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