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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 * Modifications:
8 * Copyright (C) 2009-2011, 2013, D. R. Commander.
9 * For conditions of distribution and use, see the accompanying README file.
10 *
11 * This file defines the application interface for the JPEG library.
12 * Most applications using the library need only include this file,
13 * and perhaps jerror.h if they want to know the exact error codes.
14 */
15
16#ifndef JPEGLIB_H
17#define JPEGLIB_H
18
19/*
20 * First we include the configuration files that record how this
21 * installation of the JPEG library is set up. jconfig.h can be
22 * generated automatically for many systems. jmorecfg.h contains
23 * manual configuration options that most people need not worry about.
24 */
25
26#ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
27#include "jconfig.h" /* widely used configuration options */
28#endif
29#include "jmorecfg.h" /* seldom changed options */
30
31
32#ifdef __cplusplus
33#ifndef DONT_USE_EXTERN_C
34extern "C" {
35#endif
36#endif
37
38
39/* Various constants determining the sizes of things.
40 * All of these are specified by the JPEG standard, so don't change them
41 * if you want to be compatible.
42 */
43
44#define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
45#define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
46#define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
47#define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
48#define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
49#define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
50#define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
51/* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
52 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
53 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
54 * to handle it. We even let you do this from the jconfig.h file. However,
55 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
56 * sometimes emits noncompliant files doesn't mean you should too.
57 */
58#define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
59#ifndef D_MAX_BLOCKS_IN_MCU
60#define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
61#endif
62
63
64/* Data structures for images (arrays of samples and of DCT coefficients).
65 * On 80x86 machines, the image arrays are too big for near pointers,
66 * but the pointer arrays can fit in near memory.
67 */
68
69typedef JSAMPLE FAR *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 FAR *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 FAR *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 of 1,2,4,8 are likely to be supported. Note that different
148 * 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 FAR * 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 FAR * 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, RGB_GREEN,
221 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,
232 JCS_EXT_XBGR, or JCS_EXT_XRGB during decompression, the X byte is
233 undefined, and in order to ensure the best performance,
234 libjpeg-turbo can set that byte to whatever value it wishes. Use
235 the following colorspace constants to ensure that the X byte is set
236 to 0xFF, so that it can be interpreted as an opaque alpha
237 channel. */
238 JCS_EXT_RGBA, /* red/green/blue/alpha */
239 JCS_EXT_BGRA, /* blue/green/red/alpha */
240 JCS_EXT_ABGR, /* alpha/blue/green/red */
241 JCS_EXT_ARGB /* alpha/red/green/blue */
242} J_COLOR_SPACE;
243
244/* DCT/IDCT algorithm options. */
245
246typedef enum {
247 JDCT_ISLOW, /* slow but accurate integer algorithm */
248 JDCT_IFAST, /* faster, less accurate integer method */
249 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
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 JMETHOD(void, error_exit, (j_common_ptr cinfo));
723 /* Conditionally emit a trace or warning message */
724 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
725 /* Routine that actually outputs a trace or error message */
726 JMETHOD(void, output_message, (j_common_ptr cinfo));
727 /* Format a message string for the most recent JPEG error or message */
728 JMETHOD(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 JMETHOD(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 JMETHOD(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 JMETHOD(void, init_destination, (j_compress_ptr cinfo));
795 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
796 JMETHOD(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 JMETHOD(void, init_source, (j_decompress_ptr cinfo));
807 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
808 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
809 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
810 JMETHOD(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 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
836 size_t sizeofobject));
837 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
838 size_t sizeofobject));
839 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
840 JDIMENSION samplesperrow,
841 JDIMENSION numrows));
842 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
843 JDIMENSION blocksperrow,
844 JDIMENSION numrows));
845 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
846 int pool_id,
847 boolean pre_zero,
848 JDIMENSION samplesperrow,
849 JDIMENSION numrows,
850 JDIMENSION maxaccess));
851 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
852 int pool_id,
853 boolean pre_zero,
854 JDIMENSION blocksperrow,
855 JDIMENSION numrows,
856 JDIMENSION maxaccess));
857 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
858 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
859 jvirt_sarray_ptr ptr,
860 JDIMENSION start_row,
861 JDIMENSION num_rows,
862 boolean writable));
863 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
864 jvirt_barray_ptr ptr,
865 JDIMENSION start_row,
866 JDIMENSION num_rows,
867 boolean writable));
868 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
869 JMETHOD(void, self_destruct, (j_common_ptr cinfo));
870
871 /* Limit on memory allocation for this JPEG object. (Note that this is
872 * merely advisory, not a guaranteed maximum; it only affects the space
873 * used for virtual-array buffers.) May be changed by outer application
874 * after creating the JPEG object.
875 */
876 long max_memory_to_use;
877
878 /* Maximum allocation request accepted by alloc_large. */
879 long max_alloc_chunk;
880};
881
882
883/* Routine signature for application-supplied marker processing methods.
884 * Need not pass marker code since it is stored in cinfo->unread_marker.
885 */
886typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
887
888
889/* Declarations for routines called by application.
890 * The JPP macro hides prototype parameters from compilers that can't cope.
891 * Note JPP requires double parentheses.
892 */
893
894#ifdef HAVE_PROTOTYPES
895#define JPP(arglist) arglist
896#else
897#define JPP(arglist) ()
898#endif
899
900
901/* Short forms of external names for systems with brain-damaged linkers.
902 * We shorten external names to be unique in the first six letters, which
903 * is good enough for all known systems.
904 * (If your compiler itself needs names to be unique in less than 15
905 * characters, you are out of luck. Get a better compiler.)
906 */
907
908#ifdef NEED_SHORT_EXTERNAL_NAMES
909#define jpeg_std_error jStdError
910#define jpeg_CreateCompress jCreaCompress
911#define jpeg_CreateDecompress jCreaDecompress
912#define jpeg_destroy_compress jDestCompress
913#define jpeg_destroy_decompress jDestDecompress
914#define jpeg_stdio_dest jStdDest
915#define jpeg_stdio_src jStdSrc
916#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
917#define jpeg_mem_dest jMemDest
918#define jpeg_mem_src jMemSrc
919#endif
920#define jpeg_set_defaults jSetDefaults
921#define jpeg_set_colorspace jSetColorspace
922#define jpeg_default_colorspace jDefColorspace
923#define jpeg_set_quality jSetQuality
924#define jpeg_set_linear_quality jSetLQuality
925#if JPEG_LIB_VERSION >= 70
926#define jpeg_default_qtables jDefQTables
927#endif
928#define jpeg_add_quant_table jAddQuantTable
929#define jpeg_quality_scaling jQualityScaling
930#define jpeg_simple_progression jSimProgress
931#define jpeg_suppress_tables jSuppressTables
932#define jpeg_alloc_quant_table jAlcQTable
933#define jpeg_alloc_huff_table jAlcHTable
934#define jpeg_start_compress jStrtCompress
935#define jpeg_write_scanlines jWrtScanlines
936#define jpeg_finish_compress jFinCompress
937#if JPEG_LIB_VERSION >= 70
938#define jpeg_calc_jpeg_dimensions jCjpegDimensions
939#endif
940#define jpeg_write_raw_data jWrtRawData
941#define jpeg_write_marker jWrtMarker
942#define jpeg_write_m_header jWrtMHeader
943#define jpeg_write_m_byte jWrtMByte
944#define jpeg_write_tables jWrtTables
945#define jpeg_read_header jReadHeader
946#define jpeg_start_decompress jStrtDecompress
947#define jpeg_read_scanlines jReadScanlines
948#define jpeg_finish_decompress jFinDecompress
949#define jpeg_read_raw_data jReadRawData
950#define jpeg_has_multiple_scans jHasMultScn
951#define jpeg_start_output jStrtOutput
952#define jpeg_finish_output jFinOutput
953#define jpeg_input_complete jInComplete
954#define jpeg_new_colormap jNewCMap
955#define jpeg_consume_input jConsumeInput
956#if JPEG_LIB_VERSION >= 80
957#define jpeg_core_output_dimensions jCoreDimensions
958#endif
959#define jpeg_calc_output_dimensions jCalcDimensions
960#define jpeg_save_markers jSaveMarkers
961#define jpeg_set_marker_processor jSetMarker
962#define jpeg_read_coefficients jReadCoefs
963#define jpeg_write_coefficients jWrtCoefs
964#define jpeg_copy_critical_parameters jCopyCrit
965#define jpeg_abort_compress jAbrtCompress
966#define jpeg_abort_decompress jAbrtDecompress
967#define jpeg_abort jAbort
968#define jpeg_destroy jDestroy
969#define jpeg_resync_to_restart jResyncRestart
970#endif /* NEED_SHORT_EXTERNAL_NAMES */
971
972
973/* Default error-management setup */
974EXTERN(struct jpeg_error_mgr *) jpeg_std_error
975 JPP((struct jpeg_error_mgr * err));
976
977/* Initialization of JPEG compression objects.
978 * jpeg_create_compress() and jpeg_create_decompress() are the exported
979 * names that applications should call. These expand to calls on
980 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
981 * passed for version mismatch checking.
982 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
983 */
984#define jpeg_create_compress(cinfo) \
985 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
986 (size_t) sizeof(struct jpeg_compress_struct))
987#define jpeg_create_decompress(cinfo) \
988 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
989 (size_t) sizeof(struct jpeg_decompress_struct))
990EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
991 int version, size_t structsize));
992EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
993 int version, size_t structsize));
994/* Destruction of JPEG compression objects */
995EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
996EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
997
998/* Standard data source and destination managers: stdio streams. */
999/* Caller is responsible for opening the file before and closing after. */
1000EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
1001EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
1002
1003#if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
1004/* Data source and destination managers: memory buffers. */
1005EXTERN(void) jpeg_mem_dest JPP((j_compress_ptr cinfo,
1006 unsigned char ** outbuffer,
1007 unsigned long * outsize));
1008EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo,
1009 unsigned char * inbuffer,
1010 unsigned long insize));
1011#endif
1012
1013/* Default parameter setup for compression */
1014EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
1015/* Compression parameter setup aids */
1016EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
1017 J_COLOR_SPACE colorspace));
1018EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
1019EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
1020 boolean force_baseline));
1021EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
1022 int scale_factor,
1023 boolean force_baseline));
1024#if JPEG_LIB_VERSION >= 70
1025EXTERN(void) jpeg_default_qtables JPP((j_compress_ptr cinfo,
1026 boolean force_baseline));
1027#endif
1028EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
1029 const unsigned int *basic_table,
1030 int scale_factor,
1031 boolean force_baseline));
1032EXTERN(int) jpeg_quality_scaling JPP((int quality));
1033EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
1034EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
1035 boolean suppress));
1036EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
1037EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
1038
1039/* Main entry points for compression */
1040EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
1041 boolean write_all_tables));
1042EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
1043 JSAMPARRAY scanlines,
1044 JDIMENSION num_lines));
1045EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
1046
1047#if JPEG_LIB_VERSION >= 70
1048/* Precalculate JPEG dimensions for current compression parameters. */
1049EXTERN(void) jpeg_calc_jpeg_dimensions JPP((j_compress_ptr cinfo));
1050#endif
1051
1052/* Replaces jpeg_write_scanlines when writing raw downsampled data. */
1053EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
1054 JSAMPIMAGE data,
1055 JDIMENSION num_lines));
1056
1057/* Write a special marker. See libjpeg.txt concerning safe usage. */
1058EXTERN(void) jpeg_write_marker
1059 JPP((j_compress_ptr cinfo, int marker,
1060 const JOCTET * dataptr, unsigned int datalen));
1061/* Same, but piecemeal. */
1062EXTERN(void) jpeg_write_m_header
1063 JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
1064EXTERN(void) jpeg_write_m_byte
1065 JPP((j_compress_ptr cinfo, int val));
1066
1067/* Alternate compression function: just write an abbreviated table file */
1068EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
1069
1070/* Decompression startup: read start of JPEG datastream to see what's there */
1071EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
1072 boolean require_image));
1073/* Return value is one of: */
1074#define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
1075#define JPEG_HEADER_OK 1 /* Found valid image datastream */
1076#define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
1077/* If you pass require_image = TRUE (normal case), you need not check for
1078 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
1079 * JPEG_SUSPENDED is only possible if you use a data source module that can
1080 * give a suspension return (the stdio source module doesn't).
1081 */
1082
1083/* Main entry points for decompression */
1084EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
1085EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
1086 JSAMPARRAY scanlines,
1087 JDIMENSION max_lines));
1088EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
1089
1090/* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1091EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
1092 JSAMPIMAGE data,
1093 JDIMENSION max_lines));
1094
1095/* Additional entry points for buffered-image mode. */
1096EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
1097EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
1098 int scan_number));
1099EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
1100EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
1101EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1102EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
1103/* Return value is one of: */
1104/* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1105#define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1106#define JPEG_REACHED_EOI 2 /* Reached end of image */
1107#define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1108#define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1109
1110/* Precalculate output dimensions for current decompression parameters. */
1111#if JPEG_LIB_VERSION >= 80
1112EXTERN(void) jpeg_core_output_dimensions JPP((j_decompress_ptr cinfo));
1113#endif
1114EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1115
1116/* Control saving of COM and APPn markers into marker_list. */
1117EXTERN(void) jpeg_save_markers
1118 JPP((j_decompress_ptr cinfo, int marker_code,
1119 unsigned int length_limit));
1120
1121/* Install a special processing method for COM or APPn markers. */
1122EXTERN(void) jpeg_set_marker_processor
1123 JPP((j_decompress_ptr cinfo, int marker_code,
1124 jpeg_marker_parser_method routine));
1125
1126/* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1127EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1128EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1129 jvirt_barray_ptr * coef_arrays));
1130EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1131 j_compress_ptr dstinfo));
1132
1133/* If you choose to abort compression or decompression before completing
1134 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1135 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1136 * if you're done with the JPEG object, but if you want to clean it up and
1137 * reuse it, call this:
1138 */
1139EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
1140EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1141
1142/* Generic versions of jpeg_abort and jpeg_destroy that work on either
1143 * flavor of JPEG object. These may be more convenient in some places.
1144 */
1145EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
1146EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
1147
1148/* Default restart-marker-resync procedure for use by data source modules */
1149EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1150 int desired));
1151
1152
1153/* These marker codes are exported since applications and data source modules
1154 * are likely to want to use them.
1155 */
1156
1157#define JPEG_RST0 0xD0 /* RST0 marker code */
1158#define JPEG_EOI 0xD9 /* EOI marker code */
1159#define JPEG_APP0 0xE0 /* APP0 marker code */
1160#define JPEG_COM 0xFE /* COM marker code */
1161
1162
1163/* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1164 * for structure definitions that are never filled in, keep it quiet by
1165 * supplying dummy definitions for the various substructures.
1166 */
1167
1168#ifdef INCOMPLETE_TYPES_BROKEN
1169#ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1170struct jvirt_sarray_control { long dummy; };
1171struct jvirt_barray_control { long dummy; };
1172struct jpeg_comp_master { long dummy; };
1173struct jpeg_c_main_controller { long dummy; };
1174struct jpeg_c_prep_controller { long dummy; };
1175struct jpeg_c_coef_controller { long dummy; };
1176struct jpeg_marker_writer { long dummy; };
1177struct jpeg_color_converter { long dummy; };
1178struct jpeg_downsampler { long dummy; };
1179struct jpeg_forward_dct { long dummy; };
1180struct jpeg_entropy_encoder { long dummy; };
1181struct jpeg_decomp_master { long dummy; };
1182struct jpeg_d_main_controller { long dummy; };
1183struct jpeg_d_coef_controller { long dummy; };
1184struct jpeg_d_post_controller { long dummy; };
1185struct jpeg_input_controller { long dummy; };
1186struct jpeg_marker_reader { long dummy; };
1187struct jpeg_entropy_decoder { long dummy; };
1188struct jpeg_inverse_dct { long dummy; };
1189struct jpeg_upsampler { long dummy; };
1190struct jpeg_color_deconverter { long dummy; };
1191struct jpeg_color_quantizer { long dummy; };
1192#endif /* JPEG_INTERNALS */
1193#endif /* INCOMPLETE_TYPES_BROKEN */
1194
1195
1196/*
1197 * The JPEG library modules define JPEG_INTERNALS before including this file.
1198 * The internal structure declarations are read only when that is true.
1199 * Applications using the library should not include jpegint.h, but may wish
1200 * to include jerror.h.
1201 */
1202
1203#ifdef JPEG_INTERNALS
1204#include "jpegint.h" /* fetch private declarations */
1205#include "jerror.h" /* fetch error codes too */
1206#endif
1207
1208#ifdef __cplusplus
1209#ifndef DONT_USE_EXTERN_C
1210}
1211#endif
1212#endif
1213
1214#endif /* JPEGLIB_H */
1215

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