libjpeg (9.5.0)
1 /*
2 * jmorecfg.h
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * Modified 1997-2013 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 contains additional configuration options that customize the
10 * JPEG software for special applications or support machine-dependent
11 * optimizations. Most users will not need to touch this file.
12 */
13
14
15 /*
16 * Define BITS_IN_JSAMPLE as either
17 * 8 for 8-bit sample values (the usual setting)
18 * 9 for 9-bit sample values
19 * 10 for 10-bit sample values
20 * 11 for 11-bit sample values
21 * 12 for 12-bit sample values
22 * Only 8, 9, 10, 11, and 12 bits sample data precision are supported for
23 * full-feature DCT processing. Further depths up to 16-bit may be added
24 * later for the lossless modes of operation.
25 * Run-time selection and conversion of data precision will be added later
26 * and are currently not supported, sorry.
27 * Exception: The transcoding part (jpegtran) supports all settings in a
28 * single instance, since it operates on the level of DCT coefficients and
29 * not sample values. The DCT coefficients are of the same type (16 bits)
30 * in all cases (see below).
31 */
32
33 #define BITS_IN_JSAMPLE 8 /* use 8, 9, 10, 11, or 12 */
34
35
36 /*
37 * Maximum number of components (color channels) allowed in JPEG image.
38 * To meet the letter of the JPEG spec, set this to 255. However, darn
39 * few applications need more than 4 channels (maybe 5 for CMYK + alpha
40 * mask). We recommend 10 as a reasonable compromise; use 4 if you are
41 * really short on memory. (Each allowed component costs a hundred or so
42 * bytes of storage, whether actually used in an image or not.)
43 */
44
45 #define MAX_COMPONENTS 10 /* maximum number of image components */
46
47
48 /*
49 * Basic data types.
50 * You may need to change these if you have a machine with unusual data
51 * type sizes; for example, "char" not 8 bits, "short" not 16 bits,
52 * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits,
53 * but it had better be at least 16.
54 */
55
56 /* Representation of a single sample (pixel element value).
57 * We frequently allocate large arrays of these, so it's important to keep
58 * them small. But if you have memory to burn and access to char or short
59 * arrays is very slow on your hardware, you might want to change these.
60 */
61
62 #if BITS_IN_JSAMPLE == 8
63 /* JSAMPLE should be the smallest type that will hold the values 0..255.
64 * You can use a signed char by having GETJSAMPLE mask it with 0xFF.
65 */
66
67 #ifdef HAVE_UNSIGNED_CHAR
68
69 typedef unsigned char JSAMPLE;
70 #define GETJSAMPLE(value) ((int) (value))
71
72 #else /* not HAVE_UNSIGNED_CHAR */
73
74 typedef char JSAMPLE;
75 #ifdef CHAR_IS_UNSIGNED
76 #define GETJSAMPLE(value) ((int) (value))
77 #else
78 #define GETJSAMPLE(value) ((int) (value) & 0xFF)
79 #endif /* CHAR_IS_UNSIGNED */
80
81 #endif /* HAVE_UNSIGNED_CHAR */
82
83 #define MAXJSAMPLE 255
84 #define CENTERJSAMPLE 128
85
86 #endif /* BITS_IN_JSAMPLE == 8 */
87
88
89 #if BITS_IN_JSAMPLE == 9
90 /* JSAMPLE should be the smallest type that will hold the values 0..511.
91 * On nearly all machines "short" will do nicely.
92 */
93
94 typedef short JSAMPLE;
95 #define GETJSAMPLE(value) ((int) (value))
96
97 #define MAXJSAMPLE 511
98 #define CENTERJSAMPLE 256
99
100 #endif /* BITS_IN_JSAMPLE == 9 */
101
102
103 #if BITS_IN_JSAMPLE == 10
104 /* JSAMPLE should be the smallest type that will hold the values 0..1023.
105 * On nearly all machines "short" will do nicely.
106 */
107
108 typedef short JSAMPLE;
109 #define GETJSAMPLE(value) ((int) (value))
110
111 #define MAXJSAMPLE 1023
112 #define CENTERJSAMPLE 512
113
114 #endif /* BITS_IN_JSAMPLE == 10 */
115
116
117 #if BITS_IN_JSAMPLE == 11
118 /* JSAMPLE should be the smallest type that will hold the values 0..2047.
119 * On nearly all machines "short" will do nicely.
120 */
121
122 typedef short JSAMPLE;
123 #define GETJSAMPLE(value) ((int) (value))
124
125 #define MAXJSAMPLE 2047
126 #define CENTERJSAMPLE 1024
127
128 #endif /* BITS_IN_JSAMPLE == 11 */
129
130
131 #if BITS_IN_JSAMPLE == 12
132 /* JSAMPLE should be the smallest type that will hold the values 0..4095.
133 * On nearly all machines "short" will do nicely.
134 */
135
136 typedef short JSAMPLE;
137 #define GETJSAMPLE(value) ((int) (value))
138
139 #define MAXJSAMPLE 4095
140 #define CENTERJSAMPLE 2048
141
142 #endif /* BITS_IN_JSAMPLE == 12 */
143
144
145 /* Representation of a DCT frequency coefficient.
146 * This should be a signed value of at least 16 bits; "short" is usually OK.
147 * Again, we allocate large arrays of these, but you can change to int
148 * if you have memory to burn and "short" is really slow.
149 */
150
151 typedef short JCOEF;
152
153
154 /* Compressed datastreams are represented as arrays of JOCTET.
155 * These must be EXACTLY 8 bits wide, at least once they are written to
156 * external storage. Note that when using the stdio data source/destination
157 * managers, this is also the data type passed to fread/fwrite.
158 */
159
160 #ifdef HAVE_UNSIGNED_CHAR
161
162 typedef unsigned char JOCTET;
163 #define GETJOCTET(value) (value)
164
165 #else /* not HAVE_UNSIGNED_CHAR */
166
167 typedef char JOCTET;
168 #ifdef CHAR_IS_UNSIGNED
169 #define GETJOCTET(value) (value)
170 #else
171 #define GETJOCTET(value) ((value) & 0xFF)
172 #endif /* CHAR_IS_UNSIGNED */
173
174 #endif /* HAVE_UNSIGNED_CHAR */
175
176
177 /* These typedefs are used for various table entries and so forth.
178 * They must be at least as wide as specified; but making them too big
179 * won't cost a huge amount of memory, so we don't provide special
180 * extraction code like we did for JSAMPLE. (In other words, these
181 * typedefs live at a different point on the speed/space tradeoff curve.)
182 */
183
184 /* UINT8 must hold at least the values 0..255. */
185
186 #ifdef HAVE_UNSIGNED_CHAR
187 typedef unsigned char UINT8;
188 #else /* not HAVE_UNSIGNED_CHAR */
189 #ifdef CHAR_IS_UNSIGNED
190 typedef char UINT8;
191 #else /* not CHAR_IS_UNSIGNED */
192 typedef short UINT8;
193 #endif /* CHAR_IS_UNSIGNED */
194 #endif /* HAVE_UNSIGNED_CHAR */
195
196 /* UINT16 must hold at least the values 0..65535. */
197
198 #ifdef HAVE_UNSIGNED_SHORT
199 typedef unsigned short UINT16;
200 #else /* not HAVE_UNSIGNED_SHORT */
201 typedef unsigned int UINT16;
202 #endif /* HAVE_UNSIGNED_SHORT */
203
204 /* INT16 must hold at least the values -32768..32767. */
205
206 #ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
207 typedef short INT16;
208 #endif
209
210 /* INT32 must hold at least signed 32-bit values. */
211
212 #ifndef XMD_H /* X11/xmd.h correctly defines INT32 */
213 #ifndef _BASETSD_H_ /* Microsoft defines it in basetsd.h */
214 #ifndef _BASETSD_H /* MinGW is slightly different */
215 #ifndef QGLOBAL_H /* Qt defines it in qglobal.h */
216 typedef long INT32;
217 #endif
218 #endif
219 #endif
220 #endif
221
222 /* Datatype used for image dimensions. The JPEG standard only supports
223 * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
224 * "unsigned int" is sufficient on all machines. However, if you need to
225 * handle larger images and you don't mind deviating from the spec, you
226 * can change this datatype.
227 */
228
229 typedef unsigned int JDIMENSION;
230
231 #define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
232
233
234 /* These macros are used in all function definitions and extern declarations.
235 * You could modify them if you need to change function linkage conventions;
236 * in particular, you'll need to do that to make the library a Windows DLL.
237 * Another application is to make all functions global for use with debuggers
238 * or code profilers that require it.
239 */
240
241 /* a function called through method pointers: */
242 #define METHODDEF(type) static type
243 /* a function used only in its module: */
244 #define LOCAL(type) static type
245 /* a function referenced thru EXTERNs: */
246 #define GLOBAL(type) type
247 /* a reference to a GLOBAL function: */
248 #define EXTERN(type) extern type
249
250
251 /* This macro is used to declare a "method", that is, a function pointer.
252 * We want to supply prototype parameters if the compiler can cope.
253 * Note that the arglist parameter must be parenthesized!
254 * Again, you can customize this if you need special linkage keywords.
255 */
256
257 #ifdef HAVE_PROTOTYPES
258 #define JMETHOD(type,methodname,arglist) type (*methodname) arglist
259 #else
260 #define JMETHOD(type,methodname,arglist) type (*methodname) ()
261 #endif
262
263
264 /* The noreturn type identifier is used to declare functions
265 * which cannot return.
266 * Compilers can thus create more optimized code and perform
267 * better checks for warnings and errors.
268 * Static analyzer tools can make improved inferences about
269 * execution paths and are prevented from giving false alerts.
270 *
271 * Unfortunately, the proposed specifications of corresponding
272 * extensions in the Dec 2011 ISO C standard revision (C11),
273 * GCC, MSVC, etc. are not viable.
274 * Thus we introduce a user defined type to declare noreturn
275 * functions at least for clarity. A proper compiler would
276 * have a suitable noreturn type to match in place of void.
277 */
278
279 #ifndef HAVE_NORETURN_T
280 typedef void noreturn_t;
281 #endif
282
283
284 /* Here is the pseudo-keyword for declaring pointers that must be "far"
285 * on 80x86 machines. Most of the specialized coding for 80x86 is handled
286 * by just saying "FAR *" where such a pointer is needed. In a few places
287 * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
288 */
289
290 #ifndef FAR
291 #ifdef NEED_FAR_POINTERS
292 #define FAR far
293 #else
294 #define FAR
295 #endif
296 #endif
297
298
299 /*
300 * On a few systems, type boolean and/or its values FALSE, TRUE may appear
301 * in standard header files. Or you may have conflicts with application-
302 * specific header files that you want to include together with these files.
303 * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
304 */
305
306 #ifndef HAVE_BOOLEAN
307 #if defined FALSE || defined TRUE || defined QGLOBAL_H
308 /* Qt3 defines FALSE and TRUE as "const" variables in qglobal.h */
309 typedef int boolean;
310 #ifndef FALSE /* in case these macros already exist */
311 #define FALSE 0 /* values of boolean */
312 #endif
313 #ifndef TRUE
314 #define TRUE 1
315 #endif
316 #else
317 typedef enum { FALSE = 0, TRUE = 1 } boolean;
318 #endif
319 #endif
320
321
322 /*
323 * The remaining options affect code selection within the JPEG library,
324 * but they don't need to be visible to most applications using the library.
325 * To minimize application namespace pollution, the symbols won't be
326 * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
327 */
328
329 #ifdef JPEG_INTERNALS
330 #define JPEG_INTERNAL_OPTIONS
331 #endif
332
333 #ifdef JPEG_INTERNAL_OPTIONS
334
335
336 /*
337 * These defines indicate whether to include various optional functions.
338 * Undefining some of these symbols will produce a smaller but less capable
339 * library. Note that you can leave certain source files out of the
340 * compilation/linking process if you've #undef'd the corresponding symbols.
341 * (You may HAVE to do that if your compiler doesn't like null source files.)
342 */
343
344 /* Capability options common to encoder and decoder: */
345
346 #define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
347 #define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
348 #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
349
350 /* Encoder capability options: */
351
352 #define C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
353 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
354 #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
355 #define DCT_SCALING_SUPPORTED /* Input rescaling via DCT? (Requires DCT_ISLOW)*/
356 #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
357 /* Note: if you selected more than 8-bit data precision, it is dangerous to
358 * turn off ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only
359 * good for 8-bit precision, so arithmetic coding is recommended for higher
360 * precision. The Huffman encoder normally uses entropy optimization to
361 * compute usable tables for higher precision. Otherwise, you'll have to
362 * supply different default Huffman tables.
363 * The exact same statements apply for progressive JPEG: the default tables
364 * don't work for progressive mode. (This may get fixed, however.)
365 */
366 #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
367
368 /* Decoder capability options: */
369
370 #define D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
371 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
372 #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
373 #define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? (Requires DCT_ISLOW)*/
374 #define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
375 #define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
376 #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
377 #define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
378 #define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
379 #define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
380
381 /* more capability options later, no doubt */
382
383
384 /*
385 * Ordering of RGB data in scanlines passed to or from the application.
386 * If your application wants to deal with data in the order B,G,R, just
387 * change these macros. You can also deal with formats such as R,G,B,X
388 * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
389 * the offsets will also change the order in which colormap data is organized.
390 * RESTRICTIONS:
391 * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
392 * 2. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
393 * is not 3 (they don't understand about dummy color components!). So you
394 * can't use color quantization if you change that value.
395 */
396
397 #define RGB_RED 0 /* Offset of Red in an RGB scanline element */
398 #define RGB_GREEN 1 /* Offset of Green */
399 #define RGB_BLUE 2 /* Offset of Blue */
400 #define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */
401
402
403 /* Definitions for speed-related optimizations. */
404
405
406 /* If your compiler supports inline functions, define INLINE
407 * as the inline keyword; otherwise define it as empty.
408 */
409
410 #ifndef INLINE
411 #ifdef __GNUC__ /* for instance, GNU C knows about inline */
412 #define INLINE __inline__
413 #endif
414 #ifndef INLINE
415 #define INLINE /* default is to define it as empty */
416 #endif
417 #endif
418
419
420 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
421 * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
422 * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
423 */
424
425 #ifndef MULTIPLIER
426 #define MULTIPLIER int /* type for fastest integer multiply */
427 #endif
428
429
430 /* FAST_FLOAT should be either float or double, whichever is done faster
431 * by your compiler. (Note that this type is only used in the floating point
432 * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
433 * Typically, float is faster in ANSI C compilers, while double is faster in
434 * pre-ANSI compilers (because they insist on converting to double anyway).
435 * The code below therefore chooses float if we have ANSI-style prototypes.
436 */
437
438 #ifndef FAST_FLOAT
439 #ifdef HAVE_PROTOTYPES
440 #define FAST_FLOAT float
441 #else
442 #define FAST_FLOAT double
443 #endif
444 #endif
445
446 #endif /* JPEG_INTERNAL_OPTIONS */
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