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 * Lossless JPEG Modifications:
8 * Copyright (C) 1999, Ken Murchison.
9 * libjpeg-turbo Modifications:
10 * Copyright (C) 2009-2011, 2013-2014, 2016-2017, 2020, 2022-2023,
12 * Copyright (C) 2015, Google, Inc.
13 * For conditions of distribution and use, see the accompanying README.ijg
16 * This file defines the application interface for the JPEG library.
17 * Most applications using the library need only include this file,
18 * and perhaps jerror.h if they want to know the exact error codes.
25 * First we include the configuration files that record how this
26 * installation of the JPEG library is set up. jconfig.h can be
27 * generated automatically for many systems. jmorecfg.h contains
28 * manual configuration options that most people need not worry about.
31 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
32 #include "jconfig.h" /* widely used configuration options */
34 #include "jmorecfg.h" /* seldom changed options */
38 #ifndef DONT_USE_EXTERN_C
44 /* Various constants determining the sizes of things.
45 * All of these are specified by the JPEG standard, so don't change them
46 * if you want to be compatible.
49 /* NOTE: In lossless mode, an MCU contains one or more samples rather than one
50 * or more 8x8 DCT blocks, so the term "data unit" is used to generically
51 * describe a sample in lossless mode or an 8x8 DCT block in lossy mode. To
52 * preserve backward API/ABI compatibility, the field and macro names retain
53 * the "block" terminology.
56 #define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
57 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
58 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
59 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
60 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
61 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
62 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
63 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
64 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
65 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
66 * to handle it. We even let you do this from the jconfig.h file. However,
67 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
68 * sometimes emits noncompliant files doesn't mean you should too.
70 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on data units/MCU */
71 #ifndef D_MAX_BLOCKS_IN_MCU
72 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on data units/MCU */
76 /* Data structures for images (arrays of samples and of DCT coefficients).
79 typedef JSAMPLE *JSAMPROW; /* ptr to one image row of pixel samples. */
80 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
81 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
83 typedef J12SAMPLE *J12SAMPROW; /* ptr to one image row of 12-bit pixel
85 typedef J12SAMPROW *J12SAMPARRAY; /* ptr to some 12-bit sample rows (a 2-D
86 12-bit sample array) */
87 typedef J12SAMPARRAY *J12SAMPIMAGE; /* a 3-D 12-bit sample array: top index is
90 typedef J16SAMPLE *J16SAMPROW; /* ptr to one image row of 16-bit pixel
92 typedef J16SAMPROW *J16SAMPARRAY; /* ptr to some 16-bit sample rows (a 2-D
93 16-bit sample array) */
94 typedef J16SAMPARRAY *J16SAMPIMAGE; /* a 3-D 16-bit sample array: top index is
97 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
98 typedef JBLOCK *JBLOCKROW; /* pointer to one row of coefficient blocks */
99 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
100 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
102 typedef JCOEF *JCOEFPTR; /* useful in a couple of places */
105 /* Types for JPEG compression parameters and working tables. */
108 /* DCT coefficient quantization tables. */
111 /* This array gives the coefficient quantizers in natural array order
112 * (not the zigzag order in which they are stored in a JPEG DQT marker).
113 * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
115 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
116 /* This field is used only during compression. It's initialized FALSE when
117 * the table is created, and set TRUE when it's been output to the file.
118 * You could suppress output of a table by setting this to TRUE.
119 * (See jpeg_suppress_tables for an example.)
121 boolean sent_table; /* TRUE when table has been output */
125 /* Huffman coding tables. */
128 /* These two fields directly represent the contents of a JPEG DHT marker */
129 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
130 /* length k bits; bits[0] is unused */
131 UINT8 huffval[256]; /* The symbols, in order of incr code length */
132 /* This field is used only during compression. It's initialized FALSE when
133 * the table is created, and set TRUE when it's been output to the file.
134 * You could suppress output of a table by setting this to TRUE.
135 * (See jpeg_suppress_tables for an example.)
137 boolean sent_table; /* TRUE when table has been output */
141 /* Basic info about one component (color channel). */
144 /* These values are fixed over the whole image. */
145 /* For compression, they must be supplied by parameter setup; */
146 /* for decompression, they are read from the SOF marker. */
147 int component_id; /* identifier for this component (0..255) */
148 int component_index; /* its index in SOF or cinfo->comp_info[] */
149 int h_samp_factor; /* horizontal sampling factor (1..4) */
150 int v_samp_factor; /* vertical sampling factor (1..4) */
151 int quant_tbl_no; /* quantization table selector (0..3) */
152 /* These values may vary between scans. */
153 /* For compression, they must be supplied by parameter setup; */
154 /* for decompression, they are read from the SOS marker. */
155 /* The decompressor output side may not use these variables. */
156 int dc_tbl_no; /* DC entropy table selector (0..3) */
157 int ac_tbl_no; /* AC entropy table selector (0..3) */
159 /* Remaining fields should be treated as private by applications. */
161 /* These values are computed during compression or decompression startup: */
162 /* Component's size in data units.
163 * In lossy mode, any dummy blocks added to complete an MCU are not counted;
164 * therefore these values do not depend on whether a scan is interleaved or
165 * not. In lossless mode, these are always equal to the image width and
168 JDIMENSION width_in_blocks;
169 JDIMENSION height_in_blocks;
170 /* Size of a data unit in samples. Always DCTSIZE for lossy compression.
171 * For lossy decompression this is the size of the output from one DCT block,
172 * reflecting any scaling we choose to apply during the IDCT step.
173 * Values from 1 to 16 are supported. Note that different components may
174 * receive different IDCT scalings. In lossless mode, this is always equal
177 #if JPEG_LIB_VERSION >= 70
178 int DCT_h_scaled_size;
179 int DCT_v_scaled_size;
183 /* The downsampled dimensions are the component's actual, unpadded number
184 * of samples at the main buffer (preprocessing/compression interface), thus
185 * downsampled_width = ceil(image_width * Hi/Hmax)
186 * and similarly for height. For lossy decompression, IDCT scaling is
188 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_[h_]scaled_size/DCTSIZE)
189 * In lossless mode, these are always equal to the image width and height.
191 JDIMENSION downsampled_width; /* actual width in samples */
192 JDIMENSION downsampled_height; /* actual height in samples */
193 /* This flag is used only for decompression. In cases where some of the
194 * components will be ignored (eg grayscale output from YCbCr image),
195 * we can skip most computations for the unused components.
197 boolean component_needed; /* do we need the value of this component? */
199 /* These values are computed before starting a scan of the component. */
200 /* The decompressor output side may not use these variables. */
201 int MCU_width; /* number of data units per MCU, horizontally */
202 int MCU_height; /* number of data units per MCU, vertically */
203 int MCU_blocks; /* MCU_width * MCU_height */
204 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_[h_]scaled_size */
205 int last_col_width; /* # of non-dummy data units across in last MCU */
206 int last_row_height; /* # of non-dummy data units down in last MCU */
208 /* Saved quantization table for component; NULL if none yet saved.
209 * See jdinput.c comments about the need for this information.
210 * This field is currently used only for decompression.
212 JQUANT_TBL *quant_table;
214 /* Private per-component storage for DCT or IDCT subsystem. */
216 } jpeg_component_info;
219 /* The script for encoding a multiple-scan file is an array of these: */
222 int comps_in_scan; /* number of components encoded in this scan */
223 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
224 int Ss, Se; /* progressive JPEG spectral selection parms
225 (Ss is the predictor selection value in
227 int Ah, Al; /* progressive JPEG successive approx. parms
228 (Al is the point transform value in lossless
232 /* The decompressor can save APPn and COM markers in a list of these: */
234 typedef struct jpeg_marker_struct *jpeg_saved_marker_ptr;
236 struct jpeg_marker_struct {
237 jpeg_saved_marker_ptr next; /* next in list, or NULL */
238 UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */
239 unsigned int original_length; /* # bytes of data in the file */
240 unsigned int data_length; /* # bytes of data saved at data[] */
241 JOCTET *data; /* the data contained in the marker */
242 /* the marker length word is not counted in data_length or original_length */
245 /* Known color spaces. */
247 #define JCS_EXTENSIONS 1
248 #define JCS_ALPHA_EXTENSIONS 1
251 JCS_UNKNOWN, /* error/unspecified */
252 JCS_GRAYSCALE, /* monochrome */
253 JCS_RGB, /* red/green/blue as specified by the RGB_RED,
254 RGB_GREEN, RGB_BLUE, and RGB_PIXELSIZE macros */
255 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
256 JCS_CMYK, /* C/M/Y/K */
257 JCS_YCCK, /* Y/Cb/Cr/K */
258 JCS_EXT_RGB, /* red/green/blue */
259 JCS_EXT_RGBX, /* red/green/blue/x */
260 JCS_EXT_BGR, /* blue/green/red */
261 JCS_EXT_BGRX, /* blue/green/red/x */
262 JCS_EXT_XBGR, /* x/blue/green/red */
263 JCS_EXT_XRGB, /* x/red/green/blue */
264 /* When out_color_space it set to JCS_EXT_RGBX, JCS_EXT_BGRX, JCS_EXT_XBGR,
265 or JCS_EXT_XRGB during decompression, the X byte is undefined, and in
266 order to ensure the best performance, libjpeg-turbo can set that byte to
267 whatever value it wishes. Use the following colorspace constants to
268 ensure that the X byte is set to 0xFF, so that it can be interpreted as an
269 opaque alpha channel. */
270 JCS_EXT_RGBA, /* red/green/blue/alpha */
271 JCS_EXT_BGRA, /* blue/green/red/alpha */
272 JCS_EXT_ABGR, /* alpha/blue/green/red */
273 JCS_EXT_ARGB, /* alpha/red/green/blue */
274 JCS_RGB565 /* 5-bit red/6-bit green/5-bit blue
275 [decompression only] */
278 /* DCT/IDCT algorithm options. */
281 JDCT_ISLOW, /* accurate integer method */
282 JDCT_IFAST, /* less accurate integer method [legacy feature] */
283 JDCT_FLOAT /* floating-point method [legacy feature] */
286 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
287 #define JDCT_DEFAULT JDCT_ISLOW
289 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
290 #define JDCT_FASTEST JDCT_IFAST
293 /* Dithering options for decompression. */
296 JDITHER_NONE, /* no dithering */
297 JDITHER_ORDERED, /* simple ordered dither */
298 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
302 /* Common fields between JPEG compression and decompression master structs. */
304 #define jpeg_common_fields \
305 struct jpeg_error_mgr *err; /* Error handler module */ \
306 struct jpeg_memory_mgr *mem; /* Memory manager module */ \
307 struct jpeg_progress_mgr *progress; /* Progress monitor, or NULL if none */ \
308 void *client_data; /* Available for use by application */ \
309 boolean is_decompressor; /* So common code can tell which is which */ \
310 int global_state /* For checking call sequence validity */
312 /* Routines that are to be used by both halves of the library are declared
313 * to receive a pointer to this structure. There are no actual instances of
314 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
316 struct jpeg_common_struct {
317 jpeg_common_fields; /* Fields common to both master struct types */
318 /* Additional fields follow in an actual jpeg_compress_struct or
319 * jpeg_decompress_struct. All three structs must agree on these
320 * initial fields! (This would be a lot cleaner in C++.)
324 typedef struct jpeg_common_struct *j_common_ptr;
325 typedef struct jpeg_compress_struct *j_compress_ptr;
326 typedef struct jpeg_decompress_struct *j_decompress_ptr;
329 /* Master record for a compression instance */
331 struct jpeg_compress_struct {
332 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
334 /* Destination for compressed data */
335 struct jpeg_destination_mgr *dest;
337 /* Description of source image --- these fields must be filled in by
338 * outer application before starting compression. in_color_space must
339 * be correct before you can even call jpeg_set_defaults().
342 JDIMENSION image_width; /* input image width */
343 JDIMENSION image_height; /* input image height */
344 int input_components; /* # of color components in input image */
345 J_COLOR_SPACE in_color_space; /* colorspace of input image */
347 double input_gamma; /* image gamma of input image */
349 /* Compression parameters --- these fields must be set before calling
350 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
351 * initialize everything to reasonable defaults, then changing anything
352 * the application specifically wants to change. That way you won't get
353 * burnt when new parameters are added. Also note that there are several
354 * helper routines to simplify changing parameters.
357 #if JPEG_LIB_VERSION >= 70
358 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
360 JDIMENSION jpeg_width; /* scaled JPEG image width */
361 JDIMENSION jpeg_height; /* scaled JPEG image height */
362 /* Dimensions of actual JPEG image that will be written to file,
363 * derived from input dimensions by scaling factors above.
364 * These fields are computed by jpeg_start_compress().
365 * You can also use jpeg_calc_jpeg_dimensions() to determine these values
366 * in advance of calling jpeg_start_compress().
370 int data_precision; /* bits of precision in image data */
372 int num_components; /* # of color components in JPEG image */
373 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
375 jpeg_component_info *comp_info;
376 /* comp_info[i] describes component that appears i'th in SOF */
378 JQUANT_TBL *quant_tbl_ptrs[NUM_QUANT_TBLS];
379 #if JPEG_LIB_VERSION >= 70
380 int q_scale_factor[NUM_QUANT_TBLS];
382 /* ptrs to coefficient quantization tables, or NULL if not defined,
383 * and corresponding scale factors (percentage, initialized 100).
386 JHUFF_TBL *dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
387 JHUFF_TBL *ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
388 /* ptrs to Huffman coding tables, or NULL if not defined */
390 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
391 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
392 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
394 int num_scans; /* # of entries in scan_info array */
395 const jpeg_scan_info *scan_info; /* script for multi-scan file, or NULL */
396 /* The default value of scan_info is NULL, which causes a single-scan
397 * sequential JPEG file to be emitted. To create a multi-scan file,
398 * set num_scans and scan_info to point to an array of scan definitions.
401 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
402 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
403 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
404 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
405 #if JPEG_LIB_VERSION >= 70
406 boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
408 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
409 J_DCT_METHOD dct_method; /* DCT algorithm selector */
411 /* The restart interval can be specified in absolute MCUs by setting
412 * restart_interval, or in MCU rows by setting restart_in_rows
413 * (in which case the correct restart_interval will be figured
416 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
417 int restart_in_rows; /* if > 0, MCU rows per restart interval */
419 /* Parameters controlling emission of special markers. */
421 boolean write_JFIF_header; /* should a JFIF marker be written? */
422 UINT8 JFIF_major_version; /* What to write for the JFIF version number */
423 UINT8 JFIF_minor_version;
424 /* These three values are not used by the JPEG code, merely copied */
425 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
426 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
427 /* ratio is defined by X_density/Y_density even when density_unit=0. */
428 UINT8 density_unit; /* JFIF code for pixel size units */
429 UINT16 X_density; /* Horizontal pixel density */
430 UINT16 Y_density; /* Vertical pixel density */
431 boolean write_Adobe_marker; /* should an Adobe marker be written? */
433 /* State variable: index of next scanline to be written to
434 * jpeg_write_scanlines(). Application may use this to control its
435 * processing loop, e.g., "while (next_scanline < image_height)".
438 JDIMENSION next_scanline; /* 0 .. image_height-1 */
440 /* Remaining fields are known throughout compressor, but generally
441 * should not be touched by a surrounding application.
445 * These fields are computed during compression startup
447 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
448 int max_h_samp_factor; /* largest h_samp_factor */
449 int max_v_samp_factor; /* largest v_samp_factor */
451 #if JPEG_LIB_VERSION >= 70
452 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
453 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
456 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coefficient or
457 difference controller */
458 /* The coefficient or difference controller receives data in units of MCU
459 * rows as defined for fully interleaved scans (whether the JPEG file is
460 * interleaved or not). In lossy mode, there are v_samp_factor * DCTSIZE
461 * sample rows of each component in an "iMCU" (interleaved MCU) row. In
462 * lossless mode, total_iMCU_rows is always equal to the image height.
466 * These fields are valid during any one scan.
467 * They describe the components and MCUs actually appearing in the scan.
469 int comps_in_scan; /* # of JPEG components in this scan */
470 jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN];
471 /* *cur_comp_info[i] describes component that appears i'th in SOS */
473 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
474 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
476 int blocks_in_MCU; /* # of data units per MCU */
477 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
478 /* MCU_membership[i] is index in cur_comp_info of component owning */
479 /* i'th data unit in an MCU */
481 int Ss, Se, Ah, Al; /* progressive/lossless JPEG parameters for
484 #if JPEG_LIB_VERSION >= 80
485 int block_size; /* the basic DCT block size: 1..16 */
486 const int *natural_order; /* natural-order position array */
487 int lim_Se; /* min( Se, DCTSIZE2-1 ) */
491 * Links to compression subobjects (methods and private variables of modules)
493 struct jpeg_comp_master *master;
494 struct jpeg_c_main_controller *main;
495 struct jpeg_c_prep_controller *prep;
496 struct jpeg_c_coef_controller *coef;
497 struct jpeg_marker_writer *marker;
498 struct jpeg_color_converter *cconvert;
499 struct jpeg_downsampler *downsample;
500 struct jpeg_forward_dct *fdct;
501 struct jpeg_entropy_encoder *entropy;
502 jpeg_scan_info *script_space; /* workspace for jpeg_simple_progression */
503 int script_space_size;
507 /* Master record for a decompression instance */
509 struct jpeg_decompress_struct {
510 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
512 /* Source of compressed data */
513 struct jpeg_source_mgr *src;
515 /* Basic description of image --- filled in by jpeg_read_header(). */
516 /* Application may inspect these values to decide how to process image. */
518 JDIMENSION image_width; /* nominal image width (from SOF marker) */
519 JDIMENSION image_height; /* nominal image height */
520 int num_components; /* # of color components in JPEG image */
521 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
523 /* Decompression processing parameters --- these fields must be set before
524 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
525 * them to default values.
528 J_COLOR_SPACE out_color_space; /* colorspace for output */
530 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
532 double output_gamma; /* image gamma wanted in output */
534 boolean buffered_image; /* TRUE=multiple output passes */
535 boolean raw_data_out; /* TRUE=downsampled data wanted */
537 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
538 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
539 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
541 boolean quantize_colors; /* TRUE=colormapped output wanted */
542 /* the following are ignored if not quantize_colors: */
543 J_DITHER_MODE dither_mode; /* type of color dithering to use */
544 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
545 int desired_number_of_colors; /* max # colors to use in created colormap */
546 /* these are significant only in buffered-image mode: */
547 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
548 boolean enable_external_quant;/* enable future use of external colormap */
549 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
551 /* Description of actual output image that will be returned to application.
552 * These fields are computed by jpeg_start_decompress().
553 * You can also use jpeg_calc_output_dimensions() to determine these values
554 * in advance of calling jpeg_start_decompress().
557 JDIMENSION output_width; /* scaled image width */
558 JDIMENSION output_height; /* scaled image height */
559 int out_color_components; /* # of color components in out_color_space */
560 int output_components; /* # of color components returned */
561 /* output_components is 1 (a colormap index) when quantizing colors;
562 * otherwise it equals out_color_components.
564 int rec_outbuf_height; /* min recommended height of scanline buffer */
565 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
566 * high, space and time will be wasted due to unnecessary data copying.
567 * Usually rec_outbuf_height will be 1 or 2, at most 4.
570 /* When quantizing colors, the output colormap is described by these fields.
571 * The application can supply a colormap by setting colormap non-NULL before
572 * calling jpeg_start_decompress; otherwise a colormap is created during
573 * jpeg_start_decompress or jpeg_start_output.
574 * The map has out_color_components rows and actual_number_of_colors columns.
576 int actual_number_of_colors; /* number of entries in use */
577 JSAMPARRAY colormap; /* The color map as a 2-D pixel array
578 If data_precision is 12 or 16, then this is
579 actually a J12SAMPARRAY or a J16SAMPARRAY,
580 so callers must type-cast it in order to
581 read/write 12-bit or 16-bit samples from/to
584 /* State variables: these variables indicate the progress of decompression.
585 * The application may examine these but must not modify them.
588 /* Row index of next scanline to be read from jpeg_read_scanlines().
589 * Application may use this to control its processing loop, e.g.,
590 * "while (output_scanline < output_height)".
592 JDIMENSION output_scanline; /* 0 .. output_height-1 */
594 /* Current input scan number and number of iMCU rows completed in scan.
595 * These indicate the progress of the decompressor input side.
597 int input_scan_number; /* Number of SOS markers seen so far */
598 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
600 /* The "output scan number" is the notional scan being displayed by the
601 * output side. The decompressor will not allow output scan/row number
602 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
604 int output_scan_number; /* Nominal scan number being displayed */
605 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
607 /* Current progression status. coef_bits[c][i] indicates the precision
608 * with which component c's DCT coefficient i (in zigzag order) is known.
609 * It is -1 when no data has yet been received, otherwise it is the point
610 * transform (shift) value for the most recent scan of the coefficient
611 * (thus, 0 at completion of the progression).
612 * This pointer is NULL when reading a non-progressive file.
614 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
616 /* Internal JPEG parameters --- the application usually need not look at
617 * these fields. Note that the decompressor output side may not use
618 * any parameters that can change between scans.
621 /* Quantization and Huffman tables are carried forward across input
622 * datastreams when processing abbreviated JPEG datastreams.
625 JQUANT_TBL *quant_tbl_ptrs[NUM_QUANT_TBLS];
626 /* ptrs to coefficient quantization tables, or NULL if not defined */
628 JHUFF_TBL *dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
629 JHUFF_TBL *ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
630 /* ptrs to Huffman coding tables, or NULL if not defined */
632 /* These parameters are never carried across datastreams, since they
633 * are given in SOF/SOS markers or defined to be reset by SOI.
636 int data_precision; /* bits of precision in image data */
638 jpeg_component_info *comp_info;
639 /* comp_info[i] describes component that appears i'th in SOF */
641 #if JPEG_LIB_VERSION >= 80
642 boolean is_baseline; /* TRUE if Baseline SOF0 encountered */
644 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
645 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
647 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
648 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
649 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
651 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
653 /* These fields record data obtained from optional markers recognized by
656 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
657 /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
658 UINT8 JFIF_major_version; /* JFIF version number */
659 UINT8 JFIF_minor_version;
660 UINT8 density_unit; /* JFIF code for pixel size units */
661 UINT16 X_density; /* Horizontal pixel density */
662 UINT16 Y_density; /* Vertical pixel density */
663 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
664 UINT8 Adobe_transform; /* Color transform code from Adobe marker */
666 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
668 /* Aside from the specific data retained from APPn markers known to the
669 * library, the uninterpreted contents of any or all APPn and COM markers
670 * can be saved in a list for examination by the application.
672 jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
674 /* Remaining fields are known throughout decompressor, but generally
675 * should not be touched by a surrounding application.
679 * These fields are computed during decompression startup
681 int max_h_samp_factor; /* largest h_samp_factor */
682 int max_v_samp_factor; /* largest v_samp_factor */
684 #if JPEG_LIB_VERSION >= 70
685 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
686 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
688 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */
691 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
692 /* The coefficient or difference controller's input and output progress is
693 * measured in units of "iMCU" (interleaved MCU) rows. These are the same as
694 * MCU rows in fully interleaved JPEG scans, but are used whether the scan is
695 * interleaved or not. In lossy mode, we define an iMCU row as v_samp_factor
696 * DCT block rows of each component. Therefore, the IDCT output contains
697 * v_samp_factor*DCT_[v_]scaled_size sample rows of a component per iMCU row.
698 * In lossless mode, total_iMCU_rows is always equal to the image height.
701 JSAMPLE *sample_range_limit; /* table for fast range-limiting
702 If data_precision is 12 or 16, then this is
703 actually a J12SAMPLE pointer or a J16SAMPLE
704 pointer, so callers must type-cast it in
705 order to read 12-bit or 16-bit samples from
709 * These fields are valid during any one scan.
710 * They describe the components and MCUs actually appearing in the scan.
711 * Note that the decompressor output side must not use these fields.
713 int comps_in_scan; /* # of JPEG components in this scan */
714 jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN];
715 /* *cur_comp_info[i] describes component that appears i'th in SOS */
717 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
718 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
720 int blocks_in_MCU; /* # of data units per MCU */
721 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
722 /* MCU_membership[i] is index in cur_comp_info of component owning */
723 /* i'th data unit in an MCU */
725 int Ss, Se, Ah, Al; /* progressive/lossless JPEG parameters for
728 #if JPEG_LIB_VERSION >= 80
729 /* These fields are derived from Se of first SOS marker.
731 int block_size; /* the basic DCT block size: 1..16 */
732 const int *natural_order; /* natural-order position array for entropy decode */
733 int lim_Se; /* min( Se, DCTSIZE2-1 ) for entropy decode */
736 /* This field is shared between entropy decoder and marker parser.
737 * It is either zero or the code of a JPEG marker that has been
738 * read from the data source, but has not yet been processed.
743 * Links to decompression subobjects (methods, private variables of modules)
745 struct jpeg_decomp_master *master;
746 struct jpeg_d_main_controller *main;
747 struct jpeg_d_coef_controller *coef;
748 struct jpeg_d_post_controller *post;
749 struct jpeg_input_controller *inputctl;
750 struct jpeg_marker_reader *marker;
751 struct jpeg_entropy_decoder *entropy;
752 struct jpeg_inverse_dct *idct;
753 struct jpeg_upsampler *upsample;
754 struct jpeg_color_deconverter *cconvert;
755 struct jpeg_color_quantizer *cquantize;
759 /* "Object" declarations for JPEG modules that may be supplied or called
760 * directly by the surrounding application.
761 * As with all objects in the JPEG library, these structs only define the
762 * publicly visible methods and state variables of a module. Additional
763 * private fields may exist after the public ones.
767 /* Error handler object */
769 struct jpeg_error_mgr {
770 /* Error exit handler: does not return to caller */
771 void (*error_exit) (j_common_ptr cinfo);
772 /* Conditionally emit a trace or warning message */
773 void (*emit_message) (j_common_ptr cinfo, int msg_level);
774 /* Routine that actually outputs a trace or error message */
775 void (*output_message) (j_common_ptr cinfo);
776 /* Format a message string for the most recent JPEG error or message */
777 void (*format_message) (j_common_ptr cinfo, char *buffer);
778 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
779 /* Reset error state variables at start of a new image */
780 void (*reset_error_mgr) (j_common_ptr cinfo);
782 /* The message ID code and any parameters are saved here.
783 * A message can have one string parameter or up to 8 int parameters.
786 #define JMSG_STR_PARM_MAX 80
789 char s[JMSG_STR_PARM_MAX];
792 /* Standard state variables for error facility */
794 int trace_level; /* max msg_level that will be displayed */
796 /* For recoverable corrupt-data errors, we emit a warning message,
797 * but keep going unless emit_message chooses to abort. emit_message
798 * should count warnings in num_warnings. The surrounding application
799 * can check for bad data by seeing if num_warnings is nonzero at the
802 long num_warnings; /* number of corrupt-data warnings */
804 /* These fields point to the table(s) of error message strings.
805 * An application can change the table pointer to switch to a different
806 * message list (typically, to change the language in which errors are
807 * reported). Some applications may wish to add additional error codes
808 * that will be handled by the JPEG library error mechanism; the second
809 * table pointer is used for this purpose.
811 * First table includes all errors generated by JPEG library itself.
812 * Error code 0 is reserved for a "no such error string" message.
814 const char * const *jpeg_message_table; /* Library errors */
815 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
816 /* Second table can be added by application (see cjpeg/djpeg for example).
817 * It contains strings numbered first_addon_message..last_addon_message.
819 const char * const *addon_message_table; /* Non-library errors */
820 int first_addon_message; /* code for first string in addon table */
821 int last_addon_message; /* code for last string in addon table */
825 /* Progress monitor object */
827 struct jpeg_progress_mgr {
828 void (*progress_monitor) (j_common_ptr cinfo);
830 long pass_counter; /* work units completed in this pass */
831 long pass_limit; /* total number of work units in this pass */
832 int completed_passes; /* passes completed so far */
833 int total_passes; /* total number of passes expected */
837 /* Data destination object for compression */
839 struct jpeg_destination_mgr {
840 JOCTET *next_output_byte; /* => next byte to write in buffer */
841 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
843 void (*init_destination) (j_compress_ptr cinfo);
844 boolean (*empty_output_buffer) (j_compress_ptr cinfo);
845 void (*term_destination) (j_compress_ptr cinfo);
849 /* Data source object for decompression */
851 struct jpeg_source_mgr {
852 const JOCTET *next_input_byte; /* => next byte to read from buffer */
853 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
855 void (*init_source) (j_decompress_ptr cinfo);
856 boolean (*fill_input_buffer) (j_decompress_ptr cinfo);
857 void (*skip_input_data) (j_decompress_ptr cinfo, long num_bytes);
858 boolean (*resync_to_restart) (j_decompress_ptr cinfo, int desired);
859 void (*term_source) (j_decompress_ptr cinfo);
863 /* Memory manager object.
864 * Allocates "small" objects (a few K total), "large" objects (tens of K),
865 * and "really big" objects (virtual arrays with backing store if needed).
866 * The memory manager does not allow individual objects to be freed; rather,
867 * each created object is assigned to a pool, and whole pools can be freed
868 * at once. This is faster and more convenient than remembering exactly what
869 * to free, especially where malloc()/free() are not too speedy.
870 * NB: alloc routines never return NULL. They exit to error_exit if not
874 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
875 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
876 #define JPOOL_NUMPOOLS 2
878 typedef struct jvirt_sarray_control *jvirt_sarray_ptr;
879 typedef struct jvirt_barray_control *jvirt_barray_ptr;
882 struct jpeg_memory_mgr {
883 /* Method pointers */
884 void *(*alloc_small) (j_common_ptr cinfo, int pool_id, size_t sizeofobject);
885 void *(*alloc_large) (j_common_ptr cinfo, int pool_id,
886 size_t sizeofobject);
887 /* If cinfo->data_precision is 12 or 16, then this method and the
888 * access_virt_sarray method actually return a J12SAMPARRAY or a
889 * J16SAMPARRAY, so callers must type-cast the return value in order to
890 * read/write 12-bit or 16-bit samples from/to the array.
892 JSAMPARRAY (*alloc_sarray) (j_common_ptr cinfo, int pool_id,
893 JDIMENSION samplesperrow, JDIMENSION numrows);
894 JBLOCKARRAY (*alloc_barray) (j_common_ptr cinfo, int pool_id,
895 JDIMENSION blocksperrow, JDIMENSION numrows);
896 jvirt_sarray_ptr (*request_virt_sarray) (j_common_ptr cinfo, int pool_id,
898 JDIMENSION samplesperrow,
900 JDIMENSION maxaccess);
901 jvirt_barray_ptr (*request_virt_barray) (j_common_ptr cinfo, int pool_id,
903 JDIMENSION blocksperrow,
905 JDIMENSION maxaccess);
906 void (*realize_virt_arrays) (j_common_ptr cinfo);
907 JSAMPARRAY (*access_virt_sarray) (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
908 JDIMENSION start_row, JDIMENSION num_rows,
910 JBLOCKARRAY (*access_virt_barray) (j_common_ptr cinfo, jvirt_barray_ptr ptr,
911 JDIMENSION start_row, JDIMENSION num_rows,
913 void (*free_pool) (j_common_ptr cinfo, int pool_id);
914 void (*self_destruct) (j_common_ptr cinfo);
916 /* Limit on memory allocation for this JPEG object. (Note that this is
917 * merely advisory, not a guaranteed maximum; it only affects the space
918 * used for virtual-array buffers.) May be changed by outer application
919 * after creating the JPEG object.
921 long max_memory_to_use;
923 /* Maximum allocation request accepted by alloc_large. */
924 long max_alloc_chunk;
928 /* Routine signature for application-supplied marker processing methods.
929 * Need not pass marker code since it is stored in cinfo->unread_marker.
931 typedef boolean (*jpeg_marker_parser_method) (j_decompress_ptr cinfo);
934 /* Originally, this macro was used as a way of defining function prototypes
935 * for both modern compilers as well as older compilers that did not support
936 * prototype parameters. libjpeg-turbo has never supported these older,
937 * non-ANSI compilers, but the macro is still included because there is some
938 * software out there that uses it.
941 #define JPP(arglist) arglist
944 /* Default error-management setup */
945 EXTERN(struct jpeg_error_mgr *) jpeg_std_error(struct jpeg_error_mgr *err);
947 /* Initialization of JPEG compression objects.
948 * jpeg_create_compress() and jpeg_create_decompress() are the exported
949 * names that applications should call. These expand to calls on
950 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
951 * passed for version mismatch checking.
952 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
954 #define jpeg_create_compress(cinfo) \
955 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
956 (size_t)sizeof(struct jpeg_compress_struct))
957 #define jpeg_create_decompress(cinfo) \
958 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
959 (size_t)sizeof(struct jpeg_decompress_struct))
960 EXTERN(void) jpeg_CreateCompress(j_compress_ptr cinfo, int version,
962 EXTERN(void) jpeg_CreateDecompress(j_decompress_ptr cinfo, int version,
964 /* Destruction of JPEG compression objects */
965 EXTERN(void) jpeg_destroy_compress(j_compress_ptr cinfo);
966 EXTERN(void) jpeg_destroy_decompress(j_decompress_ptr cinfo);
968 /* Standard data source and destination managers: stdio streams. */
969 /* Caller is responsible for opening the file before and closing after. */
970 EXTERN(void) jpeg_stdio_dest(j_compress_ptr cinfo, FILE *outfile);
971 EXTERN(void) jpeg_stdio_src(j_decompress_ptr cinfo, FILE *infile);
973 /* Data source and destination managers: memory buffers. */
974 EXTERN(void) jpeg_mem_dest(j_compress_ptr cinfo, unsigned char **outbuffer,
975 unsigned long *outsize);
976 EXTERN(void) jpeg_mem_src(j_decompress_ptr cinfo,
977 const unsigned char *inbuffer, unsigned long insize);
979 /* Default parameter setup for compression */
980 EXTERN(void) jpeg_set_defaults(j_compress_ptr cinfo);
981 /* Compression parameter setup aids */
982 EXTERN(void) jpeg_set_colorspace(j_compress_ptr cinfo,
983 J_COLOR_SPACE colorspace);
984 EXTERN(void) jpeg_default_colorspace(j_compress_ptr cinfo);
985 EXTERN(void) jpeg_set_quality(j_compress_ptr cinfo, int quality,
986 boolean force_baseline);
987 EXTERN(void) jpeg_set_linear_quality(j_compress_ptr cinfo, int scale_factor,
988 boolean force_baseline);
989 #if JPEG_LIB_VERSION >= 70
990 EXTERN(void) jpeg_default_qtables(j_compress_ptr cinfo,
991 boolean force_baseline);
993 EXTERN(void) jpeg_add_quant_table(j_compress_ptr cinfo, int which_tbl,
994 const unsigned int *basic_table,
995 int scale_factor, boolean force_baseline);
996 EXTERN(int) jpeg_quality_scaling(int quality);
997 EXTERN(void) jpeg_enable_lossless(j_compress_ptr cinfo,
998 int predictor_selection_value,
999 int point_transform);
1000 EXTERN(void) jpeg_simple_progression(j_compress_ptr cinfo);
1001 EXTERN(void) jpeg_suppress_tables(j_compress_ptr cinfo, boolean suppress);
1002 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table(j_common_ptr cinfo);
1003 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table(j_common_ptr cinfo);
1005 /* Main entry points for compression */
1006 EXTERN(void) jpeg_start_compress(j_compress_ptr cinfo,
1007 boolean write_all_tables);
1008 EXTERN(JDIMENSION) jpeg_write_scanlines(j_compress_ptr cinfo,
1009 JSAMPARRAY scanlines,
1010 JDIMENSION num_lines);
1011 EXTERN(JDIMENSION) jpeg12_write_scanlines(j_compress_ptr cinfo,
1012 J12SAMPARRAY scanlines,
1013 JDIMENSION num_lines);
1014 EXTERN(JDIMENSION) jpeg16_write_scanlines(j_compress_ptr cinfo,
1015 J16SAMPARRAY scanlines,
1016 JDIMENSION num_lines);
1017 EXTERN(void) jpeg_finish_compress(j_compress_ptr cinfo);
1019 #if JPEG_LIB_VERSION >= 70
1020 /* Precalculate JPEG dimensions for current compression parameters. */
1021 EXTERN(void) jpeg_calc_jpeg_dimensions(j_compress_ptr cinfo);
1024 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
1025 EXTERN(JDIMENSION) jpeg_write_raw_data(j_compress_ptr cinfo, JSAMPIMAGE data,
1026 JDIMENSION num_lines);
1027 EXTERN(JDIMENSION) jpeg12_write_raw_data(j_compress_ptr cinfo,
1029 JDIMENSION num_lines);
1031 /* Write a special marker. See libjpeg.txt concerning safe usage. */
1032 EXTERN(void) jpeg_write_marker(j_compress_ptr cinfo, int marker,
1033 const JOCTET *dataptr, unsigned int datalen);
1034 /* Same, but piecemeal. */
1035 EXTERN(void) jpeg_write_m_header(j_compress_ptr cinfo, int marker,
1036 unsigned int datalen);
1037 EXTERN(void) jpeg_write_m_byte(j_compress_ptr cinfo, int val);
1039 /* Alternate compression function: just write an abbreviated table file */
1040 EXTERN(void) jpeg_write_tables(j_compress_ptr cinfo);
1042 /* Write ICC profile. See libjpeg.txt for usage information. */
1043 EXTERN(void) jpeg_write_icc_profile(j_compress_ptr cinfo,
1044 const JOCTET *icc_data_ptr,
1045 unsigned int icc_data_len);
1048 /* Decompression startup: read start of JPEG datastream to see what's there */
1049 EXTERN(int) jpeg_read_header(j_decompress_ptr cinfo, boolean require_image);
1050 /* Return value is one of: */
1051 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
1052 #define JPEG_HEADER_OK 1 /* Found valid image datastream */
1053 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
1054 /* If you pass require_image = TRUE (normal case), you need not check for
1055 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
1056 * JPEG_SUSPENDED is only possible if you use a data source module that can
1057 * give a suspension return (the stdio source module doesn't).
1060 /* Main entry points for decompression */
1061 EXTERN(boolean) jpeg_start_decompress(j_decompress_ptr cinfo);
1062 EXTERN(JDIMENSION) jpeg_read_scanlines(j_decompress_ptr cinfo,
1063 JSAMPARRAY scanlines,
1064 JDIMENSION max_lines);
1065 EXTERN(JDIMENSION) jpeg12_read_scanlines(j_decompress_ptr cinfo,
1066 J12SAMPARRAY scanlines,
1067 JDIMENSION max_lines);
1068 EXTERN(JDIMENSION) jpeg16_read_scanlines(j_decompress_ptr cinfo,
1069 J16SAMPARRAY scanlines,
1070 JDIMENSION max_lines);
1071 EXTERN(JDIMENSION) jpeg_skip_scanlines(j_decompress_ptr cinfo,
1072 JDIMENSION num_lines);
1073 EXTERN(JDIMENSION) jpeg12_skip_scanlines(j_decompress_ptr cinfo,
1074 JDIMENSION num_lines);
1075 EXTERN(void) jpeg_crop_scanline(j_decompress_ptr cinfo, JDIMENSION *xoffset,
1077 EXTERN(void) jpeg12_crop_scanline(j_decompress_ptr cinfo, JDIMENSION *xoffset,
1079 EXTERN(boolean) jpeg_finish_decompress(j_decompress_ptr cinfo);
1081 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1082 EXTERN(JDIMENSION) jpeg_read_raw_data(j_decompress_ptr cinfo, JSAMPIMAGE data,
1083 JDIMENSION max_lines);
1084 EXTERN(JDIMENSION) jpeg12_read_raw_data(j_decompress_ptr cinfo,
1086 JDIMENSION max_lines);
1088 /* Additional entry points for buffered-image mode. */
1089 EXTERN(boolean) jpeg_has_multiple_scans(j_decompress_ptr cinfo);
1090 EXTERN(boolean) jpeg_start_output(j_decompress_ptr cinfo, int scan_number);
1091 EXTERN(boolean) jpeg_finish_output(j_decompress_ptr cinfo);
1092 EXTERN(boolean) jpeg_input_complete(j_decompress_ptr cinfo);
1093 EXTERN(void) jpeg_new_colormap(j_decompress_ptr cinfo);
1094 EXTERN(int) jpeg_consume_input(j_decompress_ptr cinfo);
1095 /* Return value is one of: */
1096 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1097 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1098 #define JPEG_REACHED_EOI 2 /* Reached end of image */
1099 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1100 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1102 /* Precalculate output dimensions for current decompression parameters. */
1103 #if JPEG_LIB_VERSION >= 80
1104 EXTERN(void) jpeg_core_output_dimensions(j_decompress_ptr cinfo);
1106 EXTERN(void) jpeg_calc_output_dimensions(j_decompress_ptr cinfo);
1108 /* Control saving of COM and APPn markers into marker_list. */
1109 EXTERN(void) jpeg_save_markers(j_decompress_ptr cinfo, int marker_code,
1110 unsigned int length_limit);
1112 /* Install a special processing method for COM or APPn markers. */
1113 EXTERN(void) jpeg_set_marker_processor(j_decompress_ptr cinfo,
1115 jpeg_marker_parser_method routine);
1117 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1118 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients(j_decompress_ptr cinfo);
1119 EXTERN(void) jpeg_write_coefficients(j_compress_ptr cinfo,
1120 jvirt_barray_ptr *coef_arrays);
1121 EXTERN(void) jpeg_copy_critical_parameters(j_decompress_ptr srcinfo,
1122 j_compress_ptr dstinfo);
1124 /* If you choose to abort compression or decompression before completing
1125 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1126 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1127 * if you're done with the JPEG object, but if you want to clean it up and
1128 * reuse it, call this:
1130 EXTERN(void) jpeg_abort_compress(j_compress_ptr cinfo);
1131 EXTERN(void) jpeg_abort_decompress(j_decompress_ptr cinfo);
1133 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1134 * flavor of JPEG object. These may be more convenient in some places.
1136 EXTERN(void) jpeg_abort(j_common_ptr cinfo);
1137 EXTERN(void) jpeg_destroy(j_common_ptr cinfo);
1139 /* Default restart-marker-resync procedure for use by data source modules */
1140 EXTERN(boolean) jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired);
1142 /* Read ICC profile. See libjpeg.txt for usage information. */
1143 EXTERN(boolean) jpeg_read_icc_profile(j_decompress_ptr cinfo,
1144 JOCTET **icc_data_ptr,
1145 unsigned int *icc_data_len);
1148 /* These marker codes are exported since applications and data source modules
1149 * are likely to want to use them.
1152 #define JPEG_RST0 0xD0 /* RST0 marker code */
1153 #define JPEG_EOI 0xD9 /* EOI marker code */
1154 #define JPEG_APP0 0xE0 /* APP0 marker code */
1155 #define JPEG_COM 0xFE /* COM marker code */
1158 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1159 * for structure definitions that are never filled in, keep it quiet by
1160 * supplying dummy definitions for the various substructures.
1163 #ifdef INCOMPLETE_TYPES_BROKEN
1164 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1165 struct jvirt_sarray_control { long dummy; };
1166 struct jvirt_barray_control { long dummy; };
1167 struct jpeg_comp_master { long dummy; };
1168 struct jpeg_c_main_controller { long dummy; };
1169 struct jpeg_c_prep_controller { long dummy; };
1170 struct jpeg_c_coef_controller { long dummy; };
1171 struct jpeg_marker_writer { long dummy; };
1172 struct jpeg_color_converter { long dummy; };
1173 struct jpeg_downsampler { long dummy; };
1174 struct jpeg_forward_dct { long dummy; };
1175 struct jpeg_entropy_encoder { long dummy; };
1176 struct jpeg_decomp_master { long dummy; };
1177 struct jpeg_d_main_controller { long dummy; };
1178 struct jpeg_d_coef_controller { long dummy; };
1179 struct jpeg_d_post_controller { long dummy; };
1180 struct jpeg_input_controller { long dummy; };
1181 struct jpeg_marker_reader { long dummy; };
1182 struct jpeg_entropy_decoder { long dummy; };
1183 struct jpeg_inverse_dct { long dummy; };
1184 struct jpeg_upsampler { long dummy; };
1185 struct jpeg_color_deconverter { long dummy; };
1186 struct jpeg_color_quantizer { long dummy; };
1187 #endif /* JPEG_INTERNALS */
1188 #endif /* INCOMPLETE_TYPES_BROKEN */
1192 * The JPEG library modules define JPEG_INTERNALS before including this file.
1193 * The internal structure declarations are read only when that is true.
1194 * Applications using the library should not include jpegint.h, but may wish
1195 * to include jerror.h.
1198 #ifdef JPEG_INTERNALS
1199 #include "jpegint.h" /* fetch private declarations */
1200 #include "jerror.h" /* fetch error codes too */
1204 #ifndef DONT_USE_EXTERN_C
1209 #endif /* JPEGLIB_H */