5 * Copyright (C) 1991-1995, Thomas G. Lane.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
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.
37 // JDC: stuff to make mac version compile
38 #define boolean qboolean
61 // TTimo: if LoadJPGBuff returns -1, *pic is the error message
62 extern int LoadJPGBuff(unsigned char *fbuffer, int bufsize, unsigned char **pic, int *width, int *height );
67 * First we include the configuration files that record how this
68 * installation of the JPEG library is set up. jconfig.h can be
69 * generated automatically for many systems. jmorecfg.h contains
70 * manual configuration options that most people need not worry about.
73 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
74 #include "jpeg6/jconfig.h" /* widely used configuration options */
76 #include "jpeg6/jmorecfg.h" /* seldom changed options */
79 /* Version ID for the JPEG library.
80 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
83 #define JPEG_LIB_VERSION 60 /* Version 6 */
86 /* Various constants determining the sizes of things.
87 * All of these are specified by the JPEG standard, so don't change them
88 * if you want to be compatible.
91 #define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
92 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
93 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
94 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
95 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
96 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
97 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
98 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
99 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
100 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
101 * to handle it. We even let you do this from the jconfig.h file. However,
102 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
103 * sometimes emits noncompliant files doesn't mean you should too.
105 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
106 #ifndef D_MAX_BLOCKS_IN_MCU
107 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
111 /* This macro is used to declare a "method", that is, a function pointer.
112 * We want to supply prototype parameters if the compiler can cope.
113 * Note that the arglist parameter must be parenthesized!
116 #ifdef HAVE_PROTOTYPES
117 #define JMETHOD(type,methodname,arglist) type (*methodname) arglist
119 #define JMETHOD(type,methodname,arglist) type (*methodname)()
123 /* Data structures for images (arrays of samples and of DCT coefficients).
124 * On 80x86 machines, the image arrays are too big for near pointers,
125 * but the pointer arrays can fit in near memory.
128 typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
129 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
130 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
132 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
133 typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
134 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
135 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
137 typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
140 /* Types for JPEG compression parameters and working tables. */
143 /* DCT coefficient quantization tables. */
146 /* This field directly represents the contents of a JPEG DQT marker.
147 * Note: the values are always given in zigzag order.
149 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
150 /* This field is used only during compression. It's initialized FALSE when
151 * the table is created, and set TRUE when it's been output to the file.
152 * You could suppress output of a table by setting this to TRUE.
153 * (See jpeg_suppress_tables for an example.)
155 boolean sent_table; /* TRUE when table has been output */
159 /* Huffman coding tables. */
162 /* These two fields directly represent the contents of a JPEG DHT marker */
163 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
164 /* length k bits; bits[0] is unused */
165 UINT8 huffval[256]; /* The symbols, in order of incr code length */
166 /* This field is used only during compression. It's initialized FALSE when
167 * the table is created, and set TRUE when it's been output to the file.
168 * You could suppress output of a table by setting this to TRUE.
169 * (See jpeg_suppress_tables for an example.)
171 boolean sent_table; /* TRUE when table has been output */
175 /* Basic info about one component (color channel). */
178 /* These values are fixed over the whole image. */
179 /* For compression, they must be supplied by parameter setup; */
180 /* for decompression, they are read from the SOF marker. */
181 int component_id; /* identifier for this component (0..255) */
182 int component_index; /* its index in SOF or cinfo->comp_info[] */
183 int h_samp_factor; /* horizontal sampling factor (1..4) */
184 int v_samp_factor; /* vertical sampling factor (1..4) */
185 int quant_tbl_no; /* quantization table selector (0..3) */
186 /* These values may vary between scans. */
187 /* For compression, they must be supplied by parameter setup; */
188 /* for decompression, they are read from the SOS marker. */
189 /* The decompressor output side may not use these variables. */
190 int dc_tbl_no; /* DC entropy table selector (0..3) */
191 int ac_tbl_no; /* AC entropy table selector (0..3) */
193 /* Remaining fields should be treated as private by applications. */
195 /* These values are computed during compression or decompression startup: */
196 /* Component's size in DCT blocks.
197 * Any dummy blocks added to complete an MCU are not counted; therefore
198 * these values do not depend on whether a scan is interleaved or not.
200 JDIMENSION width_in_blocks;
201 JDIMENSION height_in_blocks;
202 /* Size of a DCT block in samples. Always DCTSIZE for compression.
203 * For decompression this is the size of the output from one DCT block,
204 * reflecting any scaling we choose to apply during the IDCT step.
205 * Values of 1,2,4,8 are likely to be supported. Note that different
206 * components may receive different IDCT scalings.
209 /* The downsampled dimensions are the component's actual, unpadded number
210 * of samples at the main buffer (preprocessing/compression interface), thus
211 * downsampled_width = ceil(image_width * Hi/Hmax)
212 * and similarly for height. For decompression, IDCT scaling is included, so
213 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)
215 JDIMENSION downsampled_width; /* actual width in samples */
216 JDIMENSION downsampled_height; /* actual height in samples */
217 /* This flag is used only for decompression. In cases where some of the
218 * components will be ignored (eg grayscale output from YCbCr image),
219 * we can skip most computations for the unused components.
221 boolean component_needed; /* do we need the value of this component? */
223 /* These values are computed before starting a scan of the component. */
224 /* The decompressor output side may not use these variables. */
225 int MCU_width; /* number of blocks per MCU, horizontally */
226 int MCU_height; /* number of blocks per MCU, vertically */
227 int MCU_blocks; /* MCU_width * MCU_height */
228 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_scaled_size */
229 int last_col_width; /* # of non-dummy blocks across in last MCU */
230 int last_row_height; /* # of non-dummy blocks down in last MCU */
232 /* Saved quantization table for component; NULL if none yet saved.
233 * See jdinput.c comments about the need for this information.
234 * This field is not currently used by the compressor.
236 JQUANT_TBL * quant_table;
238 /* Private per-component storage for DCT or IDCT subsystem. */
240 } jpeg_component_info;
243 /* The script for encoding a multiple-scan file is an array of these: */
246 int comps_in_scan; /* number of components encoded in this scan */
247 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
248 int Ss, Se; /* progressive JPEG spectral selection parms */
249 int Ah, Al; /* progressive JPEG successive approx. parms */
253 /* Known color spaces. */
256 JCS_UNKNOWN, /* error/unspecified */
257 JCS_GRAYSCALE, /* monochrome */
258 JCS_RGB, /* red/green/blue */
259 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
260 JCS_CMYK, /* C/M/Y/K */
261 JCS_YCCK /* Y/Cb/Cr/K */
264 /* DCT/IDCT algorithm options. */
267 JDCT_ISLOW, /* slow but accurate integer algorithm */
268 JDCT_IFAST, /* faster, less accurate integer method */
269 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
272 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
273 #define JDCT_DEFAULT JDCT_ISLOW
275 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
276 #define JDCT_FASTEST JDCT_IFAST
279 /* Dithering options for decompression. */
282 JDITHER_NONE, /* no dithering */
283 JDITHER_ORDERED, /* simple ordered dither */
284 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
288 /* Common fields between JPEG compression and decompression master structs. */
290 #define jpeg_common_fields \
291 struct jpeg_error_mgr * err; /* Error handler module */\
292 struct jpeg_memory_mgr * mem; /* Memory manager module */\
293 struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
294 boolean is_decompressor; /* so common code can tell which is which */\
295 int global_state /* for checking call sequence validity */
297 /* Routines that are to be used by both halves of the library are declared
298 * to receive a pointer to this structure. There are no actual instances of
299 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
301 struct jpeg_common_struct {
302 jpeg_common_fields; /* Fields common to both master struct types */
303 /* Additional fields follow in an actual jpeg_compress_struct or
304 * jpeg_decompress_struct. All three structs must agree on these
305 * initial fields! (This would be a lot cleaner in C++.)
309 typedef struct jpeg_common_struct * j_common_ptr;
310 typedef struct jpeg_compress_struct * j_compress_ptr;
311 typedef struct jpeg_decompress_struct * j_decompress_ptr;
314 /* Master record for a compression instance */
316 struct jpeg_compress_struct {
317 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
319 /* Destination for compressed data */
320 struct jpeg_destination_mgr * dest;
322 /* Description of source image --- these fields must be filled in by
323 * outer application before starting compression. in_color_space must
324 * be correct before you can even call jpeg_set_defaults().
327 JDIMENSION image_width; /* input image width */
328 JDIMENSION image_height; /* input image height */
329 int input_components; /* # of color components in input image */
330 J_COLOR_SPACE in_color_space; /* colorspace of input image */
332 double input_gamma; /* image gamma of input image */
334 /* Compression parameters --- these fields must be set before calling
335 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
336 * initialize everything to reasonable defaults, then changing anything
337 * the application specifically wants to change. That way you won't get
338 * burnt when new parameters are added. Also note that there are several
339 * helper routines to simplify changing parameters.
342 int data_precision; /* bits of precision in image data */
344 int num_components; /* # of color components in JPEG image */
345 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
347 jpeg_component_info * comp_info;
348 /* comp_info[i] describes component that appears i'th in SOF */
350 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
351 /* ptrs to coefficient quantization tables, or NULL if not defined */
353 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
354 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
355 /* ptrs to Huffman coding tables, or NULL if not defined */
357 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
358 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
359 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
361 int num_scans; /* # of entries in scan_info array */
362 const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
363 /* The default value of scan_info is NULL, which causes a single-scan
364 * sequential JPEG file to be emitted. To create a multi-scan file,
365 * set num_scans and scan_info to point to an array of scan definitions.
368 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
369 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
370 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
371 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
372 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
373 J_DCT_METHOD dct_method; /* DCT algorithm selector */
375 /* The restart interval can be specified in absolute MCUs by setting
376 * restart_interval, or in MCU rows by setting restart_in_rows
377 * (in which case the correct restart_interval will be figured
380 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
381 int restart_in_rows; /* if > 0, MCU rows per restart interval */
383 /* Parameters controlling emission of special markers. */
385 boolean write_JFIF_header; /* should a JFIF marker be written? */
386 /* These three values are not used by the JPEG code, merely copied */
387 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
388 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
389 /* ratio is defined by X_density/Y_density even when density_unit=0. */
390 UINT8 density_unit; /* JFIF code for pixel size units */
391 UINT16 X_density; /* Horizontal pixel density */
392 UINT16 Y_density; /* Vertical pixel density */
393 boolean write_Adobe_marker; /* should an Adobe marker be written? */
395 /* State variable: index of next scanline to be written to
396 * jpeg_write_scanlines(). Application may use this to control its
397 * processing loop, e.g., "while (next_scanline < image_height)".
400 JDIMENSION next_scanline; /* 0 .. image_height-1 */
402 /* Remaining fields are known throughout compressor, but generally
403 * should not be touched by a surrounding application.
407 * These fields are computed during compression startup
409 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
410 int max_h_samp_factor; /* largest h_samp_factor */
411 int max_v_samp_factor; /* largest v_samp_factor */
413 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
414 /* The coefficient controller receives data in units of MCU rows as defined
415 * for fully interleaved scans (whether the JPEG file is interleaved or not).
416 * There are v_samp_factor * DCTSIZE sample rows of each component in an
417 * "iMCU" (interleaved MCU) row.
421 * These fields are valid during any one scan.
422 * They describe the components and MCUs actually appearing in the scan.
424 int comps_in_scan; /* # of JPEG components in this scan */
425 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
426 /* *cur_comp_info[i] describes component that appears i'th in SOS */
428 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
429 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
431 int blocks_in_MCU; /* # of DCT blocks per MCU */
432 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
433 /* MCU_membership[i] is index in cur_comp_info of component owning */
434 /* i'th block in an MCU */
436 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
439 * Links to compression subobjects (methods and private variables of modules)
441 struct jpeg_comp_master * master;
442 struct jpeg_c_main_controller * main;
443 struct jpeg_c_prep_controller * prep;
444 struct jpeg_c_coef_controller * coef;
445 struct jpeg_marker_writer * marker;
446 struct jpeg_color_converter * cconvert;
447 struct jpeg_downsampler * downsample;
448 struct jpeg_forward_dct * fdct;
449 struct jpeg_entropy_encoder * entropy;
453 /* Master record for a decompression instance */
455 struct jpeg_decompress_struct {
456 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
458 /* Source of compressed data */
459 struct jpeg_source_mgr * src;
461 /* Basic description of image --- filled in by jpeg_read_header(). */
462 /* Application may inspect these values to decide how to process image. */
464 JDIMENSION image_width; /* nominal image width (from SOF marker) */
465 JDIMENSION image_height; /* nominal image height */
466 int num_components; /* # of color components in JPEG image */
467 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
469 /* Decompression processing parameters --- these fields must be set before
470 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
471 * them to default values.
474 J_COLOR_SPACE out_color_space; /* colorspace for output */
476 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
478 double output_gamma; /* image gamma wanted in output */
480 boolean buffered_image; /* TRUE=multiple output passes */
481 boolean raw_data_out; /* TRUE=downsampled data wanted */
483 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
484 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
485 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
487 boolean quantize_colors; /* TRUE=colormapped output wanted */
488 /* the following are ignored if not quantize_colors: */
489 J_DITHER_MODE dither_mode; /* type of color dithering to use */
490 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
491 int desired_number_of_colors; /* max # colors to use in created colormap */
492 /* these are significant only in buffered-image mode: */
493 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
494 boolean enable_external_quant;/* enable future use of external colormap */
495 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
497 /* Description of actual output image that will be returned to application.
498 * These fields are computed by jpeg_start_decompress().
499 * You can also use jpeg_calc_output_dimensions() to determine these values
500 * in advance of calling jpeg_start_decompress().
503 JDIMENSION output_width; /* scaled image width */
504 JDIMENSION output_height; /* scaled image height */
505 int out_color_components; /* # of color components in out_color_space */
506 int output_components; /* # of color components returned */
507 /* output_components is 1 (a colormap index) when quantizing colors;
508 * otherwise it equals out_color_components.
510 int rec_outbuf_height; /* min recommended height of scanline buffer */
511 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
512 * high, space and time will be wasted due to unnecessary data copying.
513 * Usually rec_outbuf_height will be 1 or 2, at most 4.
516 /* When quantizing colors, the output colormap is described by these fields.
517 * The application can supply a colormap by setting colormap non-NULL before
518 * calling jpeg_start_decompress; otherwise a colormap is created during
519 * jpeg_start_decompress or jpeg_start_output.
520 * The map has out_color_components rows and actual_number_of_colors columns.
522 int actual_number_of_colors; /* number of entries in use */
523 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
525 /* State variables: these variables indicate the progress of decompression.
526 * The application may examine these but must not modify them.
529 /* Row index of next scanline to be read from jpeg_read_scanlines().
530 * Application may use this to control its processing loop, e.g.,
531 * "while (output_scanline < output_height)".
533 JDIMENSION output_scanline; /* 0 .. output_height-1 */
535 /* Current input scan number and number of iMCU rows completed in scan.
536 * These indicate the progress of the decompressor input side.
538 int input_scan_number; /* Number of SOS markers seen so far */
539 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
541 /* The "output scan number" is the notional scan being displayed by the
542 * output side. The decompressor will not allow output scan/row number
543 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
545 int output_scan_number; /* Nominal scan number being displayed */
546 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
548 /* Current progression status. coef_bits[c][i] indicates the precision
549 * with which component c's DCT coefficient i (in zigzag order) is known.
550 * It is -1 when no data has yet been received, otherwise it is the point
551 * transform (shift) value for the most recent scan of the coefficient
552 * (thus, 0 at completion of the progression).
553 * This pointer is NULL when reading a non-progressive file.
555 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
557 /* Internal JPEG parameters --- the application usually need not look at
558 * these fields. Note that the decompressor output side may not use
559 * any parameters that can change between scans.
562 /* Quantization and Huffman tables are carried forward across input
563 * datastreams when processing abbreviated JPEG datastreams.
566 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
567 /* ptrs to coefficient quantization tables, or NULL if not defined */
569 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
570 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
571 /* ptrs to Huffman coding tables, or NULL if not defined */
573 /* These parameters are never carried across datastreams, since they
574 * are given in SOF/SOS markers or defined to be reset by SOI.
577 int data_precision; /* bits of precision in image data */
579 jpeg_component_info * comp_info;
580 /* comp_info[i] describes component that appears i'th in SOF */
582 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
583 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
585 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
586 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
587 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
589 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
591 /* These fields record data obtained from optional markers recognized by
594 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
595 /* Data copied from JFIF marker: */
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 */
602 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
604 /* Remaining fields are known throughout decompressor, but generally
605 * should not be touched by a surrounding application.
609 * These fields are computed during decompression startup
611 int max_h_samp_factor; /* largest h_samp_factor */
612 int max_v_samp_factor; /* largest v_samp_factor */
614 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */
616 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
617 /* The coefficient controller's input and output progress is measured in
618 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
619 * in fully interleaved JPEG scans, but are used whether the scan is
620 * interleaved or not. We define an iMCU row as v_samp_factor DCT block
621 * rows of each component. Therefore, the IDCT output contains
622 * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
625 JSAMPLE * sample_range_limit; /* table for fast range-limiting */
628 * These fields are valid during any one scan.
629 * They describe the components and MCUs actually appearing in the scan.
630 * Note that the decompressor output side must not use these fields.
632 int comps_in_scan; /* # of JPEG components in this scan */
633 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
634 /* *cur_comp_info[i] describes component that appears i'th in SOS */
636 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
637 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
639 int blocks_in_MCU; /* # of DCT blocks per MCU */
640 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
641 /* MCU_membership[i] is index in cur_comp_info of component owning */
642 /* i'th block in an MCU */
644 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
646 /* This field is shared between entropy decoder and marker parser.
647 * It is either zero or the code of a JPEG marker that has been
648 * read from the data source, but has not yet been processed.
653 * Links to decompression subobjects (methods, private variables of modules)
655 struct jpeg_decomp_master * master;
656 struct jpeg_d_main_controller * main;
657 struct jpeg_d_coef_controller * coef;
658 struct jpeg_d_post_controller * post;
659 struct jpeg_input_controller * inputctl;
660 struct jpeg_marker_reader * marker;
661 struct jpeg_entropy_decoder * entropy;
662 struct jpeg_inverse_dct * idct;
663 struct jpeg_upsampler * upsample;
664 struct jpeg_color_deconverter * cconvert;
665 struct jpeg_color_quantizer * cquantize;
669 /* "Object" declarations for JPEG modules that may be supplied or called
670 * directly by the surrounding application.
671 * As with all objects in the JPEG library, these structs only define the
672 * publicly visible methods and state variables of a module. Additional
673 * private fields may exist after the public ones.
677 /* Error handler object */
679 struct jpeg_error_mgr {
680 /* Error exit handler: does not return to caller */
681 JMETHOD(void, error_exit, (j_common_ptr cinfo));
682 /* Conditionally emit a trace or warning message */
683 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
684 /* Routine that actually outputs a trace or error message */
685 JMETHOD(void, output_message, (j_common_ptr cinfo));
686 /* Format a message string for the most recent JPEG error or message */
687 JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
688 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
689 /* Reset error state variables at start of a new image */
690 JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
692 /* The message ID code and any parameters are saved here.
693 * A message can have one string parameter or up to 8 int parameters.
696 #define JMSG_STR_PARM_MAX 80
699 char s[JMSG_STR_PARM_MAX];
702 /* Standard state variables for error facility */
704 int trace_level; /* max msg_level that will be displayed */
706 /* For recoverable corrupt-data errors, we emit a warning message,
707 * but keep going unless emit_message chooses to abort. emit_message
708 * should count warnings in num_warnings. The surrounding application
709 * can check for bad data by seeing if num_warnings is nonzero at the
712 long num_warnings; /* number of corrupt-data warnings */
714 /* These fields point to the table(s) of error message strings.
715 * An application can change the table pointer to switch to a different
716 * message list (typically, to change the language in which errors are
717 * reported). Some applications may wish to add additional error codes
718 * that will be handled by the JPEG library error mechanism; the second
719 * table pointer is used for this purpose.
721 * First table includes all errors generated by JPEG library itself.
722 * Error code 0 is reserved for a "no such error string" message.
724 const char * const * jpeg_message_table; /* Library errors */
725 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
726 /* Second table can be added by application (see cjpeg/djpeg for example).
727 * It contains strings numbered first_addon_message..last_addon_message.
729 const char * const * addon_message_table; /* Non-library errors */
730 int first_addon_message; /* code for first string in addon table */
731 int last_addon_message; /* code for last string in addon table */
735 /* Progress monitor object */
737 struct jpeg_progress_mgr {
738 JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
740 long pass_counter; /* work units completed in this pass */
741 long pass_limit; /* total number of work units in this pass */
742 int completed_passes; /* passes completed so far */
743 int total_passes; /* total number of passes expected */
747 /* Data destination object for compression */
749 struct jpeg_destination_mgr {
750 JOCTET * next_output_byte; /* => next byte to write in buffer */
751 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
753 JMETHOD(void, init_destination, (j_compress_ptr cinfo));
754 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
755 JMETHOD(void, term_destination, (j_compress_ptr cinfo));
759 /* Data source object for decompression */
761 struct jpeg_source_mgr {
762 const JOCTET * next_input_byte; /* => next byte to read from buffer */
763 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
765 JMETHOD(void, init_source, (j_decompress_ptr cinfo));
766 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
767 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
768 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
769 JMETHOD(void, term_source, (j_decompress_ptr cinfo));
773 /* Memory manager object.
774 * Allocates "small" objects (a few K total), "large" objects (tens of K),
775 * and "really big" objects (virtual arrays with backing store if needed).
776 * The memory manager does not allow individual objects to be freed; rather,
777 * each created object is assigned to a pool, and whole pools can be freed
778 * at once. This is faster and more convenient than remembering exactly what
779 * to free, especially where malloc()/free() are not too speedy.
780 * NB: alloc routines never return NULL. They exit to error_exit if not
784 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
785 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
786 #define JPOOL_NUMPOOLS 2
788 typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
789 typedef struct jvirt_barray_control * jvirt_barray_ptr;
792 struct jpeg_memory_mgr {
793 /* Method pointers */
794 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
795 size_t sizeofobject));
796 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
797 size_t sizeofobject));
798 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
799 JDIMENSION samplesperrow,
800 JDIMENSION numrows));
801 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
802 JDIMENSION blocksperrow,
803 JDIMENSION numrows));
804 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
807 JDIMENSION samplesperrow,
809 JDIMENSION maxaccess));
810 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
813 JDIMENSION blocksperrow,
815 JDIMENSION maxaccess));
816 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
817 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
818 jvirt_sarray_ptr ptr,
819 JDIMENSION start_row,
822 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
823 jvirt_barray_ptr ptr,
824 JDIMENSION start_row,
827 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
828 JMETHOD(void, self_destruct, (j_common_ptr cinfo));
830 /* Limit on memory allocation for this JPEG object. (Note that this is
831 * merely advisory, not a guaranteed maximum; it only affects the space
832 * used for virtual-array buffers.) May be changed by outer application
833 * after creating the JPEG object.
835 long max_memory_to_use;
839 /* Routine signature for application-supplied marker processing methods.
840 * Need not pass marker code since it is stored in cinfo->unread_marker.
842 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
845 /* Declarations for routines called by application.
846 * The JPP macro hides prototype parameters from compilers that can't cope.
847 * Note JPP requires double parentheses.
850 #ifdef HAVE_PROTOTYPES
851 #define JPP(arglist) arglist
853 #define JPP(arglist) ()
857 /* Short forms of external names for systems with brain-damaged linkers.
858 * We shorten external names to be unique in the first six letters, which
859 * is good enough for all known systems.
860 * (If your compiler itself needs names to be unique in less than 15
861 * characters, you are out of luck. Get a better compiler.)
864 #ifdef NEED_SHORT_EXTERNAL_NAMES
865 #define jpeg_std_error jStdError
866 #define jpeg_create_compress jCreaCompress
867 #define jpeg_create_decompress jCreaDecompress
868 #define jpeg_destroy_compress jDestCompress
869 #define jpeg_destroy_decompress jDestDecompress
870 #define jpeg_stdio_dest jStdDest
871 #define jpeg_stdio_src jStdSrc
872 #define jpeg_set_defaults jSetDefaults
873 #define jpeg_set_colorspace jSetColorspace
874 #define jpeg_default_colorspace jDefColorspace
875 #define jpeg_set_quality jSetQuality
876 #define jpeg_set_linear_quality jSetLQuality
877 #define jpeg_add_quant_table jAddQuantTable
878 #define jpeg_quality_scaling jQualityScaling
879 #define jpeg_simple_progression jSimProgress
880 #define jpeg_suppress_tables jSuppressTables
881 #define jpeg_alloc_quant_table jAlcQTable
882 #define jpeg_alloc_huff_table jAlcHTable
883 #define jpeg_start_compress jStrtCompress
884 #define jpeg_write_scanlines jWrtScanlines
885 #define jpeg_finish_compress jFinCompress
886 #define jpeg_write_raw_data jWrtRawData
887 #define jpeg_write_marker jWrtMarker
888 #define jpeg_write_tables jWrtTables
889 #define jpeg_read_header jReadHeader
890 #define jpeg_start_decompress jStrtDecompress
891 #define jpeg_read_scanlines jReadScanlines
892 #define jpeg_finish_decompress jFinDecompress
893 #define jpeg_read_raw_data jReadRawData
894 #define jpeg_has_multiple_scans jHasMultScn
895 #define jpeg_start_output jStrtOutput
896 #define jpeg_finish_output jFinOutput
897 #define jpeg_input_complete jInComplete
898 #define jpeg_new_colormap jNewCMap
899 #define jpeg_consume_input jConsumeInput
900 #define jpeg_calc_output_dimensions jCalcDimensions
901 #define jpeg_set_marker_processor jSetMarker
902 #define jpeg_read_coefficients jReadCoefs
903 #define jpeg_write_coefficients jWrtCoefs
904 #define jpeg_copy_critical_parameters jCopyCrit
905 #define jpeg_abort_compress jAbrtCompress
906 #define jpeg_abort_decompress jAbrtDecompress
907 #define jpeg_abort jAbort
908 #define jpeg_destroy jDestroy
909 #define jpeg_resync_to_restart jResyncRestart
910 #endif /* NEED_SHORT_EXTERNAL_NAMES */
913 /* Default error-management setup */
914 EXTERN struct jpeg_error_mgr *jpeg_std_error JPP((struct jpeg_error_mgr *err));
916 /* Initialization and destruction of JPEG compression objects */
917 /* NB: you must set up the error-manager BEFORE calling jpeg_create_xxx */
918 EXTERN void jpeg_create_compress JPP((j_compress_ptr cinfo));
919 EXTERN void jpeg_create_decompress JPP((j_decompress_ptr cinfo));
920 EXTERN void jpeg_destroy_compress JPP((j_compress_ptr cinfo));
921 EXTERN void jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
923 /* Standard data source and destination managers: stdio streams. */
924 /* Caller is responsible for opening the file before and closing after. */
925 EXTERN void jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
926 EXTERN void jpeg_stdio_src JPP((j_decompress_ptr cinfo, unsigned char *infile, int bufsize));
928 /* Default parameter setup for compression */
929 EXTERN void jpeg_set_defaults JPP((j_compress_ptr cinfo));
930 /* Compression parameter setup aids */
931 EXTERN void jpeg_set_colorspace JPP((j_compress_ptr cinfo,
932 J_COLOR_SPACE colorspace));
933 EXTERN void jpeg_default_colorspace JPP((j_compress_ptr cinfo));
934 EXTERN void jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
935 boolean force_baseline));
936 EXTERN void jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
938 boolean force_baseline));
939 EXTERN void jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
940 const unsigned int *basic_table,
942 boolean force_baseline));
943 EXTERN int jpeg_quality_scaling JPP((int quality));
944 EXTERN void jpeg_simple_progression JPP((j_compress_ptr cinfo));
945 EXTERN void jpeg_suppress_tables JPP((j_compress_ptr cinfo,
947 EXTERN JQUANT_TBL * jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
948 EXTERN JHUFF_TBL * jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
950 /* Main entry points for compression */
951 EXTERN void jpeg_start_compress JPP((j_compress_ptr cinfo,
952 boolean write_all_tables));
953 EXTERN JDIMENSION jpeg_write_scanlines JPP((j_compress_ptr cinfo,
954 JSAMPARRAY scanlines,
955 JDIMENSION num_lines));
956 EXTERN void jpeg_finish_compress JPP((j_compress_ptr cinfo));
958 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
959 EXTERN JDIMENSION jpeg_write_raw_data JPP((j_compress_ptr cinfo,
961 JDIMENSION num_lines));
963 /* Write a special marker. See libjpeg.doc concerning safe usage. */
964 EXTERN void jpeg_write_marker JPP((j_compress_ptr cinfo, int marker,
965 const JOCTET *dataptr, unsigned int datalen));
967 /* Alternate compression function: just write an abbreviated table file */
968 EXTERN void jpeg_write_tables JPP((j_compress_ptr cinfo));
970 /* Decompression startup: read start of JPEG datastream to see what's there */
971 EXTERN int jpeg_read_header JPP((j_decompress_ptr cinfo,
972 boolean require_image));
973 /* Return value is one of: */
974 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
975 #define JPEG_HEADER_OK 1 /* Found valid image datastream */
976 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
977 /* If you pass require_image = TRUE (normal case), you need not check for
978 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
979 * JPEG_SUSPENDED is only possible if you use a data source module that can
980 * give a suspension return (the stdio source module doesn't).
983 /* Main entry points for decompression */
984 EXTERN boolean jpeg_start_decompress JPP((j_decompress_ptr cinfo));
985 EXTERN JDIMENSION jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
986 JSAMPARRAY scanlines,
987 JDIMENSION max_lines));
988 EXTERN boolean jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
990 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
991 EXTERN JDIMENSION jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
993 JDIMENSION max_lines));
995 /* Additional entry points for buffered-image mode. */
996 EXTERN boolean jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
997 EXTERN boolean jpeg_start_output JPP((j_decompress_ptr cinfo,
999 EXTERN boolean jpeg_finish_output JPP((j_decompress_ptr cinfo));
1000 EXTERN boolean jpeg_input_complete JPP((j_decompress_ptr cinfo));
1001 EXTERN void jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1002 EXTERN int jpeg_consume_input JPP((j_decompress_ptr cinfo));
1003 /* Return value is one of: */
1004 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1005 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1006 #define JPEG_REACHED_EOI 2 /* Reached end of image */
1007 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1008 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1010 /* Precalculate output dimensions for current decompression parameters. */
1011 EXTERN void jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1013 /* Install a special processing method for COM or APPn markers. */
1014 EXTERN void jpeg_set_marker_processor JPP((j_decompress_ptr cinfo,
1016 jpeg_marker_parser_method routine));
1018 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1019 EXTERN jvirt_barray_ptr * jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1020 EXTERN void jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1021 jvirt_barray_ptr * coef_arrays));
1022 EXTERN void jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1023 j_compress_ptr dstinfo));
1025 /* If you choose to abort compression or decompression before completing
1026 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1027 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1028 * if you're done with the JPEG object, but if you want to clean it up and
1029 * reuse it, call this:
1031 EXTERN void jpeg_abort_compress JPP((j_compress_ptr cinfo));
1032 EXTERN void jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1034 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1035 * flavor of JPEG object. These may be more convenient in some places.
1037 EXTERN void jpeg_abort JPP((j_common_ptr cinfo));
1038 EXTERN void jpeg_destroy JPP((j_common_ptr cinfo));
1040 /* Default restart-marker-resync procedure for use by data source modules */
1041 EXTERN boolean jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1045 /* These marker codes are exported since applications and data source modules
1046 * are likely to want to use them.
1049 #define JPEG_RST0 0xD0 /* RST0 marker code */
1050 #define JPEG_EOI 0xD9 /* EOI marker code */
1051 #define JPEG_APP0 0xE0 /* APP0 marker code */
1052 #define JPEG_COM 0xFE /* COM marker code */
1055 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1056 * for structure definitions that are never filled in, keep it quiet by
1057 * supplying dummy definitions for the various substructures.
1060 #ifdef INCOMPLETE_TYPES_BROKEN
1061 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1062 struct jvirt_sarray_control { long dummy; };
1063 struct jvirt_barray_control { long dummy; };
1064 struct jpeg_comp_master { long dummy; };
1065 struct jpeg_c_main_controller { long dummy; };
1066 struct jpeg_c_prep_controller { long dummy; };
1067 struct jpeg_c_coef_controller { long dummy; };
1068 struct jpeg_marker_writer { long dummy; };
1069 struct jpeg_color_converter { long dummy; };
1070 struct jpeg_downsampler { long dummy; };
1071 struct jpeg_forward_dct { long dummy; };
1072 struct jpeg_entropy_encoder { long dummy; };
1073 struct jpeg_decomp_master { long dummy; };
1074 struct jpeg_d_main_controller { long dummy; };
1075 struct jpeg_d_coef_controller { long dummy; };
1076 struct jpeg_d_post_controller { long dummy; };
1077 struct jpeg_input_controller { long dummy; };
1078 struct jpeg_marker_reader { long dummy; };
1079 struct jpeg_entropy_decoder { long dummy; };
1080 struct jpeg_inverse_dct { long dummy; };
1081 struct jpeg_upsampler { long dummy; };
1082 struct jpeg_color_deconverter { long dummy; };
1083 struct jpeg_color_quantizer { long dummy; };
1084 #endif /* JPEG_INTERNALS */
1085 #endif /* INCOMPLETE_TYPES_BROKEN */
1089 * The JPEG library modules define JPEG_INTERNALS before including this file.
1090 * The internal structure declarations are read only when that is true.
1091 * Applications using the library should not include jpegint.h, but may wish
1092 * to include jerror.h.
1095 #ifdef JPEG_INTERNALS
1096 #include "jpegint.h" /* fetch private declarations */
1097 #include "jerror.h" /* fetch error codes too */
1104 #endif /* JPEGLIB_H */