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/src/FreeImage/Source/LibJPEG/jpeglib.h

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   1/*
   2 * jpeglib.h
   3 *
   4 * Copyright (C) 1991-1998, Thomas G. Lane.
   5 * Modified 2002-2011 by Guido Vollbeding.
   6 * This file is part of the Independent JPEG Group's software.
   7 * For conditions of distribution and use, see the accompanying README file.
   8 *
   9 * This file defines the application interface for the JPEG library.
  10 * Most applications using the library need only include this file,
  11 * and perhaps jerror.h if they want to know the exact error codes.
  12 */
  13
  14#ifndef JPEGLIB_H
  15#define JPEGLIB_H
  16
  17/*
  18 * First we include the configuration files that record how this
  19 * installation of the JPEG library is set up.  jconfig.h can be
  20 * generated automatically for many systems.  jmorecfg.h contains
  21 * manual configuration options that most people need not worry about.
  22 */
  23
  24#ifndef JCONFIG_INCLUDED	/* in case jinclude.h already did */
  25#include "jconfig.h"		/* widely used configuration options */
  26#endif
  27#include "jmorecfg.h"		/* seldom changed options */
  28
  29
  30#ifdef __cplusplus
  31#ifndef DONT_USE_EXTERN_C
  32extern "C" {
  33#endif
  34#endif
  35
  36/* Version IDs for the JPEG library.
  37 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 80".
  38 */
  39
  40#define JPEG_LIB_VERSION        80	/* Compatibility version 8.0 */
  41#define JPEG_LIB_VERSION_MAJOR  8
  42#define JPEG_LIB_VERSION_MINOR  4
  43
  44
  45/* Various constants determining the sizes of things.
  46 * All of these are specified by the JPEG standard, so don't change them
  47 * if you want to be compatible.
  48 */
  49
  50#define DCTSIZE		    8	/* The basic DCT block is 8x8 coefficients */
  51#define DCTSIZE2	    64	/* DCTSIZE squared; # of elements in a block */
  52#define NUM_QUANT_TBLS      4	/* Quantization tables are numbered 0..3 */
  53#define NUM_HUFF_TBLS       4	/* Huffman tables are numbered 0..3 */
  54#define NUM_ARITH_TBLS      16	/* Arith-coding tables are numbered 0..15 */
  55#define MAX_COMPS_IN_SCAN   4	/* JPEG limit on # of components in one scan */
  56#define MAX_SAMP_FACTOR     4	/* JPEG limit on sampling factors */
  57/* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
  58 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
  59 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
  60 * to handle it.  We even let you do this from the jconfig.h file.  However,
  61 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
  62 * sometimes emits noncompliant files doesn't mean you should too.
  63 */
  64#define C_MAX_BLOCKS_IN_MCU   10 /* compressor's limit on blocks per MCU */
  65#ifndef D_MAX_BLOCKS_IN_MCU
  66#define D_MAX_BLOCKS_IN_MCU   10 /* decompressor's limit on blocks per MCU */
  67#endif
  68
  69
  70/* Data structures for images (arrays of samples and of DCT coefficients).
  71 * On 80x86 machines, the image arrays are too big for near pointers,
  72 * but the pointer arrays can fit in near memory.
  73 */
  74
  75typedef JSAMPLE FAR *JSAMPROW;	/* ptr to one image row of pixel samples. */
  76typedef JSAMPROW *JSAMPARRAY;	/* ptr to some rows (a 2-D sample array) */
  77typedef JSAMPARRAY *JSAMPIMAGE;	/* a 3-D sample array: top index is color */
  78
  79typedef JCOEF JBLOCK[DCTSIZE2];	/* one block of coefficients */
  80typedef JBLOCK FAR *JBLOCKROW;	/* pointer to one row of coefficient blocks */
  81typedef JBLOCKROW *JBLOCKARRAY;		/* a 2-D array of coefficient blocks */
  82typedef JBLOCKARRAY *JBLOCKIMAGE;	/* a 3-D array of coefficient blocks */
  83
  84typedef JCOEF FAR *JCOEFPTR;	/* useful in a couple of places */
  85
  86
  87/* Types for JPEG compression parameters and working tables. */
  88
  89
  90/* DCT coefficient quantization tables. */
  91
  92typedef struct {
  93  /* This array gives the coefficient quantizers in natural array order
  94   * (not the zigzag order in which they are stored in a JPEG DQT marker).
  95   * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
  96   */
  97  UINT16 quantval[DCTSIZE2];	/* quantization step for each coefficient */
  98  /* This field is used only during compression.  It's initialized FALSE when
  99   * the table is created, and set TRUE when it's been output to the file.
 100   * You could suppress output of a table by setting this to TRUE.
 101   * (See jpeg_suppress_tables for an example.)
 102   */
 103  boolean sent_table;		/* TRUE when table has been output */
 104} JQUANT_TBL;
 105
 106
 107/* Huffman coding tables. */
 108
 109typedef struct {
 110  /* These two fields directly represent the contents of a JPEG DHT marker */
 111  UINT8 bits[17];		/* bits[k] = # of symbols with codes of */
 112				/* length k bits; bits[0] is unused */
 113  UINT8 huffval[256];		/* The symbols, in order of incr code length */
 114  /* This field is used only during compression.  It's initialized FALSE when
 115   * the table is created, and set TRUE when it's been output to the file.
 116   * You could suppress output of a table by setting this to TRUE.
 117   * (See jpeg_suppress_tables for an example.)
 118   */
 119  boolean sent_table;		/* TRUE when table has been output */
 120} JHUFF_TBL;
 121
 122
 123/* Basic info about one component (color channel). */
 124
 125typedef struct {
 126  /* These values are fixed over the whole image. */
 127  /* For compression, they must be supplied by parameter setup; */
 128  /* for decompression, they are read from the SOF marker. */
 129  int component_id;		/* identifier for this component (0..255) */
 130  int component_index;		/* its index in SOF or cinfo->comp_info[] */
 131  int h_samp_factor;		/* horizontal sampling factor (1..4) */
 132  int v_samp_factor;		/* vertical sampling factor (1..4) */
 133  int quant_tbl_no;		/* quantization table selector (0..3) */
 134  /* These values may vary between scans. */
 135  /* For compression, they must be supplied by parameter setup; */
 136  /* for decompression, they are read from the SOS marker. */
 137  /* The decompressor output side may not use these variables. */
 138  int dc_tbl_no;		/* DC entropy table selector (0..3) */
 139  int ac_tbl_no;		/* AC entropy table selector (0..3) */
 140  
 141  /* Remaining fields should be treated as private by applications. */
 142  
 143  /* These values are computed during compression or decompression startup: */
 144  /* Component's size in DCT blocks.
 145   * Any dummy blocks added to complete an MCU are not counted; therefore
 146   * these values do not depend on whether a scan is interleaved or not.
 147   */
 148  JDIMENSION width_in_blocks;
 149  JDIMENSION height_in_blocks;
 150  /* Size of a DCT block in samples,
 151   * reflecting any scaling we choose to apply during the DCT step.
 152   * Values from 1 to 16 are supported.
 153   * Note that different components may receive different DCT scalings.
 154   */
 155  int DCT_h_scaled_size;
 156  int DCT_v_scaled_size;
 157  /* The downsampled dimensions are the component's actual, unpadded number
 158   * of samples at the main buffer (preprocessing/compression interface);
 159   * DCT scaling is included, so
 160   * downsampled_width = ceil(image_width * Hi/Hmax * DCT_h_scaled_size/DCTSIZE)
 161   * and similarly for height.
 162   */
 163  JDIMENSION downsampled_width;	 /* actual width in samples */
 164  JDIMENSION downsampled_height; /* actual height in samples */
 165  /* This flag is used only for decompression.  In cases where some of the
 166   * components will be ignored (eg grayscale output from YCbCr image),
 167   * we can skip most computations for the unused components.
 168   */
 169  boolean component_needed;	/* do we need the value of this component? */
 170
 171  /* These values are computed before starting a scan of the component. */
 172  /* The decompressor output side may not use these variables. */
 173  int MCU_width;		/* number of blocks per MCU, horizontally */
 174  int MCU_height;		/* number of blocks per MCU, vertically */
 175  int MCU_blocks;		/* MCU_width * MCU_height */
 176  int MCU_sample_width;	/* MCU width in samples: MCU_width * DCT_h_scaled_size */
 177  int last_col_width;		/* # of non-dummy blocks across in last MCU */
 178  int last_row_height;		/* # of non-dummy blocks down in last MCU */
 179
 180  /* Saved quantization table for component; NULL if none yet saved.
 181   * See jdinput.c comments about the need for this information.
 182   * This field is currently used only for decompression.
 183   */
 184  JQUANT_TBL * quant_table;
 185
 186  /* Private per-component storage for DCT or IDCT subsystem. */
 187  void * dct_table;
 188} jpeg_component_info;
 189
 190
 191/* The script for encoding a multiple-scan file is an array of these: */
 192
 193typedef struct {
 194  int comps_in_scan;		/* number of components encoded in this scan */
 195  int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
 196  int Ss, Se;			/* progressive JPEG spectral selection parms */
 197  int Ah, Al;			/* progressive JPEG successive approx. parms */
 198} jpeg_scan_info;
 199
 200/* The decompressor can save APPn and COM markers in a list of these: */
 201
 202typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
 203
 204struct jpeg_marker_struct {
 205  jpeg_saved_marker_ptr next;	/* next in list, or NULL */
 206  UINT8 marker;			/* marker code: JPEG_COM, or JPEG_APP0+n */
 207  unsigned int original_length;	/* # bytes of data in the file */
 208  unsigned int data_length;	/* # bytes of data saved at data[] */
 209  JOCTET FAR * data;		/* the data contained in the marker */
 210  /* the marker length word is not counted in data_length or original_length */
 211};
 212
 213/* Known color spaces. */
 214
 215typedef enum {
 216	JCS_UNKNOWN,		/* error/unspecified */
 217	JCS_GRAYSCALE,		/* monochrome */
 218	JCS_RGB,		/* red/green/blue */
 219	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV) */
 220	JCS_CMYK,		/* C/M/Y/K */
 221	JCS_YCCK		/* Y/Cb/Cr/K */
 222} J_COLOR_SPACE;
 223
 224/* DCT/IDCT algorithm options. */
 225
 226typedef enum {
 227	JDCT_ISLOW,		/* slow but accurate integer algorithm */
 228	JDCT_IFAST,		/* faster, less accurate integer method */
 229	JDCT_FLOAT		/* floating-point: accurate, fast on fast HW */
 230} J_DCT_METHOD;
 231
 232#ifndef JDCT_DEFAULT		/* may be overridden in jconfig.h */
 233#define JDCT_DEFAULT  JDCT_ISLOW
 234#endif
 235#ifndef JDCT_FASTEST		/* may be overridden in jconfig.h */
 236#define JDCT_FASTEST  JDCT_IFAST
 237#endif
 238
 239/* Dithering options for decompression. */
 240
 241typedef enum {
 242	JDITHER_NONE,		/* no dithering */
 243	JDITHER_ORDERED,	/* simple ordered dither */
 244	JDITHER_FS		/* Floyd-Steinberg error diffusion dither */
 245} J_DITHER_MODE;
 246
 247
 248/* Common fields between JPEG compression and decompression master structs. */
 249
 250#define jpeg_common_fields \
 251  struct jpeg_error_mgr * err;	/* Error handler module */\
 252  struct jpeg_memory_mgr * mem;	/* Memory manager module */\
 253  struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
 254  void * client_data;		/* Available for use by application */\
 255  boolean is_decompressor;	/* So common code can tell which is which */\
 256  int global_state		/* For checking call sequence validity */
 257
 258/* Routines that are to be used by both halves of the library are declared
 259 * to receive a pointer to this structure.  There are no actual instances of
 260 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
 261 */
 262struct jpeg_common_struct {
 263  jpeg_common_fields;		/* Fields common to both master struct types */
 264  /* Additional fields follow in an actual jpeg_compress_struct or
 265   * jpeg_decompress_struct.  All three structs must agree on these
 266   * initial fields!  (This would be a lot cleaner in C++.)
 267   */
 268};
 269
 270typedef struct jpeg_common_struct * j_common_ptr;
 271typedef struct jpeg_compress_struct * j_compress_ptr;
 272typedef struct jpeg_decompress_struct * j_decompress_ptr;
 273
 274
 275/* Master record for a compression instance */
 276
 277struct jpeg_compress_struct {
 278  jpeg_common_fields;		/* Fields shared with jpeg_decompress_struct */
 279
 280  /* Destination for compressed data */
 281  struct jpeg_destination_mgr * dest;
 282
 283  /* Description of source image --- these fields must be filled in by
 284   * outer application before starting compression.  in_color_space must
 285   * be correct before you can even call jpeg_set_defaults().
 286   */
 287
 288  JDIMENSION image_width;	/* input image width */
 289  JDIMENSION image_height;	/* input image height */
 290  int input_components;		/* # of color components in input image */
 291  J_COLOR_SPACE in_color_space;	/* colorspace of input image */
 292
 293  double input_gamma;		/* image gamma of input image */
 294
 295  /* Compression parameters --- these fields must be set before calling
 296   * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to
 297   * initialize everything to reasonable defaults, then changing anything
 298   * the application specifically wants to change.  That way you won't get
 299   * burnt when new parameters are added.  Also note that there are several
 300   * helper routines to simplify changing parameters.
 301   */
 302
 303  unsigned int scale_num, scale_denom; /* fraction by which to scale image */
 304
 305  JDIMENSION jpeg_width;	/* scaled JPEG image width */
 306  JDIMENSION jpeg_height;	/* scaled JPEG image height */
 307  /* Dimensions of actual JPEG image that will be written to file,
 308   * derived from input dimensions by scaling factors above.
 309   * These fields are computed by jpeg_start_compress().
 310   * You can also use jpeg_calc_jpeg_dimensions() to determine these values
 311   * in advance of calling jpeg_start_compress().
 312   */
 313
 314  int data_precision;		/* bits of precision in image data */
 315
 316  int num_components;		/* # of color components in JPEG image */
 317  J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
 318
 319  jpeg_component_info * comp_info;
 320  /* comp_info[i] describes component that appears i'th in SOF */
 321
 322  JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
 323  int q_scale_factor[NUM_QUANT_TBLS];
 324  /* ptrs to coefficient quantization tables, or NULL if not defined,
 325   * and corresponding scale factors (percentage, initialized 100).
 326   */
 327
 328  JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
 329  JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
 330  /* ptrs to Huffman coding tables, or NULL if not defined */
 331
 332  UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
 333  UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
 334  UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
 335
 336  int num_scans;		/* # of entries in scan_info array */
 337  const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
 338  /* The default value of scan_info is NULL, which causes a single-scan
 339   * sequential JPEG file to be emitted.  To create a multi-scan file,
 340   * set num_scans and scan_info to point to an array of scan definitions.
 341   */
 342
 343  boolean raw_data_in;		/* TRUE=caller supplies downsampled data */
 344  boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
 345  boolean optimize_coding;	/* TRUE=optimize entropy encoding parms */
 346  boolean CCIR601_sampling;	/* TRUE=first samples are cosited */
 347  boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
 348  int smoothing_factor;		/* 1..100, or 0 for no input smoothing */
 349  J_DCT_METHOD dct_method;	/* DCT algorithm selector */
 350
 351  /* The restart interval can be specified in absolute MCUs by setting
 352   * restart_interval, or in MCU rows by setting restart_in_rows
 353   * (in which case the correct restart_interval will be figured
 354   * for each scan).
 355   */
 356  unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
 357  int restart_in_rows;		/* if > 0, MCU rows per restart interval */
 358
 359  /* Parameters controlling emission of special markers. */
 360
 361  boolean write_JFIF_header;	/* should a JFIF marker be written? */
 362  UINT8 JFIF_major_version;	/* What to write for the JFIF version number */
 363  UINT8 JFIF_minor_version;
 364  /* These three values are not used by the JPEG code, merely copied */
 365  /* into the JFIF APP0 marker.  density_unit can be 0 for unknown, */
 366  /* 1 for dots/inch, or 2 for dots/cm.  Note that the pixel aspect */
 367  /* ratio is defined by X_density/Y_density even when density_unit=0. */
 368  UINT8 density_unit;		/* JFIF code for pixel size units */
 369  UINT16 X_density;		/* Horizontal pixel density */
 370  UINT16 Y_density;		/* Vertical pixel density */
 371  boolean write_Adobe_marker;	/* should an Adobe marker be written? */
 372  
 373  /* State variable: index of next scanline to be written to
 374   * jpeg_write_scanlines().  Application may use this to control its
 375   * processing loop, e.g., "while (next_scanline < image_height)".
 376   */
 377
 378  JDIMENSION next_scanline;	/* 0 .. image_height-1  */
 379
 380  /* Remaining fields are known throughout compressor, but generally
 381   * should not be touched by a surrounding application.
 382   */
 383
 384  /*
 385   * These fields are computed during compression startup
 386   */
 387  boolean progressive_mode;	/* TRUE if scan script uses progressive mode */
 388  int max_h_samp_factor;	/* largest h_samp_factor */
 389  int max_v_samp_factor;	/* largest v_samp_factor */
 390
 391  int min_DCT_h_scaled_size;	/* smallest DCT_h_scaled_size of any component */
 392  int min_DCT_v_scaled_size;	/* smallest DCT_v_scaled_size of any component */
 393
 394  JDIMENSION total_iMCU_rows;	/* # of iMCU rows to be input to coef ctlr */
 395  /* The coefficient controller receives data in units of MCU rows as defined
 396   * for fully interleaved scans (whether the JPEG file is interleaved or not).
 397   * There are v_samp_factor * DCTSIZE sample rows of each component in an
 398   * "iMCU" (interleaved MCU) row.
 399   */
 400  
 401  /*
 402   * These fields are valid during any one scan.
 403   * They describe the components and MCUs actually appearing in the scan.
 404   */
 405  int comps_in_scan;		/* # of JPEG components in this scan */
 406  jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
 407  /* *cur_comp_info[i] describes component that appears i'th in SOS */
 408  
 409  JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
 410  JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */
 411  
 412  int blocks_in_MCU;		/* # of DCT blocks per MCU */
 413  int MCU_membership[C_MAX_BLOCKS_IN_MCU];
 414  /* MCU_membership[i] is index in cur_comp_info of component owning */
 415  /* i'th block in an MCU */
 416
 417  int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */
 418
 419  int block_size;		/* the basic DCT block size: 1..16 */
 420  const int * natural_order;	/* natural-order position array */
 421  int lim_Se;			/* min( Se, DCTSIZE2-1 ) */
 422
 423  /*
 424   * Links to compression subobjects (methods and private variables of modules)
 425   */
 426  struct jpeg_comp_master * master;
 427  struct jpeg_c_main_controller * main;
 428  struct jpeg_c_prep_controller * prep;
 429  struct jpeg_c_coef_controller * coef;
 430  struct jpeg_marker_writer * marker;
 431  struct jpeg_color_converter * cconvert;
 432  struct jpeg_downsampler * downsample;
 433  struct jpeg_forward_dct * fdct;
 434  struct jpeg_entropy_encoder * entropy;
 435  jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
 436  int script_space_size;
 437};
 438
 439
 440/* Master record for a decompression instance */
 441
 442struct jpeg_decompress_struct {
 443  jpeg_common_fields;		/* Fields shared with jpeg_compress_struct */
 444
 445  /* Source of compressed data */
 446  struct jpeg_source_mgr * src;
 447
 448  /* Basic description of image --- filled in by jpeg_read_header(). */
 449  /* Application may inspect these values to decide how to process image. */
 450
 451  JDIMENSION image_width;	/* nominal image width (from SOF marker) */
 452  JDIMENSION image_height;	/* nominal image height */
 453  int num_components;		/* # of color components in JPEG image */
 454  J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
 455
 456  /* Decompression processing parameters --- these fields must be set before
 457   * calling jpeg_start_decompress().  Note that jpeg_read_header() initializes
 458   * them to default values.
 459   */
 460
 461  J_COLOR_SPACE out_color_space; /* colorspace for output */
 462
 463  unsigned int scale_num, scale_denom; /* fraction by which to scale image */
 464
 465  double output_gamma;		/* image gamma wanted in output */
 466
 467  boolean buffered_image;	/* TRUE=multiple output passes */
 468  boolean raw_data_out;		/* TRUE=downsampled data wanted */
 469
 470  J_DCT_METHOD dct_method;	/* IDCT algorithm selector */
 471  boolean do_fancy_upsampling;	/* TRUE=apply fancy upsampling */
 472  boolean do_block_smoothing;	/* TRUE=apply interblock smoothing */
 473
 474  boolean quantize_colors;	/* TRUE=colormapped output wanted */
 475  /* the following are ignored if not quantize_colors: */
 476  J_DITHER_MODE dither_mode;	/* type of color dithering to use */
 477  boolean two_pass_quantize;	/* TRUE=use two-pass color quantization */
 478  int desired_number_of_colors;	/* max # colors to use in created colormap */
 479  /* these are significant only in buffered-image mode: */
 480  boolean enable_1pass_quant;	/* enable future use of 1-pass quantizer */
 481  boolean enable_external_quant;/* enable future use of external colormap */
 482  boolean enable_2pass_quant;	/* enable future use of 2-pass quantizer */
 483
 484  /* Description of actual output image that will be returned to application.
 485   * These fields are computed by jpeg_start_decompress().
 486   * You can also use jpeg_calc_output_dimensions() to determine these values
 487   * in advance of calling jpeg_start_decompress().
 488   */
 489
 490  JDIMENSION output_width;	/* scaled image width */
 491  JDIMENSION output_height;	/* scaled image height */
 492  int out_color_components;	/* # of color components in out_color_space */
 493  int output_components;	/* # of color components returned */
 494  /* output_components is 1 (a colormap index) when quantizing colors;
 495   * otherwise it equals out_color_components.
 496   */
 497  int rec_outbuf_height;	/* min recommended height of scanline buffer */
 498  /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
 499   * high, space and time will be wasted due to unnecessary data copying.
 500   * Usually rec_outbuf_height will be 1 or 2, at most 4.
 501   */
 502
 503  /* When quantizing colors, the output colormap is described by these fields.
 504   * The application can supply a colormap by setting colormap non-NULL before
 505   * calling jpeg_start_decompress; otherwise a colormap is created during
 506   * jpeg_start_decompress or jpeg_start_output.
 507   * The map has out_color_components rows and actual_number_of_colors columns.
 508   */
 509  int actual_number_of_colors;	/* number of entries in use */
 510  JSAMPARRAY colormap;		/* The color map as a 2-D pixel array */
 511
 512  /* State variables: these variables indicate the progress of decompression.
 513   * The application may examine these but must not modify them.
 514   */
 515
 516  /* Row index of next scanline to be read from jpeg_read_scanlines().
 517   * Application may use this to control its processing loop, e.g.,
 518   * "while (output_scanline < output_height)".
 519   */
 520  JDIMENSION output_scanline;	/* 0 .. output_height-1  */
 521
 522  /* Current input scan number and number of iMCU rows completed in scan.
 523   * These indicate the progress of the decompressor input side.
 524   */
 525  int input_scan_number;	/* Number of SOS markers seen so far */
 526  JDIMENSION input_iMCU_row;	/* Number of iMCU rows completed */
 527
 528  /* The "output scan number" is the notional scan being displayed by the
 529   * output side.  The decompressor will not allow output scan/row number
 530   * to get ahead of input scan/row, but it can fall arbitrarily far behind.
 531   */
 532  int output_scan_number;	/* Nominal scan number being displayed */
 533  JDIMENSION output_iMCU_row;	/* Number of iMCU rows read */
 534
 535  /* Current progression status.  coef_bits[c][i] indicates the precision
 536   * with which component c's DCT coefficient i (in zigzag order) is known.
 537   * It is -1 when no data has yet been received, otherwise it is the point
 538   * transform (shift) value for the most recent scan of the coefficient
 539   * (thus, 0 at completion of the progression).
 540   * This pointer is NULL when reading a non-progressive file.
 541   */
 542  int (*coef_bits)[DCTSIZE2];	/* -1 or current Al value for each coef */
 543
 544  /* Internal JPEG parameters --- the application usually need not look at
 545   * these fields.  Note that the decompressor output side may not use
 546   * any parameters that can change between scans.
 547   */
 548
 549  /* Quantization and Huffman tables are carried forward across input
 550   * datastreams when processing abbreviated JPEG datastreams.
 551   */
 552
 553  JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
 554  /* ptrs to coefficient quantization tables, or NULL if not defined */
 555
 556  JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
 557  JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
 558  /* ptrs to Huffman coding tables, or NULL if not defined */
 559
 560  /* These parameters are never carried across datastreams, since they
 561   * are given in SOF/SOS markers or defined to be reset by SOI.
 562   */
 563
 564  int data_precision;		/* bits of precision in image data */
 565
 566  jpeg_component_info * comp_info;
 567  /* comp_info[i] describes component that appears i'th in SOF */
 568
 569  boolean is_baseline;		/* TRUE if Baseline SOF0 encountered */
 570  boolean progressive_mode;	/* TRUE if SOFn specifies progressive mode */
 571  boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
 572
 573  UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
 574  UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
 575  UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
 576
 577  unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
 578
 579  /* These fields record data obtained from optional markers recognized by
 580   * the JPEG library.
 581   */
 582  boolean saw_JFIF_marker;	/* TRUE iff a JFIF APP0 marker was found */
 583  /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
 584  UINT8 JFIF_major_version;	/* JFIF version number */
 585  UINT8 JFIF_minor_version;
 586  UINT8 density_unit;		/* JFIF code for pixel size units */
 587  UINT16 X_density;		/* Horizontal pixel density */
 588  UINT16 Y_density;		/* Vertical pixel density */
 589  boolean saw_Adobe_marker;	/* TRUE iff an Adobe APP14 marker was found */
 590  UINT8 Adobe_transform;	/* Color transform code from Adobe marker */
 591
 592  boolean CCIR601_sampling;	/* TRUE=first samples are cosited */
 593
 594  /* Aside from the specific data retained from APPn markers known to the
 595   * library, the uninterpreted contents of any or all APPn and COM markers
 596   * can be saved in a list for examination by the application.
 597   */
 598  jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
 599
 600  /* Remaining fields are known throughout decompressor, but generally
 601   * should not be touched by a surrounding application.
 602   */
 603
 604  /*
 605   * These fields are computed during decompression startup
 606   */
 607  int max_h_samp_factor;	/* largest h_samp_factor */
 608  int max_v_samp_factor;	/* largest v_samp_factor */
 609
 610  int min_DCT_h_scaled_size;	/* smallest DCT_h_scaled_size of any component */
 611  int min_DCT_v_scaled_size;	/* smallest DCT_v_scaled_size of any component */
 612
 613  JDIMENSION total_iMCU_rows;	/* # of iMCU rows in image */
 614  /* The coefficient controller's input and output progress is measured in
 615   * units of "iMCU" (interleaved MCU) rows.  These are the same as MCU rows
 616   * in fully interleaved JPEG scans, but are used whether the scan is
 617   * interleaved or not.  We define an iMCU row as v_samp_factor DCT block
 618   * rows of each component.  Therefore, the IDCT output contains
 619   * v_samp_factor*DCT_v_scaled_size sample rows of a component per iMCU row.
 620   */
 621
 622  JSAMPLE * sample_range_limit; /* table for fast range-limiting */
 623
 624  /*
 625   * These fields are valid during any one scan.
 626   * They describe the components and MCUs actually appearing in the scan.
 627   * Note that the decompressor output side must not use these fields.
 628   */
 629  int comps_in_scan;		/* # of JPEG components in this scan */
 630  jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
 631  /* *cur_comp_info[i] describes component that appears i'th in SOS */
 632
 633  JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
 634  JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */
 635
 636  int blocks_in_MCU;		/* # of DCT blocks per MCU */
 637  int MCU_membership[D_MAX_BLOCKS_IN_MCU];
 638  /* MCU_membership[i] is index in cur_comp_info of component owning */
 639  /* i'th block in an MCU */
 640
 641  int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */
 642
 643  /* These fields are derived from Se of first SOS marker.
 644   */
 645  int block_size;		/* the basic DCT block size: 1..16 */
 646  const int * natural_order; /* natural-order position array for entropy decode */
 647  int lim_Se;			/* min( Se, DCTSIZE2-1 ) for entropy decode */
 648
 649  /* This field is shared between entropy decoder and marker parser.
 650   * It is either zero or the code of a JPEG marker that has been
 651   * read from the data source, but has not yet been processed.
 652   */
 653  int unread_marker;
 654
 655  /*
 656   * Links to decompression subobjects (methods, private variables of modules)
 657   */
 658  struct jpeg_decomp_master * master;
 659  struct jpeg_d_main_controller * main;
 660  struct jpeg_d_coef_controller * coef;
 661  struct jpeg_d_post_controller * post;
 662  struct jpeg_input_controller * inputctl;
 663  struct jpeg_marker_reader * marker;
 664  struct jpeg_entropy_decoder * entropy;
 665  struct jpeg_inverse_dct * idct;
 666  struct jpeg_upsampler * upsample;
 667  struct jpeg_color_deconverter * cconvert;
 668  struct jpeg_color_quantizer * cquantize;
 669};
 670
 671
 672/* "Object" declarations for JPEG modules that may be supplied or called
 673 * directly by the surrounding application.
 674 * As with all objects in the JPEG library, these structs only define the
 675 * publicly visible methods and state variables of a module.  Additional
 676 * private fields may exist after the public ones.
 677 */
 678
 679
 680/* Error handler object */
 681
 682struct jpeg_error_mgr {
 683  /* Error exit handler: does not return to caller */
 684  JMETHOD(void, error_exit, (j_common_ptr cinfo));
 685  /* Conditionally emit a trace or warning message */
 686  JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
 687  /* Routine that actually outputs a trace or error message */
 688  JMETHOD(void, output_message, (j_common_ptr cinfo));
 689  /* Format a message string for the most recent JPEG error or message */
 690  JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
 691#define JMSG_LENGTH_MAX  200	/* recommended size of format_message buffer */
 692  /* Reset error state variables at start of a new image */
 693  JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
 694  
 695  /* The message ID code and any parameters are saved here.
 696   * A message can have one string parameter or up to 8 int parameters.
 697   */
 698  int msg_code;
 699#define JMSG_STR_PARM_MAX  80
 700  union {
 701    int i[8];
 702    char s[JMSG_STR_PARM_MAX];
 703  } msg_parm;
 704  
 705  /* Standard state variables for error facility */
 706  
 707  int trace_level;		/* max msg_level that will be displayed */
 708  
 709  /* For recoverable corrupt-data errors, we emit a warning message,
 710   * but keep going unless emit_message chooses to abort.  emit_message
 711   * should count warnings in num_warnings.  The surrounding application
 712   * can check for bad data by seeing if num_warnings is nonzero at the
 713   * end of processing.
 714   */
 715  long num_warnings;		/* number of corrupt-data warnings */
 716
 717  /* These fields point to the table(s) of error message strings.
 718   * An application can change the table pointer to switch to a different
 719   * message list (typically, to change the language in which errors are
 720   * reported).  Some applications may wish to add additional error codes
 721   * that will be handled by the JPEG library error mechanism; the second
 722   * table pointer is used for this purpose.
 723   *
 724   * First table includes all errors generated by JPEG library itself.
 725   * Error code 0 is reserved for a "no such error string" message.
 726   */
 727  const char * const * jpeg_message_table; /* Library errors */
 728  int last_jpeg_message;    /* Table contains strings 0..last_jpeg_message */
 729  /* Second table can be added by application (see cjpeg/djpeg for example).
 730   * It contains strings numbered first_addon_message..last_addon_message.
 731   */
 732  const char * const * addon_message_table; /* Non-library errors */
 733  int first_addon_message;	/* code for first string in addon table */
 734  int last_addon_message;	/* code for last string in addon table */
 735};
 736
 737
 738/* Progress monitor object */
 739
 740struct jpeg_progress_mgr {
 741  JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
 742
 743  long pass_counter;		/* work units completed in this pass */
 744  long pass_limit;		/* total number of work units in this pass */
 745  int completed_passes;		/* passes completed so far */
 746  int total_passes;		/* total number of passes expected */
 747};
 748
 749
 750/* Data destination object for compression */
 751
 752struct jpeg_destination_mgr {
 753  JOCTET * next_output_byte;	/* => next byte to write in buffer */
 754  size_t free_in_buffer;	/* # of byte spaces remaining in buffer */
 755
 756  JMETHOD(void, init_destination, (j_compress_ptr cinfo));
 757  JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
 758  JMETHOD(void, term_destination, (j_compress_ptr cinfo));
 759};
 760
 761
 762/* Data source object for decompression */
 763
 764struct jpeg_source_mgr {
 765  const JOCTET * next_input_byte; /* => next byte to read from buffer */
 766  size_t bytes_in_buffer;	/* # of bytes remaining in buffer */
 767
 768  JMETHOD(void, init_source, (j_decompress_ptr cinfo));
 769  JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
 770  JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
 771  JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
 772  JMETHOD(void, term_source, (j_decompress_ptr cinfo));
 773};
 774
 775
 776/* Memory manager object.
 777 * Allocates "small" objects (a few K total), "large" objects (tens of K),
 778 * and "really big" objects (virtual arrays with backing store if needed).
 779 * The memory manager does not allow individual objects to be freed; rather,
 780 * each created object is assigned to a pool, and whole pools can be freed
 781 * at once.  This is faster and more convenient than remembering exactly what
 782 * to free, especially where malloc()/free() are not too speedy.
 783 * NB: alloc routines never return NULL.  They exit to error_exit if not
 784 * successful.
 785 */
 786
 787#define JPOOL_PERMANENT	0	/* lasts until master record is destroyed */
 788#define JPOOL_IMAGE	1	/* lasts until done with image/datastream */
 789#define JPOOL_NUMPOOLS	2
 790
 791typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
 792typedef struct jvirt_barray_control * jvirt_barray_ptr;
 793
 794
 795struct jpeg_memory_mgr {
 796  /* Method pointers */
 797  JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
 798				size_t sizeofobject));
 799  JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
 800				     size_t sizeofobject));
 801  JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
 802				     JDIMENSION samplesperrow,
 803				     JDIMENSION numrows));
 804  JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
 805				      JDIMENSION blocksperrow,
 806				      JDIMENSION numrows));
 807  JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
 808						  int pool_id,
 809						  boolean pre_zero,
 810						  JDIMENSION samplesperrow,
 811						  JDIMENSION numrows,
 812						  JDIMENSION maxaccess));
 813  JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
 814						  int pool_id,
 815						  boolean pre_zero,
 816						  JDIMENSION blocksperrow,
 817						  JDIMENSION numrows,
 818						  JDIMENSION maxaccess));
 819  JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
 820  JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
 821					   jvirt_sarray_ptr ptr,
 822					   JDIMENSION start_row,
 823					   JDIMENSION num_rows,
 824					   boolean writable));
 825  JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
 826					    jvirt_barray_ptr ptr,
 827					    JDIMENSION start_row,
 828					    JDIMENSION num_rows,
 829					    boolean writable));
 830  JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
 831  JMETHOD(void, self_destruct, (j_common_ptr cinfo));
 832
 833  /* Limit on memory allocation for this JPEG object.  (Note that this is
 834   * merely advisory, not a guaranteed maximum; it only affects the space
 835   * used for virtual-array buffers.)  May be changed by outer application
 836   * after creating the JPEG object.
 837   */
 838  long max_memory_to_use;
 839
 840  /* Maximum allocation request accepted by alloc_large. */
 841  long max_alloc_chunk;
 842};
 843
 844
 845/* Routine signature for application-supplied marker processing methods.
 846 * Need not pass marker code since it is stored in cinfo->unread_marker.
 847 */
 848typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
 849
 850
 851/* Declarations for routines called by application.
 852 * The JPP macro hides prototype parameters from compilers that can't cope.
 853 * Note JPP requires double parentheses.
 854 */
 855
 856#ifdef HAVE_PROTOTYPES
 857#define JPP(arglist)	arglist
 858#else
 859#define JPP(arglist)	()
 860#endif
 861
 862
 863/* Short forms of external names for systems with brain-damaged linkers.
 864 * We shorten external names to be unique in the first six letters, which
 865 * is good enough for all known systems.
 866 * (If your compiler itself needs names to be unique in less than 15 
 867 * characters, you are out of luck.  Get a better compiler.)
 868 */
 869
 870#ifdef NEED_SHORT_EXTERNAL_NAMES
 871#define jpeg_std_error		jStdError
 872#define jpeg_CreateCompress	jCreaCompress
 873#define jpeg_CreateDecompress	jCreaDecompress
 874#define jpeg_destroy_compress	jDestCompress
 875#define jpeg_destroy_decompress	jDestDecompress
 876#define jpeg_stdio_dest		jStdDest
 877#define jpeg_stdio_src		jStdSrc
 878#define jpeg_mem_dest		jMemDest
 879#define jpeg_mem_src		jMemSrc
 880#define jpeg_set_defaults	jSetDefaults
 881#define jpeg_set_colorspace	jSetColorspace
 882#define jpeg_default_colorspace	jDefColorspace
 883#define jpeg_set_quality	jSetQuality
 884#define jpeg_set_linear_quality	jSetLQuality
 885#define jpeg_default_qtables	jDefQTables
 886#define jpeg_add_quant_table	jAddQuantTable
 887#define jpeg_quality_scaling	jQualityScaling
 888#define jpeg_simple_progression	jSimProgress
 889#define jpeg_suppress_tables	jSuppressTables
 890#define jpeg_alloc_quant_table	jAlcQTable
 891#define jpeg_alloc_huff_table	jAlcHTable
 892#define jpeg_start_compress	jStrtCompress
 893#define jpeg_write_scanlines	jWrtScanlines
 894#define jpeg_finish_compress	jFinCompress
 895#define jpeg_calc_jpeg_dimensions	jCjpegDimensions
 896#define jpeg_write_raw_data	jWrtRawData
 897#define jpeg_write_marker	jWrtMarker
 898#define jpeg_write_m_header	jWrtMHeader
 899#define jpeg_write_m_byte	jWrtMByte
 900#define jpeg_write_tables	jWrtTables
 901#define jpeg_read_header	jReadHeader
 902#define jpeg_start_decompress	jStrtDecompress
 903#define jpeg_read_scanlines	jReadScanlines
 904#define jpeg_finish_decompress	jFinDecompress
 905#define jpeg_read_raw_data	jReadRawData
 906#define jpeg_has_multiple_scans	jHasMultScn
 907#define jpeg_start_output	jStrtOutput
 908#define jpeg_finish_output	jFinOutput
 909#define jpeg_input_complete	jInComplete
 910#define jpeg_new_colormap	jNewCMap
 911#define jpeg_consume_input	jConsumeInput
 912#define jpeg_core_output_dimensions	jCoreDimensions
 913#define jpeg_calc_output_dimensions	jCalcDimensions
 914#define jpeg_save_markers	jSaveMarkers
 915#define jpeg_set_marker_processor	jSetMarker
 916#define jpeg_read_coefficients	jReadCoefs
 917#define jpeg_write_coefficients	jWrtCoefs
 918#define jpeg_copy_critical_parameters	jCopyCrit
 919#define jpeg_abort_compress	jAbrtCompress
 920#define jpeg_abort_decompress	jAbrtDecompress
 921#define jpeg_abort		jAbort
 922#define jpeg_destroy		jDestroy
 923#define jpeg_resync_to_restart	jResyncRestart
 924#endif /* NEED_SHORT_EXTERNAL_NAMES */
 925
 926
 927/* Default error-management setup */
 928EXTERN(struct jpeg_error_mgr *) jpeg_std_error
 929	JPP((struct jpeg_error_mgr * err));
 930
 931/* Initialization of JPEG compression objects.
 932 * jpeg_create_compress() and jpeg_create_decompress() are the exported
 933 * names that applications should call.  These expand to calls on
 934 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
 935 * passed for version mismatch checking.
 936 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
 937 */
 938#define jpeg_create_compress(cinfo) \
 939    jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
 940			(size_t) sizeof(struct jpeg_compress_struct))
 941#define jpeg_create_decompress(cinfo) \
 942    jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
 943			  (size_t) sizeof(struct jpeg_decompress_struct))
 944EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
 945				      int version, size_t structsize));
 946EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
 947					int version, size_t structsize));
 948/* Destruction of JPEG compression objects */
 949EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
 950EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
 951
 952/* Standard data source and destination managers: stdio streams. */
 953/* Caller is responsible for opening the file before and closing after. */
 954EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
 955EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
 956
 957/* Data source and destination managers: memory buffers. */
 958EXTERN(void) jpeg_mem_dest JPP((j_compress_ptr cinfo,
 959			       unsigned char ** outbuffer,
 960			       unsigned long * outsize));
 961EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo,
 962			      unsigned char * inbuffer,
 963			      unsigned long insize));
 964
 965/* Default parameter setup for compression */
 966EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
 967/* Compression parameter setup aids */
 968EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
 969				      J_COLOR_SPACE colorspace));
 970EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
 971EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
 972				   boolean force_baseline));
 973EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
 974					  int scale_factor,
 975					  boolean force_baseline));
 976EXTERN(void) jpeg_default_qtables JPP((j_compress_ptr cinfo,
 977				       boolean force_baseline));
 978EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
 979				       const unsigned int *basic_table,
 980				       int scale_factor,
 981				       boolean force_baseline));
 982EXTERN(int) jpeg_quality_scaling JPP((int quality));
 983EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
 984EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
 985				       boolean suppress));
 986EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
 987EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
 988
 989/* Main entry points for compression */
 990EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
 991				      boolean write_all_tables));
 992EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
 993					     JSAMPARRAY scanlines,
 994					     JDIMENSION num_lines));
 995EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
 996
 997/* Precalculate JPEG dimensions for current compression parameters. */
 998EXTERN(void) jpeg_calc_jpeg_dimensions JPP((j_compress_ptr cinfo));
 999
1000/* Replaces jpeg_write_scanlines when writing raw downsampled data. */
1001EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
1002					    JSAMPIMAGE data,
1003					    JDIMENSION num_lines));
1004
1005/* Write a special marker.  See libjpeg.txt concerning safe usage. */
1006EXTERN(void) jpeg_write_marker
1007	JPP((j_compress_ptr cinfo, int marker,
1008	     const JOCTET * dataptr, unsigned int datalen));
1009/* Same, but piecemeal. */
1010EXTERN(void) jpeg_write_m_header
1011	JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
1012EXTERN(void) jpeg_write_m_byte
1013	JPP((j_compress_ptr cinfo, int val));
1014
1015/* Alternate compression function: just write an abbreviated table file */
1016EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
1017
1018/* Decompression startup: read start of JPEG datastream to see what's there */
1019EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
1020				  boolean require_image));
1021/* Return value is one of: */
1022#define JPEG_SUSPENDED		0 /* Suspended due to lack of input data */
1023#define JPEG_HEADER_OK		1 /* Found valid image datastream */
1024#define JPEG_HEADER_TABLES_ONLY	2 /* Found valid table-specs-only datastream */
1025/* If you pass require_image = TRUE (normal case), you need not check for
1026 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
1027 * JPEG_SUSPENDED is only possible if you use a data source module that can
1028 * give a suspension return (the stdio source module doesn't).
1029 */
1030
1031/* Main entry points for decompression */
1032EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
1033EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
1034					    JSAMPARRAY scanlines,
1035					    JDIMENSION max_lines));
1036EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
1037
1038/* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1039EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
1040					   JSAMPIMAGE data,
1041					   JDIMENSION max_lines));
1042
1043/* Additional entry points for buffered-image mode. */
1044EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
1045EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
1046				       int scan_number));
1047EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
1048EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
1049EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1050EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
1051/* Return value is one of: */
1052/* #define JPEG_SUSPENDED	0    Suspended due to lack of input data */
1053#define JPEG_REACHED_SOS	1 /* Reached start of new scan */
1054#define JPEG_REACHED_EOI	2 /* Reached end of image */
1055#define JPEG_ROW_COMPLETED	3 /* Completed one iMCU row */
1056#define JPEG_SCAN_COMPLETED	4 /* Completed last iMCU row of a scan */
1057
1058/* Precalculate output dimensions for current decompression parameters. */
1059EXTERN(void) jpeg_core_output_dimensions JPP((j_decompress_ptr cinfo));
1060EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1061
1062/* Control saving of COM and APPn markers into marker_list. */
1063EXTERN(void) jpeg_save_markers
1064	JPP((j_decompress_ptr cinfo, int marker_code,
1065	     unsigned int length_limit));
1066
1067/* Install a special processing method for COM or APPn markers. */
1068EXTERN(void) jpeg_set_marker_processor
1069	JPP((j_decompress_ptr cinfo, int marker_code,
1070	     jpeg_marker_parser_method routine));
1071
1072/* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1073EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1074EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1075					  jvirt_barray_ptr * coef_arrays));
1076EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1077						j_compress_ptr dstinfo));
1078
1079/* If you choose to abort compression or decompression before completing
1080 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1081 * temporary files, etc.  You can just call jpeg_destroy_(de)compress
1082 * if you're done with the JPEG object, but if you want to clean it up and
1083 * reuse it, call this:
1084 */
1085EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
1086EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1087
1088/* Generic versions of jpeg_abort and jpeg_destroy that work on either
1089 * flavor of JPEG object.  These may be more convenient in some places.
1090 */
1091EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
1092EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
1093
1094/* Default restart-marker-resync procedure for use by data source modules */
1095EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1096					    int desired));
1097
1098
1099/* These marker codes are exported since applications and data source modules
1100 * are likely to want to use them.
1101 */
1102
1103#define JPEG_RST0	0xD0	/* RST0 marker code */
1104#define JPEG_EOI	0xD9	/* EOI marker code */
1105#define JPEG_APP0	0xE0	/* APP0 marker code */
1106#define JPEG_COM	0xFE	/* COM marker code */
1107
1108
1109/* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1110 * for structure definitions that are never filled in, keep it quiet by
1111 * supplying dummy definitions for the various substructures.
1112 */
1113
1114#ifdef INCOMPLETE_TYPES_BROKEN
1115#ifndef JPEG_INTERNALS		/* will be defined in jpegint.h */
1116struct jvirt_sarray_control { long dummy; };
1117struct jvirt_barray_control { long dummy; };
1118struct jpeg_comp_master { long dummy; };
1119struct jpeg_c_main_controller { long dummy; };
1120struct jpeg_c_prep_controller { long dummy; };
1121struct jpeg_c_coef_controller { long dummy; };
1122struct jpeg_marker_writer { long dummy; };
1123struct jpeg_color_converter { long dummy; };
1124struct jpeg_downsampler { long dummy; };
1125struct jpeg_forward_dct { long dummy; };
1126struct jpeg_entropy_encoder { long dummy; };
1127struct jpeg_decomp_master { long dummy; };
1128struct jpeg_d_main_controller { long dummy; };
1129struct jpeg_d_coef_controller { long dummy; };
1130struct jpeg_d_post_controller { long dummy; };
1131struct jpeg_input_controller { long dummy; };
1132struct jpeg_marker_reader { long dummy; };
1133struct jpeg_entropy_decoder { long dummy; };
1134struct jpeg_inverse_dct { long dummy; };
1135struct jpeg_upsampler { long dummy; };
1136struct jpeg_color_deconverter { long dummy; };
1137struct jpeg_color_quantizer { long dummy; };
1138#endif /* JPEG_INTERNALS */
1139#endif /* INCOMPLETE_TYPES_BROKEN */
1140
1141
1142/*
1143 * The JPEG library modules define JPEG_INTERNALS before including this file.
1144 * The internal structure declarations are read only when that is true.
1145 * Applications using the library should not include jpegint.h, but may wish
1146 * to include jerror.h.
1147 */
1148
1149#ifdef JPEG_INTERNALS
1150#include "jpegint.h"		/* fetch private declarations */
1151#include "jerror.h"		/* fetch error codes too */
1152#endif
1153
1154#ifdef __cplusplus
1155#ifndef DONT_USE_EXTERN_C
1156}
1157#endif
1158#endif
1159
1160#endif /* JPEGLIB_H */