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jmorecfg.h
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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 #ifdef _WIN32
242 # if defined(ALL_STATIC)
243 # if defined(JPEG_DLL)
244 # undef JPEG_DLL
245 # endif
246 # if !defined(JPEG_STATIC)
247 # define JPEG_STATIC
248 # endif
249 # endif
250 # if defined(JPEG_DLL)
251 # if defined(JPEG_STATIC)
252 # undef JPEG_STATIC
253 # endif
254 # endif
255 # if defined(JPEG_DLL)
256 /* building a DLL */
257 # define JPEG_IMPEXP __declspec(dllexport)
258 # elif defined(JPEG_STATIC)
259 /* building or linking to a static library */
260 # define JPEG_IMPEXP
261 # else
262 /* linking to the DLL */
263 # define JPEG_IMPEXP __declspec(dllimport)
264 # endif
265 # if !defined(JPEG_API)
266 # define JPEG_API __cdecl
267 # endif
268 /* The only remaining magic that is necessary for cygwin */
269 #elif defined(__CYGWIN__)
270 # if !defined(JPEG_IMPEXP)
271 # define JPEG_IMPEXP
272 # endif
273 # if !defined(JPEG_API)
274 # define JPEG_API __cdecl
275 # endif
276 #endif
277 
278 /* Ensure our magic doesn't hurt other platforms */
279 #if !defined(JPEG_IMPEXP)
280 # define JPEG_IMPEXP
281 #endif
282 #if !defined(JPEG_API)
283 # define JPEG_API
284 #endif
285 
286 /* a function called through method pointers: */
287 #define METHODDEF(type) static type
288 /* a function used only in its module: */
289 #define LOCAL(type) static type
290 /* a function referenced thru EXTERNs: */
291 #define GLOBAL(type) type JPEG_API
292 /* a reference to a GLOBAL function: */
293 #ifndef EXTERN
294 # define EXTERN(type) extern JPEG_IMPEXP type JPEG_API
295 /* a reference to a "GLOBAL" function exported by sourcefiles of utility progs */
296 #endif /* EXTERN */
297 
298 
299 /* This macro is used to declare a "method", that is, a function pointer.
300  * We want to supply prototype parameters if the compiler can cope.
301  * Note that the arglist parameter must be parenthesized!
302  * Again, you can customize this if you need special linkage keywords.
303  */
304 
305 #ifdef HAVE_PROTOTYPES
306 #define JMETHOD(type,methodname,arglist) type (*methodname) arglist
307 #else
308 #define JMETHOD(type,methodname,arglist) type (*methodname) ()
309 #endif
310 
311 
312 /* The noreturn type identifier is used to declare functions
313  * which cannot return.
314  * Compilers can thus create more optimized code and perform
315  * better checks for warnings and errors.
316  * Static analyzer tools can make improved inferences about
317  * execution paths and are prevented from giving false alerts.
318  *
319  * Unfortunately, the proposed specifications of corresponding
320  * extensions in the Dec 2011 ISO C standard revision (C11),
321  * GCC, MSVC, etc. are not viable.
322  * Thus we introduce a user defined type to declare noreturn
323  * functions at least for clarity. A proper compiler would
324  * have a suitable noreturn type to match in place of void.
325  */
326 
327 #ifndef HAVE_NORETURN_T
328 typedef void noreturn_t;
329 #endif
330 
331 
332 /* Here is the pseudo-keyword for declaring pointers that must be "far"
333  * on 80x86 machines. Most of the specialized coding for 80x86 is handled
334  * by just saying "FAR *" where such a pointer is needed. In a few places
335  * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
336  */
337 
338 #ifndef FAR
339 #ifdef NEED_FAR_POINTERS
340 #define FAR far
341 #else
342 #define FAR
343 #endif
344 #endif
345 
346 
347 /*
348  * On a few systems, type boolean and/or its values FALSE, TRUE may appear
349  * in standard header files. Or you may have conflicts with application-
350  * specific header files that you want to include together with these files.
351  * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
352  */
353 
354 #ifndef HAVE_BOOLEAN
355 #if defined FALSE || defined TRUE || defined QGLOBAL_H
356 /* Qt3 defines FALSE and TRUE as "const" variables in qglobal.h */
357 typedef int boolean;
358 #ifndef FALSE /* in case these macros already exist */
359 #define FALSE 0 /* values of boolean */
360 #endif
361 #ifndef TRUE
362 #define TRUE 1
363 #endif
364 #else
365 typedef enum { FALSE = 0, TRUE = 1 } boolean;
366 #endif
367 #endif
368 
369 
370 /*
371  * The remaining options affect code selection within the JPEG library,
372  * but they don't need to be visible to most applications using the library.
373  * To minimize application namespace pollution, the symbols won't be
374  * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
375  */
376 
377 #ifdef JPEG_INTERNALS
378 #define JPEG_INTERNAL_OPTIONS
379 #endif
380 
381 #ifdef JPEG_INTERNAL_OPTIONS
382 
383 
384 /*
385  * These defines indicate whether to include various optional functions.
386  * Undefining some of these symbols will produce a smaller but less capable
387  * library. Note that you can leave certain source files out of the
388  * compilation/linking process if you've #undef'd the corresponding symbols.
389  * (You may HAVE to do that if your compiler doesn't like null source files.)
390  */
391 
392 /* Capability options common to encoder and decoder: */
393 
394 #define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
395 #define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
396 #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
397 
398 /* Encoder capability options: */
399 
400 #define C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
401 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
402 #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
403 #define DCT_SCALING_SUPPORTED /* Input rescaling via DCT? (Requires DCT_ISLOW)*/
404 #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
405 /* Note: if you selected more than 8-bit data precision, it is dangerous to
406  * turn off ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only
407  * good for 8-bit precision, so arithmetic coding is recommended for higher
408  * precision. The Huffman encoder normally uses entropy optimization to
409  * compute usable tables for higher precision. Otherwise, you'll have to
410  * supply different default Huffman tables.
411  * The exact same statements apply for progressive JPEG: the default tables
412  * don't work for progressive mode. (This may get fixed, however.)
413  */
414 #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
415 
416 /* Decoder capability options: */
417 
418 #define D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
419 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
420 #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
421 #define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? (Requires DCT_ISLOW)*/
422 #define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
423 #define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
424 #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
425 #define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
426 #define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
427 #define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
428 
429 /* more capability options later, no doubt */
430 
431 
432 /*
433  * Ordering of RGB data in scanlines passed to or from the application.
434  * If your application wants to deal with data in the order B,G,R, just
435  * change these macros. You can also deal with formats such as R,G,B,X
436  * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
437  * the offsets will also change the order in which colormap data is organized.
438  * RESTRICTIONS:
439  * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
440  * 2. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
441  * is not 3 (they don't understand about dummy color components!). So you
442  * can't use color quantization if you change that value.
443  */
444 
445 #define RGB_RED 0 /* Offset of Red in an RGB scanline element */
446 #define RGB_GREEN 1 /* Offset of Green */
447 #define RGB_BLUE 2 /* Offset of Blue */
448 #define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */
449 
450 
451 /* Definitions for speed-related optimizations. */
452 
453 
454 /* If your compiler supports inline functions, define INLINE
455  * as the inline keyword; otherwise define it as empty.
456  */
457 
458 #ifndef INLINE
459 #ifdef __GNUC__ /* for instance, GNU C knows about inline */
460 #define INLINE __inline__
461 #endif
462 #ifndef INLINE
463 #define INLINE /* default is to define it as empty */
464 #endif
465 #endif
466 
467 
468 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
469  * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
470  * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
471  */
472 
473 #ifndef MULTIPLIER
474 #define MULTIPLIER int /* type for fastest integer multiply */
475 #endif
476 
477 
478 /* FAST_FLOAT should be either float or double, whichever is done faster
479  * by your compiler. (Note that this type is only used in the floating point
480  * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
481  * Typically, float is faster in ANSI C compilers, while double is faster in
482  * pre-ANSI compilers (because they insist on converting to double anyway).
483  * The code below therefore chooses float if we have ANSI-style prototypes.
484  */
485 
486 #ifndef FAST_FLOAT
487 #ifdef HAVE_PROTOTYPES
488 #define FAST_FLOAT float
489 #else
490 #define FAST_FLOAT double
491 #endif
492 #endif
493 
494 #endif /* JPEG_INTERNAL_OPTIONS */
char JSAMPLE
Definition: jmorecfg.h:74
short INT16
Definition: jmorecfg.h:207
short JCOEF
Definition: jmorecfg.h:151
long INT32
Definition: jmorecfg.h:216
short UINT8
Definition: jmorecfg.h:192
void noreturn_t
Definition: jmorecfg.h:328
unsigned int UINT16
Definition: jmorecfg.h:201
unsigned int JDIMENSION
Definition: jmorecfg.h:229
Definition: jmorecfg.h:365
char JOCTET
Definition: jmorecfg.h:167
boolean
Definition: jmorecfg.h:365