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