1 +lY>ji?u@3q.1h߿ L_I|+7/* * jmorecfg.h * * This file was part of the Independent JPEG Group's software: * Copyright (C) 1991-1997, Thomas G. Lane. * Modified 1997-2009 by Guido Vollbeding. * libjpeg-turbo Modifications: * Copyright (C) 2009, 2011, 2014-2015, 2018, 2020, D. R. Commander. * For conditions of distribution and use, see the accompanying README.ijg * 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. */ /* * Maximum number of components (color channels) allowed in JPEG image. * To meet the letter of Rec. ITU-T T.81 | ISO/IEC 10918-1, 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. */ typedef unsigned char JSAMPLE; #define GETJSAMPLE(value) ((int)(value)) #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. */ typedef unsigned char JOCTET; #define GETJOCTET(value) (value) /* 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; /* 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 /* INT32 must hold at least signed 32-bit values. * * NOTE: The INT32 typedef dates back to libjpeg v5 (1994.) Integers were * sometimes 16-bit back then (MS-DOS), which is why INT32 is typedef'd to * long. It also wasn't common (or at least as common) in 1994 for INT32 to be * defined by platform headers. Since then, however, INT32