src/jpeg/jmorecfg.h

/*
 * 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

#if defined( __GNUWIN32__ ) || defined( __MINGW32__ ) || defined( __CYGWIN__ )
#include <wx/msw/gccpriv.h>
#else
#undef wxCHECK_W32API_VERSION
#define wxCHECK_W32API_VERSION(maj, min) (0)
#endif

/* INT32 must hold at least signed 32-bit values. */

/* you may define INT32_DEFINED if it is already defined somewhere */
#ifndef INT32_DEFINED
#ifdef XMD_H
/* X11/xmd.h correctly defines INT32 */
#define INT32_DEFINED
#elif (_MSC_VER >= 1200) || (__BORLANDC__ >= 0x550) \
      || wxCHECK_W32API_VERSION( 0, 5 ) \
      || ((defined(__MINGW32__) || defined(__CYGWIN__)) \
      && ((__GNUC__>2) || ((__GNUC__==2) && (__GNUC_MINOR__>95)))) \
      || (defined(__MWERKS__) && defined(__WXMSW__))

/* INT32 is defined in windows.h  for these compilers */
#define INT32_DEFINED
#include <windows.h>
#endif
#endif /* !INT32_DEFINED */

#ifndef INT32_DEFINED
typedef long INT32;
#endif

#undef INT32_DEFINED

/* 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.
 */

#if defined(__VISAGECPP__) /* need this for /common/imagjpeg.obj but not loclly */
/* a function called through method pointers: */
#define METHODDEF(type)		static type _Optlink
/* a function used only in its module: */
#define LOCAL(type)		static type _Optlink
/* a function referenced thru EXTERNs: */
#define GLOBAL(type)		type
/* a reference to a GLOBAL function: */
#define EXTERN(type)		extern type _Optlink
#else
/* 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
#endif

/* 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.
 */

#if defined(__VISAGECPP__) /* need this for /common/imagjpeg.obj but not loclly */
#ifdef HAVE_PROTOTYPES
#define JMETHOD(type,methodname,arglist)  type (_Optlink *methodname) arglist
#else
#define JMETHOD(type,methodname,arglist)  type (_Optlink *methodname) ()
#endif

#else

#ifdef HAVE_PROTOTYPES
#define JMETHOD(type,methodname,arglist)  type (*methodname) arglist
#else
#define JMETHOD(type,methodname,arglist)  type (*methodname) ()
#endif

#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.
 */

#ifdef NEED_FAR_POINTERS
#define FAR  far
#else
#ifndef FAR
#define FAR
#endif
#endif


#if (defined(__MWERKS__) && defined(__WXMSW__))
#define HAVE_BOOLEAN
#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 */
#define DCT_FLOAT_SUPPORTED	/* floating-point: accurate, fast on fast HW */

/* Encoder capability options: */

#undef  C_ARITH_CODING_SUPPORTED    /* Arithmetic coding back end? */
#define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
#define C_PROGRESSIVE_SUPPORTED	    /* Progressive JPEG? (Requires MULTISCAN)*/
#define 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.)
 */
#define 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)*/
#define SAVE_MARKERS_SUPPORTED	    /* jpeg_save_markers() needed? */
#define BLOCK_SMOOTHING_SUPPORTED   /* Block smoothing? (Progressive only) */
#define IDCT_SCALING_SUPPORTED	    /* Output rescaling via IDCT? */
#undef  UPSAMPLE_SCALING_SUPPORTED  /* Output rescaling at upsample stage? */
#define UPSAMPLE_MERGING_SUPPORTED  /* Fast path for sloppy upsampling? */
#define QUANT_1PASS_SUPPORTED	    /* 1-pass color quantization? */
#define 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
#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 */
Commit	Line	Data
	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	#if defined( __GNUWIN32__ ) \|\| defined( __MINGW32__ ) \|\| defined( __CYGWIN__ )
	159	#include <wx/msw/gccpriv.h>
	160	#else
	161	#undef wxCHECK_W32API_VERSION
	162	#define wxCHECK_W32API_VERSION(maj, min) (0)
	163	#endif
	164
	165	/* INT32 must hold at least signed 32-bit values. */
	166
	167	/* you may define INT32_DEFINED if it is already defined somewhere */
	168	#ifndef INT32_DEFINED
	169	#ifdef XMD_H
	170	/* X11/xmd.h correctly defines INT32 */
	171	#define INT32_DEFINED
	172	#elif (_MSC_VER >= 1200) \|\| (__BORLANDC__ >= 0x550) \
	173	\|\| wxCHECK_W32API_VERSION( 0, 5 ) \
	174	\|\| ((defined(__MINGW32__) \|\| defined(__CYGWIN__)) \
	175	&& ((__GNUC__>2) \|\| ((__GNUC__==2) && (__GNUC_MINOR__>95)))) \
	176	\|\| (defined(__MWERKS__) && defined(__WXMSW__))
	177
	178	/* INT32 is defined in windows.h for these compilers */
	179	#define INT32_DEFINED
	180	#include <windows.h>
	181	#endif
	182	#endif /* !INT32_DEFINED */
	183
	184	#ifndef INT32_DEFINED
	185	typedef long INT32;
	186	#endif
	187
	188	#undef INT32_DEFINED
	189
	190	/* Datatype used for image dimensions. The JPEG standard only supports
	191	* images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
	192	* "unsigned int" is sufficient on all machines. However, if you need to
	193	* handle larger images and you don't mind deviating from the spec, you
	194	* can change this datatype.
	195	*/
	196
	197	typedef unsigned int JDIMENSION;
	198
	199	#define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
	200
	201
	202	/* These macros are used in all function definitions and extern declarations.
	203	* You could modify them if you need to change function linkage conventions;
	204	* in particular, you'll need to do that to make the library a Windows DLL.
	205	* Another application is to make all functions global for use with debuggers
	206	* or code profilers that require it.
	207	*/
	208
	209	#if defined(__VISAGECPP__) /* need this for /common/imagjpeg.obj but not loclly */
	210	/* a function called through method pointers: */
	211	#define METHODDEF(type) static type _Optlink
	212	/* a function used only in its module: */
	213	#define LOCAL(type) static type _Optlink
	214	/* a function referenced thru EXTERNs: */
	215	#define GLOBAL(type) type
	216	/* a reference to a GLOBAL function: */
	217	#define EXTERN(type) extern type _Optlink
	218	#else
	219	/* a function called through method pointers: */
	220	#define METHODDEF(type) static type
	221	/* a function used only in its module: */
	222	#define LOCAL(type) static type
	223	/* a function referenced thru EXTERNs: */
	224	#define GLOBAL(type) type
	225	/* a reference to a GLOBAL function: */
	226	#define EXTERN(type) extern type
	227	#endif
	228
	229	/* This macro is used to declare a "method", that is, a function pointer.
	230	* We want to supply prototype parameters if the compiler can cope.
	231	* Note that the arglist parameter must be parenthesized!
	232	* Again, you can customize this if you need special linkage keywords.
	233	*/
	234
	235	#if defined(__VISAGECPP__) /* need this for /common/imagjpeg.obj but not loclly */
	236	#ifdef HAVE_PROTOTYPES
	237	#define JMETHOD(type,methodname,arglist) type (_Optlink *methodname) arglist
	238	#else
	239	#define JMETHOD(type,methodname,arglist) type (_Optlink *methodname) ()
	240	#endif
	241
	242	#else
	243
	244	#ifdef HAVE_PROTOTYPES
	245	#define JMETHOD(type,methodname,arglist) type (*methodname) arglist
	246	#else
	247	#define JMETHOD(type,methodname,arglist) type (*methodname) ()
	248	#endif
	249
	250	#endif
	251
	252	/* Here is the pseudo-keyword for declaring pointers that must be "far"
	253	* on 80x86 machines. Most of the specialized coding for 80x86 is handled
	254	* by just saying "FAR *" where such a pointer is needed. In a few places
	255	* explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
	256	*/
	257
	258	#ifdef NEED_FAR_POINTERS
	259	#define FAR far
	260	#else
	261	#ifndef FAR
	262	#define FAR
	263	#endif
	264	#endif
	265
	266
	267	#if (defined(__MWERKS__) && defined(__WXMSW__))
	268	#define HAVE_BOOLEAN
	269	#endif
	270
	271	/*
	272	* On a few systems, type boolean and/or its values FALSE, TRUE may appear
	273	* in standard header files. Or you may have conflicts with application-
	274	* specific header files that you want to include together with these files.
	275	* Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
	276	*/
	277
	278	#ifndef HAVE_BOOLEAN
	279	typedef int boolean;
	280	#endif
	281	#ifndef FALSE /* in case these macros already exist */
	282	#define FALSE 0 /* values of boolean */
	283	#endif
	284	#ifndef TRUE
	285	#define TRUE 1
	286	#endif
	287
	288
	289	/*
	290	* The remaining options affect code selection within the JPEG library,
	291	* but they don't need to be visible to most applications using the library.
	292	* To minimize application namespace pollution, the symbols won't be
	293	* defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
	294	*/
	295
	296	#ifdef JPEG_INTERNALS
	297	#define JPEG_INTERNAL_OPTIONS
	298	#endif
	299
	300	#ifdef JPEG_INTERNAL_OPTIONS
	301
	302
	303	/*
	304	* These defines indicate whether to include various optional functions.
	305	* Undefining some of these symbols will produce a smaller but less capable
	306	* library. Note that you can leave certain source files out of the
	307	* compilation/linking process if you've #undef'd the corresponding symbols.
	308	* (You may HAVE to do that if your compiler doesn't like null source files.)
	309	*/
	310
	311	/* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */
	312
	313	/* Capability options common to encoder and decoder: */
	314
	315	#define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
	316	#define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
	317	#define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
	318
	319	/* Encoder capability options: */
	320
	321	#undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
	322	#define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
	323	#define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
	324	#define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
	325	/* Note: if you selected 12-bit data precision, it is dangerous to turn off
	326	* ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit
	327	* precision, so jchuff.c normally uses entropy optimization to compute
	328	* usable tables for higher precision. If you don't want to do optimization,
	329	* you'll have to supply different default Huffman tables.
	330	* The exact same statements apply for progressive JPEG: the default tables
	331	* don't work for progressive mode. (This may get fixed, however.)
	332	*/
	333	#define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
	334
	335	/* Decoder capability options: */
	336
	337	#undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
	338	#define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
	339	#define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
	340	#define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
	341	#define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
	342	#define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */
	343	#undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
	344	#define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
	345	#define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
	346	#define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
	347
	348	/* more capability options later, no doubt */
	349
	350
	351	/*
	352	* Ordering of RGB data in scanlines passed to or from the application.
	353	* If your application wants to deal with data in the order B,G,R, just
	354	* change these macros. You can also deal with formats such as R,G,B,X
	355	* (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
	356	* the offsets will also change the order in which colormap data is organized.
	357	* RESTRICTIONS:
	358	* 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
	359	* 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
	360	* useful if you are using JPEG color spaces other than YCbCr or grayscale.
	361	* 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
	362	* is not 3 (they don't understand about dummy color components!). So you
	363	* can't use color quantization if you change that value.
	364	*/
	365
	366	#define RGB_RED 0 /* Offset of Red in an RGB scanline element */
	367	#define RGB_GREEN 1 /* Offset of Green */
	368	#define RGB_BLUE 2 /* Offset of Blue */
	369	#define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */
	370
	371
	372	/* Definitions for speed-related optimizations. */
	373
	374
	375	/* If your compiler supports inline functions, define INLINE
	376	* as the inline keyword; otherwise define it as empty.
	377	*/
	378
	379	#ifndef INLINE
	380	#ifdef __GNUC__ /* for instance, GNU C knows about inline */
	381	#define INLINE __inline__
	382	#endif
	383	#ifndef INLINE
	384	#define INLINE /* default is to define it as empty */
	385	#endif
	386	#endif
	387
	388
	389	/* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
	390	* two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
	391	* as short on such a machine. MULTIPLIER must be at least 16 bits wide.
	392	*/
	393
	394	#ifndef MULTIPLIER
	395	#define MULTIPLIER int /* type for fastest integer multiply */
	396	#endif
	397
	398
	399	/* FAST_FLOAT should be either float or double, whichever is done faster
	400	* by your compiler. (Note that this type is only used in the floating point
	401	* DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
	402	* Typically, float is faster in ANSI C compilers, while double is faster in
	403	* pre-ANSI compilers (because they insist on converting to double anyway).
	404	* The code below therefore chooses float if we have ANSI-style prototypes.
	405	*/
	406
	407	#ifndef FAST_FLOAT
	408	#ifdef HAVE_PROTOTYPES
	409	#define FAST_FLOAT float
	410	#else
	411	#define FAST_FLOAT double
	412	#endif
	413	#endif
	414
	415	#endif /* JPEG_INTERNAL_OPTIONS */