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 */