1 module libjpeg.jpeglib;
2 /*
3  * jpeglib.h
4  *
5  * This file was part of the Independent JPEG Group's software:
6  * Copyright (C) 1991-1998, Thomas G. Lane.
7  * Modified 2002-2009 by Guido Vollbeding.
8  * Modifications:
9  * Copyright (C) 2009-2011, 2013, D. R. Commander.
10  * For conditions of distribution and use, see the accompanying README file.
11  *
12  * This file defines the application interface for the JPEG library.
13  * Most applications using the library need only include this file,
14  * and perhaps jerror.h if they want to know the exact error codes.
15  */
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 import libjpeg.jconfig;		/* widely used configuration options */
25 import libjpeg.jmorecfg;	/* seldom changed options */
26 
27 public:
28 extern (C):
29 
30 /* Various constants determining the sizes of things.
31  * All of these are specified by the JPEG standard, so don't change them
32  * if you want to be compatible.
33  */
34 
35 enum DCTSIZE             = 8;	/* The basic DCT block is 8x8 samples */
36 enum DCTSIZE2            = 64;	/* DCTSIZE squared; # of elements in a block */
37 enum NUM_QUANT_TBLS      = 4;	/* Quantization tables are numbered 0..3 */
38 enum NUM_HUFF_TBLS       = 4;	/* Huffman tables are numbered 0..3 */
39 enum NUM_ARITH_TBLS      = 16;	/* Arith-coding tables are numbered 0..15 */
40 enum MAX_COMPS_IN_SCAN   = 4;	/* JPEG limit on # of components in one scan */
41 enum MAX_SAMP_FACTOR     = 4;	/* JPEG limit on sampling factors */
42 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
43  * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
44  * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
45  * to handle it.  We even let you do this from the jconfig.h file.  However,
46  * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
47  * sometimes emits noncompliant files doesn't mean you should too.
48  */
49 enum C_MAX_BLOCKS_IN_MCU   = 10; /* compressor's limit on blocks per MCU */
50 enum D_MAX_BLOCKS_IN_MCU   = 10; /* decompressor's limit on blocks per MCU */
51 
52 
53 /* Data structures for images (arrays of samples and of DCT coefficients).
54  * On 80x86 machines, the image arrays are too big for near pointers,
55  * but the pointer arrays can fit in near memory.
56  */
57 
58 alias JSAMPLE     *JSAMPROW;	/* ptr to one image row of pixel samples. */
59 alias JSAMPROW *JSAMPARRAY;	/* ptr to some rows (a 2-D sample array) */
60 alias JSAMPARRAY *JSAMPIMAGE;	/* a 3-D sample array: top index is color */
61 
62 alias JCOEF JBLOCK[DCTSIZE2];	/* one block of coefficients */
63 alias JBLOCK     *JBLOCKROW;	/* pointer to one row of coefficient blocks */
64 alias JBLOCKROW *JBLOCKARRAY;		/* a 2-D array of coefficient blocks */
65 alias JBLOCKARRAY *JBLOCKIMAGE;	/* a 3-D array of coefficient blocks */
66 
67 alias JCOEF     *JCOEFPTR;	/* useful in a couple of places */
68 
69 
70 /* Types for JPEG compression parameters and working tables. */
71 
72 
73 /* DCT coefficient quantization tables. */
74 
75 struct JQUANT_TBL{
76   /* This array gives the coefficient quantizers in natural array order
77    * (not the zigzag order in which they are stored in a JPEG DQT marker).
78    * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
79    */
80   UINT16 quantval[DCTSIZE2];	/* quantization step for each coefficient */
81   /* This field is used only during compression.  It's initialized FALSE when
82    * the table is created, and set TRUE when it's been output to the file.
83    * You could suppress output of a table by setting this to TRUE.
84    * (See jpeg_suppress_tables for an example.)
85    */
86   boolean sent_table;		/* TRUE when table has been output */
87 }
88 
89 
90 /* Huffman coding tables. */
91 
92 struct JHUFF_TBL {
93   /* These two fields directly represent the contents of a JPEG DHT marker */
94   UINT8 bits[17];		/* bits[k] = # of symbols with codes of */
95 				/* length k bits; bits[0] is unused */
96   UINT8 huffval[256];		/* The symbols, in order of incr code length */
97   /* This field is used only during compression.  It's initialized FALSE when
98    * the table is created, and set TRUE when it's been output to the file.
99    * You could suppress output of a table by setting this to TRUE.
100    * (See jpeg_suppress_tables for an example.)
101    */
102   boolean sent_table;		/* TRUE when table has been output */
103 }
104 
105 
106 /* Basic info about one component (color channel). */
107 
108 struct jpeg_component_info {
109   /* These values are fixed over the whole image. */
110   /* For compression, they must be supplied by parameter setup; */
111   /* for decompression, they are read from the SOF marker. */
112   int component_id;		/* identifier for this component (0..255) */
113   int component_index;		/* its index in SOF or cinfo->comp_info[] */
114   int h_samp_factor;		/* horizontal sampling factor (1..4) */
115   int v_samp_factor;		/* vertical sampling factor (1..4) */
116   int quant_tbl_no;		/* quantization table selector (0..3) */
117   /* These values may vary between scans. */
118   /* For compression, they must be supplied by parameter setup; */
119   /* for decompression, they are read from the SOS marker. */
120   /* The decompressor output side may not use these variables. */
121   int dc_tbl_no;		/* DC entropy table selector (0..3) */
122   int ac_tbl_no;		/* AC entropy table selector (0..3) */
123   
124   /* Remaining fields should be treated as private by applications. */
125   
126   /* These values are computed during compression or decompression startup: */
127   /* Component's size in DCT blocks.
128    * Any dummy blocks added to complete an MCU are not counted; therefore
129    * these values do not depend on whether a scan is interleaved or not.
130    */
131   JDIMENSION width_in_blocks;
132   JDIMENSION height_in_blocks;
133   /* Size of a DCT block in samples.  Always DCTSIZE for compression.
134    * For decompression this is the size of the output from one DCT block,
135    * reflecting any scaling we choose to apply during the IDCT step.
136    * Values of 1,2,4,8 are likely to be supported.  Note that different
137    * components may receive different IDCT scalings.
138    */
139 static if (JPEG_LIB_VERSION >= 70){
140   int DCT_h_scaled_size;
141   int DCT_v_scaled_size;
142 }else{
143   int DCT_scaled_size;
144 }
145   /* The downsampled dimensions are the component's actual, unpadded number
146    * of samples at the main buffer (preprocessing/compression interface), thus
147    * downsampled_width = ceil(image_width * Hi/Hmax)
148    * and similarly for height.  For decompression, IDCT scaling is included, so
149    * downsampled_width = ceil(image_width * Hi/Hmax * DCT_[h_]scaled_size/DCTSIZE)
150    */
151   JDIMENSION downsampled_width;	 /* actual width in samples */
152   JDIMENSION downsampled_height; /* actual height in samples */
153   /* This flag is used only for decompression.  In cases where some of the
154    * components will be ignored (eg grayscale output from YCbCr image),
155    * we can skip most computations for the unused components.
156    */
157   boolean component_needed;	/* do we need the value of this component? */
158 
159   /* These values are computed before starting a scan of the component. */
160   /* The decompressor output side may not use these variables. */
161   int MCU_width;		/* number of blocks per MCU, horizontally */
162   int MCU_height;		/* number of blocks per MCU, vertically */
163   int MCU_blocks;		/* MCU_width * MCU_height */
164   int MCU_sample_width;		/* MCU width in samples, MCU_width*DCT_[h_]scaled_size */
165   int last_col_width;		/* # of non-dummy blocks across in last MCU */
166   int last_row_height;		/* # of non-dummy blocks down in last MCU */
167 
168   /* Saved quantization table for component; NULL if none yet saved.
169    * See jdinput.c comments about the need for this information.
170    * This field is currently used only for decompression.
171    */
172   JQUANT_TBL * quant_table;
173 
174   /* Private per-component storage for DCT or IDCT subsystem. */
175   void * dct_table;
176 }
177 
178 
179 /* The script for encoding a multiple-scan file is an array of these: */
180 
181 struct jpeg_scan_info{
182   int comps_in_scan;		/* number of components encoded in this scan */
183   int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
184   int Ss, Se;			/* progressive JPEG spectral selection parms */
185   int Ah, Al;			/* progressive JPEG successive approx. parms */
186 }
187 
188 /* The decompressor can save APPn and COM markers in a list of these: */
189 
190 alias jpeg_marker_struct     * jpeg_saved_marker_ptr;
191 
192 struct jpeg_marker_struct {
193   jpeg_saved_marker_ptr next;	/* next in list, or NULL */
194   UINT8 marker;			/* marker code: JPEG_COM, or JPEG_APP0+n */
195   uint original_length;	/* # bytes of data in the file */
196   uint data_length;	/* # bytes of data saved at data[] */
197   JOCTET     * data;		/* the data contained in the marker */
198   /* the marker length word is not counted in data_length or original_length */
199 }
200 
201 /* Known color spaces. */
202 
203 enum JCS_EXTENSIONS = 1;
204 enum JCS_ALPHA_EXTENSIONS = 1;
205 
206 enum J_COLOR_SPACE{
207 	JCS_UNKNOWN,		/* error/unspecified */
208 	JCS_GRAYSCALE,		/* monochrome */
209 	JCS_RGB,		/* red/green/blue as specified by the RGB_RED, RGB_GREEN,
210 				   RGB_BLUE, and RGB_PIXELSIZE macros */
211 	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV) */
212 	JCS_CMYK,		/* C/M/Y/K */
213 	JCS_YCCK,		/* Y/Cb/Cr/K */
214 	JCS_EXT_RGB,		/* red/green/blue */
215 	JCS_EXT_RGBX,		/* red/green/blue/x */
216 	JCS_EXT_BGR,		/* blue/green/red */
217 	JCS_EXT_BGRX,		/* blue/green/red/x */
218 	JCS_EXT_XBGR,		/* x/blue/green/red */
219 	JCS_EXT_XRGB,		/* x/red/green/blue */
220 	/* When out_color_space it set to JCS_EXT_RGBX, JCS_EXT_BGRX,
221 	   JCS_EXT_XBGR, or JCS_EXT_XRGB during decompression, the X byte is
222 	   undefined, and in order to ensure the best performance,
223 	   libjpeg-turbo can set that byte to whatever value it wishes.  Use
224 	   the following colorspace constants to ensure that the X byte is set
225 	   to 0xFF, so that it can be interpreted as an opaque alpha
226 	   channel. */
227 	JCS_EXT_RGBA,		/* red/green/blue/alpha */
228 	JCS_EXT_BGRA,		/* blue/green/red/alpha */
229 	JCS_EXT_ABGR,		/* alpha/blue/green/red */
230 	JCS_EXT_ARGB		/* alpha/red/green/blue */
231 }
232 
233 /* DCT/IDCT algorithm options. */
234 
235 enum J_DCT_METHOD{
236 	JDCT_ISLOW,		/* slow but accurate integer algorithm */
237 	JDCT_IFAST,		/* faster, less accurate integer method */
238 	JDCT_FLOAT		/* floating-point: accurate, fast on fast HW */
239 }
240 
241 enum JDCT_DEFAULT = J_DCT_METHOD.JDCT_ISLOW;
242 enum JDCT_FASTEST = J_DCT_METHOD.JDCT_IFAST;
243 
244 /* Dithering options for decompression. */
245 
246 enum J_DITHER_MODE{
247 	JDITHER_NONE,		/* no dithering */
248 	JDITHER_ORDERED,	/* simple ordered dither */
249 	JDITHER_FS		/* Floyd-Steinberg error diffusion dither */
250 }
251 
252 
253 /* Common fields between JPEG compression and decompression master structs. */
254 
255 template jpeg_common_fields(){ 
256   jpeg_error_mgr * err;	/* Error handler module */
257   jpeg_memory_mgr * mem;	/* Memory manager module */
258   jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */
259   void * client_data;		/* Available for use by application */
260   boolean is_decompressor;	/* So common code can tell which is which */
261   int global_state;		/* For checking call sequence validity */
262 }
263 
264 /* Routines that are to be used by both halves of the library are declared
265  * to receive a pointer to this structure.  There are no actual instances of
266  * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
267  */
268 struct jpeg_common_struct {
269   mixin jpeg_common_fields!();	/* Fields common to both master struct types */
270   /* Additional fields follow in an actual jpeg_compress_struct or
271    * jpeg_decompress_struct.  All three structs must agree on these
272    * initial fields!  (This would be a lot cleaner in C++.)
273    */
274 }
275 
276 alias jpeg_common_struct * j_common_ptr;
277 alias jpeg_compress_struct * j_compress_ptr;
278 alias jpeg_decompress_struct * j_decompress_ptr;
279 
280 
281 /* Master record for a compression instance */
282 
283 struct jpeg_compress_struct {
284   mixin jpeg_common_fields!();		/* Fields shared with jpeg_decompress_struct */
285 
286   /* Destination for compressed data */
287   jpeg_destination_mgr * dest;
288 
289   /* Description of source image --- these fields must be filled in by
290    * outer application before starting compression.  in_color_space must
291    * be correct before you can even call jpeg_set_defaults().
292    */
293 
294   JDIMENSION image_width;	/* input image width */
295   JDIMENSION image_height;	/* input image height */
296   int input_components;		/* # of color components in input image */
297   J_COLOR_SPACE in_color_space;	/* colorspace of input image */
298 
299   double input_gamma;		/* image gamma of input image */
300 
301   /* Compression parameters --- these fields must be set before calling
302    * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to
303    * initialize everything to reasonable defaults, then changing anything
304    * the application specifically wants to change.  That way you won't get
305    * burnt when new parameters are added.  Also note that there are several
306    * helper routines to simplify changing parameters.
307    */
308 
309 static if (JPEG_LIB_VERSION >= 70){
310   uint scale_num, scale_denom; /* fraction by which to scale image */
311 
312   JDIMENSION jpeg_width;	/* scaled JPEG image width */
313   JDIMENSION jpeg_height;	/* scaled JPEG image height */
314   /* Dimensions of actual JPEG image that will be written to file,
315    * derived from input dimensions by scaling factors above.
316    * These fields are computed by jpeg_start_compress().
317    * You can also use jpeg_calc_jpeg_dimensions() to determine these values
318    * in advance of calling jpeg_start_compress().
319    */
320 }
321 
322   int data_precision;		/* bits of precision in image data */
323 
324   int num_components;		/* # of color components in JPEG image */
325   J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
326 
327   jpeg_component_info * comp_info;
328   /* comp_info[i] describes component that appears i'th in SOF */
329 
330   JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
331 static if (JPEG_LIB_VERSION >= 70){
332   int q_scale_factor[NUM_QUANT_TBLS];
333 }
334   /* ptrs to coefficient quantization tables, or NULL if not defined,
335    * and corresponding scale factors (percentage, initialized 100).
336    */
337 
338   JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
339   JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
340   /* ptrs to Huffman coding tables, or NULL if not defined */
341 
342   UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
343   UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
344   UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
345 
346   int num_scans;		/* # of entries in scan_info array */
347   const(jpeg_scan_info) * scan_info; /* script for multi-scan file, or NULL */
348   /* The default value of scan_info is NULL, which causes a single-scan
349    * sequential JPEG file to be emitted.  To create a multi-scan file,
350    * set num_scans and scan_info to point to an array of scan definitions.
351    */
352 
353   boolean raw_data_in;		/* TRUE=caller supplies downsampled data */
354   boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
355   boolean optimize_coding;	/* TRUE=optimize entropy encoding parms */
356   boolean CCIR601_sampling;	/* TRUE=first samples are cosited */
357 static if (JPEG_LIB_VERSION >= 70){
358   boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
359 }
360   int smoothing_factor;		/* 1..100, or 0 for no input smoothing */
361   J_DCT_METHOD dct_method;	/* DCT algorithm selector */
362 
363   /* The restart interval can be specified in absolute MCUs by setting
364    * restart_interval, or in MCU rows by setting restart_in_rows
365    * (in which case the correct restart_interval will be figured
366    * for each scan).
367    */
368   uint restart_interval; /* MCUs per restart, or 0 for no restart */
369   int restart_in_rows;		/* if > 0, MCU rows per restart interval */
370 
371   /* Parameters controlling emission of special markers. */
372 
373   boolean write_JFIF_header;	/* should a JFIF marker be written? */
374   UINT8 JFIF_major_version;	/* What to write for the JFIF version number */
375   UINT8 JFIF_minor_version;
376   /* These three values are not used by the JPEG code, merely copied */
377   /* into the JFIF APP0 marker.  density_unit can be 0 for unknown, */
378   /* 1 for dots/inch, or 2 for dots/cm.  Note that the pixel aspect */
379   /* ratio is defined by X_density/Y_density even when density_unit=0. */
380   UINT8 density_unit;		/* JFIF code for pixel size units */
381   UINT16 X_density;		/* Horizontal pixel density */
382   UINT16 Y_density;		/* Vertical pixel density */
383   boolean write_Adobe_marker;	/* should an Adobe marker be written? */
384   
385   /* State variable: index of next scanline to be written to
386    * jpeg_write_scanlines().  Application may use this to control its
387    * processing loop, e.g., "while (next_scanline < image_height)".
388    */
389 
390   JDIMENSION next_scanline;	/* 0 .. image_height-1  */
391 
392   /* Remaining fields are known throughout compressor, but generally
393    * should not be touched by a surrounding application.
394    */
395 
396   /*
397    * These fields are computed during compression startup
398    */
399   boolean progressive_mode;	/* TRUE if scan script uses progressive mode */
400   int max_h_samp_factor;	/* largest h_samp_factor */
401   int max_v_samp_factor;	/* largest v_samp_factor */
402 
403 static if (JPEG_LIB_VERSION >= 70){
404   int min_DCT_h_scaled_size;	/* smallest DCT_h_scaled_size of any component */
405   int min_DCT_v_scaled_size;	/* smallest DCT_v_scaled_size of any component */
406 }
407 
408   JDIMENSION total_iMCU_rows;	/* # of iMCU rows to be input to coef ctlr */
409   /* The coefficient controller receives data in units of MCU rows as defined
410    * for fully interleaved scans (whether the JPEG file is interleaved or not).
411    * There are v_samp_factor * DCTSIZE sample rows of each component in an
412    * "iMCU" (interleaved MCU) row.
413    */
414   
415   /*
416    * These fields are valid during any one scan.
417    * They describe the components and MCUs actually appearing in the scan.
418    */
419   int comps_in_scan;		/* # of JPEG components in this scan */
420   jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
421   /* *cur_comp_info[i] describes component that appears i'th in SOS */
422   
423   JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
424   JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */
425   
426   int blocks_in_MCU;		/* # of DCT blocks per MCU */
427   int MCU_membership[C_MAX_BLOCKS_IN_MCU];
428   /* MCU_membership[i] is index in cur_comp_info of component owning */
429   /* i'th block in an MCU */
430 
431   int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */
432 
433 static if (JPEG_LIB_VERSION >= 80){
434   int block_size;		/* the basic DCT block size: 1..16 */
435   const(int) * natural_order;	/* natural-order position array */
436   int lim_Se;			/* min( Se, DCTSIZE2-1 ) */
437 }
438 
439   /*
440    * Links to compression subobjects (methods and private variables of modules)
441    */
442   jpeg_comp_master * master;
443   jpeg_c_main_controller * main;
444   jpeg_c_prep_controller * prep;
445   jpeg_c_coef_controller * coef;
446   jpeg_marker_writer * marker;
447   jpeg_color_converter * cconvert;
448   jpeg_downsampler * downsample;
449   jpeg_forward_dct * fdct;
450   jpeg_entropy_encoder * entropy;
451   jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
452   int script_space_size;
453 }
454 
455 
456 /* Master record for a decompression instance */
457 
458 struct jpeg_decompress_struct {
459   mixin jpeg_common_fields!();		/* Fields shared with jpeg_compress_struct */
460 
461   /* Source of compressed data */
462   jpeg_source_mgr * src;
463 
464   /* Basic description of image --- filled in by jpeg_read_header(). */
465   /* Application may inspect these values to decide how to process image. */
466 
467   JDIMENSION image_width;	/* nominal image width (from SOF marker) */
468   JDIMENSION image_height;	/* nominal image height */
469   int num_components;		/* # of color components in JPEG image */
470   J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
471 
472   /* Decompression processing parameters --- these fields must be set before
473    * calling jpeg_start_decompress().  Note that jpeg_read_header() initializes
474    * them to default values.
475    */
476 
477   J_COLOR_SPACE out_color_space; /* colorspace for output */
478 
479   uint scale_num, scale_denom; /* fraction by which to scale image */
480 
481   double output_gamma;		/* image gamma wanted in output */
482 
483   boolean buffered_image;	/* TRUE=multiple output passes */
484   boolean raw_data_out;		/* TRUE=downsampled data wanted */
485 
486   J_DCT_METHOD dct_method;	/* IDCT algorithm selector */
487   boolean do_fancy_upsampling;	/* TRUE=apply fancy upsampling */
488   boolean do_block_smoothing;	/* TRUE=apply interblock smoothing */
489 
490   boolean quantize_colors;	/* TRUE=colormapped output wanted */
491   /* the following are ignored if not quantize_colors: */
492   J_DITHER_MODE dither_mode;	/* type of color dithering to use */
493   boolean two_pass_quantize;	/* TRUE=use two-pass color quantization */
494   int desired_number_of_colors;	/* max # colors to use in created colormap */
495   /* these are significant only in buffered-image mode: */
496   boolean enable_1pass_quant;	/* enable future use of 1-pass quantizer */
497   boolean enable_external_quant;/* enable future use of external colormap */
498   boolean enable_2pass_quant;	/* enable future use of 2-pass quantizer */
499 
500   /* Description of actual output image that will be returned to application.
501    * These fields are computed by jpeg_start_decompress().
502    * You can also use jpeg_calc_output_dimensions() to determine these values
503    * in advance of calling jpeg_start_decompress().
504    */
505 
506   JDIMENSION output_width;	/* scaled image width */
507   JDIMENSION output_height;	/* scaled image height */
508   int out_color_components;	/* # of color components in out_color_space */
509   int output_components;	/* # of color components returned */
510   /* output_components is 1 (a colormap index) when quantizing colors;
511    * otherwise it equals out_color_components.
512    */
513   int rec_outbuf_height;	/* min recommended height of scanline buffer */
514   /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
515    * high, space and time will be wasted due to unnecessary data copying.
516    * Usually rec_outbuf_height will be 1 or 2, at most 4.
517    */
518 
519   /* When quantizing colors, the output colormap is described by these fields.
520    * The application can supply a colormap by setting colormap non-NULL before
521    * calling jpeg_start_decompress; otherwise a colormap is created during
522    * jpeg_start_decompress or jpeg_start_output.
523    * The map has out_color_components rows and actual_number_of_colors columns.
524    */
525   int actual_number_of_colors;	/* number of entries in use */
526   JSAMPARRAY colormap;		/* The color map as a 2-D pixel array */
527 
528   /* State variables: these variables indicate the progress of decompression.
529    * The application may examine these but must not modify them.
530    */
531 
532   /* Row index of next scanline to be read from jpeg_read_scanlines().
533    * Application may use this to control its processing loop, e.g.,
534    * "while (output_scanline < output_height)".
535    */
536   JDIMENSION output_scanline;	/* 0 .. output_height-1  */
537 
538   /* Current input scan number and number of iMCU rows completed in scan.
539    * These indicate the progress of the decompressor input side.
540    */
541   int input_scan_number;	/* Number of SOS markers seen so far */
542   JDIMENSION input_iMCU_row;	/* Number of iMCU rows completed */
543 
544   /* The "output scan number" is the notional scan being displayed by the
545    * output side.  The decompressor will not allow output scan/row number
546    * to get ahead of input scan/row, but it can fall arbitrarily far behind.
547    */
548   int output_scan_number;	/* Nominal scan number being displayed */
549   JDIMENSION output_iMCU_row;	/* Number of iMCU rows read */
550 
551   /* Current progression status.  coef_bits[c][i] indicates the precision
552    * with which component c's DCT coefficient i (in zigzag order) is known.
553    * It is -1 when no data has yet been received, otherwise it is the point
554    * transform (shift) value for the most recent scan of the coefficient
555    * (thus, 0 at completion of the progression).
556    * This pointer is NULL when reading a non-progressive file.
557    */
558   int[DCTSIZE2] *coef_bits;	/* -1 or current Al value for each coef */
559 
560   /* Internal JPEG parameters --- the application usually need not look at
561    * these fields.  Note that the decompressor output side may not use
562    * any parameters that can change between scans.
563    */
564 
565   /* Quantization and Huffman tables are carried forward across input
566    * datastreams when processing abbreviated JPEG datastreams.
567    */
568 
569   JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
570   /* ptrs to coefficient quantization tables, or NULL if not defined */
571 
572   JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
573   JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
574   /* ptrs to Huffman coding tables, or NULL if not defined */
575 
576   /* These parameters are never carried across datastreams, since they
577    * are given in SOF/SOS markers or defined to be reset by SOI.
578    */
579 
580   int data_precision;		/* bits of precision in image data */
581 
582   jpeg_component_info * comp_info;
583   /* comp_info[i] describes component that appears i'th in SOF */
584 
585 static if (JPEG_LIB_VERSION >= 80){
586   boolean is_baseline;		/* TRUE if Baseline SOF0 encountered */
587 }
588   boolean progressive_mode;	/* TRUE if SOFn specifies progressive mode */
589   boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
590 
591   UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
592   UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
593   UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
594 
595   uint restart_interval; /* MCUs per restart interval, or 0 for no restart */
596 
597   /* These fields record data obtained from optional markers recognized by
598    * the JPEG library.
599    */
600   boolean saw_JFIF_marker;	/* TRUE iff a JFIF APP0 marker was found */
601   /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
602   UINT8 JFIF_major_version;	/* JFIF version number */
603   UINT8 JFIF_minor_version;
604   UINT8 density_unit;		/* JFIF code for pixel size units */
605   UINT16 X_density;		/* Horizontal pixel density */
606   UINT16 Y_density;		/* Vertical pixel density */
607   boolean saw_Adobe_marker;	/* TRUE iff an Adobe APP14 marker was found */
608   UINT8 Adobe_transform;	/* Color transform code from Adobe marker */
609 
610   boolean CCIR601_sampling;	/* TRUE=first samples are cosited */
611 
612   /* Aside from the specific data retained from APPn markers known to the
613    * library, the uninterpreted contents of any or all APPn and COM markers
614    * can be saved in a list for examination by the application.
615    */
616   jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
617 
618   /* Remaining fields are known throughout decompressor, but generally
619    * should not be touched by a surrounding application.
620    */
621 
622   /*
623    * These fields are computed during decompression startup
624    */
625   int max_h_samp_factor;	/* largest h_samp_factor */
626   int max_v_samp_factor;	/* largest v_samp_factor */
627 
628 static if (JPEG_LIB_VERSION >= 70){
629   int min_DCT_h_scaled_size;	/* smallest DCT_h_scaled_size of any component */
630   int min_DCT_v_scaled_size;	/* smallest DCT_v_scaled_size of any component */
631 }else{
632   int min_DCT_scaled_size;	/* smallest DCT_scaled_size of any component */
633 }
634 
635   JDIMENSION total_iMCU_rows;	/* # of iMCU rows in image */
636   /* The coefficient controller's input and output progress is measured in
637    * units of "iMCU" (interleaved MCU) rows.  These are the same as MCU rows
638    * in fully interleaved JPEG scans, but are used whether the scan is
639    * interleaved or not.  We define an iMCU row as v_samp_factor DCT block
640    * rows of each component.  Therefore, the IDCT output contains
641    * v_samp_factor*DCT_[v_]scaled_size sample rows of a component per iMCU row.
642    */
643 
644   JSAMPLE * sample_range_limit; /* table for fast range-limiting */
645 
646   /*
647    * These fields are valid during any one scan.
648    * They describe the components and MCUs actually appearing in the scan.
649    * Note that the decompressor output side must not use these fields.
650    */
651   int comps_in_scan;		/* # of JPEG components in this scan */
652   jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
653   /* *cur_comp_info[i] describes component that appears i'th in SOS */
654 
655   JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
656   JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */
657 
658   int blocks_in_MCU;		/* # of DCT blocks per MCU */
659   int MCU_membership[D_MAX_BLOCKS_IN_MCU];
660   /* MCU_membership[i] is index in cur_comp_info of component owning */
661   /* i'th block in an MCU */
662 
663   int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */
664 
665 static if (JPEG_LIB_VERSION >= 80){
666   /* These fields are derived from Se of first SOS marker.
667    */
668   int block_size;		/* the basic DCT block size: 1..16 */
669   const(int) * natural_order; /* natural-order position array for entropy decode */
670   int lim_Se;			/* min( Se, DCTSIZE2-1 ) for entropy decode */
671 }
672 
673   /* This field is shared between entropy decoder and marker parser.
674    * It is either zero or the code of a JPEG marker that has been
675    * read from the data source, but has not yet been processed.
676    */
677   int unread_marker;
678 
679   /*
680    * Links to decompression subobjects (methods, private variables of modules)
681    */
682   jpeg_decomp_master * master;
683   jpeg_d_main_controller * main;
684   jpeg_d_coef_controller * coef;
685   jpeg_d_post_controller * post;
686   jpeg_input_controller * inputctl;
687   jpeg_marker_reader * marker;
688   jpeg_entropy_decoder * entropy;
689   jpeg_inverse_dct * idct;
690   jpeg_upsampler * upsample;
691   jpeg_color_deconverter * cconvert;
692   jpeg_color_quantizer * cquantize;
693 }
694 
695 
696 /* "Object" declarations for JPEG modules that may be supplied or called
697  * directly by the surrounding application.
698  * As with all objects in the JPEG library, these structs only define the
699  * publicly visible methods and state variables of a module.  Additional
700  * private fields may exist after the public ones.
701  */
702 
703 
704 /* Error handler object */
705 
706 struct jpeg_error_mgr {
707   /* Error exit handler: does not return to caller */
708   void function(j_common_ptr cinfo) error_exit;
709   /* Conditionally emit a trace or warning message */
710   void function(j_common_ptr cinfo, int msg_level) emit_message;
711   /* Routine that actually outputs a trace or error message */
712   void function(j_common_ptr cinfo) output_message;
713   /* Format a message string for the most recent JPEG error or message */
714   void function(j_common_ptr cinfo, char * buffer) format_message;
715   enum JMSG_LENGTH_MAX  = 200;	/* recommended size of format_message buffer */
716   /* Reset error state variables at start of a new image */
717   void function(j_common_ptr cinfo) reset_error_mgr;
718   
719   /* The message ID code and any parameters are saved here.
720    * A message can have one string parameter or up to 8 int parameters.
721    */
722   int msg_code;
723   enum JMSG_STR_PARM_MAX  = 80;
724   union msg_parm_t{
725     int i[8];
726     char s[JMSG_STR_PARM_MAX];
727   }
728   msg_parm_t msg_parm;
729   
730   /* Standard state variables for error facility */
731   
732   int trace_level;		/* max msg_level that will be displayed */
733   
734   /* For recoverable corrupt-data errors, we emit a warning message,
735    * but keep going unless emit_message chooses to abort.  emit_message
736    * should count warnings in num_warnings.  The surrounding application
737    * can check for bad data by seeing if num_warnings is nonzero at the
738    * end of processing.
739    */
740   int num_warnings;		/* number of corrupt-data warnings */
741 
742   /* These fields point to the table(s) of error message strings.
743    * An application can change the table pointer to switch to a different
744    * message list (typically, to change the language in which errors are
745    * reported).  Some applications may wish to add additional error codes
746    * that will be handled by the JPEG library error mechanism; the second
747    * table pointer is used for this purpose.
748    *
749    * First table includes all errors generated by JPEG library itself.
750    * Error code 0 is reserved for a "no such error string" message.
751    */
752   const(char*) * jpeg_message_table; /* Library errors */
753   int last_jpeg_message;    /* Table contains strings 0..last_jpeg_message */
754   /* Second table can be added by application (see cjpeg/djpeg for example).
755    * It contains strings numbered first_addon_message..last_addon_message.
756    */
757   const(char*) * addon_message_table; /* Non-library errors */
758   int first_addon_message;	/* code for first string in addon table */
759   int last_addon_message;	/* code for last string in addon table */
760 }
761 
762 
763 /* Progress monitor object */
764 
765 struct jpeg_progress_mgr {
766   void function(j_common_ptr cinfo) progress_monitor;
767 
768   int pass_counter;		/* work units completed in this pass */
769   int pass_limit;		/* total number of work units in this pass */
770   int completed_passes;		/* passes completed so far */
771   int total_passes;		/* total number of passes expected */
772 }
773 
774 
775 /* Data destination object for compression */
776 
777 struct jpeg_destination_mgr {
778   JOCTET * next_output_byte;	/* => next byte to write in buffer */
779   size_t free_in_buffer;	/* # of byte spaces remaining in buffer */
780 
781   void function(j_compress_ptr cinfo) init_destination;
782   boolean function(j_compress_ptr cinfo) empty_output_buffer;
783   void function(j_compress_ptr cinfo) term_destination;
784 }
785 
786 
787 /* Data source object for decompression */
788 
789 struct jpeg_source_mgr {
790   const(JOCTET) * next_input_byte; /* => next byte to read from buffer */
791   size_t bytes_in_buffer;	/* # of bytes remaining in buffer */
792 
793   void function(j_decompress_ptr cinfo) init_source;
794   boolean function(j_decompress_ptr cinfo) fill_input_buffer;
795   void function(j_decompress_ptr cinfo, int num_bytes) skip_input_data;
796   boolean function(j_decompress_ptr cinfo, int desired) resync_to_restart;
797   void function(j_decompress_ptr cinfo) term_source;
798 }
799 
800 
801 /* Memory manager object.
802  * Allocates "small" objects (a few K total), "large" objects (tens of K),
803  * and "really big" objects (virtual arrays with backing store if needed).
804  * The memory manager does not allow individual objects to be freed; rather,
805  * each created object is assigned to a pool, and whole pools can be freed
806  * at once.  This is faster and more convenient than remembering exactly what
807  * to free, especially where malloc()/free() are not too speedy.
808  * NB: alloc routines never return NULL.  They exit to error_exit if not
809  * successful.
810  */
811 
812 enum JPOOL_PERMANENT	= 0;	/* lasts until master record is destroyed */
813 enum JPOOL_IMAGE	= 1;	/* lasts until done with image/datastream */
814 enum JPOOL_NUMPOOLS	= 2;
815 
816 alias jvirt_sarray_control * jvirt_sarray_ptr;
817 alias jvirt_barray_control * jvirt_barray_ptr;
818 
819 
820 struct jpeg_memory_mgr {
821   /* Method pointers */
822   void * function(j_common_ptr cinfo, int pool_id,
823 				size_t sizeofobject) alloc_small;
824   void * function(j_common_ptr cinfo, int pool_id,
825 				     size_t sizeofobject) alloc_large;
826   JSAMPARRAY function(j_common_ptr cinfo, int pool_id,
827 				     JDIMENSION samplesperrow,
828 				     JDIMENSION numrows) alloc_sarray;
829   JBLOCKARRAY function(j_common_ptr cinfo, int pool_id,
830 				      JDIMENSION blocksperrow,
831 				      JDIMENSION numrows) alloc_barray;
832   jvirt_sarray_ptr function(j_common_ptr cinfo,
833 						  int pool_id,
834 						  boolean pre_zero,
835 						  JDIMENSION samplesperrow,
836 						  JDIMENSION numrows,
837 						  JDIMENSION maxaccess) request_virt_sarray;
838   jvirt_barray_ptr function(j_common_ptr cinfo,
839 						  int pool_id,
840 						  boolean pre_zero,
841 						  JDIMENSION blocksperrow,
842 						  JDIMENSION numrows,
843 						  JDIMENSION maxaccess) request_virt_barray;
844   void function(j_common_ptr cinfo) realize_virt_arrays;
845   JSAMPARRAY function(j_common_ptr cinfo,
846 					   jvirt_sarray_ptr ptr,
847 					   JDIMENSION start_row,
848 					   JDIMENSION num_rows,
849 					   boolean writable) access_virt_sarray;
850   JBLOCKARRAY function(j_common_ptr cinfo,
851 					    jvirt_barray_ptr ptr,
852 					    JDIMENSION start_row,
853 					    JDIMENSION num_rows,
854 					    boolean writable) access_virt_barray;
855   void function(j_common_ptr cinfo, int pool_id) free_pool;
856   void function(j_common_ptr cinfo) self_destruct;
857 
858   /* Limit on memory allocation for this JPEG object.  (Note that this is
859    * merely advisory, not a guaranteed maximum; it only affects the space
860    * used for virtual-array buffers.)  May be changed by outer application
861    * after creating the JPEG object.
862    */
863   int max_memory_to_use;
864 
865   /* Maximum allocation request accepted by alloc_large. */
866   int max_alloc_chunk;
867 }
868 
869 
870 /* Routine signature for application-supplied marker processing methods.
871  * Need not pass marker code since it is stored in cinfo->unread_marker.
872  */
873 alias boolean function(j_decompress_ptr cinfo) jpeg_marker_parser_method;
874 
875 
876 /* Declarations for routines called by application.
877  * The JPP macro hides prototype parameters from compilers that can't cope.
878  * Note JPP requires double parentheses.
879  */
880 
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 version(NEED_SHORT_EXTERNAL_NAMES){
891 alias jpeg_std_error		jStdError;
892 alias jpeg_CreateCompress	jCreaCompress;
893 alias jpeg_CreateDecompress	jCreaDecompress;
894 alias jpeg_destroy_compress	jDestCompress;
895 alias jpeg_destroy_decompress	jDestDecompress;
896 alias jpeg_stdio_dest		jStdDest;
897 alias jpeg_stdio_src		jStdSrc;
898 static if (JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)){
899 alias jpeg_mem_dest		jMemDest;
900 alias jpeg_mem_src		jMemSrc;
901 }
902 alias jpeg_set_defaults		jSetDefaults;
903 alias jpeg_set_colorspace	jSetColorspace;
904 alias jpeg_default_colorspace	jDefColorspace;
905 alias jpeg_set_quality		jSetQuality;
906 alias jpeg_set_linear_quality	jSetLQuality;
907 static if (JPEG_LIB_VERSION >= 70){
908 alias jpeg_default_qtables	jDefQTables;
909 }
910 alias jpeg_add_quant_table	jAddQuantTable;
911 alias jpeg_quality_scaling	jQualityScaling;
912 alias jpeg_simple_progression	jSimProgress;
913 alias jpeg_suppress_tables	jSuppressTables;
914 alias jpeg_alloc_quant_table	jAlcQTable;
915 alias jpeg_alloc_huff_table	jAlcHTable;
916 alias jpeg_start_compress	jStrtCompress;
917 alias jpeg_write_scanlines	jWrtScanlines;
918 alias jpeg_finish_compress	jFinCompress;
919 static if (JPEG_LIB_VERSION >= 70){
920 alias jpeg_calc_jpeg_dimensions	jCjpegDimensions;
921 }
922 alias jpeg_write_raw_data	jWrtRawData;
923 alias jpeg_write_marker		jWrtMarker;
924 alias jpeg_write_m_header	jWrtMHeader;
925 alias jpeg_write_m_byte		jWrtMByte;
926 alias jpeg_write_tables		jWrtTables;
927 alias jpeg_read_header		jReadHeader;
928 alias jpeg_start_decompress	jStrtDecompress;
929 alias jpeg_read_scanlines	jReadScanlines;
930 alias jpeg_finish_decompress	jFinDecompress;
931 alias jpeg_read_raw_data	jReadRawData;
932 alias jpeg_has_multiple_scans	jHasMultScn;
933 alias jpeg_start_output		jStrtOutput;
934 alias jpeg_finish_output	jFinOutput;
935 alias jpeg_input_complete	jInComplete;
936 alias jpeg_new_colormap		jNewCMap;
937 alias jpeg_consume_input	jConsumeInput;
938 static if (JPEG_LIB_VERSION >= 80){
939 alias jpeg_core_output_dimensions	jCoreDimensions;
940 }
941 alias jpeg_calc_output_dimensions	jCalcDimensions;
942 alias jpeg_save_markers		jSaveMarkers;
943 alias jpeg_set_marker_processor	jSetMarker;
944 alias jpeg_read_coefficients	jReadCoefs;
945 alias jpeg_write_coefficients	jWrtCoefs;
946 alias jpeg_copy_critical_parameters	jCopyCrit;
947 alias jpeg_abort_compress	jAbrtCompress;
948 alias jpeg_abort_decompress	jAbrtDecompress;
949 alias jpeg_abort		jAbort;
950 alias jpeg_destroy		jDestroy;
951 alias jpeg_resync_to_restart	jResyncRestart;
952 } /* NEED_SHORT_EXTERNAL_NAMES */
953 
954 
955 /* Default error-management setup */
956 jpeg_error_mgr * jpeg_std_error
957 	(jpeg_error_mgr * err);
958 
959 /* Initialization of JPEG compression objects.
960  * jpeg_create_compress() and jpeg_create_decompress() are the exported
961  * names that applications should call.  These expand to calls on
962  * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
963  * passed for version mismatch checking.
964  * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
965  */
966 auto jpeg_create_compress(j_compress_ptr cinfo) {
967     return jpeg_CreateCompress(cinfo, JPEG_LIB_VERSION, 
968 			jpeg_compress_struct.sizeof);
969 }
970 auto jpeg_create_decompress(j_decompress_ptr cinfo) {
971     return jpeg_CreateDecompress(cinfo, JPEG_LIB_VERSION,
972 			  jpeg_decompress_struct.sizeof);
973 }
974 void jpeg_CreateCompress(j_compress_ptr cinfo,
975 				      int _version, size_t structsize);
976 void jpeg_CreateDecompress(j_decompress_ptr cinfo,
977 					int _version, size_t structsize);
978 /* Destruction of JPEG compression objects */
979 void jpeg_destroy_compress(j_compress_ptr cinfo);
980 void jpeg_destroy_decompress(j_decompress_ptr cinfo);
981 
982 /* Standard data source and destination managers: stdio streams. */
983 /* Caller is responsible for opening the file before and closing after. */
984 import core.stdc.stdio : FILE;
985 void jpeg_stdio_dest(j_compress_ptr cinfo, FILE * outfile);
986 void jpeg_stdio_src(j_decompress_ptr cinfo, FILE * infile);
987 
988 static if (JPEG_LIB_VERSION >= 80 || MEM_SRCDST_SUPPORTED){
989 /* Data source and destination managers: memory buffers. */
990 void jpeg_mem_dest(j_compress_ptr cinfo,
991 			       ubyte ** outbuffer,
992 			       uint * outsize);
993 void jpeg_mem_src(j_decompress_ptr cinfo,
994 			      ubyte * inbuffer,
995 			      uint insize);
996 }
997 
998 /* Default parameter setup for compression */
999 void jpeg_set_defaults(j_compress_ptr cinfo);
1000 /* Compression parameter setup aids */
1001 void jpeg_set_colorspace(j_compress_ptr cinfo,
1002 				      J_COLOR_SPACE colorspace);
1003 void jpeg_default_colorspace(j_compress_ptr cinfo);
1004 void jpeg_set_quality(j_compress_ptr cinfo, int quality,
1005 				   boolean force_baseline);
1006 void jpeg_set_linear_quality(j_compress_ptr cinfo,
1007 					  int scale_factor,
1008 					  boolean force_baseline);
1009 static if (JPEG_LIB_VERSION >= 70){
1010 void jpeg_default_qtables(j_compress_ptr cinfo,
1011 				       boolean force_baseline);
1012 }
1013 void jpeg_add_quant_table(j_compress_ptr cinfo, int which_tbl,
1014 				       const(uint) *basic_table,
1015 				       int scale_factor,
1016 				       boolean force_baseline);
1017 int jpeg_quality_scaling(int quality);
1018 void jpeg_simple_progression(j_compress_ptr cinfo);
1019 void jpeg_suppress_tables(j_compress_ptr cinfo,
1020 				       boolean suppress);
1021 JQUANT_TBL * jpeg_alloc_quant_table(j_common_ptr cinfo);
1022 JHUFF_TBL * jpeg_alloc_huff_table(j_common_ptr cinfo);
1023 
1024 /* Main entry points for compression */
1025 void jpeg_start_compress(j_compress_ptr cinfo,
1026 				      boolean write_all_tables);
1027 JDIMENSION jpeg_write_scanlines(j_compress_ptr cinfo,
1028 					     in JSAMPARRAY scanlines,
1029 					     JDIMENSION num_lines);
1030 void jpeg_finish_compress(j_compress_ptr cinfo);
1031 
1032 static if (JPEG_LIB_VERSION >= 70){
1033 /* Precalculate JPEG dimensions for current compression parameters. */
1034 void jpeg_calc_jpeg_dimensions(j_compress_ptr cinfo);
1035 }
1036 
1037 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
1038 JDIMENSION jpeg_write_raw_data(j_compress_ptr cinfo,
1039 					    JSAMPIMAGE data,
1040 					    JDIMENSION num_lines);
1041 
1042 /* Write a special marker.  See libjpeg.txt concerning safe usage. */
1043 void jpeg_write_marker
1044 (j_compress_ptr cinfo, int marker,
1045 	     const(JOCTET) * dataptr, uint datalen);
1046 /* Same, but piecemeal. */
1047 void jpeg_write_m_header
1048 (j_compress_ptr cinfo, int marker, uint datalen);
1049 void jpeg_write_m_byte
1050 (j_compress_ptr cinfo, int val);
1051 
1052 /* Alternate compression function: just write an abbreviated table file */
1053 void jpeg_write_tables(j_compress_ptr cinfo);
1054 
1055 /* Decompression startup: read start of JPEG datastream to see what's there */
1056 int jpeg_read_header(j_decompress_ptr cinfo,
1057 				  boolean require_image);
1058 /* Return value is one of: */
1059 enum JPEG_SUSPENDED		= 0; /* Suspended due to lack of input data */
1060 enum JPEG_HEADER_OK		= 1; /* Found valid image datastream */
1061 enum JPEG_HEADER_TABLES_ONLY	= 2; /* Found valid table-specs-only datastream */
1062 /* If you pass require_image = TRUE (normal case), you need not check for
1063  * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
1064  * JPEG_SUSPENDED is only possible if you use a data source module that can
1065  * give a suspension return (the stdio source module doesn't).
1066  */
1067 
1068 /* Main entry points for decompression */
1069 boolean jpeg_start_decompress(j_decompress_ptr cinfo);
1070 JDIMENSION jpeg_read_scanlines(j_decompress_ptr cinfo,
1071 					    JSAMPARRAY scanlines,
1072 					    JDIMENSION max_lines);
1073 boolean jpeg_finish_decompress(j_decompress_ptr cinfo);
1074 
1075 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
1076 JDIMENSION jpeg_read_raw_data(j_decompress_ptr cinfo,
1077 					   JSAMPIMAGE data,
1078 					   JDIMENSION max_lines);
1079 
1080 /* Additional entry points for buffered-image mode. */
1081 boolean jpeg_has_multiple_scans(j_decompress_ptr cinfo);
1082 boolean jpeg_start_output(j_decompress_ptr cinfo,
1083 				       int scan_number);
1084 boolean jpeg_finish_output(j_decompress_ptr cinfo);
1085 boolean jpeg_input_complete(j_decompress_ptr cinfo);
1086 void jpeg_new_colormap(j_decompress_ptr cinfo);
1087 int jpeg_consume_input(j_decompress_ptr cinfo);
1088 /* Return value is one of: */
1089 /* enum JPEG_SUSPENDED	= 0;    Suspended due to lack of input data */
1090 enum JPEG_REACHED_SOS	= 1; /* Reached start of new scan */
1091 enum JPEG_REACHED_EOI	= 2; /* Reached end of image */
1092 enum JPEG_ROW_COMPLETED	= 3; /* Completed one iMCU row */
1093 enum JPEG_SCAN_COMPLETED	= 4; /* Completed last iMCU row of a scan */
1094 
1095 /* Precalculate output dimensions for current decompression parameters. */
1096 static if (JPEG_LIB_VERSION >= 80){
1097 void jpeg_core_output_dimensions(j_decompress_ptr cinfo);
1098 }
1099 void jpeg_calc_output_dimensions(j_decompress_ptr cinfo);
1100 
1101 /* Control saving of COM and APPn markers into marker_list. */
1102 void jpeg_save_markers
1103 (j_decompress_ptr cinfo, int marker_code,
1104 	     uint length_limit);
1105 
1106 /* Install a special processing method for COM or APPn markers. */
1107 void jpeg_set_marker_processor
1108 (j_decompress_ptr cinfo, int marker_code,
1109 	     jpeg_marker_parser_method routine);
1110 
1111 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1112 jvirt_barray_ptr * jpeg_read_coefficients(j_decompress_ptr cinfo);
1113 void jpeg_write_coefficients(j_compress_ptr cinfo,
1114 					  jvirt_barray_ptr * coef_arrays);
1115 void jpeg_copy_critical_parameters(j_decompress_ptr srcinfo,
1116 						j_compress_ptr dstinfo);
1117 
1118 /* If you choose to abort compression or decompression before completing
1119  * jpeg_finish_(de)compress, then you need to clean up to release memory,
1120  * temporary files, etc.  You can just call jpeg_destroy_(de)compress
1121  * if you're done with the JPEG object, but if you want to clean it up and
1122  * reuse it, call this:
1123  */
1124 void jpeg_abort_compress(j_compress_ptr cinfo);
1125 void jpeg_abort_decompress(j_decompress_ptr cinfo);
1126 
1127 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1128  * flavor of JPEG object.  These may be more convenient in some places.
1129  */
1130 void jpeg_abort(j_common_ptr cinfo);
1131 void jpeg_destroy(j_common_ptr cinfo);
1132 
1133 /* Default restart-marker-resync procedure for use by data source modules */
1134 boolean jpeg_resync_to_restart(j_decompress_ptr cinfo,
1135 					    int desired);
1136 
1137 
1138 /* These marker codes are exported since applications and data source modules
1139  * are likely to want to use them.
1140  */
1141 
1142 enum JPEG_RST0	= 0xD0;	/* RST0 marker code */
1143 enum JPEG_EOI	= 0xD9;	/* EOI marker code */
1144 enum JPEG_APP0	= 0xE0;	/* APP0 marker code */
1145 enum JPEG_COM	= 0xFE;	/* COM marker code */
1146 
1147 
1148 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1149  * for structure definitions that are never filled in, keep it quiet by
1150  * supplying dummy definitions for the various substructures.
1151  */
1152 
1153 struct jvirt_sarray_control { }
1154 struct jvirt_barray_control { }
1155 struct jpeg_comp_master { }
1156 struct jpeg_c_main_controller { }
1157 struct jpeg_c_prep_controller { }
1158 struct jpeg_c_coef_controller { }
1159 struct jpeg_marker_writer { }
1160 struct jpeg_color_converter { }
1161 struct jpeg_downsampler { }
1162 struct jpeg_forward_dct { }
1163 struct jpeg_entropy_encoder { }
1164 struct jpeg_decomp_master { }
1165 struct jpeg_d_main_controller { }
1166 struct jpeg_d_coef_controller { }
1167 struct jpeg_d_post_controller { }
1168 struct jpeg_input_controller { }
1169 struct jpeg_marker_reader { }
1170 struct jpeg_entropy_decoder { }
1171 struct jpeg_inverse_dct { }
1172 struct jpeg_upsampler { }
1173 struct jpeg_color_deconverter { }
1174 struct jpeg_color_quantizer { }
1175 
1176 
1177 /*
1178  * The JPEG library modules define JPEG_INTERNALS before including this file.
1179  * The internal structure declarations are read only when that is true.
1180  * Applications using the library should not include jpegint.h, but may wish
1181  * to include jerror.h.
1182  */
1183