1 /*
2 * jpeglib.h
3 *
4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * Modified 2002-2017 by Guido Vollbeding.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
8 *
9 * This file defines the application interface for the JPEG library.
10 * Most applications using the library need only include this file,
11 * and perhaps jerror.h if they want to know the exact error codes.
12 */
13
14 #ifndef JPEGLIB_H
15 #define JPEGLIB_H
16
17 /*
18 * First we include the configuration files that record how this
19 * installation of the JPEG library is set up. jconfig.h can be
20 * generated automatically for many systems. jmorecfg.h contains
21 * manual configuration options that most people need not worry about.
22 */
23
24 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
25 #include "jconfig.h" /* widely used configuration options */
26 #endif
27 #include "jmorecfg.h" /* seldom changed options */
28
29
30 #ifdef __cplusplus
31 #ifndef DONT_USE_EXTERN_C
32 extern "C" {
33 #endif
34 #endif
35
36 /* Version IDs for the JPEG library.
37 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 90".
38 */
39
40 #define JPEG_LIB_VERSION 90 /* Compatibility version 9.0 */
41 #define JPEG_LIB_VERSION_MAJOR 9
42 #define JPEG_LIB_VERSION_MINOR 3
43
44
45 /* Various constants determining the sizes of things.
46 * All of these are specified by the JPEG standard,
47 * so don't change them if you want to be compatible.
48 */
49
50 #define DCTSIZE 8 /* The basic DCT block is 8x8 coefficients */
51 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
52 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
53 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
54 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
55 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
56 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
57 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
58 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
59 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
60 * to handle it. We even let you do this from the jconfig.h file. However,
61 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
62 * sometimes emits noncompliant files doesn't mean you should too.
63 */
64 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
65 #ifndef D_MAX_BLOCKS_IN_MCU
66 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
67 #endif
68
69
70 /* Data structures for images (arrays of samples and of DCT coefficients).
71 * On 80x86 machines, the image arrays are too big for near pointers,
72 * but the pointer arrays can fit in near memory.
73 */
74
75 typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
76 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
77 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
78
79 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
80 typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
81 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
82 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
83
84 typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
85
86
87 /* Types for JPEG compression parameters and working tables. */
88
89
90 /* DCT coefficient quantization tables. */
91
92 typedef struct {
93 /* This array gives the coefficient quantizers in natural array order
94 * (not the zigzag order in which they are stored in a JPEG DQT marker).
95 * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
96 */
97 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
98 /* This field is used only during compression. It's initialized FALSE when
99 * the table is created, and set TRUE when it's been output to the file.
100 * You could suppress output of a table by setting this to TRUE.
101 * (See jpeg_suppress_tables for an example.)
102 */
103 boolean sent_table; /* TRUE when table has been output */
104 } JQUANT_TBL;
105
106
107 /* Huffman coding tables. */
108
109 typedef struct {
110 /* These two fields directly represent the contents of a JPEG DHT marker */
111 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
112 /* length k bits; bits[0] is unused */
113 UINT8 huffval[256]; /* The symbols, in order of incr code length */
114 /* This field is used only during compression. It's initialized FALSE when
115 * the table is created, and set TRUE when it's been output to the file.
116 * You could suppress output of a table by setting this to TRUE.
117 * (See jpeg_suppress_tables for an example.)
118 */
119 boolean sent_table; /* TRUE when table has been output */
120 } JHUFF_TBL;
121
122
123 /* Basic info about one component (color channel). */
124
125 typedef struct {
126 /* These values are fixed over the whole image. */
127 /* For compression, they must be supplied by parameter setup; */
128 /* for decompression, they are read from the SOF marker. */
129 int component_id; /* identifier for this component (0..255) */
130 int component_index; /* its index in SOF or cinfo->comp_info[] */
131 int h_samp_factor; /* horizontal sampling factor (1..4) */
132 int v_samp_factor; /* vertical sampling factor (1..4) */
133 int quant_tbl_no; /* quantization table selector (0..3) */
134 /* These values may vary between scans. */
135 /* For compression, they must be supplied by parameter setup; */
136 /* for decompression, they are read from the SOS marker. */
137 /* The decompressor output side may not use these variables. */
138 int dc_tbl_no; /* DC entropy table selector (0..3) */
139 int ac_tbl_no; /* AC entropy table selector (0..3) */
140
141 /* Remaining fields should be treated as private by applications. */
142
143 /* These values are computed during compression or decompression startup: */
144 /* Component's size in DCT blocks.
145 * Any dummy blocks added to complete an MCU are not counted; therefore
146 * these values do not depend on whether a scan is interleaved or not.
147 */
148 JDIMENSION width_in_blocks;
149 JDIMENSION height_in_blocks;
150 /* Size of a DCT block in samples,
151 * reflecting any scaling we choose to apply during the DCT step.
152 * Values from 1 to 16 are supported.
153 * Note that different components may receive different DCT scalings.
154 */
155 int DCT_h_scaled_size;
156 int DCT_v_scaled_size;
157 /* The downsampled dimensions are the component's actual, unpadded number
158 * of samples at the main buffer (preprocessing/compression interface);
159 * DCT scaling is included, so
160 * downsampled_width =
161 * ceil(image_width * Hi/Hmax * DCT_h_scaled_size/block_size)
162 * and similarly for height.
163 */
164 JDIMENSION downsampled_width; /* actual width in samples */
165 JDIMENSION downsampled_height; /* actual height in samples */
166 /* For decompression, in cases where some of the components will be
167 * ignored (eg grayscale output from YCbCr image), we can skip most
168 * computations for the unused components.
169 * For compression, some of the components will need further quantization
170 * scale by factor of 2 after DCT (eg BG_YCC output from normal RGB input).
171 * The field is first set TRUE for decompression, FALSE for compression
172 * in initial_setup, and then adapted in color conversion setup.
173 */
174 boolean component_needed;
175
176 /* These values are computed before starting a scan of the component. */
177 /* The decompressor output side may not use these variables. */
178 int MCU_width; /* number of blocks per MCU, horizontally */
179 int MCU_height; /* number of blocks per MCU, vertically */
180 int MCU_blocks; /* MCU_width * MCU_height */
181 int MCU_sample_width; /* MCU width in samples: MCU_width * DCT_h_scaled_size */
182 int last_col_width; /* # of non-dummy blocks across in last MCU */
183 int last_row_height; /* # of non-dummy blocks down in last MCU */
184
185 /* Saved quantization table for component; NULL if none yet saved.
186 * See jdinput.c comments about the need for this information.
187 * This field is currently used only for decompression.
188 */
189 JQUANT_TBL * quant_table;
190
191 /* Private per-component storage for DCT or IDCT subsystem. */
192 void * dct_table;
193 } jpeg_component_info;
194
195
196 /* The script for encoding a multiple-scan file is an array of these: */
197
198 typedef struct {
199 int comps_in_scan; /* number of components encoded in this scan */
200 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
201 int Ss, Se; /* progressive JPEG spectral selection parms */
202 int Ah, Al; /* progressive JPEG successive approx. parms */
203 } jpeg_scan_info;
204
205 /* The decompressor can save APPn and COM markers in a list of these: */
206
207 typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
208
209 struct jpeg_marker_struct {
210 jpeg_saved_marker_ptr next; /* next in list, or NULL */
211 UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */
212 unsigned int original_length; /* # bytes of data in the file */
213 unsigned int data_length; /* # bytes of data saved at data[] */
214 JOCTET FAR * data; /* the data contained in the marker */
215 /* the marker length word is not counted in data_length or original_length */
216 };
217
218 /* Known color spaces. */
219
220 typedef enum {
221 JCS_UNKNOWN, /* error/unspecified */
222 JCS_GRAYSCALE, /* monochrome */
223 JCS_RGB, /* red/green/blue, standard RGB (sRGB) */
224 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV), standard YCC */
225 JCS_CMYK, /* C/M/Y/K */
226 JCS_YCCK, /* Y/Cb/Cr/K */
227 JCS_BG_RGB, /* big gamut red/green/blue, bg-sRGB */
228 JCS_BG_YCC /* big gamut Y/Cb/Cr, bg-sYCC */
229 } J_COLOR_SPACE;
230
231 /* Supported color transforms. */
232
233 typedef enum {
234 JCT_NONE = 0,
235 JCT_SUBTRACT_GREEN = 1
236 } J_COLOR_TRANSFORM;
237
238 /* DCT/IDCT algorithm options. */
239
240 typedef enum {
241 JDCT_ISLOW, /* slow but accurate integer algorithm */
242 JDCT_IFAST, /* faster, less accurate integer method */
243 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
244 } J_DCT_METHOD;
245
246 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
247 #define JDCT_DEFAULT JDCT_ISLOW
248 #endif
249 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
250 #define JDCT_FASTEST JDCT_IFAST
251 #endif
252
253 /* Dithering options for decompression. */
254
255 typedef enum {
256 JDITHER_NONE, /* no dithering */
257 JDITHER_ORDERED, /* simple ordered dither */
258 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
259 } J_DITHER_MODE;
260
261
262 /* Common fields between JPEG compression and decompression master structs. */
263
264 #define jpeg_common_fields \
265 struct jpeg_error_mgr * err; /* Error handler module */\
266 struct jpeg_memory_mgr * mem; /* Memory manager module */\
267 struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
268 void * client_data; /* Available for use by application */\
269 boolean is_decompressor; /* So common code can tell which is which */\
270 int global_state /* For checking call sequence validity */
271
272 /* Routines that are to be used by both halves of the library are declared
273 * to receive a pointer to this structure. There are no actual instances of
274 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
275 */
276 struct jpeg_common_struct {
277 jpeg_common_fields; /* Fields common to both master struct types */
278 /* Additional fields follow in an actual jpeg_compress_struct or
279 * jpeg_decompress_struct. All three structs must agree on these
280 * initial fields! (This would be a lot cleaner in C++.)
281 */
282 };
283
284 typedef struct jpeg_common_struct * j_common_ptr;
285 typedef struct jpeg_compress_struct * j_compress_ptr;
286 typedef struct jpeg_decompress_struct * j_decompress_ptr;
287
288
289 /* Master record for a compression instance */
290
291 struct jpeg_compress_struct {
292 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
293
294 /* Destination for compressed data */
295 struct jpeg_destination_mgr * dest;
296
297 /* Description of source image --- these fields must be filled in by
298 * outer application before starting compression. in_color_space must
299 * be correct before you can even call jpeg_set_defaults().
300 */
301
302 JDIMENSION image_width; /* input image width */
303 JDIMENSION image_height; /* input image height */
304 int input_components; /* # of color components in input image */
305 J_COLOR_SPACE in_color_space; /* colorspace of input image */
306
307 double input_gamma; /* image gamma of input image */
308
309 /* Compression parameters --- these fields must be set before calling
310 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
311 * initialize everything to reasonable defaults, then changing anything
312 * the application specifically wants to change. That way you won't get
313 * burnt when new parameters are added. Also note that there are several
314 * helper routines to simplify changing parameters.
315 */
316
317 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
318
319 JDIMENSION jpeg_width; /* scaled JPEG image width */
320 JDIMENSION jpeg_height; /* scaled JPEG image height */
321 /* Dimensions of actual JPEG image that will be written to file,
322 * derived from input dimensions by scaling factors above.
323 * These fields are computed by jpeg_start_compress().
324 * You can also use jpeg_calc_jpeg_dimensions() to determine these values
325 * in advance of calling jpeg_start_compress().
326 */
327
328 int data_precision; /* bits of precision in image data */
329
330 int num_components; /* # of color components in JPEG image */
331 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
332
333 jpeg_component_info * comp_info;
334 /* comp_info[i] describes component that appears i'th in SOF */
335
336 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
337 int q_scale_factor[NUM_QUANT_TBLS];
338 /* ptrs to coefficient quantization tables, or NULL if not defined,
339 * and corresponding scale factors (percentage, initialized 100).
340 */
341
342 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
343 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
344 /* ptrs to Huffman coding tables, or NULL if not defined */
345
346 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
347 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
348 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
349
350 int num_scans; /* # of entries in scan_info array */
351 const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
352 /* The default value of scan_info is NULL, which causes a single-scan
353 * sequential JPEG file to be emitted. To create a multi-scan file,
354 * set num_scans and scan_info to point to an array of scan definitions.
355 */
356
357 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
358 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
359 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
360 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
361 boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
362 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
363 J_DCT_METHOD dct_method; /* DCT algorithm selector */
364
365 /* The restart interval can be specified in absolute MCUs by setting
366 * restart_interval, or in MCU rows by setting restart_in_rows
367 * (in which case the correct restart_interval will be figured
368 * for each scan).
369 */
370 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
371 int restart_in_rows; /* if > 0, MCU rows per restart interval */
372
373 /* Parameters controlling emission of special markers. */
374
375 boolean write_JFIF_header; /* should a JFIF marker be written? */
376 UINT8 JFIF_major_version; /* What to write for the JFIF version number */
377 UINT8 JFIF_minor_version;
378 /* These three values are not used by the JPEG code, merely copied */
379 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
380 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
381 /* ratio is defined by X_density/Y_density even when density_unit=0. */
382 UINT8 density_unit; /* JFIF code for pixel size units */
383 UINT16 X_density; /* Horizontal pixel density */
384 UINT16 Y_density; /* Vertical pixel density */
385 boolean write_Adobe_marker; /* should an Adobe marker be written? */
386
387 J_COLOR_TRANSFORM color_transform;
388 /* Color transform identifier, writes LSE marker if nonzero */
389
390 /* State variable: index of next scanline to be written to
391 * jpeg_write_scanlines(). Application may use this to control its
392 * processing loop, e.g., "while (next_scanline < image_height)".
393 */
394
395 JDIMENSION next_scanline; /* 0 .. image_height-1 */
396
397 /* Remaining fields are known throughout compressor, but generally
398 * should not be touched by a surrounding application.
399 */
400
401 /*
402 * These fields are computed during compression startup
403 */
404 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
405 int max_h_samp_factor; /* largest h_samp_factor */
406 int max_v_samp_factor; /* largest v_samp_factor */
407
408 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
409 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
410
411 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
412 /* The coefficient controller receives data in units of MCU rows as defined
413 * for fully interleaved scans (whether the JPEG file is interleaved or not).
414 * There are v_samp_factor * DCT_v_scaled_size sample rows of each component
415 * in an "iMCU" (interleaved MCU) row.
416 */
417
418 /*
419 * These fields are valid during any one scan.
420 * They describe the components and MCUs actually appearing in the scan.
421 */
422 int comps_in_scan; /* # of JPEG components in this scan */
423 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
424 /* *cur_comp_info[i] describes component that appears i'th in SOS */
425
426 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
427 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
428
429 int blocks_in_MCU; /* # of DCT blocks per MCU */
430 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
431 /* MCU_membership[i] is index in cur_comp_info of component owning */
432 /* i'th block in an MCU */
433
434 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
435
436 int block_size; /* the basic DCT block size: 1..16 */
437 const int * natural_order; /* natural-order position array */
438 int lim_Se; /* min( Se, DCTSIZE2-1 ) */
439
440 /*
441 * Links to compression subobjects (methods and private variables of modules)
442 */
443 struct jpeg_comp_master * master;
444 struct jpeg_c_main_controller * main;
445 struct jpeg_c_prep_controller * prep;
446 struct jpeg_c_coef_controller * coef;
447 struct jpeg_marker_writer * marker;
448 struct jpeg_color_converter * cconvert;
449 struct jpeg_downsampler * downsample;
450 struct jpeg_forward_dct * fdct;
451 struct jpeg_entropy_encoder * entropy;
452 jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
453 int script_space_size;
454 };
455
456
457 /* Master record for a decompression instance */
458
459 struct jpeg_decompress_struct {
460 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
461
462 /* Source of compressed data */
463 struct jpeg_source_mgr * src;
464
465 /* Basic description of image --- filled in by jpeg_read_header(). */
466 /* Application may inspect these values to decide how to process image. */
467
468 JDIMENSION image_width; /* nominal image width (from SOF marker) */
469 JDIMENSION image_height; /* nominal image height */
470 int num_components; /* # of color components in JPEG image */
471 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
472
473 /* Decompression processing parameters --- these fields must be set before
474 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
475 * them to default values.
476 */
477
478 J_COLOR_SPACE out_color_space; /* colorspace for output */
479
480 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
481
482 double output_gamma; /* image gamma wanted in output */
483
484 boolean buffered_image; /* TRUE=multiple output passes */
485 boolean raw_data_out; /* TRUE=downsampled data wanted */
486
487 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
488 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
489 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
490
491 boolean quantize_colors; /* TRUE=colormapped output wanted */
492 /* the following are ignored if not quantize_colors: */
493 J_DITHER_MODE dither_mode; /* type of color dithering to use */
494 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
495 int desired_number_of_colors; /* max # colors to use in created colormap */
496 /* these are significant only in buffered-image mode: */
497 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
498 boolean enable_external_quant;/* enable future use of external colormap */
499 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
500
501 /* Description of actual output image that will be returned to application.
502 * These fields are computed by jpeg_start_decompress().
503 * You can also use jpeg_calc_output_dimensions() to determine these values
504 * in advance of calling jpeg_start_decompress().
505 */
506
507 JDIMENSION output_width; /* scaled image width */
508 JDIMENSION output_height; /* scaled image height */
509 int out_color_components; /* # of color components in out_color_space */
510 int output_components; /* # of color components returned */
511 /* output_components is 1 (a colormap index) when quantizing colors;
512 * otherwise it equals out_color_components.
513 */
514 int rec_outbuf_height; /* min recommended height of scanline buffer */
515 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
516 * high, space and time will be wasted due to unnecessary data copying.
517 * Usually rec_outbuf_height will be 1 or 2, at most 4.
518 */
519
520 /* When quantizing colors, the output colormap is described by these fields.
521 * The application can supply a colormap by setting colormap non-NULL before
522 * calling jpeg_start_decompress; otherwise a colormap is created during
523 * jpeg_start_decompress or jpeg_start_output.
524 * The map has out_color_components rows and actual_number_of_colors columns.
525 */
526 int actual_number_of_colors; /* number of entries in use */
527 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
528
529 /* State variables: these variables indicate the progress of decompression.
530 * The application may examine these but must not modify them.
531 */
532
533 /* Row index of next scanline to be read from jpeg_read_scanlines().
534 * Application may use this to control its processing loop, e.g.,
535 * "while (output_scanline < output_height)".
536 */
537 JDIMENSION output_scanline; /* 0 .. output_height-1 */
538
539 /* Current input scan number and number of iMCU rows completed in scan.
540 * These indicate the progress of the decompressor input side.
541 */
542 int input_scan_number; /* Number of SOS markers seen so far */
543 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
544
545 /* The "output scan number" is the notional scan being displayed by the
546 * output side. The decompressor will not allow output scan/row number
547 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
548 */
549 int output_scan_number; /* Nominal scan number being displayed */
550 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
551
552 /* Current progression status. coef_bits[c][i] indicates the precision
553 * with which component c's DCT coefficient i (in zigzag order) is known.
554 * It is -1 when no data has yet been received, otherwise it is the point
555 * transform (shift) value for the most recent scan of the coefficient
556 * (thus, 0 at completion of the progression).
557 * This pointer is NULL when reading a non-progressive file.
558 */
559 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
560
561 /* Internal JPEG parameters --- the application usually need not look at
562 * these fields. Note that the decompressor output side may not use
563 * any parameters that can change between scans.
564 */
565
566 /* Quantization and Huffman tables are carried forward across input
567 * datastreams when processing abbreviated JPEG datastreams.
568 */
569
570 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
571 /* ptrs to coefficient quantization tables, or NULL if not defined */
572
573 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
574 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
575 /* ptrs to Huffman coding tables, or NULL if not defined */
576
577 /* These parameters are never carried across datastreams, since they
578 * are given in SOF/SOS markers or defined to be reset by SOI.
579 */
580
581 int data_precision; /* bits of precision in image data */
582
583 jpeg_component_info * comp_info;
584 /* comp_info[i] describes component that appears i'th in SOF */
585
586 boolean is_baseline; /* TRUE if Baseline SOF0 encountered */
587 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
588 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
589
590 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
591 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
592 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
593
594 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
595
596 /* These fields record data obtained from optional markers recognized by
597 * the JPEG library.
598 */
599 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
600 /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
601 UINT8 JFIF_major_version; /* JFIF version number */
602 UINT8 JFIF_minor_version;
603 UINT8 density_unit; /* JFIF code for pixel size units */
604 UINT16 X_density; /* Horizontal pixel density */
605 UINT16 Y_density; /* Vertical pixel density */
606 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
607 UINT8 Adobe_transform; /* Color transform code from Adobe marker */
608
609 J_COLOR_TRANSFORM color_transform;
610 /* Color transform identifier derived from LSE marker, otherwise zero */
611
612 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
613
614 /* Aside from the specific data retained from APPn markers known to the
615 * library, the uninterpreted contents of any or all APPn and COM markers
616 * can be saved in a list for examination by the application.
617 */
618 jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
619
620 /* Remaining fields are known throughout decompressor, but generally
621 * should not be touched by a surrounding application.
622 */
623
624 /*
625 * These fields are computed during decompression startup
626 */
627 int max_h_samp_factor; /* largest h_samp_factor */
628 int max_v_samp_factor; /* largest v_samp_factor */
629
630 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
631 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
632
633 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
634 /* The coefficient controller's input and output progress is measured in
635 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
636 * in fully interleaved JPEG scans, but are used whether the scan is
637 * interleaved or not. We define an iMCU row as v_samp_factor DCT block
638 * rows of each component. Therefore, the IDCT output contains
639 * v_samp_factor * DCT_v_scaled_size sample rows of a component per iMCU row.
640 */
641
642 JSAMPLE * sample_range_limit; /* table for fast range-limiting */
643
644 /*
645 * These fields are valid during any one scan.
646 * They describe the components and MCUs actually appearing in the scan.
647 * Note that the decompressor output side must not use these fields.
648 */
649 int comps_in_scan; /* # of JPEG components in this scan */
650 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
651 /* *cur_comp_info[i] describes component that appears i'th in SOS */
652
653 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
654 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
655
656 int blocks_in_MCU; /* # of DCT blocks per MCU */
657 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
658 /* MCU_membership[i] is index in cur_comp_info of component owning */
659 /* i'th block in an MCU */
660
661 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
662
663 /* These fields are derived from Se of first SOS marker.
664 */
665 int block_size; /* the basic DCT block size: 1..16 */
666 const int * natural_order; /* natural-order position array for entropy decode */
667 int lim_Se; /* min( Se, DCTSIZE2-1 ) for entropy decode */
668
669 /* This field is shared between entropy decoder and marker parser.
670 * It is either zero or the code of a JPEG marker that has been
671 * read from the data source, but has not yet been processed.
672 */
673 int unread_marker;
674
675 /*
676 * Links to decompression subobjects (methods, private variables of modules)
677 */
678 struct jpeg_decomp_master * master;
679 struct jpeg_d_main_controller * main;
680 struct jpeg_d_coef_controller * coef;
681 struct jpeg_d_post_controller * post;
682 struct jpeg_input_controller * inputctl;
683 struct jpeg_marker_reader * marker;
684 struct jpeg_entropy_decoder * entropy;
685 struct jpeg_inverse_dct * idct;
686 struct jpeg_upsampler * upsample;
687 struct jpeg_color_deconverter * cconvert;
688 struct jpeg_color_quantizer * cquantize;
689 };
690
691
692 /* "Object" declarations for JPEG modules that may be supplied or called
693 * directly by the surrounding application.
694 * As with all objects in the JPEG library, these structs only define the
695 * publicly visible methods and state variables of a module. Additional
696 * private fields may exist after the public ones.
697 */
698
699
700 /* Error handler object */
701
702 struct jpeg_error_mgr {
703 /* Error exit handler: does not return to caller */
704 JMETHOD(noreturn_t, error_exit, (j_common_ptr cinfo));
705 /* Conditionally emit a trace or warning message */
706 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
707 /* Routine that actually outputs a trace or error message */
708 JMETHOD(void, output_message, (j_common_ptr cinfo));
709 /* Format a message string for the most recent JPEG error or message */
710 JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
711 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
712 /* Reset error state variables at start of a new image */
713 JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
714
715 /* The message ID code and any parameters are saved here.
716 * A message can have one string parameter or up to 8 int parameters.
717 */
718 int msg_code;
719 #define JMSG_STR_PARM_MAX 80
720 union {
721 int i[8];
722 char s[JMSG_STR_PARM_MAX];
723 } msg_parm;
724
725 /* Standard state variables for error facility */
726
727 int trace_level; /* max msg_level that will be displayed */
728
729 /* For recoverable corrupt-data errors, we emit a warning message,
730 * but keep going unless emit_message chooses to abort. emit_message
731 * should count warnings in num_warnings. The surrounding application
732 * can check for bad data by seeing if num_warnings is nonzero at the
733 * end of processing.
734 */
735 long num_warnings; /* number of corrupt-data warnings */
736
737 /* These fields point to the table(s) of error message strings.
738 * An application can change the table pointer to switch to a different
739 * message list (typically, to change the language in which errors are
740 * reported). Some applications may wish to add additional error codes
741 * that will be handled by the JPEG library error mechanism; the second
742 * table pointer is used for this purpose.
743 *
744 * First table includes all errors generated by JPEG library itself.
745 * Error code 0 is reserved for a "no such error string" message.
746 */
747 const char * const * jpeg_message_table; /* Library errors */
748 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
749 /* Second table can be added by application (see cjpeg/djpeg for example).
750 * It contains strings numbered first_addon_message..last_addon_message.
751 */
752 const char * const * addon_message_table; /* Non-library errors */
753 int first_addon_message; /* code for first string in addon table */
754 int last_addon_message; /* code for last string in addon table */
755 };
756
757
758 /* Progress monitor object */
759
760 struct jpeg_progress_mgr {
761 JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
762
763 long pass_counter; /* work units completed in this pass */
764 long pass_limit; /* total number of work units in this pass */
765 int completed_passes; /* passes completed so far */
766 int total_passes; /* total number of passes expected */
767 };
768
769
770 /* Data destination object for compression */
771
772 struct jpeg_destination_mgr {
773 JOCTET * next_output_byte; /* => next byte to write in buffer */
774 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
775
776 JMETHOD(void, init_destination, (j_compress_ptr cinfo));
777 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
778 JMETHOD(void, term_destination, (j_compress_ptr cinfo));
779 };
780
781
782 /* Data source object for decompression */
783
784 struct jpeg_source_mgr {
785 const JOCTET * next_input_byte; /* => next byte to read from buffer */
786 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
787
788 JMETHOD(void, init_source, (j_decompress_ptr cinfo));
789 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
790 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
791 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
792 JMETHOD(void, term_source, (j_decompress_ptr cinfo));
793 };
794
795
796 /* Memory manager object.
797 * Allocates "small" objects (a few K total), "large" objects (tens of K),
798 * and "really big" objects (virtual arrays with backing store if needed).
799 * The memory manager does not allow individual objects to be freed; rather,
800 * each created object is assigned to a pool, and whole pools can be freed
801 * at once. This is faster and more convenient than remembering exactly what
802 * to free, especially where malloc()/free() are not too speedy.
803 * NB: alloc routines never return NULL. They exit to error_exit if not
804 * successful.
805 */
806
807 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
808 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
809 #define JPOOL_NUMPOOLS 2
810
811 typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
812 typedef struct jvirt_barray_control * jvirt_barray_ptr;
813
814
815 struct jpeg_memory_mgr {
816 /* Method pointers */
817 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
818 size_t sizeofobject));
819 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
820 size_t sizeofobject));
821 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
822 JDIMENSION samplesperrow,
823 JDIMENSION numrows));
824 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
825 JDIMENSION blocksperrow,
826 JDIMENSION numrows));
827 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
828 int pool_id,
829 boolean pre_zero,
830 JDIMENSION samplesperrow,
831 JDIMENSION numrows,
832 JDIMENSION maxaccess));
833 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
834 int pool_id,
835 boolean pre_zero,
836 JDIMENSION blocksperrow,
837 JDIMENSION numrows,
838 JDIMENSION maxaccess));
839 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
840 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
841 jvirt_sarray_ptr ptr,
842 JDIMENSION start_row,
843 JDIMENSION num_rows,
844 boolean writable));
845 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
846 jvirt_barray_ptr ptr,
847 JDIMENSION start_row,
848 JDIMENSION num_rows,
849 boolean writable));
850 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
851 JMETHOD(void, self_destruct, (j_common_ptr cinfo));
852
853 /* Limit on memory allocation for this JPEG object. (Note that this is
854 * merely advisory, not a guaranteed maximum; it only affects the space
855 * used for virtual-array buffers.) May be changed by outer application
856 * after creating the JPEG object.
857 */
858 long max_memory_to_use;
859
860 /* Maximum allocation request accepted by alloc_large. */
861 long max_alloc_chunk;
862 };
863
864
865 /* Routine signature for application-supplied marker processing methods.
866 * Need not pass marker code since it is stored in cinfo->unread_marker.
867 */
868 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
869
870
871 /* Declarations for routines called by application.
872 * The JPP macro hides prototype parameters from compilers that can't cope.
873 * Note JPP requires double parentheses.
874 */
875
876 #ifdef HAVE_PROTOTYPES
877 #define JPP(arglist) arglist
878 #else
879 #define JPP(arglist) ()
880 #endif
881
882
883 /* Short forms of external names for systems with brain-damaged linkers.
884 * We shorten external names to be unique in the first six letters, which
885 * is good enough for all known systems.
886 * (If your compiler itself needs names to be unique in less than 15
887 * characters, you are out of luck. Get a better compiler.)
888 */
889
890 #ifdef NEED_SHORT_EXTERNAL_NAMES
891 #define jpeg_std_error jStdError
892 #define jpeg_CreateCompress jCreaCompress
893 #define jpeg_CreateDecompress jCreaDecompress
894 #define jpeg_destroy_compress jDestCompress
895 #define jpeg_destroy_decompress jDestDecompress
896 #define jpeg_stdio_dest jStdDest
897 #define jpeg_stdio_src jStdSrc
898 #define jpeg_mem_dest jMemDest
899 #define jpeg_mem_src jMemSrc
900 #define jpeg_set_defaults jSetDefaults
901 #define jpeg_set_colorspace jSetColorspace
902 #define jpeg_default_colorspace jDefColorspace
903 #define jpeg_set_quality jSetQuality
904 #define jpeg_set_linear_quality jSetLQuality
905 #define jpeg_default_qtables jDefQTables
906 #define jpeg_add_quant_table jAddQuantTable
907 #define jpeg_quality_scaling jQualityScaling
908 #define jpeg_simple_progression jSimProgress
909 #define jpeg_suppress_tables jSuppressTables
910 #define jpeg_alloc_quant_table jAlcQTable
911 #define jpeg_alloc_huff_table jAlcHTable
912 #define jpeg_start_compress jStrtCompress
913 #define jpeg_write_scanlines jWrtScanlines
914 #define jpeg_finish_compress jFinCompress
915 #define jpeg_calc_jpeg_dimensions jCjpegDimensions
916 #define jpeg_write_raw_data jWrtRawData
917 #define jpeg_write_marker jWrtMarker
918 #define jpeg_write_m_header jWrtMHeader
919 #define jpeg_write_m_byte jWrtMByte
920 #define jpeg_write_tables jWrtTables
921 #define jpeg_read_header jReadHeader
922 #define jpeg_start_decompress jStrtDecompress
923 #define jpeg_read_scanlines jReadScanlines
924 #define jpeg_finish_decompress jFinDecompress
925 #define jpeg_read_raw_data jReadRawData
926 #define jpeg_has_multiple_scans jHasMultScn
927 #define jpeg_start_output jStrtOutput
928 #define jpeg_finish_output jFinOutput
929 #define jpeg_input_complete jInComplete
930 #define jpeg_new_colormap jNewCMap
931 #define jpeg_consume_input jConsumeInput
932 #define jpeg_core_output_dimensions jCoreDimensions
933 #define jpeg_calc_output_dimensions jCalcDimensions
934 #define jpeg_save_markers jSaveMarkers
935 #define jpeg_set_marker_processor jSetMarker
936 #define jpeg_read_coefficients jReadCoefs
937 #define jpeg_write_coefficients jWrtCoefs
938 #define jpeg_copy_critical_parameters jCopyCrit
939 #define jpeg_abort_compress jAbrtCompress
940 #define jpeg_abort_decompress jAbrtDecompress
941 #define jpeg_abort jAbort
942 #define jpeg_destroy jDestroy
943 #define jpeg_resync_to_restart jResyncRestart
944 #endif /* NEED_SHORT_EXTERNAL_NAMES */
945
946
947 /* Default error-management setup */
948 EXTERN(struct jpeg_error_mgr *) jpeg_std_error
949 JPP((struct jpeg_error_mgr * err));
950
951 /* Initialization of JPEG compression objects.
952 * jpeg_create_compress() and jpeg_create_decompress() are the exported
953 * names that applications should call. These expand to calls on
954 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
955 * passed for version mismatch checking.
956 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
957 */
958 #define jpeg_create_compress(cinfo) \
959 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
960 (size_t) sizeof(struct jpeg_compress_struct))
961 #define jpeg_create_decompress(cinfo) \
962 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
963 (size_t) sizeof(struct jpeg_decompress_struct))
964 EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
965 int version, size_t structsize));
966 EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
967 int version, size_t structsize));
968 /* Destruction of JPEG compression objects */
969 EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
970 EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
971
972 /* Standard data source and destination managers: stdio streams. */
973 /* Caller is responsible for opening the file before and closing after. */
974 EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
975 EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
976
977 /* Data source and destination managers: memory buffers. */
978 EXTERN(void) jpeg_mem_dest JPP((j_compress_ptr cinfo,
979 unsigned char ** outbuffer,
980 unsigned long * outsize));
981 EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo,
982 const unsigned char * inbuffer,
983 unsigned long insize));
984
985 /* Default parameter setup for compression */
986 EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
987 /* Compression parameter setup aids */
988 EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
989 J_COLOR_SPACE colorspace));
990 EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
991 EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
992 boolean force_baseline));
993 EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
994 int scale_factor,
995 boolean force_baseline));
996 EXTERN(void) jpeg_default_qtables JPP((j_compress_ptr cinfo,
997 boolean force_baseline));
998 EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
999 const unsigned int *basic_table,
1000 int scale_factor,
1001 boolean force_baseline));
1002 EXTERN(int) jpeg_quality_scaling JPP((int quality));
1003 EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
1004 EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
1005 boolean suppress));
1006 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
1007 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
1008
1009 /* Main entry points for compression */
1010 EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
1011 boolean write_all_tables));
1012 EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
1013 JSAMPARRAY scanlines,
1014 JDIMENSION num_lines));
1015 EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
1016
1017 /* Precalculate JPEG dimensions for current compression parameters. */
1018 EXTERN(void) jpeg_calc_jpeg_dimensions JPP((j_compress_ptr cinfo));
1019
1020 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
1021 EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
1022 JSAMPIMAGE data,
1023 JDIMENSION num_lines));
1024
1025 /* Write a special marker. See libjpeg.txt concerning safe usage. */
1026 EXTERN(void) jpeg_write_marker
1027 JPP((j_compress_ptr cinfo, int marker,
1028 const JOCTET * dataptr, unsigned int datalen));
1029 /* Same, but piecemeal. */
1030 EXTERN(void) jpeg_write_m_header
1031 JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
1032 EXTERN(void) jpeg_write_m_byte
1033 JPP((j_compress_ptr cinfo, int val));
1034
1035 /* Alternate compression function: just write an abbreviated table file */
1036 EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
1037
1038 /* Decompression startup: read start of JPEG datastream to see what's there */
1039 EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
1040 boolean require_image));
1041 /* Return value is one of: */
1042 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
1043 #define JPEG_HEADER_OK 1 /* Found valid image datastream */
1044 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
1045 /* If you pass require_image = TRUE (normal case), you need not check for
1046 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
1047 * JPEG_SUSPENDED is only possible if you use a data source module that can
1048 * give a suspension return (the stdio source module doesn't).
1049 */
1050
1051 /* Main entry points for decompression */
1052 EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
1053 EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
1054 JSAMPARRAY scanlines,
1055 JDIMENSION max_lines));
1056 EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
1057
1058 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1059 EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
1060 JSAMPIMAGE data,
1061 JDIMENSION max_lines));
1062
1063 /* Additional entry points for buffered-image mode. */
1064 EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
1065 EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
1066 int scan_number));
1067 EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
1068 EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
1069 EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1070 EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
1071 /* Return value is one of: */
1072 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1073 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1074 #define JPEG_REACHED_EOI 2 /* Reached end of image */
1075 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1076 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1077
1078 /* Precalculate output dimensions for current decompression parameters. */
1079 EXTERN(void) jpeg_core_output_dimensions JPP((j_decompress_ptr cinfo));
1080 EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1081
1082 /* Control saving of COM and APPn markers into marker_list. */
1083 EXTERN(void) jpeg_save_markers
1084 JPP((j_decompress_ptr cinfo, int marker_code,
1085 unsigned int length_limit));
1086
1087 /* Install a special processing method for COM or APPn markers. */
1088 EXTERN(void) jpeg_set_marker_processor
1089 JPP((j_decompress_ptr cinfo, int marker_code,
1090 jpeg_marker_parser_method routine));
1091
1092 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1093 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1094 EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1095 jvirt_barray_ptr * coef_arrays));
1096 EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1097 j_compress_ptr dstinfo));
1098
1099 /* If you choose to abort compression or decompression before completing
1100 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1101 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1102 * if you're done with the JPEG object, but if you want to clean it up and
1103 * reuse it, call this:
1104 */
1105 EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
1106 EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1107
1108 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1109 * flavor of JPEG object. These may be more convenient in some places.
1110 */
1111 EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
1112 EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
1113
1114 /* Default restart-marker-resync procedure for use by data source modules */
1115 EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1116 int desired));
1117
1118
1119 /* These marker codes are exported since applications and data source modules
1120 * are likely to want to use them.
1121 */
1122
1123 #define JPEG_RST0 0xD0 /* RST0 marker code */
1124 #define JPEG_EOI 0xD9 /* EOI marker code */
1125 #define JPEG_APP0 0xE0 /* APP0 marker code */
1126 #define JPEG_COM 0xFE /* COM marker code */
1127
1128
1129 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1130 * for structure definitions that are never filled in, keep it quiet by
1131 * supplying dummy definitions for the various substructures.
1132 */
1133
1134 #ifdef INCOMPLETE_TYPES_BROKEN
1135 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1136 struct jvirt_sarray_control { long dummy; };
1137 struct jvirt_barray_control { long dummy; };
1138 struct jpeg_comp_master { long dummy; };
1139 struct jpeg_c_main_controller { long dummy; };
1140 struct jpeg_c_prep_controller { long dummy; };
1141 struct jpeg_c_coef_controller { long dummy; };
1142 struct jpeg_marker_writer { long dummy; };
1143 struct jpeg_color_converter { long dummy; };
1144 struct jpeg_downsampler { long dummy; };
1145 struct jpeg_forward_dct { long dummy; };
1146 struct jpeg_entropy_encoder { long dummy; };
1147 struct jpeg_decomp_master { long dummy; };
1148 struct jpeg_d_main_controller { long dummy; };
1149 struct jpeg_d_coef_controller { long dummy; };
1150 struct jpeg_d_post_controller { long dummy; };
1151 struct jpeg_input_controller { long dummy; };
1152 struct jpeg_marker_reader { long dummy; };
1153 struct jpeg_entropy_decoder { long dummy; };
1154 struct jpeg_inverse_dct { long dummy; };
1155 struct jpeg_upsampler { long dummy; };
1156 struct jpeg_color_deconverter { long dummy; };
1157 struct jpeg_color_quantizer { long dummy; };
1158 #endif /* JPEG_INTERNALS */
1159 #endif /* INCOMPLETE_TYPES_BROKEN */
1160
1161
1162 /*
1163 * The JPEG library modules define JPEG_INTERNALS before including this file.
1164 * The internal structure declarations are read only when that is true.
1165 * Applications using the library should not include jpegint.h, but may wish
1166 * to include jerror.h.
1167 */
1168
1169 #ifdef JPEG_INTERNALS
1170 #include "jpegint.h" /* fetch private declarations */
1171 #include "jerror.h" /* fetch error codes too */
1172 #endif
1173
1174 #ifdef __cplusplus
1175 #ifndef DONT_USE_EXTERN_C
1176 }
1177 #endif
1178 #endif
1179
1180 #endif /* JPEGLIB_H */