jmorecfg.h
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- /*
- * jmorecfg.h
- *
- * Copyright (C) 1991-1997, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
- *
- * This file contains additional configuration options that customize the
- * JPEG software for special applications or support machine-dependent
- * optimizations. Most users will not need to touch this file.
- */
- /*
- * Define BITS_IN_JSAMPLE as either
- * 8 for 8-bit sample values (the usual setting)
- * 12 for 12-bit sample values
- * Only 8 and 12 are legal data precisions for lossy JPEG according to the
- * JPEG standard, and the IJG code does not support anything else!
- * We do not support run-time selection of data precision, sorry.
- */
- #define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
- /*
- * Maximum number of components (color channels) allowed in JPEG image.
- * To meet the letter of the JPEG spec, set this to 255. However, darn
- * few applications need more than 4 channels (maybe 5 for CMYK + alpha
- * mask). We recommend 10 as a reasonable compromise; use 4 if you are
- * really short on memory. (Each allowed component costs a hundred or so
- * bytes of storage, whether actually used in an image or not.)
- */
- #define MAX_COMPONENTS 10 /* maximum number of image components */
- /*
- * Basic data types.
- * You may need to change these if you have a machine with unusual data
- * type sizes; for example, "char" not 8 bits, "short" not 16 bits,
- * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits,
- * but it had better be at least 16.
- */
- /* Representation of a single sample (pixel element value).
- * We frequently allocate large arrays of these, so it's important to keep
- * them small. But if you have memory to burn and access to char or short
- * arrays is very slow on your hardware, you might want to change these.
- */
- #if BITS_IN_JSAMPLE == 8
- /* JSAMPLE should be the smallest type that will hold the values 0..255.
- * You can use a signed char by having GETJSAMPLE mask it with 0xFF.
- */
- #ifdef HAVE_UNSIGNED_CHAR
- typedef unsigned char JSAMPLE;
- #define GETJSAMPLE(value) ((int) (value))
- #else /* not HAVE_UNSIGNED_CHAR */
- typedef char JSAMPLE;
- #ifdef CHAR_IS_UNSIGNED
- #define GETJSAMPLE(value) ((int) (value))
- #else
- #define GETJSAMPLE(value) ((int) (value) & 0xFF)
- #endif /* CHAR_IS_UNSIGNED */
- #endif /* HAVE_UNSIGNED_CHAR */
- #define MAXJSAMPLE 255
- #define CENTERJSAMPLE 128
- #endif /* BITS_IN_JSAMPLE == 8 */
- #if BITS_IN_JSAMPLE == 12
- /* JSAMPLE should be the smallest type that will hold the values 0..4095.
- * On nearly all machines "short" will do nicely.
- */
- typedef short JSAMPLE;
- #define GETJSAMPLE(value) ((int) (value))
- #define MAXJSAMPLE 4095
- #define CENTERJSAMPLE 2048
- #endif /* BITS_IN_JSAMPLE == 12 */
- /* Representation of a DCT frequency coefficient.
- * This should be a signed value of at least 16 bits; "short" is usually OK.
- * Again, we allocate large arrays of these, but you can change to int
- * if you have memory to burn and "short" is really slow.
- */
- typedef short JCOEF;
- /* Compressed datastreams are represented as arrays of JOCTET.
- * These must be EXACTLY 8 bits wide, at least once they are written to
- * external storage. Note that when using the stdio data source/destination
- * managers, this is also the data type passed to fread/fwrite.
- */
- #ifdef HAVE_UNSIGNED_CHAR
- typedef unsigned char JOCTET;
- #define GETJOCTET(value) (value)
- #else /* not HAVE_UNSIGNED_CHAR */
- typedef char JOCTET;
- #ifdef CHAR_IS_UNSIGNED
- #define GETJOCTET(value) (value)
- #else
- #define GETJOCTET(value) ((value) & 0xFF)
- #endif /* CHAR_IS_UNSIGNED */
- #endif /* HAVE_UNSIGNED_CHAR */
- /* These typedefs are used for various table entries and so forth.
- * They must be at least as wide as specified; but making them too big
- * won't cost a huge amount of memory, so we don't provide special
- * extraction code like we did for JSAMPLE. (In other words, these
- * typedefs live at a different point on the speed/space tradeoff curve.)
- */
- /* UINT8 must hold at least the values 0..255. */
- #ifdef HAVE_UNSIGNED_CHAR
- typedef unsigned char UINT8;
- #else /* not HAVE_UNSIGNED_CHAR */
- #ifdef CHAR_IS_UNSIGNED
- typedef char UINT8;
- #else /* not CHAR_IS_UNSIGNED */
- typedef short UINT8;
- #endif /* CHAR_IS_UNSIGNED */
- #endif /* HAVE_UNSIGNED_CHAR */
- /* UINT16 must hold at least the values 0..65535. */
- #ifdef HAVE_UNSIGNED_SHORT
- typedef unsigned short UINT16;
- #else /* not HAVE_UNSIGNED_SHORT */
- typedef unsigned int UINT16;
- #endif /* HAVE_UNSIGNED_SHORT */
- /* INT16 must hold at least the values -32768..32767. */
- #ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
- typedef short INT16;
- #endif
- /* INT32 must hold at least signed 32-bit values. */
- #if !defined(_BASETSD_H_) && !defined(_TYPES_H_) && !defined(XMD_H)
- typedef long INT32;
- #endif
- /* Datatype used for image dimensions. The JPEG standard only supports
- * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
- * "unsigned int" is sufficient on all machines. However, if you need to
- * handle larger images and you don't mind deviating from the spec, you
- * can change this datatype.
- */
- typedef unsigned int JDIMENSION;
- #define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
- /* These macros are used in all function definitions and extern declarations.
- * You could modify them if you need to change function linkage conventions;
- * in particular, you'll need to do that to make the library a Windows DLL.
- * Another application is to make all functions global for use with debuggers
- * or code profilers that require it.
- */
- /* a function called through method pointers: */
- #define METHODDEF(type) static type
- /* a function used only in its module: */
- #define LOCAL(type) static type
- /* a function referenced thru EXTERNs: */
- #define GLOBAL(type) type
- /* a reference to a GLOBAL function: */
- #define EXTERN(type) extern type
- /* This macro is used to declare a "method", that is, a function pointer.
- * We want to supply prototype parameters if the compiler can cope.
- * Note that the arglist parameter must be parenthesized!
- * Again, you can customize this if you need special linkage keywords.
- */
- #ifdef HAVE_PROTOTYPES
- #define JMETHOD(type,methodname,arglist) type (*methodname) arglist
- #else
- #define JMETHOD(type,methodname,arglist) type (*methodname) ()
- #endif
- /* Here is the pseudo-keyword for declaring pointers that must be "far"
- * on 80x86 machines. Most of the specialized coding for 80x86 is handled
- * by just saying "FAR *" where such a pointer is needed. In a few places
- * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
- */
- #ifndef FAR
- #ifdef NEED_FAR_POINTERS
- #define FAR far
- #else
- #define FAR
- #endif
- #endif
- /*
- * On a few systems, type boolean and/or its values FALSE, TRUE may appear
- * in standard header files. Or you may have conflicts with application-
- * specific header files that you want to include together with these files.
- * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
- */
- #ifndef HAVE_BOOLEAN
- typedef int boolean;
- #endif
- #ifndef FALSE /* in case these macros already exist */
- #define FALSE 0 /* values of boolean */
- #endif
- #ifndef TRUE
- #define TRUE 1
- #endif
- /*
- * The remaining options affect code selection within the JPEG library,
- * but they don't need to be visible to most applications using the library.
- * To minimize application namespace pollution, the symbols won't be
- * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
- */
- #ifdef JPEG_INTERNALS
- #define JPEG_INTERNAL_OPTIONS
- #endif
- #ifdef JPEG_INTERNAL_OPTIONS
- /*
- * These defines indicate whether to include various optional functions.
- * Undefining some of these symbols will produce a smaller but less capable
- * library. Note that you can leave certain source files out of the
- * compilation/linking process if you've #undef'd the corresponding symbols.
- * (You may HAVE to do that if your compiler doesn't like null source files.)
- */
- /* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */
- /* Capability options common to encoder and decoder: */
- #define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
- #define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
- #undef DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
- /* Encoder capability options: */
- #undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
- #undef C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
- #undef C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
- #undef ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
- /* Note: if you selected 12-bit data precision, it is dangerous to turn off
- * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit
- * precision, so jchuff.c normally uses entropy optimization to compute
- * usable tables for higher precision. If you don't want to do optimization,
- * you'll have to supply different default Huffman tables.
- * The exact same statements apply for progressive JPEG: the default tables
- * don't work for progressive mode. (This may get fixed, however.)
- */
- #undef INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
- /* Decoder capability options: */
- #undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
- #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
- #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
- #undef SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
- #undef BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
- #define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */
- #define UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
- #define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
- #undef QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
- #undef QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
- /* more capability options later, no doubt */
- /*
- * Ordering of RGB data in scanlines passed to or from the application.
- * If your application wants to deal with data in the order B,G,R, just
- * change these macros. You can also deal with formats such as R,G,B,X
- * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
- * the offsets will also change the order in which colormap data is organized.
- * RESTRICTIONS:
- * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
- * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
- * useful if you are using JPEG color spaces other than YCbCr or grayscale.
- * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
- * is not 3 (they don't understand about dummy color components!). So you
- * can't use color quantization if you change that value.
- */
- #define RGB_RED 0 /* Offset of Red in an RGB scanline element */
- #define RGB_GREEN 1 /* Offset of Green */
- #define RGB_BLUE 2 /* Offset of Blue */
- #define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */
- /* Definitions for speed-related optimizations. */
- /* If your compiler supports inline functions, define INLINE
- * as the inline keyword; otherwise define it as empty.
- */
- #ifndef INLINE
- #ifdef __GNUC__ /* for instance, GNU C knows about inline */
- #define INLINE __inline__
- #endif
- #define INLINE inline
- #ifndef INLINE
- #define INLINE /* default is to define it as empty */
- #endif
- #endif
- /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
- * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
- * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
- */
- #ifndef MULTIPLIER
- #define MULTIPLIER int /* type for fastest integer multiply */
- #endif
- /* FAST_FLOAT should be either float or double, whichever is done faster
- * by your compiler. (Note that this type is only used in the floating point
- * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
- * Typically, float is faster in ANSI C compilers, while double is faster in
- * pre-ANSI compilers (because they insist on converting to double anyway).
- * The code below therefore chooses float if we have ANSI-style prototypes.
- */
- #ifndef FAST_FLOAT
- #ifdef HAVE_PROTOTYPES
- #define FAST_FLOAT float
- #else
- #define FAST_FLOAT double
- #endif
- #endif
- #endif /* JPEG_INTERNAL_OPTIONS */