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