2 * CDE - Common Desktop Environment
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6 * These libraries and programs are free software; you can
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15 * PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public
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23 /* $XConsortium: jpeglib.h /main/2 1996/05/09 03:53:41 drk $ */
27 * Copyright (C) 1991-1996, Thomas G. Lane.
28 * This file is part of the Independent JPEG Group's software.
29 * For conditions of distribution and use, see the accompanying README file.
31 * This file defines the application interface for the JPEG library.
32 * Most applications using the library need only include this file,
33 * and perhaps jerror.h if they want to know the exact error codes.
40 * First we include the configuration files that record how this
41 * installation of the JPEG library is set up. jconfig.h can be
42 * generated automatically for many systems. jmorecfg.h contains
43 * manual configuration options that most people need not worry about.
46 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
47 #include "jconfig.h" /* widely used configuration options */
49 #include "jmorecfg.h" /* seldom changed options */
52 /* Version ID for the JPEG library.
53 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
56 #define JPEG_LIB_VERSION 61 /* Version 6a */
59 /* Various constants determining the sizes of things.
60 * All of these are specified by the JPEG standard, so don't change them
61 * if you want to be compatible.
64 #define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
65 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
66 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
67 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
68 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
69 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
70 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
71 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
72 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
73 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
74 * to handle it. We even let you do this from the jconfig.h file. However,
75 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
76 * sometimes emits noncompliant files doesn't mean you should too.
78 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
79 #ifndef D_MAX_BLOCKS_IN_MCU
80 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
84 /* Data structures for images (arrays of samples and of DCT coefficients).
85 * On 80x86 machines, the image arrays are too big for near pointers,
86 * but the pointer arrays can fit in near memory.
89 typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
90 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
91 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
93 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
94 typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
95 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
96 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
98 typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
101 /* Types for JPEG compression parameters and working tables. */
104 /* DCT coefficient quantization tables. */
107 /* This array gives the coefficient quantizers in natural array order
108 * (not the zigzag order in which they are stored in a JPEG DQT marker).
109 * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
111 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
112 /* This field is used only during compression. It's initialized FALSE when
113 * the table is created, and set TRUE when it's been output to the file.
114 * You could suppress output of a table by setting this to TRUE.
115 * (See jpeg_suppress_tables for an example.)
117 boolean sent_table; /* TRUE when table has been output */
121 /* Huffman coding tables. */
124 /* These two fields directly represent the contents of a JPEG DHT marker */
125 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
126 /* length k bits; bits[0] is unused */
127 UINT8 huffval[256]; /* The symbols, in order of incr code length */
128 /* This field is used only during compression. It's initialized FALSE when
129 * the table is created, and set TRUE when it's been output to the file.
130 * You could suppress output of a table by setting this to TRUE.
131 * (See jpeg_suppress_tables for an example.)
133 boolean sent_table; /* TRUE when table has been output */
137 /* Basic info about one component (color channel). */
140 /* These values are fixed over the whole image. */
141 /* For compression, they must be supplied by parameter setup; */
142 /* for decompression, they are read from the SOF marker. */
143 int component_id; /* identifier for this component (0..255) */
144 int component_index; /* its index in SOF or cinfo->comp_info[] */
145 int h_samp_factor; /* horizontal sampling factor (1..4) */
146 int v_samp_factor; /* vertical sampling factor (1..4) */
147 int quant_tbl_no; /* quantization table selector (0..3) */
148 /* These values may vary between scans. */
149 /* For compression, they must be supplied by parameter setup; */
150 /* for decompression, they are read from the SOS marker. */
151 /* The decompressor output side may not use these variables. */
152 int dc_tbl_no; /* DC entropy table selector (0..3) */
153 int ac_tbl_no; /* AC entropy table selector (0..3) */
155 /* Remaining fields should be treated as private by applications. */
157 /* These values are computed during compression or decompression startup: */
158 /* Component's size in DCT blocks.
159 * Any dummy blocks added to complete an MCU are not counted; therefore
160 * these values do not depend on whether a scan is interleaved or not.
162 JDIMENSION width_in_blocks;
163 JDIMENSION height_in_blocks;
164 /* Size of a DCT block in samples. Always DCTSIZE for compression.
165 * For decompression this is the size of the output from one DCT block,
166 * reflecting any scaling we choose to apply during the IDCT step.
167 * Values of 1,2,4,8 are likely to be supported. Note that different
168 * components may receive different IDCT scalings.
171 /* The downsampled dimensions are the component's actual, unpadded number
172 * of samples at the main buffer (preprocessing/compression interface), thus
173 * downsampled_width = ceil(image_width * Hi/Hmax)
174 * and similarly for height. For decompression, IDCT scaling is included, so
175 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)
177 JDIMENSION downsampled_width; /* actual width in samples */
178 JDIMENSION downsampled_height; /* actual height in samples */
179 /* This flag is used only for decompression. In cases where some of the
180 * components will be ignored (eg grayscale output from YCbCr image),
181 * we can skip most computations for the unused components.
183 boolean component_needed; /* do we need the value of this component? */
185 /* These values are computed before starting a scan of the component. */
186 /* The decompressor output side may not use these variables. */
187 int MCU_width; /* number of blocks per MCU, horizontally */
188 int MCU_height; /* number of blocks per MCU, vertically */
189 int MCU_blocks; /* MCU_width * MCU_height */
190 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_scaled_size */
191 int last_col_width; /* # of non-dummy blocks across in last MCU */
192 int last_row_height; /* # of non-dummy blocks down in last MCU */
194 /* Saved quantization table for component; NULL if none yet saved.
195 * See jdinput.c comments about the need for this information.
196 * This field is currently used only for decompression.
198 JQUANT_TBL * quant_table;
200 /* Private per-component storage for DCT or IDCT subsystem. */
202 } jpeg_component_info;
205 /* The script for encoding a multiple-scan file is an array of these: */
208 int comps_in_scan; /* number of components encoded in this scan */
209 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
210 int Ss, Se; /* progressive JPEG spectral selection parms */
211 int Ah, Al; /* progressive JPEG successive approx. parms */
215 /* Known color spaces. */
218 JCS_UNKNOWN, /* error/unspecified */
219 JCS_GRAYSCALE, /* monochrome */
220 JCS_RGB, /* red/green/blue */
221 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
222 JCS_CMYK, /* C/M/Y/K */
223 JCS_YCCK /* Y/Cb/Cr/K */
226 /* DCT/IDCT algorithm options. */
229 JDCT_ISLOW, /* slow but accurate integer algorithm */
230 JDCT_IFAST, /* faster, less accurate integer method */
231 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
234 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
235 #define JDCT_DEFAULT JDCT_ISLOW
237 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
238 #define JDCT_FASTEST JDCT_IFAST
241 /* Dithering options for decompression. */
244 JDITHER_NONE, /* no dithering */
245 JDITHER_ORDERED, /* simple ordered dither */
246 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
250 /* Common fields between JPEG compression and decompression master structs. */
252 #define jpeg_common_fields \
253 struct jpeg_error_mgr * err; /* Error handler module */\
254 struct jpeg_memory_mgr * mem; /* Memory manager module */\
255 struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
256 boolean is_decompressor; /* so common code can tell which is which */\
257 int global_state /* for checking call sequence validity */
259 /* Routines that are to be used by both halves of the library are declared
260 * to receive a pointer to this structure. There are no actual instances of
261 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
263 struct jpeg_common_struct {
264 jpeg_common_fields; /* Fields common to both master struct types */
265 /* Additional fields follow in an actual jpeg_compress_struct or
266 * jpeg_decompress_struct. All three structs must agree on these
267 * initial fields! (This would be a lot cleaner in C++.)
271 typedef struct jpeg_common_struct * j_common_ptr;
272 typedef struct jpeg_compress_struct * j_compress_ptr;
273 typedef struct jpeg_decompress_struct * j_decompress_ptr;
276 /* Master record for a compression instance */
278 struct jpeg_compress_struct {
279 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
281 /* Destination for compressed data */
282 struct jpeg_destination_mgr * dest;
284 /* Description of source image --- these fields must be filled in by
285 * outer application before starting compression. in_color_space must
286 * be correct before you can even call jpeg_set_defaults().
289 JDIMENSION image_width; /* input image width */
290 JDIMENSION image_height; /* input image height */
291 int input_components; /* # of color components in input image */
292 J_COLOR_SPACE in_color_space; /* colorspace of input image */
294 double input_gamma; /* image gamma of input image */
296 /* Compression parameters --- these fields must be set before calling
297 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
298 * initialize everything to reasonable defaults, then changing anything
299 * the application specifically wants to change. That way you won't get
300 * burnt when new parameters are added. Also note that there are several
301 * helper routines to simplify changing parameters.
304 int data_precision; /* bits of precision in image data */
306 int num_components; /* # of color components in JPEG image */
307 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
309 jpeg_component_info * comp_info;
310 /* comp_info[i] describes component that appears i'th in SOF */
312 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
313 /* ptrs to coefficient quantization tables, or NULL if not defined */
315 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
316 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
317 /* ptrs to Huffman coding tables, or NULL if not defined */
319 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
320 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
321 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
323 int num_scans; /* # of entries in scan_info array */
324 const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
325 /* The default value of scan_info is NULL, which causes a single-scan
326 * sequential JPEG file to be emitted. To create a multi-scan file,
327 * set num_scans and scan_info to point to an array of scan definitions.
330 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
331 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
332 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
333 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
334 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
335 J_DCT_METHOD dct_method; /* DCT algorithm selector */
337 /* The restart interval can be specified in absolute MCUs by setting
338 * restart_interval, or in MCU rows by setting restart_in_rows
339 * (in which case the correct restart_interval will be figured
342 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
343 int restart_in_rows; /* if > 0, MCU rows per restart interval */
345 /* Parameters controlling emission of special markers. */
347 boolean write_JFIF_header; /* should a JFIF marker be written? */
348 /* These three values are not used by the JPEG code, merely copied */
349 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
350 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
351 /* ratio is defined by X_density/Y_density even when density_unit=0. */
352 UINT8 density_unit; /* JFIF code for pixel size units */
353 UINT16 X_density; /* Horizontal pixel density */
354 UINT16 Y_density; /* Vertical pixel density */
355 boolean write_Adobe_marker; /* should an Adobe marker be written? */
357 /* State variable: index of next scanline to be written to
358 * jpeg_write_scanlines(). Application may use this to control its
359 * processing loop, e.g., "while (next_scanline < image_height)".
362 JDIMENSION next_scanline; /* 0 .. image_height-1 */
364 /* Remaining fields are known throughout compressor, but generally
365 * should not be touched by a surrounding application.
369 * These fields are computed during compression startup
371 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
372 int max_h_samp_factor; /* largest h_samp_factor */
373 int max_v_samp_factor; /* largest v_samp_factor */
375 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
376 /* The coefficient controller receives data in units of MCU rows as defined
377 * for fully interleaved scans (whether the JPEG file is interleaved or not).
378 * There are v_samp_factor * DCTSIZE sample rows of each component in an
379 * "iMCU" (interleaved MCU) row.
383 * These fields are valid during any one scan.
384 * They describe the components and MCUs actually appearing in the scan.
386 int comps_in_scan; /* # of JPEG components in this scan */
387 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
388 /* *cur_comp_info[i] describes component that appears i'th in SOS */
390 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
391 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
393 int blocks_in_MCU; /* # of DCT blocks per MCU */
394 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
395 /* MCU_membership[i] is index in cur_comp_info of component owning */
396 /* i'th block in an MCU */
398 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
401 * Links to compression subobjects (methods and private variables of modules)
403 struct jpeg_comp_master * master;
404 struct jpeg_c_main_controller * main;
405 struct jpeg_c_prep_controller * prep;
406 struct jpeg_c_coef_controller * coef;
407 struct jpeg_marker_writer * marker;
408 struct jpeg_color_converter * cconvert;
409 struct jpeg_downsampler * downsample;
410 struct jpeg_forward_dct * fdct;
411 struct jpeg_entropy_encoder * entropy;
415 /* Master record for a decompression instance */
417 struct jpeg_decompress_struct {
418 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
420 /* Source of compressed data */
421 struct jpeg_source_mgr * src;
423 /* Basic description of image --- filled in by jpeg_read_header(). */
424 /* Application may inspect these values to decide how to process image. */
426 JDIMENSION image_width; /* nominal image width (from SOF marker) */
427 JDIMENSION image_height; /* nominal image height */
428 int num_components; /* # of color components in JPEG image */
429 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
431 /* Decompression processing parameters --- these fields must be set before
432 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
433 * them to default values.
436 J_COLOR_SPACE out_color_space; /* colorspace for output */
438 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
440 double output_gamma; /* image gamma wanted in output */
442 boolean buffered_image; /* TRUE=multiple output passes */
443 boolean raw_data_out; /* TRUE=downsampled data wanted */
445 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
446 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
447 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
449 boolean quantize_colors; /* TRUE=colormapped output wanted */
450 /* the following are ignored if not quantize_colors: */
451 J_DITHER_MODE dither_mode; /* type of color dithering to use */
452 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
453 int desired_number_of_colors; /* max # colors to use in created colormap */
454 /* these are significant only in buffered-image mode: */
455 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
456 boolean enable_external_quant;/* enable future use of external colormap */
457 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
459 /* Description of actual output image that will be returned to application.
460 * These fields are computed by jpeg_start_decompress().
461 * You can also use jpeg_calc_output_dimensions() to determine these values
462 * in advance of calling jpeg_start_decompress().
465 JDIMENSION output_width; /* scaled image width */
466 JDIMENSION output_height; /* scaled image height */
467 int out_color_components; /* # of color components in out_color_space */
468 int output_components; /* # of color components returned */
469 /* output_components is 1 (a colormap index) when quantizing colors;
470 * otherwise it equals out_color_components.
472 int rec_outbuf_height; /* min recommended height of scanline buffer */
473 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
474 * high, space and time will be wasted due to unnecessary data copying.
475 * Usually rec_outbuf_height will be 1 or 2, at most 4.
478 /* When quantizing colors, the output colormap is described by these fields.
479 * The application can supply a colormap by setting colormap non-NULL before
480 * calling jpeg_start_decompress; otherwise a colormap is created during
481 * jpeg_start_decompress or jpeg_start_output.
482 * The map has out_color_components rows and actual_number_of_colors columns.
484 int actual_number_of_colors; /* number of entries in use */
485 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
487 /* State variables: these variables indicate the progress of decompression.
488 * The application may examine these but must not modify them.
491 /* Row index of next scanline to be read from jpeg_read_scanlines().
492 * Application may use this to control its processing loop, e.g.,
493 * "while (output_scanline < output_height)".
495 JDIMENSION output_scanline; /* 0 .. output_height-1 */
497 /* Current input scan number and number of iMCU rows completed in scan.
498 * These indicate the progress of the decompressor input side.
500 int input_scan_number; /* Number of SOS markers seen so far */
501 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
503 /* The "output scan number" is the notional scan being displayed by the
504 * output side. The decompressor will not allow output scan/row number
505 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
507 int output_scan_number; /* Nominal scan number being displayed */
508 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
510 /* Current progression status. coef_bits[c][i] indicates the precision
511 * with which component c's DCT coefficient i (in zigzag order) is known.
512 * It is -1 when no data has yet been received, otherwise it is the point
513 * transform (shift) value for the most recent scan of the coefficient
514 * (thus, 0 at completion of the progression).
515 * This pointer is NULL when reading a non-progressive file.
517 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
519 /* Internal JPEG parameters --- the application usually need not look at
520 * these fields. Note that the decompressor output side may not use
521 * any parameters that can change between scans.
524 /* Quantization and Huffman tables are carried forward across input
525 * datastreams when processing abbreviated JPEG datastreams.
528 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
529 /* ptrs to coefficient quantization tables, or NULL if not defined */
531 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
532 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
533 /* ptrs to Huffman coding tables, or NULL if not defined */
535 /* These parameters are never carried across datastreams, since they
536 * are given in SOF/SOS markers or defined to be reset by SOI.
539 int data_precision; /* bits of precision in image data */
541 jpeg_component_info * comp_info;
542 /* comp_info[i] describes component that appears i'th in SOF */
544 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
545 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
547 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
548 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
549 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
551 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
553 /* These fields record data obtained from optional markers recognized by
556 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
557 /* Data copied from JFIF marker: */
558 UINT8 density_unit; /* JFIF code for pixel size units */
559 UINT16 X_density; /* Horizontal pixel density */
560 UINT16 Y_density; /* Vertical pixel density */
561 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
562 UINT8 Adobe_transform; /* Color transform code from Adobe marker */
564 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
566 /* Remaining fields are known throughout decompressor, but generally
567 * should not be touched by a surrounding application.
571 * These fields are computed during decompression startup
573 int max_h_samp_factor; /* largest h_samp_factor */
574 int max_v_samp_factor; /* largest v_samp_factor */
576 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */
578 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
579 /* The coefficient controller's input and output progress is measured in
580 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
581 * in fully interleaved JPEG scans, but are used whether the scan is
582 * interleaved or not. We define an iMCU row as v_samp_factor DCT block
583 * rows of each component. Therefore, the IDCT output contains
584 * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
587 JSAMPLE * sample_range_limit; /* table for fast range-limiting */
590 * These fields are valid during any one scan.
591 * They describe the components and MCUs actually appearing in the scan.
592 * Note that the decompressor output side must not use these fields.
594 int comps_in_scan; /* # of JPEG components in this scan */
595 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
596 /* *cur_comp_info[i] describes component that appears i'th in SOS */
598 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
599 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
601 int blocks_in_MCU; /* # of DCT blocks per MCU */
602 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
603 /* MCU_membership[i] is index in cur_comp_info of component owning */
604 /* i'th block in an MCU */
606 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
608 /* This field is shared between entropy decoder and marker parser.
609 * It is either zero or the code of a JPEG marker that has been
610 * read from the data source, but has not yet been processed.
615 * Links to decompression subobjects (methods, private variables of modules)
617 struct jpeg_decomp_master * master;
618 struct jpeg_d_main_controller * main;
619 struct jpeg_d_coef_controller * coef;
620 struct jpeg_d_post_controller * post;
621 struct jpeg_input_controller * inputctl;
622 struct jpeg_marker_reader * marker;
623 struct jpeg_entropy_decoder * entropy;
624 struct jpeg_inverse_dct * idct;
625 struct jpeg_upsampler * upsample;
626 struct jpeg_color_deconverter * cconvert;
627 struct jpeg_color_quantizer * cquantize;
631 /* "Object" declarations for JPEG modules that may be supplied or called
632 * directly by the surrounding application.
633 * As with all objects in the JPEG library, these structs only define the
634 * publicly visible methods and state variables of a module. Additional
635 * private fields may exist after the public ones.
639 /* Error handler object */
641 struct jpeg_error_mgr {
642 /* Error exit handler: does not return to caller */
643 JMETHOD(void, error_exit, (j_common_ptr cinfo));
644 /* Conditionally emit a trace or warning message */
645 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
646 /* Routine that actually outputs a trace or error message */
647 JMETHOD(void, output_message, (j_common_ptr cinfo));
648 /* Format a message string for the most recent JPEG error or message */
649 JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
650 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
651 /* Reset error state variables at start of a new image */
652 JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
654 /* The message ID code and any parameters are saved here.
655 * A message can have one string parameter or up to 8 int parameters.
658 #define JMSG_STR_PARM_MAX 80
661 char s[JMSG_STR_PARM_MAX];
664 /* Standard state variables for error facility */
666 int trace_level; /* max msg_level that will be displayed */
668 /* For recoverable corrupt-data errors, we emit a warning message,
669 * but keep going unless emit_message chooses to abort. emit_message
670 * should count warnings in num_warnings. The surrounding application
671 * can check for bad data by seeing if num_warnings is nonzero at the
674 long num_warnings; /* number of corrupt-data warnings */
676 /* These fields point to the table(s) of error message strings.
677 * An application can change the table pointer to switch to a different
678 * message list (typically, to change the language in which errors are
679 * reported). Some applications may wish to add additional error codes
680 * that will be handled by the JPEG library error mechanism; the second
681 * table pointer is used for this purpose.
683 * First table includes all errors generated by JPEG library itself.
684 * Error code 0 is reserved for a "no such error string" message.
686 const char * const * jpeg_message_table; /* Library errors */
687 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
688 /* Second table can be added by application (see cjpeg/djpeg for example).
689 * It contains strings numbered first_addon_message..last_addon_message.
691 const char * const * addon_message_table; /* Non-library errors */
692 int first_addon_message; /* code for first string in addon table */
693 int last_addon_message; /* code for last string in addon table */
697 /* Progress monitor object */
699 struct jpeg_progress_mgr {
700 JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
702 long pass_counter; /* work units completed in this pass */
703 long pass_limit; /* total number of work units in this pass */
704 int completed_passes; /* passes completed so far */
705 int total_passes; /* total number of passes expected */
709 /* Data destination object for compression */
711 struct jpeg_destination_mgr {
712 JOCTET * next_output_byte; /* => next byte to write in buffer */
713 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
715 JMETHOD(void, init_destination, (j_compress_ptr cinfo));
716 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
717 JMETHOD(void, term_destination, (j_compress_ptr cinfo));
721 /* Data source object for decompression */
723 struct jpeg_source_mgr {
724 const JOCTET * next_input_byte; /* => next byte to read from buffer */
725 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
727 JMETHOD(void, init_source, (j_decompress_ptr cinfo));
728 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
729 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
730 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
731 JMETHOD(void, term_source, (j_decompress_ptr cinfo));
735 /* Memory manager object.
736 * Allocates "small" objects (a few K total), "large" objects (tens of K),
737 * and "really big" objects (virtual arrays with backing store if needed).
738 * The memory manager does not allow individual objects to be freed; rather,
739 * each created object is assigned to a pool, and whole pools can be freed
740 * at once. This is faster and more convenient than remembering exactly what
741 * to free, especially where malloc()/free() are not too speedy.
742 * NB: alloc routines never return NULL. They exit to error_exit if not
746 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
747 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
748 #define JPOOL_NUMPOOLS 2
750 typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
751 typedef struct jvirt_barray_control * jvirt_barray_ptr;
754 struct jpeg_memory_mgr {
755 /* Method pointers */
756 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
757 size_t sizeofobject));
758 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
759 size_t sizeofobject));
760 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
761 JDIMENSION samplesperrow,
762 JDIMENSION numrows));
763 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
764 JDIMENSION blocksperrow,
765 JDIMENSION numrows));
766 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
769 JDIMENSION samplesperrow,
771 JDIMENSION maxaccess));
772 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
775 JDIMENSION blocksperrow,
777 JDIMENSION maxaccess));
778 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
779 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
780 jvirt_sarray_ptr ptr,
781 JDIMENSION start_row,
784 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
785 jvirt_barray_ptr ptr,
786 JDIMENSION start_row,
789 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
790 JMETHOD(void, self_destruct, (j_common_ptr cinfo));
792 /* Limit on memory allocation for this JPEG object. (Note that this is
793 * merely advisory, not a guaranteed maximum; it only affects the space
794 * used for virtual-array buffers.) May be changed by outer application
795 * after creating the JPEG object.
797 long max_memory_to_use;
801 /* Routine signature for application-supplied marker processing methods.
802 * Need not pass marker code since it is stored in cinfo->unread_marker.
804 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
807 /* Declarations for routines called by application.
808 * The JPP macro hides prototype parameters from compilers that can't cope.
809 * Note JPP requires double parentheses.
812 #ifdef HAVE_PROTOTYPES
813 #define JPP(arglist) arglist
815 #define JPP(arglist) ()
819 /* Short forms of external names for systems with brain-damaged linkers.
820 * We shorten external names to be unique in the first six letters, which
821 * is good enough for all known systems.
822 * (If your compiler itself needs names to be unique in less than 15
823 * characters, you are out of luck. Get a better compiler.)
826 #ifdef NEED_SHORT_EXTERNAL_NAMES
827 #define jpeg_std_error jStdError
828 #define jpeg_CreateCompress jCreaCompress
829 #define jpeg_CreateDecompress jCreaDecompress
830 #define jpeg_destroy_compress jDestCompress
831 #define jpeg_destroy_decompress jDestDecompress
832 #define jpeg_stdio_dest jStdDest
833 #define jpeg_stdio_src jStdSrc
834 #define jpeg_set_defaults jSetDefaults
835 #define jpeg_set_colorspace jSetColorspace
836 #define jpeg_default_colorspace jDefColorspace
837 #define jpeg_set_quality jSetQuality
838 #define jpeg_set_linear_quality jSetLQuality
839 #define jpeg_add_quant_table jAddQuantTable
840 #define jpeg_quality_scaling jQualityScaling
841 #define jpeg_simple_progression jSimProgress
842 #define jpeg_suppress_tables jSuppressTables
843 #define jpeg_alloc_quant_table jAlcQTable
844 #define jpeg_alloc_huff_table jAlcHTable
845 #define jpeg_start_compress jStrtCompress
846 #define jpeg_write_scanlines jWrtScanlines
847 #define jpeg_finish_compress jFinCompress
848 #define jpeg_write_raw_data jWrtRawData
849 #define jpeg_write_marker jWrtMarker
850 #define jpeg_write_tables jWrtTables
851 #define jpeg_read_header jReadHeader
852 #define jpeg_start_decompress jStrtDecompress
853 #define jpeg_read_scanlines jReadScanlines
854 #define jpeg_finish_decompress jFinDecompress
855 #define jpeg_read_raw_data jReadRawData
856 #define jpeg_has_multiple_scans jHasMultScn
857 #define jpeg_start_output jStrtOutput
858 #define jpeg_finish_output jFinOutput
859 #define jpeg_input_complete jInComplete
860 #define jpeg_new_colormap jNewCMap
861 #define jpeg_consume_input jConsumeInput
862 #define jpeg_calc_output_dimensions jCalcDimensions
863 #define jpeg_set_marker_processor jSetMarker
864 #define jpeg_read_coefficients jReadCoefs
865 #define jpeg_write_coefficients jWrtCoefs
866 #define jpeg_copy_critical_parameters jCopyCrit
867 #define jpeg_abort_compress jAbrtCompress
868 #define jpeg_abort_decompress jAbrtDecompress
869 #define jpeg_abort jAbort
870 #define jpeg_destroy jDestroy
871 #define jpeg_resync_to_restart jResyncRestart
872 #endif /* NEED_SHORT_EXTERNAL_NAMES */
875 /* Default error-management setup */
876 EXTERN(struct jpeg_error_mgr *) jpeg_std_error
877 JPP((struct jpeg_error_mgr * err));
879 /* Initialization of JPEG compression objects.
880 * jpeg_create_compress() and jpeg_create_decompress() are the exported
881 * names that applications should call. These expand to calls on
882 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
883 * passed for version mismatch checking.
884 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
886 #define jpeg_create_compress(cinfo) \
887 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
888 (size_t) sizeof(struct jpeg_compress_struct))
889 #define jpeg_create_decompress(cinfo) \
890 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
891 (size_t) sizeof(struct jpeg_decompress_struct))
892 EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
893 int version, size_t structsize));
894 EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
895 int version, size_t structsize));
896 /* Destruction of JPEG compression objects */
897 EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
898 EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
900 /* Standard data source and destination managers: stdio streams. */
901 /* Caller is responsible for opening the file before and closing after. */
902 EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
903 EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
905 /* Default parameter setup for compression */
906 EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
907 /* Compression parameter setup aids */
908 EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
909 J_COLOR_SPACE colorspace));
910 EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
911 EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
912 boolean force_baseline));
913 EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
915 boolean force_baseline));
916 EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
917 const unsigned int *basic_table,
919 boolean force_baseline));
920 EXTERN(int) jpeg_quality_scaling JPP((int quality));
921 EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
922 EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
924 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
925 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
927 /* Main entry points for compression */
928 EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
929 boolean write_all_tables));
930 EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
931 JSAMPARRAY scanlines,
932 JDIMENSION num_lines));
933 EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
935 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
936 EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
938 JDIMENSION num_lines));
940 /* Write a special marker. See libjpeg.doc concerning safe usage. */
941 EXTERN(void) jpeg_write_marker
942 JPP((j_compress_ptr cinfo, int marker,
943 const JOCTET * dataptr, unsigned int datalen));
945 /* Alternate compression function: just write an abbreviated table file */
946 EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
948 /* Decompression startup: read start of JPEG datastream to see what's there */
949 EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
950 boolean require_image));
951 /* Return value is one of: */
952 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
953 #define JPEG_HEADER_OK 1 /* Found valid image datastream */
954 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
955 /* If you pass require_image = TRUE (normal case), you need not check for
956 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
957 * JPEG_SUSPENDED is only possible if you use a data source module that can
958 * give a suspension return (the stdio source module doesn't).
961 /* Main entry points for decompression */
962 EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
963 EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
964 JSAMPARRAY scanlines,
965 JDIMENSION max_lines));
966 EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
968 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
969 EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
971 JDIMENSION max_lines));
973 /* Additional entry points for buffered-image mode. */
974 EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
975 EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
977 EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
978 EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
979 EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
980 EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
981 /* Return value is one of: */
982 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
983 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
984 #define JPEG_REACHED_EOI 2 /* Reached end of image */
985 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
986 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
988 /* Precalculate output dimensions for current decompression parameters. */
989 EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
991 /* Install a special processing method for COM or APPn markers. */
992 EXTERN(void) jpeg_set_marker_processor
993 JPP((j_decompress_ptr cinfo, int marker_code,
994 jpeg_marker_parser_method routine));
996 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
997 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
998 EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
999 jvirt_barray_ptr * coef_arrays));
1000 EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1001 j_compress_ptr dstinfo));
1003 /* If you choose to abort compression or decompression before completing
1004 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1005 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1006 * if you're done with the JPEG object, but if you want to clean it up and
1007 * reuse it, call this:
1009 EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
1010 EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1012 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1013 * flavor of JPEG object. These may be more convenient in some places.
1015 EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
1016 EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
1018 /* Default restart-marker-resync procedure for use by data source modules */
1019 EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1023 /* These marker codes are exported since applications and data source modules
1024 * are likely to want to use them.
1027 #define JPEG_RST0 0xD0 /* RST0 marker code */
1028 #define JPEG_EOI 0xD9 /* EOI marker code */
1029 #define JPEG_APP0 0xE0 /* APP0 marker code */
1030 #define JPEG_COM 0xFE /* COM marker code */
1033 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1034 * for structure definitions that are never filled in, keep it quiet by
1035 * supplying dummy definitions for the various substructures.
1038 #ifdef INCOMPLETE_TYPES_BROKEN
1039 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1040 struct jvirt_sarray_control { long dummy; };
1041 struct jvirt_barray_control { long dummy; };
1042 struct jpeg_comp_master { long dummy; };
1043 struct jpeg_c_main_controller { long dummy; };
1044 struct jpeg_c_prep_controller { long dummy; };
1045 struct jpeg_c_coef_controller { long dummy; };
1046 struct jpeg_marker_writer { long dummy; };
1047 struct jpeg_color_converter { long dummy; };
1048 struct jpeg_downsampler { long dummy; };
1049 struct jpeg_forward_dct { long dummy; };
1050 struct jpeg_entropy_encoder { long dummy; };
1051 struct jpeg_decomp_master { long dummy; };
1052 struct jpeg_d_main_controller { long dummy; };
1053 struct jpeg_d_coef_controller { long dummy; };
1054 struct jpeg_d_post_controller { long dummy; };
1055 struct jpeg_input_controller { long dummy; };
1056 struct jpeg_marker_reader { long dummy; };
1057 struct jpeg_entropy_decoder { long dummy; };
1058 struct jpeg_inverse_dct { long dummy; };
1059 struct jpeg_upsampler { long dummy; };
1060 struct jpeg_color_deconverter { long dummy; };
1061 struct jpeg_color_quantizer { long dummy; };
1062 #endif /* JPEG_INTERNALS */
1063 #endif /* INCOMPLETE_TYPES_BROKEN */
1067 * The JPEG library modules define JPEG_INTERNALS before including this file.
1068 * The internal structure declarations are read only when that is true.
1069 * Applications using the library should not include jpegint.h, but may wish
1070 * to include jerror.h.
1073 #ifdef JPEG_INTERNALS
1074 #include "jpegint.h" /* fetch private declarations */
1075 #include "jerror.h" /* fetch error codes too */
1078 #endif /* JPEGLIB_H */