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* jconfig.h
* Copyright (C) 1991, 1992, 1993, 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 preprocessor declarations that help customize
* the JPEG software for a particular application, machine, or compiler.
* Edit these declarations as needed (or add -D flags to the Makefile).
* These symbols indicate the properties of your machine or compiler.
* The conditional definitions given may do the right thing already,
* but you'd best look them over closely, especially if your compiler
* does not handle full ANSI C. An ANSI-compliant C compiler should
* provide all the necessary features; __STDC__ is supposed to be
* predefined by such compilers.
* HAVE_STDC is tested below to see whether ANSI features are available.
* We avoid testing __STDC__ directly for arcane reasons of portability.
* (On some compilers, __STDC__ is only defined if a switch is given,
* but the switch also disables machine-specific features we need to get at.
* In that case, -DHAVE_STDC in the Makefile is a convenient solution.)
#ifdef __STDC__ /* if compiler claims to be ANSI, believe it */
#define HAVE_STDC
/* Does your compiler support function prototypes? */
/* (If not, you also need to use ansi2knr, see SETUP) */
#ifdef HAVE_STDC /* ANSI C compilers always have prototypes */
#define PROTO
#ifdef __cplusplus /* So do C++ compilers */
#define PROTO
/* Does your compiler support the declaration "unsigned char" ? */
/* How about "unsigned short" ? */
#ifdef HAVE_STDC /* ANSI C compilers must support both */
/* Define this if an ordinary "char" type is unsigned.
* If you're not sure, leaving it undefined will work at some cost in speed.
* If you defined HAVE_UNSIGNED_CHAR then it doesn't matter very much.
/* #define CHAR_IS_UNSIGNED */
/* Define this if your compiler implements ">>" on signed values as a logical
* (unsigned) shift; leave it undefined if ">>" is a signed (arithmetic) shift,
* which is the normal and rational definition.
/* Define "void" as "char" if your compiler doesn't know about type void.
* NOTE: be sure to define void such that "void *" represents the most general
* pointer type, e.g., that returned by malloc().
/* #define void char */
/* Define const as empty if your compiler doesn't know the "const" keyword. */
/* (Even if it does, defining const as empty won't break anything.) */
#ifndef HAVE_STDC /* ANSI C and C++ compilers should know it. */
#ifndef __cplusplus
#define const
/* For 80x86 machines, you need to define NEED_FAR_POINTERS,
* unless you are using a large-data memory model or 80386 flat-memory mode.
* On less brain-damaged CPUs this symbol must not be defined.
* (Defining this symbol causes large data structures to be referenced through
* "far" pointers and to be allocated with a special version of malloc.)
#ifdef MSDOS
/* The next three symbols only affect the system-dependent user interface
* modules (jcmain.c, jdmain.c). You can ignore these if you are supplying
* your own user interface code.
/* Define this if you want to name both input and output files on the command
* line, rather than using stdout and optionally stdin. You MUST do this if
* your system can't cope with binary I/O to stdin/stdout. See comments at
* head of jcmain.c or jdmain.c.
#ifdef MSDOS /* two-file style is needed for PCs */
#ifndef USE_FDOPEN /* unless you have fdopen() or setmode() */
#ifdef THINK_C /* it's needed for Macintosh too */
/* Define this if your system needs explicit cleanup of temporary files.
* This is crucial under MS-DOS, where the temporary "files" may be areas
* of extended memory; on most other systems it's not as important.
#ifdef MSDOS
/* By default, we open image files with fopen(...,"rb") or fopen(...,"wb").
* This is necessary on systems that distinguish text files from binary files,
* and is harmless on most systems that don't. If you have one of the rare
* systems that complains about the "b" spec, define this symbol.
/* #define DONT_USE_B_MODE */
/* If you're getting bored, that's the end of the symbols you HAVE to
* worry about. Go fix the makefile and compile.
/* If your compiler supports inline functions, define INLINE
* as the inline keyword; otherwise define it as empty.
#ifdef __GNUC__ /* for instance, GNU C knows about inline */
#define INLINE __inline__
#ifndef INLINE /* default is to define it as empty */
#define INLINE
/* On a few systems, type boolean and/or macros 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.
* In that case you need only comment out these definitions.
typedef int boolean;
#undef FALSE /* in case these macros already exist */
#undef TRUE
#define FALSE 0 /* values of boolean */
#define TRUE 1
/* This defines the size of the I/O buffers for entropy compression
* and decompression; you could reduce it if memory is tight.
#define JPEG_BUF_SIZE 4096 /* bytes */
/* These symbols determine the JPEG functionality supported. */
* These defines indicate whether to include various optional functions.
* Undefining some of these symbols will produce a smaller but less capable
* program file. 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. */
/* Encoder capability options: */
#undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
#undef C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? (NYI) */
#define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
#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 BLOCK_SMOOTHING_SUPPORTED /* Block smoothing during decoding? */
#define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
#define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
/* these defines indicate which JPEG file formats are allowed */
#define JFIF_SUPPORTED /* JFIF or "raw JPEG" files */
#undef JTIFF_SUPPORTED /* JPEG-in-TIFF (not yet implemented) */
/* these defines indicate which image (non-JPEG) file formats are allowed */
#define GIF_SUPPORTED /* GIF image file format */
/* #define RLE_SUPPORTED */ /* RLE image file format (by default, no) */
#define PPM_SUPPORTED /* PPM/PGM image file format */
#define TARGA_SUPPORTED /* Targa image file format */
#undef TIFF_SUPPORTED /* TIFF image file format (not yet impl.) */
/* more capability options later, no doubt */
* Define exactly one of these three symbols to indicate whether you want
* 8-bit, 12-bit, or 16-bit sample (pixel component) values. 8-bit is the
* default and is nearly always the right thing to use. You can use 12-bit if
* you need to support image formats with more than 8 bits of resolution in a
* color value. 16-bit should only be used for the lossless JPEG mode (not
* currently supported). Note that 12- and 16-bit values take up twice as
* much memory as 8-bit!
* Note: if you select 12- or 16-bit 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 remaining definitions don't need to be hand-edited in most cases.
* You may need to change these if you have a machine with unusual data
* types; 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.
/* First define the representation of a single pixel element value. */
/* 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.
* If you have only signed chars, and you are more worried about speed than
* memory usage, it might be a win to make JSAMPLE be short.
typedef unsigned char JSAMPLE;
#define GETJSAMPLE(value) (value)
#else /* not HAVE_UNSIGNED_CHAR */
typedef char JSAMPLE;
#define GETJSAMPLE(value) (value)
#else /* not CHAR_IS_UNSIGNED */
typedef char JSAMPLE;
#define GETJSAMPLE(value) ((value) & 0xFF)
#endif /* CHAR_IS_UNSIGNED */
#define MAXJSAMPLE 255
#endif /* EIGHT_BIT_SAMPLES */
/* 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) (value)
#define BITS_IN_JSAMPLE 12
#define MAXJSAMPLE 4095
#define CENTERJSAMPLE 2048
/* JSAMPLE should be the smallest type that will hold the values 0..65535. */
typedef unsigned short JSAMPLE;
#define GETJSAMPLE(value) (value)
#else /* not HAVE_UNSIGNED_SHORT */
/* If int is 32 bits this'll be horrendously inefficient storage-wise.
* But since we don't actually support 16-bit samples (ie lossless coding) yet,
* I'm not going to worry about making a smarter definition ...
typedef unsigned int JSAMPLE;
#define GETJSAMPLE(value) (value)
#define BITS_IN_JSAMPLE 16
#define MAXJSAMPLE 65535
#define CENTERJSAMPLE 32768
/* Here we define the representation of a DCT frequency coefficient.
* This should be a signed 16-bit value; "short" is usually right.
* It's important that this be exactly 16 bits, no more and no less;
* more will cost you a BIG hit of memory, less will give wrong answers.
typedef short JCOEF;
/* The remaining 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. */
typedef unsigned char UINT8;
#else /* not HAVE_UNSIGNED_CHAR */
typedef char UINT8;
#else /* not CHAR_IS_UNSIGNED */
typedef short UINT8;
#endif /* CHAR_IS_UNSIGNED */
/* UINT16 must hold at least the values 0..65535. */
typedef unsigned short UINT16;
#else /* not HAVE_UNSIGNED_SHORT */
typedef unsigned int UINT16;
/* INT16 must hold at least the values -32768..32767. */
#ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
typedef short INT16;
/* INT32 must hold signed 32-bit values; if your machine happens */
/* to have 64-bit longs, you might want to change this. */
#ifndef XMD_H /* X11/xmd.h correctly defines INT32 */
typedef long INT32;