4
* Copyright (C) 1994-1995, 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.
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.
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.
17
#define JPEG_INTERNALS
21
/* Block smoothing is only applicable for progressive JPEG, so: */
22
#ifndef D_PROGRESSIVE_SUPPORTED
23
#undef BLOCK_SMOOTHING_SUPPORTED
26
/* Private buffer controller object */
29
struct jpeg_d_coef_controller pub; /* public fields */
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 */
37
/* The output side's location is represented by cinfo->output_iMCU_row. */
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.
48
JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
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];
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] */
62
typedef my_coef_controller * my_coef_ptr;
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));
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));
79
start_iMCU_row (j_decompress_ptr cinfo)
80
/* Reset within-iMCU-row counters for a new row (input side) */
82
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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.
88
if (cinfo->comps_in_scan > 1) {
89
coef->MCU_rows_per_iMCU_row = 1;
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;
94
coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
98
coef->MCU_vert_offset = 0;
103
* Initialize for an input processing pass.
107
start_input_pass (j_decompress_ptr cinfo)
109
cinfo->input_iMCU_row = 0;
110
start_iMCU_row(cinfo);
115
* Initialize for an output processing pass.
119
start_output_pass (j_decompress_ptr cinfo)
121
#ifdef BLOCK_SMOOTHING_SUPPORTED
122
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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;
129
coef->pub.decompress_data = decompress_data;
132
cinfo->output_iMCU_row = 0;
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.
142
* NB: output_buf contains a plane for each component in image.
143
* For single pass, this is the same as the components in the scan.
147
decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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;
159
/* Loop to process as much as one whole iMCU row */
160
for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
162
for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
164
/* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
165
jzero_far((void FAR *) coef->MCU_buffer[0],
166
(size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
167
if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
168
/* Suspension forced; update state counters and exit */
169
coef->MCU_vert_offset = yoffset;
170
coef->MCU_ctr = MCU_col_num;
171
return JPEG_SUSPENDED;
173
/* Determine where data should go in output_buf and do the IDCT thing.
174
* We skip dummy blocks at the right and bottom edges (but blkn gets
175
* incremented past them!). Note the inner loop relies on having
176
* allocated the MCU_buffer[] blocks sequentially.
178
blkn = 0; /* index of current DCT block within MCU */
179
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
180
compptr = cinfo->cur_comp_info[ci];
181
/* Don't bother to IDCT an uninteresting component. */
182
if (! compptr->component_needed) {
183
blkn += compptr->MCU_blocks;
186
inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
187
useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
188
: compptr->last_col_width;
189
output_ptr = output_buf[ci] + yoffset * compptr->DCT_scaled_size;
190
start_col = MCU_col_num * compptr->MCU_sample_width;
191
for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
192
if (cinfo->input_iMCU_row < last_iMCU_row ||
193
yoffset+yindex < compptr->last_row_height) {
194
output_col = start_col;
195
for (xindex = 0; xindex < useful_width; xindex++) {
196
(*inverse_DCT) (cinfo, compptr,
197
(JCOEFPTR) coef->MCU_buffer[blkn+xindex],
198
output_ptr, output_col);
199
output_col += compptr->DCT_scaled_size;
202
blkn += compptr->MCU_width;
203
output_ptr += compptr->DCT_scaled_size;
207
/* Completed an MCU row, but perhaps not an iMCU row */
210
/* Completed the iMCU row, advance counters for next one */
211
cinfo->output_iMCU_row++;
212
if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
213
start_iMCU_row(cinfo);
214
return JPEG_ROW_COMPLETED;
216
/* Completed the scan */
217
(*cinfo->inputctl->finish_input_pass) (cinfo);
218
return JPEG_SCAN_COMPLETED;
223
* Dummy consume-input routine for single-pass operation.
227
dummy_consume_data (j_decompress_ptr cinfo)
229
return JPEG_SUSPENDED; /* Always indicate nothing was done */
233
#ifdef D_MULTISCAN_FILES_SUPPORTED
236
* Consume input data and store it in the full-image coefficient buffer.
237
* We read as much as one fully interleaved MCU row ("iMCU" row) per call,
238
* ie, v_samp_factor block rows for each component in the scan.
239
* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
243
consume_data (j_decompress_ptr cinfo)
245
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
246
JDIMENSION MCU_col_num; /* index of current MCU within row */
247
int blkn, ci, xindex, yindex, yoffset;
248
JDIMENSION start_col;
249
JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
250
JBLOCKROW buffer_ptr;
251
jpeg_component_info *compptr;
253
/* Align the virtual buffers for the components used in this scan. */
254
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
255
compptr = cinfo->cur_comp_info[ci];
256
buffer[ci] = (*cinfo->mem->access_virt_barray)
257
((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
258
cinfo->input_iMCU_row * compptr->v_samp_factor,
259
(JDIMENSION) compptr->v_samp_factor, TRUE);
260
/* Note: entropy decoder expects buffer to be zeroed,
261
* but this is handled automatically by the memory manager
262
* because we requested a pre-zeroed array.
266
/* Loop to process one whole iMCU row */
267
for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
269
for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
271
/* Construct list of pointers to DCT blocks belonging to this MCU */
272
blkn = 0; /* index of current DCT block within MCU */
273
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
274
compptr = cinfo->cur_comp_info[ci];
275
start_col = MCU_col_num * compptr->MCU_width;
276
for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
277
buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
278
for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
279
coef->MCU_buffer[blkn++] = buffer_ptr++;
283
/* Try to fetch the MCU. */
284
if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
285
/* Suspension forced; update state counters and exit */
286
coef->MCU_vert_offset = yoffset;
287
coef->MCU_ctr = MCU_col_num;
288
return JPEG_SUSPENDED;
291
/* Completed an MCU row, but perhaps not an iMCU row */
294
/* Completed the iMCU row, advance counters for next one */
295
if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
296
start_iMCU_row(cinfo);
297
return JPEG_ROW_COMPLETED;
299
/* Completed the scan */
300
(*cinfo->inputctl->finish_input_pass) (cinfo);
301
return JPEG_SCAN_COMPLETED;
306
* Decompress and return some data in the multi-pass case.
307
* Always attempts to emit one fully interleaved MCU row ("iMCU" row).
308
* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
310
* NB: output_buf contains a plane for each component in image.
314
decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
316
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
317
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
318
JDIMENSION block_num;
319
int ci, block_row, block_rows;
321
JBLOCKROW buffer_ptr;
322
JSAMPARRAY output_ptr;
323
JDIMENSION output_col;
324
jpeg_component_info *compptr;
325
inverse_DCT_method_ptr inverse_DCT;
327
/* Force some input to be done if we are getting ahead of the input. */
328
while (cinfo->input_scan_number < cinfo->output_scan_number ||
329
(cinfo->input_scan_number == cinfo->output_scan_number &&
330
cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
331
if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
332
return JPEG_SUSPENDED;
335
/* OK, output from the virtual arrays. */
336
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
338
/* Don't bother to IDCT an uninteresting component. */
339
if (! compptr->component_needed)
341
/* Align the virtual buffer for this component. */
342
buffer = (*cinfo->mem->access_virt_barray)
343
((j_common_ptr) cinfo, coef->whole_image[ci],
344
cinfo->output_iMCU_row * compptr->v_samp_factor,
345
(JDIMENSION) compptr->v_samp_factor, FALSE);
346
/* Count non-dummy DCT block rows in this iMCU row. */
347
if (cinfo->output_iMCU_row < last_iMCU_row)
348
block_rows = compptr->v_samp_factor;
350
/* NB: can't use last_row_height here; it is input-side-dependent! */
351
block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
352
if (block_rows == 0) block_rows = compptr->v_samp_factor;
354
inverse_DCT = cinfo->idct->inverse_DCT[ci];
355
output_ptr = output_buf[ci];
356
/* Loop over all DCT blocks to be processed. */
357
for (block_row = 0; block_row < block_rows; block_row++) {
358
buffer_ptr = buffer[block_row];
360
for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
361
(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
362
output_ptr, output_col);
364
output_col += compptr->DCT_scaled_size;
366
output_ptr += compptr->DCT_scaled_size;
370
if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
371
return JPEG_ROW_COMPLETED;
372
return JPEG_SCAN_COMPLETED;
375
#endif /* D_MULTISCAN_FILES_SUPPORTED */
378
#ifdef BLOCK_SMOOTHING_SUPPORTED
381
* This code applies interblock smoothing as described by section K.8
382
* of the JPEG standard: the first 5 AC coefficients are estimated from
383
* the DC values of a DCT block and its 8 neighboring blocks.
384
* We apply smoothing only for progressive JPEG decoding, and only if
385
* the coefficients it can estimate are not yet known to full precision.
389
* Determine whether block smoothing is applicable and safe.
390
* We also latch the current states of the coef_bits[] entries for the
391
* AC coefficients; otherwise, if the input side of the decompressor
392
* advances into a new scan, we might think the coefficients are known
393
* more accurately than they really are.
397
smoothing_ok (j_decompress_ptr cinfo)
399
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
400
boolean smoothing_useful = FALSE;
402
jpeg_component_info *compptr;
405
int * coef_bits_latch;
407
if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
410
/* Allocate latch area if not already done */
411
if (coef->coef_bits_latch == NULL)
412
coef->coef_bits_latch = (int *)
413
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
414
cinfo->num_components *
415
(SAVED_COEFS * SIZEOF(int)));
416
coef_bits_latch = coef->coef_bits_latch;
418
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
420
/* All components' quantization values must already be latched. */
421
if ((qtable = compptr->quant_table) == NULL)
423
/* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
424
for (coefi = 0; coefi <= 5; coefi++) {
425
if (qtable->quantval[coefi] == 0)
428
/* DC values must be at least partly known for all components. */
429
coef_bits = cinfo->coef_bits[ci];
430
if (coef_bits[0] < 0)
432
/* Block smoothing is helpful if some AC coefficients remain inaccurate. */
433
for (coefi = 1; coefi <= 5; coefi++) {
434
coef_bits_latch[coefi] = coef_bits[coefi];
435
if (coef_bits[coefi] != 0)
436
smoothing_useful = TRUE;
438
coef_bits_latch += SAVED_COEFS;
441
return smoothing_useful;
446
* Variant of decompress_data for use when doing block smoothing.
450
decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
452
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
453
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
454
JDIMENSION block_num, last_block_column;
455
int ci, block_row, block_rows, access_rows;
457
JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
458
JSAMPARRAY output_ptr;
459
JDIMENSION output_col;
460
jpeg_component_info *compptr;
461
inverse_DCT_method_ptr inverse_DCT;
462
boolean first_row, last_row;
465
JQUANT_TBL *quanttbl;
466
INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
467
int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
470
/* Force some input to be done if we are getting ahead of the input. */
471
while (cinfo->input_scan_number <= cinfo->output_scan_number &&
472
! cinfo->inputctl->eoi_reached) {
473
if (cinfo->input_scan_number == cinfo->output_scan_number) {
474
/* If input is working on current scan, we ordinarily want it to
475
* have completed the current row. But if input scan is DC,
476
* we want it to keep one row ahead so that next block row's DC
477
* values are up to date.
479
JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
480
if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
483
if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
484
return JPEG_SUSPENDED;
487
/* OK, output from the virtual arrays. */
488
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
490
/* Don't bother to IDCT an uninteresting component. */
491
if (! compptr->component_needed)
493
/* Count non-dummy DCT block rows in this iMCU row. */
494
if (cinfo->output_iMCU_row < last_iMCU_row) {
495
block_rows = compptr->v_samp_factor;
496
access_rows = block_rows * 2; /* this and next iMCU row */
499
/* NB: can't use last_row_height here; it is input-side-dependent! */
500
block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
501
if (block_rows == 0) block_rows = compptr->v_samp_factor;
502
access_rows = block_rows; /* this iMCU row only */
505
/* Align the virtual buffer for this component. */
506
if (cinfo->output_iMCU_row > 0) {
507
access_rows += compptr->v_samp_factor; /* prior iMCU row too */
508
buffer = (*cinfo->mem->access_virt_barray)
509
((j_common_ptr) cinfo, coef->whole_image[ci],
510
(cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
511
(JDIMENSION) access_rows, FALSE);
512
buffer += compptr->v_samp_factor; /* point to current iMCU row */
515
buffer = (*cinfo->mem->access_virt_barray)
516
((j_common_ptr) cinfo, coef->whole_image[ci],
517
(JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
520
/* Fetch component-dependent info */
521
coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
522
quanttbl = compptr->quant_table;
523
Q00 = quanttbl->quantval[0];
524
Q01 = quanttbl->quantval[1];
525
Q10 = quanttbl->quantval[2];
526
Q20 = quanttbl->quantval[3];
527
Q11 = quanttbl->quantval[4];
528
Q02 = quanttbl->quantval[5];
529
inverse_DCT = cinfo->idct->inverse_DCT[ci];
530
output_ptr = output_buf[ci];
531
/* Loop over all DCT blocks to be processed. */
532
for (block_row = 0; block_row < block_rows; block_row++) {
533
buffer_ptr = buffer[block_row];
534
if (first_row && block_row == 0)
535
prev_block_row = buffer_ptr;
537
prev_block_row = buffer[block_row-1];
538
if (last_row && block_row == block_rows-1)
539
next_block_row = buffer_ptr;
541
next_block_row = buffer[block_row+1];
542
/* We fetch the surrounding DC values using a sliding-register approach.
543
* Initialize all nine here so as to do the right thing on narrow pics.
545
DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
546
DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
547
DC7 = DC8 = DC9 = (int) next_block_row[0][0];
549
last_block_column = compptr->width_in_blocks - 1;
550
for (block_num = 0; block_num <= last_block_column; block_num++) {
551
/* Fetch current DCT block into workspace so we can modify it. */
552
jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
553
/* Update DC values */
554
if (block_num < last_block_column) {
555
DC3 = (int) prev_block_row[1][0];
556
DC6 = (int) buffer_ptr[1][0];
557
DC9 = (int) next_block_row[1][0];
559
/* Compute coefficient estimates per K.8.
560
* An estimate is applied only if coefficient is still zero,
561
* and is not known to be fully accurate.
564
if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
565
num = 36 * Q00 * (DC4 - DC6);
567
pred = (int) (((Q01<<7) + num) / (Q01<<8));
568
if (Al > 0 && pred >= (1<<Al))
571
pred = (int) (((Q01<<7) - num) / (Q01<<8));
572
if (Al > 0 && pred >= (1<<Al))
576
workspace[1] = (JCOEF) pred;
579
if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
580
num = 36 * Q00 * (DC2 - DC8);
582
pred = (int) (((Q10<<7) + num) / (Q10<<8));
583
if (Al > 0 && pred >= (1<<Al))
586
pred = (int) (((Q10<<7) - num) / (Q10<<8));
587
if (Al > 0 && pred >= (1<<Al))
591
workspace[8] = (JCOEF) pred;
594
if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
595
num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
597
pred = (int) (((Q20<<7) + num) / (Q20<<8));
598
if (Al > 0 && pred >= (1<<Al))
601
pred = (int) (((Q20<<7) - num) / (Q20<<8));
602
if (Al > 0 && pred >= (1<<Al))
606
workspace[16] = (JCOEF) pred;
609
if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
610
num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
612
pred = (int) (((Q11<<7) + num) / (Q11<<8));
613
if (Al > 0 && pred >= (1<<Al))
616
pred = (int) (((Q11<<7) - num) / (Q11<<8));
617
if (Al > 0 && pred >= (1<<Al))
621
workspace[9] = (JCOEF) pred;
624
if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
625
num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
627
pred = (int) (((Q02<<7) + num) / (Q02<<8));
628
if (Al > 0 && pred >= (1<<Al))
631
pred = (int) (((Q02<<7) - num) / (Q02<<8));
632
if (Al > 0 && pred >= (1<<Al))
636
workspace[2] = (JCOEF) pred;
638
/* OK, do the IDCT */
639
(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
640
output_ptr, output_col);
641
/* Advance for next column */
642
DC1 = DC2; DC2 = DC3;
643
DC4 = DC5; DC5 = DC6;
644
DC7 = DC8; DC8 = DC9;
645
buffer_ptr++, prev_block_row++, next_block_row++;
646
output_col += compptr->DCT_scaled_size;
648
output_ptr += compptr->DCT_scaled_size;
652
if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
653
return JPEG_ROW_COMPLETED;
654
return JPEG_SCAN_COMPLETED;
657
#endif /* BLOCK_SMOOTHING_SUPPORTED */
661
* Initialize coefficient buffer controller.
665
jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
670
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
671
SIZEOF(my_coef_controller));
672
cinfo->coef = (struct jpeg_d_coef_controller *) coef;
673
coef->pub.start_input_pass = start_input_pass;
674
coef->pub.start_output_pass = start_output_pass;
675
#ifdef BLOCK_SMOOTHING_SUPPORTED
676
coef->coef_bits_latch = NULL;
679
/* Create the coefficient buffer. */
680
if (need_full_buffer) {
681
#ifdef D_MULTISCAN_FILES_SUPPORTED
682
/* Allocate a full-image virtual array for each component, */
683
/* padded to a multiple of samp_factor DCT blocks in each direction. */
684
/* Note we ask for a pre-zeroed array. */
686
jpeg_component_info *compptr;
688
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
690
access_rows = compptr->v_samp_factor;
691
#ifdef BLOCK_SMOOTHING_SUPPORTED
692
/* If block smoothing could be used, need a bigger window */
693
if (cinfo->progressive_mode)
696
coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
697
((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
698
(JDIMENSION) jround_up((long) compptr->width_in_blocks,
699
(long) compptr->h_samp_factor),
700
(JDIMENSION) jround_up((long) compptr->height_in_blocks,
701
(long) compptr->v_samp_factor),
702
(JDIMENSION) access_rows);
704
coef->pub.consume_data = consume_data;
705
coef->pub.decompress_data = decompress_data;
706
coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
708
ERREXIT(cinfo, JERR_NOT_COMPILED);
711
/* We only need a single-MCU buffer. */
716
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
717
D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
718
for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
719
coef->MCU_buffer[i] = buffer + i;
721
coef->pub.consume_data = dummy_consume_data;
722
coef->pub.decompress_data = decompress_onepass;
723
coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
added
removed
code/jpeg-6/jdcoefct.c
