19f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 29f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * jdct.h 39f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 49f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Copyright (C) 1994-1996, Thomas G. Lane. 59f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This file is part of the Independent JPEG Group's software. 69f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * For conditions of distribution and use, see the accompanying README file. 79f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 89f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This include file contains common declarations for the forward and 99f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * inverse DCT modules. These declarations are private to the DCT managers 109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms. 119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The individual DCT algorithms are kept in separate files to ease 129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * machine-dependent tuning (e.g., assembly coding). 139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * A forward DCT routine is given a pointer to a work area of type DCTELEM[]; 189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * the DCT is to be performed in-place in that buffer. Type DCTELEM is int 199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * for 8-bit samples, INT32 for 12-bit samples. (NOTE: Floating-point DCT 209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * implementations use an array of type FAST_FLOAT, instead.) 219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The DCT inputs are expected to be signed (range +-CENTERJSAMPLE). 229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The DCT outputs are returned scaled up by a factor of 8; they therefore 239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This 249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * convention improves accuracy in integer implementations and saves some 259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * work in floating-point ones. 269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Quantization of the output coefficients is done by jcdctmgr.c. 279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#if BITS_IN_JSAMPLE == 8 309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef int DCTELEM; /* 16 or 32 bits is fine */ 319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#else 329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef INT32 DCTELEM; /* must have 32 bits */ 339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data)); 369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data)); 379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer 419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * to an output sample array. The routine must dequantize the input data as 429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * well as perform the IDCT; for dequantization, it uses the multiplier table 439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * pointed to by compptr->dct_table. The output data is to be placed into the 449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * sample array starting at a specified column. (Any row offset needed will 459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * be applied to the array pointer before it is passed to the IDCT code.) 469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Note that the number of samples emitted by the IDCT routine is 479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * DCT_scaled_size * DCT_scaled_size. 489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* typedef inverse_DCT_method_ptr is declared in jpegint.h */ 519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Each IDCT routine has its own ideas about the best dct_table element type. 549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */ 579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#if BITS_IN_JSAMPLE == 8 589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */ 599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */ 609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#else 619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */ 629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */ 639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */ 659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Each IDCT routine is responsible for range-limiting its results and 699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could 709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * be quite far out of range if the input data is corrupt, so a bulletproof 719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * range-limiting step is required. We use a mask-and-table-lookup method 729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * to do the combined operations quickly. See the comments with 739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * prepare_range_limit_table (in jdmaster.c) for more info. 749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE) 779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */ 799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Short forms of external names for systems with brain-damaged linkers. */ 829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef NEED_SHORT_EXTERNAL_NAMES 849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_fdct_islow jFDislow 859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_fdct_ifast jFDifast 869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_fdct_float jFDfloat 879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_idct_islow jRDislow 889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_idct_ifast jRDifast 899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_idct_float jRDfloat 909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_idct_4x4 jRD4x4 919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_idct_2x2 jRD2x2 929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define jpeg_idct_1x1 jRD1x1 939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif /* NEED_SHORT_EXTERNAL_NAMES */ 949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Extern declarations for the forward and inverse DCT routines. */ 969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_fdct_islow JPP((DCTELEM * data)); 989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_fdct_ifast JPP((DCTELEM * data)); 999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_fdct_float JPP((FAST_FLOAT * data)); 1009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_idct_islow 1029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 1039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 1049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_idct_ifast 1059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 1069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 1079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_idct_float 1089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 1099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 1109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_idct_4x4 1119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 1129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 1139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_idct_2x2 1149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 1159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 1169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectEXTERN(void) jpeg_idct_1x1 1179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 1189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 1199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 1229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Macros for handling fixed-point arithmetic; these are used by many 1239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * but not all of the DCT/IDCT modules. 1249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 1259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * All values are expected to be of type INT32. 1269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Fractional constants are scaled left by CONST_BITS bits. 1279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * CONST_BITS is defined within each module using these macros, 1289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * and may differ from one module to the next. 1299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define ONE ((INT32) 1) 1329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define CONST_SCALE (ONE << CONST_BITS) 1339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Convert a positive real constant to an integer scaled by CONST_SCALE. 1359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Caution: some C compilers fail to reduce "FIX(constant)" at compile time, 1369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * thus causing a lot of useless floating-point operations at run time. 1379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5)) 1409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Descale and correctly round an INT32 value that's scaled by N bits. 1429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * We assume RIGHT_SHIFT rounds towards minus infinity, so adding 1439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * the fudge factor is correct for either sign of X. 1449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n) 1479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. 1499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This macro is used only when the two inputs will actually be no more than 1509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a 1519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * full 32x32 multiply. This provides a useful speedup on many machines. 1529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Unfortunately there is no way to specify a 16x16->32 multiply portably 1539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * in C, but some C compilers will do the right thing if you provide the 1549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * correct combination of casts. 1559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ 1589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const))) 1599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 1609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */ 1619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const))) 1629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 1639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifndef MULTIPLY16C16 /* default definition */ 1659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MULTIPLY16C16(var,const) ((var) * (const)) 1669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 1679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Same except both inputs are variables. */ 1699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ 1719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2))) 1729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 1739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifndef MULTIPLY16V16 /* default definition */ 1759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MULTIPLY16V16(var1,var2) ((var1) * (var2)) 1769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 177