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libpng/pngstruct.h
Glenn Randers-Pehrson 9c7aee825c [libpng17] Bump version to 1.7.0beta52
2015-02-17 10:52:59 -06:00

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/* pngstruct.h - header file for PNG reference library
*
* Last changed in libpng 1.7.0 [(PENDING RELEASE)]
* Copyright (c) 1998-2015 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.)
*
* 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 PNG_ZLIB_HEADER
#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
* maximum for size_t. The value can be overridden 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 red_X, red_Y, red_Z;
png_fixed_point green_X, green_Y, green_Z;
png_fixed_point blue_X, blue_Y, blue_Z;
} 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;
/* General flags for the 'flags' field */
#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_FROM_sRGB 0x0020
#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
#define PNG_COLORSPACE_MATCHES_sRGB 0x0080 /* exact match on profile */
#define PNG_COLORSPACE_RGB_TO_GRAY_SET 0x0100 /* user specified coeffs */
#define PNG_COLORSPACE_INVALID 0x8000
#define PNG_COLORSPACE_CANCEL(flags) (0xffff ^ (flags))
#endif /* COLORSPACE || GAMMA */
struct png_struct_def
{
/* Rearranged in libpng 1.7 to attempt to lessen padding; in general
* (char), (short), (int) and pointer types are kept separate; however
* associated members under the control of the same #define are still
* together.
*/
#ifdef PNG_SETJMP_SUPPORTED
/* jmp_buf can have very high alignment requirements on some systems, so put
* it first (the other setjmp members are later as they are infrequently
* accessed.)
*/
jmp_buf jmp_buf_local;
#endif
/* Next the frequently accessed fields. Many processors perform arithmetic
* in the address pipeline, but frequently the amount of addition or
* subtraction is limited. By putting these fields at the head of png_struct
* the hope is that such processors will generate code that is both smaller
* and faster.
*/
png_colorp palette; /* palette from the input file */
size_t rowbytes; /* size of row in bytes */
size_t info_rowbytes; /* cache of updated row bytes */
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_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_uint_32 crc; /* current chunk CRC value */
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 */
png_uint_32 free_me; /* items libpng is responsible for freeing */
int maximum_pixel_depth; /* pixel depth used for the row buffers */
#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
int num_palette_max; /* maximum palette index found in IDAT */
#endif
png_uint_16 num_palette; /* number of color entries in palette */
png_uint_16 num_trans; /* number of transparency values */
/* Single byte values, typically used either to save space or to hold 1-byte
* values from the PNG chunk specifications.
*/
png_byte compression_type; /* 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 pixel_depth; /* number of bits per pixel */
png_byte channels; /* number of channels in file */
png_byte sig_bytes; /* magic bytes read/written from start of file */
png_byte transformed_pixel_depth;
/* pixel depth after read/write transforms */
/* ERROR HANDLING */
#ifdef PNG_SETJMP_SUPPORTED
jmp_buf *jmp_buf_ptr; /* passed to longjmp_fn */
png_longjmp_ptr longjmp_fn; /* setjmp non-local goto function. */
size_t jmp_buf_size; /* size of *jmp_buf_ptr, if allocated */
#endif
/* Error/warning callbacks */
png_error_ptr error_fn; /* print an error message and abort */
#ifdef PNG_WARNINGS_SUPPORTED
png_error_ptr warning_fn; /* print a warning and continue */
#endif
png_voidp error_ptr; /* user supplied data for the above */
/* MEMORY ALLOCATION */
#ifdef PNG_USER_MEM_SUPPORTED
png_malloc_ptr malloc_fn; /* allocate memory */
png_free_ptr free_fn; /* free memory */
png_voidp mem_ptr; /* user supplied data for the above */
#endif
/* IO and BASIC READ/WRITE SUPPORT */
png_voidp io_ptr; /* user supplied data for IO callbacks */
#ifdef PNG_READ_SUPPORTED
png_rw_ptr read_data_fn; /* read some bytes (must succeed) */
png_read_status_ptr read_row_fn; /* called after each row is decoded */
png_bytep read_buffer; /* buffer for reading chunk data */
/* During read the following array is set up to point to the appropriate
* un-filter function, this allows per-image and per-processor optimization.
*/
void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
png_bytep row, png_const_bytep prev_row);
#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
/* The png_struct colorspace structure is only required on read - on write it
* is in (just) the info_struct.
*/
png_colorspace colorspace;
#endif
#endif /* READ */
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
png_uint_32 user_width_max; /* Maximum width on read */
png_uint_32 user_height_max; /* Maximum height on read */
/* Total memory that a single zTXt, sPLT, iTXt, iCCP, or unknown chunk
* can occupy when decompressed. 0 means unlimited. This field is a counter
* - it is decremented as memory is allocated.
*/
png_alloc_size_t user_chunk_malloc_max;
#endif
#ifdef PNG_USER_LIMITS_SUPPORTED
/* limit on total *number* of sPLT, text and unknown chunks that can be
* stored. 0 means unlimited. This field is a counter - it is decremented
* as chunks are encountered.
*/
png_uint_32 user_chunk_cache_max;
#endif
/* The progressive reader gets passed data and calls application handling
* functions when appropriate.
*/
#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 row is decoded */
png_progressive_end_ptr end_fn; /* called after image is complete */
/* Progressive read control data */
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 */
size_t save_buffer_size; /* amount of data now in save_buffer */
size_t save_buffer_max; /* total size of save_buffer */
size_t buffer_size; /* total amount of available input data */
size_t current_buffer_size; /* amount of data now in current_buffer */
png_uint_32 push_length; /* size of current input chunk */
png_uint_32 skip_length; /* bytes to skip in input data */
int process_mode; /* what push library is currently doing */
int cur_palette; /* current push library palette index */
#endif
#ifdef PNG_WRITE_SUPPORTED
png_rw_ptr write_data_fn;/* write some bytes (must succeed) */
png_write_status_ptr write_row_fn; /* called after each row is encoded */
#endif
#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_WRITE_WEIGHTED_FILTER_SUPPORTED
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 */
png_byte heuristic_method; /* heuristic for row filter selection */
png_byte num_prev_filters; /* number of weights for previous rows */
#endif
#ifdef PNG_WRITE_SUPPORTED
png_byte usr_bit_depth; /* bit depth of users row */
png_byte usr_channels; /* channels at start of write */
#endif
#ifdef PNG_IO_STATE_SUPPORTED
png_uint_32 io_state; /* tells the app read/write progress */
#endif
/* ROW BUFFERS
*
* Members that hold pointers to the decompressed image rows.
*/
png_bytep row_buf; /* buffer for the current (unfiltered) row */
#if defined(PNG_WRITE_FILTER_SUPPORTED) || defined(PNG_READ_SUPPORTED)
png_bytep prev_row; /* buffer to save the previous (unfiltered) row */
#endif
#ifdef PNG_READ_SUPPORTED
/* The row_buf and prev_row pointers are misaligned so that the start of the
* row - after the filter byte - is aligned, the 'big_' pointers record the
* original allocated pointer.
*/
png_bytep big_row_buf;
png_bytep big_prev_row;
size_t big_row_buf_size; /* Actual size of both */
#endif
#ifdef PNG_WRITE_FILTER_SUPPORTED
png_bytep try_row; /* buffer to save trial row when filtering */
png_bytep tst_row; /* buffer to save best trial row when filtering */
#endif
/* UNKNOWN CHUNK HANDLING */
/* TODO: this is excessively complicated, there are multiple ways of doing
* the same thing. It should be cleaned up, possibly by finding out which
* APIs applications really use.
*/
#ifdef PNG_USER_CHUNKS_SUPPORTED
/* General purpose pointer for all user/unknown chunk handling; points to
* application supplied data for use in the read_user_chunk_fn callback
* (currently there is no write side support - the write side must use the
* set_unknown_chunks interface.)
*/
png_voidp user_chunk_ptr;
#endif
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
/* This is called back from the unknown chunk handling */
png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
#endif
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
/* Temporary storage for unknown chunk that the library doesn't recognize,
* used while reading the chunk.
*/
png_unknown_chunk unknown_chunk;
#endif
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
png_bytep chunk_list; /* List of png_byte[5]; the textual chunk name
* followed by a PNG_HANDLE_* byte */
int unknown_default; /* As PNG_HANDLE_* */
unsigned int num_chunk_list; /* Number of entries in the list */
#endif
/* USER TRANSFORM SUPPORT */
#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
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
png_voidp user_transform_ptr; /* user supplied data for the above */
png_byte user_transform_depth; /* bit depth of user transformed pixels */
png_byte user_transform_channels; /* channels in user transformed pixels */
#endif
/* READ TRANSFORM SUPPORT
*
* Quite a lot of things can be done to the original image data on read, and
* most of these are configurable. The data required by the configurable
* read transforms should be stored here. The png_color_16 and png_color_8
* structures have low alignment requirements and odd sizes, so may cause
* misalignment when present. Member alignment is as follows:
*
* png_color_16 png_uint_16
* png_color_8 png_byte
*/
/* GAMMA/BACKGROUND/ALPHA-MODE/RGB-TO-GRAY/tRNS/sBIT
*
* These things are all interrelated because they need some or all of the
* gamma tables. Some attempt has been made below to order these members by
* size, so that as little padding as possible is required.
*/
#ifdef PNG_READ_GAMMA_SUPPORTED
png_bytep gamma_table; /* gamma table for 8-bit depth files */
png_uint_16p 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_uint_16p gamma_to_1; /* converts from file to 1.0 */
png_uint_16p gamma_16_from_1; /* converts from 1.0 to screen */
png_uint_16p gamma_16_to_1; /* converts from file to 1.0 */
#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
#endif /* READ_GAMMA */
#if defined(PNG_READ_tRNS_SUPPORTED) || \
defined(PNG_READ_BACKGROUND_SUPPORTED) || \
defined(PNG_READ_EXPAND_SUPPORTED)
png_bytep trans_alpha; /* alpha values for paletted files */
#endif
/* Integer values */
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
png_fixed_point background_gamma;
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */
#endif
/* png_color_16 */
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
png_color_16 background; /* background color in screen gamma space */
png_color_16 background_1; /* background normalized to gamma 1.0 */
#endif
#if defined(PNG_READ_tRNS_SUPPORTED) || \
defined(PNG_READ_BACKGROUND_SUPPORTED) || \
defined(PNG_READ_EXPAND_SUPPORTED)
png_color_16 trans_color; /* transparent color for non-paletted files */
#endif
/* png_uint_16 */
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
png_uint_16 rgb_to_gray_red_coeff;
png_uint_16 rgb_to_gray_green_coeff;
/* The blue coefficient is calculated from the above */
#endif
/* png_color_8 */
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_sBIT_SUPPORTED)
png_color_8 sig_bit; /* significant bits in each available channel */
#endif
/* png_byte */
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
png_byte background_gamma_type;
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
png_byte rgb_to_gray_status;
#endif
/* SHIFT - both READ_SHIFT and WRITE_SHIFT */
#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
png_color_8 shift; /* shift for significant bit tranformation */
#endif
/* FILLER SUPPORT (pixel expansion or read, contraction on write) */
#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
png_uint_16 filler; /* filler bytes for pixel expansion */
#endif
/* QUANTIZE (convert to color-mapped) */
#ifdef PNG_READ_QUANTIZE_SUPPORTED
png_bytep palette_lookup; /* lookup table for quantizing */
png_bytep quantize_index; /* index translation for palette files */
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
/* MNG SUPPORT */
#ifdef PNG_MNG_FEATURES_SUPPORTED
png_uint_32 mng_features_permitted;
png_byte filter_type;
#endif
/* Options */
#ifdef PNG_SET_OPTION_SUPPORTED
png_byte options; /* On/off state (up to 4 options) */
#endif
/* COMPRESSION AND DECOMPRESSION SUPPORT.
*
* zlib expects a 'zstream' as the fundamental control structure, it allows
* all the parameters to be passed as one pointer.
*/
z_stream zstream; /* decompression structure */
#ifdef PNG_READ_SUPPORTED
/* These, and IDAT_read_size below, control how much input and output (at
* most) is available to zlib.
*/
png_uint_32 idat_size; /* current IDAT size for read */
png_alloc_size_t read_buffer_size; /* current size of the buffer */
#endif
#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
#ifdef PNG_WRITE_SUPPORTED
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 */
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;
png_compression_bufferp zbuffer_list; /* Created on demand during write */
uInt zbuffer_size; /* size of the actual zlib buffer */
#endif
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
uInt IDAT_read_size; /* limit on read buffer size for IDAT */
#endif
};
#endif /* PNGSTRUCT_H */
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