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 an input sample array and 18 * a pointer to a work area of type DCTELEM[]; the DCT is to be performed 19 * in-place in that buffer. Type DCTELEM is int for 8-bit samples, INT32 20 * for 12-bit samples. (NOTE: Floating-point DCT implementations use an 21 * array of type FAST_FLOAT, instead.) 22 * The input data is to be fetched from the sample array starting at a 23 * specified column. (Any row offset needed will be applied to the array 24 * pointer before it is passed to the FDCT code.) 25 * Note that the number of samples fetched by the FDCT routine is 26 * DCT_h_scaled_size * DCT_v_scaled_size. 27 * The DCT outputs are returned scaled up by a factor of 8; they therefore 28 * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This 29 * convention improves accuracy in integer implementations and saves some 30 * work in floating-point ones. 31 * Quantization of the output coefficients is done by jcdctmgr.c. 32 */ 33 34 #if BITS_IN_JSAMPLE == 8 35 typedef int DCTELEM; /* 16 or 32 bits is fine */ 36 #else 37 typedef INT32 DCTELEM; /* must have 32 bits */ 38 #endif 39 40 typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data, 41 JSAMPARRAY sample_data, 42 JDIMENSION start_col)); 43 typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data, 44 JSAMPARRAY sample_data, 45 JDIMENSION start_col)); 46 47 48 /* 49 * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer 50 * to an output sample array. The routine must dequantize the input data as 51 * well as perform the IDCT; for dequantization, it uses the multiplier table 52 * pointed to by compptr->dct_table. The output data is to be placed into the 53 * sample array starting at a specified column. (Any row offset needed will 54 * be applied to the array pointer before it is passed to the IDCT code.) 55 * Note that the number of samples emitted by the IDCT routine is 56 * DCT_h_scaled_size * DCT_v_scaled_size. 57 */ 58 59 /* typedef inverse_DCT_method_ptr is declared in jpegint.h */ 60 61 /* 62 * Each IDCT routine has its own ideas about the best dct_table element type. 63 */ 64 65 typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */ 66 #if BITS_IN_JSAMPLE == 8 67 typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */ 68 #define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */ 69 #else 70 typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */ 71 #define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */ 72 #endif 73 typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */ 74 75 76 /* 77 * Each IDCT routine is responsible for range-limiting its results and 78 * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could 79 * be quite far out of range if the input data is corrupt, so a bulletproof 80 * range-limiting step is required. We use a mask-and-table-lookup method 81 * to do the combined operations quickly. See the comments with 82 * prepare_range_limit_table (in jdmaster.c) for more info. 83 */ 84 85 #define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE) 86 87 #define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */ 88 89 90 /* Short forms of external names for systems with brain-damaged linkers. */ 91 92 #ifdef NEED_SHORT_EXTERNAL_NAMES 93 #define jpeg_fdct_islow jFDislow 94 #define jpeg_fdct_ifast jFDifast 95 #define jpeg_fdct_float jFDfloat 96 #define jpeg_fdct_7x7 jFD7x7 97 #define jpeg_fdct_6x6 jFD6x6 98 #define jpeg_fdct_5x5 jFD5x5 99 #define jpeg_fdct_4x4 jFD4x4 100 #define jpeg_fdct_3x3 jFD3x3 101 #define jpeg_fdct_2x2 jFD2x2 102 #define jpeg_fdct_1x1 jFD1x1 103 #define jpeg_fdct_9x9 jFD9x9 104 #define jpeg_fdct_10x10 jFD10x10 105 #define jpeg_fdct_11x11 jFD11x11 106 #define jpeg_fdct_12x12 jFD12x12 107 #define jpeg_fdct_13x13 jFD13x13 108 #define jpeg_fdct_14x14 jFD14x14 109 #define jpeg_fdct_15x15 jFD15x15 110 #define jpeg_fdct_16x16 jFD16x16 111 #define jpeg_fdct_16x8 jFD16x8 112 #define jpeg_fdct_14x7 jFD14x7 113 #define jpeg_fdct_12x6 jFD12x6 114 #define jpeg_fdct_10x5 jFD10x5 115 #define jpeg_fdct_8x4 jFD8x4 116 #define jpeg_fdct_6x3 jFD6x3 117 #define jpeg_fdct_4x2 jFD4x2 118 #define jpeg_fdct_2x1 jFD2x1 119 #define jpeg_fdct_8x16 jFD8x16 120 #define jpeg_fdct_7x14 jFD7x14 121 #define jpeg_fdct_6x12 jFD6x12 122 #define jpeg_fdct_5x10 jFD5x10 123 #define jpeg_fdct_4x8 jFD4x8 124 #define jpeg_fdct_3x6 jFD3x6 125 #define jpeg_fdct_2x4 jFD2x4 126 #define jpeg_fdct_1x2 jFD1x2 127 #define jpeg_idct_islow jRDislow 128 #define jpeg_idct_ifast jRDifast 129 #define jpeg_idct_float jRDfloat 130 #define jpeg_idct_7x7 jRD7x7 131 #define jpeg_idct_6x6 jRD6x6 132 #define jpeg_idct_5x5 jRD5x5 133 #define jpeg_idct_4x4 jRD4x4 134 #define jpeg_idct_3x3 jRD3x3 135 #define jpeg_idct_2x2 jRD2x2 136 #define jpeg_idct_1x1 jRD1x1 137 #define jpeg_idct_9x9 jRD9x9 138 #define jpeg_idct_10x10 jRD10x10 139 #define jpeg_idct_11x11 jRD11x11 140 #define jpeg_idct_12x12 jRD12x12 141 #define jpeg_idct_13x13 jRD13x13 142 #define jpeg_idct_14x14 jRD14x14 143 #define jpeg_idct_15x15 jRD15x15 144 #define jpeg_idct_16x16 jRD16x16 145 #define jpeg_idct_16x8 jRD16x8 146 #define jpeg_idct_14x7 jRD14x7 147 #define jpeg_idct_12x6 jRD12x6 148 #define jpeg_idct_10x5 jRD10x5 149 #define jpeg_idct_8x4 jRD8x4 150 #define jpeg_idct_6x3 jRD6x3 151 #define jpeg_idct_4x2 jRD4x2 152 #define jpeg_idct_2x1 jRD2x1 153 #define jpeg_idct_8x16 jRD8x16 154 #define jpeg_idct_7x14 jRD7x14 155 #define jpeg_idct_6x12 jRD6x12 156 #define jpeg_idct_5x10 jRD5x10 157 #define jpeg_idct_4x8 jRD4x8 158 #define jpeg_idct_3x6 jRD3x8 159 #define jpeg_idct_2x4 jRD2x4 160 #define jpeg_idct_1x2 jRD1x2 161 #endif /* NEED_SHORT_EXTERNAL_NAMES */ 162 163 /* Extern declarations for the forward and inverse DCT routines. */ 164 165 EXTERN(void) jpeg_fdct_islow 166 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 167 EXTERN(void) jpeg_fdct_ifast 168 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 169 EXTERN(void) jpeg_fdct_float 170 JPP((FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 171 EXTERN(void) jpeg_fdct_7x7 172 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 173 EXTERN(void) jpeg_fdct_6x6 174 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 175 EXTERN(void) jpeg_fdct_5x5 176 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 177 EXTERN(void) jpeg_fdct_4x4 178 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 179 EXTERN(void) jpeg_fdct_3x3 180 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 181 EXTERN(void) jpeg_fdct_2x2 182 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 183 EXTERN(void) jpeg_fdct_1x1 184 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 185 EXTERN(void) jpeg_fdct_9x9 186 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 187 EXTERN(void) jpeg_fdct_10x10 188 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 189 EXTERN(void) jpeg_fdct_11x11 190 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 191 EXTERN(void) jpeg_fdct_12x12 192 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 193 EXTERN(void) jpeg_fdct_13x13 194 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 195 EXTERN(void) jpeg_fdct_14x14 196 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 197 EXTERN(void) jpeg_fdct_15x15 198 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 199 EXTERN(void) jpeg_fdct_16x16 200 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 201 EXTERN(void) jpeg_fdct_16x8 202 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 203 EXTERN(void) jpeg_fdct_14x7 204 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 205 EXTERN(void) jpeg_fdct_12x6 206 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 207 EXTERN(void) jpeg_fdct_10x5 208 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 209 EXTERN(void) jpeg_fdct_8x4 210 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 211 EXTERN(void) jpeg_fdct_6x3 212 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 213 EXTERN(void) jpeg_fdct_4x2 214 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 215 EXTERN(void) jpeg_fdct_2x1 216 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 217 EXTERN(void) jpeg_fdct_8x16 218 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 219 EXTERN(void) jpeg_fdct_7x14 220 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 221 EXTERN(void) jpeg_fdct_6x12 222 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 223 EXTERN(void) jpeg_fdct_5x10 224 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 225 EXTERN(void) jpeg_fdct_4x8 226 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 227 EXTERN(void) jpeg_fdct_3x6 228 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 229 EXTERN(void) jpeg_fdct_2x4 230 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 231 EXTERN(void) jpeg_fdct_1x2 232 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)); 233 234 EXTERN(void) jpeg_idct_islow 235 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 236 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 237 EXTERN(void) jpeg_idct_ifast 238 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 239 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 240 EXTERN(void) jpeg_idct_float 241 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 242 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 243 EXTERN(void) jpeg_idct_7x7 244 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 245 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 246 EXTERN(void) jpeg_idct_6x6 247 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 248 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 249 EXTERN(void) jpeg_idct_5x5 250 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 251 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 252 EXTERN(void) jpeg_idct_4x4 253 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 254 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 255 EXTERN(void) jpeg_idct_3x3 256 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 257 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 258 EXTERN(void) jpeg_idct_2x2 259 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 260 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 261 EXTERN(void) jpeg_idct_1x1 262 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 263 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 264 EXTERN(void) jpeg_idct_9x9 265 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 266 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 267 EXTERN(void) jpeg_idct_10x10 268 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 269 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 270 EXTERN(void) jpeg_idct_11x11 271 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 272 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 273 EXTERN(void) jpeg_idct_12x12 274 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 275 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 276 EXTERN(void) jpeg_idct_13x13 277 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 278 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 279 EXTERN(void) jpeg_idct_14x14 280 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 281 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 282 EXTERN(void) jpeg_idct_15x15 283 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 284 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 285 EXTERN(void) jpeg_idct_16x16 286 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 287 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 288 EXTERN(void) jpeg_idct_16x8 289 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 290 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 291 EXTERN(void) jpeg_idct_14x7 292 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 293 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 294 EXTERN(void) jpeg_idct_12x6 295 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 296 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 297 EXTERN(void) jpeg_idct_10x5 298 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 299 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 300 EXTERN(void) jpeg_idct_8x4 301 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 302 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 303 EXTERN(void) jpeg_idct_6x3 304 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 305 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 306 EXTERN(void) jpeg_idct_4x2 307 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 308 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 309 EXTERN(void) jpeg_idct_2x1 310 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 311 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 312 EXTERN(void) jpeg_idct_8x16 313 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 314 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 315 EXTERN(void) jpeg_idct_7x14 316 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 317 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 318 EXTERN(void) jpeg_idct_6x12 319 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 320 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 321 EXTERN(void) jpeg_idct_5x10 322 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 323 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 324 EXTERN(void) jpeg_idct_4x8 325 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 326 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 327 EXTERN(void) jpeg_idct_3x6 328 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 329 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 330 EXTERN(void) jpeg_idct_2x4 331 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 332 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 333 EXTERN(void) jpeg_idct_1x2 334 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, 335 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); 336 337 338 /* 339 * Macros for handling fixed-point arithmetic; these are used by many 340 * but not all of the DCT/IDCT modules. 341 * 342 * All values are expected to be of type INT32. 343 * Fractional constants are scaled left by CONST_BITS bits. 344 * CONST_BITS is defined within each module using these macros, 345 * and may differ from one module to the next. 346 */ 347 348 #define ONE ((INT32) 1) 349 #define CONST_SCALE (ONE << CONST_BITS) 350 351 /* Convert a positive real constant to an integer scaled by CONST_SCALE. 352 * Caution: some C compilers fail to reduce "FIX(constant)" at compile time, 353 * thus causing a lot of useless floating-point operations at run time. 354 */ 355 356 #define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5)) 357 358 /* Descale and correctly round an INT32 value that's scaled by N bits. 359 * We assume RIGHT_SHIFT rounds towards minus infinity, so adding 360 * the fudge factor is correct for either sign of X. 361 */ 362 363 #define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n) 364 365 /* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. 366 * This macro is used only when the two inputs will actually be no more than 367 * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a 368 * full 32x32 multiply. This provides a useful speedup on many machines. 369 * Unfortunately there is no way to specify a 16x16->32 multiply portably 370 * in C, but some C compilers will do the right thing if you provide the 371 * correct combination of casts. 372 */ 373 374 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ 375 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const))) 376 #endif 377 #ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */ 378 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const))) 379 #endif 380 381 #ifndef MULTIPLY16C16 /* default definition */ 382 #define MULTIPLY16C16(var,const) ((var) * (const)) 383 #endif 384 385 /* Same except both inputs are variables. */ 386 387 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ 388 #define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2))) 389 #endif 390 391 #ifndef MULTIPLY16V16 /* default definition */ 392 #define MULTIPLY16V16(var1,var2) ((var1) * (var2)) 393 #endif 394
