1 /* 2 * jdcoefct.c 3 * 4 * Copyright (C) 1994-1997, 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 file contains the coefficient buffer controller for decompression. 9 * This controller is the top level of the JPEG decompressor proper. 10 * The coefficient buffer lies between entropy decoding and inverse-DCT steps. 11 * 12 * In buffered-image mode, this controller is the interface between 13 * input-oriented processing and output-oriented processing. 14 * Also, the input side (only) is used when reading a file for transcoding. 15 */ 16 17 #define JPEG_INTERNALS 18 #include "jinclude.h" 19 #include "jpeglib.h" 20 21 /* Block smoothing is only applicable for progressive JPEG, so: */ 22 #ifndef D_PROGRESSIVE_SUPPORTED 23 #undef BLOCK_SMOOTHING_SUPPORTED 24 #endif 25 26 /* Private buffer controller object */ 27 28 typedef struct { 29 struct jpeg_d_coef_controller pub; /* public fields */ 30 31 /* These variables keep track of the current location of the input side. */ 32 /* cinfo->input_iMCU_row is also used for this. */ 33 JDIMENSION MCU_ctr; /* counts MCUs processed in current row */ 34 int MCU_vert_offset; /* counts MCU rows within iMCU row */ 35 int MCU_rows_per_iMCU_row; /* number of such rows needed */ 36 37 /* The output side's location is represented by cinfo->output_iMCU_row. */ 38 39 /* In single-pass modes, it's sufficient to buffer just one MCU. 40 * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks, 41 * and let the entropy decoder write into that workspace each time. 42 * (On 80x86, the workspace is FAR even though it's not really very big; 43 * this is to keep the module interfaces unchanged when a large coefficient 44 * buffer is necessary.) 45 * In multi-pass modes, this array points to the current MCU's blocks 46 * within the virtual arrays; it is used only by the input side. 47 */ 48 JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU]; 49 50 #ifdef D_MULTISCAN_FILES_SUPPORTED 51 /* In multi-pass modes, we need a virtual block array for each component. */ 52 jvirt_barray_ptr whole_image[MAX_COMPONENTS]; 53 #endif 54 55 #ifdef BLOCK_SMOOTHING_SUPPORTED 56 /* When doing block smoothing, we latch coefficient Al values here */ 57 int * coef_bits_latch; 58 #define SAVED_COEFS 6 /* we save coef_bits[0..5] */ 59 #endif 60 } my_coef_controller; 61 62 typedef my_coef_controller * my_coef_ptr; 63 64 /* Forward declarations */ 65 METHODDEF(int) decompress_onepass 66 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); 67 #ifdef D_MULTISCAN_FILES_SUPPORTED 68 METHODDEF(int) decompress_data 69 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); 70 #endif 71 #ifdef BLOCK_SMOOTHING_SUPPORTED 72 LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo)); 73 METHODDEF(int) decompress_smooth_data 74 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); 75 #endif 76 77 78 LOCAL(void) 79 start_iMCU_row (j_decompress_ptr cinfo) 80 /* Reset within-iMCU-row counters for a new row (input side) */ 81 { 82 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 83 84 /* In an interleaved scan, an MCU row is the same as an iMCU row. 85 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. 86 * But at the bottom of the image, process only what's left. 87 */ 88 if (cinfo->comps_in_scan > 1) { 89 coef->MCU_rows_per_iMCU_row = 1; 90 } else { 91 if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1)) 92 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; 93 else 94 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; 95 } 96 97 coef->MCU_ctr = 0; 98 coef->MCU_vert_offset = 0; 99 } 100 101 102 /* 103 * Initialize for an input processing pass. 104 */ 105 106 METHODDEF(void) 107 start_input_pass (j_decompress_ptr cinfo) 108 { 109 cinfo->input_iMCU_row = 0; 110 start_iMCU_row(cinfo); 111 } 112 113 114 /* 115 * Initialize for an output processing pass. 116 */ 117 118 METHODDEF(void) 119 start_output_pass (j_decompress_ptr cinfo) 120 { 121 #ifdef BLOCK_SMOOTHING_SUPPORTED 122 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 123 124 /* If multipass, check to see whether to use block smoothing on this pass */ 125 if (coef->pub.coef_arrays != NULL) { 126 if (cinfo->do_block_smoothing && smoothing_ok(cinfo)) 127 coef->pub.decompress_data = decompress_smooth_data; 128 else 129 coef->pub.decompress_data = decompress_data; 130 } 131 #endif 132 cinfo->output_iMCU_row = 0; 133 } 134 135 136 /* 137 * Decompress and return some data in the single-pass case. 138 * Always attempts to emit one fully interleaved MCU row ("iMCU" row). 139 * Input and output must run in lockstep since we have only a one-MCU buffer. 140 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. 141 * 142 * NB: output_buf contains a plane for each component in image, 143 * which we index according to the component's SOF position. 144 */ 145 146 METHODDEF(int) 147 decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) 148 { 149 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 150 JDIMENSION MCU_col_num; /* index of current MCU within row */ 151 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; 152 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 153 int blkn, ci, xindex, yindex, yoffset, useful_width; 154 JSAMPARRAY output_ptr; 155 JDIMENSION start_col, output_col; 156 jpeg_component_info *compptr; 157 inverse_DCT_method_ptr inverse_DCT; 158 159 #ifdef ANDROID_TILE_BASED_DECODE 160 if (cinfo->tile_decode) { 161 last_MCU_col = 162 (cinfo->coef->MCU_column_right_boundary - 163 cinfo->coef->MCU_column_left_boundary) - 1; 164 } 165 #endif 166 167 /* Loop to process as much as one whole iMCU row */ 168 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 169 yoffset++) { 170 for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col; 171 MCU_col_num++) { 172 /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */ 173 if (MCU_col_num < coef->pub.MCU_columns_to_skip) { 174 (*cinfo->entropy->decode_mcu_discard_coef) (cinfo); 175 continue; 176 } else { 177 jzero_far((void FAR *) coef->MCU_buffer[0], 178 (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK))); 179 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { 180 /* Suspension forced; update state counters and exit */ 181 coef->MCU_vert_offset = yoffset; 182 coef->MCU_ctr = MCU_col_num; 183 return JPEG_SUSPENDED; 184 } 185 } 186 /* Determine where data should go in output_buf and do the IDCT thing. 187 * We skip dummy blocks at the right and bottom edges (but blkn gets 188 * incremented past them!). Note the inner loop relies on having 189 * allocated the MCU_buffer[] blocks sequentially. 190 */ 191 blkn = 0; /* index of current DCT block within MCU */ 192 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 193 compptr = cinfo->cur_comp_info[ci]; 194 /* Don't bother to IDCT an uninteresting component. */ 195 if (! compptr->component_needed) { 196 blkn += compptr->MCU_blocks; 197 continue; 198 } 199 inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index]; 200 useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width 201 : compptr->last_col_width; 202 output_ptr = output_buf[compptr->component_index] + 203 yoffset * compptr->DCT_scaled_size; 204 start_col = MCU_col_num * compptr->MCU_sample_width; 205 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 206 if (cinfo->input_iMCU_row < last_iMCU_row || 207 yoffset+yindex < compptr->last_row_height) { 208 output_col = start_col; 209 for (xindex = 0; xindex < useful_width; xindex++) { 210 (*inverse_DCT) (cinfo, compptr, 211 (JCOEFPTR) coef->MCU_buffer[blkn+xindex], 212 output_ptr, output_col); 213 output_col += compptr->DCT_scaled_size; 214 } 215 } 216 blkn += compptr->MCU_width; 217 output_ptr += compptr->DCT_scaled_size; 218 } 219 } 220 } 221 /* Completed an MCU row, but perhaps not an iMCU row */ 222 coef->MCU_ctr = 0; 223 } 224 /* Completed the iMCU row, advance counters for next one */ 225 cinfo->output_iMCU_row++; 226 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { 227 start_iMCU_row(cinfo); 228 return JPEG_ROW_COMPLETED; 229 } 230 /* Completed the scan */ 231 (*cinfo->inputctl->finish_input_pass) (cinfo); 232 return JPEG_SCAN_COMPLETED; 233 } 234 235 236 /* 237 * Dummy consume-input routine for single-pass operation. 238 */ 239 240 METHODDEF(int) 241 dummy_consume_data (j_decompress_ptr cinfo) 242 { 243 return JPEG_SUSPENDED; /* Always indicate nothing was done */ 244 } 245 246 #ifdef D_MULTISCAN_FILES_SUPPORTED 247 /* 248 * Consume input data and store it in the full-image coefficient buffer. 249 * We read as much as one fully interleaved MCU row ("iMCU" row) per call, 250 * ie, v_samp_factor block rows for each component in the scan. 251 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. 252 */ 253 254 METHODDEF(int) 255 consume_data (j_decompress_ptr cinfo) 256 { 257 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 258 JDIMENSION MCU_col_num; /* index of current MCU within row */ 259 int blkn, ci, xindex, yindex, yoffset; 260 JDIMENSION start_col; 261 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; 262 JBLOCKROW buffer_ptr; 263 jpeg_component_info *compptr; 264 265 /* Align the virtual buffers for the components used in this scan. */ 266 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 267 compptr = cinfo->cur_comp_info[ci]; 268 buffer[ci] = (*cinfo->mem->access_virt_barray) 269 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], 270 cinfo->tile_decode ? 0 : cinfo->input_iMCU_row * compptr->v_samp_factor, 271 (JDIMENSION) compptr->v_samp_factor, TRUE); 272 /* Note: entropy decoder expects buffer to be zeroed, 273 * but this is handled automatically by the memory manager 274 * because we requested a pre-zeroed array. 275 */ 276 } 277 unsigned int MCUs_per_row = cinfo->MCUs_per_row; 278 #ifdef ANDROID_TILE_BASED_DECODE 279 if (cinfo->tile_decode) { 280 int iMCU_width_To_MCU_width; 281 if (cinfo->comps_in_scan > 1) { 282 // Interleaved 283 iMCU_width_To_MCU_width = 1; 284 } else { 285 // Non-intervleaved 286 iMCU_width_To_MCU_width = cinfo->cur_comp_info[0]->h_samp_factor; 287 } 288 MCUs_per_row = jmin(MCUs_per_row, 289 (cinfo->coef->column_right_boundary - cinfo->coef->column_left_boundary) 290 * cinfo->entropy->index->MCU_sample_size * iMCU_width_To_MCU_width); 291 } 292 #endif 293 294 /* Loop to process one whole iMCU row */ 295 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 296 yoffset++) { 297 // configure huffman decoder 298 #ifdef ANDROID_TILE_BASED_DECODE 299 if (cinfo->tile_decode) { 300 huffman_scan_header scan_header = 301 cinfo->entropy->index->scan[cinfo->input_scan_number]; 302 int col_offset = cinfo->coef->column_left_boundary; 303 (*cinfo->entropy->configure_huffman_decoder) (cinfo, 304 scan_header.offset[cinfo->input_iMCU_row] 305 [col_offset + yoffset * scan_header.MCUs_per_row]); 306 } 307 #endif 308 309 // zero all blocks 310 for (MCU_col_num = coef->MCU_ctr; MCU_col_num < MCUs_per_row; 311 MCU_col_num++) { 312 /* Construct list of pointers to DCT blocks belonging to this MCU */ 313 blkn = 0; /* index of current DCT block within MCU */ 314 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 315 compptr = cinfo->cur_comp_info[ci]; 316 start_col = MCU_col_num * compptr->MCU_width; 317 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 318 buffer_ptr = buffer[ci][yindex+yoffset] + start_col; 319 for (xindex = 0; xindex < compptr->MCU_width; xindex++) { 320 coef->MCU_buffer[blkn++] = buffer_ptr++; 321 #ifdef ANDROID_TILE_BASED_DECODE 322 if (cinfo->tile_decode && cinfo->input_scan_number == 0) { 323 // need to do pre-zero ourselves. 324 jzero_far((void FAR *) coef->MCU_buffer[blkn-1], 325 (size_t) (SIZEOF(JBLOCK))); 326 } 327 #endif 328 } 329 } 330 } 331 332 333 /* Try to fetch the MCU. */ 334 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { 335 /* Suspension forced; update state counters and exit */ 336 coef->MCU_vert_offset = yoffset; 337 coef->MCU_ctr = MCU_col_num; 338 return JPEG_SUSPENDED; 339 } 340 } 341 /* Completed an MCU row, but perhaps not an iMCU row */ 342 coef->MCU_ctr = 0; 343 } 344 /* Completed the iMCU row, advance counters for next one */ 345 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { 346 start_iMCU_row(cinfo); 347 return JPEG_ROW_COMPLETED; 348 } 349 /* Completed the scan */ 350 (*cinfo->inputctl->finish_input_pass) (cinfo); 351 return JPEG_SCAN_COMPLETED; 352 } 353 354 /* 355 * Consume input data and store it in the coefficient buffer. 356 * Read one fully interleaved MCU row ("iMCU" row) per call. 357 */ 358 359 METHODDEF(int) 360 consume_data_multi_scan (j_decompress_ptr cinfo) 361 { 362 huffman_index *index = cinfo->entropy->index; 363 int i, retcode, ci; 364 int mcu = cinfo->input_iMCU_row; 365 jinit_phuff_decoder(cinfo); 366 for (i = 0; i < index->scan_count; i++) { 367 (*cinfo->inputctl->finish_input_pass) (cinfo); 368 jset_input_stream_position(cinfo, index->scan[i].bitstream_offset); 369 cinfo->output_iMCU_row = mcu; 370 cinfo->unread_marker = 0; 371 // Consume SOS and DHT headers 372 retcode = (*cinfo->inputctl->consume_markers) (cinfo, index, i); 373 cinfo->input_iMCU_row = mcu; 374 cinfo->input_scan_number = i; 375 cinfo->entropy->index = index; 376 // Consume scan block data 377 consume_data(cinfo); 378 } 379 cinfo->input_iMCU_row = mcu + 1; 380 cinfo->input_scan_number = 0; 381 cinfo->output_scan_number = 0; 382 return JPEG_ROW_COMPLETED; 383 } 384 385 /* 386 * Same as consume_data, expect for saving the Huffman decode information 387 * - bitstream offset and DC coefficient to index. 388 */ 389 390 METHODDEF(int) 391 consume_data_build_huffman_index_baseline (j_decompress_ptr cinfo, 392 huffman_index *index, int current_scan) 393 { 394 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 395 JDIMENSION MCU_col_num; /* index of current MCU within row */ 396 int ci, xindex, yindex, yoffset; 397 JDIMENSION start_col; 398 JBLOCKROW buffer_ptr; 399 400 huffman_scan_header *scan_header = index->scan + current_scan; 401 scan_header->MCU_rows_per_iMCU_row = coef->MCU_rows_per_iMCU_row; 402 403 size_t allocate_size = coef->MCU_rows_per_iMCU_row 404 * jdiv_round_up(cinfo->MCUs_per_row, index->MCU_sample_size) 405 * sizeof(huffman_offset_data); 406 scan_header->offset[cinfo->input_iMCU_row] = 407 (huffman_offset_data*)malloc(allocate_size); 408 index->mem_used += allocate_size; 409 410 huffman_offset_data *offset_data = scan_header->offset[cinfo->input_iMCU_row]; 411 412 /* Loop to process one whole iMCU row */ 413 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 414 yoffset++) { 415 for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row; 416 MCU_col_num++) { 417 // Record huffman bit offset 418 if (MCU_col_num % index->MCU_sample_size == 0) { 419 (*cinfo->entropy->get_huffman_decoder_configuration) 420 (cinfo, offset_data); 421 ++offset_data; 422 } 423 424 /* Try to fetch the MCU. */ 425 if (! (*cinfo->entropy->decode_mcu_discard_coef) (cinfo)) { 426 /* Suspension forced; update state counters and exit */ 427 coef->MCU_vert_offset = yoffset; 428 coef->MCU_ctr = MCU_col_num; 429 return JPEG_SUSPENDED; 430 } 431 } 432 /* Completed an MCU row, but perhaps not an iMCU row */ 433 coef->MCU_ctr = 0; 434 } 435 /* Completed the iMCU row, advance counters for next one */ 436 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { 437 start_iMCU_row(cinfo); 438 return JPEG_ROW_COMPLETED; 439 } 440 /* Completed the scan */ 441 (*cinfo->inputctl->finish_input_pass) (cinfo); 442 return JPEG_SCAN_COMPLETED; 443 } 444 445 /* 446 * Same as consume_data, expect for saving the Huffman decode information 447 * - bitstream offset and DC coefficient to index. 448 */ 449 450 METHODDEF(int) 451 consume_data_build_huffman_index_progressive (j_decompress_ptr cinfo, 452 huffman_index *index, int current_scan) 453 { 454 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 455 JDIMENSION MCU_col_num; /* index of current MCU within row */ 456 int blkn, ci, xindex, yindex, yoffset; 457 JDIMENSION start_col; 458 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; 459 JBLOCKROW buffer_ptr; 460 jpeg_component_info *compptr; 461 462 int factor = 4; // maximum factor is 4. 463 for (ci = 0; ci < cinfo->comps_in_scan; ci++) 464 factor = jmin(factor, cinfo->cur_comp_info[ci]->h_samp_factor); 465 466 int sample_size = index->MCU_sample_size * factor; 467 huffman_scan_header *scan_header = index->scan + current_scan; 468 scan_header->MCU_rows_per_iMCU_row = coef->MCU_rows_per_iMCU_row; 469 scan_header->MCUs_per_row = jdiv_round_up(cinfo->MCUs_per_row, sample_size); 470 scan_header->comps_in_scan = cinfo->comps_in_scan; 471 472 size_t allocate_size = coef->MCU_rows_per_iMCU_row 473 * scan_header->MCUs_per_row * sizeof(huffman_offset_data); 474 scan_header->offset[cinfo->input_iMCU_row] = 475 (huffman_offset_data*)malloc(allocate_size); 476 index->mem_used += allocate_size; 477 478 huffman_offset_data *offset_data = scan_header->offset[cinfo->input_iMCU_row]; 479 480 /* Align the virtual buffers for the components used in this scan. */ 481 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 482 compptr = cinfo->cur_comp_info[ci]; 483 buffer[ci] = (*cinfo->mem->access_virt_barray) 484 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], 485 0, // Only need one row buffer 486 (JDIMENSION) compptr->v_samp_factor, TRUE); 487 } 488 /* Loop to process one whole iMCU row */ 489 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; 490 yoffset++) { 491 for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row; 492 MCU_col_num++) { 493 /* For each MCU, we loop through different color components. 494 * Then, for each color component we will get a list of pointers to DCT 495 * blocks in the virtual buffer. 496 */ 497 blkn = 0; /* index of current DCT block within MCU */ 498 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 499 compptr = cinfo->cur_comp_info[ci]; 500 start_col = MCU_col_num * compptr->MCU_width; 501 /* Get the list of pointers to DCT blocks in 502 * the virtual buffer in a color component of the MCU. 503 */ 504 for (yindex = 0; yindex < compptr->MCU_height; yindex++) { 505 buffer_ptr = buffer[ci][yindex+yoffset] + start_col; 506 for (xindex = 0; xindex < compptr->MCU_width; xindex++) { 507 coef->MCU_buffer[blkn++] = buffer_ptr++; 508 if (cinfo->input_scan_number == 0) { 509 // need to do pre-zero by ourself. 510 jzero_far((void FAR *) coef->MCU_buffer[blkn-1], 511 (size_t) (SIZEOF(JBLOCK))); 512 } 513 } 514 } 515 } 516 // Record huffman bit offset 517 if (MCU_col_num % sample_size == 0) { 518 (*cinfo->entropy->get_huffman_decoder_configuration) 519 (cinfo, offset_data); 520 ++offset_data; 521 } 522 /* Try to fetch the MCU. */ 523 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { 524 /* Suspension forced; update state counters and exit */ 525 coef->MCU_vert_offset = yoffset; 526 coef->MCU_ctr = MCU_col_num; 527 return JPEG_SUSPENDED; 528 } 529 } 530 /* Completed an MCU row, but perhaps not an iMCU row */ 531 coef->MCU_ctr = 0; 532 } 533 (*cinfo->entropy->get_huffman_decoder_configuration) 534 (cinfo, &scan_header->prev_MCU_offset); 535 /* Completed the iMCU row, advance counters for next one */ 536 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { 537 start_iMCU_row(cinfo); 538 return JPEG_ROW_COMPLETED; 539 } 540 /* Completed the scan */ 541 (*cinfo->inputctl->finish_input_pass) (cinfo); 542 return JPEG_SCAN_COMPLETED; 543 } 544 545 /* 546 * Decompress and return some data in the multi-pass case. 547 * Always attempts to emit one fully interleaved MCU row ("iMCU" row). 548 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. 549 * 550 * NB: output_buf contains a plane for each component in image. 551 */ 552 553 METHODDEF(int) 554 decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) 555 { 556 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 557 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 558 JDIMENSION block_num; 559 int ci, block_row, block_rows; 560 JBLOCKARRAY buffer; 561 JBLOCKROW buffer_ptr; 562 JSAMPARRAY output_ptr; 563 JDIMENSION output_col; 564 jpeg_component_info *compptr; 565 inverse_DCT_method_ptr inverse_DCT; 566 567 /* Force some input to be done if we are getting ahead of the input. */ 568 while (cinfo->input_scan_number < cinfo->output_scan_number || 569 (cinfo->input_scan_number == cinfo->output_scan_number && 570 cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) { 571 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED) 572 return JPEG_SUSPENDED; 573 } 574 575 /* OK, output from the virtual arrays. */ 576 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 577 ci++, compptr++) { 578 /* Don't bother to IDCT an uninteresting component. */ 579 if (! compptr->component_needed) 580 continue; 581 /* Align the virtual buffer for this component. */ 582 buffer = (*cinfo->mem->access_virt_barray) 583 ((j_common_ptr) cinfo, coef->whole_image[ci], 584 cinfo->tile_decode ? 0 : cinfo->output_iMCU_row * compptr->v_samp_factor, 585 (JDIMENSION) compptr->v_samp_factor, FALSE); 586 /* Count non-dummy DCT block rows in this iMCU row. */ 587 if (cinfo->output_iMCU_row < last_iMCU_row) 588 block_rows = compptr->v_samp_factor; 589 else { 590 /* NB: can't use last_row_height here; it is input-side-dependent! */ 591 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 592 if (block_rows == 0) block_rows = compptr->v_samp_factor; 593 } 594 inverse_DCT = cinfo->idct->inverse_DCT[ci]; 595 output_ptr = output_buf[ci]; 596 int width_in_blocks = compptr->width_in_blocks; 597 int start_block = 0; 598 #if ANDROID_TILE_BASED_DECODE 599 if (cinfo->tile_decode) { 600 // width_in_blocks for a component depends on its h_samp_factor. 601 width_in_blocks = jmin(width_in_blocks, 602 (cinfo->coef->MCU_column_right_boundary - 603 cinfo->coef->MCU_column_left_boundary) * 604 compptr->h_samp_factor); 605 start_block = coef->pub.MCU_columns_to_skip * 606 compptr->h_samp_factor; 607 } 608 #endif 609 /* Loop over all DCT blocks to be processed. */ 610 for (block_row = 0; block_row < block_rows; block_row++) { 611 buffer_ptr = buffer[block_row]; 612 output_col = start_block * compptr->DCT_scaled_size; 613 buffer_ptr += start_block; 614 for (block_num = start_block; block_num < width_in_blocks; block_num++) { 615 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr, 616 output_ptr, output_col); 617 buffer_ptr++; 618 output_col += compptr->DCT_scaled_size; 619 } 620 output_ptr += compptr->DCT_scaled_size; 621 } 622 } 623 624 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows) 625 return JPEG_ROW_COMPLETED; 626 return JPEG_SCAN_COMPLETED; 627 } 628 629 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 630 631 632 #ifdef BLOCK_SMOOTHING_SUPPORTED 633 634 /* 635 * This code applies interblock smoothing as described by section K.8 636 * of the JPEG standard: the first 5 AC coefficients are estimated from 637 * the DC values of a DCT block and its 8 neighboring blocks. 638 * We apply smoothing only for progressive JPEG decoding, and only if 639 * the coefficients it can estimate are not yet known to full precision. 640 */ 641 642 /* Natural-order array positions of the first 5 zigzag-order coefficients */ 643 #define Q01_POS 1 644 #define Q10_POS 8 645 #define Q20_POS 16 646 #define Q11_POS 9 647 #define Q02_POS 2 648 649 /* 650 * Determine whether block smoothing is applicable and safe. 651 * We also latch the current states of the coef_bits[] entries for the 652 * AC coefficients; otherwise, if the input side of the decompressor 653 * advances into a new scan, we might think the coefficients are known 654 * more accurately than they really are. 655 */ 656 657 LOCAL(boolean) 658 smoothing_ok (j_decompress_ptr cinfo) 659 { 660 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 661 boolean smoothing_useful = FALSE; 662 int ci, coefi; 663 jpeg_component_info *compptr; 664 JQUANT_TBL * qtable; 665 int * coef_bits; 666 int * coef_bits_latch; 667 668 if (! cinfo->progressive_mode || cinfo->coef_bits == NULL) 669 return FALSE; 670 671 /* Allocate latch area if not already done */ 672 if (coef->coef_bits_latch == NULL) 673 coef->coef_bits_latch = (int *) 674 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 675 cinfo->num_components * 676 (SAVED_COEFS * SIZEOF(int))); 677 coef_bits_latch = coef->coef_bits_latch; 678 679 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 680 ci++, compptr++) { 681 /* All components' quantization values must already be latched. */ 682 if ((qtable = compptr->quant_table) == NULL) 683 return FALSE; 684 /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */ 685 if (qtable->quantval[0] == 0 || 686 qtable->quantval[Q01_POS] == 0 || 687 qtable->quantval[Q10_POS] == 0 || 688 qtable->quantval[Q20_POS] == 0 || 689 qtable->quantval[Q11_POS] == 0 || 690 qtable->quantval[Q02_POS] == 0) 691 return FALSE; 692 /* DC values must be at least partly known for all components. */ 693 coef_bits = cinfo->coef_bits[ci]; 694 if (coef_bits[0] < 0) 695 return FALSE; 696 /* Block smoothing is helpful if some AC coefficients remain inaccurate. */ 697 for (coefi = 1; coefi <= 5; coefi++) { 698 coef_bits_latch[coefi] = coef_bits[coefi]; 699 if (coef_bits[coefi] != 0) 700 smoothing_useful = TRUE; 701 } 702 coef_bits_latch += SAVED_COEFS; 703 } 704 705 return smoothing_useful; 706 } 707 708 709 /* 710 * Variant of decompress_data for use when doing block smoothing. 711 */ 712 713 METHODDEF(int) 714 decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) 715 { 716 my_coef_ptr coef = (my_coef_ptr) cinfo->coef; 717 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; 718 JDIMENSION block_num, last_block_column; 719 int ci, block_row, block_rows, access_rows; 720 JBLOCKARRAY buffer; 721 JBLOCKROW buffer_ptr, prev_block_row, next_block_row; 722 JSAMPARRAY output_ptr; 723 JDIMENSION output_col; 724 jpeg_component_info *compptr; 725 inverse_DCT_method_ptr inverse_DCT; 726 boolean first_row, last_row; 727 JBLOCK workspace; 728 int *coef_bits; 729 JQUANT_TBL *quanttbl; 730 INT32 Q00,Q01,Q02,Q10,Q11,Q20, num; 731 int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9; 732 int Al, pred; 733 734 /* Force some input to be done if we are getting ahead of the input. */ 735 while (cinfo->input_scan_number <= cinfo->output_scan_number && 736 ! cinfo->inputctl->eoi_reached) { 737 if (cinfo->input_scan_number == cinfo->output_scan_number) { 738 /* If input is working on current scan, we ordinarily want it to 739 * have completed the current row. But if input scan is DC, 740 * we want it to keep one row ahead so that next block row's DC 741 * values are up to date. 742 */ 743 JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0; 744 if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta) 745 break; 746 } 747 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED) 748 return JPEG_SUSPENDED; 749 } 750 751 /* OK, output from the virtual arrays. */ 752 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 753 ci++, compptr++) { 754 /* Don't bother to IDCT an uninteresting component. */ 755 if (! compptr->component_needed) 756 continue; 757 /* Count non-dummy DCT block rows in this iMCU row. */ 758 if (cinfo->output_iMCU_row < last_iMCU_row) { 759 block_rows = compptr->v_samp_factor; 760 access_rows = block_rows * 2; /* this and next iMCU row */ 761 last_row = FALSE; 762 } else { 763 /* NB: can't use last_row_height here; it is input-side-dependent! */ 764 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 765 if (block_rows == 0) block_rows = compptr->v_samp_factor; 766 access_rows = block_rows; /* this iMCU row only */ 767 last_row = TRUE; 768 } 769 /* Align the virtual buffer for this component. */ 770 if (cinfo->output_iMCU_row > 0) { 771 access_rows += compptr->v_samp_factor; /* prior iMCU row too */ 772 buffer = (*cinfo->mem->access_virt_barray) 773 ((j_common_ptr) cinfo, coef->whole_image[ci], 774 (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor, 775 (JDIMENSION) access_rows, FALSE); 776 buffer += compptr->v_samp_factor; /* point to current iMCU row */ 777 first_row = FALSE; 778 } else { 779 buffer = (*cinfo->mem->access_virt_barray) 780 ((j_common_ptr) cinfo, coef->whole_image[ci], 781 (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE); 782 first_row = TRUE; 783 } 784 /* Fetch component-dependent info */ 785 coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS); 786 quanttbl = compptr->quant_table; 787 Q00 = quanttbl->quantval[0]; 788 Q01 = quanttbl->quantval[Q01_POS]; 789 Q10 = quanttbl->quantval[Q10_POS]; 790 Q20 = quanttbl->quantval[Q20_POS]; 791 Q11 = quanttbl->quantval[Q11_POS]; 792 Q02 = quanttbl->quantval[Q02_POS]; 793 inverse_DCT = cinfo->idct->inverse_DCT[ci]; 794 output_ptr = output_buf[ci]; 795 /* Loop over all DCT blocks to be processed. */ 796 for (block_row = 0; block_row < block_rows; block_row++) { 797 buffer_ptr = buffer[block_row]; 798 if (first_row && block_row == 0) 799 prev_block_row = buffer_ptr; 800 else 801 prev_block_row = buffer[block_row-1]; 802 if (last_row && block_row == block_rows-1) 803 next_block_row = buffer_ptr; 804 else 805 next_block_row = buffer[block_row+1]; 806 /* We fetch the surrounding DC values using a sliding-register approach. 807 * Initialize all nine here so as to do the right thing on narrow pics. 808 */ 809 DC1 = DC2 = DC3 = (int) prev_block_row[0][0]; 810 DC4 = DC5 = DC6 = (int) buffer_ptr[0][0]; 811 DC7 = DC8 = DC9 = (int) next_block_row[0][0]; 812 output_col = 0; 813 last_block_column = compptr->width_in_blocks - 1; 814 for (block_num = 0; block_num <= last_block_column; block_num++) { 815 /* Fetch current DCT block into workspace so we can modify it. */ 816 jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1); 817 /* Update DC values */ 818 if (block_num < last_block_column) { 819 DC3 = (int) prev_block_row[1][0]; 820 DC6 = (int) buffer_ptr[1][0]; 821 DC9 = (int) next_block_row[1][0]; 822 } 823 /* Compute coefficient estimates per K.8. 824 * An estimate is applied only if coefficient is still zero, 825 * and is not known to be fully accurate. 826 */ 827 /* AC01 */ 828 if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) { 829 num = 36 * Q00 * (DC4 - DC6); 830 if (num >= 0) { 831 pred = (int) (((Q01<<7) + num) / (Q01<<8)); 832 if (Al > 0 && pred >= (1<<Al)) 833 pred = (1<<Al)-1; 834 } else { 835 pred = (int) (((Q01<<7) - num) / (Q01<<8)); 836 if (Al > 0 && pred >= (1<<Al)) 837 pred = (1<<Al)-1; 838 pred = -pred; 839 } 840 workspace[1] = (JCOEF) pred; 841 } 842 /* AC10 */ 843 if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) { 844 num = 36 * Q00 * (DC2 - DC8); 845 if (num >= 0) { 846 pred = (int) (((Q10<<7) + num) / (Q10<<8)); 847 if (Al > 0 && pred >= (1<<Al)) 848 pred = (1<<Al)-1; 849 } else { 850 pred = (int) (((Q10<<7) - num) / (Q10<<8)); 851 if (Al > 0 && pred >= (1<<Al)) 852 pred = (1<<Al)-1; 853 pred = -pred; 854 } 855 workspace[8] = (JCOEF) pred; 856 } 857 /* AC20 */ 858 if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) { 859 num = 9 * Q00 * (DC2 + DC8 - 2*DC5); 860 if (num >= 0) { 861 pred = (int) (((Q20<<7) + num) / (Q20<<8)); 862 if (Al > 0 && pred >= (1<<Al)) 863 pred = (1<<Al)-1; 864 } else { 865 pred = (int) (((Q20<<7) - num) / (Q20<<8)); 866 if (Al > 0 && pred >= (1<<Al)) 867 pred = (1<<Al)-1; 868 pred = -pred; 869 } 870 workspace[16] = (JCOEF) pred; 871 } 872 /* AC11 */ 873 if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) { 874 num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9); 875 if (num >= 0) { 876 pred = (int) (((Q11<<7) + num) / (Q11<<8)); 877 if (Al > 0 && pred >= (1<<Al)) 878 pred = (1<<Al)-1; 879 } else { 880 pred = (int) (((Q11<<7) - num) / (Q11<<8)); 881 if (Al > 0 && pred >= (1<<Al)) 882 pred = (1<<Al)-1; 883 pred = -pred; 884 } 885 workspace[9] = (JCOEF) pred; 886 } 887 /* AC02 */ 888 if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) { 889 num = 9 * Q00 * (DC4 + DC6 - 2*DC5); 890 if (num >= 0) { 891 pred = (int) (((Q02<<7) + num) / (Q02<<8)); 892 if (Al > 0 && pred >= (1<<Al)) 893 pred = (1<<Al)-1; 894 } else { 895 pred = (int) (((Q02<<7) - num) / (Q02<<8)); 896 if (Al > 0 && pred >= (1<<Al)) 897 pred = (1<<Al)-1; 898 pred = -pred; 899 } 900 workspace[2] = (JCOEF) pred; 901 } 902 /* OK, do the IDCT */ 903 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace, 904 output_ptr, output_col); 905 /* Advance for next column */ 906 DC1 = DC2; DC2 = DC3; 907 DC4 = DC5; DC5 = DC6; 908 DC7 = DC8; DC8 = DC9; 909 buffer_ptr++, prev_block_row++, next_block_row++; 910 output_col += compptr->DCT_scaled_size; 911 } 912 output_ptr += compptr->DCT_scaled_size; 913 } 914 } 915 916 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows) 917 return JPEG_ROW_COMPLETED; 918 return JPEG_SCAN_COMPLETED; 919 } 920 921 #endif /* BLOCK_SMOOTHING_SUPPORTED */ 922 923 924 /* 925 * Initialize coefficient buffer controller. 926 */ 927 928 GLOBAL(void) 929 jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer) 930 { 931 my_coef_ptr coef; 932 933 coef = (my_coef_ptr) 934 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 935 SIZEOF(my_coef_controller)); 936 cinfo->coef = (struct jpeg_d_coef_controller *) coef; 937 coef->pub.start_input_pass = start_input_pass; 938 coef->pub.start_output_pass = start_output_pass; 939 coef->pub.column_left_boundary = 0; 940 coef->pub.column_right_boundary = 0; 941 coef->pub.MCU_columns_to_skip = 0; 942 #ifdef BLOCK_SMOOTHING_SUPPORTED 943 coef->coef_bits_latch = NULL; 944 #endif 945 946 #ifdef ANDROID_TILE_BASED_DECODE 947 if (cinfo->tile_decode) { 948 if (cinfo->progressive_mode) { 949 /* Allocate one iMCU row virtual array, coef->whole_image[ci], 950 * for each color component, padded to a multiple of h_samp_factor 951 * DCT blocks in the horizontal direction. 952 */ 953 int ci, access_rows; 954 jpeg_component_info *compptr; 955 956 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 957 ci++, compptr++) { 958 access_rows = compptr->v_samp_factor; 959 coef->whole_image[ci] = (*cinfo->mem->request_virt_barray) 960 ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE, 961 (JDIMENSION) jround_up((long) compptr->width_in_blocks, 962 (long) compptr->h_samp_factor), 963 (JDIMENSION) compptr->v_samp_factor, // one iMCU row 964 (JDIMENSION) access_rows); 965 } 966 coef->pub.consume_data_build_huffman_index = 967 consume_data_build_huffman_index_progressive; 968 coef->pub.consume_data = consume_data_multi_scan; 969 coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */ 970 coef->pub.decompress_data = decompress_onepass; 971 } else { 972 /* We only need a single-MCU buffer. */ 973 JBLOCKROW buffer; 974 int i; 975 976 buffer = (JBLOCKROW) 977 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 978 D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 979 for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) { 980 coef->MCU_buffer[i] = buffer + i; 981 } 982 coef->pub.consume_data_build_huffman_index = 983 consume_data_build_huffman_index_baseline; 984 coef->pub.consume_data = dummy_consume_data; 985 coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */ 986 coef->pub.decompress_data = decompress_onepass; 987 } 988 return; 989 } 990 #endif 991 992 /* Create the coefficient buffer. */ 993 if (need_full_buffer) { 994 #ifdef D_MULTISCAN_FILES_SUPPORTED 995 /* Allocate a full-image virtual array for each component, */ 996 /* padded to a multiple of samp_factor DCT blocks in each direction. */ 997 /* Note we ask for a pre-zeroed array. */ 998 int ci, access_rows; 999 jpeg_component_info *compptr; 1000 1001 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 1002 ci++, compptr++) { 1003 access_rows = compptr->v_samp_factor; 1004 #ifdef BLOCK_SMOOTHING_SUPPORTED 1005 /* If block smoothing could be used, need a bigger window */ 1006 if (cinfo->progressive_mode) 1007 access_rows *= 3; 1008 #endif 1009 coef->whole_image[ci] = (*cinfo->mem->request_virt_barray) 1010 ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE, 1011 (JDIMENSION) jround_up((long) compptr->width_in_blocks, 1012 (long) compptr->h_samp_factor), 1013 (JDIMENSION) jround_up((long) compptr->height_in_blocks, 1014 (long) compptr->v_samp_factor), 1015 (JDIMENSION) access_rows); 1016 } 1017 coef->pub.consume_data = consume_data; 1018 coef->pub.decompress_data = decompress_data; 1019 coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */ 1020 #else 1021 ERREXIT(cinfo, JERR_NOT_COMPILED); 1022 #endif 1023 } else { 1024 /* We only need a single-MCU buffer. */ 1025 JBLOCKROW buffer; 1026 int i; 1027 1028 buffer = (JBLOCKROW) 1029 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 1030 D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); 1031 for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) { 1032 coef->MCU_buffer[i] = buffer + i; 1033 } 1034 coef->pub.consume_data = dummy_consume_data; 1035 coef->pub.decompress_data = decompress_onepass; 1036 coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */ 1037 } 1038 } 1039
