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* jmorecfg.h
* Copyright (C) 1991-1997, Thomas G. Lane.
* Copyright (C) 2009, D. R. Commander.
* 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.
* When we're building for android, turn on ANDROID_RGB by default.
* This is needed for components like skia which make use of the
* new encodings defined behind ANDROID_RBG. It's not a reasonable
* config to have ANDROID_RBG off.
#ifdef ANDROID
* 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.
/* 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.
typedef unsigned char JSAMPLE;
#define GETJSAMPLE(value) ((int) (value))
#else /* not HAVE_UNSIGNED_CHAR */
typedef char JSAMPLE;
#ifdef __CHAR_UNSIGNED__
#define GETJSAMPLE(value) ((int) (value))
#define GETJSAMPLE(value) ((int) (value) & 0xFF)
#endif /* __CHAR_UNSIGNED__ */
#define MAXJSAMPLE 255
#endif /* BITS_IN_JSAMPLE == 8 */
/* 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.
typedef unsigned char JOCTET;
#define GETJOCTET(value) (value)
#else /* not HAVE_UNSIGNED_CHAR */
typedef char JOCTET;
#ifdef __CHAR_UNSIGNED__
#define GETJOCTET(value) (value)
#define GETJOCTET(value) ((value) & 0xFF)
#endif /* __CHAR_UNSIGNED__ */
/* 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. */
typedef unsigned char UINT8;
#else /* not HAVE_UNSIGNED_CHAR */
#ifdef __CHAR_UNSIGNED__
typedef char UINT8;
#else /* not __CHAR_UNSIGNED__ */
typedef short UINT8;
#endif /* __CHAR_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 at least signed 32-bit values. */
#ifndef XMD_H /* X11/xmd.h correctly defines INT32 */
typedef long INT32;
/* 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.
#define JMETHOD(type,methodname,arglist) type (*methodname) arglist
#define JMETHOD(type,methodname,arglist) type (*methodname) ()
/* 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.
#define FAR far
#define FAR
* 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.
typedef int boolean;
#ifndef FALSE /* in case these macros already exist */
#define FALSE 0 /* values of boolean */
#ifndef TRUE
#define TRUE 1
* 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.
* 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.)
/* 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: */
#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: */
#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.
* 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 */
#define RGB_ALPHA 3 /* Offset of Alpha */
#define JPEG_NUMCS 12
static const int rgb_red[JPEG_NUMCS] = {
-1, -1, RGB_RED, -1, -1, -1, 0, 0, 2, 2, 3, 1
static const int rgb_green[JPEG_NUMCS] = {
-1, -1, RGB_GREEN, -1, -1, -1, 1, 1, 1, 1, 2, 2
static const int rgb_blue[JPEG_NUMCS] = {
-1, -1, RGB_BLUE, -1, -1, -1, 2, 2, 0, 0, 1, 3
static const int rgb_pixelsize[JPEG_NUMCS] = {
-1, -1, RGB_PIXELSIZE, -1, -1, -1, 3, 4, 3, 4, 4, 4
* Define ANDROID_RGB to enable specific optimizations for Android
* JCS_RGBA_8888 support
* JCS_RGB_565 support
#define PACK_SHORT_565(r,g,b) ((((r)<<8)&0xf800)|(((g)<<3)&0x7E0)|((b)>>3))
#define PACK_TWO_PIXELS(l,r) ((r<<16) | l)
#define PACK_NEED_ALIGNMENT(ptr) (((int)(ptr))&3)
#define WRITE_TWO_PIXELS(addr, pixels) do { \
((INT16*)(addr))[0] = (pixels); \
((INT16*)(addr))[1] = (pixels)>>16; \
} while(0)
#define WRITE_TWO_ALIGNED_PIXELS(addr, pixels) ((*(INT32*)(addr)) = pixels)
#define DITHER_565_R(r, dither) ((r) + ((dither)&0xFF))
#define DITHER_565_G(g, dither) ((g) + (((dither)&0xFF)>>1))
#define DITHER_565_B(b, dither) ((b) + ((dither)&0xFF))
/* Definitions for speed-related optimizations. */
/* 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 WITH_SIMD
#define MULTIPLIER int /* type for fastest integer multiply */
#define MULTIPLIER short /* prefer 16-bit with SIMD for parellelism */
/* 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
#define FAST_FLOAT float
#define FAST_FLOAT double
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