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.
32 // JDC: stuff to make mac version compile
33 #define boolean qboolean
60 // TTimo: if LoadJPGBuff returns -1, *pic is the error message
61 extern int LoadJPGBuff(unsigned char *fbuffer, int bufsize, unsigned char **pic, int *width, int *height );
66 * First we include the configuration files that record how this
67 * installation of the JPEG library is set up. jconfig.h can be
68 * generated automatically for many systems. jmorecfg.h contains
69 * manual configuration options that most people need not worry about.
72 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
73 #include "jpeg6/jconfig.h" /* widely used configuration options */
75 #include "jpeg6/jmorecfg.h" /* seldom changed options */
78 /* Version ID for the JPEG library.
79 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
82 #define JPEG_LIB_VERSION 60 /* Version 6 */
85 /* Various constants determining the sizes of things.
86 * All of these are specified by the JPEG standard, so don't change them
87 * if you want to be compatible.
90 #define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
91 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
92 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
93 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
94 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
95 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
96 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
97 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
98 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
99 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
100 * to handle it. We even let you do this from the jconfig.h file. However,
101 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
102 * sometimes emits noncompliant files doesn't mean you should too.
104 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
105 #ifndef D_MAX_BLOCKS_IN_MCU
106 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
110 /* This macro is used to declare a "method", that is, a function pointer.
111 * We want to supply prototype parameters if the compiler can cope.
112 * Note that the arglist parameter must be parenthesized!
115 #ifdef HAVE_PROTOTYPES
116 #define JMETHOD(type,methodname,arglist) type (*methodname) arglist
118 #define JMETHOD(type,methodname,arglist) type (*methodname)()
122 /* Data structures for images (arrays of samples and of DCT coefficients).
123 * On 80x86 machines, the image arrays are too big for near pointers,
124 * but the pointer arrays can fit in near memory.
127 typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
128 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
129 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
131 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
132 typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
133 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
134 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
136 typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
139 /* Types for JPEG compression parameters and working tables. */
142 /* DCT coefficient quantization tables. */
145 /* This field directly represents the contents of a JPEG DQT marker.
146 * Note: the values are always given in zigzag order.
148 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
149 /* This field is used only during compression. It's initialized FALSE when
150 * the table is created, and set TRUE when it's been output to the file.
151 * You could suppress output of a table by setting this to TRUE.
152 * (See jpeg_suppress_tables for an example.)
154 boolean sent_table; /* TRUE when table has been output */
158 /* Huffman coding tables. */
161 /* These two fields directly represent the contents of a JPEG DHT marker */
162 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
163 /* length k bits; bits[0] is unused */
164 UINT8 huffval[256]; /* The symbols, in order of incr code length */
165 /* This field is used only during compression. It's initialized FALSE when
166 * the table is created, and set TRUE when it's been output to the file.
167 * You could suppress output of a table by setting this to TRUE.
168 * (See jpeg_suppress_tables for an example.)
170 boolean sent_table; /* TRUE when table has been output */
174 /* Basic info about one component (color channel). */
177 /* These values are fixed over the whole image. */
178 /* For compression, they must be supplied by parameter setup; */
179 /* for decompression, they are read from the SOF marker. */
180 int component_id; /* identifier for this component (0..255) */
181 int component_index; /* its index in SOF or cinfo->comp_info[] */
182 int h_samp_factor; /* horizontal sampling factor (1..4) */
183 int v_samp_factor; /* vertical sampling factor (1..4) */
184 int quant_tbl_no; /* quantization table selector (0..3) */
185 /* These values may vary between scans. */
186 /* For compression, they must be supplied by parameter setup; */
187 /* for decompression, they are read from the SOS marker. */
188 /* The decompressor output side may not use these variables. */
189 int dc_tbl_no; /* DC entropy table selector (0..3) */
190 int ac_tbl_no; /* AC entropy table selector (0..3) */
192 /* Remaining fields should be treated as private by applications. */
194 /* These values are computed during compression or decompression startup: */
195 /* Component's size in DCT blocks.
196 * Any dummy blocks added to complete an MCU are not counted; therefore
197 * these values do not depend on whether a scan is interleaved or not.
199 JDIMENSION width_in_blocks;
200 JDIMENSION height_in_blocks;
201 /* Size of a DCT block in samples. Always DCTSIZE for compression.
202 * For decompression this is the size of the output from one DCT block,
203 * reflecting any scaling we choose to apply during the IDCT step.
204 * Values of 1,2,4,8 are likely to be supported. Note that different
205 * components may receive different IDCT scalings.
208 /* The downsampled dimensions are the component's actual, unpadded number
209 * of samples at the main buffer (preprocessing/compression interface), thus
210 * downsampled_width = ceil(image_width * Hi/Hmax)
211 * and similarly for height. For decompression, IDCT scaling is included, so
212 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)
214 JDIMENSION downsampled_width; /* actual width in samples */
215 JDIMENSION downsampled_height; /* actual height in samples */
216 /* This flag is used only for decompression. In cases where some of the
217 * components will be ignored (eg grayscale output from YCbCr image),
218 * we can skip most computations for the unused components.
220 boolean component_needed; /* do we need the value of this component? */
222 /* These values are computed before starting a scan of the component. */
223 /* The decompressor output side may not use these variables. */
224 int MCU_width; /* number of blocks per MCU, horizontally */
225 int MCU_height; /* number of blocks per MCU, vertically */
226 int MCU_blocks; /* MCU_width * MCU_height */
227 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_scaled_size */
228 int last_col_width; /* # of non-dummy blocks across in last MCU */
229 int last_row_height; /* # of non-dummy blocks down in last MCU */
231 /* Saved quantization table for component; NULL if none yet saved.
232 * See jdinput.c comments about the need for this information.
233 * This field is not currently used by the compressor.
235 JQUANT_TBL * quant_table;
237 /* Private per-component storage for DCT or IDCT subsystem. */
239 } jpeg_component_info;
242 /* The script for encoding a multiple-scan file is an array of these: */
245 int comps_in_scan; /* number of components encoded in this scan */
246 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
247 int Ss, Se; /* progressive JPEG spectral selection parms */
248 int Ah, Al; /* progressive JPEG successive approx. parms */
252 /* Known color spaces. */
255 JCS_UNKNOWN, /* error/unspecified */
256 JCS_GRAYSCALE, /* monochrome */
257 JCS_RGB, /* red/green/blue */
258 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
259 JCS_CMYK, /* C/M/Y/K */
260 JCS_YCCK /* Y/Cb/Cr/K */
263 /* DCT/IDCT algorithm options. */
266 JDCT_ISLOW, /* slow but accurate integer algorithm */
267 JDCT_IFAST, /* faster, less accurate integer method */
268 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
271 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
272 #define JDCT_DEFAULT JDCT_ISLOW
274 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
275 #define JDCT_FASTEST JDCT_IFAST
278 /* Dithering options for decompression. */
281 JDITHER_NONE, /* no dithering */
282 JDITHER_ORDERED, /* simple ordered dither */
283 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
287 /* Common fields between JPEG compression and decompression master structs. */
289 #define jpeg_common_fields \
290 struct jpeg_error_mgr * err; /* Error handler module */\
291 struct jpeg_memory_mgr * mem; /* Memory manager module */\
292 struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
293 boolean is_decompressor; /* so common code can tell which is which */\
294 int global_state /* for checking call sequence validity */
296 /* Routines that are to be used by both halves of the library are declared
297 * to receive a pointer to this structure. There are no actual instances of
298 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
300 struct jpeg_common_struct {
301 jpeg_common_fields; /* Fields common to both master struct types */
302 /* Additional fields follow in an actual jpeg_compress_struct or
303 * jpeg_decompress_struct. All three structs must agree on these
304 * initial fields! (This would be a lot cleaner in C++.)
308 typedef struct jpeg_common_struct * j_common_ptr;
309 typedef struct jpeg_compress_struct * j_compress_ptr;
310 typedef struct jpeg_decompress_struct * j_decompress_ptr;
313 /* Master record for a compression instance */
315 struct jpeg_compress_struct {
316 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
318 /* Destination for compressed data */
319 struct jpeg_destination_mgr * dest;
321 /* Description of source image --- these fields must be filled in by
322 * outer application before starting compression. in_color_space must
323 * be correct before you can even call jpeg_set_defaults().
326 JDIMENSION image_width; /* input image width */
327 JDIMENSION image_height; /* input image height */
328 int input_components; /* # of color components in input image */
329 J_COLOR_SPACE in_color_space; /* colorspace of input image */
331 double input_gamma; /* image gamma of input image */
333 /* Compression parameters --- these fields must be set before calling
334 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
335 * initialize everything to reasonable defaults, then changing anything
336 * the application specifically wants to change. That way you won't get
337 * burnt when new parameters are added. Also note that there are several
338 * helper routines to simplify changing parameters.
341 int data_precision; /* bits of precision in image data */
343 int num_components; /* # of color components in JPEG image */
344 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
346 jpeg_component_info * comp_info;
347 /* comp_info[i] describes component that appears i'th in SOF */
349 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
350 /* ptrs to coefficient quantization tables, or NULL if not defined */
352 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
353 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
354 /* ptrs to Huffman coding tables, or NULL if not defined */
356 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
357 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
358 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
360 int num_scans; /* # of entries in scan_info array */
361 const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
362 /* The default value of scan_info is NULL, which causes a single-scan
363 * sequential JPEG file to be emitted. To create a multi-scan file,
364 * set num_scans and scan_info to point to an array of scan definitions.
367 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
368 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
369 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
370 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
371 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
372 J_DCT_METHOD dct_method; /* DCT algorithm selector */
374 /* The restart interval can be specified in absolute MCUs by setting
375 * restart_interval, or in MCU rows by setting restart_in_rows
376 * (in which case the correct restart_interval will be figured
379 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
380 int restart_in_rows; /* if > 0, MCU rows per restart interval */
382 /* Parameters controlling emission of special markers. */
384 boolean write_JFIF_header; /* should a JFIF marker be written? */
385 /* These three values are not used by the JPEG code, merely copied */
386 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
387 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
388 /* ratio is defined by X_density/Y_density even when density_unit=0. */
389 UINT8 density_unit; /* JFIF code for pixel size units */
390 UINT16 X_density; /* Horizontal pixel density */
391 UINT16 Y_density; /* Vertical pixel density */
392 boolean write_Adobe_marker; /* should an Adobe marker be written? */
394 /* State variable: index of next scanline to be written to
395 * jpeg_write_scanlines(). Application may use this to control its
396 * processing loop, e.g., "while (next_scanline < image_height)".
399 JDIMENSION next_scanline; /* 0 .. image_height-1 */
401 /* Remaining fields are known throughout compressor, but generally
402 * should not be touched by a surrounding application.
406 * These fields are computed during compression startup
408 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
409 int max_h_samp_factor; /* largest h_samp_factor */
410 int max_v_samp_factor; /* largest v_samp_factor */
412 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
413 /* The coefficient controller receives data in units of MCU rows as defined
414 * for fully interleaved scans (whether the JPEG file is interleaved or not).
415 * There are v_samp_factor * DCTSIZE sample rows of each component in an
416 * "iMCU" (interleaved MCU) row.
420 * These fields are valid during any one scan.
421 * They describe the components and MCUs actually appearing in the scan.
423 int comps_in_scan; /* # of JPEG components in this scan */
424 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
425 /* *cur_comp_info[i] describes component that appears i'th in SOS */
427 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
428 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
430 int blocks_in_MCU; /* # of DCT blocks per MCU */
431 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
432 /* MCU_membership[i] is index in cur_comp_info of component owning */
433 /* i'th block in an MCU */
435 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
438 * Links to compression subobjects (methods and private variables of modules)
440 struct jpeg_comp_master * master;
441 struct jpeg_c_main_controller * main;
442 struct jpeg_c_prep_controller * prep;
443 struct jpeg_c_coef_controller * coef;
444 struct jpeg_marker_writer * marker;
445 struct jpeg_color_converter * cconvert;
446 struct jpeg_downsampler * downsample;
447 struct jpeg_forward_dct * fdct;
448 struct jpeg_entropy_encoder * entropy;
452 /* Master record for a decompression instance */
454 struct jpeg_decompress_struct {
455 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
457 /* Source of compressed data */
458 struct jpeg_source_mgr * src;
460 /* Basic description of image --- filled in by jpeg_read_header(). */
461 /* Application may inspect these values to decide how to process image. */
463 JDIMENSION image_width; /* nominal image width (from SOF marker) */
464 JDIMENSION image_height; /* nominal image height */
465 int num_components; /* # of color components in JPEG image */
466 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
468 /* Decompression processing parameters --- these fields must be set before
469 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
470 * them to default values.
473 J_COLOR_SPACE out_color_space; /* colorspace for output */
475 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
477 double output_gamma; /* image gamma wanted in output */
479 boolean buffered_image; /* TRUE=multiple output passes */
480 boolean raw_data_out; /* TRUE=downsampled data wanted */
482 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
483 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
484 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
486 boolean quantize_colors; /* TRUE=colormapped output wanted */
487 /* the following are ignored if not quantize_colors: */
488 J_DITHER_MODE dither_mode; /* type of color dithering to use */
489 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
490 int desired_number_of_colors; /* max # colors to use in created colormap */
491 /* these are significant only in buffered-image mode: */
492 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
493 boolean enable_external_quant;/* enable future use of external colormap */
494 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
496 /* Description of actual output image that will be returned to application.
497 * These fields are computed by jpeg_start_decompress().
498 * You can also use jpeg_calc_output_dimensions() to determine these values
499 * in advance of calling jpeg_start_decompress().
502 JDIMENSION output_width; /* scaled image width */
503 JDIMENSION output_height; /* scaled image height */
504 int out_color_components; /* # of color components in out_color_space */
505 int output_components; /* # of color components returned */
506 /* output_components is 1 (a colormap index) when quantizing colors;
507 * otherwise it equals out_color_components.
509 int rec_outbuf_height; /* min recommended height of scanline buffer */
510 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
511 * high, space and time will be wasted due to unnecessary data copying.
512 * Usually rec_outbuf_height will be 1 or 2, at most 4.
515 /* When quantizing colors, the output colormap is described by these fields.
516 * The application can supply a colormap by setting colormap non-NULL before
517 * calling jpeg_start_decompress; otherwise a colormap is created during
518 * jpeg_start_decompress or jpeg_start_output.
519 * The map has out_color_components rows and actual_number_of_colors columns.
521 int actual_number_of_colors; /* number of entries in use */
522 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
524 /* State variables: these variables indicate the progress of decompression.
525 * The application may examine these but must not modify them.
528 /* Row index of next scanline to be read from jpeg_read_scanlines().
529 * Application may use this to control its processing loop, e.g.,
530 * "while (output_scanline < output_height)".
532 JDIMENSION output_scanline; /* 0 .. output_height-1 */
534 /* Current input scan number and number of iMCU rows completed in scan.
535 * These indicate the progress of the decompressor input side.
537 int input_scan_number; /* Number of SOS markers seen so far */
538 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
540 /* The "output scan number" is the notional scan being displayed by the
541 * output side. The decompressor will not allow output scan/row number
542 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
544 int output_scan_number; /* Nominal scan number being displayed */
545 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
547 /* Current progression status. coef_bits[c][i] indicates the precision
548 * with which component c's DCT coefficient i (in zigzag order) is known.
549 * It is -1 when no data has yet been received, otherwise it is the point
550 * transform (shift) value for the most recent scan of the coefficient
551 * (thus, 0 at completion of the progression).
552 * This pointer is NULL when reading a non-progressive file.
554 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
556 /* Internal JPEG parameters --- the application usually need not look at
557 * these fields. Note that the decompressor output side may not use
558 * any parameters that can change between scans.
561 /* Quantization and Huffman tables are carried forward across input
562 * datastreams when processing abbreviated JPEG datastreams.
565 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
566 /* ptrs to coefficient quantization tables, or NULL if not defined */
568 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
569 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
570 /* ptrs to Huffman coding tables, or NULL if not defined */
572 /* These parameters are never carried across datastreams, since they
573 * are given in SOF/SOS markers or defined to be reset by SOI.
576 int data_precision; /* bits of precision in image data */
578 jpeg_component_info * comp_info;
579 /* comp_info[i] describes component that appears i'th in SOF */
581 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
582 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
584 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
585 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
586 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
588 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
590 /* These fields record data obtained from optional markers recognized by
593 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
594 /* Data copied from JFIF marker: */
595 UINT8 density_unit; /* JFIF code for pixel size units */
596 UINT16 X_density; /* Horizontal pixel density */
597 UINT16 Y_density; /* Vertical pixel density */
598 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
599 UINT8 Adobe_transform; /* Color transform code from Adobe marker */
601 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
603 /* Remaining fields are known throughout decompressor, but generally
604 * should not be touched by a surrounding application.
608 * These fields are computed during decompression startup
610 int max_h_samp_factor; /* largest h_samp_factor */
611 int max_v_samp_factor; /* largest v_samp_factor */
613 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */
615 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
616 /* The coefficient controller's input and output progress is measured in
617 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
618 * in fully interleaved JPEG scans, but are used whether the scan is
619 * interleaved or not. We define an iMCU row as v_samp_factor DCT block
620 * rows of each component. Therefore, the IDCT output contains
621 * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
624 JSAMPLE * sample_range_limit; /* table for fast range-limiting */
627 * These fields are valid during any one scan.
628 * They describe the components and MCUs actually appearing in the scan.
629 * Note that the decompressor output side must not use these fields.
631 int comps_in_scan; /* # of JPEG components in this scan */
632 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
633 /* *cur_comp_info[i] describes component that appears i'th in SOS */
635 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
636 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
638 int blocks_in_MCU; /* # of DCT blocks per MCU */
639 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
640 /* MCU_membership[i] is index in cur_comp_info of component owning */
641 /* i'th block in an MCU */
643 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
645 /* This field is shared between entropy decoder and marker parser.
646 * It is either zero or the code of a JPEG marker that has been
647 * read from the data source, but has not yet been processed.
652 * Links to decompression subobjects (methods, private variables of modules)
654 struct jpeg_decomp_master * master;
655 struct jpeg_d_main_controller * main;
656 struct jpeg_d_coef_controller * coef;
657 struct jpeg_d_post_controller * post;
658 struct jpeg_input_controller * inputctl;
659 struct jpeg_marker_reader * marker;
660 struct jpeg_entropy_decoder * entropy;
661 struct jpeg_inverse_dct * idct;
662 struct jpeg_upsampler * upsample;
663 struct jpeg_color_deconverter * cconvert;
664 struct jpeg_color_quantizer * cquantize;
668 /* "Object" declarations for JPEG modules that may be supplied or called
669 * directly by the surrounding application.
670 * As with all objects in the JPEG library, these structs only define the
671 * publicly visible methods and state variables of a module. Additional
672 * private fields may exist after the public ones.
676 /* Error handler object */
678 struct jpeg_error_mgr {
679 /* Error exit handler: does not return to caller */
680 JMETHOD(void, error_exit, (j_common_ptr cinfo));
681 /* Conditionally emit a trace or warning message */
682 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
683 /* Routine that actually outputs a trace or error message */
684 JMETHOD(void, output_message, (j_common_ptr cinfo));
685 /* Format a message string for the most recent JPEG error or message */
686 JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
687 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
688 /* Reset error state variables at start of a new image */
689 JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
691 /* The message ID code and any parameters are saved here.
692 * A message can have one string parameter or up to 8 int parameters.
695 #define JMSG_STR_PARM_MAX 80
698 char s[JMSG_STR_PARM_MAX];
701 /* Standard state variables for error facility */
703 int trace_level; /* max msg_level that will be displayed */
705 /* For recoverable corrupt-data errors, we emit a warning message,
706 * but keep going unless emit_message chooses to abort. emit_message
707 * should count warnings in num_warnings. The surrounding application
708 * can check for bad data by seeing if num_warnings is nonzero at the
711 long num_warnings; /* number of corrupt-data warnings */
713 /* These fields point to the table(s) of error message strings.
714 * An application can change the table pointer to switch to a different
715 * message list (typically, to change the language in which errors are
716 * reported). Some applications may wish to add additional error codes
717 * that will be handled by the JPEG library error mechanism; the second
718 * table pointer is used for this purpose.
720 * First table includes all errors generated by JPEG library itself.
721 * Error code 0 is reserved for a "no such error string" message.
723 const char * const * jpeg_message_table; /* Library errors */
724 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
725 /* Second table can be added by application (see cjpeg/djpeg for example).
726 * It contains strings numbered first_addon_message..last_addon_message.
728 const char * const * addon_message_table; /* Non-library errors */
729 int first_addon_message; /* code for first string in addon table */
730 int last_addon_message; /* code for last string in addon table */
734 /* Progress monitor object */
736 struct jpeg_progress_mgr {
737 JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
739 long pass_counter; /* work units completed in this pass */
740 long pass_limit; /* total number of work units in this pass */
741 int completed_passes; /* passes completed so far */
742 int total_passes; /* total number of passes expected */
746 /* Data destination object for compression */
748 struct jpeg_destination_mgr {
749 JOCTET * next_output_byte; /* => next byte to write in buffer */
750 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
752 JMETHOD(void, init_destination, (j_compress_ptr cinfo));
753 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
754 JMETHOD(void, term_destination, (j_compress_ptr cinfo));
758 /* Data source object for decompression */
760 struct jpeg_source_mgr {
761 const JOCTET * next_input_byte; /* => next byte to read from buffer */
762 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
764 JMETHOD(void, init_source, (j_decompress_ptr cinfo));
765 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
766 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
767 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
768 JMETHOD(void, term_source, (j_decompress_ptr cinfo));
772 /* Memory manager object.
773 * Allocates "small" objects (a few K total), "large" objects (tens of K),
774 * and "really big" objects (virtual arrays with backing store if needed).
775 * The memory manager does not allow individual objects to be freed; rather,
776 * each created object is assigned to a pool, and whole pools can be freed
777 * at once. This is faster and more convenient than remembering exactly what
778 * to free, especially where malloc()/free() are not too speedy.
779 * NB: alloc routines never return NULL. They exit to error_exit if not
783 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
784 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
785 #define JPOOL_NUMPOOLS 2
787 typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
788 typedef struct jvirt_barray_control * jvirt_barray_ptr;
791 struct jpeg_memory_mgr {
792 /* Method pointers */
793 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
794 size_t sizeofobject));
795 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
796 size_t sizeofobject));
797 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
798 JDIMENSION samplesperrow,
799 JDIMENSION numrows));
800 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
801 JDIMENSION blocksperrow,
802 JDIMENSION numrows));
803 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
806 JDIMENSION samplesperrow,
808 JDIMENSION maxaccess));
809 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
812 JDIMENSION blocksperrow,
814 JDIMENSION maxaccess));
815 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
816 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
817 jvirt_sarray_ptr ptr,
818 JDIMENSION start_row,
821 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
822 jvirt_barray_ptr ptr,
823 JDIMENSION start_row,
826 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
827 JMETHOD(void, self_destruct, (j_common_ptr cinfo));
829 /* Limit on memory allocation for this JPEG object. (Note that this is
830 * merely advisory, not a guaranteed maximum; it only affects the space
831 * used for virtual-array buffers.) May be changed by outer application
832 * after creating the JPEG object.
834 long max_memory_to_use;
838 /* Routine signature for application-supplied marker processing methods.
839 * Need not pass marker code since it is stored in cinfo->unread_marker.
841 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
844 /* Declarations for routines called by application.
845 * The JPP macro hides prototype parameters from compilers that can't cope.
846 * Note JPP requires double parentheses.
849 #ifdef HAVE_PROTOTYPES
850 #define JPP(arglist) arglist
852 #define JPP(arglist) ()
856 /* Short forms of external names for systems with brain-damaged linkers.
857 * We shorten external names to be unique in the first six letters, which
858 * is good enough for all known systems.
859 * (If your compiler itself needs names to be unique in less than 15
860 * characters, you are out of luck. Get a better compiler.)
863 #ifdef NEED_SHORT_EXTERNAL_NAMES
864 #define jpeg_std_error jStdError
865 #define jpeg_create_compress jCreaCompress
866 #define jpeg_create_decompress jCreaDecompress
867 #define jpeg_destroy_compress jDestCompress
868 #define jpeg_destroy_decompress jDestDecompress
869 #define jpeg_stdio_dest jStdDest
870 #define jpeg_stdio_src jStdSrc
871 #define jpeg_set_defaults jSetDefaults
872 #define jpeg_set_colorspace jSetColorspace
873 #define jpeg_default_colorspace jDefColorspace
874 #define jpeg_set_quality jSetQuality
875 #define jpeg_set_linear_quality jSetLQuality
876 #define jpeg_add_quant_table jAddQuantTable
877 #define jpeg_quality_scaling jQualityScaling
878 #define jpeg_simple_progression jSimProgress
879 #define jpeg_suppress_tables jSuppressTables
880 #define jpeg_alloc_quant_table jAlcQTable
881 #define jpeg_alloc_huff_table jAlcHTable
882 #define jpeg_start_compress jStrtCompress
883 #define jpeg_write_scanlines jWrtScanlines
884 #define jpeg_finish_compress jFinCompress
885 #define jpeg_write_raw_data jWrtRawData
886 #define jpeg_write_marker jWrtMarker
887 #define jpeg_write_tables jWrtTables
888 #define jpeg_read_header jReadHeader
889 #define jpeg_start_decompress jStrtDecompress
890 #define jpeg_read_scanlines jReadScanlines
891 #define jpeg_finish_decompress jFinDecompress
892 #define jpeg_read_raw_data jReadRawData
893 #define jpeg_has_multiple_scans jHasMultScn
894 #define jpeg_start_output jStrtOutput
895 #define jpeg_finish_output jFinOutput
896 #define jpeg_input_complete jInComplete
897 #define jpeg_new_colormap jNewCMap
898 #define jpeg_consume_input jConsumeInput
899 #define jpeg_calc_output_dimensions jCalcDimensions
900 #define jpeg_set_marker_processor jSetMarker
901 #define jpeg_read_coefficients jReadCoefs
902 #define jpeg_write_coefficients jWrtCoefs
903 #define jpeg_copy_critical_parameters jCopyCrit
904 #define jpeg_abort_compress jAbrtCompress
905 #define jpeg_abort_decompress jAbrtDecompress
906 #define jpeg_abort jAbort
907 #define jpeg_destroy jDestroy
908 #define jpeg_resync_to_restart jResyncRestart
909 #endif /* NEED_SHORT_EXTERNAL_NAMES */
912 /* Default error-management setup */
913 EXTERN struct jpeg_error_mgr *jpeg_std_error JPP((struct jpeg_error_mgr *err));
915 /* Initialization and destruction of JPEG compression objects */
916 /* NB: you must set up the error-manager BEFORE calling jpeg_create_xxx */
917 EXTERN void jpeg_create_compress JPP((j_compress_ptr cinfo));
918 EXTERN void jpeg_create_decompress JPP((j_decompress_ptr cinfo));
919 EXTERN void jpeg_destroy_compress JPP((j_compress_ptr cinfo));
920 EXTERN void jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
922 /* Standard data source and destination managers: stdio streams. */
923 /* Caller is responsible for opening the file before and closing after. */
924 EXTERN void jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
925 EXTERN void jpeg_stdio_src JPP((j_decompress_ptr cinfo, unsigned char *infile, int bufsize));
927 /* Default parameter setup for compression */
928 EXTERN void jpeg_set_defaults JPP((j_compress_ptr cinfo));
929 /* Compression parameter setup aids */
930 EXTERN void jpeg_set_colorspace JPP((j_compress_ptr cinfo,
931 J_COLOR_SPACE colorspace));
932 EXTERN void jpeg_default_colorspace JPP((j_compress_ptr cinfo));
933 EXTERN void jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
934 boolean force_baseline));
935 EXTERN void jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
937 boolean force_baseline));
938 EXTERN void jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
939 const unsigned int *basic_table,
941 boolean force_baseline));
942 EXTERN int jpeg_quality_scaling JPP((int quality));
943 EXTERN void jpeg_simple_progression JPP((j_compress_ptr cinfo));
944 EXTERN void jpeg_suppress_tables JPP((j_compress_ptr cinfo,
946 EXTERN JQUANT_TBL * jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
947 EXTERN JHUFF_TBL * jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
949 /* Main entry points for compression */
950 EXTERN void jpeg_start_compress JPP((j_compress_ptr cinfo,
951 boolean write_all_tables));
952 EXTERN JDIMENSION jpeg_write_scanlines JPP((j_compress_ptr cinfo,
953 JSAMPARRAY scanlines,
954 JDIMENSION num_lines));
955 EXTERN void jpeg_finish_compress JPP((j_compress_ptr cinfo));
957 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
958 EXTERN JDIMENSION jpeg_write_raw_data JPP((j_compress_ptr cinfo,
960 JDIMENSION num_lines));
962 /* Write a special marker. See libjpeg.doc concerning safe usage. */
963 EXTERN void jpeg_write_marker JPP((j_compress_ptr cinfo, int marker,
964 const JOCTET *dataptr, unsigned int datalen));
966 /* Alternate compression function: just write an abbreviated table file */
967 EXTERN void jpeg_write_tables JPP((j_compress_ptr cinfo));
969 /* Decompression startup: read start of JPEG datastream to see what's there */
970 EXTERN int jpeg_read_header JPP((j_decompress_ptr cinfo,
971 boolean require_image));
972 /* Return value is one of: */
973 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
974 #define JPEG_HEADER_OK 1 /* Found valid image datastream */
975 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
976 /* If you pass require_image = TRUE (normal case), you need not check for
977 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
978 * JPEG_SUSPENDED is only possible if you use a data source module that can
979 * give a suspension return (the stdio source module doesn't).
982 /* Main entry points for decompression */
983 EXTERN boolean jpeg_start_decompress JPP((j_decompress_ptr cinfo));
984 EXTERN JDIMENSION jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
985 JSAMPARRAY scanlines,
986 JDIMENSION max_lines));
987 EXTERN boolean jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
989 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
990 EXTERN JDIMENSION jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
992 JDIMENSION max_lines));
994 /* Additional entry points for buffered-image mode. */
995 EXTERN boolean jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
996 EXTERN boolean jpeg_start_output JPP((j_decompress_ptr cinfo,
998 EXTERN boolean jpeg_finish_output JPP((j_decompress_ptr cinfo));
999 EXTERN boolean jpeg_input_complete JPP((j_decompress_ptr cinfo));
1000 EXTERN void jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1001 EXTERN int jpeg_consume_input JPP((j_decompress_ptr cinfo));
1002 /* Return value is one of: */
1003 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1004 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1005 #define JPEG_REACHED_EOI 2 /* Reached end of image */
1006 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1007 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1009 /* Precalculate output dimensions for current decompression parameters. */
1010 EXTERN void jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1012 /* Install a special processing method for COM or APPn markers. */
1013 EXTERN void jpeg_set_marker_processor JPP((j_decompress_ptr cinfo,
1015 jpeg_marker_parser_method routine));
1017 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1018 EXTERN jvirt_barray_ptr * jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1019 EXTERN void jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1020 jvirt_barray_ptr * coef_arrays));
1021 EXTERN void jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1022 j_compress_ptr dstinfo));
1024 /* If you choose to abort compression or decompression before completing
1025 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1026 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1027 * if you're done with the JPEG object, but if you want to clean it up and
1028 * reuse it, call this:
1030 EXTERN void jpeg_abort_compress JPP((j_compress_ptr cinfo));
1031 EXTERN void jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1033 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1034 * flavor of JPEG object. These may be more convenient in some places.
1036 EXTERN void jpeg_abort JPP((j_common_ptr cinfo));
1037 EXTERN void jpeg_destroy JPP((j_common_ptr cinfo));
1039 /* Default restart-marker-resync procedure for use by data source modules */
1040 EXTERN boolean jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1044 /* These marker codes are exported since applications and data source modules
1045 * are likely to want to use them.
1048 #define JPEG_RST0 0xD0 /* RST0 marker code */
1049 #define JPEG_EOI 0xD9 /* EOI marker code */
1050 #define JPEG_APP0 0xE0 /* APP0 marker code */
1051 #define JPEG_COM 0xFE /* COM marker code */
1054 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1055 * for structure definitions that are never filled in, keep it quiet by
1056 * supplying dummy definitions for the various substructures.
1059 #ifdef INCOMPLETE_TYPES_BROKEN
1060 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1061 struct jvirt_sarray_control { long dummy; };
1062 struct jvirt_barray_control { long dummy; };
1063 struct jpeg_comp_master { long dummy; };
1064 struct jpeg_c_main_controller { long dummy; };
1065 struct jpeg_c_prep_controller { long dummy; };
1066 struct jpeg_c_coef_controller { long dummy; };
1067 struct jpeg_marker_writer { long dummy; };
1068 struct jpeg_color_converter { long dummy; };
1069 struct jpeg_downsampler { long dummy; };
1070 struct jpeg_forward_dct { long dummy; };
1071 struct jpeg_entropy_encoder { long dummy; };
1072 struct jpeg_decomp_master { long dummy; };
1073 struct jpeg_d_main_controller { long dummy; };
1074 struct jpeg_d_coef_controller { long dummy; };
1075 struct jpeg_d_post_controller { long dummy; };
1076 struct jpeg_input_controller { long dummy; };
1077 struct jpeg_marker_reader { long dummy; };
1078 struct jpeg_entropy_decoder { long dummy; };
1079 struct jpeg_inverse_dct { long dummy; };
1080 struct jpeg_upsampler { long dummy; };
1081 struct jpeg_color_deconverter { long dummy; };
1082 struct jpeg_color_quantizer { long dummy; };
1083 #endif /* JPEG_INTERNALS */
1084 #endif /* INCOMPLETE_TYPES_BROKEN */
1088 * The JPEG library modules define JPEG_INTERNALS before including this file.
1089 * The internal structure declarations are read only when that is true.
1090 * Applications using the library should not include jpegint.h, but may wish
1091 * to include jerror.h.
1094 #ifdef JPEG_INTERNALS
1095 #include "jpegint.h" /* fetch private declarations */
1096 #include "jerror.h" /* fetch error codes too */
1103 #endif /* JPEGLIB_H */