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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. |
*/ |
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/* |
* 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. |
*/ |
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#define BITS_IN_JSAMPLE 8 /* use 8 or 12 */ |
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/* |
* 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.) |
*/ |
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#define MAX_COMPONENTS 10 /* maximum number of image components */ |
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/* |
* 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. |
*/ |
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/* 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. |
*/ |
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#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. |
*/ |
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#ifdef HAVE_UNSIGNED_CHAR |
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typedef unsigned char JSAMPLE; |
#define GETJSAMPLE(value) ((int) (value)) |
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#else /* not HAVE_UNSIGNED_CHAR */ |
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typedef char JSAMPLE; |
#ifdef CHAR_IS_UNSIGNED |
#define GETJSAMPLE(value) ((int) (value)) |
#else |
#define GETJSAMPLE(value) ((int) (value) & 0xFF) |
#endif /* CHAR_IS_UNSIGNED */ |
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#endif /* HAVE_UNSIGNED_CHAR */ |
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#define MAXJSAMPLE 255 |
#define CENTERJSAMPLE 128 |
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#endif /* BITS_IN_JSAMPLE == 8 */ |
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#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. |
*/ |
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typedef short JSAMPLE; |
#define GETJSAMPLE(value) ((int) (value)) |
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#define MAXJSAMPLE 4095 |
#define CENTERJSAMPLE 2048 |
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#endif /* BITS_IN_JSAMPLE == 12 */ |
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/* 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. |
*/ |
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typedef short JCOEF; |
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/* 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. |
*/ |
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#ifdef HAVE_UNSIGNED_CHAR |
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typedef unsigned char JOCTET; |
#define GETJOCTET(value) (value) |
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#else /* not HAVE_UNSIGNED_CHAR */ |
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typedef char JOCTET; |
#ifdef CHAR_IS_UNSIGNED |
#define GETJOCTET(value) (value) |
#else |
#define GETJOCTET(value) ((value) & 0xFF) |
#endif /* CHAR_IS_UNSIGNED */ |
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#endif /* HAVE_UNSIGNED_CHAR */ |
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/* 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.) |
*/ |
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/* UINT8 must hold at least the values 0..255. */ |
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#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 */ |
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/* UINT16 must hold at least the values 0..65535. */ |
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#ifdef HAVE_UNSIGNED_SHORT |
typedef unsigned short UINT16; |
#else /* not HAVE_UNSIGNED_SHORT */ |
typedef unsigned int UINT16; |
#endif /* HAVE_UNSIGNED_SHORT */ |
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/* INT16 must hold at least the values -32768..32767. */ |
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#ifndef XMD_H /* X11/xmd.h correctly defines INT16 */ |
typedef short INT16; |
#endif |
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/* INT32 must hold at least signed 32-bit values. */ |
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#ifndef XMD_H /* X11/xmd.h correctly defines INT32 */ |
typedef long INT32; |
#endif |
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/* 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. |
*/ |
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typedef unsigned int JDIMENSION; |
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#define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */ |
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/* 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. |
*/ |
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/* 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 |
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/* 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. |
*/ |
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#ifdef HAVE_PROTOTYPES |
#define JMETHOD(type,methodname,arglist) type (*methodname) arglist |
#else |
#define JMETHOD(type,methodname,arglist) type (*methodname) () |
#endif |
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/* 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. |
*/ |
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#ifdef NEED_FAR_POINTERS |
#define FAR far |
#else |
#define FAR |
#endif |
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/* |
* 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. |
*/ |
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#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 |
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/* |
* 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. |
*/ |
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#ifdef JPEG_INTERNALS |
#define JPEG_INTERNAL_OPTIONS |
#endif |
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#ifdef JPEG_INTERNAL_OPTIONS |
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/* |
* 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.) |
*/ |
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/* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */ |
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/* Capability options common to encoder and decoder: */ |
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#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 */ |
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/* Encoder capability options: */ |
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#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? */ |
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/* Decoder capability options: */ |
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#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? */ |
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/* more capability options later, no doubt */ |
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/* |
* 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. |
*/ |
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#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 */ |
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/* Definitions for speed-related optimizations. */ |
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/* If your compiler supports inline functions, define INLINE |
* as the inline keyword; otherwise define it as empty. |
*/ |
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#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 |
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/* 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. |
*/ |
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#ifndef MULTIPLIER |
#define MULTIPLIER int /* type for fastest integer multiply */ |
#endif |
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/* 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. |
*/ |
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#ifndef FAST_FLOAT |
#ifdef HAVE_PROTOTYPES |
#define FAST_FLOAT float |
#else |
#define FAST_FLOAT double |
#endif |
#endif |
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#endif /* JPEG_INTERNAL_OPTIONS */ |