1/*
2 * jmorecfg.h
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * Modified 1997-2012 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 * 12 for 12-bit sample values
19 * Only 8 and 12 are legal data precisions for lossy JPEG according to the
20 * JPEG standard, and the IJG code does not support anything else!
21 * We do not support run-time selection of data precision, sorry.
22 */
23
24#define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
25
26
27/*
28 * Maximum number of components (color channels) allowed in JPEG image.
29 * To meet the letter of the JPEG spec, set this to 255. However, darn
30 * few applications need more than 4 channels (maybe 5 for CMYK + alpha
31 * mask). We recommend 10 as a reasonable compromise; use 4 if you are
32 * really short on memory. (Each allowed component costs a hundred or so
33 * bytes of storage, whether actually used in an image or not.)
34 */
35
36#define MAX_COMPONENTS 10 /* maximum number of image components */
37
38
39/*
40 * Basic data types.
41 * You may need to change these if you have a machine with unusual data
42 * type sizes; for example, "char" not 8 bits, "short" not 16 bits,
43 * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits,
44 * but it had better be at least 16.
45 */
46
47/* Representation of a single sample (pixel element value).
48 * We frequently allocate large arrays of these, so it's important to keep
49 * them small. But if you have memory to burn and access to char or short
50 * arrays is very slow on your hardware, you might want to change these.
51 */
52
53#if BITS_IN_JSAMPLE == 8
54/* JSAMPLE should be the smallest type that will hold the values 0..255.
55 * You can use a signed char by having GETJSAMPLE mask it with 0xFF.
56 */
57
58#ifdef HAVE_UNSIGNED_CHAR
59
60typedef unsigned char JSAMPLE;
61#define GETJSAMPLE(value) ((int) (value))
62
63#else /* not HAVE_UNSIGNED_CHAR */
64
65typedef char JSAMPLE;
66#ifdef CHAR_IS_UNSIGNED
67#define GETJSAMPLE(value) ((int) (value))
68#else
69#define GETJSAMPLE(value) ((int) (value) & 0xFF)
70#endif /* CHAR_IS_UNSIGNED */
71
72#endif /* HAVE_UNSIGNED_CHAR */
73
74#define MAXJSAMPLE 255
75#define CENTERJSAMPLE 128
76
77#endif /* BITS_IN_JSAMPLE == 8 */
78
79
80#if BITS_IN_JSAMPLE == 12
81/* JSAMPLE should be the smallest type that will hold the values 0..4095.
82 * On nearly all machines "short" will do nicely.
83 */
84
85typedef short JSAMPLE;
86#define GETJSAMPLE(value) ((int) (value))
87
88#define MAXJSAMPLE 4095
89#define CENTERJSAMPLE 2048
90
91#endif /* BITS_IN_JSAMPLE == 12 */
92
93
94/* Representation of a DCT frequency coefficient.
95 * This should be a signed value of at least 16 bits; "short" is usually OK.
96 * Again, we allocate large arrays of these, but you can change to int
97 * if you have memory to burn and "short" is really slow.
98 */
99
100typedef short JCOEF;
101
102
103/* Compressed datastreams are represented as arrays of JOCTET.
104 * These must be EXACTLY 8 bits wide, at least once they are written to
105 * external storage. Note that when using the stdio data source/destination
106 * managers, this is also the data type passed to fread/fwrite.
107 */
108
109#ifdef HAVE_UNSIGNED_CHAR
110
111typedef unsigned char JOCTET;
112#define GETJOCTET(value) (value)
113
114#else /* not HAVE_UNSIGNED_CHAR */
115
116typedef char JOCTET;
117#ifdef CHAR_IS_UNSIGNED
118#define GETJOCTET(value) (value)
119#else
120#define GETJOCTET(value) ((value) & 0xFF)
121#endif /* CHAR_IS_UNSIGNED */
122
123#endif /* HAVE_UNSIGNED_CHAR */
124
125
126/* These typedefs are used for various table entries and so forth.
127 * They must be at least as wide as specified; but making them too big
128 * won't cost a huge amount of memory, so we don't provide special
129 * extraction code like we did for JSAMPLE. (In other words, these
130 * typedefs live at a different point on the speed/space tradeoff curve.)
131 */
132
133/* UINT8 must hold at least the values 0..255. */
134
135#ifdef HAVE_UNSIGNED_CHAR
136typedef unsigned char UINT8;
137#else /* not HAVE_UNSIGNED_CHAR */
138#ifdef CHAR_IS_UNSIGNED
139typedef char UINT8;
140#else /* not CHAR_IS_UNSIGNED */
141typedef short UINT8;
142#endif /* CHAR_IS_UNSIGNED */
143#endif /* HAVE_UNSIGNED_CHAR */
144
145/* UINT16 must hold at least the values 0..65535. */
146
147#ifdef HAVE_UNSIGNED_SHORT
148typedef unsigned short UINT16;
149#else /* not HAVE_UNSIGNED_SHORT */
150typedef unsigned int UINT16;
151#endif /* HAVE_UNSIGNED_SHORT */
152
153/* INT16 must hold at least the values -32768..32767. */
154
155#ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
156typedef short INT16;
157#endif
158
159/* INT32 must hold at least signed 32-bit values. */
160
161#ifndef XMD_H /* X11/xmd.h correctly defines INT32 */
162#ifndef _BASETSD_H_ /* Microsoft defines it in basetsd.h */
163#ifndef _BASETSD_H /* MinGW is slightly different */
164#ifndef QGLOBAL_H /* Qt defines it in qglobal.h */
165typedef long INT32;
166#endif
167#endif
168#endif
169#endif
170
171/* Datatype used for image dimensions. The JPEG standard only supports
172 * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
173 * "unsigned int" is sufficient on all machines. However, if you need to
174 * handle larger images and you don't mind deviating from the spec, you
175 * can change this datatype.
176 */
177
178typedef unsigned int JDIMENSION;
179
180#define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
181
182
183/* These macros are used in all function definitions and extern declarations.
184 * You could modify them if you need to change function linkage conventions;
185 * in particular, you'll need to do that to make the library a Windows DLL.
186 * Another application is to make all functions global for use with debuggers
187 * or code profilers that require it.
188 */
189
190/* a function called through method pointers: */
191#define METHODDEF(type) static type
192/* a function used only in its module: */
193#define LOCAL(type) static type
194/* a function referenced thru EXTERNs: */
195#define GLOBAL(type) type
196/* a reference to a GLOBAL function: */
197#define EXTERN(type) extern type
198
199
200/* This macro is used to declare a "method", that is, a function pointer.
201 * We want to supply prototype parameters if the compiler can cope.
202 * Note that the arglist parameter must be parenthesized!
203 * Again, you can customize this if you need special linkage keywords.
204 */
205
206#ifdef HAVE_PROTOTYPES
207#define JMETHOD(type,methodname,arglist) type (*methodname) arglist
208#else
209#define JMETHOD(type,methodname,arglist) type (*methodname) ()
210#endif
211
212
213/* The noreturn type identifier is used to declare functions
214 * which cannot return.
215 * Compilers can thus create more optimized code and perform
216 * better checks for warnings and errors.
217 * Static analyzer tools can make improved inferences about
218 * execution paths and are prevented from giving false alerts.
219 *
220 * Unfortunately, the proposed specifications of corresponding
221 * extensions in the Dec 2011 ISO C standard revision (C11),
222 * GCC, MSVC, etc. are not viable.
223 * Thus we introduce a user defined type to declare noreturn
224 * functions at least for clarity. A proper compiler would
225 * have a suitable noreturn type to match in place of void.
226 */
227
228#ifndef HAVE_NORETURN_T
229typedef void noreturn_t;
230#endif
231
232
233/* Here is the pseudo-keyword for declaring pointers that must be "far"
234 * on 80x86 machines. Most of the specialized coding for 80x86 is handled
235 * by just saying "FAR *" where such a pointer is needed. In a few places
236 * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
237 */
238
239#ifndef FAR
240#ifdef NEED_FAR_POINTERS
241#define FAR far
242#else
243#define FAR
244#endif
245#endif
246
247
248/*
249 * On a few systems, type boolean and/or its values FALSE, TRUE may appear
250 * in standard header files. Or you may have conflicts with application-
251 * specific header files that you want to include together with these files.
252 * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
253 */
254
255#ifdef HAVE_BOOLEAN
256#ifndef FALSE /* in case these macros already exist */
257#define FALSE 0 /* values of boolean */
258#endif
259#ifndef TRUE
260#define TRUE 1
261#endif
262#else
263typedef enum { FALSE = 0, TRUE = 1 } boolean;
264#endif
265
266
267/*
268 * The remaining options affect code selection within the JPEG library,
269 * but they don't need to be visible to most applications using the library.
270 * To minimize application namespace pollution, the symbols won't be
271 * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
272 */
273
274#ifdef JPEG_INTERNALS
275#define JPEG_INTERNAL_OPTIONS
276#endif
277
278#ifdef JPEG_INTERNAL_OPTIONS
279
280
281/*
282 * These defines indicate whether to include various optional functions.
283 * Undefining some of these symbols will produce a smaller but less capable
284 * library. Note that you can leave certain source files out of the
285 * compilation/linking process if you've #undef'd the corresponding symbols.
286 * (You may HAVE to do that if your compiler doesn't like null source files.)
287 */
288
289/* Capability options common to encoder and decoder: */
290
291#define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
292#define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
293#define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
294
295/* Encoder capability options: */
296
297#define C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
298#define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
299#define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
300#define DCT_SCALING_SUPPORTED /* Input rescaling via DCT? (Requires DCT_ISLOW)*/
301#define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
302/* Note: if you selected 12-bit data precision, it is dangerous to turn off
303 * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit
304 * precision, so jchuff.c normally uses entropy optimization to compute
305 * usable tables for higher precision. If you don't want to do optimization,
306 * you'll have to supply different default Huffman tables.
307 * The exact same statements apply for progressive JPEG: the default tables
308 * don't work for progressive mode. (This may get fixed, however.)
309 */
310#define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
311
312/* Decoder capability options: */
313
314#define D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
315#define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
316#define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
317#define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */
318#define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
319#define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
320#undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
321#define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
322#define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
323#define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
324
325/* more capability options later, no doubt */
326
327
328/*
329 * Ordering of RGB data in scanlines passed to or from the application.
330 * If your application wants to deal with data in the order B,G,R, just
331 * change these macros. You can also deal with formats such as R,G,B,X
332 * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
333 * the offsets will also change the order in which colormap data is organized.
334 * RESTRICTIONS:
335 * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
336 * 2. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
337 * is not 3 (they don't understand about dummy color components!). So you
338 * can't use color quantization if you change that value.
339 */
340
341#define RGB_RED 0 /* Offset of Red in an RGB scanline element */
342#define RGB_GREEN 1 /* Offset of Green */
343#define RGB_BLUE 2 /* Offset of Blue */
344#define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */
345
346
347/* Definitions for speed-related optimizations. */
348
349
350/* If your compiler supports inline functions, define INLINE
351 * as the inline keyword; otherwise define it as empty.
352 */
353
354#ifndef INLINE
355#ifdef __GNUC__ /* for instance, GNU C knows about inline */
356#define INLINE __inline__
357#endif
358#ifndef INLINE
359#define INLINE /* default is to define it as empty */
360#endif
361#endif
362
363
364/* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
365 * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
366 * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
367 */
368
369#ifndef MULTIPLIER
370#define MULTIPLIER int /* type for fastest integer multiply */
371#endif
372
373
374/* FAST_FLOAT should be either float or double, whichever is done faster
375 * by your compiler. (Note that this type is only used in the floating point
376 * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
377 * Typically, float is faster in ANSI C compilers, while double is faster in
378 * pre-ANSI compilers (because they insist on converting to double anyway).
379 * The code below therefore chooses float if we have ANSI-style prototypes.
380 */
381
382#ifndef FAST_FLOAT
383#ifdef HAVE_PROTOTYPES
384#define FAST_FLOAT float
385#else
386#define FAST_FLOAT double
387#endif
388#endif
389
390#endif /* JPEG_INTERNAL_OPTIONS */
391