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  1. /*
  2.  * jpeglib.h
  3.  *
  4.  * Copyright (C) 1991-1998, Thomas G. Lane.
  5.  * This file is part of the Independent JPEG Group's software.
  6.  * For conditions of distribution and use, see the accompanying README file.
  7.  *
  8.  * This file defines the application interface for the JPEG library.
  9.  * Most applications using the library need only include this file,
  10.  * and perhaps jerror.h if they want to know the exact error codes.
  11.  */
  12.  
  13. #ifndef JPEGLIB_H
  14. #define JPEGLIB_H
  15.  
  16. /*
  17.  * First we include the configuration files that record how this
  18.  * installation of the JPEG library is set up.  jconfig.h can be
  19.  * generated automatically for many systems.  jmorecfg.h contains
  20.  * manual configuration options that most people need not worry about.
  21.  */
  22.  
  23. #ifndef JCONFIG_INCLUDED        /* in case jinclude.h already did */
  24. #include "jconfig.h"            /* widely used configuration options */
  25. #endif
  26. #include "jmorecfg.h"           /* seldom changed options */
  27.  
  28.  
  29. /* Version ID for the JPEG library.
  30.  * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
  31.  */
  32.  
  33. #define JPEG_LIB_VERSION  62    /* Version 6b */
  34.  
  35.  
  36. /* Various constants determining the sizes of things.
  37.  * All of these are specified by the JPEG standard, so don't change them
  38.  * if you want to be compatible.
  39.  */
  40.  
  41. #define DCTSIZE             8   /* The basic DCT block is 8x8 samples */
  42. #define DCTSIZE2            64  /* DCTSIZE squared; # of elements in a block */
  43. #define NUM_QUANT_TBLS      4   /* Quantization tables are numbered 0..3 */
  44. #define NUM_HUFF_TBLS       4   /* Huffman tables are numbered 0..3 */
  45. #define NUM_ARITH_TBLS      16  /* Arith-coding tables are numbered 0..15 */
  46. #define MAX_COMPS_IN_SCAN   4   /* JPEG limit on # of components in one scan */
  47. #define MAX_SAMP_FACTOR     4   /* JPEG limit on sampling factors */
  48. /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
  49.  * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
  50.  * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
  51.  * to handle it.  We even let you do this from the jconfig.h file.  However,
  52.  * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
  53.  * sometimes emits noncompliant files doesn't mean you should too.
  54.  */
  55. #define C_MAX_BLOCKS_IN_MCU   10 /* compressor's limit on blocks per MCU */
  56. #ifndef D_MAX_BLOCKS_IN_MCU
  57. #define D_MAX_BLOCKS_IN_MCU   10 /* decompressor's limit on blocks per MCU */
  58. #endif
  59.  
  60.  
  61. /* Data structures for images (arrays of samples and of DCT coefficients).
  62.  * On 80x86 machines, the image arrays are too big for near pointers,
  63.  * but the pointer arrays can fit in near memory.
  64.  */
  65.  
  66. typedef JSAMPLE FAR *JSAMPROW;  /* ptr to one image row of pixel samples. */
  67. typedef JSAMPROW *JSAMPARRAY;   /* ptr to some rows (a 2-D sample array) */
  68. typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
  69.  
  70. typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
  71. typedef JBLOCK FAR *JBLOCKROW;  /* pointer to one row of coefficient blocks */
  72. typedef JBLOCKROW *JBLOCKARRAY;         /* a 2-D array of coefficient blocks */
  73. typedef JBLOCKARRAY *JBLOCKIMAGE;       /* a 3-D array of coefficient blocks */
  74.  
  75. typedef JCOEF FAR *JCOEFPTR;    /* useful in a couple of places */
  76.  
  77.  
  78. /* Types for JPEG compression parameters and working tables. */
  79.  
  80.  
  81. /* DCT coefficient quantization tables. */
  82.  
  83. typedef struct {
  84.   /* This array gives the coefficient quantizers in natural array order
  85.    * (not the zigzag order in which they are stored in a JPEG DQT marker).
  86.    * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
  87.    */
  88.   UINT16 quantval[DCTSIZE2];    /* quantization step for each coefficient */
  89.   /* This field is used only during compression.  It's initialized FALSE when
  90.    * the table is created, and set TRUE when it's been output to the file.
  91.    * You could suppress output of a table by setting this to TRUE.
  92.    * (See jpeg_suppress_tables for an example.)
  93.    */
  94.   boolean sent_table;           /* TRUE when table has been output */
  95. } JQUANT_TBL;
  96.  
  97.  
  98. /* Huffman coding tables. */
  99.  
  100. typedef struct {
  101.   /* These two fields directly represent the contents of a JPEG DHT marker */
  102.   UINT8 bits[17];               /* bits[k] = # of symbols with codes of */
  103.                                 /* length k bits; bits[0] is unused */
  104.   UINT8 huffval[256];           /* The symbols, in order of incr code length */
  105.   /* This field is used only during compression.  It's initialized FALSE when
  106.    * the table is created, and set TRUE when it's been output to the file.
  107.    * You could suppress output of a table by setting this to TRUE.
  108.    * (See jpeg_suppress_tables for an example.)
  109.    */
  110.   boolean sent_table;           /* TRUE when table has been output */
  111. } JHUFF_TBL;
  112.  
  113.  
  114. /* Basic info about one component (color channel). */
  115.  
  116. typedef struct {
  117.   /* These values are fixed over the whole image. */
  118.   /* For compression, they must be supplied by parameter setup; */
  119.   /* for decompression, they are read from the SOF marker. */
  120.   int component_id;             /* identifier for this component (0..255) */
  121.   int component_index;          /* its index in SOF or cinfo->comp_info[] */
  122.   int h_samp_factor;            /* horizontal sampling factor (1..4) */
  123.   int v_samp_factor;            /* vertical sampling factor (1..4) */
  124.   int quant_tbl_no;             /* quantization table selector (0..3) */
  125.   /* These values may vary between scans. */
  126.   /* For compression, they must be supplied by parameter setup; */
  127.   /* for decompression, they are read from the SOS marker. */
  128.   /* The decompressor output side may not use these variables. */
  129.   int dc_tbl_no;                /* DC entropy table selector (0..3) */
  130.   int ac_tbl_no;                /* AC entropy table selector (0..3) */
  131.  
  132.   /* Remaining fields should be treated as private by applications. */
  133.  
  134.   /* These values are computed during compression or decompression startup: */
  135.   /* Component's size in DCT blocks.
  136.    * Any dummy blocks added to complete an MCU are not counted; therefore
  137.    * these values do not depend on whether a scan is interleaved or not.
  138.    */
  139.   JDIMENSION width_in_blocks;
  140.   JDIMENSION height_in_blocks;
  141.   /* Size of a DCT block in samples.  Always DCTSIZE for compression.
  142.    * For decompression this is the size of the output from one DCT block,
  143.    * reflecting any scaling we choose to apply during the IDCT step.
  144.    * Values of 1,2,4,8 are likely to be supported.  Note that different
  145.    * components may receive different IDCT scalings.
  146.    */
  147.   int DCT_scaled_size;
  148.   /* The downsampled dimensions are the component's actual, unpadded number
  149.    * of samples at the main buffer (preprocessing/compression interface), thus
  150.    * downsampled_width = ceil(image_width * Hi/Hmax)
  151.    * and similarly for height.  For decompression, IDCT scaling is included, so
  152.    * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)
  153.    */
  154.   JDIMENSION downsampled_width;  /* actual width in samples */
  155.   JDIMENSION downsampled_height; /* actual height in samples */
  156.   /* This flag is used only for decompression.  In cases where some of the
  157.    * components will be ignored (eg grayscale output from YCbCr image),
  158.    * we can skip most computations for the unused components.
  159.    */
  160.   boolean component_needed;     /* do we need the value of this component? */
  161.  
  162.   /* These values are computed before starting a scan of the component. */
  163.   /* The decompressor output side may not use these variables. */
  164.   int MCU_width;                /* number of blocks per MCU, horizontally */
  165.   int MCU_height;               /* number of blocks per MCU, vertically */
  166.   int MCU_blocks;               /* MCU_width * MCU_height */
  167.   int MCU_sample_width;         /* MCU width in samples, MCU_width*DCT_scaled_size */
  168.   int last_col_width;           /* # of non-dummy blocks across in last MCU */
  169.   int last_row_height;          /* # of non-dummy blocks down in last MCU */
  170.  
  171.   /* Saved quantization table for component; NULL if none yet saved.
  172.    * See jdinput.c comments about the need for this information.
  173.    * This field is currently used only for decompression.
  174.    */
  175.   JQUANT_TBL * quant_table;
  176.  
  177.   /* Private per-component storage for DCT or IDCT subsystem. */
  178.   void * dct_table;
  179. } jpeg_component_info;
  180.  
  181.  
  182. /* The script for encoding a multiple-scan file is an array of these: */
  183.  
  184. typedef struct {
  185.   int comps_in_scan;            /* number of components encoded in this scan */
  186.   int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
  187.   int Ss, Se;                   /* progressive JPEG spectral selection parms */
  188.   int Ah, Al;                   /* progressive JPEG successive approx. parms */
  189. } jpeg_scan_info;
  190.  
  191. /* The decompressor can save APPn and COM markers in a list of these: */
  192.  
  193. typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
  194.  
  195. struct jpeg_marker_struct {
  196.   jpeg_saved_marker_ptr next;   /* next in list, or NULL */
  197.   UINT8 marker;                 /* marker code: JPEG_COM, or JPEG_APP0+n */
  198.   unsigned int original_length; /* # bytes of data in the file */
  199.   unsigned int data_length;     /* # bytes of data saved at data[] */
  200.   JOCTET FAR * data;            /* the data contained in the marker */
  201.   /* the marker length word is not counted in data_length or original_length */
  202. };
  203.  
  204. /* Known color spaces. */
  205.  
  206. typedef enum {
  207.         JCS_UNKNOWN,            /* error/unspecified */
  208.         JCS_GRAYSCALE,          /* monochrome */
  209.         JCS_RGB,                /* red/green/blue */
  210.         JCS_YCbCr,              /* Y/Cb/Cr (also known as YUV) */
  211.         JCS_CMYK,               /* C/M/Y/K */
  212.         JCS_YCCK                /* Y/Cb/Cr/K */
  213. } J_COLOR_SPACE;
  214.  
  215. /* DCT/IDCT algorithm options. */
  216.  
  217. typedef enum {
  218.         JDCT_ISLOW,             /* slow but accurate integer algorithm */
  219.         JDCT_IFAST,             /* faster, less accurate integer method */
  220.         JDCT_FLOAT              /* floating-point: accurate, fast on fast HW */
  221. } J_DCT_METHOD;
  222.  
  223. #ifndef JDCT_DEFAULT            /* may be overridden in jconfig.h */
  224. #define JDCT_DEFAULT  JDCT_ISLOW
  225. #endif
  226. #ifndef JDCT_FASTEST            /* may be overridden in jconfig.h */
  227. #define JDCT_FASTEST  JDCT_IFAST
  228. #endif
  229.  
  230. /* Dithering options for decompression. */
  231.  
  232. typedef enum {
  233.         JDITHER_NONE,           /* no dithering */
  234.         JDITHER_ORDERED,        /* simple ordered dither */
  235.         JDITHER_FS              /* Floyd-Steinberg error diffusion dither */
  236. } J_DITHER_MODE;
  237.  
  238.  
  239. /* Common fields between JPEG compression and decompression master structs. */
  240.  
  241. #define jpeg_common_fields \
  242.   struct jpeg_error_mgr * err;  /* Error handler module */\
  243.   struct jpeg_memory_mgr * mem; /* Memory manager module */\
  244.   struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
  245.   void * client_data;           /* Available for use by application */\
  246.   boolean is_decompressor;      /* So common code can tell which is which */\
  247.   int global_state              /* For checking call sequence validity */
  248.  
  249. /* Routines that are to be used by both halves of the library are declared
  250.  * to receive a pointer to this structure.  There are no actual instances of
  251.  * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
  252.  */
  253. struct jpeg_common_struct {
  254.   jpeg_common_fields;           /* Fields common to both master struct types */
  255.   /* Additional fields follow in an actual jpeg_compress_struct or
  256.    * jpeg_decompress_struct.  All three structs must agree on these
  257.    * initial fields!  (This would be a lot cleaner in C++.)
  258.    */
  259. };
  260.  
  261. typedef struct jpeg_common_struct * j_common_ptr;
  262. typedef struct jpeg_compress_struct * j_compress_ptr;
  263. typedef struct jpeg_decompress_struct * j_decompress_ptr;
  264.  
  265.  
  266. /* Master record for a compression instance */
  267.  
  268. struct jpeg_compress_struct {
  269.   jpeg_common_fields;           /* Fields shared with jpeg_decompress_struct */
  270.  
  271.   /* Destination for compressed data */
  272.   struct jpeg_destination_mgr * dest;
  273.  
  274.   /* Description of source image --- these fields must be filled in by
  275.    * outer application before starting compression.  in_color_space must
  276.    * be correct before you can even call jpeg_set_defaults().
  277.    */
  278.  
  279.   JDIMENSION image_width;       /* input image width */
  280.   JDIMENSION image_height;      /* input image height */
  281.   int input_components;         /* # of color components in input image */
  282.   J_COLOR_SPACE in_color_space; /* colorspace of input image */
  283.  
  284.   double input_gamma;           /* image gamma of input image */
  285.  
  286.   /* Compression parameters --- these fields must be set before calling
  287.    * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to
  288.    * initialize everything to reasonable defaults, then changing anything
  289.    * the application specifically wants to change.  That way you won't get
  290.    * burnt when new parameters are added.  Also note that there are several
  291.    * helper routines to simplify changing parameters.
  292.    */
  293.  
  294.   int data_precision;           /* bits of precision in image data */
  295.  
  296.   int num_components;           /* # of color components in JPEG image */
  297.   J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
  298.  
  299.   jpeg_component_info * comp_info;
  300.   /* comp_info[i] describes component that appears i'th in SOF */
  301.  
  302.   JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
  303.   /* ptrs to coefficient quantization tables, or NULL if not defined */
  304.  
  305.   JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
  306.   JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
  307.   /* ptrs to Huffman coding tables, or NULL if not defined */
  308.  
  309.   UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
  310.   UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
  311.   UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
  312.  
  313.   int num_scans;                /* # of entries in scan_info array */
  314.   const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
  315.   /* The default value of scan_info is NULL, which causes a single-scan
  316.    * sequential JPEG file to be emitted.  To create a multi-scan file,
  317.    * set num_scans and scan_info to point to an array of scan definitions.
  318.    */
  319.  
  320.   boolean raw_data_in;          /* TRUE=caller supplies downsampled data */
  321.   boolean arith_code;           /* TRUE=arithmetic coding, FALSE=Huffman */
  322.   boolean optimize_coding;      /* TRUE=optimize entropy encoding parms */
  323.   boolean CCIR601_sampling;     /* TRUE=first samples are cosited */
  324.   int smoothing_factor;         /* 1..100, or 0 for no input smoothing */
  325.   J_DCT_METHOD dct_method;      /* DCT algorithm selector */
  326.  
  327.   /* The restart interval can be specified in absolute MCUs by setting
  328.    * restart_interval, or in MCU rows by setting restart_in_rows
  329.    * (in which case the correct restart_interval will be figured
  330.    * for each scan).
  331.    */
  332.   unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
  333.   int restart_in_rows;          /* if > 0, MCU rows per restart interval */
  334.  
  335.   /* Parameters controlling emission of special markers. */
  336.  
  337.   boolean write_JFIF_header;    /* should a JFIF marker be written? */
  338.   UINT8 JFIF_major_version;     /* What to write for the JFIF version number */
  339.   UINT8 JFIF_minor_version;
  340.   /* These three values are not used by the JPEG code, merely copied */
  341.   /* into the JFIF APP0 marker.  density_unit can be 0 for unknown, */
  342.   /* 1 for dots/inch, or 2 for dots/cm.  Note that the pixel aspect */
  343.   /* ratio is defined by X_density/Y_density even when density_unit=0. */
  344.   UINT8 density_unit;           /* JFIF code for pixel size units */
  345.   UINT16 X_density;             /* Horizontal pixel density */
  346.   UINT16 Y_density;             /* Vertical pixel density */
  347.   boolean write_Adobe_marker;   /* should an Adobe marker be written? */
  348.  
  349.   /* State variable: index of next scanline to be written to
  350.    * jpeg_write_scanlines().  Application may use this to control its
  351.    * processing loop, e.g., "while (next_scanline < image_height)".
  352.    */
  353.  
  354.   JDIMENSION next_scanline;     /* 0 .. image_height-1  */
  355.  
  356.   /* Remaining fields are known throughout compressor, but generally
  357.    * should not be touched by a surrounding application.
  358.    */
  359.  
  360.   /*
  361.    * These fields are computed during compression startup
  362.    */
  363.   boolean progressive_mode;     /* TRUE if scan script uses progressive mode */
  364.   int max_h_samp_factor;        /* largest h_samp_factor */
  365.   int max_v_samp_factor;        /* largest v_samp_factor */
  366.  
  367.   JDIMENSION total_iMCU_rows;   /* # of iMCU rows to be input to coef ctlr */
  368.   /* The coefficient controller receives data in units of MCU rows as defined
  369.    * for fully interleaved scans (whether the JPEG file is interleaved or not).
  370.    * There are v_samp_factor * DCTSIZE sample rows of each component in an
  371.    * "iMCU" (interleaved MCU) row.
  372.    */
  373.  
  374.   /*
  375.    * These fields are valid during any one scan.
  376.    * They describe the components and MCUs actually appearing in the scan.
  377.    */
  378.   int comps_in_scan;            /* # of JPEG components in this scan */
  379.   jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
  380.   /* *cur_comp_info[i] describes component that appears i'th in SOS */
  381.  
  382.   JDIMENSION MCUs_per_row;      /* # of MCUs across the image */
  383.   JDIMENSION MCU_rows_in_scan;  /* # of MCU rows in the image */
  384.  
  385.   int blocks_in_MCU;            /* # of DCT blocks per MCU */
  386.   int MCU_membership[C_MAX_BLOCKS_IN_MCU];
  387.   /* MCU_membership[i] is index in cur_comp_info of component owning */
  388.   /* i'th block in an MCU */
  389.  
  390.   int Ss, Se, Ah, Al;           /* progressive JPEG parameters for scan */
  391.  
  392.   /*
  393.    * Links to compression subobjects (methods and private variables of modules)
  394.    */
  395.   struct jpeg_comp_master * master;
  396.   struct jpeg_c_main_controller * main;
  397.   struct jpeg_c_prep_controller * prep;
  398.   struct jpeg_c_coef_controller * coef;
  399.   struct jpeg_marker_writer * marker;
  400.   struct jpeg_color_converter * cconvert;
  401.   struct jpeg_downsampler * downsample;
  402.   struct jpeg_forward_dct * fdct;
  403.   struct jpeg_entropy_encoder * entropy;
  404.   jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
  405.   int script_space_size;
  406. };
  407.  
  408.  
  409. /* Master record for a decompression instance */
  410.  
  411. struct jpeg_decompress_struct {
  412.   jpeg_common_fields;           /* Fields shared with jpeg_compress_struct */
  413.  
  414.   /* Source of compressed data */
  415.   struct jpeg_source_mgr * src;
  416.  
  417.   /* Basic description of image --- filled in by jpeg_read_header(). */
  418.   /* Application may inspect these values to decide how to process image. */
  419.  
  420.   JDIMENSION image_width;       /* nominal image width (from SOF marker) */
  421.   JDIMENSION image_height;      /* nominal image height */
  422.   int num_components;           /* # of color components in JPEG image */
  423.   J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
  424.  
  425.   /* Decompression processing parameters --- these fields must be set before
  426.    * calling jpeg_start_decompress().  Note that jpeg_read_header() initializes
  427.    * them to default values.
  428.    */
  429.  
  430.   J_COLOR_SPACE out_color_space; /* colorspace for output */
  431.  
  432.   unsigned int scale_num, scale_denom; /* fraction by which to scale image */
  433.  
  434.   double output_gamma;          /* image gamma wanted in output */
  435.  
  436.   boolean buffered_image;       /* TRUE=multiple output passes */
  437.   boolean raw_data_out;         /* TRUE=downsampled data wanted */
  438.  
  439.   J_DCT_METHOD dct_method;      /* IDCT algorithm selector */
  440.   boolean do_fancy_upsampling;  /* TRUE=apply fancy upsampling */
  441.   boolean do_block_smoothing;   /* TRUE=apply interblock smoothing */
  442.  
  443.   boolean quantize_colors;      /* TRUE=colormapped output wanted */
  444.   /* the following are ignored if not quantize_colors: */
  445.   J_DITHER_MODE dither_mode;    /* type of color dithering to use */
  446.   boolean two_pass_quantize;    /* TRUE=use two-pass color quantization */
  447.   int desired_number_of_colors; /* max # colors to use in created colormap */
  448.   /* these are significant only in buffered-image mode: */
  449.   boolean enable_1pass_quant;   /* enable future use of 1-pass quantizer */
  450.   boolean enable_external_quant;/* enable future use of external colormap */
  451.   boolean enable_2pass_quant;   /* enable future use of 2-pass quantizer */
  452.  
  453.   /* Description of actual output image that will be returned to application.
  454.    * These fields are computed by jpeg_start_decompress().
  455.    * You can also use jpeg_calc_output_dimensions() to determine these values
  456.    * in advance of calling jpeg_start_decompress().
  457.    */
  458.  
  459.   JDIMENSION output_width;      /* scaled image width */
  460.   JDIMENSION output_height;     /* scaled image height */
  461.   int out_color_components;     /* # of color components in out_color_space */
  462.   int output_components;        /* # of color components returned */
  463.   /* output_components is 1 (a colormap index) when quantizing colors;
  464.    * otherwise it equals out_color_components.
  465.    */
  466.   int rec_outbuf_height;        /* min recommended height of scanline buffer */
  467.   /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
  468.    * high, space and time will be wasted due to unnecessary data copying.
  469.    * Usually rec_outbuf_height will be 1 or 2, at most 4.
  470.    */
  471.  
  472.   /* When quantizing colors, the output colormap is described by these fields.
  473.    * The application can supply a colormap by setting colormap non-NULL before
  474.    * calling jpeg_start_decompress; otherwise a colormap is created during
  475.    * jpeg_start_decompress or jpeg_start_output.
  476.    * The map has out_color_components rows and actual_number_of_colors columns.
  477.    */
  478.   int actual_number_of_colors;  /* number of entries in use */
  479.   JSAMPARRAY colormap;          /* The color map as a 2-D pixel array */
  480.  
  481.   /* State variables: these variables indicate the progress of decompression.
  482.    * The application may examine these but must not modify them.
  483.    */
  484.  
  485.   /* Row index of next scanline to be read from jpeg_read_scanlines().
  486.    * Application may use this to control its processing loop, e.g.,
  487.    * "while (output_scanline < output_height)".
  488.    */
  489.   JDIMENSION output_scanline;   /* 0 .. output_height-1  */
  490.  
  491.   /* Current input scan number and number of iMCU rows completed in scan.
  492.    * These indicate the progress of the decompressor input side.
  493.    */
  494.   int input_scan_number;        /* Number of SOS markers seen so far */
  495.   JDIMENSION input_iMCU_row;    /* Number of iMCU rows completed */
  496.  
  497.   /* The "output scan number" is the notional scan being displayed by the
  498.    * output side.  The decompressor will not allow output scan/row number
  499.    * to get ahead of input scan/row, but it can fall arbitrarily far behind.
  500.    */
  501.   int output_scan_number;       /* Nominal scan number being displayed */
  502.   JDIMENSION output_iMCU_row;   /* Number of iMCU rows read */
  503.  
  504.   /* Current progression status.  coef_bits[c][i] indicates the precision
  505.    * with which component c's DCT coefficient i (in zigzag order) is known.
  506.    * It is -1 when no data has yet been received, otherwise it is the point
  507.    * transform (shift) value for the most recent scan of the coefficient
  508.    * (thus, 0 at completion of the progression).
  509.    * This pointer is NULL when reading a non-progressive file.
  510.    */
  511.   int (*coef_bits)[DCTSIZE2];   /* -1 or current Al value for each coef */
  512.  
  513.   /* Internal JPEG parameters --- the application usually need not look at
  514.    * these fields.  Note that the decompressor output side may not use
  515.    * any parameters that can change between scans.
  516.    */
  517.  
  518.   /* Quantization and Huffman tables are carried forward across input
  519.    * datastreams when processing abbreviated JPEG datastreams.
  520.    */
  521.  
  522.   JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
  523.   /* ptrs to coefficient quantization tables, or NULL if not defined */
  524.  
  525.   JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
  526.   JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
  527.   /* ptrs to Huffman coding tables, or NULL if not defined */
  528.  
  529.   /* These parameters are never carried across datastreams, since they
  530.    * are given in SOF/SOS markers or defined to be reset by SOI.
  531.    */
  532.  
  533.   int data_precision;           /* bits of precision in image data */
  534.  
  535.   jpeg_component_info * comp_info;
  536.   /* comp_info[i] describes component that appears i'th in SOF */
  537.  
  538.   boolean progressive_mode;     /* TRUE if SOFn specifies progressive mode */
  539.   boolean arith_code;           /* TRUE=arithmetic coding, FALSE=Huffman */
  540.  
  541.   UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
  542.   UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
  543.   UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
  544.  
  545.   unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
  546.  
  547.   /* These fields record data obtained from optional markers recognized by
  548.    * the JPEG library.
  549.    */
  550.   boolean saw_JFIF_marker;      /* TRUE iff a JFIF APP0 marker was found */
  551.   /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
  552.   UINT8 JFIF_major_version;     /* JFIF version number */
  553.   UINT8 JFIF_minor_version;
  554.   UINT8 density_unit;           /* JFIF code for pixel size units */
  555.   UINT16 X_density;             /* Horizontal pixel density */
  556.   UINT16 Y_density;             /* Vertical pixel density */
  557.   boolean saw_Adobe_marker;     /* TRUE iff an Adobe APP14 marker was found */
  558.   UINT8 Adobe_transform;        /* Color transform code from Adobe marker */
  559.  
  560.   boolean CCIR601_sampling;     /* TRUE=first samples are cosited */
  561.  
  562.   /* Aside from the specific data retained from APPn markers known to the
  563.    * library, the uninterpreted contents of any or all APPn and COM markers
  564.    * can be saved in a list for examination by the application.
  565.    */
  566.   jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
  567.  
  568.   /* Remaining fields are known throughout decompressor, but generally
  569.    * should not be touched by a surrounding application.
  570.    */
  571.  
  572.   /*
  573.    * These fields are computed during decompression startup
  574.    */
  575.   int max_h_samp_factor;        /* largest h_samp_factor */
  576.   int max_v_samp_factor;        /* largest v_samp_factor */
  577.  
  578.   int min_DCT_scaled_size;      /* smallest DCT_scaled_size of any component */
  579.  
  580.   JDIMENSION total_iMCU_rows;   /* # of iMCU rows in image */
  581.   /* The coefficient controller's input and output progress is measured in
  582.    * units of "iMCU" (interleaved MCU) rows.  These are the same as MCU rows
  583.    * in fully interleaved JPEG scans, but are used whether the scan is
  584.    * interleaved or not.  We define an iMCU row as v_samp_factor DCT block
  585.    * rows of each component.  Therefore, the IDCT output contains
  586.    * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
  587.    */
  588.  
  589.   JSAMPLE * sample_range_limit; /* table for fast range-limiting */
  590.  
  591.   /*
  592.    * These fields are valid during any one scan.
  593.    * They describe the components and MCUs actually appearing in the scan.
  594.    * Note that the decompressor output side must not use these fields.
  595.    */
  596.   int comps_in_scan;            /* # of JPEG components in this scan */
  597.   jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
  598.   /* *cur_comp_info[i] describes component that appears i'th in SOS */
  599.  
  600.   JDIMENSION MCUs_per_row;      /* # of MCUs across the image */
  601.   JDIMENSION MCU_rows_in_scan;  /* # of MCU rows in the image */
  602.  
  603.   int blocks_in_MCU;            /* # of DCT blocks per MCU */
  604.   int MCU_membership[D_MAX_BLOCKS_IN_MCU];
  605.   /* MCU_membership[i] is index in cur_comp_info of component owning */
  606.   /* i'th block in an MCU */
  607.  
  608.   int Ss, Se, Ah, Al;           /* progressive JPEG parameters for scan */
  609.  
  610.   /* This field is shared between entropy decoder and marker parser.
  611.    * It is either zero or the code of a JPEG marker that has been
  612.    * read from the data source, but has not yet been processed.
  613.    */
  614.   int unread_marker;
  615.  
  616.   /*
  617.    * Links to decompression subobjects (methods, private variables of modules)
  618.    */
  619.   struct jpeg_decomp_master * master;
  620.   struct jpeg_d_main_controller * main;
  621.   struct jpeg_d_coef_controller * coef;
  622.   struct jpeg_d_post_controller * post;
  623.   struct jpeg_input_controller * inputctl;
  624.   struct jpeg_marker_reader * marker;
  625.   struct jpeg_entropy_decoder * entropy;
  626.   struct jpeg_inverse_dct * idct;
  627.   struct jpeg_upsampler * upsample;
  628.   struct jpeg_color_deconverter * cconvert;
  629.   struct jpeg_color_quantizer * cquantize;
  630. };
  631.  
  632.  
  633. /* "Object" declarations for JPEG modules that may be supplied or called
  634.  * directly by the surrounding application.
  635.  * As with all objects in the JPEG library, these structs only define the
  636.  * publicly visible methods and state variables of a module.  Additional
  637.  * private fields may exist after the public ones.
  638.  */
  639.  
  640.  
  641. /* Error handler object */
  642.  
  643. struct jpeg_error_mgr {
  644.   /* Error exit handler: does not return to caller */
  645.   JMETHOD(void, error_exit, (j_common_ptr cinfo));
  646.   /* Conditionally emit a trace or warning message */
  647.   JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
  648.   /* Routine that actually outputs a trace or error message */
  649.   JMETHOD(void, output_message, (j_common_ptr cinfo));
  650.   /* Format a message string for the most recent JPEG error or message */
  651.   JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
  652. #define JMSG_LENGTH_MAX  200    /* recommended size of format_message buffer */
  653.   /* Reset error state variables at start of a new image */
  654.   JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
  655.  
  656.   /* The message ID code and any parameters are saved here.
  657.    * A message can have one string parameter or up to 8 int parameters.
  658.    */
  659.   int msg_code;
  660. #define JMSG_STR_PARM_MAX  80
  661.   union {
  662.     int i[8];
  663.     char s[JMSG_STR_PARM_MAX];
  664.   } msg_parm;
  665.  
  666.   /* Standard state variables for error facility */
  667.  
  668.   int trace_level;              /* max msg_level that will be displayed */
  669.  
  670.   /* For recoverable corrupt-data errors, we emit a warning message,
  671.    * but keep going unless emit_message chooses to abort.  emit_message
  672.    * should count warnings in num_warnings.  The surrounding application
  673.    * can check for bad data by seeing if num_warnings is nonzero at the
  674.    * end of processing.
  675.    */
  676.   long num_warnings;            /* number of corrupt-data warnings */
  677.  
  678.   /* These fields point to the table(s) of error message strings.
  679.    * An application can change the table pointer to switch to a different
  680.    * message list (typically, to change the language in which errors are
  681.    * reported).  Some applications may wish to add additional error codes
  682.    * that will be handled by the JPEG library error mechanism; the second
  683.    * table pointer is used for this purpose.
  684.    *
  685.    * First table includes all errors generated by JPEG library itself.
  686.    * Error code 0 is reserved for a "no such error string" message.
  687.    */
  688.   const char * const * jpeg_message_table; /* Library errors */
  689.   int last_jpeg_message;    /* Table contains strings 0..last_jpeg_message */
  690.   /* Second table can be added by application (see cjpeg/djpeg for example).
  691.    * It contains strings numbered first_addon_message..last_addon_message.
  692.    */
  693.   const char * const * addon_message_table; /* Non-library errors */
  694.   int first_addon_message;      /* code for first string in addon table */
  695.   int last_addon_message;       /* code for last string in addon table */
  696. };
  697.  
  698.  
  699. /* Progress monitor object */
  700.  
  701. struct jpeg_progress_mgr {
  702.   JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
  703.  
  704.   long pass_counter;            /* work units completed in this pass */
  705.   long pass_limit;              /* total number of work units in this pass */
  706.   int completed_passes;         /* passes completed so far */
  707.   int total_passes;             /* total number of passes expected */
  708. };
  709.  
  710.  
  711. /* Data destination object for compression */
  712.  
  713. struct jpeg_destination_mgr {
  714.   JOCTET * next_output_byte;    /* => next byte to write in buffer */
  715.   size_t free_in_buffer;        /* # of byte spaces remaining in buffer */
  716.  
  717.   JMETHOD(void, init_destination, (j_compress_ptr cinfo));
  718.   JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
  719.   JMETHOD(void, term_destination, (j_compress_ptr cinfo));
  720. };
  721.  
  722.  
  723. /* Data source object for decompression */
  724.  
  725. struct jpeg_source_mgr {
  726.   const JOCTET * next_input_byte; /* => next byte to read from buffer */
  727.   size_t bytes_in_buffer;       /* # of bytes remaining in buffer */
  728.  
  729.   JMETHOD(void, init_source, (j_decompress_ptr cinfo));
  730.   JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
  731.   JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
  732.   JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
  733.   JMETHOD(void, term_source, (j_decompress_ptr cinfo));
  734. };
  735.  
  736.  
  737. /* Memory manager object.
  738.  * Allocates "small" objects (a few K total), "large" objects (tens of K),
  739.  * and "really big" objects (virtual arrays with backing store if needed).
  740.  * The memory manager does not allow individual objects to be freed; rather,
  741.  * each created object is assigned to a pool, and whole pools can be freed
  742.  * at once.  This is faster and more convenient than remembering exactly what
  743.  * to free, especially where malloc()/free() are not too speedy.
  744.  * NB: alloc routines never return NULL.  They exit to error_exit if not
  745.  * successful.
  746.  */
  747.  
  748. #define JPOOL_PERMANENT 0       /* lasts until master record is destroyed */
  749. #define JPOOL_IMAGE     1       /* lasts until done with image/datastream */
  750. #define JPOOL_NUMPOOLS  2
  751.  
  752. typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
  753. typedef struct jvirt_barray_control * jvirt_barray_ptr;
  754.  
  755.  
  756. struct jpeg_memory_mgr {
  757.   /* Method pointers */
  758.   JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
  759.                                 size_t sizeofobject));
  760.   JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
  761.                                      size_t sizeofobject));
  762.   JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
  763.                                      JDIMENSION samplesperrow,
  764.                                      JDIMENSION numrows));
  765.   JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
  766.                                       JDIMENSION blocksperrow,
  767.                                       JDIMENSION numrows));
  768.   JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
  769.                                                   int pool_id,
  770.                                                   boolean pre_zero,
  771.                                                   JDIMENSION samplesperrow,
  772.                                                   JDIMENSION numrows,
  773.                                                   JDIMENSION maxaccess));
  774.   JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
  775.                                                   int pool_id,
  776.                                                   boolean pre_zero,
  777.                                                   JDIMENSION blocksperrow,
  778.                                                   JDIMENSION numrows,
  779.                                                   JDIMENSION maxaccess));
  780.   JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
  781.   JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
  782.                                            jvirt_sarray_ptr ptr,
  783.                                            JDIMENSION start_row,
  784.                                            JDIMENSION num_rows,
  785.                                            boolean writable));
  786.   JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
  787.                                             jvirt_barray_ptr ptr,
  788.                                             JDIMENSION start_row,
  789.                                             JDIMENSION num_rows,
  790.                                             boolean writable));
  791.   JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
  792.   JMETHOD(void, self_destruct, (j_common_ptr cinfo));
  793.  
  794.   /* Limit on memory allocation for this JPEG object.  (Note that this is
  795.    * merely advisory, not a guaranteed maximum; it only affects the space
  796.    * used for virtual-array buffers.)  May be changed by outer application
  797.    * after creating the JPEG object.
  798.    */
  799.   long max_memory_to_use;
  800.  
  801.   /* Maximum allocation request accepted by alloc_large. */
  802.   long max_alloc_chunk;
  803. };
  804.  
  805.  
  806. /* Routine signature for application-supplied marker processing methods.
  807.  * Need not pass marker code since it is stored in cinfo->unread_marker.
  808.  */
  809. typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
  810.  
  811.  
  812. /* Declarations for routines called by application.
  813.  * The JPP macro hides prototype parameters from compilers that can't cope.
  814.  * Note JPP requires double parentheses.
  815.  */
  816.  
  817. #ifdef HAVE_PROTOTYPES
  818. #define JPP(arglist)    arglist
  819. #else
  820. #define JPP(arglist)    ()
  821. #endif
  822.  
  823.  
  824. /* Short forms of external names for systems with brain-damaged linkers.
  825.  * We shorten external names to be unique in the first six letters, which
  826.  * is good enough for all known systems.
  827.  * (If your compiler itself needs names to be unique in less than 15
  828.  * characters, you are out of luck.  Get a better compiler.)
  829.  */
  830.  
  831. #ifdef NEED_SHORT_EXTERNAL_NAMES
  832. #define jpeg_std_error          jStdError
  833. #define jpeg_CreateCompress     jCreaCompress
  834. #define jpeg_CreateDecompress   jCreaDecompress
  835. #define jpeg_destroy_compress   jDestCompress
  836. #define jpeg_destroy_decompress jDestDecompress
  837. #define jpeg_stdio_dest         jStdDest
  838. #define jpeg_stdio_src          jStdSrc
  839. #define jpeg_set_defaults       jSetDefaults
  840. #define jpeg_set_colorspace     jSetColorspace
  841. #define jpeg_default_colorspace jDefColorspace
  842. #define jpeg_set_quality        jSetQuality
  843. #define jpeg_set_linear_quality jSetLQuality
  844. #define jpeg_add_quant_table    jAddQuantTable
  845. #define jpeg_quality_scaling    jQualityScaling
  846. #define jpeg_simple_progression jSimProgress
  847. #define jpeg_suppress_tables    jSuppressTables
  848. #define jpeg_alloc_quant_table  jAlcQTable
  849. #define jpeg_alloc_huff_table   jAlcHTable
  850. #define jpeg_start_compress     jStrtCompress
  851. #define jpeg_write_scanlines    jWrtScanlines
  852. #define jpeg_finish_compress    jFinCompress
  853. #define jpeg_write_raw_data     jWrtRawData
  854. #define jpeg_write_marker       jWrtMarker
  855. #define jpeg_write_m_header     jWrtMHeader
  856. #define jpeg_write_m_byte       jWrtMByte
  857. #define jpeg_write_tables       jWrtTables
  858. #define jpeg_read_header        jReadHeader
  859. #define jpeg_start_decompress   jStrtDecompress
  860. #define jpeg_read_scanlines     jReadScanlines
  861. #define jpeg_finish_decompress  jFinDecompress
  862. #define jpeg_read_raw_data      jReadRawData
  863. #define jpeg_has_multiple_scans jHasMultScn
  864. #define jpeg_start_output       jStrtOutput
  865. #define jpeg_finish_output      jFinOutput
  866. #define jpeg_input_complete     jInComplete
  867. #define jpeg_new_colormap       jNewCMap
  868. #define jpeg_consume_input      jConsumeInput
  869. #define jpeg_calc_output_dimensions     jCalcDimensions
  870. #define jpeg_save_markers       jSaveMarkers
  871. #define jpeg_set_marker_processor       jSetMarker
  872. #define jpeg_read_coefficients  jReadCoefs
  873. #define jpeg_write_coefficients jWrtCoefs
  874. #define jpeg_copy_critical_parameters   jCopyCrit
  875. #define jpeg_abort_compress     jAbrtCompress
  876. #define jpeg_abort_decompress   jAbrtDecompress
  877. #define jpeg_abort              jAbort
  878. #define jpeg_destroy            jDestroy
  879. #define jpeg_resync_to_restart  jResyncRestart
  880. #endif /* NEED_SHORT_EXTERNAL_NAMES */
  881.  
  882.  
  883. /* Default error-management setup */
  884. EXTERN(struct jpeg_error_mgr *) jpeg_std_error
  885.         JPP((struct jpeg_error_mgr * err));
  886.  
  887. /* Initialization of JPEG compression objects.
  888.  * jpeg_create_compress() and jpeg_create_decompress() are the exported
  889.  * names that applications should call.  These expand to calls on
  890.  * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
  891.  * passed for version mismatch checking.
  892.  * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
  893.  */
  894. #define jpeg_create_compress(cinfo) \
  895.     jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
  896.                         (size_t) sizeof(struct jpeg_compress_struct))
  897. #define jpeg_create_decompress(cinfo) \
  898.     jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
  899.                           (size_t) sizeof(struct jpeg_decompress_struct))
  900. EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
  901.                                       int version, size_t structsize));
  902. EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
  903.                                         int version, size_t structsize));
  904. /* Destruction of JPEG compression objects */
  905. EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
  906. EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
  907.  
  908. /* Standard data source and destination managers: stdio streams. */
  909. /* Caller is responsible for opening the file before and closing after. */
  910. EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
  911. EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
  912.  
  913. /* Default parameter setup for compression */
  914. EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
  915. /* Compression parameter setup aids */
  916. EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
  917.                                       J_COLOR_SPACE colorspace));
  918. EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
  919. EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
  920.                                    boolean force_baseline));
  921. EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
  922.                                           int scale_factor,
  923.                                           boolean force_baseline));
  924. EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
  925.                                        const unsigned int *basic_table,
  926.                                        int scale_factor,
  927.                                        boolean force_baseline));
  928. EXTERN(int) jpeg_quality_scaling JPP((int quality));
  929. EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
  930. EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
  931.                                        boolean suppress));
  932. EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
  933. EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
  934.  
  935. /* Main entry points for compression */
  936. EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
  937.                                       boolean write_all_tables));
  938. EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
  939.                                              JSAMPARRAY scanlines,
  940.                                              JDIMENSION num_lines));
  941. EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
  942.  
  943. /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
  944. EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
  945.                                             JSAMPIMAGE data,
  946.                                             JDIMENSION num_lines));
  947.  
  948. /* Write a special marker.  See libjpeg.doc concerning safe usage. */
  949. EXTERN(void) jpeg_write_marker
  950.         JPP((j_compress_ptr cinfo, int marker,
  951.              const JOCTET * dataptr, unsigned int datalen));
  952. /* Same, but piecemeal. */
  953. EXTERN(void) jpeg_write_m_header
  954.         JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
  955. EXTERN(void) jpeg_write_m_byte
  956.         JPP((j_compress_ptr cinfo, int val));
  957.  
  958. /* Alternate compression function: just write an abbreviated table file */
  959. EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
  960.  
  961. /* Decompression startup: read start of JPEG datastream to see what's there */
  962. EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
  963.                                   boolean require_image));
  964. /* Return value is one of: */
  965. #define JPEG_SUSPENDED          0 /* Suspended due to lack of input data */
  966. #define JPEG_HEADER_OK          1 /* Found valid image datastream */
  967. #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
  968. /* If you pass require_image = TRUE (normal case), you need not check for
  969.  * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
  970.  * JPEG_SUSPENDED is only possible if you use a data source module that can
  971.  * give a suspension return (the stdio source module doesn't).
  972.  */
  973.  
  974. /* Main entry points for decompression */
  975. EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
  976. EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
  977.                                             JSAMPARRAY scanlines,
  978.                                             JDIMENSION max_lines));
  979. EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
  980.  
  981. /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
  982. EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
  983.                                            JSAMPIMAGE data,
  984.                                            JDIMENSION max_lines));
  985.  
  986. /* Additional entry points for buffered-image mode. */
  987. EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
  988. EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
  989.                                        int scan_number));
  990. EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
  991. EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
  992. EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
  993. EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
  994. /* Return value is one of: */
  995. /* #define JPEG_SUSPENDED       0    Suspended due to lack of input data */
  996. #define JPEG_REACHED_SOS        1 /* Reached start of new scan */
  997. #define JPEG_REACHED_EOI        2 /* Reached end of image */
  998. #define JPEG_ROW_COMPLETED      3 /* Completed one iMCU row */
  999. #define JPEG_SCAN_COMPLETED     4 /* Completed last iMCU row of a scan */
  1000.  
  1001. /* Precalculate output dimensions for current decompression parameters. */
  1002. EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
  1003.  
  1004. /* Control saving of COM and APPn markers into marker_list. */
  1005. EXTERN(void) jpeg_save_markers
  1006.         JPP((j_decompress_ptr cinfo, int marker_code,
  1007.              unsigned int length_limit));
  1008.  
  1009. /* Install a special processing method for COM or APPn markers. */
  1010. EXTERN(void) jpeg_set_marker_processor
  1011.         JPP((j_decompress_ptr cinfo, int marker_code,
  1012.              jpeg_marker_parser_method routine));
  1013.  
  1014. /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
  1015. EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
  1016. EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
  1017.                                           jvirt_barray_ptr * coef_arrays));
  1018. EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
  1019.                                                 j_compress_ptr dstinfo));
  1020.  
  1021. /* If you choose to abort compression or decompression before completing
  1022.  * jpeg_finish_(de)compress, then you need to clean up to release memory,
  1023.  * temporary files, etc.  You can just call jpeg_destroy_(de)compress
  1024.  * if you're done with the JPEG object, but if you want to clean it up and
  1025.  * reuse it, call this:
  1026.  */
  1027. EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
  1028. EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
  1029.  
  1030. /* Generic versions of jpeg_abort and jpeg_destroy that work on either
  1031.  * flavor of JPEG object.  These may be more convenient in some places.
  1032.  */
  1033. EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
  1034. EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
  1035.  
  1036. /* Default restart-marker-resync procedure for use by data source modules */
  1037. EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
  1038.                                             int desired));
  1039.  
  1040.  
  1041. /* These marker codes are exported since applications and data source modules
  1042.  * are likely to want to use them.
  1043.  */
  1044.  
  1045. #define JPEG_RST0       0xD0    /* RST0 marker code */
  1046. #define JPEG_EOI        0xD9    /* EOI marker code */
  1047. #define JPEG_APP0       0xE0    /* APP0 marker code */
  1048. #define JPEG_COM        0xFE    /* COM marker code */
  1049.  
  1050.  
  1051. /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
  1052.  * for structure definitions that are never filled in, keep it quiet by
  1053.  * supplying dummy definitions for the various substructures.
  1054.  */
  1055.  
  1056. #ifdef INCOMPLETE_TYPES_BROKEN
  1057. #ifndef JPEG_INTERNALS          /* will be defined in jpegint.h */
  1058. struct jvirt_sarray_control { long dummy; };
  1059. struct jvirt_barray_control { long dummy; };
  1060. struct jpeg_comp_master { long dummy; };
  1061. struct jpeg_c_main_controller { long dummy; };
  1062. struct jpeg_c_prep_controller { long dummy; };
  1063. struct jpeg_c_coef_controller { long dummy; };
  1064. struct jpeg_marker_writer { long dummy; };
  1065. struct jpeg_color_converter { long dummy; };
  1066. struct jpeg_downsampler { long dummy; };
  1067. struct jpeg_forward_dct { long dummy; };
  1068. struct jpeg_entropy_encoder { long dummy; };
  1069. struct jpeg_decomp_master { long dummy; };
  1070. struct jpeg_d_main_controller { long dummy; };
  1071. struct jpeg_d_coef_controller { long dummy; };
  1072. struct jpeg_d_post_controller { long dummy; };
  1073. struct jpeg_input_controller { long dummy; };
  1074. struct jpeg_marker_reader { long dummy; };
  1075. struct jpeg_entropy_decoder { long dummy; };
  1076. struct jpeg_inverse_dct { long dummy; };
  1077. struct jpeg_upsampler { long dummy; };
  1078. struct jpeg_color_deconverter { long dummy; };
  1079. struct jpeg_color_quantizer { long dummy; };
  1080. #endif /* JPEG_INTERNALS */
  1081. #endif /* INCOMPLETE_TYPES_BROKEN */
  1082.  
  1083.  
  1084. /*
  1085.  * The JPEG library modules define JPEG_INTERNALS before including this file.
  1086.  * The internal structure declarations are read only when that is true.
  1087.  * Applications using the library should not include jpegint.h, but may wish
  1088.  * to include jerror.h.
  1089.  */
  1090.  
  1091. #ifdef JPEG_INTERNALS
  1092. #include "jpegint.h"            /* fetch private declarations */
  1093. #include "jerror.h"             /* fetch error codes too */
  1094. #endif
  1095.  
  1096. #endif /* JPEGLIB_H */
  1097.