1 /* 2 * jpeglib.h 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * Modified 2002-2012 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 32 extern "C" { 33 #endif 34 #endif 35 36 /* Version IDs for the JPEG library. 37 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 90". 38 */ 39 40 #define JPEG_LIB_VERSION 90 /* Compatibility version 9.0 */ 41 #define JPEG_LIB_VERSION_MAJOR 9 42 #define JPEG_LIB_VERSION_MINOR 0 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 75 typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */ 76 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */ 77 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */ 78 79 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */ 80 typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */ 81 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */ 82 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */ 83 84 typedef 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 92 typedef 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. */ 108 109 typedef 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). */ 124 125 typedef 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: */ 192 193 typedef 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: */ 201 202 typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr; 203 204 struct 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. */ 214 215 typedef 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 /* Supported color transforms. */ 225 226 typedef enum { 227 JCT_NONE = 0, 228 JCT_SUBTRACT_GREEN = 1 229 } J_COLOR_TRANSFORM; 230 231 /* DCT/IDCT algorithm options. */ 232 233 typedef enum { 234 JDCT_ISLOW, /* slow but accurate integer algorithm */ 235 JDCT_IFAST, /* faster, less accurate integer method */ 236 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */ 237 } J_DCT_METHOD; 238 239 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */ 240 #define JDCT_DEFAULT JDCT_ISLOW 241 #endif 242 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */ 243 #define JDCT_FASTEST JDCT_IFAST 244 #endif 245 246 /* Dithering options for decompression. */ 247 248 typedef enum { 249 JDITHER_NONE, /* no dithering */ 250 JDITHER_ORDERED, /* simple ordered dither */ 251 JDITHER_FS /* Floyd-Steinberg error diffusion dither */ 252 } J_DITHER_MODE; 253 254 255 /* Common fields between JPEG compression and decompression master structs. */ 256 257 #define jpeg_common_fields \ 258 struct jpeg_error_mgr * err; /* Error handler module */\ 259 struct jpeg_memory_mgr * mem; /* Memory manager module */\ 260 struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\ 261 void * client_data; /* Available for use by application */\ 262 boolean is_decompressor; /* So common code can tell which is which */\ 263 int global_state /* For checking call sequence validity */ 264 265 /* Routines that are to be used by both halves of the library are declared 266 * to receive a pointer to this structure. There are no actual instances of 267 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct. 268 */ 269 struct jpeg_common_struct { 270 jpeg_common_fields; /* Fields common to both master struct types */ 271 /* Additional fields follow in an actual jpeg_compress_struct or 272 * jpeg_decompress_struct. All three structs must agree on these 273 * initial fields! (This would be a lot cleaner in C++.) 274 */ 275 }; 276 277 typedef struct jpeg_common_struct * j_common_ptr; 278 typedef struct jpeg_compress_struct * j_compress_ptr; 279 typedef struct jpeg_decompress_struct * j_decompress_ptr; 280 281 282 /* Master record for a compression instance */ 283 284 struct jpeg_compress_struct { 285 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */ 286 287 /* Destination for compressed data */ 288 struct jpeg_destination_mgr * dest; 289 290 /* Description of source image --- these fields must be filled in by 291 * outer application before starting compression. in_color_space must 292 * be correct before you can even call jpeg_set_defaults(). 293 */ 294 295 JDIMENSION image_width; /* input image width */ 296 JDIMENSION image_height; /* input image height */ 297 int input_components; /* # of color components in input image */ 298 J_COLOR_SPACE in_color_space; /* colorspace of input image */ 299 300 double input_gamma; /* image gamma of input image */ 301 302 /* Compression parameters --- these fields must be set before calling 303 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to 304 * initialize everything to reasonable defaults, then changing anything 305 * the application specifically wants to change. That way you won't get 306 * burnt when new parameters are added. Also note that there are several 307 * helper routines to simplify changing parameters. 308 */ 309 310 unsigned int scale_num, scale_denom; /* fraction by which to scale image */ 311 312 JDIMENSION jpeg_width; /* scaled JPEG image width */ 313 JDIMENSION jpeg_height; /* scaled JPEG image height */ 314 /* Dimensions of actual JPEG image that will be written to file, 315 * derived from input dimensions by scaling factors above. 316 * These fields are computed by jpeg_start_compress(). 317 * You can also use jpeg_calc_jpeg_dimensions() to determine these values 318 * in advance of calling jpeg_start_compress(). 319 */ 320 321 int data_precision; /* bits of precision in image data */ 322 323 int num_components; /* # of color components in JPEG image */ 324 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */ 325 326 jpeg_component_info * comp_info; 327 /* comp_info[i] describes component that appears i'th in SOF */ 328 329 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS]; 330 int q_scale_factor[NUM_QUANT_TBLS]; 331 /* ptrs to coefficient quantization tables, or NULL if not defined, 332 * and corresponding scale factors (percentage, initialized 100). 333 */ 334 335 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS]; 336 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS]; 337 /* ptrs to Huffman coding tables, or NULL if not defined */ 338 339 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */ 340 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */ 341 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */ 342 343 int num_scans; /* # of entries in scan_info array */ 344 const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */ 345 /* The default value of scan_info is NULL, which causes a single-scan 346 * sequential JPEG file to be emitted. To create a multi-scan file, 347 * set num_scans and scan_info to point to an array of scan definitions. 348 */ 349 350 boolean raw_data_in; /* TRUE=caller supplies downsampled data */ 351 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */ 352 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */ 353 boolean CCIR601_sampling; /* TRUE=first samples are cosited */ 354 boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */ 355 int smoothing_factor; /* 1..100, or 0 for no input smoothing */ 356 J_DCT_METHOD dct_method; /* DCT algorithm selector */ 357 358 /* The restart interval can be specified in absolute MCUs by setting 359 * restart_interval, or in MCU rows by setting restart_in_rows 360 * (in which case the correct restart_interval will be figured 361 * for each scan). 362 */ 363 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */ 364 int restart_in_rows; /* if > 0, MCU rows per restart interval */ 365 366 /* Parameters controlling emission of special markers. */ 367 368 boolean write_JFIF_header; /* should a JFIF marker be written? */ 369 UINT8 JFIF_major_version; /* What to write for the JFIF version number */ 370 UINT8 JFIF_minor_version; 371 /* These three values are not used by the JPEG code, merely copied */ 372 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */ 373 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */ 374 /* ratio is defined by X_density/Y_density even when density_unit=0. */ 375 UINT8 density_unit; /* JFIF code for pixel size units */ 376 UINT16 X_density; /* Horizontal pixel density */ 377 UINT16 Y_density; /* Vertical pixel density */ 378 boolean write_Adobe_marker; /* should an Adobe marker be written? */ 379 380 J_COLOR_TRANSFORM color_transform; 381 /* Color transform identifier, writes LSE marker if nonzero */ 382 383 /* State variable: index of next scanline to be written to 384 * jpeg_write_scanlines(). Application may use this to control its 385 * processing loop, e.g., "while (next_scanline < image_height)". 386 */ 387 388 JDIMENSION next_scanline; /* 0 .. image_height-1 */ 389 390 /* Remaining fields are known throughout compressor, but generally 391 * should not be touched by a surrounding application. 392 */ 393 394 /* 395 * These fields are computed during compression startup 396 */ 397 boolean progressive_mode; /* TRUE if scan script uses progressive mode */ 398 int max_h_samp_factor; /* largest h_samp_factor */ 399 int max_v_samp_factor; /* largest v_samp_factor */ 400 401 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */ 402 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */ 403 404 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */ 405 /* The coefficient controller receives data in units of MCU rows as defined 406 * for fully interleaved scans (whether the JPEG file is interleaved or not). 407 * There are v_samp_factor * DCTSIZE sample rows of each component in an 408 * "iMCU" (interleaved MCU) row. 409 */ 410 411 /* 412 * These fields are valid during any one scan. 413 * They describe the components and MCUs actually appearing in the scan. 414 */ 415 int comps_in_scan; /* # of JPEG components in this scan */ 416 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN]; 417 /* *cur_comp_info[i] describes component that appears i'th in SOS */ 418 419 JDIMENSION MCUs_per_row; /* # of MCUs across the image */ 420 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */ 421 422 int blocks_in_MCU; /* # of DCT blocks per MCU */ 423 int MCU_membership[C_MAX_BLOCKS_IN_MCU]; 424 /* MCU_membership[i] is index in cur_comp_info of component owning */ 425 /* i'th block in an MCU */ 426 427 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */ 428 429 int block_size; /* the basic DCT block size: 1..16 */ 430 const int * natural_order; /* natural-order position array */ 431 int lim_Se; /* min( Se, DCTSIZE2-1 ) */ 432 433 /* 434 * Links to compression subobjects (methods and private variables of modules) 435 */ 436 struct jpeg_comp_master * master; 437 struct jpeg_c_main_controller * main; 438 struct jpeg_c_prep_controller * prep; 439 struct jpeg_c_coef_controller * coef; 440 struct jpeg_marker_writer * marker; 441 struct jpeg_color_converter * cconvert; 442 struct jpeg_downsampler * downsample; 443 struct jpeg_forward_dct * fdct; 444 struct jpeg_entropy_encoder * entropy; 445 jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */ 446 int script_space_size; 447 }; 448 449 450 /* Master record for a decompression instance */ 451 452 struct jpeg_decompress_struct { 453 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */ 454 455 /* Source of compressed data */ 456 struct jpeg_source_mgr * src; 457 458 /* Basic description of image --- filled in by jpeg_read_header(). */ 459 /* Application may inspect these values to decide how to process image. */ 460 461 JDIMENSION image_width; /* nominal image width (from SOF marker) */ 462 JDIMENSION image_height; /* nominal image height */ 463 int num_components; /* # of color components in JPEG image */ 464 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */ 465 466 /* Decompression processing parameters --- these fields must be set before 467 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes 468 * them to default values. 469 */ 470 471 J_COLOR_SPACE out_color_space; /* colorspace for output */ 472 473 unsigned int scale_num, scale_denom; /* fraction by which to scale image */ 474 475 double output_gamma; /* image gamma wanted in output */ 476 477 boolean buffered_image; /* TRUE=multiple output passes */ 478 boolean raw_data_out; /* TRUE=downsampled data wanted */ 479 480 J_DCT_METHOD dct_method; /* IDCT algorithm selector */ 481 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */ 482 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */ 483 484 boolean quantize_colors; /* TRUE=colormapped output wanted */ 485 /* the following are ignored if not quantize_colors: */ 486 J_DITHER_MODE dither_mode; /* type of color dithering to use */ 487 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */ 488 int desired_number_of_colors; /* max # colors to use in created colormap */ 489 /* these are significant only in buffered-image mode: */ 490 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */ 491 boolean enable_external_quant;/* enable future use of external colormap */ 492 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */ 493 494 /* Description of actual output image that will be returned to application. 495 * These fields are computed by jpeg_start_decompress(). 496 * You can also use jpeg_calc_output_dimensions() to determine these values 497 * in advance of calling jpeg_start_decompress(). 498 */ 499 500 JDIMENSION output_width; /* scaled image width */ 501 JDIMENSION output_height; /* scaled image height */ 502 int out_color_components; /* # of color components in out_color_space */ 503 int output_components; /* # of color components returned */ 504 /* output_components is 1 (a colormap index) when quantizing colors; 505 * otherwise it equals out_color_components. 506 */ 507 int rec_outbuf_height; /* min recommended height of scanline buffer */ 508 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows 509 * high, space and time will be wasted due to unnecessary data copying. 510 * Usually rec_outbuf_height will be 1 or 2, at most 4. 511 */ 512 513 /* When quantizing colors, the output colormap is described by these fields. 514 * The application can supply a colormap by setting colormap non-NULL before 515 * calling jpeg_start_decompress; otherwise a colormap is created during 516 * jpeg_start_decompress or jpeg_start_output. 517 * The map has out_color_components rows and actual_number_of_colors columns. 518 */ 519 int actual_number_of_colors; /* number of entries in use */ 520 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */ 521 522 /* State variables: these variables indicate the progress of decompression. 523 * The application may examine these but must not modify them. 524 */ 525 526 /* Row index of next scanline to be read from jpeg_read_scanlines(). 527 * Application may use this to control its processing loop, e.g., 528 * "while (output_scanline < output_height)". 529 */ 530 JDIMENSION output_scanline; /* 0 .. output_height-1 */ 531 532 /* Current input scan number and number of iMCU rows completed in scan. 533 * These indicate the progress of the decompressor input side. 534 */ 535 int input_scan_number; /* Number of SOS markers seen so far */ 536 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */ 537 538 /* The "output scan number" is the notional scan being displayed by the 539 * output side. The decompressor will not allow output scan/row number 540 * to get ahead of input scan/row, but it can fall arbitrarily far behind. 541 */ 542 int output_scan_number; /* Nominal scan number being displayed */ 543 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */ 544 545 /* Current progression status. coef_bits[c][i] indicates the precision 546 * with which component c's DCT coefficient i (in zigzag order) is known. 547 * It is -1 when no data has yet been received, otherwise it is the point 548 * transform (shift) value for the most recent scan of the coefficient 549 * (thus, 0 at completion of the progression). 550 * This pointer is NULL when reading a non-progressive file. 551 */ 552 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */ 553 554 /* Internal JPEG parameters --- the application usually need not look at 555 * these fields. Note that the decompressor output side may not use 556 * any parameters that can change between scans. 557 */ 558 559 /* Quantization and Huffman tables are carried forward across input 560 * datastreams when processing abbreviated JPEG datastreams. 561 */ 562 563 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS]; 564 /* ptrs to coefficient quantization tables, or NULL if not defined */ 565 566 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS]; 567 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS]; 568 /* ptrs to Huffman coding tables, or NULL if not defined */ 569 570 /* These parameters are never carried across datastreams, since they 571 * are given in SOF/SOS markers or defined to be reset by SOI. 572 */ 573 574 int data_precision; /* bits of precision in image data */ 575 576 jpeg_component_info * comp_info; 577 /* comp_info[i] describes component that appears i'th in SOF */ 578 579 boolean is_baseline; /* TRUE if Baseline SOF0 encountered */ 580 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */ 581 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */ 582 583 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */ 584 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */ 585 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */ 586 587 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */ 588 589 /* These fields record data obtained from optional markers recognized by 590 * the JPEG library. 591 */ 592 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */ 593 /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */ 594 UINT8 JFIF_major_version; /* JFIF version number */ 595 UINT8 JFIF_minor_version; 596 UINT8 density_unit; /* JFIF code for pixel size units */ 597 UINT16 X_density; /* Horizontal pixel density */ 598 UINT16 Y_density; /* Vertical pixel density */ 599 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */ 600 UINT8 Adobe_transform; /* Color transform code from Adobe marker */ 601 602 J_COLOR_TRANSFORM color_transform; 603 /* Color transform identifier derived from LSE marker, otherwise zero */ 604 605 boolean CCIR601_sampling; /* TRUE=first samples are cosited */ 606 607 /* Aside from the specific data retained from APPn markers known to the 608 * library, the uninterpreted contents of any or all APPn and COM markers 609 * can be saved in a list for examination by the application. 610 */ 611 jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */ 612 613 /* Remaining fields are known throughout decompressor, but generally 614 * should not be touched by a surrounding application. 615 */ 616 617 /* 618 * These fields are computed during decompression startup 619 */ 620 int max_h_samp_factor; /* largest h_samp_factor */ 621 int max_v_samp_factor; /* largest v_samp_factor */ 622 623 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */ 624 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */ 625 626 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */ 627 /* The coefficient controller's input and output progress is measured in 628 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows 629 * in fully interleaved JPEG scans, but are used whether the scan is 630 * interleaved or not. We define an iMCU row as v_samp_factor DCT block 631 * rows of each component. Therefore, the IDCT output contains 632 * v_samp_factor*DCT_v_scaled_size sample rows of a component per iMCU row. 633 */ 634 635 JSAMPLE * sample_range_limit; /* table for fast range-limiting */ 636 637 /* 638 * These fields are valid during any one scan. 639 * They describe the components and MCUs actually appearing in the scan. 640 * Note that the decompressor output side must not use these fields. 641 */ 642 int comps_in_scan; /* # of JPEG components in this scan */ 643 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN]; 644 /* *cur_comp_info[i] describes component that appears i'th in SOS */ 645 646 JDIMENSION MCUs_per_row; /* # of MCUs across the image */ 647 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */ 648 649 int blocks_in_MCU; /* # of DCT blocks per MCU */ 650 int MCU_membership[D_MAX_BLOCKS_IN_MCU]; 651 /* MCU_membership[i] is index in cur_comp_info of component owning */ 652 /* i'th block in an MCU */ 653 654 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */ 655 656 /* These fields are derived from Se of first SOS marker. 657 */ 658 int block_size; /* the basic DCT block size: 1..16 */ 659 const int * natural_order; /* natural-order position array for entropy decode */ 660 int lim_Se; /* min( Se, DCTSIZE2-1 ) for entropy decode */ 661 662 /* This field is shared between entropy decoder and marker parser. 663 * It is either zero or the code of a JPEG marker that has been 664 * read from the data source, but has not yet been processed. 665 */ 666 int unread_marker; 667 668 /* 669 * Links to decompression subobjects (methods, private variables of modules) 670 */ 671 struct jpeg_decomp_master * master; 672 struct jpeg_d_main_controller * main; 673 struct jpeg_d_coef_controller * coef; 674 struct jpeg_d_post_controller * post; 675 struct jpeg_input_controller * inputctl; 676 struct jpeg_marker_reader * marker; 677 struct jpeg_entropy_decoder * entropy; 678 struct jpeg_inverse_dct * idct; 679 struct jpeg_upsampler * upsample; 680 struct jpeg_color_deconverter * cconvert; 681 struct jpeg_color_quantizer * cquantize; 682 }; 683 684 685 /* "Object" declarations for JPEG modules that may be supplied or called 686 * directly by the surrounding application. 687 * As with all objects in the JPEG library, these structs only define the 688 * publicly visible methods and state variables of a module. Additional 689 * private fields may exist after the public ones. 690 */ 691 692 693 /* Error handler object */ 694 695 struct jpeg_error_mgr { 696 /* Error exit handler: does not return to caller */ 697 JMETHOD(noreturn_t, error_exit, (j_common_ptr cinfo)); 698 /* Conditionally emit a trace or warning message */ 699 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level)); 700 /* Routine that actually outputs a trace or error message */ 701 JMETHOD(void, output_message, (j_common_ptr cinfo)); 702 /* Format a message string for the most recent JPEG error or message */ 703 JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer)); 704 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */ 705 /* Reset error state variables at start of a new image */ 706 JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo)); 707 708 /* The message ID code and any parameters are saved here. 709 * A message can have one string parameter or up to 8 int parameters. 710 */ 711 int msg_code; 712 #define JMSG_STR_PARM_MAX 80 713 union { 714 int i[8]; 715 char s[JMSG_STR_PARM_MAX]; 716 } msg_parm; 717 718 /* Standard state variables for error facility */ 719 720 int trace_level; /* max msg_level that will be displayed */ 721 722 /* For recoverable corrupt-data errors, we emit a warning message, 723 * but keep going unless emit_message chooses to abort. emit_message 724 * should count warnings in num_warnings. The surrounding application 725 * can check for bad data by seeing if num_warnings is nonzero at the 726 * end of processing. 727 */ 728 long num_warnings; /* number of corrupt-data warnings */ 729 730 /* These fields point to the table(s) of error message strings. 731 * An application can change the table pointer to switch to a different 732 * message list (typically, to change the language in which errors are 733 * reported). Some applications may wish to add additional error codes 734 * that will be handled by the JPEG library error mechanism; the second 735 * table pointer is used for this purpose. 736 * 737 * First table includes all errors generated by JPEG library itself. 738 * Error code 0 is reserved for a "no such error string" message. 739 */ 740 const char * const * jpeg_message_table; /* Library errors */ 741 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */ 742 /* Second table can be added by application (see cjpeg/djpeg for example). 743 * It contains strings numbered first_addon_message..last_addon_message. 744 */ 745 const char * const * addon_message_table; /* Non-library errors */ 746 int first_addon_message; /* code for first string in addon table */ 747 int last_addon_message; /* code for last string in addon table */ 748 }; 749 750 751 /* Progress monitor object */ 752 753 struct jpeg_progress_mgr { 754 JMETHOD(void, progress_monitor, (j_common_ptr cinfo)); 755 756 long pass_counter; /* work units completed in this pass */ 757 long pass_limit; /* total number of work units in this pass */ 758 int completed_passes; /* passes completed so far */ 759 int total_passes; /* total number of passes expected */ 760 }; 761 762 763 /* Data destination object for compression */ 764 765 struct jpeg_destination_mgr { 766 JOCTET * next_output_byte; /* => next byte to write in buffer */ 767 size_t free_in_buffer; /* # of byte spaces remaining in buffer */ 768 769 JMETHOD(void, init_destination, (j_compress_ptr cinfo)); 770 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo)); 771 JMETHOD(void, term_destination, (j_compress_ptr cinfo)); 772 }; 773 774 775 /* Data source object for decompression */ 776 777 struct jpeg_source_mgr { 778 const JOCTET * next_input_byte; /* => next byte to read from buffer */ 779 size_t bytes_in_buffer; /* # of bytes remaining in buffer */ 780 781 JMETHOD(void, init_source, (j_decompress_ptr cinfo)); 782 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo)); 783 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes)); 784 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired)); 785 JMETHOD(void, term_source, (j_decompress_ptr cinfo)); 786 }; 787 788 789 /* Memory manager object. 790 * Allocates "small" objects (a few K total), "large" objects (tens of K), 791 * and "really big" objects (virtual arrays with backing store if needed). 792 * The memory manager does not allow individual objects to be freed; rather, 793 * each created object is assigned to a pool, and whole pools can be freed 794 * at once. This is faster and more convenient than remembering exactly what 795 * to free, especially where malloc()/free() are not too speedy. 796 * NB: alloc routines never return NULL. They exit to error_exit if not 797 * successful. 798 */ 799 800 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */ 801 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */ 802 #define JPOOL_NUMPOOLS 2 803 804 typedef struct jvirt_sarray_control * jvirt_sarray_ptr; 805 typedef struct jvirt_barray_control * jvirt_barray_ptr; 806 807 808 struct jpeg_memory_mgr { 809 /* Method pointers */ 810 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id, 811 size_t sizeofobject)); 812 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id, 813 size_t sizeofobject)); 814 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id, 815 JDIMENSION samplesperrow, 816 JDIMENSION numrows)); 817 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id, 818 JDIMENSION blocksperrow, 819 JDIMENSION numrows)); 820 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo, 821 int pool_id, 822 boolean pre_zero, 823 JDIMENSION samplesperrow, 824 JDIMENSION numrows, 825 JDIMENSION maxaccess)); 826 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo, 827 int pool_id, 828 boolean pre_zero, 829 JDIMENSION blocksperrow, 830 JDIMENSION numrows, 831 JDIMENSION maxaccess)); 832 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo)); 833 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo, 834 jvirt_sarray_ptr ptr, 835 JDIMENSION start_row, 836 JDIMENSION num_rows, 837 boolean writable)); 838 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo, 839 jvirt_barray_ptr ptr, 840 JDIMENSION start_row, 841 JDIMENSION num_rows, 842 boolean writable)); 843 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id)); 844 JMETHOD(void, self_destruct, (j_common_ptr cinfo)); 845 846 /* Limit on memory allocation for this JPEG object. (Note that this is 847 * merely advisory, not a guaranteed maximum; it only affects the space 848 * used for virtual-array buffers.) May be changed by outer application 849 * after creating the JPEG object. 850 */ 851 long max_memory_to_use; 852 853 /* Maximum allocation request accepted by alloc_large. */ 854 long max_alloc_chunk; 855 }; 856 857 858 /* Routine signature for application-supplied marker processing methods. 859 * Need not pass marker code since it is stored in cinfo->unread_marker. 860 */ 861 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo)); 862 863 864 /* Declarations for routines called by application. 865 * The JPP macro hides prototype parameters from compilers that can't cope. 866 * Note JPP requires double parentheses. 867 */ 868 869 #ifdef HAVE_PROTOTYPES 870 #define JPP(arglist) arglist 871 #else 872 #define JPP(arglist) () 873 #endif 874 875 876 /* Short forms of external names for systems with brain-damaged linkers. 877 * We shorten external names to be unique in the first six letters, which 878 * is good enough for all known systems. 879 * (If your compiler itself needs names to be unique in less than 15 880 * characters, you are out of luck. Get a better compiler.) 881 */ 882 883 #ifdef NEED_SHORT_EXTERNAL_NAMES 884 #define jpeg_std_error jStdError 885 #define jpeg_CreateCompress jCreaCompress 886 #define jpeg_CreateDecompress jCreaDecompress 887 #define jpeg_destroy_compress jDestCompress 888 #define jpeg_destroy_decompress jDestDecompress 889 #define jpeg_stdio_dest jStdDest 890 #define jpeg_stdio_src jStdSrc 891 #define jpeg_mem_dest jMemDest 892 #define jpeg_mem_src jMemSrc 893 #define jpeg_set_defaults jSetDefaults 894 #define jpeg_set_colorspace jSetColorspace 895 #define jpeg_default_colorspace jDefColorspace 896 #define jpeg_set_quality jSetQuality 897 #define jpeg_set_linear_quality jSetLQuality 898 #define jpeg_default_qtables jDefQTables 899 #define jpeg_add_quant_table jAddQuantTable 900 #define jpeg_quality_scaling jQualityScaling 901 #define jpeg_simple_progression jSimProgress 902 #define jpeg_suppress_tables jSuppressTables 903 #define jpeg_alloc_quant_table jAlcQTable 904 #define jpeg_alloc_huff_table jAlcHTable 905 #define jpeg_start_compress jStrtCompress 906 #define jpeg_write_scanlines jWrtScanlines 907 #define jpeg_finish_compress jFinCompress 908 #define jpeg_calc_jpeg_dimensions jCjpegDimensions 909 #define jpeg_write_raw_data jWrtRawData 910 #define jpeg_write_marker jWrtMarker 911 #define jpeg_write_m_header jWrtMHeader 912 #define jpeg_write_m_byte jWrtMByte 913 #define jpeg_write_tables jWrtTables 914 #define jpeg_read_header jReadHeader 915 #define jpeg_start_decompress jStrtDecompress 916 #define jpeg_read_scanlines jReadScanlines 917 #define jpeg_finish_decompress jFinDecompress 918 #define jpeg_read_raw_data jReadRawData 919 #define jpeg_has_multiple_scans jHasMultScn 920 #define jpeg_start_output jStrtOutput 921 #define jpeg_finish_output jFinOutput 922 #define jpeg_input_complete jInComplete 923 #define jpeg_new_colormap jNewCMap 924 #define jpeg_consume_input jConsumeInput 925 #define jpeg_core_output_dimensions jCoreDimensions 926 #define jpeg_calc_output_dimensions jCalcDimensions 927 #define jpeg_save_markers jSaveMarkers 928 #define jpeg_set_marker_processor jSetMarker 929 #define jpeg_read_coefficients jReadCoefs 930 #define jpeg_write_coefficients jWrtCoefs 931 #define jpeg_copy_critical_parameters jCopyCrit 932 #define jpeg_abort_compress jAbrtCompress 933 #define jpeg_abort_decompress jAbrtDecompress 934 #define jpeg_abort jAbort 935 #define jpeg_destroy jDestroy 936 #define jpeg_resync_to_restart jResyncRestart 937 #endif /* NEED_SHORT_EXTERNAL_NAMES */ 938 939 940 /* Default error-management setup */ 941 EXTERN(struct jpeg_error_mgr *) jpeg_std_error 942 JPP((struct jpeg_error_mgr * err)); 943 944 /* Initialization of JPEG compression objects. 945 * jpeg_create_compress() and jpeg_create_decompress() are the exported 946 * names that applications should call. These expand to calls on 947 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information 948 * passed for version mismatch checking. 949 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx. 950 */ 951 #define jpeg_create_compress(cinfo) \ 952 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \ 953 (size_t) sizeof(struct jpeg_compress_struct)) 954 #define jpeg_create_decompress(cinfo) \ 955 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \ 956 (size_t) sizeof(struct jpeg_decompress_struct)) 957 EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo, 958 int version, size_t structsize)); 959 EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo, 960 int version, size_t structsize)); 961 /* Destruction of JPEG compression objects */ 962 EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo)); 963 EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo)); 964 965 /* Standard data source and destination managers: stdio streams. */ 966 /* Caller is responsible for opening the file before and closing after. */ 967 EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile)); 968 EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile)); 969 970 /* Data source and destination managers: memory buffers. */ 971 EXTERN(void) jpeg_mem_dest JPP((j_compress_ptr cinfo, 972 unsigned char ** outbuffer, 973 unsigned long * outsize)); 974 EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo, 975 unsigned char * inbuffer, 976 unsigned long insize)); 977 978 /* Default parameter setup for compression */ 979 EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo)); 980 /* Compression parameter setup aids */ 981 EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo, 982 J_COLOR_SPACE colorspace)); 983 EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo)); 984 EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality, 985 boolean force_baseline)); 986 EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo, 987 int scale_factor, 988 boolean force_baseline)); 989 EXTERN(void) jpeg_default_qtables JPP((j_compress_ptr cinfo, 990 boolean force_baseline)); 991 EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl, 992 const unsigned int *basic_table, 993 int scale_factor, 994 boolean force_baseline)); 995 EXTERN(int) jpeg_quality_scaling JPP((int quality)); 996 EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo)); 997 EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo, 998 boolean suppress)); 999 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo)); 1000 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo)); 1001 1002 /* Main entry points for compression */ 1003 EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo, 1004 boolean write_all_tables)); 1005 EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo, 1006 JSAMPARRAY scanlines, 1007 JDIMENSION num_lines)); 1008 EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo)); 1009 1010 /* Precalculate JPEG dimensions for current compression parameters. */ 1011 EXTERN(void) jpeg_calc_jpeg_dimensions JPP((j_compress_ptr cinfo)); 1012 1013 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */ 1014 EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo, 1015 JSAMPIMAGE data, 1016 JDIMENSION num_lines)); 1017 1018 /* Write a special marker. See libjpeg.txt concerning safe usage. */ 1019 EXTERN(void) jpeg_write_marker 1020 JPP((j_compress_ptr cinfo, int marker, 1021 const JOCTET * dataptr, unsigned int datalen)); 1022 /* Same, but piecemeal. */ 1023 EXTERN(void) jpeg_write_m_header 1024 JPP((j_compress_ptr cinfo, int marker, unsigned int datalen)); 1025 EXTERN(void) jpeg_write_m_byte 1026 JPP((j_compress_ptr cinfo, int val)); 1027 1028 /* Alternate compression function: just write an abbreviated table file */ 1029 EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo)); 1030 1031 /* Decompression startup: read start of JPEG datastream to see what's there */ 1032 EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo, 1033 boolean require_image)); 1034 /* Return value is one of: */ 1035 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */ 1036 #define JPEG_HEADER_OK 1 /* Found valid image datastream */ 1037 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */ 1038 /* If you pass require_image = TRUE (normal case), you need not check for 1039 * a TABLES_ONLY return code; an abbreviated file will cause an error exit. 1040 * JPEG_SUSPENDED is only possible if you use a data source module that can 1041 * give a suspension return (the stdio source module doesn't). 1042 */ 1043 1044 /* Main entry points for decompression */ 1045 EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo)); 1046 EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo, 1047 JSAMPARRAY scanlines, 1048 JDIMENSION max_lines)); 1049 EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo)); 1050 1051 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */ 1052 EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo, 1053 JSAMPIMAGE data, 1054 JDIMENSION max_lines)); 1055 1056 /* Additional entry points for buffered-image mode. */ 1057 EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo)); 1058 EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo, 1059 int scan_number)); 1060 EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo)); 1061 EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo)); 1062 EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo)); 1063 EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo)); 1064 /* Return value is one of: */ 1065 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */ 1066 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */ 1067 #define JPEG_REACHED_EOI 2 /* Reached end of image */ 1068 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */ 1069 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */ 1070 1071 /* Precalculate output dimensions for current decompression parameters. */ 1072 EXTERN(void) jpeg_core_output_dimensions JPP((j_decompress_ptr cinfo)); 1073 EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo)); 1074 1075 /* Control saving of COM and APPn markers into marker_list. */ 1076 EXTERN(void) jpeg_save_markers 1077 JPP((j_decompress_ptr cinfo, int marker_code, 1078 unsigned int length_limit)); 1079 1080 /* Install a special processing method for COM or APPn markers. */ 1081 EXTERN(void) jpeg_set_marker_processor 1082 JPP((j_decompress_ptr cinfo, int marker_code, 1083 jpeg_marker_parser_method routine)); 1084 1085 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */ 1086 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo)); 1087 EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo, 1088 jvirt_barray_ptr * coef_arrays)); 1089 EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo, 1090 j_compress_ptr dstinfo)); 1091 1092 /* If you choose to abort compression or decompression before completing 1093 * jpeg_finish_(de)compress, then you need to clean up to release memory, 1094 * temporary files, etc. You can just call jpeg_destroy_(de)compress 1095 * if you're done with the JPEG object, but if you want to clean it up and 1096 * reuse it, call this: 1097 */ 1098 EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo)); 1099 EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo)); 1100 1101 /* Generic versions of jpeg_abort and jpeg_destroy that work on either 1102 * flavor of JPEG object. These may be more convenient in some places. 1103 */ 1104 EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo)); 1105 EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo)); 1106 1107 /* Default restart-marker-resync procedure for use by data source modules */ 1108 EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo, 1109 int desired)); 1110 1111 1112 /* These marker codes are exported since applications and data source modules 1113 * are likely to want to use them. 1114 */ 1115 1116 #define JPEG_RST0 0xD0 /* RST0 marker code */ 1117 #define JPEG_EOI 0xD9 /* EOI marker code */ 1118 #define JPEG_APP0 0xE0 /* APP0 marker code */ 1119 #define JPEG_COM 0xFE /* COM marker code */ 1120 1121 1122 /* If we have a brain-damaged compiler that emits warnings (or worse, errors) 1123 * for structure definitions that are never filled in, keep it quiet by 1124 * supplying dummy definitions for the various substructures. 1125 */ 1126 1127 #ifdef INCOMPLETE_TYPES_BROKEN 1128 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */ 1129 struct jvirt_sarray_control { long dummy; }; 1130 struct jvirt_barray_control { long dummy; }; 1131 struct jpeg_comp_master { long dummy; }; 1132 struct jpeg_c_main_controller { long dummy; }; 1133 struct jpeg_c_prep_controller { long dummy; }; 1134 struct jpeg_c_coef_controller { long dummy; }; 1135 struct jpeg_marker_writer { long dummy; }; 1136 struct jpeg_color_converter { long dummy; }; 1137 struct jpeg_downsampler { long dummy; }; 1138 struct jpeg_forward_dct { long dummy; }; 1139 struct jpeg_entropy_encoder { long dummy; }; 1140 struct jpeg_decomp_master { long dummy; }; 1141 struct jpeg_d_main_controller { long dummy; }; 1142 struct jpeg_d_coef_controller { long dummy; }; 1143 struct jpeg_d_post_controller { long dummy; }; 1144 struct jpeg_input_controller { long dummy; }; 1145 struct jpeg_marker_reader { long dummy; }; 1146 struct jpeg_entropy_decoder { long dummy; }; 1147 struct jpeg_inverse_dct { long dummy; }; 1148 struct jpeg_upsampler { long dummy; }; 1149 struct jpeg_color_deconverter { long dummy; }; 1150 struct jpeg_color_quantizer { long dummy; }; 1151 #endif /* JPEG_INTERNALS */ 1152 #endif /* INCOMPLETE_TYPES_BROKEN */ 1153 1154 1155 /* 1156 * The JPEG library modules define JPEG_INTERNALS before including this file. 1157 * The internal structure declarations are read only when that is true. 1158 * Applications using the library should not include jpegint.h, but may wish 1159 * to include jerror.h. 1160 */ 1161 1162 #ifdef JPEG_INTERNALS 1163 #include "jpegint.h" /* fetch private declarations */ 1164 #include "jerror.h" /* fetch error codes too */ 1165 #endif 1166 1167 #ifdef __cplusplus 1168 #ifndef DONT_USE_EXTERN_C 1169 } 1170 #endif 1171 #endif 1172 1173 #endif /* JPEGLIB_H */ 1174
