4 * Copyright (C) 1991-1995, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
8 * This file contains additional configuration options that customize the
9 * JPEG software for special applications or support machine-dependent
10 * optimizations. Most users will not need to touch this file.
15 * Define BITS_IN_JSAMPLE as either
16 * 8 for 8-bit sample values (the usual setting)
17 * 12 for 12-bit sample values
18 * Only 8 and 12 are legal data precisions for lossy JPEG according to the
19 * JPEG standard, and the IJG code does not support anything else!
20 * We do not support run-time selection of data precision, sorry.
23 #define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
27 * Maximum number of components (color channels) allowed in JPEG image.
28 * To meet the letter of the JPEG spec, set this to 255. However, darn
29 * few applications need more than 4 channels (maybe 5 for CMYK + alpha
30 * mask). We recommend 10 as a reasonable compromise; use 4 if you are
31 * really short on memory. (Each allowed component costs a hundred or so
32 * bytes of storage, whether actually used in an image or not.)
35 #define MAX_COMPONENTS 10 /* maximum number of image components */
40 * You may need to change these if you have a machine with unusual data
41 * type sizes; for example, "char" not 8 bits, "short" not 16 bits,
42 * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits,
43 * but it had better be at least 16.
46 /* Representation of a single sample (pixel element value).
47 * We frequently allocate large arrays of these, so it's important to keep
48 * them small. But if you have memory to burn and access to char or short
49 * arrays is very slow on your hardware, you might want to change these.
52 #if BITS_IN_JSAMPLE == 8
53 /* JSAMPLE should be the smallest type that will hold the values 0..255.
54 * You can use a signed char by having GETJSAMPLE mask it with 0xFF.
57 #ifdef HAVE_UNSIGNED_CHAR
59 typedef unsigned char JSAMPLE;
60 #define GETJSAMPLE(value) ((int) (value))
62 #else /* not HAVE_UNSIGNED_CHAR */
65 #ifdef CHAR_IS_UNSIGNED
66 #define GETJSAMPLE(value) ((int) (value))
68 #define GETJSAMPLE(value) ((int) (value) & 0xFF)
69 #endif /* CHAR_IS_UNSIGNED */
71 #endif /* HAVE_UNSIGNED_CHAR */
73 #define MAXJSAMPLE 255
74 #define CENTERJSAMPLE 128
76 #endif /* BITS_IN_JSAMPLE == 8 */
79 #if BITS_IN_JSAMPLE == 12
80 /* JSAMPLE should be the smallest type that will hold the values 0..4095.
81 * On nearly all machines "short" will do nicely.
84 typedef short JSAMPLE;
85 #define GETJSAMPLE(value) ((int) (value))
87 #define MAXJSAMPLE 4095
88 #define CENTERJSAMPLE 2048
90 #endif /* BITS_IN_JSAMPLE == 12 */
93 /* Representation of a DCT frequency coefficient.
94 * This should be a signed value of at least 16 bits; "short" is usually OK.
95 * Again, we allocate large arrays of these, but you can change to int
96 * if you have memory to burn and "short" is really slow.
102 /* Compressed datastreams are represented as arrays of JOCTET.
103 * These must be EXACTLY 8 bits wide, at least once they are written to
104 * external storage. Note that when using the stdio data source/destination
105 * managers, this is also the data type passed to fread/fwrite.
108 #ifdef HAVE_UNSIGNED_CHAR
110 typedef unsigned char JOCTET;
111 #define GETJOCTET(value) (value)
113 #else /* not HAVE_UNSIGNED_CHAR */
116 #ifdef CHAR_IS_UNSIGNED
117 #define GETJOCTET(value) (value)
119 #define GETJOCTET(value) ((value) & 0xFF)
120 #endif /* CHAR_IS_UNSIGNED */
122 #endif /* HAVE_UNSIGNED_CHAR */
125 /* These typedefs are used for various table entries and so forth.
126 * They must be at least as wide as specified; but making them too big
127 * won't cost a huge amount of memory, so we don't provide special
128 * extraction code like we did for JSAMPLE. (In other words, these
129 * typedefs live at a different point on the speed/space tradeoff curve.)
132 /* UINT8 must hold at least the values 0..255. */
134 #ifdef HAVE_UNSIGNED_CHAR
135 typedef unsigned char UINT8;
136 #else /* not HAVE_UNSIGNED_CHAR */
137 #ifdef CHAR_IS_UNSIGNED
139 #else /* not CHAR_IS_UNSIGNED */
141 #endif /* CHAR_IS_UNSIGNED */
142 #endif /* HAVE_UNSIGNED_CHAR */
144 /* UINT16 must hold at least the values 0..65535. */
146 #ifdef HAVE_UNSIGNED_SHORT
147 typedef unsigned short UINT16;
148 #else /* not HAVE_UNSIGNED_SHORT */
149 typedef unsigned int UINT16;
150 #endif /* HAVE_UNSIGNED_SHORT */
152 /* INT16 must hold at least the values -32768..32767. */
154 #ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
158 /* INT32 must hold at least signed 32-bit values. */
160 //#ifndef XMD_H /* X11/xmd.h correctly defines INT32 */
161 //typedef long INT32;
164 /* Datatype used for image dimensions. The JPEG standard only supports
165 * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
166 * "unsigned int" is sufficient on all machines. However, if you need to
167 * handle larger images and you don't mind deviating from the spec, you
168 * can change this datatype.
171 typedef unsigned int JDIMENSION;
173 #define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
176 /* These defines are used in all function definitions and extern declarations.
177 * You could modify them if you need to change function linkage conventions.
178 * Another application is to make all functions global for use with debuggers
179 * or code profilers that require it.
182 #define METHODDEF static /* a function called through method pointers */
183 #define LOCAL static /* a function used only in its module */
184 #define GLOBAL /* a function referenced thru EXTERNs */
185 #define EXTERN extern /* a reference to a GLOBAL function */
188 /* Here is the pseudo-keyword for declaring pointers that must be "far"
189 * on 80x86 machines. Most of the specialized coding for 80x86 is handled
190 * by just saying "FAR *" where such a pointer is needed. In a few places
191 * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
194 #ifdef NEED_FAR_POINTERS
204 * On a few systems, type boolean and/or its values FALSE, TRUE may appear
205 * in standard header files. Or you may have conflicts with application-
206 * specific header files that you want to include together with these files.
207 * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
210 //#ifndef HAVE_BOOLEAN
211 //typedef int boolean;
213 #ifndef FALSE /* in case these macros already exist */
214 #define FALSE 0 /* values of boolean */
222 * The remaining options affect code selection within the JPEG library,
223 * but they don't need to be visible to most applications using the library.
224 * To minimize application namespace pollution, the symbols won't be
225 * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
228 #ifdef JPEG_INTERNALS
229 #define JPEG_INTERNAL_OPTIONS
232 #ifdef JPEG_INTERNAL_OPTIONS
236 * These defines indicate whether to include various optional functions.
237 * Undefining some of these symbols will produce a smaller but less capable
238 * library. Note that you can leave certain source files out of the
239 * compilation/linking process if you've #undef'd the corresponding symbols.
240 * (You may HAVE to do that if your compiler doesn't like null source files.)
243 /* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */
245 /* Capability options common to encoder and decoder: */
247 #undef DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
248 #undef DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
249 #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
251 /* Encoder capability options: */
253 #undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
254 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
255 #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
256 #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
257 /* Note: if you selected 12-bit data precision, it is dangerous to turn off
258 * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit
259 * precision, so jchuff.c normally uses entropy optimization to compute
260 * usable tables for higher precision. If you don't want to do optimization,
261 * you'll have to supply different default Huffman tables.
262 * The exact same statements apply for progressive JPEG: the default tables
263 * don't work for progressive mode. (This may get fixed, however.)
265 #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
267 /* Decoder capability options: */
269 #undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
270 #undef D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
271 #undef D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
272 #undef BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
273 #undef IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */
274 #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
275 #undef UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
276 #undef QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
277 #undef QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
279 /* more capability options later, no doubt */
283 * Ordering of RGB data in scanlines passed to or from the application.
284 * If your application wants to deal with data in the order B,G,R, just
285 * change these macros. You can also deal with formats such as R,G,B,X
286 * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
287 * the offsets will also change the order in which colormap data is organized.
289 * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
290 * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
291 * useful if you are using JPEG color spaces other than YCbCr or grayscale.
292 * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
293 * is not 3 (they don't understand about dummy color components!). So you
294 * can't use color quantization if you change that value.
297 #define RGB_RED 0 /* Offset of Red in an RGB scanline element */
298 #define RGB_GREEN 1 /* Offset of Green */
299 #define RGB_BLUE 2 /* Offset of Blue */
300 // http://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=900
301 // ydnar: setting this fucks jpeg loading in q3map2, disabling "fix" (3)
302 #define RGB_PIXELSIZE 4 /* JSAMPLEs per RGB scanline element */
305 /* Definitions for speed-related optimizations. */
308 /* If your compiler supports inline functions, define INLINE
309 * as the inline keyword; otherwise define it as empty.
313 #ifdef __GNUC__ /* for instance, GNU C knows about inline */
314 #define INLINE __inline__
317 #define INLINE /* default is to define it as empty */
322 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
323 * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
324 * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
328 #define MULTIPLIER int /* type for fastest integer multiply */
332 /* FAST_FLOAT should be either float or double, whichever is done faster
333 * by your compiler. (Note that this type is only used in the floating point
334 * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
335 * Typically, float is faster in ANSI C compilers, while double is faster in
336 * pre-ANSI compilers (because they insist on converting to double anyway).
337 * The code below therefore chooses float if we have ANSI-style prototypes.
341 #ifdef HAVE_PROTOTYPES
342 #define FAST_FLOAT float
344 #define FAST_FLOAT double
348 #endif /* JPEG_INTERNAL_OPTIONS */