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| 1 /* |
| 2 * jmorecfg.h |
| 3 * |
| 4 * Copyright (C) 1991-1997, Thomas G. Lane. |
| 5 * Copyright (C) 2009, D. R. Commander. |
| 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_UNSIGNED__ |
| 67 #define GETJSAMPLE(value) ((int) (value)) |
| 68 #else |
| 69 #define GETJSAMPLE(value) ((int) (value) & 0xFF) |
| 70 #endif /* __CHAR_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_UNSIGNED__ |
| 118 #define GETJOCTET(value) (value) |
| 119 #else |
| 120 #define GETJOCTET(value) ((value) & 0xFF) |
| 121 #endif /* __CHAR_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_UNSIGNED__ |
| 139 typedef char UINT8; |
| 140 #else /* not __CHAR_UNSIGNED__ */ |
| 141 typedef short UINT8; |
| 142 #endif /* __CHAR_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 typedef long INT32; |
| 163 #endif |
| 164 |
| 165 /* Datatype used for image dimensions. The JPEG standard only supports |
| 166 * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore |
| 167 * "unsigned int" is sufficient on all machines. However, if you need to |
| 168 * handle larger images and you don't mind deviating from the spec, you |
| 169 * can change this datatype. |
| 170 */ |
| 171 |
| 172 typedef unsigned int JDIMENSION; |
| 173 |
| 174 #define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */ |
| 175 |
| 176 |
| 177 /* These macros are used in all function definitions and extern declarations. |
| 178 * You could modify them if you need to change function linkage conventions; |
| 179 * in particular, you'll need to do that to make the library a Windows DLL. |
| 180 * Another application is to make all functions global for use with debuggers |
| 181 * or code profilers that require it. |
| 182 */ |
| 183 |
| 184 /* a function called through method pointers: */ |
| 185 #define METHODDEF(type) static type |
| 186 /* a function used only in its module: */ |
| 187 #define LOCAL(type) static type |
| 188 /* a function referenced thru EXTERNs: */ |
| 189 #define GLOBAL(type) type |
| 190 /* a reference to a GLOBAL function: */ |
| 191 #define EXTERN(type) extern type |
| 192 |
| 193 |
| 194 /* This macro is used to declare a "method", that is, a function pointer. |
| 195 * We want to supply prototype parameters if the compiler can cope. |
| 196 * Note that the arglist parameter must be parenthesized! |
| 197 * Again, you can customize this if you need special linkage keywords. |
| 198 */ |
| 199 |
| 200 #ifdef HAVE_PROTOTYPES |
| 201 #define JMETHOD(type,methodname,arglist) type (*methodname) arglist |
| 202 #else |
| 203 #define JMETHOD(type,methodname,arglist) type (*methodname) () |
| 204 #endif |
| 205 |
| 206 |
| 207 /* Here is the pseudo-keyword for declaring pointers that must be "far" |
| 208 * on 80x86 machines. Most of the specialized coding for 80x86 is handled |
| 209 * by just saying "FAR *" where such a pointer is needed. In a few places |
| 210 * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol. |
| 211 */ |
| 212 |
| 213 #ifdef NEED_FAR_POINTERS |
| 214 #define FAR far |
| 215 #else |
| 216 #define FAR |
| 217 #endif |
| 218 |
| 219 |
| 220 /* |
| 221 * On a few systems, type boolean and/or its values FALSE, TRUE may appear |
| 222 * in standard header files. Or you may have conflicts with application- |
| 223 * specific header files that you want to include together with these files. |
| 224 * Defining HAVE_BOOLEAN before including jpeglib.h should make it work. |
| 225 */ |
| 226 |
| 227 #ifndef HAVE_BOOLEAN |
| 228 typedef int boolean; |
| 229 #endif |
| 230 #ifndef FALSE /* in case these macros already exist */ |
| 231 #define FALSE 0 /* values of boolean */ |
| 232 #endif |
| 233 #ifndef TRUE |
| 234 #define TRUE 1 |
| 235 #endif |
| 236 |
| 237 |
| 238 /* |
| 239 * The remaining options affect code selection within the JPEG library, |
| 240 * but they don't need to be visible to most applications using the library. |
| 241 * To minimize application namespace pollution, the symbols won't be |
| 242 * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined. |
| 243 */ |
| 244 |
| 245 #ifdef JPEG_INTERNALS |
| 246 #define JPEG_INTERNAL_OPTIONS |
| 247 #endif |
| 248 |
| 249 #ifdef JPEG_INTERNAL_OPTIONS |
| 250 |
| 251 |
| 252 /* |
| 253 * These defines indicate whether to include various optional functions. |
| 254 * Undefining some of these symbols will produce a smaller but less capable |
| 255 * library. Note that you can leave certain source files out of the |
| 256 * compilation/linking process if you've #undef'd the corresponding symbols. |
| 257 * (You may HAVE to do that if your compiler doesn't like null source files.) |
| 258 */ |
| 259 |
| 260 /* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */ |
| 261 |
| 262 /* Capability options common to encoder and decoder: */ |
| 263 |
| 264 #define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */ |
| 265 #define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */ |
| 266 #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */ |
| 267 |
| 268 /* Encoder capability options: */ |
| 269 |
| 270 #undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */ |
| 271 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */ |
| 272 #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/ |
| 273 #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */ |
| 274 /* Note: if you selected 12-bit data precision, it is dangerous to turn off |
| 275 * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit |
| 276 * precision, so jchuff.c normally uses entropy optimization to compute |
| 277 * usable tables for higher precision. If you don't want to do optimization, |
| 278 * you'll have to supply different default Huffman tables. |
| 279 * The exact same statements apply for progressive JPEG: the default tables |
| 280 * don't work for progressive mode. (This may get fixed, however.) |
| 281 */ |
| 282 #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */ |
| 283 |
| 284 /* Decoder capability options: */ |
| 285 |
| 286 #undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */ |
| 287 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */ |
| 288 #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/ |
| 289 #define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */ |
| 290 #define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */ |
| 291 #define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */ |
| 292 #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */ |
| 293 #define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */ |
| 294 #define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */ |
| 295 #define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */ |
| 296 |
| 297 /* more capability options later, no doubt */ |
| 298 |
| 299 |
| 300 /* |
| 301 * Ordering of RGB data in scanlines passed to or from the application. |
| 302 * If your application wants to deal with data in the order B,G,R, just |
| 303 * change these macros. You can also deal with formats such as R,G,B,X |
| 304 * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing |
| 305 * the offsets will also change the order in which colormap data is organized. |
| 306 * RESTRICTIONS: |
| 307 * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats. |
| 308 * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not |
| 309 * useful if you are using JPEG color spaces other than YCbCr or grayscale. |
| 310 * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE |
| 311 * is not 3 (they don't understand about dummy color components!). So you |
| 312 * can't use color quantization if you change that value. |
| 313 */ |
| 314 |
| 315 #define RGB_RED 0 /* Offset of Red in an RGB scanline element */ |
| 316 #define RGB_GREEN 1 /* Offset of Green */ |
| 317 #define RGB_BLUE 2 /* Offset of Blue */ |
| 318 #define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */ |
| 319 |
| 320 #define JPEG_NUMCS 12 |
| 321 |
| 322 static const int rgb_red[JPEG_NUMCS] = { |
| 323 -1, -1, RGB_RED, -1, -1, -1, 0, 0, 2, 2, 3, 1 |
| 324 }; |
| 325 |
| 326 static const int rgb_green[JPEG_NUMCS] = { |
| 327 -1, -1, RGB_GREEN, -1, -1, -1, 1, 1, 1, 1, 2, 2 |
| 328 }; |
| 329 |
| 330 static const int rgb_blue[JPEG_NUMCS] = { |
| 331 -1, -1, RGB_BLUE, -1, -1, -1, 2, 2, 0, 0, 1, 3 |
| 332 }; |
| 333 |
| 334 static const int rgb_pixelsize[JPEG_NUMCS] = { |
| 335 -1, -1, RGB_PIXELSIZE, -1, -1, -1, 3, 4, 3, 4, 4, 4 |
| 336 }; |
| 337 |
| 338 /* Definitions for speed-related optimizations. */ |
| 339 |
| 340 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying |
| 341 * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER |
| 342 * as short on such a machine. MULTIPLIER must be at least 16 bits wide. |
| 343 */ |
| 344 |
| 345 #ifndef MULTIPLIER |
| 346 #ifndef WITH_SIMD |
| 347 #define MULTIPLIER int /* type for fastest integer multiply */ |
| 348 #else |
| 349 #define MULTIPLIER short /* prefer 16-bit with SIMD for parellelism */ |
| 350 #endif |
| 351 #endif |
| 352 |
| 353 |
| 354 /* FAST_FLOAT should be either float or double, whichever is done faster |
| 355 * by your compiler. (Note that this type is only used in the floating point |
| 356 * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.) |
| 357 * Typically, float is faster in ANSI C compilers, while double is faster in |
| 358 * pre-ANSI compilers (because they insist on converting to double anyway). |
| 359 * The code below therefore chooses float if we have ANSI-style prototypes. |
| 360 */ |
| 361 |
| 362 #ifndef FAST_FLOAT |
| 363 #ifdef HAVE_PROTOTYPES |
| 364 #define FAST_FLOAT float |
| 365 #else |
| 366 #define FAST_FLOAT double |
| 367 #endif |
| 368 #endif |
| 369 |
| 370 #endif /* JPEG_INTERNAL_OPTIONS */ |
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