00001 /* 00002 * jmorecfg.h 00003 * 00004 * Copyright (C) 1991-1998, Thomas G. Lane. 00005 * This file is part of the Independent JPEG Group's software. 00006 * For conditions of distribution and use, see the accompanying README file. 00007 * 00008 * This file contains additional configuration options that customize the 00009 * JPEG software for special applications or support machine-dependent 00010 * optimizations. Most users will not need to touch this file. 00011 */ 00012 00013 00014 /* 00015 * Define BITS_IN_JSAMPLE as either 00016 * 8 for 8-bit sample values (the usual setting) 00017 * 12 for 12-bit sample values 00018 * Only 8 and 12 are legal data precisions for lossy JPEG according to the 00019 * JPEG standard, and the IJG code does not support anything else! 00020 * We do not support run-time selection of data precision, sorry. 00021 */ 00022 00023 #define BITS_IN_JSAMPLE 8 /* use 8 or 12 (or 16 for lossless) */ 00024 00025 00026 /* 00027 * Maximum number of components (color channels) allowed in JPEG image. 00028 * To meet the letter of the JPEG spec, set this to 255. However, darn 00029 * few applications need more than 4 channels (maybe 5 for CMYK + alpha 00030 * mask). We recommend 10 as a reasonable compromise; use 4 if you are 00031 * really short on memory. (Each allowed component costs a hundred or so 00032 * bytes of storage, whether actually used in an image or not.) 00033 */ 00034 00035 #define MAX_COMPONENTS 10 /* maximum number of image components */ 00036 00037 00038 /* 00039 * Basic data types. 00040 * You may need to change these if you have a machine with unusual data 00041 * type sizes; for example, "char" not 8 bits, "short" not 16 bits, 00042 * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits, 00043 * but it had better be at least 16. 00044 */ 00045 00046 /* Representation of a single sample (pixel element value). 00047 * We frequently allocate large arrays of these, so it's important to keep 00048 * them small. But if you have memory to burn and access to char or short 00049 * arrays is very slow on your hardware, you might want to change these. 00050 */ 00051 00052 #if BITS_IN_JSAMPLE == 8 00053 /* JSAMPLE should be the smallest type that will hold the values 0..255. 00054 * You can use a signed char by having GETJSAMPLE mask it with 0xFF. 00055 */ 00056 00057 #ifdef HAVE_UNSIGNED_CHAR 00058 00059 typedef unsigned char JSAMPLE; 00060 #define GETJSAMPLE(value) ((int) (value)) 00061 00062 #else /* not HAVE_UNSIGNED_CHAR */ 00063 00064 typedef char JSAMPLE; 00065 #ifdef CHAR_IS_UNSIGNED 00066 #define GETJSAMPLE(value) ((int) (value)) 00067 #else 00068 #define GETJSAMPLE(value) ((int) (value) & 0xFF) 00069 #endif /* CHAR_IS_UNSIGNED */ 00070 00071 #endif /* HAVE_UNSIGNED_CHAR */ 00072 00073 #define MAXJSAMPLE 255 00074 #define CENTERJSAMPLE 128 00075 00076 #endif /* BITS_IN_JSAMPLE == 8 */ 00077 00078 00079 #if BITS_IN_JSAMPLE == 12 00080 /* JSAMPLE should be the smallest type that will hold the values 0..4095. 00081 * On nearly all machines "short" will do nicely. 00082 */ 00083 00084 typedef short JSAMPLE; 00085 #define GETJSAMPLE(value) ((int) (value)) 00086 00087 #define MAXJSAMPLE 4095 00088 #define CENTERJSAMPLE 2048 00089 00090 #endif /* BITS_IN_JSAMPLE == 12 */ 00091 00092 00093 #if BITS_IN_JSAMPLE == 16 00094 /* JSAMPLE should be the smallest type that will hold the values 0..65535. 00095 * You can use a signed short by having GETJSAMPLE mask it with 0xFFFF. 00096 */ 00097 00098 #ifdef HAVE_UNSIGNED_SHORT 00099 00100 typedef unsigned short JSAMPLE; 00101 #define GETJSAMPLE(value) ((int) (value)) 00102 00103 #else /* not HAVE_UNSIGNED_SHORT */ 00104 00105 typedef short JSAMPLE; 00106 #ifdef SHORT_IS_UNSIGNED 00107 #define GETJSAMPLE(value) ((int) (value)) 00108 #else 00109 #define GETJSAMPLE(value) ((int) (value) & 0xFFFF) 00110 #endif /* SHORT_IS_UNSIGNED */ 00111 00112 #endif /* HAVE_UNSIGNED_SHORT */ 00113 00114 #define MAXJSAMPLE 65535 00115 #define CENTERJSAMPLE 32768 00116 00117 #endif /* BITS_IN_JSAMPLE == 16 */ 00118 00119 00120 /* Representation of a DCT frequency coefficient. 00121 * This should be a signed value of at least 16 bits; "short" is usually OK. 00122 * Again, we allocate large arrays of these, but you can change to int 00123 * if you have memory to burn and "short" is really slow. 00124 */ 00125 00126 typedef short JCOEF; 00127 00128 00129 /* Representation of a spatial difference value. 00130 * This should be a signed value of at least 16 bits; int is usually OK. 00131 */ 00132 00133 typedef int JDIFF; 00134 00135 00136 /* Compressed datastreams are represented as arrays of JOCTET. 00137 * These must be EXACTLY 8 bits wide, at least once they are written to 00138 * external storage. Note that when using the stdio data source/destination 00139 * managers, this is also the data type passed to fread/fwrite. 00140 */ 00141 00142 #ifdef HAVE_UNSIGNED_CHAR 00143 00144 typedef unsigned char JOCTET; 00145 #define GETJOCTET(value) (value) 00146 00147 #else /* not HAVE_UNSIGNED_CHAR */ 00148 00149 typedef char JOCTET; 00150 #ifdef CHAR_IS_UNSIGNED 00151 #define GETJOCTET(value) (value) 00152 #else 00153 #define GETJOCTET(value) ((value) & 0xFF) 00154 #endif /* CHAR_IS_UNSIGNED */ 00155 00156 #endif /* HAVE_UNSIGNED_CHAR */ 00157 00158 00159 /* These typedefs are used for various table entries and so forth. 00160 * They must be at least as wide as specified; but making them too big 00161 * won't cost a huge amount of memory, so we don't provide special 00162 * extraction code like we did for JSAMPLE. (In other words, these 00163 * typedefs live at a different point on the speed/space tradeoff curve.) 00164 */ 00165 00166 /* UINT8 must hold at least the values 0..255. */ 00167 00168 #ifdef HAVE_UNSIGNED_CHAR 00169 typedef unsigned char UINT8; 00170 #else /* not HAVE_UNSIGNED_CHAR */ 00171 #ifdef CHAR_IS_UNSIGNED 00172 typedef char UINT8; 00173 #else /* not CHAR_IS_UNSIGNED */ 00174 typedef short UINT8; 00175 #endif /* CHAR_IS_UNSIGNED */ 00176 #endif /* HAVE_UNSIGNED_CHAR */ 00177 00178 /* UINT16 must hold at least the values 0..65535. */ 00179 00180 #ifdef HAVE_UNSIGNED_SHORT 00181 typedef unsigned short UINT16; 00182 #else /* not HAVE_UNSIGNED_SHORT */ 00183 typedef unsigned int UINT16; 00184 #endif /* HAVE_UNSIGNED_SHORT */ 00185 00186 /* INT16 must hold at least the values -32768..32767. */ 00187 00188 #ifndef XMD_H /* X11/xmd.h correctly defines INT16 */ 00189 typedef short INT16; 00190 #endif 00191 00192 /* IJG_INT32 must hold at least signed 32-bit values. */ 00193 typedef long IJG_INT32; 00194 00195 /* Datatype used for image dimensions. The JPEG standard only supports 00196 * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore 00197 * "unsigned int" is sufficient on all machines. However, if you need to 00198 * handle larger images and you don't mind deviating from the spec, you 00199 * can change this datatype. 00200 */ 00201 00202 typedef unsigned int JDIMENSION; 00203 00204 #define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */ 00205 00206 00207 /* These macros are used in all function definitions and extern declarations. 00208 * You could modify them if you need to change function linkage conventions; 00209 * in particular, you'll need to do that to make the library a Windows DLL. 00210 * Another application is to make all functions global for use with debuggers 00211 * or code profilers that require it. 00212 */ 00213 00214 /* a function called through method pointers: */ 00215 #define METHODDEF(type) static type 00216 /* a function used only in its module: */ 00217 #define LOCAL(type) static type 00218 /* a function referenced thru EXTERNs: */ 00219 #define GLOBAL(type) type 00220 /* a reference to a GLOBAL function: */ 00221 #define EXTERN(type) extern type 00222 00223 00224 /* This macro is used to declare a "method", that is, a function pointer. 00225 * We want to supply prototype parameters if the compiler can cope. 00226 * Note that the arglist parameter must be parenthesized! 00227 * Again, you can customize this if you need special linkage keywords. 00228 */ 00229 00230 #ifdef HAVE_PROTOTYPES 00231 #define JMETHOD(type,methodname,arglist) type (*methodname) arglist 00232 #else 00233 #define JMETHOD(type,methodname,arglist) type (*methodname) () 00234 #endif 00235 00236 00237 /* Here is the pseudo-keyword for declaring pointers that must be "far" 00238 * on 80x86 machines. Most of the specialized coding for 80x86 is handled 00239 * by just saying "FAR *" where such a pointer is needed. In a few places 00240 * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol. 00241 */ 00242 00243 #undef FAR 00244 #ifdef NEED_FAR_POINTERS 00245 #define FAR far 00246 #else 00247 #define FAR 00248 #endif 00249 00250 00251 /* 00252 * On a few systems, type boolean and/or its values FALSE, TRUE may appear 00253 * in standard header files. Or you may have conflicts with application- 00254 * specific header files that you want to include together with these files. 00255 * Defining HAVE_BOOLEAN before including jpeglib.h should make it work. 00256 */ 00257 00258 #ifndef HAVE_BOOLEAN 00259 typedef int boolean; 00260 #endif 00261 #ifndef FALSE /* in case these macros already exist */ 00262 #define FALSE 0 /* values of boolean */ 00263 #endif 00264 #ifndef TRUE 00265 #define TRUE 1 00266 #endif 00267 00268 00269 /* 00270 * The remaining options affect code selection within the JPEG library, 00271 * but they don't need to be visible to most applications using the library. 00272 * To minimize application namespace pollution, the symbols won't be 00273 * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined. 00274 */ 00275 00276 #ifdef JPEG_INTERNALS 00277 #define JPEG_INTERNAL_OPTIONS 00278 #endif 00279 00280 #ifdef JPEG_INTERNAL_OPTIONS 00281 00282 00283 /* 00284 * These defines indicate whether to include various optional functions. 00285 * Undefining some of these symbols will produce a smaller but less capable 00286 * library. Note that you can leave certain source files out of the 00287 * compilation/linking process if you've #undef'd the corresponding symbols. 00288 * (You may HAVE to do that if your compiler doesn't like null source files.) 00289 */ 00290 00291 /* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */ 00292 00293 /* Capability options common to encoder and decoder: */ 00294 00295 #define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */ 00296 #define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */ 00297 #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */ 00298 00299 /* Encoder capability options: */ 00300 00301 #undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */ 00302 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */ 00303 #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/ 00304 #define C_LOSSLESS_SUPPORTED /* Lossless JPEG? */ 00305 #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */ 00306 /* Note: if you selected 12-bit data precision, it is dangerous to turn off 00307 * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit 00308 * precision, so jcshuff.c normally uses entropy optimization to compute 00309 * usable tables for higher precision. If you don't want to do optimization, 00310 * you'll have to supply different default Huffman tables. 00311 * The exact same statements apply for progressive and lossless JPEG: 00312 * the default tables don't work for progressive mode or lossless mode. 00313 * (This may get fixed, however.) 00314 */ 00315 #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */ 00316 00317 /* Decoder capability options: */ 00318 00319 #undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */ 00320 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */ 00321 #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/ 00322 #define D_LOSSLESS_SUPPORTED /* Lossless JPEG? */ 00323 #define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */ 00324 #define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */ 00325 #define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */ 00326 #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */ 00327 #define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */ 00328 #define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */ 00329 #define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */ 00330 00331 /* more capability options later, no doubt */ 00332 00333 00334 /* 00335 * Ordering of RGB data in scanlines passed to or from the application. 00336 * If your application wants to deal with data in the order B,G,R, just 00337 * change these macros. You can also deal with formats such as R,G,B,X 00338 * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing 00339 * the offsets will also change the order in which colormap data is organized. 00340 * RESTRICTIONS: 00341 * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats. 00342 * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not 00343 * useful if you are using JPEG color spaces other than YCbCr or grayscale. 00344 * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE 00345 * is not 3 (they don't understand about dummy color components!). So you 00346 * can't use color quantization if you change that value. 00347 */ 00348 00349 #define RGB_RED 0 /* Offset of Red in an RGB scanline element */ 00350 #define RGB_GREEN 1 /* Offset of Green */ 00351 #define RGB_BLUE 2 /* Offset of Blue */ 00352 #define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */ 00353 00354 00355 /* Definitions for speed-related optimizations. */ 00356 00357 00358 /* If your compiler supports inline functions, define INLINE 00359 * as the inline keyword; otherwise define it as empty. 00360 */ 00361 00362 #ifndef INLINE 00363 #ifdef __GNUC__ /* for instance, GNU C knows about inline */ 00364 #define INLINE __inline__ 00365 #endif 00366 #ifndef INLINE 00367 #define INLINE /* default is to define it as empty */ 00368 #endif 00369 #endif 00370 00371 00372 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying 00373 * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER 00374 * as short on such a machine. MULTIPLIER must be at least 16 bits wide. 00375 */ 00376 00377 #ifndef MULTIPLIER 00378 #define MULTIPLIER int /* type for fastest integer multiply */ 00379 #endif 00380 00381 00382 /* FAST_FLOAT should be either float or double, whichever is done faster 00383 * by your compiler. (Note that this type is only used in the floating point 00384 * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.) 00385 * Typically, float is faster in ANSI C compilers, while double is faster in 00386 * pre-ANSI compilers (because they insist on converting to double anyway). 00387 * The code below therefore chooses float if we have ANSI-style prototypes. 00388 */ 00389 00390 #ifndef FAST_FLOAT 00391 #ifdef HAVE_PROTOTYPES 00392 #define FAST_FLOAT float 00393 #else 00394 #define FAST_FLOAT double 00395 #endif 00396 #endif 00397 00398 #endif /* JPEG_INTERNAL_OPTIONS */