gamma; /* File gamma */
#endif
#ifdef PNG_COLORSPACE_SUPPORTED
png_xy end_points_xy; /* End points as chromaticities */
png_XYZ end_points_XYZ; /* End points as CIE XYZ colorant values */
png_uint_16 rendering_intent; /* Rendering intent of a profile */
#endif
/* Flags are always defined to simplify the code. */
png_uint_16 flags; /* As defined below */
} png_colorspace, * PNG_RESTRICT png_colorspacerp;
typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
#define PNG_COLORSPACE_HAVE_GAMMA 0x0001
#define PNG_COLORSPACE_HAVE_ENDPOINTS 0x0002
#define PNG_COLORSPACE_HAVE_INTENT 0x0004
#define PNG_COLORSPACE_FROM_gAMA 0x0008
#define PNG_COLORSPACE_FROM_cHRM 0x0010
#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0020
#define PNG_COLORSPACE_MATCHES_sRGB 0x0040 /* exact match on profile */
#define PNG_COLORSPACE_INVALID 0x8000
#define PNG_COLORSPACE_CANCEL(flags) (0xffff ^ (flags))
#endif /* COLORSPACE || GAMMA */
struct png_struct_def
{
#ifdef PNG_SETJMP_SUPPORTED
jmp_buf jmp_buf_local; /* New name in 1.6.0 for jmp_buf in png_struct */
png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
jmp_buf *jmp_buf_ptr; /* passed to longjmp_fn */
size_t jmp_buf_size; /* size of the above, if allocated */
#endif
png_error_ptr error_fn; /* function for printing errors and aborting */
#ifdef PNG_WARNINGS_SUPPORTED
png_error_ptr warning_fn; /* function for printing warnings */
#endif
png_voidp error_ptr; /* user supplied struct for error functions */
png_rw_ptr write_data_fn; /* function for writing output data */
png_rw_ptr read_data_fn; /* function for reading input data */
png_voidp io_ptr; /* ptr to application struct for I/O functions */
#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
png_user_transform_ptr read_user_transform_fn; /* user read transform */
#endif
#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
png_user_transform_ptr write_user_transform_fn; /* user write transform */
#endif
/* These were added in libpng-1.0.2 */
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
png_voidp user_transform_ptr; /* user supplied struct for user transform */
png_byte user_transform_depth; /* bit depth of user transformed pixels */
png_byte user_transform_channels; /* channels in user transformed pixels */
#endif
#endif
png_uint_32 mode; /* tells us where we are in the PNG file */
png_uint_32 flags; /* flags indicating various things to libpng */
png_uint_32 transformations; /* which transformations to perform */
png_uint_32 zowner; /* ID (chunk type) of zstream owner, 0 if none */
z_stream zstream; /* decompression structure */
#ifdef PNG_WRITE_SUPPORTED
png_compression_bufferp zbuffer_list; /* Created on demand during write */
uInt zbuffer_size; /* size of the actual buffer */
int zlib_level; /* holds zlib compression level */
int zlib_method; /* holds zlib compression method */
int zlib_window_bits; /* holds zlib compression window bits */
int zlib_mem_level; /* holds zlib compression memory level */
int zlib_strategy; /* holds zlib compression strategy */
#endif
/* Added at libpng 1.5.4 */
#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
int zlib_text_level; /* holds zlib compression level */
int zlib_text_method; /* holds zlib compression method */
int zlib_text_window_bits; /* holds zlib compression window bits */
int zlib_text_mem_level; /* holds zlib compression memory level */
int zlib_text_strategy; /* holds zlib compression strategy */
#endif
/* End of material added at libpng 1.5.4 */
/* Added at libpng 1.6.0 */
#ifdef PNG_WRITE_SUPPORTED
int zlib_set_level; /* Actual values set into the zstream on write */
int zlib_set_method;
int zlib_set_window_bits;
int zlib_set_mem_level;
int zlib_set_strategy;
#endif
png_uint_32 width; /* width of image in pixels */
png_uint_32 height; /* height of image in pixels */
png_uint_32 num_rows; /* number of rows in current pass */
png_uint_32 usr_width; /* width of row at start of write */
png_size_t rowbytes; /* size of row in bytes */
png_uint_32 iwidth; /* width of current interlaced row in pixels */
png_uint_32 row_number; /* current row in interlace pass */
png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */
png_bytep prev_row; /* buffer to save previous (unfiltered) row.
* This is a pointer into big_prev_row
*/
png_bytep row_buf; /* buffer to save current (unfiltered) row.
* This is a pointer into big_row_buf
*/
#ifdef PNG_WRITE_SUPPORTED
png_bytep sub_row; /* buffer to save "sub" row when filtering */
png_bytep up_row; /* buffer to save "up" row when filtering */
png_bytep avg_row; /* buffer to save "avg" row when filtering */
png_bytep paeth_row; /* buffer to save "Paeth" row when filtering */
#endif
png_size_t info_rowbytes; /* Added in 1.5.4: cache of updated row bytes */
png_uint_32 idat_size; /* current IDAT size for read */
png_uint_32 crc; /* current chunk CRC value */
png_colorp palette; /* palette from the input file */
png_uint_16 num_palette; /* number of color entries in palette */
/* Added at libpng-1.5.10 */
#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
int num_palette_max; /* maximum palette index found in IDAT */
#endif
png_uint_16 num_trans; /* number of transparency values */
png_byte compression; /* file compression type (always 0) */
png_byte filter; /* file filter type (always 0) */
png_byte interlaced; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
png_byte pass; /* current interlace pass (0 - 6) */
png_byte do_filter; /* row filter flags (see PNG_FILTER_ below ) */
png_byte color_type; /* color type of file */
png_byte bit_depth; /* bit depth of file */
png_byte usr_bit_depth; /* bit depth of users row: write only */
png_byte pixel_depth; /* number of bits per pixel */
png_byte channels; /* number of channels in file */
#ifdef PNG_WRITE_SUPPORTED
png_byte usr_channels; /* channels at start of write: write only */
#endif
png_byte sig_bytes; /* magic bytes read/written from start of file */
png_byte maximum_pixel_depth;
/* pixel depth used for the row buffers */
png_byte transformed_pixel_depth;
/* pixel depth after read/write transforms */
#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
png_uint_16 filler; /* filler bytes for pixel expansion */
#endif
#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
png_byte background_gamma_type;
png_fixed_point background_gamma;
png_color_16 background; /* background color in screen gamma space */
#ifdef PNG_READ_GAMMA_SUPPORTED
png_color_16 background_1; /* background normalized to gamma 1.0 */
#endif
#endif /* PNG_bKGD_SUPPORTED */
#ifdef PNG_WRITE_FLUSH_SUPPORTED
png_flush_ptr output_flush_fn; /* Function for flushing output */
png_uint_32 flush_dist; /* how many rows apart to flush, 0 - no flush */
png_uint_32 flush_rows; /* number of rows written since last flush */
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */
png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
png_bytep gamma_table; /* gamma table for 8-bit depth files */
png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
png_bytep gamma_from_1; /* converts from 1.0 to screen */
png_bytep gamma_to_1; /* converts from file to 1.0 */
png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
png_color_8 sig_bit; /* significant bits in each available channel */
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
png_color_8 shift; /* shift for significant bit tranformation */
#endif
#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
|| defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
png_bytep trans_alpha; /* alpha values for paletted files */
png_color_16 trans_color; /* transparent color for non-paletted files */
#endif
png_read_status_ptr read_row_fn; /* called after each row is decoded */
png_write_status_ptr write_row_fn; /* called after each row is encoded */
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
png_progressive_info_ptr info_fn; /* called after header data fully read */
png_progressive_row_ptr row_fn; /* called after a prog. row is decoded */
png_progressive_end_ptr end_fn; /* called after image is complete */
png_bytep save_buffer_ptr; /* current location in save_buffer */
png_bytep save_buffer; /* buffer for previously read data */
png_bytep current_buffer_ptr; /* current location in current_buffer */
png_bytep current_buffer; /* buffer for recently used data */
png_uint_32 push_length; /* size of current input chunk */
png_uint_32 skip_length; /* bytes to skip in input data */
png_size_t save_buffer_size; /* amount of data now in save_buffer */
png_size_t save_buffer_max; /* total size of save_buffer */
png_size_t buffer_size; /* total amount of available input data */
png_size_t current_buffer_size; /* amount of data now in current_buffer */
int process_mode; /* what push library is currently doing */
int cur_palette; /* current push library palette index */
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
/* For the Borland special 64K segment handler */
png_bytepp offset_table_ptr;
png_bytep offset_table;
png_uint_16 offset_table_number;
png_uint_16 offset_table_count;
png_uint_16 offset_table_count_free;
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
png_bytep palette_lookup; /* lookup table for quantizing */
png_bytep quantize_index; /* index translation for palette files */
#endif
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_byte heuristic_method; /* heuristic for row filter selection */
png_byte num_prev_filters; /* number of weights for previous rows */
png_bytep prev_filters; /* filter type(s) of previous row(s) */
png_uint_16p filter_weights; /* weight(s) for previous line(s) */
png_uint_16p inv_filter_weights; /* 1/weight(s) for previous line(s) */
png_uint_16p filter_costs; /* relative filter calculation cost */
png_uint_16p inv_filter_costs; /* 1/relative filter calculation cost */
#endif
#if PNG_LIBPNG_VER < 10700
/* To do: remove this from libpng-1.7 */
#ifdef PNG_TIME_RFC1123_SUPPORTED
char time_buffer[29]; /* String to hold RFC 1123 time text */
#endif
#endif
/* New members added in libpng-1.0.6 */
png_uint_32 free_me; /* flags items libpng is responsible for freeing */
#ifdef PNG_USER_CHUNKS_SUPPORTED
png_voidp user_chunk_ptr;
png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
#endif
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
unsigned int num_chunk_list;
png_bytep chunk_list;
#endif
/* New members added in libpng-1.0.3 */
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
png_byte rgb_to_gray_status;
/* Added in libpng 1.5.5 to record setting of coefficients: */
png_byte rgb_to_gray_coefficients_set;
/* These were changed from png_byte in libpng-1.0.6 */
png_uint_16 rgb_to_gray_red_coeff;
png_uint_16 rgb_to_gray_green_coeff;
/* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
#endif
/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
#if defined(PNG_MNG_FEATURES_SUPPORTED)
/* Changed from png_byte to png_uint_32 at version 1.2.0 */
png_uint_32 mng_features_permitted;
#endif
/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
#ifdef PNG_MNG_FEATURES_SUPPORTED
png_byte filter_type;
#endif
/* New members added in libpng-1.2.0 */
/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
#ifdef PNG_USER_MEM_SUPPORTED
png_voidp mem_ptr; /* user supplied struct for mem functions */
png_malloc_ptr malloc_fn; /* function for allocating memory */
png_free_ptr free_fn; /* function for freeing memory */
#endif
/* New member added in libpng-1.0.13 and 1.2.0 */
png_bytep big_row_buf; /* buffer to save current (unfiltered) row */
#ifdef PNG_READ_QUANTIZE_SUPPORTED
/* The following three members were added at version 1.0.14 and 1.2.4 */
png_bytep quantize_sort; /* working sort array */
png_bytep index_to_palette; /* where the original index currently is
in the palette */
png_bytep palette_to_index; /* which original index points to this
palette color */
#endif
/* New members added in libpng-1.0.16 and 1.2.6 */
png_byte compression_type;
#ifdef PNG_USER_LIMITS_SUPPORTED
png_uint_32 user_width_max;
png_uint_32 user_height_max;
/* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
* chunks that can be stored (0 means unlimited).
*/
png_uint_32 user_chunk_cache_max;
/* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
* can occupy when decompressed. 0 means unlimited.
*/
png_alloc_size_t user_chunk_malloc_max;
#endif
/* New member added in libpng-1.0.25 and 1.2.17 */
#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
/* Temporary storage for unknown chunk that the library doesn't recognize,
* used while reading the chunk.
*/
#ifdef PNG_READ_SUPPORTED
png_unknown_chunk unknown_chunk;
#endif
#endif
/* New member added in libpng-1.2.26 */
png_size_t old_big_row_buf_size;
#ifdef PNG_READ_SUPPORTED
/* New member added in libpng-1.2.30 */
png_bytep read_buffer; /* buffer for reading chunk data */
png_alloc_size_t read_buffer_size; /* current size of the buffer */
#endif
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
uInt IDAT_read_size; /* limit on read buffer size for IDAT */
#endif
#ifdef PNG_IO_STATE_SUPPORTED
/* New member added in libpng-1.4.0 */
png_uint_32 io_state;
#endif
/* New member added in libpng-1.5.6 */
png_bytep big_prev_row;
void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
png_bytep row, png_const_bytep prev_row);
#ifdef PNG_READ_SUPPORTED
#if defined PNG_COLORSPACE_SUPPORTED || defined PNG_GAMMA_SUPPORTED
png_colorspace colorspace;
#endif
#endif
};
#endif /* PNGSTRUCT_H */
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