1 /* 2 * jcdctmgr.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1994-1996, Thomas G. Lane. 6 * libjpeg-turbo Modifications: 7 * Copyright (C) 1999-2006, MIYASAKA Masaru. 8 * Copyright 2009 Pierre Ossman <ossman (at) cendio.se> for Cendio AB 9 * Copyright (C) 2011, 2014-2015, D. R. Commander. 10 * For conditions of distribution and use, see the accompanying README.ijg 11 * file. 12 * 13 * This file contains the forward-DCT management logic. 14 * This code selects a particular DCT implementation to be used, 15 * and it performs related housekeeping chores including coefficient 16 * quantization. 17 */ 18 19 #define JPEG_INTERNALS 20 #include "jinclude.h" 21 #include "jpeglib.h" 22 #include "jdct.h" /* Private declarations for DCT subsystem */ 23 #include "jsimddct.h" 24 25 26 /* Private subobject for this module */ 27 28 typedef void (*forward_DCT_method_ptr) (DCTELEM *data); 29 typedef void (*float_DCT_method_ptr) (FAST_FLOAT *data); 30 31 typedef void (*convsamp_method_ptr) (JSAMPARRAY sample_data, 32 JDIMENSION start_col, 33 DCTELEM *workspace); 34 typedef void (*float_convsamp_method_ptr) (JSAMPARRAY sample_data, 35 JDIMENSION start_col, 36 FAST_FLOAT *workspace); 37 38 typedef void (*quantize_method_ptr) (JCOEFPTR coef_block, DCTELEM *divisors, 39 DCTELEM *workspace); 40 typedef void (*float_quantize_method_ptr) (JCOEFPTR coef_block, 41 FAST_FLOAT *divisors, 42 FAST_FLOAT *workspace); 43 44 METHODDEF(void) quantize (JCOEFPTR, DCTELEM *, DCTELEM *); 45 46 typedef struct { 47 struct jpeg_forward_dct pub; /* public fields */ 48 49 /* Pointer to the DCT routine actually in use */ 50 forward_DCT_method_ptr dct; 51 convsamp_method_ptr convsamp; 52 quantize_method_ptr quantize; 53 54 /* The actual post-DCT divisors --- not identical to the quant table 55 * entries, because of scaling (especially for an unnormalized DCT). 56 * Each table is given in normal array order. 57 */ 58 DCTELEM *divisors[NUM_QUANT_TBLS]; 59 60 /* work area for FDCT subroutine */ 61 DCTELEM *workspace; 62 63 #ifdef DCT_FLOAT_SUPPORTED 64 /* Same as above for the floating-point case. */ 65 float_DCT_method_ptr float_dct; 66 float_convsamp_method_ptr float_convsamp; 67 float_quantize_method_ptr float_quantize; 68 FAST_FLOAT *float_divisors[NUM_QUANT_TBLS]; 69 FAST_FLOAT *float_workspace; 70 #endif 71 } my_fdct_controller; 72 73 typedef my_fdct_controller *my_fdct_ptr; 74 75 76 #if BITS_IN_JSAMPLE == 8 77 78 /* 79 * Find the highest bit in an integer through binary search. 80 */ 81 82 LOCAL(int) 83 flss (UINT16 val) 84 { 85 int bit; 86 87 bit = 16; 88 89 if (!val) 90 return 0; 91 92 if (!(val & 0xff00)) { 93 bit -= 8; 94 val <<= 8; 95 } 96 if (!(val & 0xf000)) { 97 bit -= 4; 98 val <<= 4; 99 } 100 if (!(val & 0xc000)) { 101 bit -= 2; 102 val <<= 2; 103 } 104 if (!(val & 0x8000)) { 105 bit -= 1; 106 val <<= 1; 107 } 108 109 return bit; 110 } 111 112 113 /* 114 * Compute values to do a division using reciprocal. 115 * 116 * This implementation is based on an algorithm described in 117 * "How to optimize for the Pentium family of microprocessors" 118 * (http://www.agner.org/assem/). 119 * More information about the basic algorithm can be found in 120 * the paper "Integer Division Using Reciprocals" by Robert Alverson. 121 * 122 * The basic idea is to replace x/d by x * d^-1. In order to store 123 * d^-1 with enough precision we shift it left a few places. It turns 124 * out that this algoright gives just enough precision, and also fits 125 * into DCTELEM: 126 * 127 * b = (the number of significant bits in divisor) - 1 128 * r = (word size) + b 129 * f = 2^r / divisor 130 * 131 * f will not be an integer for most cases, so we need to compensate 132 * for the rounding error introduced: 133 * 134 * no fractional part: 135 * 136 * result = input >> r 137 * 138 * fractional part of f < 0.5: 139 * 140 * round f down to nearest integer 141 * result = ((input + 1) * f) >> r 142 * 143 * fractional part of f > 0.5: 144 * 145 * round f up to nearest integer 146 * result = (input * f) >> r 147 * 148 * This is the original algorithm that gives truncated results. But we 149 * want properly rounded results, so we replace "input" with 150 * "input + divisor/2". 151 * 152 * In order to allow SIMD implementations we also tweak the values to 153 * allow the same calculation to be made at all times: 154 * 155 * dctbl[0] = f rounded to nearest integer 156 * dctbl[1] = divisor / 2 (+ 1 if fractional part of f < 0.5) 157 * dctbl[2] = 1 << ((word size) * 2 - r) 158 * dctbl[3] = r - (word size) 159 * 160 * dctbl[2] is for stupid instruction sets where the shift operation 161 * isn't member wise (e.g. MMX). 162 * 163 * The reason dctbl[2] and dctbl[3] reduce the shift with (word size) 164 * is that most SIMD implementations have a "multiply and store top 165 * half" operation. 166 * 167 * Lastly, we store each of the values in their own table instead 168 * of in a consecutive manner, yet again in order to allow SIMD 169 * routines. 170 */ 171 172 LOCAL(int) 173 compute_reciprocal (UINT16 divisor, DCTELEM *dtbl) 174 { 175 UDCTELEM2 fq, fr; 176 UDCTELEM c; 177 int b, r; 178 179 if (divisor == 1) { 180 /* divisor == 1 means unquantized, so these reciprocal/correction/shift 181 * values will cause the C quantization algorithm to act like the 182 * identity function. Since only the C quantization algorithm is used in 183 * these cases, the scale value is irrelevant. 184 */ 185 dtbl[DCTSIZE2 * 0] = (DCTELEM) 1; /* reciprocal */ 186 dtbl[DCTSIZE2 * 1] = (DCTELEM) 0; /* correction */ 187 dtbl[DCTSIZE2 * 2] = (DCTELEM) 1; /* scale */ 188 dtbl[DCTSIZE2 * 3] = -(DCTELEM) (sizeof(DCTELEM) * 8); /* shift */ 189 return 0; 190 } 191 192 b = flss(divisor) - 1; 193 r = sizeof(DCTELEM) * 8 + b; 194 195 fq = ((UDCTELEM2)1 << r) / divisor; 196 fr = ((UDCTELEM2)1 << r) % divisor; 197 198 c = divisor / 2; /* for rounding */ 199 200 if (fr == 0) { /* divisor is power of two */ 201 /* fq will be one bit too large to fit in DCTELEM, so adjust */ 202 fq >>= 1; 203 r--; 204 } else if (fr <= (divisor / 2U)) { /* fractional part is < 0.5 */ 205 c++; 206 } else { /* fractional part is > 0.5 */ 207 fq++; 208 } 209 210 dtbl[DCTSIZE2 * 0] = (DCTELEM) fq; /* reciprocal */ 211 dtbl[DCTSIZE2 * 1] = (DCTELEM) c; /* correction + roundfactor */ 212 #ifdef WITH_SIMD 213 dtbl[DCTSIZE2 * 2] = (DCTELEM) (1 << (sizeof(DCTELEM)*8*2 - r)); /* scale */ 214 #else 215 dtbl[DCTSIZE2 * 2] = 1; 216 #endif 217 dtbl[DCTSIZE2 * 3] = (DCTELEM) r - sizeof(DCTELEM)*8; /* shift */ 218 219 if(r <= 16) return 0; 220 else return 1; 221 } 222 223 #endif 224 225 226 /* 227 * Initialize for a processing pass. 228 * Verify that all referenced Q-tables are present, and set up 229 * the divisor table for each one. 230 * In the current implementation, DCT of all components is done during 231 * the first pass, even if only some components will be output in the 232 * first scan. Hence all components should be examined here. 233 */ 234 235 METHODDEF(void) 236 start_pass_fdctmgr (j_compress_ptr cinfo) 237 { 238 my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; 239 int ci, qtblno, i; 240 jpeg_component_info *compptr; 241 JQUANT_TBL *qtbl; 242 DCTELEM *dtbl; 243 244 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 245 ci++, compptr++) { 246 qtblno = compptr->quant_tbl_no; 247 /* Make sure specified quantization table is present */ 248 if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || 249 cinfo->quant_tbl_ptrs[qtblno] == NULL) 250 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); 251 qtbl = cinfo->quant_tbl_ptrs[qtblno]; 252 /* Compute divisors for this quant table */ 253 /* We may do this more than once for same table, but it's not a big deal */ 254 switch (cinfo->dct_method) { 255 #ifdef DCT_ISLOW_SUPPORTED 256 case JDCT_ISLOW: 257 /* For LL&M IDCT method, divisors are equal to raw quantization 258 * coefficients multiplied by 8 (to counteract scaling). 259 */ 260 if (fdct->divisors[qtblno] == NULL) { 261 fdct->divisors[qtblno] = (DCTELEM *) 262 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 263 (DCTSIZE2 * 4) * sizeof(DCTELEM)); 264 } 265 dtbl = fdct->divisors[qtblno]; 266 for (i = 0; i < DCTSIZE2; i++) { 267 #if BITS_IN_JSAMPLE == 8 268 if (!compute_reciprocal(qtbl->quantval[i] << 3, &dtbl[i]) && 269 fdct->quantize == jsimd_quantize) 270 fdct->quantize = quantize; 271 #else 272 dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3; 273 #endif 274 } 275 break; 276 #endif 277 #ifdef DCT_IFAST_SUPPORTED 278 case JDCT_IFAST: 279 { 280 /* For AA&N IDCT method, divisors are equal to quantization 281 * coefficients scaled by scalefactor[row]*scalefactor[col], where 282 * scalefactor[0] = 1 283 * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7 284 * We apply a further scale factor of 8. 285 */ 286 #define CONST_BITS 14 287 static const INT16 aanscales[DCTSIZE2] = { 288 /* precomputed values scaled up by 14 bits */ 289 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520, 290 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270, 291 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906, 292 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315, 293 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520, 294 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552, 295 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446, 296 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247 297 }; 298 SHIFT_TEMPS 299 300 if (fdct->divisors[qtblno] == NULL) { 301 fdct->divisors[qtblno] = (DCTELEM *) 302 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 303 (DCTSIZE2 * 4) * sizeof(DCTELEM)); 304 } 305 dtbl = fdct->divisors[qtblno]; 306 for (i = 0; i < DCTSIZE2; i++) { 307 #if BITS_IN_JSAMPLE == 8 308 if (!compute_reciprocal( 309 DESCALE(MULTIPLY16V16((JLONG) qtbl->quantval[i], 310 (JLONG) aanscales[i]), 311 CONST_BITS-3), &dtbl[i]) && 312 fdct->quantize == jsimd_quantize) 313 fdct->quantize = quantize; 314 #else 315 dtbl[i] = (DCTELEM) 316 DESCALE(MULTIPLY16V16((JLONG) qtbl->quantval[i], 317 (JLONG) aanscales[i]), 318 CONST_BITS-3); 319 #endif 320 } 321 } 322 break; 323 #endif 324 #ifdef DCT_FLOAT_SUPPORTED 325 case JDCT_FLOAT: 326 { 327 /* For float AA&N IDCT method, divisors are equal to quantization 328 * coefficients scaled by scalefactor[row]*scalefactor[col], where 329 * scalefactor[0] = 1 330 * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7 331 * We apply a further scale factor of 8. 332 * What's actually stored is 1/divisor so that the inner loop can 333 * use a multiplication rather than a division. 334 */ 335 FAST_FLOAT *fdtbl; 336 int row, col; 337 static const double aanscalefactor[DCTSIZE] = { 338 1.0, 1.387039845, 1.306562965, 1.175875602, 339 1.0, 0.785694958, 0.541196100, 0.275899379 340 }; 341 342 if (fdct->float_divisors[qtblno] == NULL) { 343 fdct->float_divisors[qtblno] = (FAST_FLOAT *) 344 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 345 DCTSIZE2 * sizeof(FAST_FLOAT)); 346 } 347 fdtbl = fdct->float_divisors[qtblno]; 348 i = 0; 349 for (row = 0; row < DCTSIZE; row++) { 350 for (col = 0; col < DCTSIZE; col++) { 351 fdtbl[i] = (FAST_FLOAT) 352 (1.0 / (((double) qtbl->quantval[i] * 353 aanscalefactor[row] * aanscalefactor[col] * 8.0))); 354 i++; 355 } 356 } 357 } 358 break; 359 #endif 360 default: 361 ERREXIT(cinfo, JERR_NOT_COMPILED); 362 break; 363 } 364 } 365 } 366 367 368 /* 369 * Load data into workspace, applying unsigned->signed conversion. 370 */ 371 372 METHODDEF(void) 373 convsamp (JSAMPARRAY sample_data, JDIMENSION start_col, DCTELEM *workspace) 374 { 375 register DCTELEM *workspaceptr; 376 register JSAMPROW elemptr; 377 register int elemr; 378 379 workspaceptr = workspace; 380 for (elemr = 0; elemr < DCTSIZE; elemr++) { 381 elemptr = sample_data[elemr] + start_col; 382 383 #if DCTSIZE == 8 /* unroll the inner loop */ 384 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 385 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 386 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 387 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 388 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 389 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 390 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 391 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 392 #else 393 { 394 register int elemc; 395 for (elemc = DCTSIZE; elemc > 0; elemc--) 396 *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; 397 } 398 #endif 399 } 400 } 401 402 403 /* 404 * Quantize/descale the coefficients, and store into coef_blocks[]. 405 */ 406 407 METHODDEF(void) 408 quantize (JCOEFPTR coef_block, DCTELEM *divisors, DCTELEM *workspace) 409 { 410 int i; 411 DCTELEM temp; 412 JCOEFPTR output_ptr = coef_block; 413 414 #if BITS_IN_JSAMPLE == 8 415 416 UDCTELEM recip, corr; 417 int shift; 418 UDCTELEM2 product; 419 420 for (i = 0; i < DCTSIZE2; i++) { 421 temp = workspace[i]; 422 recip = divisors[i + DCTSIZE2 * 0]; 423 corr = divisors[i + DCTSIZE2 * 1]; 424 shift = divisors[i + DCTSIZE2 * 3]; 425 426 if (temp < 0) { 427 temp = -temp; 428 product = (UDCTELEM2)(temp + corr) * recip; 429 product >>= shift + sizeof(DCTELEM)*8; 430 temp = (DCTELEM)product; 431 temp = -temp; 432 } else { 433 product = (UDCTELEM2)(temp + corr) * recip; 434 product >>= shift + sizeof(DCTELEM)*8; 435 temp = (DCTELEM)product; 436 } 437 output_ptr[i] = (JCOEF) temp; 438 } 439 440 #else 441 442 register DCTELEM qval; 443 444 for (i = 0; i < DCTSIZE2; i++) { 445 qval = divisors[i]; 446 temp = workspace[i]; 447 /* Divide the coefficient value by qval, ensuring proper rounding. 448 * Since C does not specify the direction of rounding for negative 449 * quotients, we have to force the dividend positive for portability. 450 * 451 * In most files, at least half of the output values will be zero 452 * (at default quantization settings, more like three-quarters...) 453 * so we should ensure that this case is fast. On many machines, 454 * a comparison is enough cheaper than a divide to make a special test 455 * a win. Since both inputs will be nonnegative, we need only test 456 * for a < b to discover whether a/b is 0. 457 * If your machine's division is fast enough, define FAST_DIVIDE. 458 */ 459 #ifdef FAST_DIVIDE 460 #define DIVIDE_BY(a,b) a /= b 461 #else 462 #define DIVIDE_BY(a,b) if (a >= b) a /= b; else a = 0 463 #endif 464 if (temp < 0) { 465 temp = -temp; 466 temp += qval>>1; /* for rounding */ 467 DIVIDE_BY(temp, qval); 468 temp = -temp; 469 } else { 470 temp += qval>>1; /* for rounding */ 471 DIVIDE_BY(temp, qval); 472 } 473 output_ptr[i] = (JCOEF) temp; 474 } 475 476 #endif 477 478 } 479 480 481 /* 482 * Perform forward DCT on one or more blocks of a component. 483 * 484 * The input samples are taken from the sample_data[] array starting at 485 * position start_row/start_col, and moving to the right for any additional 486 * blocks. The quantized coefficients are returned in coef_blocks[]. 487 */ 488 489 METHODDEF(void) 490 forward_DCT (j_compress_ptr cinfo, jpeg_component_info *compptr, 491 JSAMPARRAY sample_data, JBLOCKROW coef_blocks, 492 JDIMENSION start_row, JDIMENSION start_col, 493 JDIMENSION num_blocks) 494 /* This version is used for integer DCT implementations. */ 495 { 496 /* This routine is heavily used, so it's worth coding it tightly. */ 497 my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; 498 DCTELEM *divisors = fdct->divisors[compptr->quant_tbl_no]; 499 DCTELEM *workspace; 500 JDIMENSION bi; 501 502 /* Make sure the compiler doesn't look up these every pass */ 503 forward_DCT_method_ptr do_dct = fdct->dct; 504 convsamp_method_ptr do_convsamp = fdct->convsamp; 505 quantize_method_ptr do_quantize = fdct->quantize; 506 workspace = fdct->workspace; 507 508 sample_data += start_row; /* fold in the vertical offset once */ 509 510 for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) { 511 /* Load data into workspace, applying unsigned->signed conversion */ 512 (*do_convsamp) (sample_data, start_col, workspace); 513 514 /* Perform the DCT */ 515 (*do_dct) (workspace); 516 517 /* Quantize/descale the coefficients, and store into coef_blocks[] */ 518 (*do_quantize) (coef_blocks[bi], divisors, workspace); 519 } 520 } 521 522 523 #ifdef DCT_FLOAT_SUPPORTED 524 525 526 METHODDEF(void) 527 convsamp_float (JSAMPARRAY sample_data, JDIMENSION start_col, FAST_FLOAT *workspace) 528 { 529 register FAST_FLOAT *workspaceptr; 530 register JSAMPROW elemptr; 531 register int elemr; 532 533 workspaceptr = workspace; 534 for (elemr = 0; elemr < DCTSIZE; elemr++) { 535 elemptr = sample_data[elemr] + start_col; 536 #if DCTSIZE == 8 /* unroll the inner loop */ 537 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 538 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 539 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 540 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 541 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 542 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 543 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 544 *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 545 #else 546 { 547 register int elemc; 548 for (elemc = DCTSIZE; elemc > 0; elemc--) 549 *workspaceptr++ = (FAST_FLOAT) 550 (GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); 551 } 552 #endif 553 } 554 } 555 556 557 METHODDEF(void) 558 quantize_float (JCOEFPTR coef_block, FAST_FLOAT *divisors, FAST_FLOAT *workspace) 559 { 560 register FAST_FLOAT temp; 561 register int i; 562 register JCOEFPTR output_ptr = coef_block; 563 564 for (i = 0; i < DCTSIZE2; i++) { 565 /* Apply the quantization and scaling factor */ 566 temp = workspace[i] * divisors[i]; 567 568 /* Round to nearest integer. 569 * Since C does not specify the direction of rounding for negative 570 * quotients, we have to force the dividend positive for portability. 571 * The maximum coefficient size is +-16K (for 12-bit data), so this 572 * code should work for either 16-bit or 32-bit ints. 573 */ 574 output_ptr[i] = (JCOEF) ((int) (temp + (FAST_FLOAT) 16384.5) - 16384); 575 } 576 } 577 578 579 METHODDEF(void) 580 forward_DCT_float (j_compress_ptr cinfo, jpeg_component_info *compptr, 581 JSAMPARRAY sample_data, JBLOCKROW coef_blocks, 582 JDIMENSION start_row, JDIMENSION start_col, 583 JDIMENSION num_blocks) 584 /* This version is used for floating-point DCT implementations. */ 585 { 586 /* This routine is heavily used, so it's worth coding it tightly. */ 587 my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; 588 FAST_FLOAT *divisors = fdct->float_divisors[compptr->quant_tbl_no]; 589 FAST_FLOAT *workspace; 590 JDIMENSION bi; 591 592 593 /* Make sure the compiler doesn't look up these every pass */ 594 float_DCT_method_ptr do_dct = fdct->float_dct; 595 float_convsamp_method_ptr do_convsamp = fdct->float_convsamp; 596 float_quantize_method_ptr do_quantize = fdct->float_quantize; 597 workspace = fdct->float_workspace; 598 599 sample_data += start_row; /* fold in the vertical offset once */ 600 601 for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) { 602 /* Load data into workspace, applying unsigned->signed conversion */ 603 (*do_convsamp) (sample_data, start_col, workspace); 604 605 /* Perform the DCT */ 606 (*do_dct) (workspace); 607 608 /* Quantize/descale the coefficients, and store into coef_blocks[] */ 609 (*do_quantize) (coef_blocks[bi], divisors, workspace); 610 } 611 } 612 613 #endif /* DCT_FLOAT_SUPPORTED */ 614 615 616 /* 617 * Initialize FDCT manager. 618 */ 619 620 GLOBAL(void) 621 jinit_forward_dct (j_compress_ptr cinfo) 622 { 623 my_fdct_ptr fdct; 624 int i; 625 626 fdct = (my_fdct_ptr) 627 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 628 sizeof(my_fdct_controller)); 629 cinfo->fdct = (struct jpeg_forward_dct *) fdct; 630 fdct->pub.start_pass = start_pass_fdctmgr; 631 632 /* First determine the DCT... */ 633 switch (cinfo->dct_method) { 634 #ifdef DCT_ISLOW_SUPPORTED 635 case JDCT_ISLOW: 636 fdct->pub.forward_DCT = forward_DCT; 637 if (jsimd_can_fdct_islow()) 638 fdct->dct = jsimd_fdct_islow; 639 else 640 fdct->dct = jpeg_fdct_islow; 641 break; 642 #endif 643 #ifdef DCT_IFAST_SUPPORTED 644 case JDCT_IFAST: 645 fdct->pub.forward_DCT = forward_DCT; 646 if (jsimd_can_fdct_ifast()) 647 fdct->dct = jsimd_fdct_ifast; 648 else 649 fdct->dct = jpeg_fdct_ifast; 650 break; 651 #endif 652 #ifdef DCT_FLOAT_SUPPORTED 653 case JDCT_FLOAT: 654 fdct->pub.forward_DCT = forward_DCT_float; 655 if (jsimd_can_fdct_float()) 656 fdct->float_dct = jsimd_fdct_float; 657 else 658 fdct->float_dct = jpeg_fdct_float; 659 break; 660 #endif 661 default: 662 ERREXIT(cinfo, JERR_NOT_COMPILED); 663 break; 664 } 665 666 /* ...then the supporting stages. */ 667 switch (cinfo->dct_method) { 668 #ifdef DCT_ISLOW_SUPPORTED 669 case JDCT_ISLOW: 670 #endif 671 #ifdef DCT_IFAST_SUPPORTED 672 case JDCT_IFAST: 673 #endif 674 #if defined(DCT_ISLOW_SUPPORTED) || defined(DCT_IFAST_SUPPORTED) 675 if (jsimd_can_convsamp()) 676 fdct->convsamp = jsimd_convsamp; 677 else 678 fdct->convsamp = convsamp; 679 if (jsimd_can_quantize()) 680 fdct->quantize = jsimd_quantize; 681 else 682 fdct->quantize = quantize; 683 break; 684 #endif 685 #ifdef DCT_FLOAT_SUPPORTED 686 case JDCT_FLOAT: 687 if (jsimd_can_convsamp_float()) 688 fdct->float_convsamp = jsimd_convsamp_float; 689 else 690 fdct->float_convsamp = convsamp_float; 691 if (jsimd_can_quantize_float()) 692 fdct->float_quantize = jsimd_quantize_float; 693 else 694 fdct->float_quantize = quantize_float; 695 break; 696 #endif 697 default: 698 ERREXIT(cinfo, JERR_NOT_COMPILED); 699 break; 700 } 701 702 /* Allocate workspace memory */ 703 #ifdef DCT_FLOAT_SUPPORTED 704 if (cinfo->dct_method == JDCT_FLOAT) 705 fdct->float_workspace = (FAST_FLOAT *) 706 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 707 sizeof(FAST_FLOAT) * DCTSIZE2); 708 else 709 #endif 710 fdct->workspace = (DCTELEM *) 711 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 712 sizeof(DCTELEM) * DCTSIZE2); 713 714 /* Mark divisor tables unallocated */ 715 for (i = 0; i < NUM_QUANT_TBLS; i++) { 716 fdct->divisors[i] = NULL; 717 #ifdef DCT_FLOAT_SUPPORTED 718 fdct->float_divisors[i] = NULL; 719 #endif 720 } 721 } 722
