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comparison: media/libjpeg/jdct.h
media/libjpeg/jdct.h
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| 1 /* | |
| 2 * jdct.h | |
| 3 * | |
| 4 * Copyright (C) 1994-1996, Thomas G. Lane. | |
| 5 * This file is part of the Independent JPEG Group's software. | |
| 6 * For conditions of distribution and use, see the accompanying README file. | |
| 7 * | |
| 8 * This include file contains common declarations for the forward and | |
| 9 * inverse DCT modules. These declarations are private to the DCT managers | |
| 10 * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms. | |
| 11 * The individual DCT algorithms are kept in separate files to ease | |
| 12 * machine-dependent tuning (e.g., assembly coding). | |
| 13 */ | |
| 14 | |
| 15 | |
| 16 /* | |
| 17 * A forward DCT routine is given a pointer to a work area of type DCTELEM[]; | |
| 18 * the DCT is to be performed in-place in that buffer. Type DCTELEM is int | |
| 19 * for 8-bit samples, INT32 for 12-bit samples. (NOTE: Floating-point DCT | |
| 20 * implementations use an array of type FAST_FLOAT, instead.) | |
| 21 * The DCT inputs are expected to be signed (range +-CENTERJSAMPLE). | |
| 22 * The DCT outputs are returned scaled up by a factor of 8; they therefore | |
| 23 * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This | |
| 24 * convention improves accuracy in integer implementations and saves some | |
| 25 * work in floating-point ones. | |
| 26 * Quantization of the output coefficients is done by jcdctmgr.c. This | |
| 27 * step requires an unsigned type and also one with twice the bits. | |
| 28 */ | |
| 29 | |
| 30 #if BITS_IN_JSAMPLE == 8 | |
| 31 #ifndef WITH_SIMD | |
| 32 typedef int DCTELEM; /* 16 or 32 bits is fine */ | |
| 33 typedef unsigned int UDCTELEM; | |
| 34 typedef unsigned long long UDCTELEM2; | |
| 35 #else | |
| 36 typedef short DCTELEM; /* prefer 16 bit with SIMD for parellelism */ | |
| 37 typedef unsigned short UDCTELEM; | |
| 38 typedef unsigned int UDCTELEM2; | |
| 39 #endif | |
| 40 #else | |
| 41 typedef INT32 DCTELEM; /* must have 32 bits */ | |
| 42 typedef UINT32 UDCTELEM; | |
| 43 typedef unsigned long long UDCTELEM2; | |
| 44 #endif | |
| 45 | |
| 46 | |
| 47 /* | |
| 48 * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer | |
| 49 * to an output sample array. The routine must dequantize the input data as | |
| 50 * well as perform the IDCT; for dequantization, it uses the multiplier table | |
| 51 * pointed to by compptr->dct_table. The output data is to be placed into the | |
| 52 * sample array starting at a specified column. (Any row offset needed will | |
| 53 * be applied to the array pointer before it is passed to the IDCT code.) | |
| 54 * Note that the number of samples emitted by the IDCT routine is | |
| 55 * DCT_scaled_size * DCT_scaled_size. | |
| 56 */ | |
| 57 | |
| 58 /* typedef inverse_DCT_method_ptr is declared in jpegint.h */ | |
| 59 | |
| 60 /* | |
| 61 * Each IDCT routine has its own ideas about the best dct_table element type. | |
| 62 */ | |
| 63 | |
| 64 typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */ | |
| 65 #if BITS_IN_JSAMPLE == 8 | |
| 66 typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */ | |
| 67 #define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */ | |
| 68 #else | |
| 69 typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */ | |
| 70 #define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */ | |
| 71 #endif | |
| 72 typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */ | |
| 73 | |
| 74 | |
| 75 /* | |
| 76 * Each IDCT routine is responsible for range-limiting its results and | |
| 77 * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could | |
| 78 * be quite far out of range if the input data is corrupt, so a bulletproof | |
| 79 * range-limiting step is required. We use a mask-and-table-lookup method | |
| 80 * to do the combined operations quickly. See the comments with | |
| 81 * prepare_range_limit_table (in jdmaster.c) for more info. | |
| 82 */ | |
| 83 | |
| 84 #define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE) | |
| 85 | |
| 86 #define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */ | |
| 87 | |
| 88 | |
| 89 /* Short forms of external names for systems with brain-damaged linkers. */ | |
| 90 | |
| 91 #ifdef NEED_SHORT_EXTERNAL_NAMES | |
| 92 #define jpeg_fdct_islow jFDislow | |
| 93 #define jpeg_fdct_ifast jFDifast | |
| 94 #define jpeg_fdct_float jFDfloat | |
| 95 #define jpeg_idct_islow jRDislow | |
| 96 #define jpeg_idct_ifast jRDifast | |
| 97 #define jpeg_idct_float jRDfloat | |
| 98 #define jpeg_idct_7x7 jRD7x7 | |
| 99 #define jpeg_idct_6x6 jRD6x6 | |
| 100 #define jpeg_idct_5x5 jRD5x5 | |
| 101 #define jpeg_idct_4x4 jRD4x4 | |
| 102 #define jpeg_idct_3x3 jRD3x3 | |
| 103 #define jpeg_idct_2x2 jRD2x2 | |
| 104 #define jpeg_idct_1x1 jRD1x1 | |
| 105 #define jpeg_idct_9x9 jRD9x9 | |
| 106 #define jpeg_idct_10x10 jRD10x10 | |
| 107 #define jpeg_idct_11x11 jRD11x11 | |
| 108 #define jpeg_idct_12x12 jRD12x12 | |
| 109 #define jpeg_idct_13x13 jRD13x13 | |
| 110 #define jpeg_idct_14x14 jRD14x14 | |
| 111 #define jpeg_idct_15x15 jRD15x15 | |
| 112 #define jpeg_idct_16x16 jRD16x16 | |
| 113 #endif /* NEED_SHORT_EXTERNAL_NAMES */ | |
| 114 | |
| 115 /* Extern declarations for the forward and inverse DCT routines. */ | |
| 116 | |
| 117 EXTERN(void) jpeg_fdct_islow JPP((DCTELEM * data)); | |
| 118 EXTERN(void) jpeg_fdct_ifast JPP((DCTELEM * data)); | |
| 119 EXTERN(void) jpeg_fdct_float JPP((FAST_FLOAT * data)); | |
| 120 | |
| 121 EXTERN(void) jpeg_idct_islow | |
| 122 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 123 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 124 EXTERN(void) jpeg_idct_ifast | |
| 125 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 126 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 127 EXTERN(void) jpeg_idct_float | |
| 128 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 129 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 130 EXTERN(void) jpeg_idct_7x7 | |
| 131 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 132 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 133 EXTERN(void) jpeg_idct_6x6 | |
| 134 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 135 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 136 EXTERN(void) jpeg_idct_5x5 | |
| 137 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 138 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 139 EXTERN(void) jpeg_idct_4x4 | |
| 140 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 141 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 142 EXTERN(void) jpeg_idct_3x3 | |
| 143 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 144 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 145 EXTERN(void) jpeg_idct_2x2 | |
| 146 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 147 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 148 EXTERN(void) jpeg_idct_1x1 | |
| 149 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 150 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 151 EXTERN(void) jpeg_idct_9x9 | |
| 152 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 153 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 154 EXTERN(void) jpeg_idct_10x10 | |
| 155 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 156 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 157 EXTERN(void) jpeg_idct_11x11 | |
| 158 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 159 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 160 EXTERN(void) jpeg_idct_12x12 | |
| 161 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 162 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 163 EXTERN(void) jpeg_idct_13x13 | |
| 164 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 165 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 166 EXTERN(void) jpeg_idct_14x14 | |
| 167 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 168 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 169 EXTERN(void) jpeg_idct_15x15 | |
| 170 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 171 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 172 EXTERN(void) jpeg_idct_16x16 | |
| 173 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, | |
| 174 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); | |
| 175 | |
| 176 | |
| 177 /* | |
| 178 * Macros for handling fixed-point arithmetic; these are used by many | |
| 179 * but not all of the DCT/IDCT modules. | |
| 180 * | |
| 181 * All values are expected to be of type INT32. | |
| 182 * Fractional constants are scaled left by CONST_BITS bits. | |
| 183 * CONST_BITS is defined within each module using these macros, | |
| 184 * and may differ from one module to the next. | |
| 185 */ | |
| 186 | |
| 187 #define ONE ((INT32) 1) | |
| 188 #define CONST_SCALE (ONE << CONST_BITS) | |
| 189 | |
| 190 /* Convert a positive real constant to an integer scaled by CONST_SCALE. | |
| 191 * Caution: some C compilers fail to reduce "FIX(constant)" at compile time, | |
| 192 * thus causing a lot of useless floating-point operations at run time. | |
| 193 */ | |
| 194 | |
| 195 #define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5)) | |
| 196 | |
| 197 /* Descale and correctly round an INT32 value that's scaled by N bits. | |
| 198 * We assume RIGHT_SHIFT rounds towards minus infinity, so adding | |
| 199 * the fudge factor is correct for either sign of X. | |
| 200 */ | |
| 201 | |
| 202 #define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n) | |
| 203 | |
| 204 /* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. | |
| 205 * This macro is used only when the two inputs will actually be no more than | |
| 206 * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a | |
| 207 * full 32x32 multiply. This provides a useful speedup on many machines. | |
| 208 * Unfortunately there is no way to specify a 16x16->32 multiply portably | |
| 209 * in C, but some C compilers will do the right thing if you provide the | |
| 210 * correct combination of casts. | |
| 211 */ | |
| 212 | |
| 213 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ | |
| 214 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const))) | |
| 215 #endif | |
| 216 #ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */ | |
| 217 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const))) | |
| 218 #endif | |
| 219 | |
| 220 #ifndef MULTIPLY16C16 /* default definition */ | |
| 221 #define MULTIPLY16C16(var,const) ((var) * (const)) | |
| 222 #endif | |
| 223 | |
| 224 /* Same except both inputs are variables. */ | |
| 225 | |
| 226 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ | |
| 227 #define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2))) | |
| 228 #endif | |
| 229 | |
| 230 #ifndef MULTIPLY16V16 /* default definition */ | |
| 231 #define MULTIPLY16V16(var1,var2) ((var1) * (var2)) | |
| 232 #endif |
