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 
60 typedef unsigned char JSAMPLE;
61 #define GETJSAMPLE(value)  ((int) (value))
62 
63 #else /* not HAVE_UNSIGNED_CHAR */
64 
65 typedef 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 
85 typedef 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 
100 typedef 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 
111 typedef unsigned char JOCTET;
112 #define GETJOCTET(value)  (value)
113 
114 #else /* not HAVE_UNSIGNED_CHAR */
115 
116 typedef 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
136 typedef unsigned char UINT8;
137 #else /* not HAVE_UNSIGNED_CHAR */
138 #ifdef CHAR_IS_UNSIGNED
139 typedef char UINT8;
140 #else /* not CHAR_IS_UNSIGNED */
141 typedef 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
148 typedef unsigned short UINT16;
149 #else /* not HAVE_UNSIGNED_SHORT */
150 typedef 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 */
156 typedef 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 */
165 typedef 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 
178 typedef 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
229 typedef 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
263 typedef 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