1 /* 2 * jmorecfg.h 3 * 4 * Copyright (C) 1991-1997, 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. 7 * 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. 11 */ 12 13 14 /* 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. 21 */ 22 23 /* use 8 or 12 */ 24 #define BITS_IN_JSAMPLE 8 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 #if !defined(XMD_H) && !defined(_WIN32) /* 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 /* 228 * Added note [10 Jul 08]: 229 * The jpeg library may crash if it is compiled with a different jmorecfg.h. 230 * For example, if compiled under MSVC with 231 * typedef unsigned char boolean; 232 * there will be a runtime error due to a struct size mismatch 233 * if you use this file with 234 * typedef int boolean; 235 */ 236 237 #ifndef HAVE_BOOLEAN 238 typedef int boolean; 239 #endif 240 #ifndef FALSE /* in case these macros already exist */ 241 #define FALSE 0 /* values of boolean */ 242 #endif 243 #ifndef TRUE 244 #define TRUE 1 245 #endif 246 247 248 /* 249 * The remaining options affect code selection within the JPEG library, 250 * but they don't need to be visible to most applications using the library. 251 * To minimize application namespace pollution, the symbols won't be 252 * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined. 253 */ 254 255 #ifdef JPEG_INTERNALS 256 #define JPEG_INTERNAL_OPTIONS 257 #endif 258 259 #ifdef JPEG_INTERNAL_OPTIONS 260 261 262 /* 263 * These defines indicate whether to include various optional functions. 264 * Undefining some of these symbols will produce a smaller but less capable 265 * library. Note that you can leave certain source files out of the 266 * compilation/linking process if you've #undef'd the corresponding symbols. 267 * (You may HAVE to do that if your compiler doesn't like null source files.) 268 */ 269 270 /* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */ 271 272 /* Capability options common to encoder and decoder: */ 273 274 #define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */ 275 #define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */ 276 #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */ 277 278 /* Encoder capability options: */ 279 280 #undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */ 281 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */ 282 #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/ 283 #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */ 284 /* Note: if you selected 12-bit data precision, it is dangerous to turn off 285 * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit 286 * precision, so jchuff.c normally uses entropy optimization to compute 287 * usable tables for higher precision. If you don't want to do optimization, 288 * you'll have to supply different default Huffman tables. 289 * The exact same statements apply for progressive JPEG: the default tables 290 * don't work for progressive mode. (This may get fixed, however.) 291 */ 292 #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */ 293 294 /* Decoder capability options: */ 295 296 #undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */ 297 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */ 298 #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/ 299 #define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */ 300 #define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */ 301 #define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */ 302 #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */ 303 #define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */ 304 #define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */ 305 #define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */ 306 307 /* more capability options later, no doubt */ 308 309 310 /* 311 * Ordering of RGB data in scanlines passed to or from the application. 312 * If your application wants to deal with data in the order B,G,R, just 313 * change these macros. You can also deal with formats such as R,G,B,X 314 * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing 315 * the offsets will also change the order in which colormap data is organized. 316 * RESTRICTIONS: 317 * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats. 318 * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not 319 * useful if you are using JPEG color spaces other than YCbCr or grayscale. 320 * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE 321 * is not 3 (they don't understand about dummy color components!). So you 322 * can't use color quantization if you change that value. 323 */ 324 325 #define RGB_RED 0 /* Offset of Red in an RGB scanline element */ 326 #define RGB_GREEN 1 /* Offset of Green */ 327 #define RGB_BLUE 2 /* Offset of Blue */ 328 #define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */ 329 330 331 /* Definitions for speed-related optimizations. */ 332 333 334 /* If your compiler supports inline functions, define INLINE 335 * as the inline keyword; otherwise define it as empty. 336 */ 337 338 #ifndef INLINE 339 #ifdef __GNUC__ /* for instance, GNU C knows about inline */ 340 #define INLINE __inline__ 341 #endif 342 #ifndef INLINE 343 #define INLINE /* default is to define it as empty */ 344 #endif 345 #endif 346 347 348 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying 349 * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER 350 * as short on such a machine. MULTIPLIER must be at least 16 bits wide. 351 */ 352 353 #ifndef MULTIPLIER 354 #define MULTIPLIER int /* type for fastest integer multiply */ 355 #endif 356 357 358 /* FAST_FLOAT should be either float or double, whichever is done faster 359 * by your compiler. (Note that this type is only used in the floating point 360 * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.) 361 * Typically, float is faster in ANSI C compilers, while double is faster in 362 * pre-ANSI compilers (because they insist on converting to double anyway). 363 * The code below therefore chooses float if we have ANSI-style prototypes. 364 */ 365 366 #ifndef FAST_FLOAT 367 #ifdef HAVE_PROTOTYPES 368 #define FAST_FLOAT float 369 #else 370 #define FAST_FLOAT double 371 #endif 372 #endif 373 374 #endif /* JPEG_INTERNAL_OPTIONS */ 375