/* pngstruct.h - header file for PNG reference library * * Copyright (c) 1998-2013 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 1.7.0 [(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 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 * accesed.) */ 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 /* PNG_READ_SUPPORTED */ #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_SUPPORTED /* This is somewhat excessive, there is no obvious reason on write to * allocate a buffer for each possible filtered row, only for the one being * tested and the current best. * * TODO: fix this */ 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 /* 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 /* PNG_READ_GAMMA_SUPPORTED */ #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 */