1 /*
   2  * jmorecfg.h
   3  *
   4  * Copyright (C) 1991-1997, Thomas G. Lane.
   5  * Modified 1997-2009 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  *   12  for 12-bit sample values
  19  * Only 8 and 12 are legal data precisions for lossy JPEG according to the
  20  * JPEG standard, and the IJG code does not support anything else!
  21  * We do not support run-time selection of data precision, sorry.
  22  */
  23 
  24 #define BITS_IN_JSAMPLE  8	/* use 8 or 12 */
  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 #ifndef XMD_H			/* X11/xmd.h correctly defines INT32 */
 162 #ifndef _BASETSD_H_		/* Microsoft defines it in basetsd.h */
 163 #ifndef _BASETSD_H		/* MinGW is slightly different */
 164 #ifndef QGLOBAL_H		/* Qt defines it in qglobal.h */
 165 typedef long INT32;
 166 #endif
 167 #endif
 168 #endif
 169 #endif
 170 
 171 /* Datatype used for image dimensions.  The JPEG standard only supports
 172  * images up to 64K*64K due to 16-bit fields in SOF markers.  Therefore
 173  * "unsigned int" is sufficient on all machines.  However, if you need to
 174  * handle larger images and you don't mind deviating from the spec, you
 175  * can change this datatype.
 176  */
 177 
 178 typedef unsigned int JDIMENSION;
 179 
 180 #define JPEG_MAX_DIMENSION  65500L  /* a tad under 64K to prevent overflows */
 181 
 182 
 183 /* These macros are used in all function definitions and extern declarations.
 184  * You could modify them if you need to change function linkage conventions;
 185  * in particular, you'll need to do that to make the library a Windows DLL.
 186  * Another application is to make all functions global for use with debuggers
 187  * or code profilers that require it.
 188  */
 189 
 190 /* a function called through method pointers: */
 191 #define METHODDEF(type)		static type
 192 /* a function used only in its module: */
 193 #define LOCAL(type)		static type
 194 /* a function referenced thru EXTERNs: */
 195 /*#define GLOBAL(type)		type*/
 196 /* a reference to a GLOBAL function: */
 197 /*#define EXTERN(type)		extern type*/
 198 
 199 #if (!defined(_MSC_VER) || defined(JPEG_STATIC))
 200 #define GLOBAL(type)		type
 201 #define EXTERN(type)		extern type
 202 #else
 203 #ifdef JPEG_DLL_EXPORTS
 204 #define GLOBAL(type)		__declspec(dllexport) type
 205 #define EXTERN(type)		extern __declspec(dllexport) type
 206 #else
 207 #define GLOBAL(type)		__declspec(dllimport) type
 208 #define EXTERN(type)		extern __declspec(dllimport) type
 209 #endif
 210 #endif
 211 
 212 
 213 /* This macro is used to declare a "method", that is, a function pointer.
 214  * We want to supply prototype parameters if the compiler can cope.
 215  * Note that the arglist parameter must be parenthesized!
 216  * Again, you can customize this if you need special linkage keywords.
 217  */
 218 
 219 #ifdef HAVE_PROTOTYPES
 220 #define JMETHOD(type,methodname,arglist)  type (*methodname) arglist
 221 #else
 222 #define JMETHOD(type,methodname,arglist)  type (*methodname) ()
 223 #endif
 224 
 225 
 226 /* Here is the pseudo-keyword for declaring pointers that must be "far"
 227  * on 80x86 machines.  Most of the specialized coding for 80x86 is handled
 228  * by just saying "FAR *" where such a pointer is needed.  In a few places
 229  * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
 230  */
 231 
 232 #ifndef FAR
 233 #ifdef NEED_FAR_POINTERS
 234 #define FAR  far
 235 #else
 236 #define FAR
 237 #endif
 238 #endif
 239 
 240 
 241 /*
 242  * On a few systems, type boolean and/or its values FALSE, TRUE may appear
 243  * in standard header files.  Or you may have conflicts with application-
 244  * specific header files that you want to include together with these files.
 245  * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
 246  */
 247 
 248 #ifndef HAVE_BOOLEAN
 249 typedef int boolean;
 250 #endif
 251 #ifndef FALSE			/* in case these macros already exist */
 252 #define FALSE	0		/* values of boolean */
 253 #endif
 254 #ifndef TRUE
 255 #define TRUE	1
 256 #endif
 257 
 258 
 259 /*
 260  * The remaining options affect code selection within the JPEG library,
 261  * but they don't need to be visible to most applications using the library.
 262  * To minimize application namespace pollution, the symbols won't be
 263  * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
 264  */
 265 
 266 #ifdef JPEG_INTERNALS
 267 #define JPEG_INTERNAL_OPTIONS
 268 #endif
 269 
 270 #ifdef JPEG_INTERNAL_OPTIONS
 271 
 272 
 273 /*
 274  * These defines indicate whether to include various optional functions.
 275  * Undefining some of these symbols will produce a smaller but less capable
 276  * library.  Note that you can leave certain source files out of the
 277  * compilation/linking process if you've #undef'd the corresponding symbols.
 278  * (You may HAVE to do that if your compiler doesn't like null source files.)
 279  */
 280 
 281 /* Capability options common to encoder and decoder: */
 282 
 283 #define DCT_ISLOW_SUPPORTED	/* slow but accurate integer algorithm */
 284 #define DCT_IFAST_SUPPORTED	/* faster, less accurate integer method */
 285 #define DCT_FLOAT_SUPPORTED	/* floating-point: accurate, fast on fast HW */
 286 
 287 /* Encoder capability options: */
 288 
 289 #define C_ARITH_CODING_SUPPORTED    /* Arithmetic coding back end? */
 290 #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
 291 #define C_PROGRESSIVE_SUPPORTED	    /* Progressive JPEG? (Requires MULTISCAN)*/
 292 #define DCT_SCALING_SUPPORTED	    /* Input rescaling via DCT? (Requires DCT_ISLOW)*/
 293 #define ENTROPY_OPT_SUPPORTED	    /* Optimization of entropy coding parms? */
 294 /* Note: if you selected 12-bit data precision, it is dangerous to turn off
 295  * ENTROPY_OPT_SUPPORTED.  The standard Huffman tables are only good for 8-bit
 296  * precision, so jchuff.c normally uses entropy optimization to compute
 297  * usable tables for higher precision.  If you don't want to do optimization,
 298  * you'll have to supply different default Huffman tables.
 299  * The exact same statements apply for progressive JPEG: the default tables
 300  * don't work for progressive mode.  (This may get fixed, however.)
 301  */
 302 #define INPUT_SMOOTHING_SUPPORTED   /* Input image smoothing option? */
 303 
 304 /* Decoder capability options: */
 305 
 306 #define D_ARITH_CODING_SUPPORTED    /* Arithmetic coding back end? */
 307 #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
 308 #define D_PROGRESSIVE_SUPPORTED	    /* Progressive JPEG? (Requires MULTISCAN)*/
 309 #define IDCT_SCALING_SUPPORTED	    /* Output rescaling via IDCT? */
 310 #define SAVE_MARKERS_SUPPORTED	    /* jpeg_save_markers() needed? */
 311 #define BLOCK_SMOOTHING_SUPPORTED   /* Block smoothing? (Progressive only) */
 312 #undef  UPSAMPLE_SCALING_SUPPORTED  /* Output rescaling at upsample stage? */
 313 #define UPSAMPLE_MERGING_SUPPORTED  /* Fast path for sloppy upsampling? */
 314 #define QUANT_1PASS_SUPPORTED	    /* 1-pass color quantization? */
 315 #define QUANT_2PASS_SUPPORTED	    /* 2-pass color quantization? */
 316 
 317 /* more capability options later, no doubt */
 318 
 319 
 320 /*
 321  * Ordering of RGB data in scanlines passed to or from the application.
 322  * If your application wants to deal with data in the order B,G,R, just
 323  * change these macros.  You can also deal with formats such as R,G,B,X
 324  * (one extra byte per pixel) by changing RGB_PIXELSIZE.  Note that changing
 325  * the offsets will also change the order in which colormap data is organized.
 326  * RESTRICTIONS:
 327  * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
 328  * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
 329  *    useful if you are using JPEG color spaces other than YCbCr or grayscale.
 330  * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
 331  *    is not 3 (they don't understand about dummy color components!).  So you
 332  *    can't use color quantization if you change that value.
 333  */
 334 
 335 #define RGB_RED		0	/* Offset of Red in an RGB scanline element */
 336 #define RGB_GREEN	1	/* Offset of Green */
 337 #define RGB_BLUE	2	/* Offset of Blue */
 338 #define RGB_PIXELSIZE	3	/* JSAMPLEs per RGB scanline element */
 339 
 340 
 341 /* Definitions for speed-related optimizations. */
 342 
 343 
 344 /* If your compiler supports inline functions, define INLINE
 345  * as the inline keyword; otherwise define it as empty.
 346  */
 347 
 348 #ifndef INLINE
 349 #ifdef __GNUC__			/* for instance, GNU C knows about inline */
 350 #define INLINE __inline__
 351 #endif
 352 #ifndef INLINE
 353 #define INLINE			/* default is to define it as empty */
 354 #endif
 355 #endif
 356 
 357 
 358 /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
 359  * two 16-bit shorts is faster than multiplying two ints.  Define MULTIPLIER
 360  * as short on such a machine.  MULTIPLIER must be at least 16 bits wide.
 361  */
 362 
 363 #ifndef MULTIPLIER
 364 #define MULTIPLIER  int		/* type for fastest integer multiply */
 365 #endif
 366 
 367 
 368 /* FAST_FLOAT should be either float or double, whichever is done faster
 369  * by your compiler.  (Note that this type is only used in the floating point
 370  * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
 371  * Typically, float is faster in ANSI C compilers, while double is faster in
 372  * pre-ANSI compilers (because they insist on converting to double anyway).
 373  * The code below therefore chooses float if we have ANSI-style prototypes.
 374  */
 375 
 376 #ifndef FAST_FLOAT
 377 #ifdef HAVE_PROTOTYPES
 378 #define FAST_FLOAT  float
 379 #else
 380 #define FAST_FLOAT  double
 381 #endif
 382 #endif
 383 
 384 #endif /* JPEG_INTERNAL_OPTIONS */
 385