/* pngstruct.h - header file for PNG reference library * * Last changed in libpng 1.7.0 [(PENDING RELEASE)] * Copyright (c) 1998-2002,2004,2006-2016 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 /* !ZLIB_CONST */ #include PNG_ZLIB_HEADER #ifdef const /* zlib.h sometimes #defines const to nothing, undo this. */ # undef const #endif /* const */ /* 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 /* ZLIB_VERNUM >= 0x1260 */ # define PNGZ_MSG_CAST(s) (s) # define PNGZ_INPUT_CAST(b) (b) #endif /* ZLIB_VERNUM >= 0x1260 */ /* 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 # ifdef __COVERITY__ # define ZLIB_IO_MAX ((uInt)255U) /* else COVERITY whines */ # else /* !COVERITY */ # define ZLIB_IO_MAX ((uInt)-1) # endif /* !COVERITY */ #endif /* !ZLIB_IO_MAX */ #ifdef PNG_WRITE_SUPPORTED /* The write compression control (allocated on demand). * TODO: use this for the read state too. */ typedef struct png_zlib_state *png_zlib_statep; #endif /* WRITE */ /* 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 /* GAMMA */ #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 /* COLORSPACE */ /* 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 0x0001U #define PNG_COLORSPACE_HAVE_ENDPOINTS 0x0002U #define PNG_COLORSPACE_HAVE_INTENT 0x0004U #define PNG_COLORSPACE_FROM_gAMA 0x0008U #define PNG_COLORSPACE_FROM_cHRM 0x0010U #define PNG_COLORSPACE_FROM_sRGB 0x0020U #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040U #define PNG_COLORSPACE_MATCHES_sRGB 0x0080U /* exact match on profile */ #define PNG_COLORSPACE_RGB_TO_GRAY_SET 0x0100U /* user specified coeffs */ #define PNG_COLORSPACE_INVALID 0x8000U #define PNG_COLORSPACE_CANCEL(flags) (0xffffU - (flags)) #endif /* COLORSPACE || GAMMA */ #ifdef PNG_TRANSFORM_MECH_SUPPORTED /***************************** READ and WRITE TRANSFORMS *********************** * These structures are used in pngrtran.c, pngwtran.c and pngtrans.c to hold * information about transforms in progress. This mechanism was introduced in * libpng 1.7.0 to ensure reliable transform code and to fix multiple bugs in * the pre-1.7 transform handling. * * Prior to 1.7.0 the internal transform routines took a png_row_infop, like the * user transform function, but without the png_ptr because it was never used. * In 1.7.0 a separate internal structure is used in place of this to allow both * future development to change the structure. * * The values in this structure will normally be changed by transformation * implementations. ***************************** READ and WRITE TRANSFORMS **********************/ typedef struct { png_structp png_ptr; /* png_struct for error handling and some * transform parameters. May be aliased. */ png_const_voidp sp; /* Source; the input row. */ png_voidp dp; /* Output buffer for the transformed row, * this may be the same as sp. */ /* If the row is changed the tranform routine must write the result to * dp[] and set sp to dp, otherwise it must not write to dp and must leave * sp unchanged. dp[] and sp[] are both 'malloc' aligned; i.e. they have * the system alignment, so the data can be read as any valid ANSI-C * type. */ png_uint_32 width; /* width of row */ # ifdef PNG_READ_GAMMA_SUPPORTED png_fixed_point gamma; /* Current gamma of the row data */ /* When a row is being transformed this contains the current gamma of the * data if known. During initialization the value is used to accumulate * information for png_struct::row_gamma in the first step, * PNG_TC_INIT_FORMAT, then used to insert the correct gamma transforms * during PNG_TC_INIT_FINAL. The field is only used on read; write * transforms do not modify the gamma of the data. */ # endif /* READ_GAMMA */ unsigned int format; /* As pngstruct::row_format below */ unsigned int range; /* Count of range transforms */ # define PNG_TC_CHANNELS(tc) PNG_FORMAT_CHANNELS((tc).format) unsigned int bit_depth; /* bit depth of row */ png_byte sBIT_R; png_byte sBIT_G; png_byte sBIT_B; png_byte sBIT_A; /* Signnificant bits in the row channels. */ /* The above four values are initially set to the number of bits significant * in the input PNG data, R/G/B are set to the same (gray) value for * grayscale input. All values are set to the bit depth if there is no sBIT * chunk, if there is no alpha channel sBIT_A is set to the bit depth. * * When any potentially spurious bits have been cleared PNG_INFO_sBIT will be * set in invalid_info. From this point on the above values record the * approximate number of bits of accuracy in the channels and the lower bits * should be preserved; they potentially contain useful information. */ # define PNG_TC_PIXEL_DEPTH(tc) (PNG_TC_CHANNELS(tc) * (tc).bit_depth) # define PNG_TC_ROWBYTES(tc) PNG_ROWBYTES(PNG_TC_PIXEL_DEPTH(tc), (tc).width) unsigned int invalid_info; /* PNG_INFO_* for invalidated chunks */ unsigned int cost; /* Cache cost */ # define PNG_CACHE_COST_LIMIT 0x100U /* This is a runtime structure, so size doesn't matter much, and it helps * code reliability to use real member names here. Feel free to experiment * with integer values rather than bitfields. */ unsigned int init :2; /* 0 for processing, non zero for init: */ # define PNG_TC_INIT_FORMAT 0x01U /* Initialization step 1: just set 'format', * 'bit_depth' and 'gamma' to the output * values iff the transform corresponds to * a user requested change to those values. */ # define PNG_TC_INIT_FINAL 0x03U /* Initialization step 2; set the 'format' * 'bit_depth' and 'gamma' to the values the * transform will actually produce (which * need not be the same as the above). */ /* During initialization 'init' must be set and sp and dp may be NULL. If * neither flag is set sp and dp must be non-NULL. * * When the transform runs it must update 'format', 'bit_depth' and 'gamma' * to the values previously reported during PNG_TC_INIT_FINAL; not doing so * may result in an affirm from a later transform. */ unsigned int caching :1; /* The color values are being used to * generate a cache of the transforms. */ unsigned int palette :1; /* The values come from a PNG palette and * the palette will not be expanded. The * CACHE flag must be set too. A * transform which causes the palette to * be expanded must clear this flag. */ #if 0 /* NYI */ unsigned int interchannel:1; /* Set by a transform that combines two or * more channels together; for example * alpha composition or RGB to gray. */ #endif /* NYI */ unsigned int channel_add :1; /* A channel (alpha/filler) was added */ unsigned int strip_alpha :1; /* Set if the alpha channel will be * stripped on read, this also prevents * the tRNS chunk being expanded. Only * some transforms check this, depending * on the handling order and checks in * pre-1.7 versions. */ unsigned int expand_tRNS :1; /* Set if the tRNS chunk should be * expanded (ignored if read_strip_alpha * is set). If this is *not* set * transforms which do not use alpha/tRNS * but would invalidate it (such as * simple gamma correction) will simply * mark the tRNS info as invalid. */ unsigned int transparent_alpha :1; /* Indicates that the alpha channel * consists entirely of opaque (1.0 alpha) * or completely transparent (0.0 alpha) * pixels. Set when tRNS is expanded to * alpha. */ unsigned int optimized_alpha :1; /* Meaningful only when bit_depth is * 16 and gamma is 1 or unknown (0). * Indicates that pixels which are opaque * (alpha 1.0) have not been expanded to * 16-bit linear; instead these pixels * are encoded in the final format in * png_struct::row_bit_depth and * png_struct::row_gamma. This will * invariably match the file format. */ } png_transform_control, *png_transform_controlp; typedef const png_transform_control *png_const_transform_controlp; typedef const png_row_info *png_const_row_infop; typedef struct png_transform *png_transformp; /* Forward declaration */ typedef void (*png_transform_free_fn)(/* Function to free a transform */ png_const_structrp png_ptr, png_transformp transform); /* pointer to this transform */ /* This function need not exist in a transform, it must free all the data * allocated within the transform but not the transform itself. It is called * from png_transform_free. */ typedef void (*png_transform_fn)(/* Function to implement a transform */ png_transformp *transform, /* pointer to this transform */ png_transform_controlp control); /* row information */ /* The transform function has two modes of operation: * * 1) Initialization. The list of transforms is processed from the start to * the end and each function is called with one of hte PNG_TC_INIT_ flags * set in control->flags, control->dp and control->sp may be NULL. * * For read the control structure contains the input row format and bit * depth, the transform function changes this to represent what the * transform will produce when it runs. * * For write the control structure contains the *required* output format * and bit depth. The transform function changes this to the values that * it needs to produce the required values. * * In both cases the transform function may update the 'fn' function to a * new function to perform the desired transform; this allows considerable * optimization on multi-row images. * * In both cases the caller considers the pixel bit depth changes and * records the maximum required so that it can allocate a suitably sized * buffer. * * 2) Execution. * * In the read case the transforms are processed in the stored order and * must transform the row data appropriately *and* update the bit depth * and format as before. * * In the write case the transforms are called in the reverse order and * the input bit depth and format should match the required values. * * It is valid during initialization for the transform function to push * another transform into the list in either the read or the write case if * the transform cannot handle (read) or produce (write) the required format. * The transform pushes another transform into the list ahead of itself (at * *transform) and runs that initialization; when control is returned to the * caller the caller will re-run the transform initialization. * * It is also valid (during initialization) to push new transforms onto the * list, just so long as the order of the transform is greater than the * current transform (so that the caller will still call the new transform * initialization.) * * In the write case the user transform callback might still end up producing * an unexpected format, but at present this is unavoidable; the libpng API * is extremely inconsistent in how a user transform reports the changes it * made. * * TODO: fix this, probably with an API change in 1.7.0 */ typedef struct png_transform /* Linked list of transform functions */ { png_transformp next; /* Next transform in the list */ png_transform_fn fn; /* Function to implement the transform */ png_transform_free_fn free; /* Free allocated data, normally NULL */ unsigned int order; /* Order of the transform in the list. */ unsigned int size; /* Size of this structure (max 65535) */ png_uint_32 args; /* Optional transform arguments. */ } png_transform; #endif /* TRANSFORM_MECH */ /* Action to take on CRC errors (four values) */ typedef enum { crc_error_quit = PNG_CRC_ERROR_QUIT-1, crc_warn_discard = PNG_CRC_WARN_DISCARD-1, crc_warn_use = PNG_CRC_WARN_USE-1, crc_quiet_use = PNG_CRC_QUIET_USE-1 } png_crc_action; 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 /* SETJMP */ /* 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. */ #ifdef PNG_READ_SUPPORTED png_colorp palette; /* palette from the input file */ #endif /* READ */ #ifdef PNG_READ_tRNS_SUPPORTED png_bytep trans_alpha; /* alpha values for paletted files */ #endif /* READ_tRNS */ png_uint_32 width; /* width of image in pixels */ png_uint_32 height; /* height of image in pixels */ png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */ #ifdef PNG_READ_SUPPORTED png_uint_32 chunk_length; /* Length (possibly remaining) in said chunk. */ #endif /* READ */ png_uint_32 crc; /* current chunk CRC value */ unsigned int mode :6; /* where we are in the PNG file */ unsigned int read_struct :1; /* this is a read (not write) struct */ unsigned int num_palette :9; /* number of color entries in palette */ #ifdef PNG_READ_tRNS_SUPPORTED unsigned int num_trans :9; /* number of transparency values */ unsigned int transparent_palette :1; /* if they are all 0 or 255 */ #endif /* READ_tRNS */ #ifdef PNG_PALETTE_MAX_SUPPORTED unsigned int palette_index_max :8; /* maximum palette index in IDAT */ unsigned int palette_index_check :2; /* one of the following: */ # define PNG_PALETTE_CHECK_DEFAULT 0U # define PNG_PALETTE_CHECK_OFF 1U # define PNG_PALETTE_CHECK_ON 2U unsigned int palette_index_have_max :1; /* max is being set */ unsigned int palette_index_check_issued :1; /* error message output */ #endif /* PALETTE_MAX */ #ifdef PNG_READ_tRNS_SUPPORTED png_color_16 trans_color; /* transparent color for non-paletted files */ #endif /* READ_tRNS */ #ifdef PNG_READ_sBIT_SUPPORTED png_color_8 sig_bit; /* significant bits in each channel */ #endif /* READ_sBIT */ /* Single byte values, typically used either to save space or to hold 1-byte * values from the PNG chunk specifications. */ png_byte filter_method; /* file filter type (only non-0 with MNG) */ png_byte interlaced; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */ png_byte color_type; /* color type of file */ png_byte bit_depth; /* bit depth of file */ png_byte sig_bytes; /* magic bytes read/written at start of file */ #ifdef PNG_READ_SUPPORTED #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 /* COLORSPACE || GAMMA */ #endif /* READ */ /* Transform handling */ #ifdef PNG_TRANSFORM_MECH_SUPPORTED png_transformp transform_list; /* List of transformation to perform. */ #endif /* TRANSFORM_MECH */ /* ROW BUFFERS and CONTROL * * Members used for image row compression (write) or decompression (read). * filter byte (which is in next_filter.) All fields are only used during * IDAT processing and start of 0. */ #ifdef PNG_READ_SUPPORTED png_bytep row_buffer; /* primary row buffer */ #if (defined(PNG_PROGRESSIVE_READ_SUPPORTED) ||\ defined(PNG_READ_INTERLACING_SUPPORTED)) &&\ defined(PNG_TRANSFORM_MECH_SUPPORTED) png_bytep transformed_row; /* pointer to the transformed row, if * required. May point to row_buffer. */ #endif /* (PROGRESSIVE_READ || READ_INTERLACING) && TRANSFORM_MECH */ png_alloc_size_t row_bytes_read; /* Total read in row */ #endif /* READ */ png_uint_32 row_number; /* current row in pass */ #ifdef PNG_READ_SUPPORTED #ifdef PNG_READ_GAMMA_SUPPORTED png_fixed_point row_gamma; /* Gamma of final output */ #if 0 /* NYI */ unsigned int gamma_accuracy; /* LINEAR gamma cache table size (in bits) times 100; for non-linear * tables the value used is gamma_accuracy/gamma where 'gamma' is the * encoding value of the data (typically less than 1). * * default: PNG_DEFAULT_GAMMA_ACCURACY (665) */ #endif /* NYI */ png_uint_16 gamma_threshold; /* Gamma threshold value as a fixed-point value in the range 0..1; the * threshold at or below which gamma correction is skipped. '0' forces * gamma correction even when there is none because the input and output * gammas are equal. * * default: PNG_GAMMA_THRESHOLD_FIXED (153) */ #endif /* READ_GAMMA */ #ifdef PNG_READ_TRANSFORMS_SUPPORTED unsigned int invalid_info; /* PNG_INFO_* for invalidated chunks */ unsigned int palette_updated:1; /* png_struct::palette changed */ #endif /* READ_TRANSFORMS */ #ifdef PNG_SEQUENTIAL_READ_SUPPORTED unsigned int read_started :1; /* at least one call to png_read_row */ #endif /* SEQUENTIAL_READ */ /* The next field is just used by the read IDAT process functions to store * the state of IDAT processing; they should not be altered or used by other * functions. */ unsigned int row_state :2; /* state of row parsing (internal) */ #endif /* READ */ #if defined (PNG_READ_INTERLACING_SUPPORTED) ||\ defined (PNG_WRITE_INTERLACING_SUPPORTED) unsigned int do_interlace :1; /* libpng handles the interlace */ # endif /* R/W INTERLACING */ unsigned int pass :3; /* current (interlace) pass (0 - 6) */ /* The following fields are set by png_row_init to the pixel depths of the * pixels at various states. If transforms are not supported they will * always be the same value: * * READ WRITE * input: PNG From application * output: To application PNG * max: Largest in transform */ unsigned int row_input_pixel_depth :8; unsigned int row_output_pixel_depth :8; unsigned int row_max_pixel_depth :8; # define PNG_RF_BITS 9 /* Number of bits required for the row format (below) */ #ifdef PNG_TRANSFORM_MECH_SUPPORTED /* The following fields describe the format of the user row; the output on * read or the input on write, and give the maximum pixel depth, which * controls the row buffer allocation size (row_allocated_bytes) above. */ unsigned int row_range :3; /* range error count */ unsigned int row_bit_depth :6; /* bits per channel (up to 32) */ unsigned int row_format:PNG_RF_BITS;/* format of output(R)/input(W) row: */ /* PNG_FORMAT_FLAG_ALPHA 0x01U format with an alpha channel * PNG_FORMAT_FLAG_COLOR 0x02U color format: otherwise grayscale * PNG_FORMAT_FLAG_LINEAR 0x04U NOT used (informational) * PNG_FORMAT_FLAG_COLORMAP 0x08U image data is color-mapped * PNG_FORMAT_FLAG_BGR 0x10U BGR colors, else order is RGB * PNG_FORMAT_FLAG_AFIRST 0x20U alpha channel comes first * * PNG_FORAMT_FLAG_AFILLER 0x40U The 'alpha' channel is a filler: * PNG_FORMAT_FLAG_ALPHA is set however the value in the alpha channel * is not an alpha value and (therefore) cannot be used for alpha * computations, it is just a filler value. PNG_COLOR_TYPE_FROM_FORMAT * will return a color type *without* PNG_COLOR_MASK_ALPHA, however * PNG_FORMAT_CHANNELS will return the correct number, including the * filler channel. * PNG_FORMAT_FLAG_SWAPPED 0x80U bytes or bits swapped: * When the bit depth is 16 this means that the bytes within the * components have been swapped, when the bit depth is less than 8 * it means the pixels within the bytes have been swapped. It should * not be set for 8-bit compononents (it is meaningless). * PNG_FORMAT_FLAG_RANGE 0x100U component range not 0..bit-depth: * Low-bit-depth grayscale components have been unpacked into bytes * without scaling, or RGB[A] pixels have been shifted back to the * significant-bit range from the sBIT chunk or channels (currently * alpha or gray) have been inverted. * PNG_FORMAT_FLAG_INVALID NOT STORED HERE */ #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED unsigned int info_format:PNG_RF_BITS; /* This field is used to validate the png_info used to write the * IHDR. This is a new check in 1.7.0; previously it was possible to pass * a png_info from a png_read with the read tranform information in the * format having manually removed the required transforms from the rows * passed to png_write_row. */ #endif /* WRITE_TRANSFORMS */ #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED unsigned int write_invert_alpha :1; /* This indicates the png_set_invert_alpha was called, it is used by the * write code to implement the transform without needing to run the whole * transform mechanism on the PNG palette data. */ #endif /* WRITE_INVERT_ALPHA */ #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED unsigned int rgb_to_gray_status :1; /* If set an RGB pixel was encountered by the RGB to gray transform * wherein !(r==g==b). */ #endif /* RGB_TO_GRAY */ #endif /* TRANSFORM_MECH */ #ifdef PNG_READ_SUPPORTED /* These, and IDAT_size below, control how much input and output (at most) is * available to zlib during read decompression. */ png_alloc_size_t read_buffer_size; /* current size of the buffer */ #endif /* READ */ #if defined(PNG_SEQUENTIAL_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) png_uint_32 IDAT_size; /* limit on IDAT read and write IDAT size */ #endif /* SEQUENTIAL_READ || WRITE */ /* 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 /* SETJMP */ /* 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 /* WARNINGS */ 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 /* USER_MEM */ /* IO and BASIC READ/WRITE SUPPORT */ png_voidp io_ptr; /* user supplied data for IO callbacks */ png_rw_ptr rw_data_fn; /* read/write some bytes (must succeed) */ #ifdef PNG_READ_SUPPORTED 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_alloc_size_t row_bytes, unsigned int bpp, png_bytep row, png_const_bytep prev_row, png_const_bytep prev_pixels); #endif /* READ */ #ifdef PNG_WRITE_SUPPORTED png_write_status_ptr write_row_fn; /* called after each row is encoded */ #ifdef PNG_WRITE_FLUSH_SUPPORTED png_flush_ptr output_flush_fn; /* Function for flushing output */ #endif /* WRITE_FLUSH */ #endif /* WRITE */ #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 /* SET_USER_LIMITS */ #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 /* USER_LIMITS */ /* 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 */ size_t save_buffer_size; /* amount of data now in save_buffer */ size_t save_buffer_max; /* total size of save_buffer */ size_t current_buffer_size; /* amount of data now in current_buffer */ size_t buffer_size; /* total amount of available input data */ unsigned int process_mode :8; /* This is one or two four bit codes describing the current state of the * 'push' reader. Normally the low four bits are a state code, however in * some cases this may be pushed to the top four bits and replaced by a * different temporary state code. The value is, in effect, a two entry * stack. */ #endif /* PROGRESSIVE_READ */ #ifdef PNG_IO_STATE_SUPPORTED png_uint_32 io_state; /* tells the app read/write progress */ #endif /* IO_STATE */ /* 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 /* USER_CHUNKS */ #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 /* READ_USER_CHUNKS */ #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED png_uint_32 known_unknown; /* Bit mask of known chunks to be treated as * unknown in the read code. */ #ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED png_uint_32 save_unknown; /* Whether to save or skip these chunks: * 'save' is 'known & save', 'skip' is * 'known & ~save'. */ # define png_IDATs_skipped(pp) (((pp)->known_unknown & ~(pp)->save_unknown)&1U) #else /* !SAVE_UNKNOWN_CHUNKS */ # define png_IDATs_skipped(pp) ((pp)->known_unknown & 1U) #endif /* !SAVE_UNKNOWN_CHUNKS */ #endif /* HANDLE_AS_UNKNOWN */ #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 */ unsigned int unknown_default :2; /* As PNG_HANDLE_* */ unsigned int num_chunk_list; /* Number of entries in the list */ #endif /* SET_UNKNOWN_CHUNKS */ /* COMPRESSION AND DECOMPRESSION SUPPORT. * * zlib expects a 'zstream' as the fundamental control structure, it allows * all the parameters to be passed as one pointer. */ png_uint_32 zowner; /* ID (chunk type) of zlib owner, 0 if none */ # ifdef PNG_WRITE_SUPPORTED png_zlib_statep zlib_state; /* State of zlib compression */ # endif /* WRITE */ # ifdef PNG_READ_SUPPORTED z_stream zstream; /* decompression structure */ unsigned int zstream_ended:1; /* no more zlib output available [read] */ unsigned int zstream_error:1; /* zlib error message has been output [read] */ # endif /* READ */ # ifdef PNG_PROGRESSIVE_READ_SUPPORTED unsigned int zstream_eod :1; /* all the required uncompressed data has been * received; set by the zstream using code for * its own purposes. [progressive read] */ # endif /* PROGRESSIVE_READ */ # ifdef PNG_BENIGN_ERRORS_SUPPORTED unsigned int benign_error_action :2; unsigned int app_warning_action :2; unsigned int app_error_action :2; # ifdef PNG_READ_SUPPORTED unsigned int IDAT_error_action :2; # endif /* READ */ # endif /* BENIGN_ERRORS */ # ifdef PNG_READ_SUPPORTED /* CRC checking actions, one for critical chunks, one for ancillary * chunks. */ unsigned int critical_crc :2; unsigned int ancillary_crc :2; unsigned int current_crc :2; /* Cache of one or other of the above */ # endif # ifdef PNG_SET_OPTION_SUPPORTED # ifdef PNG_READ_SUPPORTED unsigned int maximum_inflate_window :1U; # endif /* READ */ unsigned int skip_sRGB_profile_check :1U; # endif /* SET_OPTION */ /* MNG SUPPORT */ #ifdef PNG_MNG_FEATURES_SUPPORTED unsigned int mng_features_permitted :3; #endif /* MNG_FEATURES */ /* SCRATCH buffers, used when control returns to the application or a read * loop. */ # ifdef PNG_READ_SUPPORTED png_byte scratch[PNG_ROW_BUFFER_SIZE+16U]; # endif /* READ */ }; #endif /* PNGSTRUCT_H */