1/*
2 * jpeglib.h
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1998, Thomas G. Lane.
6 * Modified 2002-2009 by Guido Vollbeding.
7 * libjpeg-turbo Modifications:
8 * Copyright (C) 2009-2011, 2013-2014, 2016-2017, 2020, D. R. Commander.
9 * Copyright (C) 2015, Google, Inc.
10 * For conditions of distribution and use, see the accompanying README.ijg
11 * file.
12 *
13 * This file defines the application interface for the JPEG library.
14 * Most applications using the library need only include this file,
15 * and perhaps jerror.h if they want to know the exact error codes.
16 */
17
18#ifndef JPEGLIB_H
19#define JPEGLIB_H
20
21/*
22 * First we include the configuration files that record how this
23 * installation of the JPEG library is set up. jconfig.h can be
24 * generated automatically for many systems. jmorecfg.h contains
25 * manual configuration options that most people need not worry about.
26 */
27
28#ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
29#include "jconfig.h" /* widely used configuration options */
30#endif
31#include "jmorecfg.h" /* seldom changed options */
32
33
34#ifdef __cplusplus
35#ifndef DONT_USE_EXTERN_C
36extern "C" {
37#endif
38#endif
39
40
41/* Various constants determining the sizes of things.
42 * All of these are specified by the JPEG standard, so don't change them
43 * if you want to be compatible.
44 */
45
46#define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
47#define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
48#define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
49#define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
50#define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
51#define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
52#define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
53/* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
54 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
55 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
56 * to handle it. We even let you do this from the jconfig.h file. However,
57 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
58 * sometimes emits noncompliant files doesn't mean you should too.
59 */
60#define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
61#ifndef D_MAX_BLOCKS_IN_MCU
62#define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
63#endif
64
65
66/* Data structures for images (arrays of samples and of DCT coefficients).
67 */
68
69typedef JSAMPLE *JSAMPROW; /* ptr to one image row of pixel samples. */
70typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
71typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
72
73typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
74typedef JBLOCK *JBLOCKROW; /* pointer to one row of coefficient blocks */
75typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
76typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
77
78typedef JCOEF *JCOEFPTR; /* useful in a couple of places */
79
80
81/* Types for JPEG compression parameters and working tables. */
82
83
84/* DCT coefficient quantization tables. */
85
86typedef struct {
87 /* This array gives the coefficient quantizers in natural array order
88 * (not the zigzag order in which they are stored in a JPEG DQT marker).
89 * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
90 */
91 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
92 /* This field is used only during compression. It's initialized FALSE when
93 * the table is created, and set TRUE when it's been output to the file.
94 * You could suppress output of a table by setting this to TRUE.
95 * (See jpeg_suppress_tables for an example.)
96 */
97 boolean sent_table; /* TRUE when table has been output */
98} JQUANT_TBL;
99
100
101/* Huffman coding tables. */
102
103typedef struct {
104 /* These two fields directly represent the contents of a JPEG DHT marker */
105 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
106 /* length k bits; bits[0] is unused */
107 UINT8 huffval[256]; /* The symbols, in order of incr code length */
108 /* This field is used only during compression. It's initialized FALSE when
109 * the table is created, and set TRUE when it's been output to the file.
110 * You could suppress output of a table by setting this to TRUE.
111 * (See jpeg_suppress_tables for an example.)
112 */
113 boolean sent_table; /* TRUE when table has been output */
114} JHUFF_TBL;
115
116
117/* Basic info about one component (color channel). */
118
119typedef struct {
120 /* These values are fixed over the whole image. */
121 /* For compression, they must be supplied by parameter setup; */
122 /* for decompression, they are read from the SOF marker. */
123 int component_id; /* identifier for this component (0..255) */
124 int component_index; /* its index in SOF or cinfo->comp_info[] */
125 int h_samp_factor; /* horizontal sampling factor (1..4) */
126 int v_samp_factor; /* vertical sampling factor (1..4) */
127 int quant_tbl_no; /* quantization table selector (0..3) */
128 /* These values may vary between scans. */
129 /* For compression, they must be supplied by parameter setup; */
130 /* for decompression, they are read from the SOS marker. */
131 /* The decompressor output side may not use these variables. */
132 int dc_tbl_no; /* DC entropy table selector (0..3) */
133 int ac_tbl_no; /* AC entropy table selector (0..3) */
134
135 /* Remaining fields should be treated as private by applications. */
136
137 /* These values are computed during compression or decompression startup: */
138 /* Component's size in DCT blocks.
139 * Any dummy blocks added to complete an MCU are not counted; therefore
140 * these values do not depend on whether a scan is interleaved or not.
141 */
142 JDIMENSION width_in_blocks;
143 JDIMENSION height_in_blocks;
144 /* Size of a DCT block in samples. Always DCTSIZE for compression.
145 * For decompression this is the size of the output from one DCT block,
146 * reflecting any scaling we choose to apply during the IDCT step.
147 * Values from 1 to 16 are supported.
148 * Note that different components may receive different IDCT scalings.
149 */
150#if JPEG_LIB_VERSION >= 70
151 int DCT_h_scaled_size;
152 int DCT_v_scaled_size;
153#else
154 int DCT_scaled_size;
155#endif
156 /* The downsampled dimensions are the component's actual, unpadded number
157 * of samples at the main buffer (preprocessing/compression interface), thus
158 * downsampled_width = ceil(image_width * Hi/Hmax)
159 * and similarly for height. For decompression, IDCT scaling is included, so
160 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_[h_]scaled_size/DCTSIZE)
161 */
162 JDIMENSION downsampled_width; /* actual width in samples */
163 JDIMENSION downsampled_height; /* actual height in samples */
164 /* This flag is used only for decompression. In cases where some of the
165 * components will be ignored (eg grayscale output from YCbCr image),
166 * we can skip most computations for the unused components.
167 */
168 boolean component_needed; /* do we need the value of this component? */
169
170 /* These values are computed before starting a scan of the component. */
171 /* The decompressor output side may not use these variables. */
172 int MCU_width; /* number of blocks per MCU, horizontally */
173 int MCU_height; /* number of blocks per MCU, vertically */
174 int MCU_blocks; /* MCU_width * MCU_height */
175 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_[h_]scaled_size */
176 int last_col_width; /* # of non-dummy blocks across in last MCU */
177 int last_row_height; /* # of non-dummy blocks down in last MCU */
178
179 /* Saved quantization table for component; NULL if none yet saved.
180 * See jdinput.c comments about the need for this information.
181 * This field is currently used only for decompression.
182 */
183 JQUANT_TBL *quant_table;
184
185 /* Private per-component storage for DCT or IDCT subsystem. */
186 void *dct_table;
187} jpeg_component_info;
188
189
190/* The script for encoding a multiple-scan file is an array of these: */
191
192typedef struct {
193 int comps_in_scan; /* number of components encoded in this scan */
194 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
195 int Ss, Se; /* progressive JPEG spectral selection parms */
196 int Ah, Al; /* progressive JPEG successive approx. parms */
197} jpeg_scan_info;
198
199/* The decompressor can save APPn and COM markers in a list of these: */
200
201typedef struct jpeg_marker_struct *jpeg_saved_marker_ptr;
202
203struct jpeg_marker_struct {
204 jpeg_saved_marker_ptr next; /* next in list, or NULL */
205 UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */
206 unsigned int original_length; /* # bytes of data in the file */
207 unsigned int data_length; /* # bytes of data saved at data[] */
208 JOCTET *data; /* the data contained in the marker */
209 /* the marker length word is not counted in data_length or original_length */
210};
211
212/* Known color spaces. */
213
214#define JCS_EXTENSIONS 1
215#define JCS_ALPHA_EXTENSIONS 1
216
217typedef enum {
218 JCS_UNKNOWN, /* error/unspecified */
219 JCS_GRAYSCALE, /* monochrome */
220 JCS_RGB, /* red/green/blue as specified by the RGB_RED,
221 RGB_GREEN, RGB_BLUE, and RGB_PIXELSIZE macros */
222 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
223 JCS_CMYK, /* C/M/Y/K */
224 JCS_YCCK, /* Y/Cb/Cr/K */
225 JCS_EXT_RGB, /* red/green/blue */
226 JCS_EXT_RGBX, /* red/green/blue/x */
227 JCS_EXT_BGR, /* blue/green/red */
228 JCS_EXT_BGRX, /* blue/green/red/x */
229 JCS_EXT_XBGR, /* x/blue/green/red */
230 JCS_EXT_XRGB, /* x/red/green/blue */
231 /* When out_color_space it set to JCS_EXT_RGBX, JCS_EXT_BGRX, JCS_EXT_XBGR,
232 or JCS_EXT_XRGB during decompression, the X byte is undefined, and in
233 order to ensure the best performance, libjpeg-turbo can set that byte to
234 whatever value it wishes. Use the following colorspace constants to
235 ensure that the X byte is set to 0xFF, so that it can be interpreted as an
236 opaque alpha channel. */
237 JCS_EXT_RGBA, /* red/green/blue/alpha */
238 JCS_EXT_BGRA, /* blue/green/red/alpha */
239 JCS_EXT_ABGR, /* alpha/blue/green/red */
240 JCS_EXT_ARGB, /* alpha/red/green/blue */
241 JCS_RGB565 /* 5-bit red/6-bit green/5-bit blue */
242} J_COLOR_SPACE;
243
244/* DCT/IDCT algorithm options. */
245
246typedef enum {
247 JDCT_ISLOW, /* accurate integer method */
248 JDCT_IFAST, /* less accurate integer method [legacy feature] */
249 JDCT_FLOAT /* floating-point method [legacy feature] */
250} J_DCT_METHOD;
251
252#ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
253#define JDCT_DEFAULT JDCT_ISLOW
254#endif
255#ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
256#define JDCT_FASTEST JDCT_IFAST
257#endif
258
259/* Dithering options for decompression. */
260
261typedef enum {
262 JDITHER_NONE, /* no dithering */
263 JDITHER_ORDERED, /* simple ordered dither */
264 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
265} J_DITHER_MODE;
266
267
268/* Common fields between JPEG compression and decompression master structs. */
269
270#define jpeg_common_fields \
271 struct jpeg_error_mgr *err; /* Error handler module */ \
272 struct jpeg_memory_mgr *mem; /* Memory manager module */ \
273 struct jpeg_progress_mgr *progress; /* Progress monitor, or NULL if none */ \
274 void *client_data; /* Available for use by application */ \
275 boolean is_decompressor; /* So common code can tell which is which */ \
276 int global_state /* For checking call sequence validity */
277
278/* Routines that are to be used by both halves of the library are declared
279 * to receive a pointer to this structure. There are no actual instances of
280 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
281 */
282struct jpeg_common_struct {
283 jpeg_common_fields; /* Fields common to both master struct types */
284 /* Additional fields follow in an actual jpeg_compress_struct or
285 * jpeg_decompress_struct. All three structs must agree on these
286 * initial fields! (This would be a lot cleaner in C++.)
287 */
288};
289
290typedef struct jpeg_common_struct *j_common_ptr;
291typedef struct jpeg_compress_struct *j_compress_ptr;
292typedef struct jpeg_decompress_struct *j_decompress_ptr;
293
294
295/* Master record for a compression instance */
296
297struct jpeg_compress_struct {
298 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
299
300 /* Destination for compressed data */
301 struct jpeg_destination_mgr *dest;
302
303 /* Description of source image --- these fields must be filled in by
304 * outer application before starting compression. in_color_space must
305 * be correct before you can even call jpeg_set_defaults().
306 */
307
308 JDIMENSION image_width; /* input image width */
309 JDIMENSION image_height; /* input image height */
310 int input_components; /* # of color components in input image */
311 J_COLOR_SPACE in_color_space; /* colorspace of input image */
312
313 double input_gamma; /* image gamma of input image */
314
315 /* Compression parameters --- these fields must be set before calling
316 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
317 * initialize everything to reasonable defaults, then changing anything
318 * the application specifically wants to change. That way you won't get
319 * burnt when new parameters are added. Also note that there are several
320 * helper routines to simplify changing parameters.
321 */
322
323#if JPEG_LIB_VERSION >= 70
324 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
325
326 JDIMENSION jpeg_width; /* scaled JPEG image width */
327 JDIMENSION jpeg_height; /* scaled JPEG image height */
328 /* Dimensions of actual JPEG image that will be written to file,
329 * derived from input dimensions by scaling factors above.
330 * These fields are computed by jpeg_start_compress().
331 * You can also use jpeg_calc_jpeg_dimensions() to determine these values
332 * in advance of calling jpeg_start_compress().
333 */
334#endif
335
336 int data_precision; /* bits of precision in image data */
337
338 int num_components; /* # of color components in JPEG image */
339 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
340
341 jpeg_component_info *comp_info;
342 /* comp_info[i] describes component that appears i'th in SOF */
343
344 JQUANT_TBL *quant_tbl_ptrs[NUM_QUANT_TBLS];
345#if JPEG_LIB_VERSION >= 70
346 int q_scale_factor[NUM_QUANT_TBLS];
347#endif
348 /* ptrs to coefficient quantization tables, or NULL if not defined,
349 * and corresponding scale factors (percentage, initialized 100).
350 */
351
352 JHUFF_TBL *dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
353 JHUFF_TBL *ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
354 /* ptrs to Huffman coding tables, or NULL if not defined */
355
356 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
357 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
358 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
359
360 int num_scans; /* # of entries in scan_info array */
361 const jpeg_scan_info *scan_info; /* script for multi-scan file, or NULL */
362 /* The default value of scan_info is NULL, which causes a single-scan
363 * sequential JPEG file to be emitted. To create a multi-scan file,
364 * set num_scans and scan_info to point to an array of scan definitions.
365 */
366
367 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
368 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
369 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
370 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
371#if JPEG_LIB_VERSION >= 70
372 boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
373#endif
374 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
375 J_DCT_METHOD dct_method; /* DCT algorithm selector */
376
377 /* The restart interval can be specified in absolute MCUs by setting
378 * restart_interval, or in MCU rows by setting restart_in_rows
379 * (in which case the correct restart_interval will be figured
380 * for each scan).
381 */
382 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
383 int restart_in_rows; /* if > 0, MCU rows per restart interval */
384
385 /* Parameters controlling emission of special markers. */
386
387 boolean write_JFIF_header; /* should a JFIF marker be written? */
388 UINT8 JFIF_major_version; /* What to write for the JFIF version number */
389 UINT8 JFIF_minor_version;
390 /* These three values are not used by the JPEG code, merely copied */
391 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
392 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
393 /* ratio is defined by X_density/Y_density even when density_unit=0. */
394 UINT8 density_unit; /* JFIF code for pixel size units */
395 UINT16 X_density; /* Horizontal pixel density */
396 UINT16 Y_density; /* Vertical pixel density */
397 boolean write_Adobe_marker; /* should an Adobe marker be written? */
398
399 /* State variable: index of next scanline to be written to
400 * jpeg_write_scanlines(). Application may use this to control its
401 * processing loop, e.g., "while (next_scanline < image_height)".
402 */
403
404 JDIMENSION next_scanline; /* 0 .. image_height-1 */
405
406 /* Remaining fields are known throughout compressor, but generally
407 * should not be touched by a surrounding application.
408 */
409
410 /*
411 * These fields are computed during compression startup
412 */
413 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
414 int max_h_samp_factor; /* largest h_samp_factor */
415 int max_v_samp_factor; /* largest v_samp_factor */
416
417#if JPEG_LIB_VERSION >= 70
418 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
419 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
420#endif
421
422 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
423 /* The coefficient controller receives data in units of MCU rows as defined
424 * for fully interleaved scans (whether the JPEG file is interleaved or not).
425 * There are v_samp_factor * DCTSIZE sample rows of each component in an
426 * "iMCU" (interleaved MCU) row.
427 */
428
429 /*
430 * These fields are valid during any one scan.
431 * They describe the components and MCUs actually appearing in the scan.
432 */
433 int comps_in_scan; /* # of JPEG components in this scan */
434 jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN];
435 /* *cur_comp_info[i] describes component that appears i'th in SOS */
436
437 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
438 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
439
440 int blocks_in_MCU; /* # of DCT blocks per MCU */
441 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
442 /* MCU_membership[i] is index in cur_comp_info of component owning */
443 /* i'th block in an MCU */
444
445 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
446
447#if JPEG_LIB_VERSION >= 80
448 int block_size; /* the basic DCT block size: 1..16 */
449 const int *natural_order; /* natural-order position array */
450 int lim_Se; /* min( Se, DCTSIZE2-1 ) */
451#endif
452
453 /*
454 * Links to compression subobjects (methods and private variables of modules)
455 */
456 struct jpeg_comp_master *master;
457 struct jpeg_c_main_controller *main;
458 struct jpeg_c_prep_controller *prep;
459 struct jpeg_c_coef_controller *coef;
460 struct jpeg_marker_writer *marker;
461 struct jpeg_color_converter *cconvert;
462 struct jpeg_downsampler *downsample;
463 struct jpeg_forward_dct *fdct;
464 struct jpeg_entropy_encoder *entropy;
465 jpeg_scan_info *script_space; /* workspace for jpeg_simple_progression */
466 int script_space_size;
467};
468
469
470/* Master record for a decompression instance */
471
472struct jpeg_decompress_struct {
473 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
474
475 /* Source of compressed data */
476 struct jpeg_source_mgr *src;
477
478 /* Basic description of image --- filled in by jpeg_read_header(). */
479 /* Application may inspect these values to decide how to process image. */
480
481 JDIMENSION image_width; /* nominal image width (from SOF marker) */
482 JDIMENSION image_height; /* nominal image height */
483 int num_components; /* # of color components in JPEG image */
484 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
485
486 /* Decompression processing parameters --- these fields must be set before
487 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
488 * them to default values.
489 */
490
491 J_COLOR_SPACE out_color_space; /* colorspace for output */
492
493 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
494
495 double output_gamma; /* image gamma wanted in output */
496
497 boolean buffered_image; /* TRUE=multiple output passes */
498 boolean raw_data_out; /* TRUE=downsampled data wanted */
499
500 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
501 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
502 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
503
504 boolean quantize_colors; /* TRUE=colormapped output wanted */
505 /* the following are ignored if not quantize_colors: */
506 J_DITHER_MODE dither_mode; /* type of color dithering to use */
507 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
508 int desired_number_of_colors; /* max # colors to use in created colormap */
509 /* these are significant only in buffered-image mode: */
510 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
511 boolean enable_external_quant;/* enable future use of external colormap */
512 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
513
514 /* Description of actual output image that will be returned to application.
515 * These fields are computed by jpeg_start_decompress().
516 * You can also use jpeg_calc_output_dimensions() to determine these values
517 * in advance of calling jpeg_start_decompress().
518 */
519
520 JDIMENSION output_width; /* scaled image width */
521 JDIMENSION output_height; /* scaled image height */
522 int out_color_components; /* # of color components in out_color_space */
523 int output_components; /* # of color components returned */
524 /* output_components is 1 (a colormap index) when quantizing colors;
525 * otherwise it equals out_color_components.
526 */
527 int rec_outbuf_height; /* min recommended height of scanline buffer */
528 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
529 * high, space and time will be wasted due to unnecessary data copying.
530 * Usually rec_outbuf_height will be 1 or 2, at most 4.
531 */
532
533 /* When quantizing colors, the output colormap is described by these fields.
534 * The application can supply a colormap by setting colormap non-NULL before
535 * calling jpeg_start_decompress; otherwise a colormap is created during
536 * jpeg_start_decompress or jpeg_start_output.
537 * The map has out_color_components rows and actual_number_of_colors columns.
538 */
539 int actual_number_of_colors; /* number of entries in use */
540 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
541
542 /* State variables: these variables indicate the progress of decompression.
543 * The application may examine these but must not modify them.
544 */
545
546 /* Row index of next scanline to be read from jpeg_read_scanlines().
547 * Application may use this to control its processing loop, e.g.,
548 * "while (output_scanline < output_height)".
549 */
550 JDIMENSION output_scanline; /* 0 .. output_height-1 */
551
552 /* Current input scan number and number of iMCU rows completed in scan.
553 * These indicate the progress of the decompressor input side.
554 */
555 int input_scan_number; /* Number of SOS markers seen so far */
556 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
557
558 /* The "output scan number" is the notional scan being displayed by the
559 * output side. The decompressor will not allow output scan/row number
560 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
561 */
562 int output_scan_number; /* Nominal scan number being displayed */
563 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
564
565 /* Current progression status. coef_bits[c][i] indicates the precision
566 * with which component c's DCT coefficient i (in zigzag order) is known.
567 * It is -1 when no data has yet been received, otherwise it is the point
568 * transform (shift) value for the most recent scan of the coefficient
569 * (thus, 0 at completion of the progression).
570 * This pointer is NULL when reading a non-progressive file.
571 */
572 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
573
574 /* Internal JPEG parameters --- the application usually need not look at
575 * these fields. Note that the decompressor output side may not use
576 * any parameters that can change between scans.
577 */
578
579 /* Quantization and Huffman tables are carried forward across input
580 * datastreams when processing abbreviated JPEG datastreams.
581 */
582
583 JQUANT_TBL *quant_tbl_ptrs[NUM_QUANT_TBLS];
584 /* ptrs to coefficient quantization tables, or NULL if not defined */
585
586 JHUFF_TBL *dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
587 JHUFF_TBL *ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
588 /* ptrs to Huffman coding tables, or NULL if not defined */
589
590 /* These parameters are never carried across datastreams, since they
591 * are given in SOF/SOS markers or defined to be reset by SOI.
592 */
593
594 int data_precision; /* bits of precision in image data */
595
596 jpeg_component_info *comp_info;
597 /* comp_info[i] describes component that appears i'th in SOF */
598
599#if JPEG_LIB_VERSION >= 80
600 boolean is_baseline; /* TRUE if Baseline SOF0 encountered */
601#endif
602 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
603 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
604
605 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
606 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
607 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
608
609 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
610
611 /* These fields record data obtained from optional markers recognized by
612 * the JPEG library.
613 */
614 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
615 /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
616 UINT8 JFIF_major_version; /* JFIF version number */
617 UINT8 JFIF_minor_version;
618 UINT8 density_unit; /* JFIF code for pixel size units */
619 UINT16 X_density; /* Horizontal pixel density */
620 UINT16 Y_density; /* Vertical pixel density */
621 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
622 UINT8 Adobe_transform; /* Color transform code from Adobe marker */
623
624 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
625
626 /* Aside from the specific data retained from APPn markers known to the
627 * library, the uninterpreted contents of any or all APPn and COM markers
628 * can be saved in a list for examination by the application.
629 */
630 jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
631
632 /* Remaining fields are known throughout decompressor, but generally
633 * should not be touched by a surrounding application.
634 */
635
636 /*
637 * These fields are computed during decompression startup
638 */
639 int max_h_samp_factor; /* largest h_samp_factor */
640 int max_v_samp_factor; /* largest v_samp_factor */
641
642#if JPEG_LIB_VERSION >= 70
643 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
644 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
645#else
646 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */
647#endif
648
649 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
650 /* The coefficient controller's input and output progress is measured in
651 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
652 * in fully interleaved JPEG scans, but are used whether the scan is
653 * interleaved or not. We define an iMCU row as v_samp_factor DCT block
654 * rows of each component. Therefore, the IDCT output contains
655 * v_samp_factor*DCT_[v_]scaled_size sample rows of a component per iMCU row.
656 */
657
658 JSAMPLE *sample_range_limit; /* table for fast range-limiting */
659
660 /*
661 * These fields are valid during any one scan.
662 * They describe the components and MCUs actually appearing in the scan.
663 * Note that the decompressor output side must not use these fields.
664 */
665 int comps_in_scan; /* # of JPEG components in this scan */
666 jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN];
667 /* *cur_comp_info[i] describes component that appears i'th in SOS */
668
669 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
670 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
671
672 int blocks_in_MCU; /* # of DCT blocks per MCU */
673 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
674 /* MCU_membership[i] is index in cur_comp_info of component owning */
675 /* i'th block in an MCU */
676
677 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
678
679#if JPEG_LIB_VERSION >= 80
680 /* These fields are derived from Se of first SOS marker.
681 */
682 int block_size; /* the basic DCT block size: 1..16 */
683 const int *natural_order; /* natural-order position array for entropy decode */
684 int lim_Se; /* min( Se, DCTSIZE2-1 ) for entropy decode */
685#endif
686
687 /* This field is shared between entropy decoder and marker parser.
688 * It is either zero or the code of a JPEG marker that has been
689 * read from the data source, but has not yet been processed.
690 */
691 int unread_marker;
692
693 /*
694 * Links to decompression subobjects (methods, private variables of modules)
695 */
696 struct jpeg_decomp_master *master;
697 struct jpeg_d_main_controller *main;
698 struct jpeg_d_coef_controller *coef;
699 struct jpeg_d_post_controller *post;
700 struct jpeg_input_controller *inputctl;
701 struct jpeg_marker_reader *marker;
702 struct jpeg_entropy_decoder *entropy;
703 struct jpeg_inverse_dct *idct;
704 struct jpeg_upsampler *upsample;
705 struct jpeg_color_deconverter *cconvert;
706 struct jpeg_color_quantizer *cquantize;
707};
708
709
710/* "Object" declarations for JPEG modules that may be supplied or called
711 * directly by the surrounding application.
712 * As with all objects in the JPEG library, these structs only define the
713 * publicly visible methods and state variables of a module. Additional
714 * private fields may exist after the public ones.
715 */
716
717
718/* Error handler object */
719
720struct jpeg_error_mgr {
721 /* Error exit handler: does not return to caller */
722 void (*error_exit) (j_common_ptr cinfo);
723 /* Conditionally emit a trace or warning message */
724 void (*emit_message) (j_common_ptr cinfo, int msg_level);
725 /* Routine that actually outputs a trace or error message */
726 void (*output_message) (j_common_ptr cinfo);
727 /* Format a message string for the most recent JPEG error or message */
728 void (*format_message) (j_common_ptr cinfo, char *buffer);
729#define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
730 /* Reset error state variables at start of a new image */
731 void (*reset_error_mgr) (j_common_ptr cinfo);
732
733 /* The message ID code and any parameters are saved here.
734 * A message can have one string parameter or up to 8 int parameters.
735 */
736 int msg_code;
737#define JMSG_STR_PARM_MAX 80
738 union {
739 int i[8];
740 char s[JMSG_STR_PARM_MAX];
741 } msg_parm;
742
743 /* Standard state variables for error facility */
744
745 int trace_level; /* max msg_level that will be displayed */
746
747 /* For recoverable corrupt-data errors, we emit a warning message,
748 * but keep going unless emit_message chooses to abort. emit_message
749 * should count warnings in num_warnings. The surrounding application
750 * can check for bad data by seeing if num_warnings is nonzero at the
751 * end of processing.
752 */
753 long num_warnings; /* number of corrupt-data warnings */
754
755 /* These fields point to the table(s) of error message strings.
756 * An application can change the table pointer to switch to a different
757 * message list (typically, to change the language in which errors are
758 * reported). Some applications may wish to add additional error codes
759 * that will be handled by the JPEG library error mechanism; the second
760 * table pointer is used for this purpose.
761 *
762 * First table includes all errors generated by JPEG library itself.
763 * Error code 0 is reserved for a "no such error string" message.
764 */
765 const char * const *jpeg_message_table; /* Library errors */
766 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
767 /* Second table can be added by application (see cjpeg/djpeg for example).
768 * It contains strings numbered first_addon_message..last_addon_message.
769 */
770 const char * const *addon_message_table; /* Non-library errors */
771 int first_addon_message; /* code for first string in addon table */
772 int last_addon_message; /* code for last string in addon table */
773};
774
775
776/* Progress monitor object */
777
778struct jpeg_progress_mgr {
779 void (*progress_monitor) (j_common_ptr cinfo);
780
781 long pass_counter; /* work units completed in this pass */
782 long pass_limit; /* total number of work units in this pass */
783 int completed_passes; /* passes completed so far */
784 int total_passes; /* total number of passes expected */
785};
786
787
788/* Data destination object for compression */
789
790struct jpeg_destination_mgr {
791 JOCTET *next_output_byte; /* => next byte to write in buffer */
792 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
793
794 void (*init_destination) (j_compress_ptr cinfo);
795 boolean (*empty_output_buffer) (j_compress_ptr cinfo);
796 void (*term_destination) (j_compress_ptr cinfo);
797};
798
799
800/* Data source object for decompression */
801
802struct jpeg_source_mgr {
803 const JOCTET *next_input_byte; /* => next byte to read from buffer */
804 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
805
806 void (*init_source) (j_decompress_ptr cinfo);
807 boolean (*fill_input_buffer) (j_decompress_ptr cinfo);
808 void (*skip_input_data) (j_decompress_ptr cinfo, long num_bytes);
809 boolean (*resync_to_restart) (j_decompress_ptr cinfo, int desired);
810 void (*term_source) (j_decompress_ptr cinfo);
811};
812
813
814/* Memory manager object.
815 * Allocates "small" objects (a few K total), "large" objects (tens of K),
816 * and "really big" objects (virtual arrays with backing store if needed).
817 * The memory manager does not allow individual objects to be freed; rather,
818 * each created object is assigned to a pool, and whole pools can be freed
819 * at once. This is faster and more convenient than remembering exactly what
820 * to free, especially where malloc()/free() are not too speedy.
821 * NB: alloc routines never return NULL. They exit to error_exit if not
822 * successful.
823 */
824
825#define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
826#define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
827#define JPOOL_NUMPOOLS 2
828
829typedef struct jvirt_sarray_control *jvirt_sarray_ptr;
830typedef struct jvirt_barray_control *jvirt_barray_ptr;
831
832
833struct jpeg_memory_mgr {
834 /* Method pointers */
835 void *(*alloc_small) (j_common_ptr cinfo, int pool_id, size_t sizeofobject);
836 void *(*alloc_large) (j_common_ptr cinfo, int pool_id,
837 size_t sizeofobject);
838 JSAMPARRAY (*alloc_sarray) (j_common_ptr cinfo, int pool_id,
839 JDIMENSION samplesperrow, JDIMENSION numrows);
840 JBLOCKARRAY (*alloc_barray) (j_common_ptr cinfo, int pool_id,
841 JDIMENSION blocksperrow, JDIMENSION numrows);
842 jvirt_sarray_ptr (*request_virt_sarray) (j_common_ptr cinfo, int pool_id,
843 boolean pre_zero,
844 JDIMENSION samplesperrow,
845 JDIMENSION numrows,
846 JDIMENSION maxaccess);
847 jvirt_barray_ptr (*request_virt_barray) (j_common_ptr cinfo, int pool_id,
848 boolean pre_zero,
849 JDIMENSION blocksperrow,
850 JDIMENSION numrows,
851 JDIMENSION maxaccess);
852 void (*realize_virt_arrays) (j_common_ptr cinfo);
853 JSAMPARRAY (*access_virt_sarray) (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
854 JDIMENSION start_row, JDIMENSION num_rows,
855 boolean writable);
856 JBLOCKARRAY (*access_virt_barray) (j_common_ptr cinfo, jvirt_barray_ptr ptr,
857 JDIMENSION start_row, JDIMENSION num_rows,
858 boolean writable);
859 void (*free_pool) (j_common_ptr cinfo, int pool_id);
860 void (*self_destruct) (j_common_ptr cinfo);
861
862 /* Limit on memory allocation for this JPEG object. (Note that this is
863 * merely advisory, not a guaranteed maximum; it only affects the space
864 * used for virtual-array buffers.) May be changed by outer application
865 * after creating the JPEG object.
866 */
867 long max_memory_to_use;
868
869 /* Maximum allocation request accepted by alloc_large. */
870 long max_alloc_chunk;
871};
872
873
874/* Routine signature for application-supplied marker processing methods.
875 * Need not pass marker code since it is stored in cinfo->unread_marker.
876 */
877typedef boolean (*jpeg_marker_parser_method) (j_decompress_ptr cinfo);
878
879
880/* Originally, this macro was used as a way of defining function prototypes
881 * for both modern compilers as well as older compilers that did not support
882 * prototype parameters. libjpeg-turbo has never supported these older,
883 * non-ANSI compilers, but the macro is still included because there is some
884 * software out there that uses it.
885 */
886
887#define JPP(arglist) arglist
888
889
890/* Default error-management setup */
891EXTERN(struct jpeg_error_mgr *) jpeg_std_error(struct jpeg_error_mgr *err);
892
893/* Initialization of JPEG compression objects.
894 * jpeg_create_compress() and jpeg_create_decompress() are the exported
895 * names that applications should call. These expand to calls on
896 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
897 * passed for version mismatch checking.
898 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
899 */
900#define jpeg_create_compress(cinfo) \
901 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
902 (size_t)sizeof(struct jpeg_compress_struct))
903#define jpeg_create_decompress(cinfo) \
904 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
905 (size_t)sizeof(struct jpeg_decompress_struct))
906EXTERN(void) jpeg_CreateCompress(j_compress_ptr cinfo, int version,
907 size_t structsize);
908EXTERN(void) jpeg_CreateDecompress(j_decompress_ptr cinfo, int version,
909 size_t structsize);
910/* Destruction of JPEG compression objects */
911EXTERN(void) jpeg_destroy_compress(j_compress_ptr cinfo);
912EXTERN(void) jpeg_destroy_decompress(j_decompress_ptr cinfo);
913
914/* Standard data source and destination managers: stdio streams. */
915/* Caller is responsible for opening the file before and closing after. */
916EXTERN(void) jpeg_stdio_dest(j_compress_ptr cinfo, FILE *outfile);
917EXTERN(void) jpeg_stdio_src(j_decompress_ptr cinfo, FILE *infile);
918
919#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
920/* Data source and destination managers: memory buffers. */
921EXTERN(void) jpeg_mem_dest(j_compress_ptr cinfo, unsigned char **outbuffer,
922 unsigned long *outsize);
923EXTERN(void) jpeg_mem_src(j_decompress_ptr cinfo,
924 const unsigned char *inbuffer, unsigned long insize);
925#endif
926
927/* Default parameter setup for compression */
928EXTERN(void) jpeg_set_defaults(j_compress_ptr cinfo);
929/* Compression parameter setup aids */
930EXTERN(void) jpeg_set_colorspace(j_compress_ptr cinfo,
931 J_COLOR_SPACE colorspace);
932EXTERN(void) jpeg_default_colorspace(j_compress_ptr cinfo);
933EXTERN(void) jpeg_set_quality(j_compress_ptr cinfo, int quality,
934 boolean force_baseline);
935EXTERN(void) jpeg_set_linear_quality(j_compress_ptr cinfo, int scale_factor,
936 boolean force_baseline);
937#if JPEG_LIB_VERSION >= 70
938EXTERN(void) jpeg_default_qtables(j_compress_ptr cinfo,
939 boolean force_baseline);
940#endif
941EXTERN(void) jpeg_add_quant_table(j_compress_ptr cinfo, int which_tbl,
942 const unsigned int *basic_table,
943 int scale_factor, boolean force_baseline);
944EXTERN(int) jpeg_quality_scaling(int quality);
945EXTERN(void) jpeg_simple_progression(j_compress_ptr cinfo);
946EXTERN(void) jpeg_suppress_tables(j_compress_ptr cinfo, boolean suppress);
947EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table(j_common_ptr cinfo);
948EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table(j_common_ptr cinfo);
949
950/* Main entry points for compression */
951EXTERN(void) jpeg_start_compress(j_compress_ptr cinfo,
952 boolean write_all_tables);
953EXTERN(JDIMENSION) jpeg_write_scanlines(j_compress_ptr cinfo,
954 JSAMPARRAY scanlines,
955 JDIMENSION num_lines);
956EXTERN(void) jpeg_finish_compress(j_compress_ptr cinfo);
957
958#if JPEG_LIB_VERSION >= 70
959/* Precalculate JPEG dimensions for current compression parameters. */
960EXTERN(void) jpeg_calc_jpeg_dimensions(j_compress_ptr cinfo);
961#endif
962
963/* Replaces jpeg_write_scanlines when writing raw downsampled data. */
964EXTERN(JDIMENSION) jpeg_write_raw_data(j_compress_ptr cinfo, JSAMPIMAGE data,
965 JDIMENSION num_lines);
966
967/* Write a special marker. See libjpeg.txt concerning safe usage. */
968EXTERN(void) jpeg_write_marker(j_compress_ptr cinfo, int marker,
969 const JOCTET *dataptr, unsigned int datalen);
970/* Same, but piecemeal. */
971EXTERN(void) jpeg_write_m_header(j_compress_ptr cinfo, int marker,
972 unsigned int datalen);
973EXTERN(void) jpeg_write_m_byte(j_compress_ptr cinfo, int val);
974
975/* Alternate compression function: just write an abbreviated table file */
976EXTERN(void) jpeg_write_tables(j_compress_ptr cinfo);
977
978/* Write ICC profile. See libjpeg.txt for usage information. */
979EXTERN(void) jpeg_write_icc_profile(j_compress_ptr cinfo,
980 const JOCTET *icc_data_ptr,
981 unsigned int icc_data_len);
982
983
984/* Decompression startup: read start of JPEG datastream to see what's there */
985EXTERN(int) jpeg_read_header(j_decompress_ptr cinfo, boolean require_image);
986/* Return value is one of: */
987#define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
988#define JPEG_HEADER_OK 1 /* Found valid image datastream */
989#define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
990/* If you pass require_image = TRUE (normal case), you need not check for
991 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
992 * JPEG_SUSPENDED is only possible if you use a data source module that can
993 * give a suspension return (the stdio source module doesn't).
994 */
995
996/* Main entry points for decompression */
997EXTERN(boolean) jpeg_start_decompress(j_decompress_ptr cinfo);
998EXTERN(JDIMENSION) jpeg_read_scanlines(j_decompress_ptr cinfo,
999 JSAMPARRAY scanlines,
1000 JDIMENSION max_lines);
1001EXTERN(JDIMENSION) jpeg_skip_scanlines(j_decompress_ptr cinfo,
1002 JDIMENSION num_lines);
1003EXTERN(void) jpeg_crop_scanline(j_decompress_ptr cinfo, JDIMENSION *xoffset,
1004 JDIMENSION *width);
1005EXTERN(boolean) jpeg_finish_decompress(j_decompress_ptr cinfo);
1006
1007/* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1008EXTERN(JDIMENSION) jpeg_read_raw_data(j_decompress_ptr cinfo, JSAMPIMAGE data,
1009 JDIMENSION max_lines);
1010
1011/* Additional entry points for buffered-image mode. */
1012EXTERN(boolean) jpeg_has_multiple_scans(j_decompress_ptr cinfo);
1013EXTERN(boolean) jpeg_start_output(j_decompress_ptr cinfo, int scan_number);
1014EXTERN(boolean) jpeg_finish_output(j_decompress_ptr cinfo);
1015EXTERN(boolean) jpeg_input_complete(j_decompress_ptr cinfo);
1016EXTERN(void) jpeg_new_colormap(j_decompress_ptr cinfo);
1017EXTERN(int) jpeg_consume_input(j_decompress_ptr cinfo);
1018/* Return value is one of: */
1019/* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1020#define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1021#define JPEG_REACHED_EOI 2 /* Reached end of image */
1022#define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1023#define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1024
1025/* Precalculate output dimensions for current decompression parameters. */
1026#if JPEG_LIB_VERSION >= 80
1027EXTERN(void) jpeg_core_output_dimensions(j_decompress_ptr cinfo);
1028#endif
1029EXTERN(void) jpeg_calc_output_dimensions(j_decompress_ptr cinfo);
1030
1031/* Control saving of COM and APPn markers into marker_list. */
1032EXTERN(void) jpeg_save_markers(j_decompress_ptr cinfo, int marker_code,
1033 unsigned int length_limit);
1034
1035/* Install a special processing method for COM or APPn markers. */
1036EXTERN(void) jpeg_set_marker_processor(j_decompress_ptr cinfo,
1037 int marker_code,
1038 jpeg_marker_parser_method routine);
1039
1040/* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1041EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients(j_decompress_ptr cinfo);
1042EXTERN(void) jpeg_write_coefficients(j_compress_ptr cinfo,
1043 jvirt_barray_ptr *coef_arrays);
1044EXTERN(void) jpeg_copy_critical_parameters(j_decompress_ptr srcinfo,
1045 j_compress_ptr dstinfo);
1046
1047/* If you choose to abort compression or decompression before completing
1048 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1049 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1050 * if you're done with the JPEG object, but if you want to clean it up and
1051 * reuse it, call this:
1052 */
1053EXTERN(void) jpeg_abort_compress(j_compress_ptr cinfo);
1054EXTERN(void) jpeg_abort_decompress(j_decompress_ptr cinfo);
1055
1056/* Generic versions of jpeg_abort and jpeg_destroy that work on either
1057 * flavor of JPEG object. These may be more convenient in some places.
1058 */
1059EXTERN(void) jpeg_abort(j_common_ptr cinfo);
1060EXTERN(void) jpeg_destroy(j_common_ptr cinfo);
1061
1062/* Default restart-marker-resync procedure for use by data source modules */
1063EXTERN(boolean) jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired);
1064
1065/* Read ICC profile. See libjpeg.txt for usage information. */
1066EXTERN(boolean) jpeg_read_icc_profile(j_decompress_ptr cinfo,
1067 JOCTET **icc_data_ptr,
1068 unsigned int *icc_data_len);
1069
1070
1071/* These marker codes are exported since applications and data source modules
1072 * are likely to want to use them.
1073 */
1074
1075#define JPEG_RST0 0xD0 /* RST0 marker code */
1076#define JPEG_EOI 0xD9 /* EOI marker code */
1077#define JPEG_APP0 0xE0 /* APP0 marker code */
1078#define JPEG_COM 0xFE /* COM marker code */
1079
1080
1081/* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1082 * for structure definitions that are never filled in, keep it quiet by
1083 * supplying dummy definitions for the various substructures.
1084 */
1085
1086#ifdef INCOMPLETE_TYPES_BROKEN
1087#ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1088struct jvirt_sarray_control { long dummy; };
1089struct jvirt_barray_control { long dummy; };
1090struct jpeg_comp_master { long dummy; };
1091struct jpeg_c_main_controller { long dummy; };
1092struct jpeg_c_prep_controller { long dummy; };
1093struct jpeg_c_coef_controller { long dummy; };
1094struct jpeg_marker_writer { long dummy; };
1095struct jpeg_color_converter { long dummy; };
1096struct jpeg_downsampler { long dummy; };
1097struct jpeg_forward_dct { long dummy; };
1098struct jpeg_entropy_encoder { long dummy; };
1099struct jpeg_decomp_master { long dummy; };
1100struct jpeg_d_main_controller { long dummy; };
1101struct jpeg_d_coef_controller { long dummy; };
1102struct jpeg_d_post_controller { long dummy; };
1103struct jpeg_input_controller { long dummy; };
1104struct jpeg_marker_reader { long dummy; };
1105struct jpeg_entropy_decoder { long dummy; };
1106struct jpeg_inverse_dct { long dummy; };
1107struct jpeg_upsampler { long dummy; };
1108struct jpeg_color_deconverter { long dummy; };
1109struct jpeg_color_quantizer { long dummy; };
1110#endif /* JPEG_INTERNALS */
1111#endif /* INCOMPLETE_TYPES_BROKEN */
1112
1113
1114/*
1115 * The JPEG library modules define JPEG_INTERNALS before including this file.
1116 * The internal structure declarations are read only when that is true.
1117 * Applications using the library should not include jpegint.h, but may wish
1118 * to include jerror.h.
1119 */
1120
1121#ifdef JPEG_INTERNALS
1122#include "jpegint.h" /* fetch private declarations */
1123#include "jerror.h" /* fetch error codes too */
1124#endif
1125
1126#ifdef __cplusplus
1127#ifndef DONT_USE_EXTERN_C
1128}
1129#endif
1130#endif
1131
1132#endif /* JPEGLIB_H */
1133

source code of include/jpeglib.h