1 /*
2  * jpeglib.h
3  *
4  * Copyright (C) 1991-1998, Thomas G. Lane.
5  * Modified 2002-2019 by Guido Vollbeding.
6  * This file is part of the Independent JPEG Group's software.
7  * For conditions of distribution and use, see the accompanying README file.
8  *
9  * This file defines the application interface for the JPEG library.
10  * Most applications using the library need only include this file,
11  * and perhaps jerror.h if they want to know the exact error codes.
12  */
13 
14 #ifndef JPEGLIB_H
15 #define JPEGLIB_H
16 
17 /*
18  * First we include the configuration files that record how this
19  * installation of the JPEG library is set up.  jconfig.h can be
20  * generated automatically for many systems.  jmorecfg.h contains
21  * manual configuration options that most people need not worry about.
22  */
23 
24 #ifndef JCONFIG_INCLUDED	/* in case jinclude.h already did */
25 #include "jconfig.h"		/* widely used configuration options */
26 #endif
27 #include "jmorecfg.h"		/* seldom changed options */
28 
29 
30 #ifdef __cplusplus
31 #ifndef DONT_USE_EXTERN_C
32 extern "C" {
33 #endif
34 #endif
35 
36 /* Version IDs for the JPEG library.
37  * Might be useful for tests like "#if JPEG_LIB_VERSION >= 90".
38  */
39 
40 #define JPEG_LIB_VERSION        90	/* Compatibility version 9.0 */
41 #define JPEG_LIB_VERSION_MAJOR  9
42 #define JPEG_LIB_VERSION_MINOR  4
43 
44 
45 /* Various constants determining the sizes of things.
46  * All of these are specified by the JPEG standard,
47  * so don't change them if you want to be compatible.
48  */
49 
50 #define DCTSIZE		    8	/* The basic DCT block is 8x8 coefficients */
51 #define DCTSIZE2	    64	/* DCTSIZE squared; # of elements in a block */
52 #define NUM_QUANT_TBLS      4	/* Quantization tables are numbered 0..3 */
53 #define NUM_HUFF_TBLS       4	/* Huffman tables are numbered 0..3 */
54 #define NUM_ARITH_TBLS      16	/* Arith-coding tables are numbered 0..15 */
55 #define MAX_COMPS_IN_SCAN   4	/* JPEG limit on # of components in one scan */
56 #define MAX_SAMP_FACTOR     4	/* JPEG limit on sampling factors */
57 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
58  * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
59  * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
60  * to handle it.  We even let you do this from the jconfig.h file.  However,
61  * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
62  * sometimes emits noncompliant files doesn't mean you should too.
63  */
64 #define C_MAX_BLOCKS_IN_MCU   10 /* compressor's limit on blocks per MCU */
65 #ifndef D_MAX_BLOCKS_IN_MCU
66 #define D_MAX_BLOCKS_IN_MCU   10 /* decompressor's limit on blocks per MCU */
67 #endif
68 
69 
70 /* Data structures for images (arrays of samples and of DCT coefficients).
71  * On 80x86 machines, the image arrays are too big for near pointers,
72  * but the pointer arrays can fit in near memory.
73  */
74 
75 typedef JSAMPLE FAR *JSAMPROW;	/* ptr to one image row of pixel samples. */
76 typedef JSAMPROW *JSAMPARRAY;	/* ptr to some rows (a 2-D sample array) */
77 typedef JSAMPARRAY *JSAMPIMAGE;	/* a 3-D sample array: top index is color */
78 
79 typedef JCOEF JBLOCK[DCTSIZE2];	/* one block of coefficients */
80 typedef JBLOCK FAR *JBLOCKROW;	/* pointer to one row of coefficient blocks */
81 typedef JBLOCKROW *JBLOCKARRAY;		/* a 2-D array of coefficient blocks */
82 typedef JBLOCKARRAY *JBLOCKIMAGE;	/* a 3-D array of coefficient blocks */
83 
84 typedef JCOEF FAR *JCOEFPTR;	/* useful in a couple of places */
85 
86 
87 /* Types for JPEG compression parameters and working tables. */
88 
89 
90 /* DCT coefficient quantization tables. */
91 
92 typedef struct {
93   /* This array gives the coefficient quantizers in natural array order
94    * (not the zigzag order in which they are stored in a JPEG DQT marker).
95    * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
96    */
97   UINT16 quantval[DCTSIZE2];	/* quantization step for each coefficient */
98   /* This field is used only during compression.  It's initialized FALSE when
99    * the table is created, and set TRUE when it's been output to the file.
100    * You could suppress output of a table by setting this to TRUE.
101    * (See jpeg_suppress_tables for an example.)
102    */
103   boolean sent_table;		/* TRUE when table has been output */
104 } JQUANT_TBL;
105 
106 
107 /* Huffman coding tables. */
108 
109 typedef struct {
110   /* These two fields directly represent the contents of a JPEG DHT marker */
111   UINT8 bits[17];		/* bits[k] = # of symbols with codes of */
112 				/* length k bits; bits[0] is unused */
113   UINT8 huffval[256];		/* The symbols, in order of incr code length */
114   /* This field is used only during compression.  It's initialized FALSE when
115    * the table is created, and set TRUE when it's been output to the file.
116    * You could suppress output of a table by setting this to TRUE.
117    * (See jpeg_suppress_tables for an example.)
118    */
119   boolean sent_table;		/* TRUE when table has been output */
120 } JHUFF_TBL;
121 
122 
123 /* Basic info about one component (color channel). */
124 
125 typedef struct {
126   /* These values are fixed over the whole image. */
127   /* For compression, they must be supplied by parameter setup; */
128   /* for decompression, they are read from the SOF marker. */
129   int component_id;		/* identifier for this component (0..255) */
130   int component_index;		/* its index in SOF or cinfo->comp_info[] */
131   int h_samp_factor;		/* horizontal sampling factor (1..4) */
132   int v_samp_factor;		/* vertical sampling factor (1..4) */
133   int quant_tbl_no;		/* quantization table selector (0..3) */
134   /* These values may vary between scans. */
135   /* For compression, they must be supplied by parameter setup; */
136   /* for decompression, they are read from the SOS marker. */
137   /* The decompressor output side may not use these variables. */
138   int dc_tbl_no;		/* DC entropy table selector (0..3) */
139   int ac_tbl_no;		/* AC entropy table selector (0..3) */
140 
141   /* Remaining fields should be treated as private by applications. */
142 
143   /* These values are computed during compression or decompression startup: */
144   /* Component's size in DCT blocks.
145    * Any dummy blocks added to complete an MCU are not counted; therefore
146    * these values do not depend on whether a scan is interleaved or not.
147    */
148   JDIMENSION width_in_blocks;
149   JDIMENSION height_in_blocks;
150   /* Size of a DCT block in samples,
151    * reflecting any scaling we choose to apply during the DCT step.
152    * Values from 1 to 16 are supported.
153    * Note that different components may receive different DCT scalings.
154    */
155   int DCT_h_scaled_size;
156   int DCT_v_scaled_size;
157   /* The downsampled dimensions are the component's actual, unpadded number
158    * of samples at the main buffer (preprocessing/compression interface);
159    * DCT scaling is included, so
160    * downsampled_width =
161    *   ceil(image_width * Hi/Hmax * DCT_h_scaled_size/block_size)
162    * and similarly for height.
163    */
164   JDIMENSION downsampled_width;	 /* actual width in samples */
165   JDIMENSION downsampled_height; /* actual height in samples */
166   /* For decompression, in cases where some of the components will be
167    * ignored (eg grayscale output from YCbCr image), we can skip most
168    * computations for the unused components.
169    * For compression, some of the components will need further quantization
170    * scale by factor of 2 after DCT (eg BG_YCC output from normal RGB input).
171    * The field is first set TRUE for decompression, FALSE for compression
172    * in initial_setup, and then adapted in color conversion setup.
173    */
174   boolean component_needed;
175 
176   /* These values are computed before starting a scan of the component. */
177   /* The decompressor output side may not use these variables. */
178   int MCU_width;		/* number of blocks per MCU, horizontally */
179   int MCU_height;		/* number of blocks per MCU, vertically */
180   int MCU_blocks;		/* MCU_width * MCU_height */
181   int MCU_sample_width;	/* MCU width in samples: MCU_width * DCT_h_scaled_size */
182   int last_col_width;		/* # of non-dummy blocks across in last MCU */
183   int last_row_height;		/* # of non-dummy blocks down in last MCU */
184 
185   /* Saved quantization table for component; NULL if none yet saved.
186    * See jdinput.c comments about the need for this information.
187    * This field is currently used only for decompression.
188    */
189   JQUANT_TBL * quant_table;
190 
191   /* Private per-component storage for DCT or IDCT subsystem. */
192   void * dct_table;
193 } jpeg_component_info;
194 
195 
196 /* The script for encoding a multiple-scan file is an array of these: */
197 
198 typedef struct {
199   int comps_in_scan;		/* number of components encoded in this scan */
200   int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
201   int Ss, Se;			/* progressive JPEG spectral selection parms */
202   int Ah, Al;			/* progressive JPEG successive approx. parms */
203 } jpeg_scan_info;
204 
205 /* The decompressor can save APPn and COM markers in a list of these: */
206 
207 typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
208 
209 struct jpeg_marker_struct {
210   jpeg_saved_marker_ptr next;	/* next in list, or NULL */
211   UINT8 marker;			/* marker code: JPEG_COM, or JPEG_APP0+n */
212   unsigned int original_length;	/* # bytes of data in the file */
213   unsigned int data_length;	/* # bytes of data saved at data[] */
214   JOCTET FAR * data;		/* the data contained in the marker */
215   /* the marker length word is not counted in data_length or original_length */
216 };
217 
218 /* Known color spaces. */
219 
220 typedef enum {
221 	JCS_UNKNOWN,		/* error/unspecified */
222 	JCS_GRAYSCALE,		/* monochrome */
223 	JCS_RGB,		/* red/green/blue, standard RGB (sRGB) */
224 	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV), standard YCC */
225 	JCS_CMYK,		/* C/M/Y/K */
226 	JCS_YCCK,		/* Y/Cb/Cr/K */
227 	JCS_BG_RGB,		/* big gamut red/green/blue, bg-sRGB */
228 	JCS_BG_YCC		/* big gamut Y/Cb/Cr, bg-sYCC */
229 } J_COLOR_SPACE;
230 
231 /* Supported color transforms. */
232 
233 typedef enum {
234 	JCT_NONE           = 0,
235 	JCT_SUBTRACT_GREEN = 1
236 } J_COLOR_TRANSFORM;
237 
238 /* DCT/IDCT algorithm options. */
239 
240 typedef enum {
241 	JDCT_ISLOW,		/* slow but accurate integer algorithm */
242 	JDCT_IFAST,		/* faster, less accurate integer method */
243 	JDCT_FLOAT		/* floating-point: accurate, fast on fast HW */
244 } J_DCT_METHOD;
245 
246 #ifndef JDCT_DEFAULT		/* may be overridden in jconfig.h */
247 #define JDCT_DEFAULT  JDCT_ISLOW
248 #endif
249 #ifndef JDCT_FASTEST		/* may be overridden in jconfig.h */
250 #define JDCT_FASTEST  JDCT_IFAST
251 #endif
252 
253 /* Dithering options for decompression. */
254 
255 typedef enum {
256 	JDITHER_NONE,		/* no dithering */
257 	JDITHER_ORDERED,	/* simple ordered dither */
258 	JDITHER_FS		/* Floyd-Steinberg error diffusion dither */
259 } J_DITHER_MODE;
260 
261 
262 /* Common fields between JPEG compression and decompression master structs. */
263 
264 #define jpeg_common_fields \
265   struct jpeg_error_mgr * err;	/* Error handler module */\
266   struct jpeg_memory_mgr * mem;	/* Memory manager module */\
267   struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
268   void * client_data;		/* Available for use by application */\
269   boolean is_decompressor;	/* So common code can tell which is which */\
270   int global_state		/* For checking call sequence validity */
271 
272 /* Routines that are to be used by both halves of the library are declared
273  * to receive a pointer to this structure.  There are no actual instances of
274  * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
275  */
276 struct jpeg_common_struct {
277   jpeg_common_fields;		/* Fields common to both master struct types */
278   /* Additional fields follow in an actual jpeg_compress_struct or
279    * jpeg_decompress_struct.  All three structs must agree on these
280    * initial fields!  (This would be a lot cleaner in C++.)
281    */
282 };
283 
284 typedef struct jpeg_common_struct * j_common_ptr;
285 typedef struct jpeg_compress_struct * j_compress_ptr;
286 typedef struct jpeg_decompress_struct * j_decompress_ptr;
287 
288 
289 /* Master record for a compression instance */
290 
291 struct jpeg_compress_struct {
292   jpeg_common_fields;		/* Fields shared with jpeg_decompress_struct */
293 
294   /* Destination for compressed data */
295   struct jpeg_destination_mgr * dest;
296 
297   /* Description of source image --- these fields must be filled in by
298    * outer application before starting compression.  in_color_space must
299    * be correct before you can even call jpeg_set_defaults().
300    */
301 
302   JDIMENSION image_width;	/* input image width */
303   JDIMENSION image_height;	/* input image height */
304   int input_components;		/* # of color components in input image */
305   J_COLOR_SPACE in_color_space;	/* colorspace of input image */
306 
307   double input_gamma;		/* image gamma of input image */
308 
309   /* Compression parameters --- these fields must be set before calling
310    * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to
311    * initialize everything to reasonable defaults, then changing anything
312    * the application specifically wants to change.  That way you won't get
313    * burnt when new parameters are added.  Also note that there are several
314    * helper routines to simplify changing parameters.
315    */
316 
317   unsigned int scale_num, scale_denom; /* fraction by which to scale image */
318 
319   JDIMENSION jpeg_width;	/* scaled JPEG image width */
320   JDIMENSION jpeg_height;	/* scaled JPEG image height */
321   /* Dimensions of actual JPEG image that will be written to file,
322    * derived from input dimensions by scaling factors above.
323    * These fields are computed by jpeg_start_compress().
324    * You can also use jpeg_calc_jpeg_dimensions() to determine these values
325    * in advance of calling jpeg_start_compress().
326    */
327 
328   int data_precision;		/* bits of precision in image data */
329 
330   int num_components;		/* # of color components in JPEG image */
331   J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
332 
333   jpeg_component_info * comp_info;
334   /* comp_info[i] describes component that appears i'th in SOF */
335 
336   JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
337   int q_scale_factor[NUM_QUANT_TBLS];
338   /* ptrs to coefficient quantization tables, or NULL if not defined,
339    * and corresponding scale factors (percentage, initialized 100).
340    */
341 
342   JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
343   JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
344   /* ptrs to Huffman coding tables, or NULL if not defined */
345 
346   UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
347   UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
348   UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
349 
350   int num_scans;		/* # of entries in scan_info array */
351   const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
352   /* The default value of scan_info is NULL, which causes a single-scan
353    * sequential JPEG file to be emitted.  To create a multi-scan file,
354    * set num_scans and scan_info to point to an array of scan definitions.
355    */
356 
357   boolean raw_data_in;		/* TRUE=caller supplies downsampled data */
358   boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
359   boolean optimize_coding;	/* TRUE=optimize entropy encoding parms */
360   boolean CCIR601_sampling;	/* TRUE=first samples are cosited */
361   boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
362   int smoothing_factor;		/* 1..100, or 0 for no input smoothing */
363   J_DCT_METHOD dct_method;	/* DCT algorithm selector */
364 
365   /* The restart interval can be specified in absolute MCUs by setting
366    * restart_interval, or in MCU rows by setting restart_in_rows
367    * (in which case the correct restart_interval will be figured
368    * for each scan).
369    */
370   unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
371   int restart_in_rows;		/* if > 0, MCU rows per restart interval */
372 
373   /* Parameters controlling emission of special markers. */
374 
375   boolean write_JFIF_header;	/* should a JFIF marker be written? */
376   UINT8 JFIF_major_version;	/* What to write for the JFIF version number */
377   UINT8 JFIF_minor_version;
378   /* These three values are not used by the JPEG code, merely copied */
379   /* into the JFIF APP0 marker.  density_unit can be 0 for unknown, */
380   /* 1 for dots/inch, or 2 for dots/cm.  Note that the pixel aspect */
381   /* ratio is defined by X_density/Y_density even when density_unit=0. */
382   UINT8 density_unit;		/* JFIF code for pixel size units */
383   UINT16 X_density;		/* Horizontal pixel density */
384   UINT16 Y_density;		/* Vertical pixel density */
385   boolean write_Adobe_marker;	/* should an Adobe marker be written? */
386 
387   J_COLOR_TRANSFORM color_transform;
388   /* Color transform identifier, writes LSE marker if nonzero */
389 
390   /* State variable: index of next scanline to be written to
391    * jpeg_write_scanlines().  Application may use this to control its
392    * processing loop, e.g., "while (next_scanline < image_height)".
393    */
394 
395   JDIMENSION next_scanline;	/* 0 .. image_height-1  */
396 
397   /* Remaining fields are known throughout compressor, but generally
398    * should not be touched by a surrounding application.
399    */
400 
401   /*
402    * These fields are computed during compression startup
403    */
404   boolean progressive_mode;	/* TRUE if scan script uses progressive mode */
405   int max_h_samp_factor;	/* largest h_samp_factor */
406   int max_v_samp_factor;	/* largest v_samp_factor */
407 
408   int min_DCT_h_scaled_size;	/* smallest DCT_h_scaled_size of any component */
409   int min_DCT_v_scaled_size;	/* smallest DCT_v_scaled_size of any component */
410 
411   JDIMENSION total_iMCU_rows;	/* # of iMCU rows to be input to coef ctlr */
412   /* The coefficient controller receives data in units of MCU rows as defined
413    * for fully interleaved scans (whether the JPEG file is interleaved or not).
414    * There are v_samp_factor * DCT_v_scaled_size sample rows of each component
415    * in an "iMCU" (interleaved MCU) row.
416    */
417 
418   /*
419    * These fields are valid during any one scan.
420    * They describe the components and MCUs actually appearing in the scan.
421    */
422   int comps_in_scan;		/* # of JPEG components in this scan */
423   jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
424   /* *cur_comp_info[i] describes component that appears i'th in SOS */
425 
426   JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
427   JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */
428 
429   int blocks_in_MCU;		/* # of DCT blocks per MCU */
430   int MCU_membership[C_MAX_BLOCKS_IN_MCU];
431   /* MCU_membership[i] is index in cur_comp_info of component owning */
432   /* i'th block in an MCU */
433 
434   int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */
435 
436   int block_size;		/* the basic DCT block size: 1..16 */
437   const int * natural_order;	/* natural-order position array */
438   int lim_Se;			/* min( Se, DCTSIZE2-1 ) */
439 
440   /*
441    * Links to compression subobjects (methods and private variables of modules)
442    */
443   struct jpeg_comp_master * master;
444   struct jpeg_c_main_controller * main;
445   struct jpeg_c_prep_controller * prep;
446   struct jpeg_c_coef_controller * coef;
447   struct jpeg_marker_writer * marker;
448   struct jpeg_color_converter * cconvert;
449   struct jpeg_downsampler * downsample;
450   struct jpeg_forward_dct * fdct;
451   struct jpeg_entropy_encoder * entropy;
452   jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
453   int script_space_size;
454 };
455 
456 
457 /* Master record for a decompression instance */
458 
459 struct jpeg_decompress_struct {
460   jpeg_common_fields;		/* Fields shared with jpeg_compress_struct */
461 
462   /* Source of compressed data */
463   struct jpeg_source_mgr * src;
464 
465   /* Basic description of image --- filled in by jpeg_read_header(). */
466   /* Application may inspect these values to decide how to process image. */
467 
468   JDIMENSION image_width;	/* nominal image width (from SOF marker) */
469   JDIMENSION image_height;	/* nominal image height */
470   int num_components;		/* # of color components in JPEG image */
471   J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
472 
473   /* Decompression processing parameters --- these fields must be set before
474    * calling jpeg_start_decompress().  Note that jpeg_read_header() initializes
475    * them to default values.
476    */
477 
478   J_COLOR_SPACE out_color_space; /* colorspace for output */
479 
480   unsigned int scale_num, scale_denom; /* fraction by which to scale image */
481 
482   double output_gamma;		/* image gamma wanted in output */
483 
484   boolean buffered_image;	/* TRUE=multiple output passes */
485   boolean raw_data_out;		/* TRUE=downsampled data wanted */
486 
487   J_DCT_METHOD dct_method;	/* IDCT algorithm selector */
488   boolean do_fancy_upsampling;	/* TRUE=apply fancy upsampling */
489   boolean do_block_smoothing;	/* TRUE=apply interblock smoothing */
490 
491   boolean quantize_colors;	/* TRUE=colormapped output wanted */
492   /* the following are ignored if not quantize_colors: */
493   J_DITHER_MODE dither_mode;	/* type of color dithering to use */
494   boolean two_pass_quantize;	/* TRUE=use two-pass color quantization */
495   int desired_number_of_colors;	/* max # colors to use in created colormap */
496   /* these are significant only in buffered-image mode: */
497   boolean enable_1pass_quant;	/* enable future use of 1-pass quantizer */
498   boolean enable_external_quant;/* enable future use of external colormap */
499   boolean enable_2pass_quant;	/* enable future use of 2-pass quantizer */
500 
501   /* Description of actual output image that will be returned to application.
502    * These fields are computed by jpeg_start_decompress().
503    * You can also use jpeg_calc_output_dimensions() to determine these values
504    * in advance of calling jpeg_start_decompress().
505    */
506 
507   JDIMENSION output_width;	/* scaled image width */
508   JDIMENSION output_height;	/* scaled image height */
509   int out_color_components;	/* # of color components in out_color_space */
510   int output_components;	/* # of color components returned */
511   /* output_components is 1 (a colormap index) when quantizing colors;
512    * otherwise it equals out_color_components.
513    */
514   int rec_outbuf_height;	/* min recommended height of scanline buffer */
515   /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
516    * high, space and time will be wasted due to unnecessary data copying.
517    * Usually rec_outbuf_height will be 1 or 2, at most 4.
518    */
519 
520   /* When quantizing colors, the output colormap is described by these fields.
521    * The application can supply a colormap by setting colormap non-NULL before
522    * calling jpeg_start_decompress; otherwise a colormap is created during
523    * jpeg_start_decompress or jpeg_start_output.
524    * The map has out_color_components rows and actual_number_of_colors columns.
525    */
526   int actual_number_of_colors;	/* number of entries in use */
527   JSAMPARRAY colormap;		/* The color map as a 2-D pixel array */
528 
529   /* State variables: these variables indicate the progress of decompression.
530    * The application may examine these but must not modify them.
531    */
532 
533   /* Row index of next scanline to be read from jpeg_read_scanlines().
534    * Application may use this to control its processing loop, e.g.,
535    * "while (output_scanline < output_height)".
536    */
537   JDIMENSION output_scanline;	/* 0 .. output_height-1  */
538 
539   /* Current input scan number and number of iMCU rows completed in scan.
540    * These indicate the progress of the decompressor input side.
541    */
542   int input_scan_number;	/* Number of SOS markers seen so far */
543   JDIMENSION input_iMCU_row;	/* Number of iMCU rows completed */
544 
545   /* The "output scan number" is the notional scan being displayed by the
546    * output side.  The decompressor will not allow output scan/row number
547    * to get ahead of input scan/row, but it can fall arbitrarily far behind.
548    */
549   int output_scan_number;	/* Nominal scan number being displayed */
550   JDIMENSION output_iMCU_row;	/* Number of iMCU rows read */
551 
552   /* Current progression status.  coef_bits[c][i] indicates the precision
553    * with which component c's DCT coefficient i (in zigzag order) is known.
554    * It is -1 when no data has yet been received, otherwise it is the point
555    * transform (shift) value for the most recent scan of the coefficient
556    * (thus, 0 at completion of the progression).
557    * This pointer is NULL when reading a non-progressive file.
558    */
559   int (*coef_bits)[DCTSIZE2];	/* -1 or current Al value for each coef */
560 
561   /* Internal JPEG parameters --- the application usually need not look at
562    * these fields.  Note that the decompressor output side may not use
563    * any parameters that can change between scans.
564    */
565 
566   /* Quantization and Huffman tables are carried forward across input
567    * datastreams when processing abbreviated JPEG datastreams.
568    */
569 
570   JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
571   /* ptrs to coefficient quantization tables, or NULL if not defined */
572 
573   JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
574   JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
575   /* ptrs to Huffman coding tables, or NULL if not defined */
576 
577   /* These parameters are never carried across datastreams, since they
578    * are given in SOF/SOS markers or defined to be reset by SOI.
579    */
580 
581   int data_precision;		/* bits of precision in image data */
582 
583   jpeg_component_info * comp_info;
584   /* comp_info[i] describes component that appears i'th in SOF */
585 
586   boolean is_baseline;		/* TRUE if Baseline SOF0 encountered */
587   boolean progressive_mode;	/* TRUE if SOFn specifies progressive mode */
588   boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
589 
590   UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
591   UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
592   UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
593 
594   unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
595 
596   /* These fields record data obtained from optional markers recognized by
597    * the JPEG library.
598    */
599   boolean saw_JFIF_marker;	/* TRUE iff a JFIF APP0 marker was found */
600   /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
601   UINT8 JFIF_major_version;	/* JFIF version number */
602   UINT8 JFIF_minor_version;
603   UINT8 density_unit;		/* JFIF code for pixel size units */
604   UINT16 X_density;		/* Horizontal pixel density */
605   UINT16 Y_density;		/* Vertical pixel density */
606   boolean saw_Adobe_marker;	/* TRUE iff an Adobe APP14 marker was found */
607   UINT8 Adobe_transform;	/* Color transform code from Adobe marker */
608 
609   J_COLOR_TRANSFORM color_transform;
610   /* Color transform identifier derived from LSE marker, otherwise zero */
611 
612   boolean CCIR601_sampling;	/* TRUE=first samples are cosited */
613 
614   /* Aside from the specific data retained from APPn markers known to the
615    * library, the uninterpreted contents of any or all APPn and COM markers
616    * can be saved in a list for examination by the application.
617    */
618   jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
619 
620   /* Remaining fields are known throughout decompressor, but generally
621    * should not be touched by a surrounding application.
622    */
623 
624   /*
625    * These fields are computed during decompression startup
626    */
627   int max_h_samp_factor;	/* largest h_samp_factor */
628   int max_v_samp_factor;	/* largest v_samp_factor */
629 
630   int min_DCT_h_scaled_size;	/* smallest DCT_h_scaled_size of any component */
631   int min_DCT_v_scaled_size;	/* smallest DCT_v_scaled_size of any component */
632 
633   JDIMENSION total_iMCU_rows;	/* # of iMCU rows in image */
634   /* The coefficient controller's input and output progress is measured in
635    * units of "iMCU" (interleaved MCU) rows.  These are the same as MCU rows
636    * in fully interleaved JPEG scans, but are used whether the scan is
637    * interleaved or not.  We define an iMCU row as v_samp_factor DCT block
638    * rows of each component.  Therefore, the IDCT output contains
639    * v_samp_factor * DCT_v_scaled_size sample rows of a component per iMCU row.
640    */
641 
642   JSAMPLE * sample_range_limit; /* table for fast range-limiting */
643 
644   /*
645    * These fields are valid during any one scan.
646    * They describe the components and MCUs actually appearing in the scan.
647    * Note that the decompressor output side must not use these fields.
648    */
649   int comps_in_scan;		/* # of JPEG components in this scan */
650   jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
651   /* *cur_comp_info[i] describes component that appears i'th in SOS */
652 
653   JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
654   JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */
655 
656   int blocks_in_MCU;		/* # of DCT blocks per MCU */
657   int MCU_membership[D_MAX_BLOCKS_IN_MCU];
658   /* MCU_membership[i] is index in cur_comp_info of component owning */
659   /* i'th block in an MCU */
660 
661   int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */
662 
663   /* These fields are derived from Se of first SOS marker.
664    */
665   int block_size;		/* the basic DCT block size: 1..16 */
666   const int * natural_order; /* natural-order position array for entropy decode */
667   int lim_Se;			/* min( Se, DCTSIZE2-1 ) for entropy decode */
668 
669   /* This field is shared between entropy decoder and marker parser.
670    * It is either zero or the code of a JPEG marker that has been
671    * read from the data source, but has not yet been processed.
672    */
673   int unread_marker;
674 
675   /*
676    * Links to decompression subobjects (methods, private variables of modules)
677    */
678   struct jpeg_decomp_master * master;
679   struct jpeg_d_main_controller * main;
680   struct jpeg_d_coef_controller * coef;
681   struct jpeg_d_post_controller * post;
682   struct jpeg_input_controller * inputctl;
683   struct jpeg_marker_reader * marker;
684   struct jpeg_entropy_decoder * entropy;
685   struct jpeg_inverse_dct * idct;
686   struct jpeg_upsampler * upsample;
687   struct jpeg_color_deconverter * cconvert;
688   struct jpeg_color_quantizer * cquantize;
689 };
690 
691 
692 /* "Object" declarations for JPEG modules that may be supplied or called
693  * directly by the surrounding application.
694  * As with all objects in the JPEG library, these structs only define the
695  * publicly visible methods and state variables of a module.  Additional
696  * private fields may exist after the public ones.
697  */
698 
699 
700 /* Error handler object */
701 
702 struct jpeg_error_mgr {
703   /* Error exit handler: does not return to caller */
704   JMETHOD(noreturn_t, error_exit, (j_common_ptr cinfo));
705   /* Conditionally emit a trace or warning message */
706   JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
707   /* Routine that actually outputs a trace or error message */
708   JMETHOD(void, output_message, (j_common_ptr cinfo));
709   /* Format a message string for the most recent JPEG error or message */
710   JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
711 #define JMSG_LENGTH_MAX  200	/* recommended size of format_message buffer */
712   /* Reset error state variables at start of a new image */
713   JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
714 
715   /* The message ID code and any parameters are saved here.
716    * A message can have one string parameter or up to 8 int parameters.
717    */
718   int msg_code;
719 #define JMSG_STR_PARM_MAX  80
720   union {
721     int i[8];
722     char s[JMSG_STR_PARM_MAX];
723   } msg_parm;
724 
725   /* Standard state variables for error facility */
726 
727   int trace_level;		/* max msg_level that will be displayed */
728 
729   /* For recoverable corrupt-data errors, we emit a warning message,
730    * but keep going unless emit_message chooses to abort.  emit_message
731    * should count warnings in num_warnings.  The surrounding application
732    * can check for bad data by seeing if num_warnings is nonzero at the
733    * end of processing.
734    */
735   long num_warnings;		/* number of corrupt-data warnings */
736 
737   /* These fields point to the table(s) of error message strings.
738    * An application can change the table pointer to switch to a different
739    * message list (typically, to change the language in which errors are
740    * reported).  Some applications may wish to add additional error codes
741    * that will be handled by the JPEG library error mechanism; the second
742    * table pointer is used for this purpose.
743    *
744    * First table includes all errors generated by JPEG library itself.
745    * Error code 0 is reserved for a "no such error string" message.
746    */
747   const char * const * jpeg_message_table; /* Library errors */
748   int last_jpeg_message;    /* Table contains strings 0..last_jpeg_message */
749   /* Second table can be added by application (see cjpeg/djpeg for example).
750    * It contains strings numbered first_addon_message..last_addon_message.
751    */
752   const char * const * addon_message_table; /* Non-library errors */
753   int first_addon_message;	/* code for first string in addon table */
754   int last_addon_message;	/* code for last string in addon table */
755 };
756 
757 
758 /* Progress monitor object */
759 
760 struct jpeg_progress_mgr {
761   JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
762 
763   long pass_counter;		/* work units completed in this pass */
764   long pass_limit;		/* total number of work units in this pass */
765   int completed_passes;		/* passes completed so far */
766   int total_passes;		/* total number of passes expected */
767 };
768 
769 
770 /* Data destination object for compression */
771 
772 struct jpeg_destination_mgr {
773   JOCTET * next_output_byte;	/* => next byte to write in buffer */
774   size_t free_in_buffer;	/* # of byte spaces remaining in buffer */
775 
776   JMETHOD(void, init_destination, (j_compress_ptr cinfo));
777   JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
778   JMETHOD(void, term_destination, (j_compress_ptr cinfo));
779 };
780 
781 
782 /* Data source object for decompression */
783 
784 struct jpeg_source_mgr {
785   const JOCTET * next_input_byte; /* => next byte to read from buffer */
786   size_t bytes_in_buffer;	/* # of bytes remaining in buffer */
787 
788   JMETHOD(void, init_source, (j_decompress_ptr cinfo));
789   JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
790   JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
791   JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
792   JMETHOD(void, term_source, (j_decompress_ptr cinfo));
793 };
794 
795 
796 /* Memory manager object.
797  * Allocates "small" objects (a few K total), "large" objects (tens of K),
798  * and "really big" objects (virtual arrays with backing store if needed).
799  * The memory manager does not allow individual objects to be freed; rather,
800  * each created object is assigned to a pool, and whole pools can be freed
801  * at once.  This is faster and more convenient than remembering exactly what
802  * to free, especially where malloc()/free() are not too speedy.
803  * NB: alloc routines never return NULL.  They exit to error_exit if not
804  * successful.
805  */
806 
807 #define JPOOL_PERMANENT	0	/* lasts until master record is destroyed */
808 #define JPOOL_IMAGE	1	/* lasts until done with image/datastream */
809 #define JPOOL_NUMPOOLS	2
810 
811 typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
812 typedef struct jvirt_barray_control * jvirt_barray_ptr;
813 
814 
815 struct jpeg_memory_mgr {
816   /* Method pointers */
817   JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
818 				size_t sizeofobject));
819   JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
820 				     size_t sizeofobject));
821   JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
822 				     JDIMENSION samplesperrow,
823 				     JDIMENSION numrows));
824   JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
825 				      JDIMENSION blocksperrow,
826 				      JDIMENSION numrows));
827   JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
828 						  int pool_id,
829 						  boolean pre_zero,
830 						  JDIMENSION samplesperrow,
831 						  JDIMENSION numrows,
832 						  JDIMENSION maxaccess));
833   JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
834 						  int pool_id,
835 						  boolean pre_zero,
836 						  JDIMENSION blocksperrow,
837 						  JDIMENSION numrows,
838 						  JDIMENSION maxaccess));
839   JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
840   JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
841 					   jvirt_sarray_ptr ptr,
842 					   JDIMENSION start_row,
843 					   JDIMENSION num_rows,
844 					   boolean writable));
845   JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
846 					    jvirt_barray_ptr ptr,
847 					    JDIMENSION start_row,
848 					    JDIMENSION num_rows,
849 					    boolean writable));
850   JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
851   JMETHOD(void, self_destruct, (j_common_ptr cinfo));
852 
853   /* Limit on memory allocation for this JPEG object.  (Note that this is
854    * merely advisory, not a guaranteed maximum; it only affects the space
855    * used for virtual-array buffers.)  May be changed by outer application
856    * after creating the JPEG object.
857    */
858   long max_memory_to_use;
859 
860   /* Maximum allocation request accepted by alloc_large. */
861   long max_alloc_chunk;
862 };
863 
864 
865 /* Routine signature for application-supplied marker processing methods.
866  * Need not pass marker code since it is stored in cinfo->unread_marker.
867  */
868 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
869 
870 
871 /* Declarations for routines called by application.
872  * The JPP macro hides prototype parameters from compilers that can't cope.
873  * Note JPP requires double parentheses.
874  */
875 
876 #ifdef HAVE_PROTOTYPES
877 #define JPP(arglist)	arglist
878 #else
879 #define JPP(arglist)	()
880 #endif
881 
882 
883 /* Short forms of external names for systems with brain-damaged linkers.
884  * We shorten external names to be unique in the first six letters, which
885  * is good enough for all known systems.
886  * (If your compiler itself needs names to be unique in less than 15
887  * characters, you are out of luck.  Get a better compiler.)
888  */
889 
890 #ifdef NEED_SHORT_EXTERNAL_NAMES
891 #define jpeg_std_error		jStdError
892 #define jpeg_CreateCompress	jCreaCompress
893 #define jpeg_CreateDecompress	jCreaDecompress
894 #define jpeg_destroy_compress	jDestCompress
895 #define jpeg_destroy_decompress	jDestDecompress
896 #define jpeg_stdio_dest		jStdDest
897 #define jpeg_stdio_src		jStdSrc
898 #define jpeg_mem_dest		jMemDest
899 #define jpeg_mem_src		jMemSrc
900 #define jpeg_set_defaults	jSetDefaults
901 #define jpeg_set_colorspace	jSetColorspace
902 #define jpeg_default_colorspace	jDefColorspace
903 #define jpeg_set_quality	jSetQuality
904 #define jpeg_set_linear_quality	jSetLQuality
905 #define jpeg_default_qtables	jDefQTables
906 #define jpeg_add_quant_table	jAddQuantTable
907 #define jpeg_quality_scaling	jQualityScaling
908 #define jpeg_simple_progression	jSimProgress
909 #define jpeg_suppress_tables	jSuppressTables
910 #define jpeg_alloc_quant_table	jAlcQTable
911 #define jpeg_alloc_huff_table	jAlcHTable
912 #define jpeg_std_huff_table	jStdHTable
913 #define jpeg_start_compress	jStrtCompress
914 #define jpeg_write_scanlines	jWrtScanlines
915 #define jpeg_finish_compress	jFinCompress
916 #define jpeg_calc_jpeg_dimensions	jCjpegDimensions
917 #define jpeg_write_raw_data	jWrtRawData
918 #define jpeg_write_marker	jWrtMarker
919 #define jpeg_write_m_header	jWrtMHeader
920 #define jpeg_write_m_byte	jWrtMByte
921 #define jpeg_write_tables	jWrtTables
922 #define jpeg_read_header	jReadHeader
923 #define jpeg_start_decompress	jStrtDecompress
924 #define jpeg_read_scanlines	jReadScanlines
925 #define jpeg_finish_decompress	jFinDecompress
926 #define jpeg_read_raw_data	jReadRawData
927 #define jpeg_has_multiple_scans	jHasMultScn
928 #define jpeg_start_output	jStrtOutput
929 #define jpeg_finish_output	jFinOutput
930 #define jpeg_input_complete	jInComplete
931 #define jpeg_new_colormap	jNewCMap
932 #define jpeg_consume_input	jConsumeInput
933 #define jpeg_core_output_dimensions	jCoreDimensions
934 #define jpeg_calc_output_dimensions	jCalcDimensions
935 #define jpeg_save_markers	jSaveMarkers
936 #define jpeg_set_marker_processor	jSetMarker
937 #define jpeg_read_coefficients	jReadCoefs
938 #define jpeg_write_coefficients	jWrtCoefs
939 #define jpeg_copy_critical_parameters	jCopyCrit
940 #define jpeg_abort_compress	jAbrtCompress
941 #define jpeg_abort_decompress	jAbrtDecompress
942 #define jpeg_abort		jAbort
943 #define jpeg_destroy		jDestroy
944 #define jpeg_resync_to_restart	jResyncRestart
945 #endif /* NEED_SHORT_EXTERNAL_NAMES */
946 
947 
948 /* Default error-management setup */
949 EXTERN(struct jpeg_error_mgr *) jpeg_std_error
950 	JPP((struct jpeg_error_mgr * err));
951 
952 /* Initialization of JPEG compression objects.
953  * jpeg_create_compress() and jpeg_create_decompress() are the exported
954  * names that applications should call.  These expand to calls on
955  * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
956  * passed for version mismatch checking.
957  * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
958  */
959 #define jpeg_create_compress(cinfo) \
960     jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
961 			(size_t) sizeof(struct jpeg_compress_struct))
962 #define jpeg_create_decompress(cinfo) \
963     jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
964 			  (size_t) sizeof(struct jpeg_decompress_struct))
965 EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
966 				      int version, size_t structsize));
967 EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
968 					int version, size_t structsize));
969 /* Destruction of JPEG compression objects */
970 EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
971 EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
972 
973 /* Standard data source and destination managers: stdio streams. */
974 /* Caller is responsible for opening the file before and closing after. */
975 EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
976 EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
977 
978 /* Data source and destination managers: memory buffers. */
979 EXTERN(void) jpeg_mem_dest JPP((j_compress_ptr cinfo,
980 			       unsigned char ** outbuffer,
981 			       size_t * outsize));
982 EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo,
983 			      const unsigned char * inbuffer,
984 			      size_t insize));
985 
986 /* Default parameter setup for compression */
987 EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
988 /* Compression parameter setup aids */
989 EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
990 				      J_COLOR_SPACE colorspace));
991 EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
992 EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
993 				   boolean force_baseline));
994 EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
995 					  int scale_factor,
996 					  boolean force_baseline));
997 EXTERN(void) jpeg_default_qtables JPP((j_compress_ptr cinfo,
998 				       boolean force_baseline));
999 EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
1000 				       const unsigned int *basic_table,
1001 				       int scale_factor,
1002 				       boolean force_baseline));
1003 EXTERN(int) jpeg_quality_scaling JPP((int quality));
1004 EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
1005 EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
1006 				       boolean suppress));
1007 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
1008 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
1009 EXTERN(JHUFF_TBL *) jpeg_std_huff_table JPP((j_common_ptr cinfo,
1010 					     boolean isDC, int tblno));
1011 
1012 /* Main entry points for compression */
1013 EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
1014 				      boolean write_all_tables));
1015 EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
1016 					     JSAMPARRAY scanlines,
1017 					     JDIMENSION num_lines));
1018 EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
1019 
1020 /* Precalculate JPEG dimensions for current compression parameters. */
1021 EXTERN(void) jpeg_calc_jpeg_dimensions JPP((j_compress_ptr cinfo));
1022 
1023 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
1024 EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
1025 					    JSAMPIMAGE data,
1026 					    JDIMENSION num_lines));
1027 
1028 /* Write a special marker.  See libjpeg.txt concerning safe usage. */
1029 EXTERN(void) jpeg_write_marker
1030 	JPP((j_compress_ptr cinfo, int marker,
1031 	     const JOCTET * dataptr, unsigned int datalen));
1032 /* Same, but piecemeal. */
1033 EXTERN(void) jpeg_write_m_header
1034 	JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
1035 EXTERN(void) jpeg_write_m_byte
1036 	JPP((j_compress_ptr cinfo, int val));
1037 
1038 /* Alternate compression function: just write an abbreviated table file */
1039 EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
1040 
1041 /* Decompression startup: read start of JPEG datastream to see what's there */
1042 EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
1043 				  boolean require_image));
1044 /* Return value is one of: */
1045 #define JPEG_SUSPENDED		0 /* Suspended due to lack of input data */
1046 #define JPEG_HEADER_OK		1 /* Found valid image datastream */
1047 #define JPEG_HEADER_TABLES_ONLY	2 /* Found valid table-specs-only datastream */
1048 /* If you pass require_image = TRUE (normal case), you need not check for
1049  * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
1050  * JPEG_SUSPENDED is only possible if you use a data source module that can
1051  * give a suspension return (the stdio source module doesn't).
1052  */
1053 
1054 /* Main entry points for decompression */
1055 EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
1056 EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
1057 					    JSAMPARRAY scanlines,
1058 					    JDIMENSION max_lines));
1059 EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
1060 
1061 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1062 EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
1063 					   JSAMPIMAGE data,
1064 					   JDIMENSION max_lines));
1065 
1066 /* Additional entry points for buffered-image mode. */
1067 EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
1068 EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
1069 				       int scan_number));
1070 EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
1071 EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
1072 EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1073 EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
1074 /* Return value is one of: */
1075 /* #define JPEG_SUSPENDED	0    Suspended due to lack of input data */
1076 #define JPEG_REACHED_SOS	1 /* Reached start of new scan */
1077 #define JPEG_REACHED_EOI	2 /* Reached end of image */
1078 #define JPEG_ROW_COMPLETED	3 /* Completed one iMCU row */
1079 #define JPEG_SCAN_COMPLETED	4 /* Completed last iMCU row of a scan */
1080 
1081 /* Precalculate output dimensions for current decompression parameters. */
1082 EXTERN(void) jpeg_core_output_dimensions JPP((j_decompress_ptr cinfo));
1083 EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1084 
1085 /* Control saving of COM and APPn markers into marker_list. */
1086 EXTERN(void) jpeg_save_markers
1087 	JPP((j_decompress_ptr cinfo, int marker_code,
1088 	     unsigned int length_limit));
1089 
1090 /* Install a special processing method for COM or APPn markers. */
1091 EXTERN(void) jpeg_set_marker_processor
1092 	JPP((j_decompress_ptr cinfo, int marker_code,
1093 	     jpeg_marker_parser_method routine));
1094 
1095 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1096 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1097 EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1098 					  jvirt_barray_ptr * coef_arrays));
1099 EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1100 						j_compress_ptr dstinfo));
1101 
1102 /* If you choose to abort compression or decompression before completing
1103  * jpeg_finish_(de)compress, then you need to clean up to release memory,
1104  * temporary files, etc.  You can just call jpeg_destroy_(de)compress
1105  * if you're done with the JPEG object, but if you want to clean it up and
1106  * reuse it, call this:
1107  */
1108 EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
1109 EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1110 
1111 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1112  * flavor of JPEG object.  These may be more convenient in some places.
1113  */
1114 EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
1115 EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
1116 
1117 /* Default restart-marker-resync procedure for use by data source modules */
1118 EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1119 					    int desired));
1120 
1121 
1122 /* These marker codes are exported since applications and data source modules
1123  * are likely to want to use them.
1124  */
1125 
1126 #define JPEG_RST0	0xD0	/* RST0 marker code */
1127 #define JPEG_EOI	0xD9	/* EOI marker code */
1128 #define JPEG_APP0	0xE0	/* APP0 marker code */
1129 #define JPEG_COM	0xFE	/* COM marker code */
1130 
1131 
1132 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1133  * for structure definitions that are never filled in, keep it quiet by
1134  * supplying dummy definitions for the various substructures.
1135  */
1136 
1137 #ifdef INCOMPLETE_TYPES_BROKEN
1138 #ifndef JPEG_INTERNALS		/* will be defined in jpegint.h */
1139 struct jvirt_sarray_control { long dummy; };
1140 struct jvirt_barray_control { long dummy; };
1141 struct jpeg_comp_master { long dummy; };
1142 struct jpeg_c_main_controller { long dummy; };
1143 struct jpeg_c_prep_controller { long dummy; };
1144 struct jpeg_c_coef_controller { long dummy; };
1145 struct jpeg_marker_writer { long dummy; };
1146 struct jpeg_color_converter { long dummy; };
1147 struct jpeg_downsampler { long dummy; };
1148 struct jpeg_forward_dct { long dummy; };
1149 struct jpeg_entropy_encoder { long dummy; };
1150 struct jpeg_decomp_master { long dummy; };
1151 struct jpeg_d_main_controller { long dummy; };
1152 struct jpeg_d_coef_controller { long dummy; };
1153 struct jpeg_d_post_controller { long dummy; };
1154 struct jpeg_input_controller { long dummy; };
1155 struct jpeg_marker_reader { long dummy; };
1156 struct jpeg_entropy_decoder { long dummy; };
1157 struct jpeg_inverse_dct { long dummy; };
1158 struct jpeg_upsampler { long dummy; };
1159 struct jpeg_color_deconverter { long dummy; };
1160 struct jpeg_color_quantizer { long dummy; };
1161 #endif /* JPEG_INTERNALS */
1162 #endif /* INCOMPLETE_TYPES_BROKEN */
1163 
1164 
1165 /*
1166  * The JPEG library modules define JPEG_INTERNALS before including this file.
1167  * The internal structure declarations are read only when that is true.
1168  * Applications using the library should not include jpegint.h, but may wish
1169  * to include jerror.h.
1170  */
1171 
1172 #ifdef JPEG_INTERNALS
1173 #include "jpegint.h"		/* fetch private declarations */
1174 #include "jerror.h"		/* fetch error codes too */
1175 #endif
1176 
1177 #ifdef __cplusplus
1178 #ifndef DONT_USE_EXTERN_C
1179 }
1180 #endif
1181 #endif
1182 
1183 #endif /* JPEGLIB_H */
1184