src/jpeg/jmorecfg.h

   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 #define BITS_IN_JSAMPLE  8      /* use 8 or 12 */
  24
  25
  26 /*
  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.)
  33  */
  34
  35 #define MAX_COMPONENTS  10      /* maximum number of image components */
  36
  37
  38 /*
  39  * Basic data types.
  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.
  44  */
  45
  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.
  50  */
  51
  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.
  55  */
  56
  57 #ifdef HAVE_UNSIGNED_CHAR
  58
  59 typedef unsigned char JSAMPLE;
  60 #define GETJSAMPLE(value)  ((int) (value))
  61
  62 #else /* not HAVE_UNSIGNED_CHAR */
  63
  64 typedef char JSAMPLE;
  65 #ifdef CHAR_IS_UNSIGNED
  66 #define GETJSAMPLE(value)  ((int) (value))
  67 #else
  68 #define GETJSAMPLE(value)  ((int) (value) & 0xFF)
  69 #endif /* CHAR_IS_UNSIGNED */
  70
  71 #endif /* HAVE_UNSIGNED_CHAR */
  72
  73 #define MAXJSAMPLE      255
  74 #define CENTERJSAMPLE   128
  75
  76 #endif /* BITS_IN_JSAMPLE == 8 */
  77
  78
  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.
  82  */
  83
  84 typedef short JSAMPLE;
  85 #define GETJSAMPLE(value)  ((int) (value))
  86
  87 #define MAXJSAMPLE      4095
  88 #define CENTERJSAMPLE   2048
  89
  90 #endif /* BITS_IN_JSAMPLE == 12 */
  91
  92
  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.
  97  */
  98
  99 typedef short JCOEF;
 100
 101
 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.
 106  */
 107
 108 #ifdef HAVE_UNSIGNED_CHAR
 109
 110 typedef unsigned char JOCTET;
 111 #define GETJOCTET(value)  (value)
 112
 113 #else /* not HAVE_UNSIGNED_CHAR */
 114
 115 typedef char JOCTET;
 116 #ifdef CHAR_IS_UNSIGNED
 117 #define GETJOCTET(value)  (value)
 118 #else
 119 #define GETJOCTET(value)  ((value) & 0xFF)
 120 #endif /* CHAR_IS_UNSIGNED */
 121
 122 #endif /* HAVE_UNSIGNED_CHAR */
 123
 124
 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.)
 130  */
 131
 132 /* UINT8 must hold at least the values 0..255. */
 133
 134 #ifdef HAVE_UNSIGNED_CHAR
 135 typedef unsigned char UINT8;
 136 #else /* not HAVE_UNSIGNED_CHAR */
 137 #ifdef CHAR_IS_UNSIGNED
 138 typedef char UINT8;
 139 #else /* not CHAR_IS_UNSIGNED */
 140 typedef short UINT8;
 141 #endif /* CHAR_IS_UNSIGNED */
 142 #endif /* HAVE_UNSIGNED_CHAR */
 143
 144 /* UINT16 must hold at least the values 0..65535. */
 145
 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 */
 151
 152 /* INT16 must hold at least the values -32768..32767. */
 153
 154 #ifndef XMD_H                   /* X11/xmd.h correctly defines INT16 */
 155 typedef short INT16;
 156 #endif
 157
 158 /* INT32 must hold at least signed 32-bit values. */
 159
 160 /*
 161     VZ: due to the horrible mess resulting in INT32 being defined in windows.h
 162         for some compilers but not for the other ones, I have globally replace
 163         INT32 with JPEG_INT32 in libjpeg code to avoid the eight level ifdef
 164         which used to be here. The problem is that, of course, now we'll have
 165         conflicts when upgrading to the next libjpeg release -- however
 166         considering their frequency (1 in the last 5 years) it seems that
 167         it is not too high a price to pay for the clean compilation with all
 168         versions of mingw32 and cygwin
 169  */
 170 typedef long JPEG_INT32;
 171
 172 /* Datatype used for image dimensions.  The JPEG standard only supports
 173  * images up to 64K*64K due to 16-bit fields in SOF markers.  Therefore
 174  * "unsigned int" is sufficient on all machines.  However, if you need to
 175  * handle larger images and you don't mind deviating from the spec, you
 176  * can change this datatype.
 177  */
 178
 179 typedef unsigned int JDIMENSION;
 180
 181 #define JPEG_MAX_DIMENSION  65500L  /* a tad under 64K to prevent overflows */
 182
 183
 184 /* These macros are used in all function definitions and extern declarations.
 185  * You could modify them if you need to change function linkage conventions;
 186  * in particular, you'll need to do that to make the library a Windows DLL.
 187  * Another application is to make all functions global for use with debuggers
 188  * or code profilers that require it.
 189  */
 190
 191 #if defined(__VISAGECPP__)
 192 #define JPEG_CALLING_CONV _Optlink
 193 #else /* !Visual Age C++ */
 194 #define JPEG_CALLING_CONV
 195 #endif
 196
 197 /* We can't declare a static function as extern "C" as we need to do in C++
 198  * programs, so suppress static in METHODDEF when using C++.
 199  */
 200 #if defined(__cplusplus)
 201 #define JPEG_METHOD_LINKAGE
 202 #else /* !__cplusplus */
 203 #define JPEG_METHOD_LINKAGE static
 204 #endif
 205
 206 /* a function called through method pointers: */
 207 #define METHODDEF(type)         JPEG_METHOD_LINKAGE type JPEG_CALLING_CONV
 208 /* a function used only in its module: */
 209 #define LOCAL(type)             static type JPEG_CALLING_CONV
 210 /* a function referenced thru EXTERNs: */
 211 #define GLOBAL(type)            type
 212 /* a reference to a GLOBAL function: */
 213 #define EXTERN(type)            extern type JPEG_CALLING_CONV
 214
 215 /* This macro is used to declare a "method", that is, a function pointer.
 216  * We want to supply prototype parameters if the compiler can cope.
 217  * Note that the arglist parameter must be parenthesized!
 218  * Again, you can customize this if you need special linkage keywords.
 219  */
 220
 221 #if defined(__VISAGECPP__) /* need this for /common/imagjpeg.obj but not loclly */
 222 #ifdef HAVE_PROTOTYPES
 223 #define JMETHOD(type,methodname,arglist)  type (_Optlink *methodname) arglist
 224 #else
 225 #define JMETHOD(type,methodname,arglist)  type (_Optlink *methodname) ()
 226 #endif
 227
 228 #else
 229
 230 #ifdef HAVE_PROTOTYPES
 231 #define JMETHOD(type,methodname,arglist)  type (*methodname) arglist
 232 #else
 233 #define JMETHOD(type,methodname,arglist)  type (*methodname) ()
 234 #endif
 235
 236 #endif
 237
 238 /* Here is the pseudo-keyword for declaring pointers that must be "far"
 239  * on 80x86 machines.  Most of the specialized coding for 80x86 is handled
 240  * by just saying "FAR *" where such a pointer is needed.  In a few places
 241  * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
 242  */
 243
 244 #ifdef NEED_FAR_POINTERS
 245 #define FAR  far
 246 #else
 247 #ifndef FAR
 248 #define FAR
 249 #endif
 250 #endif
 251
 252
 253 /*
 254  * On a few systems, type boolean and/or its values FALSE, TRUE may appear
 255  * in standard header files.  Or you may have conflicts with application-
 256  * specific header files that you want to include together with these files.
 257  * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
 258  */
 259
 260 #ifndef HAVE_BOOLEAN
 261 typedef int boolean;
 262 #endif
 263 #ifndef FALSE                   /* in case these macros already exist */
 264 #define FALSE   0               /* values of boolean */
 265 #endif
 266 #ifndef TRUE
 267 #define TRUE    1
 268 #endif
 269
 270
 271 /*
 272  * The remaining options affect code selection within the JPEG library,
 273  * but they don't need to be visible to most applications using the library.
 274  * To minimize application namespace pollution, the symbols won't be
 275  * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
 276  */
 277
 278 #ifdef JPEG_INTERNALS
 279 #define JPEG_INTERNAL_OPTIONS
 280 #endif
 281
 282 #ifdef JPEG_INTERNAL_OPTIONS
 283
 284
 285 /*
 286  * These defines indicate whether to include various optional functions.
 287  * Undefining some of these symbols will produce a smaller but less capable
 288  * library.  Note that you can leave certain source files out of the
 289  * compilation/linking process if you've #undef'd the corresponding symbols.
 290  * (You may HAVE to do that if your compiler doesn't like null source files.)
 291  */
 292
 293 /* Arithmetic coding is unsupported for legal reasons.  Complaints to IBM. */
 294
 295 /* Capability options common to encoder and decoder: */
 296
 297 #define DCT_ISLOW_SUPPORTED     /* slow but accurate integer algorithm */
 298 #define DCT_IFAST_SUPPORTED     /* faster, less accurate integer method */
 299 #define DCT_FLOAT_SUPPORTED     /* floating-point: accurate, fast on fast HW */
 300
 301 /* Encoder capability options: */
 302
 303 #undef  C_ARITH_CODING_SUPPORTED    /* Arithmetic coding back end? */
 304 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
 305 #define C_PROGRESSIVE_SUPPORTED     /* Progressive JPEG? (Requires MULTISCAN)*/
 306 #define ENTROPY_OPT_SUPPORTED       /* Optimization of entropy coding parms? */
 307 /* Note: if you selected 12-bit data precision, it is dangerous to turn off
 308  * ENTROPY_OPT_SUPPORTED.  The standard Huffman tables are only good for 8-bit
 309  * precision, so jchuff.c normally uses entropy optimization to compute
 310  * usable tables for higher precision.  If you don't want to do optimization,
 311  * you'll have to supply different default Huffman tables.
 312  * The exact same statements apply for progressive JPEG: the default tables
 313  * don't work for progressive mode.  (This may get fixed, however.)
 314  */
 315 #define INPUT_SMOOTHING_SUPPORTED   /* Input image smoothing option? */
 316
 317 /* Decoder capability options: */
 318
 319 #undef  D_ARITH_CODING_SUPPORTED    /* Arithmetic coding back end? */
 320 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
 321 #define D_PROGRESSIVE_SUPPORTED     /* Progressive JPEG? (Requires MULTISCAN)*/
 322 #define SAVE_MARKERS_SUPPORTED      /* jpeg_save_markers() needed? */
 323 #define BLOCK_SMOOTHING_SUPPORTED   /* Block smoothing? (Progressive only) */
 324 #define IDCT_SCALING_SUPPORTED      /* Output rescaling via IDCT? */
 325 #undef  UPSAMPLE_SCALING_SUPPORTED  /* Output rescaling at upsample stage? */
 326 #define UPSAMPLE_MERGING_SUPPORTED  /* Fast path for sloppy upsampling? */
 327 #define QUANT_1PASS_SUPPORTED       /* 1-pass color quantization? */
 328 #define QUANT_2PASS_SUPPORTED       /* 2-pass color quantization? */
 329
 330 /* more capability options later, no doubt */
 331
 332
 333 /*
 334  * Ordering of RGB data in scanlines passed to or from the application.
 335  * If your application wants to deal with data in the order B,G,R, just
 336  * change these macros.  You can also deal with formats such as R,G,B,X
 337  * (one extra byte per pixel) by changing RGB_PIXELSIZE.  Note that changing
 338  * the offsets will also change the order in which colormap data is organized.
 339  * RESTRICTIONS:
 340  * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
 341  * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
 342  *    useful if you are using JPEG color spaces other than YCbCr or grayscale.
 343  * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
 344  *    is not 3 (they don't understand about dummy color components!).  So you
 345  *    can't use color quantization if you change that value.
 346  */
 347
 348 #define RGB_RED         0       /* Offset of Red in an RGB scanline element */
 349 #define RGB_GREEN       1       /* Offset of Green */
 350 #define RGB_BLUE        2       /* Offset of Blue */
 351 #define RGB_PIXELSIZE   3       /* JSAMPLEs per RGB scanline element */
 352
 353
 354 /* Definitions for speed-related optimizations. */
 355
 356
 357 /* If your compiler supports inline functions, define INLINE
 358  * as the inline keyword; otherwise define it as empty.
 359  */
 360
 361 #ifndef INLINE
 362 #ifdef __GNUC__                 /* for instance, GNU C knows about inline */
 363 #define INLINE __inline__
 364 #endif
 365 #ifndef INLINE
 366 #define INLINE                  /* default is to define it as empty */
 367 #endif
 368 #endif
 369
 370
 371 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
 372  * two 16-bit shorts is faster than multiplying two ints.  Define MULTIPLIER
 373  * as short on such a machine.  MULTIPLIER must be at least 16 bits wide.
 374  */
 375
 376 #ifndef MULTIPLIER
 377 #define MULTIPLIER  int         /* type for fastest integer multiply */
 378 #endif
 379
 380
 381 /* FAST_FLOAT should be either float or double, whichever is done faster
 382  * by your compiler.  (Note that this type is only used in the floating point
 383  * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
 384  * Typically, float is faster in ANSI C compilers, while double is faster in
 385  * pre-ANSI compilers (because they insist on converting to double anyway).
 386  * The code below therefore chooses float if we have ANSI-style prototypes.
 387  */
 388
 389 #ifndef FAST_FLOAT
 390 #ifdef HAVE_PROTOTYPES
 391 #define FAST_FLOAT  float
 392 #else
 393 #define FAST_FLOAT  double
 394 #endif
 395 #endif
 396
 397 #endif /* JPEG_INTERNAL_OPTIONS */