1 #if !defined(_FX_JPEG_TURBO_) 2 /* 3 * jdcoefct.c 4 * 5 * Copyright (C) 1994-1997, Thomas G. Lane. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains the coefficient buffer controller for decompression. 10 * This controller is the top level of the JPEG decompressor proper. 11 * The coefficient buffer lies between entropy decoding and inverse-DCT steps. 12 * 13 * In buffered-image mode, this controller is the interface between 14 * input-oriented processing and output-oriented processing. 15 * Also, the input side (only) is used when reading a file for transcoding. 16 */ 17 18 #define JPEG_INTERNALS 19 #include "jinclude.h" 20 #include "jpeglib.h" 21 22 /* Block smoothing is only applicable for progressive JPEG, so: */ 23 #ifndef D_PROGRESSIVE_SUPPORTED 24 #undef BLOCK_SMOOTHING_SUPPORTED 25 #endif 26 27 /* Private buffer controller object */ 28 29 typedef struct { 30 struct jpeg_d_coef_controller pub; /* public fields */ 31 32 /* These variables keep track of the current location of the input side. */ 33 /* cinfo->input_iMCU_row is also used for this. */ 34 JDIMENSION MCU_ctr; /* counts MCUs processed in current row */ 35 int MCU_vert_offset; /* counts MCU rows within iMCU row */ 36 int MCU_rows_per_iMCU_row; /* number of such rows needed */ 37 38 /* The output side's location is represented by cinfo->output_iMCU_row. */ 39 40 /* In single-pass modes, it's sufficient to buffer just one MCU. 41 * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks, 42 * and let the entropy decoder write into that workspace each time. 43 * (On 80x86, the workspace is FAR even though it's not really very big; 44 * this is to keep the module interfaces unchanged when a large coefficient 45 * buffer is necessary.) 46 * In multi-pass modes, this array points to the current MCU's blocks 47 * within the virtual arrays; it is used only by the input side. 48 */ 49 JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU]; 50 51 #ifdef D_MULTISCAN_FILES_SUPPORTED 52 /* In multi-pass modes, we need a virtual block array for each component. */ 53 jvirt_barray_ptr whole_image[MAX_COMPONENTS]; 54 #endif 55 56 #ifdef BLOCK_SMOOTHING_SUPPORTED 57 /* When doing block smoothing, we latch coefficient Al values here */ 58 int * coef_bits_latch; 59 #define SAVED_COEFS 6 /* we save coef_bits[0..5] */ 60 #endif 61 } my_coef_controller; 62 63 typedef my_coef_controller * my_coef_ptr; 64 65 /* Forward declarations */ 66 METHODDEF(int) decompress_onepass 67 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); 68 #ifdef D_MULTISCAN_FILES_SUPPORTED 69 METHODDEF(int) decompress_data 70 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); 71 #endif 72 #ifdef BLOCK_SMOOTHING_SUPPORTED 73 LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo)); 74 METHODDEF(int) decompress_smooth_data 75 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); 76 #endif 77 78 79 LOCAL(void) 80 start_iMCU_row (j_decompress_ptr cinfo) 81 /* Reset within-iMCU-row counters for a new row (input side) */ 82 { 83 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 84 85 /* In an interleaved scan, an MCU row is the same as an iMCU row. 86 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. 87 * But at the bottom of the image, process only what's left. 88 */ 89 if (cinfo->comps_in_scan > 1) { 90 coef->MCU_rows_per_iMCU_row = 1; 91 } else { 92 if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1)) 93 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; 94 else 95 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; 96 } 97 98 coef->MCU_ctr = 0; 99 coef->MCU_vert_offset = 0; 100 } 101 102 103 /* 104 * Initialize for an input processing pass. 105 */ 106 107 METHODDEF(void) 108 start_input_pass (j_decompress_ptr cinfo) 109 { 110 cinfo->input_iMCU_row = 0; 111 start_iMCU_row(cinfo); 112 } 113 114 115 /* 116 * Initialize for an output processing pass. 117 */ 118 119 METHODDEF(void) 120 start_output_pass (j_decompress_ptr cinfo) 121 { 122 #ifdef BLOCK_SMOOTHING_SUPPORTED 123 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 124 125 /* If multipass, check to see whether to use block smoothing on this pass */ 126 if (coef->pub.coef_arrays != NULL) { 127 if (cinfo->do_block_smoothing && smoothing_ok(cinfo)) 128 coef->pub.decompress_data = decompress_smooth_data; 129 else 130 coef->pub.decompress_data = decompress_data; 131 } 132 #endif 133 cinfo->output_iMCU_row = 0; 134 } 135 136 137 /* 138 * Decompress and return some data in the single-pass case. 139 * Always attempts to emit one fully interleaved MCU row ("iMCU" row). 140 * Input and output must run in lockstep since we have only a one-MCU buffer. 141 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. 142 * 143 * NB: output_buf contains a plane for each component in image, 144 * which we index according to the component's SOF position. 145 */ 146 147 METHODDEF(int) 148 decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) 149 { 150 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 151 JDIMENSION MCU_col_num; /* index of current MCU within row */ 152 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; 153 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 154 int blkn, ci, xindex, yindex, yoffset, useful_width; 155 JSAMPARRAY output_ptr; 156 JDIMENSION start_col, output_col; 157 jpeg_component_info *compptr; 158 inverse_DCT_method_ptr inverse_DCT; 159 160 /* Loop to process as much as one whole iMCU row */ 161 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 162 yoffset++) { 163 for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col; 164 MCU_col_num++) { 165 /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */ 166 jzero_far((void FAR *) coef->MCU_buffer[0], 167 (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK))); 168 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { 169 /* Suspension forced; update state counters and exit */ 170 coef->MCU_vert_offset = yoffset; 171 coef->MCU_ctr = MCU_col_num; 172 return JPEG_SUSPENDED; 173 } 174 /* Determine where data should go in output_buf and do the IDCT thing. 175 * We skip dummy blocks at the right and bottom edges (but blkn gets 176 * incremented past them!). Note the inner loop relies on having 177 * allocated the MCU_buffer[] blocks sequentially. 178 */ 179 blkn = 0; /* index of current DCT block within MCU */ 180 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 181 compptr = cinfo->cur_comp_info[ci]; 182 /* Don't bother to IDCT an uninteresting component. */ 183 if (! compptr->component_needed) { 184 blkn += compptr->MCU_blocks; 185 continue; 186 } 187 inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index]; 188 useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width 189 : compptr->last_col_width; 190 output_ptr = output_buf[compptr->component_index] + 191 yoffset * compptr->DCT_scaled_size; 192 start_col = MCU_col_num * compptr->MCU_sample_width; 193 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 194 if (cinfo->input_iMCU_row < last_iMCU_row || 195 yoffset+yindex < compptr->last_row_height) { 196 output_col = start_col; 197 for (xindex = 0; xindex < useful_width; xindex++) { 198 (*inverse_DCT) (cinfo, compptr, 199 (JCOEFPTR) coef->MCU_buffer[blkn+xindex], 200 output_ptr, output_col); 201 output_col += compptr->DCT_scaled_size; 202 } 203 } 204 blkn += compptr->MCU_width; 205 output_ptr += compptr->DCT_scaled_size; 206 } 207 } 208 } 209 /* Completed an MCU row, but perhaps not an iMCU row */ 210 coef->MCU_ctr = 0; 211 } 212 /* Completed the iMCU row, advance counters for next one */ 213 cinfo->output_iMCU_row++; 214 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { 215 start_iMCU_row(cinfo); 216 return JPEG_ROW_COMPLETED; 217 } 218 /* Completed the scan */ 219 (*cinfo->inputctl->finish_input_pass) (cinfo); 220 return JPEG_SCAN_COMPLETED; 221 } 222 223 224 /* 225 * Dummy consume-input routine for single-pass operation. 226 */ 227 228 METHODDEF(int) 229 dummy_consume_data (j_decompress_ptr cinfo) 230 { 231 return JPEG_SUSPENDED; /* Always indicate nothing was done */ 232 } 233 234 235 #ifdef D_MULTISCAN_FILES_SUPPORTED 236 237 /* 238 * Consume input data and store it in the full-image coefficient buffer. 239 * We read as much as one fully interleaved MCU row ("iMCU" row) per call, 240 * ie, v_samp_factor block rows for each component in the scan. 241 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. 242 */ 243 244 METHODDEF(int) 245 consume_data (j_decompress_ptr cinfo) 246 { 247 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 248 JDIMENSION MCU_col_num; /* index of current MCU within row */ 249 int blkn, ci, xindex, yindex, yoffset; 250 JDIMENSION start_col; 251 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; 252 JBLOCKROW buffer_ptr; 253 jpeg_component_info *compptr; 254 255 /* Align the virtual buffers for the components used in this scan. */ 256 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 257 compptr = cinfo->cur_comp_info[ci]; 258 buffer[ci] = (*cinfo->mem->access_virt_barray) 259 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], 260 cinfo->input_iMCU_row * compptr->v_samp_factor, 261 (JDIMENSION) compptr->v_samp_factor, TRUE); 262 /* Note: entropy decoder expects buffer to be zeroed, 263 * but this is handled automatically by the memory manager 264 * because we requested a pre-zeroed array. 265 */ 266 } 267 268 /* Loop to process one whole iMCU row */ 269 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 270 yoffset++) { 271 for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row; 272 MCU_col_num++) { 273 /* Construct list of pointers to DCT blocks belonging to this MCU */ 274 blkn = 0; /* index of current DCT block within MCU */ 275 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 276 compptr = cinfo->cur_comp_info[ci]; 277 start_col = MCU_col_num * compptr->MCU_width; 278 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 279 buffer_ptr = buffer[ci][yindex+yoffset] + start_col; 280 for (xindex = 0; xindex < compptr->MCU_width; xindex++) { 281 coef->MCU_buffer[blkn++] = buffer_ptr++; 282 } 283 } 284 } 285 /* Try to fetch the MCU. */ 286 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { 287 /* Suspension forced; update state counters and exit */ 288 coef->MCU_vert_offset = yoffset; 289 coef->MCU_ctr = MCU_col_num; 290 return JPEG_SUSPENDED; 291 } 292 } 293 /* Completed an MCU row, but perhaps not an iMCU row */ 294 coef->MCU_ctr = 0; 295 } 296 /* Completed the iMCU row, advance counters for next one */ 297 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { 298 start_iMCU_row(cinfo); 299 return JPEG_ROW_COMPLETED; 300 } 301 /* Completed the scan */ 302 (*cinfo->inputctl->finish_input_pass) (cinfo); 303 return JPEG_SCAN_COMPLETED; 304 } 305 306 307 /* 308 * Decompress and return some data in the multi-pass case. 309 * Always attempts to emit one fully interleaved MCU row ("iMCU" row). 310 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. 311 * 312 * NB: output_buf contains a plane for each component in image. 313 */ 314 315 METHODDEF(int) 316 decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) 317 { 318 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 319 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 320 JDIMENSION block_num; 321 int ci, block_row, block_rows; 322 JBLOCKARRAY buffer; 323 JBLOCKROW buffer_ptr; 324 JSAMPARRAY output_ptr; 325 JDIMENSION output_col; 326 jpeg_component_info *compptr; 327 inverse_DCT_method_ptr inverse_DCT; 328 329 /* Force some input to be done if we are getting ahead of the input. */ 330 while (cinfo->input_scan_number < cinfo->output_scan_number || 331 (cinfo->input_scan_number == cinfo->output_scan_number && 332 cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) { 333 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED) 334 return JPEG_SUSPENDED; 335 } 336 337 /* OK, output from the virtual arrays. */ 338 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 339 ci++, compptr++) { 340 /* Don't bother to IDCT an uninteresting component. */ 341 if (! compptr->component_needed) 342 continue; 343 /* Align the virtual buffer for this component. */ 344 buffer = (*cinfo->mem->access_virt_barray) 345 ((j_common_ptr) cinfo, coef->whole_image[ci], 346 cinfo->output_iMCU_row * compptr->v_samp_factor, 347 (JDIMENSION) compptr->v_samp_factor, FALSE); 348 /* Count non-dummy DCT block rows in this iMCU row. */ 349 if (cinfo->output_iMCU_row < last_iMCU_row) 350 block_rows = compptr->v_samp_factor; 351 else { 352 /* NB: can't use last_row_height here; it is input-side-dependent! */ 353 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 354 if (block_rows == 0) block_rows = compptr->v_samp_factor; 355 } 356 inverse_DCT = cinfo->idct->inverse_DCT[ci]; 357 output_ptr = output_buf[ci]; 358 /* Loop over all DCT blocks to be processed. */ 359 for (block_row = 0; block_row < block_rows; block_row++) { 360 buffer_ptr = buffer[block_row]; 361 output_col = 0; 362 for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) { 363 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr, 364 output_ptr, output_col); 365 buffer_ptr++; 366 output_col += compptr->DCT_scaled_size; 367 } 368 output_ptr += compptr->DCT_scaled_size; 369 } 370 } 371 372 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows) 373 return JPEG_ROW_COMPLETED; 374 return JPEG_SCAN_COMPLETED; 375 } 376 377 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 378 379 380 #ifdef BLOCK_SMOOTHING_SUPPORTED 381 382 /* 383 * This code applies interblock smoothing as described by section K.8 384 * of the JPEG standard: the first 5 AC coefficients are estimated from 385 * the DC values of a DCT block and its 8 neighboring blocks. 386 * We apply smoothing only for progressive JPEG decoding, and only if 387 * the coefficients it can estimate are not yet known to full precision. 388 */ 389 390 /* Natural-order array positions of the first 5 zigzag-order coefficients */ 391 #define Q01_POS 1 392 #define Q10_POS 8 393 #define Q20_POS 16 394 #define Q11_POS 9 395 #define Q02_POS 2 396 397 /* 398 * Determine whether block smoothing is applicable and safe. 399 * We also latch the current states of the coef_bits[] entries for the 400 * AC coefficients; otherwise, if the input side of the decompressor 401 * advances into a new scan, we might think the coefficients are known 402 * more accurately than they really are. 403 */ 404 405 LOCAL(boolean) 406 smoothing_ok (j_decompress_ptr cinfo) 407 { 408 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 409 boolean smoothing_useful = FALSE; 410 int ci, coefi; 411 jpeg_component_info *compptr; 412 JQUANT_TBL * qtable; 413 int * coef_bits; 414 int * coef_bits_latch; 415 416 if (! cinfo->progressive_mode || cinfo->coef_bits == NULL) 417 return FALSE; 418 419 /* Allocate latch area if not already done */ 420 if (coef->coef_bits_latch == NULL) 421 coef->coef_bits_latch = (int *) 422 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 423 cinfo->num_components * 424 (SAVED_COEFS * SIZEOF(int))); 425 coef_bits_latch = coef->coef_bits_latch; 426 427 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 428 ci++, compptr++) { 429 /* All components' quantization values must already be latched. */ 430 if ((qtable = compptr->quant_table) == NULL) 431 return FALSE; 432 /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */ 433 if (qtable->quantval[0] == 0 || 434 qtable->quantval[Q01_POS] == 0 || 435 qtable->quantval[Q10_POS] == 0 || 436 qtable->quantval[Q20_POS] == 0 || 437 qtable->quantval[Q11_POS] == 0 || 438 qtable->quantval[Q02_POS] == 0) 439 return FALSE; 440 /* DC values must be at least partly known for all components. */ 441 coef_bits = cinfo->coef_bits[ci]; 442 if (coef_bits[0] < 0) 443 return FALSE; 444 /* Block smoothing is helpful if some AC coefficients remain inaccurate. */ 445 for (coefi = 1; coefi <= 5; coefi++) { 446 coef_bits_latch[coefi] = coef_bits[coefi]; 447 if (coef_bits[coefi] != 0) 448 smoothing_useful = TRUE; 449 } 450 coef_bits_latch += SAVED_COEFS; 451 } 452 453 return smoothing_useful; 454 } 455 456 457 /* 458 * Variant of decompress_data for use when doing block smoothing. 459 */ 460 461 METHODDEF(int) 462 decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) 463 { 464 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 465 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 466 JDIMENSION block_num, last_block_column; 467 int ci, block_row, block_rows, access_rows; 468 JBLOCKARRAY buffer; 469 JBLOCKROW buffer_ptr, prev_block_row, next_block_row; 470 JSAMPARRAY output_ptr; 471 JDIMENSION output_col; 472 jpeg_component_info *compptr; 473 inverse_DCT_method_ptr inverse_DCT; 474 boolean first_row, last_row; 475 JBLOCK workspace; 476 int *coef_bits; 477 JQUANT_TBL *quanttbl; 478 INT32 Q00,Q01,Q02,Q10,Q11,Q20, num; 479 int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9; 480 int Al, pred; 481 482 /* Force some input to be done if we are getting ahead of the input. */ 483 while (cinfo->input_scan_number <= cinfo->output_scan_number && 484 ! cinfo->inputctl->eoi_reached) { 485 if (cinfo->input_scan_number == cinfo->output_scan_number) { 486 /* If input is working on current scan, we ordinarily want it to 487 * have completed the current row. But if input scan is DC, 488 * we want it to keep one row ahead so that next block row's DC 489 * values are up to date. 490 */ 491 JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0; 492 if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta) 493 break; 494 } 495 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED) 496 return JPEG_SUSPENDED; 497 } 498 499 /* OK, output from the virtual arrays. */ 500 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 501 ci++, compptr++) { 502 /* Don't bother to IDCT an uninteresting component. */ 503 if (! compptr->component_needed) 504 continue; 505 /* Count non-dummy DCT block rows in this iMCU row. */ 506 if (cinfo->output_iMCU_row < last_iMCU_row) { 507 block_rows = compptr->v_samp_factor; 508 access_rows = block_rows * 2; /* this and next iMCU row */ 509 last_row = FALSE; 510 } else { 511 /* NB: can't use last_row_height here; it is input-side-dependent! */ 512 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 513 if (block_rows == 0) block_rows = compptr->v_samp_factor; 514 access_rows = block_rows; /* this iMCU row only */ 515 last_row = TRUE; 516 } 517 /* Align the virtual buffer for this component. */ 518 if (cinfo->output_iMCU_row > 0) { 519 access_rows += compptr->v_samp_factor; /* prior iMCU row too */ 520 buffer = (*cinfo->mem->access_virt_barray) 521 ((j_common_ptr) cinfo, coef->whole_image[ci], 522 (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor, 523 (JDIMENSION) access_rows, FALSE); 524 buffer += compptr->v_samp_factor; /* point to current iMCU row */ 525 first_row = FALSE; 526 } else { 527 buffer = (*cinfo->mem->access_virt_barray) 528 ((j_common_ptr) cinfo, coef->whole_image[ci], 529 (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE); 530 first_row = TRUE; 531 } 532 /* Fetch component-dependent info */ 533 coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS); 534 quanttbl = compptr->quant_table; 535 Q00 = quanttbl->quantval[0]; 536 Q01 = quanttbl->quantval[Q01_POS]; 537 Q10 = quanttbl->quantval[Q10_POS]; 538 Q20 = quanttbl->quantval[Q20_POS]; 539 Q11 = quanttbl->quantval[Q11_POS]; 540 Q02 = quanttbl->quantval[Q02_POS]; 541 inverse_DCT = cinfo->idct->inverse_DCT[ci]; 542 output_ptr = output_buf[ci]; 543 /* Loop over all DCT blocks to be processed. */ 544 for (block_row = 0; block_row < block_rows; block_row++) { 545 buffer_ptr = buffer[block_row]; 546 if (first_row && block_row == 0) 547 prev_block_row = buffer_ptr; 548 else 549 prev_block_row = buffer[block_row-1]; 550 if (last_row && block_row == block_rows-1) 551 next_block_row = buffer_ptr; 552 else 553 next_block_row = buffer[block_row+1]; 554 /* We fetch the surrounding DC values using a sliding-register approach. 555 * Initialize all nine here so as to do the right thing on narrow pics. 556 */ 557 DC1 = DC2 = DC3 = (int) prev_block_row[0][0]; 558 DC4 = DC5 = DC6 = (int) buffer_ptr[0][0]; 559 DC7 = DC8 = DC9 = (int) next_block_row[0][0]; 560 output_col = 0; 561 last_block_column = compptr->width_in_blocks - 1; 562 for (block_num = 0; block_num <= last_block_column; block_num++) { 563 /* Fetch current DCT block into workspace so we can modify it. */ 564 jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1); 565 /* Update DC values */ 566 if (block_num < last_block_column) { 567 DC3 = (int) prev_block_row[1][0]; 568 DC6 = (int) buffer_ptr[1][0]; 569 DC9 = (int) next_block_row[1][0]; 570 } 571 /* Compute coefficient estimates per K.8. 572 * An estimate is applied only if coefficient is still zero, 573 * and is not known to be fully accurate. 574 */ 575 /* AC01 */ 576 if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) { 577 num = 36 * Q00 * (DC4 - DC6); 578 if (num >= 0) { 579 pred = (int) (((Q01<<7) + num) / (Q01<<8)); 580 if (Al > 0 && pred >= (1<<Al)) 581 pred = (1<<Al)-1; 582 } else { 583 pred = (int) (((Q01<<7) - num) / (Q01<<8)); 584 if (Al > 0 && pred >= (1<<Al)) 585 pred = (1<<Al)-1; 586 pred = -pred; 587 } 588 workspace[1] = (JCOEF) pred; 589 } 590 /* AC10 */ 591 if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) { 592 num = 36 * Q00 * (DC2 - DC8); 593 if (num >= 0) { 594 pred = (int) (((Q10<<7) + num) / (Q10<<8)); 595 if (Al > 0 && pred >= (1<<Al)) 596 pred = (1<<Al)-1; 597 } else { 598 pred = (int) (((Q10<<7) - num) / (Q10<<8)); 599 if (Al > 0 && pred >= (1<<Al)) 600 pred = (1<<Al)-1; 601 pred = -pred; 602 } 603 workspace[8] = (JCOEF) pred; 604 } 605 /* AC20 */ 606 if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) { 607 num = 9 * Q00 * (DC2 + DC8 - 2*DC5); 608 if (num >= 0) { 609 pred = (int) (((Q20<<7) + num) / (Q20<<8)); 610 if (Al > 0 && pred >= (1<<Al)) 611 pred = (1<<Al)-1; 612 } else { 613 pred = (int) (((Q20<<7) - num) / (Q20<<8)); 614 if (Al > 0 && pred >= (1<<Al)) 615 pred = (1<<Al)-1; 616 pred = -pred; 617 } 618 workspace[16] = (JCOEF) pred; 619 } 620 /* AC11 */ 621 if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) { 622 num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9); 623 if (num >= 0) { 624 pred = (int) (((Q11<<7) + num) / (Q11<<8)); 625 if (Al > 0 && pred >= (1<<Al)) 626 pred = (1<<Al)-1; 627 } else { 628 pred = (int) (((Q11<<7) - num) / (Q11<<8)); 629 if (Al > 0 && pred >= (1<<Al)) 630 pred = (1<<Al)-1; 631 pred = -pred; 632 } 633 workspace[9] = (JCOEF) pred; 634 } 635 /* AC02 */ 636 if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) { 637 num = 9 * Q00 * (DC4 + DC6 - 2*DC5); 638 if (num >= 0) { 639 pred = (int) (((Q02<<7) + num) / (Q02<<8)); 640 if (Al > 0 && pred >= (1<<Al)) 641 pred = (1<<Al)-1; 642 } else { 643 pred = (int) (((Q02<<7) - num) / (Q02<<8)); 644 if (Al > 0 && pred >= (1<<Al)) 645 pred = (1<<Al)-1; 646 pred = -pred; 647 } 648 workspace[2] = (JCOEF) pred; 649 } 650 /* OK, do the IDCT */ 651 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace, 652 output_ptr, output_col); 653 /* Advance for next column */ 654 DC1 = DC2; DC2 = DC3; 655 DC4 = DC5; DC5 = DC6; 656 DC7 = DC8; DC8 = DC9; 657 buffer_ptr++, prev_block_row++, next_block_row++; 658 output_col += compptr->DCT_scaled_size; 659 } 660 output_ptr += compptr->DCT_scaled_size; 661 } 662 } 663 664 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows) 665 return JPEG_ROW_COMPLETED; 666 return JPEG_SCAN_COMPLETED; 667 } 668 669 #endif /* BLOCK_SMOOTHING_SUPPORTED */ 670 671 672 /* 673 * Initialize coefficient buffer controller. 674 */ 675 676 GLOBAL(void) 677 jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer) 678 { 679 my_coef_ptr coef; 680 681 coef = (my_coef_ptr) 682 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 683 SIZEOF(my_coef_controller)); 684 cinfo->coef = (struct jpeg_d_coef_controller *) coef; 685 coef->pub.start_input_pass = start_input_pass; 686 coef->pub.start_output_pass = start_output_pass; 687 #ifdef BLOCK_SMOOTHING_SUPPORTED 688 coef->coef_bits_latch = NULL; 689 #endif 690 691 /* Create the coefficient buffer. */ 692 if (need_full_buffer) { 693 #ifdef D_MULTISCAN_FILES_SUPPORTED 694 /* Allocate a full-image virtual array for each component, */ 695 /* padded to a multiple of samp_factor DCT blocks in each direction. */ 696 /* Note we ask for a pre-zeroed array. */ 697 int ci, access_rows; 698 jpeg_component_info *compptr; 699 700 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 701 ci++, compptr++) { 702 access_rows = compptr->v_samp_factor; 703 #ifdef BLOCK_SMOOTHING_SUPPORTED 704 /* If block smoothing could be used, need a bigger window */ 705 if (cinfo->progressive_mode) 706 access_rows *= 3; 707 #endif 708 coef->whole_image[ci] = (*cinfo->mem->request_virt_barray) 709 ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE, 710 (JDIMENSION) jround_up((long) compptr->width_in_blocks, 711 (long) compptr->h_samp_factor), 712 (JDIMENSION) jround_up((long) compptr->height_in_blocks, 713 (long) compptr->v_samp_factor), 714 (JDIMENSION) access_rows); 715 } 716 coef->pub.consume_data = consume_data; 717 coef->pub.decompress_data = decompress_data; 718 coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */ 719 #else 720 ERREXIT(cinfo, JERR_NOT_COMPILED); 721 #endif 722 } else { 723 /* We only need a single-MCU buffer. */ 724 JBLOCKROW buffer; 725 int i; 726 727 buffer = (JBLOCKROW) 728 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 729 D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 730 for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) { 731 coef->MCU_buffer[i] = buffer + i; 732 } 733 coef->pub.consume_data = dummy_consume_data; 734 coef->pub.decompress_data = decompress_onepass; 735 coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */ 736 } 737 } 738 739 #endif //_FX_JPEG_TURBO_ 740
