4
* Copyright (C) 1994-1997, Thomas G. Lane.
5
* Modified 2002-2011 by Guido Vollbeding.
6
* This file is part of the Independent JPEG Group's software.
7
* For conditions of distribution and use, see the accompanying README file.
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.
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.
18
#define JPEG_INTERNALS
22
/* Block smoothing is only applicable for progressive JPEG, so: */
23
#ifndef D_PROGRESSIVE_SUPPORTED
24
#undef BLOCK_SMOOTHING_SUPPORTED
27
/* Private buffer controller object */
30
struct jpeg_d_coef_controller pub; /* public fields */
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 */
38
/* The output side's location is represented by cinfo->output_iMCU_row. */
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.
49
JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
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];
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] */
63
typedef my_coef_controller * my_coef_ptr;
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));
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));
80
start_iMCU_row (j_decompress_ptr cinfo)
81
/* Reset within-iMCU-row counters for a new row (input side) */
83
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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.
89
if (cinfo->comps_in_scan > 1) {
90
coef->MCU_rows_per_iMCU_row = 1;
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;
95
coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
99
coef->MCU_vert_offset = 0;
104
* Initialize for an input processing pass.
108
start_input_pass (j_decompress_ptr cinfo)
110
cinfo->input_iMCU_row = 0;
111
start_iMCU_row(cinfo);
116
* Initialize for an output processing pass.
120
start_output_pass (j_decompress_ptr cinfo)
122
#ifdef BLOCK_SMOOTHING_SUPPORTED
123
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
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;
130
coef->pub.decompress_data = decompress_data;
133
cinfo->output_iMCU_row = 0;
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.
143
* NB: output_buf contains a plane for each component in image,
144
* which we index according to the component's SOF position.
148
decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
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;
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;
163
for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
165
/* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
166
if (cinfo->lim_Se) /* can bypass in DC only case */
167
FMEMZERO((void FAR *) coef->MCU_buffer[0],
168
(size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
169
if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
170
/* Suspension forced; update state counters and exit */
171
coef->MCU_vert_offset = yoffset;
172
coef->MCU_ctr = MCU_col_num;
173
return JPEG_SUSPENDED;
175
/* Determine where data should go in output_buf and do the IDCT thing.
176
* We skip dummy blocks at the right and bottom edges (but blkn gets
177
* incremented past them!). Note the inner loop relies on having
178
* allocated the MCU_buffer[] blocks sequentially.
180
blkn = 0; /* index of current DCT block within MCU */
181
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
182
compptr = cinfo->cur_comp_info[ci];
183
/* Don't bother to IDCT an uninteresting component. */
184
if (! compptr->component_needed) {
185
blkn += compptr->MCU_blocks;
188
inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
189
useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
190
: compptr->last_col_width;
191
output_ptr = output_buf[compptr->component_index] +
192
yoffset * compptr->DCT_v_scaled_size;
193
start_col = MCU_col_num * compptr->MCU_sample_width;
194
for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
195
if (cinfo->input_iMCU_row < last_iMCU_row ||
196
yoffset+yindex < compptr->last_row_height) {
197
output_col = start_col;
198
for (xindex = 0; xindex < useful_width; xindex++) {
199
(*inverse_DCT) (cinfo, compptr,
200
(JCOEFPTR) coef->MCU_buffer[blkn+xindex],
201
output_ptr, output_col);
202
output_col += compptr->DCT_h_scaled_size;
205
blkn += compptr->MCU_width;
206
output_ptr += compptr->DCT_v_scaled_size;
210
/* Completed an MCU row, but perhaps not an iMCU row */
213
/* Completed the iMCU row, advance counters for next one */
214
cinfo->output_iMCU_row++;
215
if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
216
start_iMCU_row(cinfo);
217
return JPEG_ROW_COMPLETED;
219
/* Completed the scan */
220
(*cinfo->inputctl->finish_input_pass) (cinfo);
221
return JPEG_SCAN_COMPLETED;
226
* Dummy consume-input routine for single-pass operation.
230
dummy_consume_data (j_decompress_ptr cinfo)
232
return JPEG_SUSPENDED; /* Always indicate nothing was done */
236
#ifdef D_MULTISCAN_FILES_SUPPORTED
239
* Consume input data and store it in the full-image coefficient buffer.
240
* We read as much as one fully interleaved MCU row ("iMCU" row) per call,
241
* ie, v_samp_factor block rows for each component in the scan.
242
* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
246
consume_data (j_decompress_ptr cinfo)
248
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
249
JDIMENSION MCU_col_num; /* index of current MCU within row */
250
int blkn, ci, xindex, yindex, yoffset;
251
JDIMENSION start_col;
252
JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
253
JBLOCKROW buffer_ptr;
254
jpeg_component_info *compptr;
256
/* Align the virtual buffers for the components used in this scan. */
257
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
258
compptr = cinfo->cur_comp_info[ci];
259
buffer[ci] = (*cinfo->mem->access_virt_barray)
260
((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
261
cinfo->input_iMCU_row * compptr->v_samp_factor,
262
(JDIMENSION) compptr->v_samp_factor, TRUE);
263
/* Note: entropy decoder expects buffer to be zeroed,
264
* but this is handled automatically by the memory manager
265
* because we requested a pre-zeroed array.
269
/* Loop to process one whole iMCU row */
270
for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
272
for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
274
/* Construct list of pointers to DCT blocks belonging to this MCU */
275
blkn = 0; /* index of current DCT block within MCU */
276
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
277
compptr = cinfo->cur_comp_info[ci];
278
start_col = MCU_col_num * compptr->MCU_width;
279
for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
280
buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
281
for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
282
coef->MCU_buffer[blkn++] = buffer_ptr++;
286
/* Try to fetch the MCU. */
287
if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
288
/* Suspension forced; update state counters and exit */
289
coef->MCU_vert_offset = yoffset;
290
coef->MCU_ctr = MCU_col_num;
291
return JPEG_SUSPENDED;
294
/* Completed an MCU row, but perhaps not an iMCU row */
297
/* Completed the iMCU row, advance counters for next one */
298
if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
299
start_iMCU_row(cinfo);
300
return JPEG_ROW_COMPLETED;
302
/* Completed the scan */
303
(*cinfo->inputctl->finish_input_pass) (cinfo);
304
return JPEG_SCAN_COMPLETED;
309
* Decompress and return some data in the multi-pass case.
310
* Always attempts to emit one fully interleaved MCU row ("iMCU" row).
311
* Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
313
* NB: output_buf contains a plane for each component in image.
317
decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
319
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
320
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
321
JDIMENSION block_num;
322
int ci, block_row, block_rows;
324
JBLOCKROW buffer_ptr;
325
JSAMPARRAY output_ptr;
326
JDIMENSION output_col;
327
jpeg_component_info *compptr;
328
inverse_DCT_method_ptr inverse_DCT;
330
/* Force some input to be done if we are getting ahead of the input. */
331
while (cinfo->input_scan_number < cinfo->output_scan_number ||
332
(cinfo->input_scan_number == cinfo->output_scan_number &&
333
cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
334
if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
335
return JPEG_SUSPENDED;
338
/* OK, output from the virtual arrays. */
339
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
341
/* Don't bother to IDCT an uninteresting component. */
342
if (! compptr->component_needed)
344
/* Align the virtual buffer for this component. */
345
buffer = (*cinfo->mem->access_virt_barray)
346
((j_common_ptr) cinfo, coef->whole_image[ci],
347
cinfo->output_iMCU_row * compptr->v_samp_factor,
348
(JDIMENSION) compptr->v_samp_factor, FALSE);
349
/* Count non-dummy DCT block rows in this iMCU row. */
350
if (cinfo->output_iMCU_row < last_iMCU_row)
351
block_rows = compptr->v_samp_factor;
353
/* NB: can't use last_row_height here; it is input-side-dependent! */
354
block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
355
if (block_rows == 0) block_rows = compptr->v_samp_factor;
357
inverse_DCT = cinfo->idct->inverse_DCT[ci];
358
output_ptr = output_buf[ci];
359
/* Loop over all DCT blocks to be processed. */
360
for (block_row = 0; block_row < block_rows; block_row++) {
361
buffer_ptr = buffer[block_row];
363
for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
364
(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
365
output_ptr, output_col);
367
output_col += compptr->DCT_h_scaled_size;
369
output_ptr += compptr->DCT_v_scaled_size;
373
if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
374
return JPEG_ROW_COMPLETED;
375
return JPEG_SCAN_COMPLETED;
378
#endif /* D_MULTISCAN_FILES_SUPPORTED */
381
#ifdef BLOCK_SMOOTHING_SUPPORTED
384
* This code applies interblock smoothing as described by section K.8
385
* of the JPEG standard: the first 5 AC coefficients are estimated from
386
* the DC values of a DCT block and its 8 neighboring blocks.
387
* We apply smoothing only for progressive JPEG decoding, and only if
388
* the coefficients it can estimate are not yet known to full precision.
391
/* Natural-order array positions of the first 5 zigzag-order coefficients */
399
* Determine whether block smoothing is applicable and safe.
400
* We also latch the current states of the coef_bits[] entries for the
401
* AC coefficients; otherwise, if the input side of the decompressor
402
* advances into a new scan, we might think the coefficients are known
403
* more accurately than they really are.
407
smoothing_ok (j_decompress_ptr cinfo)
409
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
410
boolean smoothing_useful = FALSE;
412
jpeg_component_info *compptr;
415
int * coef_bits_latch;
417
if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
420
/* Allocate latch area if not already done */
421
if (coef->coef_bits_latch == NULL)
422
coef->coef_bits_latch = (int *)
423
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
424
cinfo->num_components *
425
(SAVED_COEFS * SIZEOF(int)));
426
coef_bits_latch = coef->coef_bits_latch;
428
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
430
/* All components' quantization values must already be latched. */
431
if ((qtable = compptr->quant_table) == NULL)
433
/* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
434
if (qtable->quantval[0] == 0 ||
435
qtable->quantval[Q01_POS] == 0 ||
436
qtable->quantval[Q10_POS] == 0 ||
437
qtable->quantval[Q20_POS] == 0 ||
438
qtable->quantval[Q11_POS] == 0 ||
439
qtable->quantval[Q02_POS] == 0)
441
/* DC values must be at least partly known for all components. */
442
coef_bits = cinfo->coef_bits[ci];
443
if (coef_bits[0] < 0)
445
/* Block smoothing is helpful if some AC coefficients remain inaccurate. */
446
for (coefi = 1; coefi <= 5; coefi++) {
447
coef_bits_latch[coefi] = coef_bits[coefi];
448
if (coef_bits[coefi] != 0)
449
smoothing_useful = TRUE;
451
coef_bits_latch += SAVED_COEFS;
454
return smoothing_useful;
459
* Variant of decompress_data for use when doing block smoothing.
463
decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
465
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
466
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
467
JDIMENSION block_num, last_block_column;
468
int ci, block_row, block_rows, access_rows;
470
JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
471
JSAMPARRAY output_ptr;
472
JDIMENSION output_col;
473
jpeg_component_info *compptr;
474
inverse_DCT_method_ptr inverse_DCT;
475
boolean first_row, last_row;
478
JQUANT_TBL *quanttbl;
479
INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
480
int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
483
/* Force some input to be done if we are getting ahead of the input. */
484
while (cinfo->input_scan_number <= cinfo->output_scan_number &&
485
! cinfo->inputctl->eoi_reached) {
486
if (cinfo->input_scan_number == cinfo->output_scan_number) {
487
/* If input is working on current scan, we ordinarily want it to
488
* have completed the current row. But if input scan is DC,
489
* we want it to keep one row ahead so that next block row's DC
490
* values are up to date.
492
JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
493
if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
496
if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
497
return JPEG_SUSPENDED;
500
/* OK, output from the virtual arrays. */
501
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
503
/* Don't bother to IDCT an uninteresting component. */
504
if (! compptr->component_needed)
506
/* Count non-dummy DCT block rows in this iMCU row. */
507
if (cinfo->output_iMCU_row < last_iMCU_row) {
508
block_rows = compptr->v_samp_factor;
509
access_rows = block_rows * 2; /* this and next iMCU row */
512
/* NB: can't use last_row_height here; it is input-side-dependent! */
513
block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
514
if (block_rows == 0) block_rows = compptr->v_samp_factor;
515
access_rows = block_rows; /* this iMCU row only */
518
/* Align the virtual buffer for this component. */
519
if (cinfo->output_iMCU_row > 0) {
520
access_rows += compptr->v_samp_factor; /* prior iMCU row too */
521
buffer = (*cinfo->mem->access_virt_barray)
522
((j_common_ptr) cinfo, coef->whole_image[ci],
523
(cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
524
(JDIMENSION) access_rows, FALSE);
525
buffer += compptr->v_samp_factor; /* point to current iMCU row */
528
buffer = (*cinfo->mem->access_virt_barray)
529
((j_common_ptr) cinfo, coef->whole_image[ci],
530
(JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
533
/* Fetch component-dependent info */
534
coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
535
quanttbl = compptr->quant_table;
536
Q00 = quanttbl->quantval[0];
537
Q01 = quanttbl->quantval[Q01_POS];
538
Q10 = quanttbl->quantval[Q10_POS];
539
Q20 = quanttbl->quantval[Q20_POS];
540
Q11 = quanttbl->quantval[Q11_POS];
541
Q02 = quanttbl->quantval[Q02_POS];
542
inverse_DCT = cinfo->idct->inverse_DCT[ci];
543
output_ptr = output_buf[ci];
544
/* Loop over all DCT blocks to be processed. */
545
for (block_row = 0; block_row < block_rows; block_row++) {
546
buffer_ptr = buffer[block_row];
547
if (first_row && block_row == 0)
548
prev_block_row = buffer_ptr;
550
prev_block_row = buffer[block_row-1];
551
if (last_row && block_row == block_rows-1)
552
next_block_row = buffer_ptr;
554
next_block_row = buffer[block_row+1];
555
/* We fetch the surrounding DC values using a sliding-register approach.
556
* Initialize all nine here so as to do the right thing on narrow pics.
558
DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
559
DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
560
DC7 = DC8 = DC9 = (int) next_block_row[0][0];
562
last_block_column = compptr->width_in_blocks - 1;
563
for (block_num = 0; block_num <= last_block_column; block_num++) {
564
/* Fetch current DCT block into workspace so we can modify it. */
565
jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
566
/* Update DC values */
567
if (block_num < last_block_column) {
568
DC3 = (int) prev_block_row[1][0];
569
DC6 = (int) buffer_ptr[1][0];
570
DC9 = (int) next_block_row[1][0];
572
/* Compute coefficient estimates per K.8.
573
* An estimate is applied only if coefficient is still zero,
574
* and is not known to be fully accurate.
577
if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
578
num = 36 * Q00 * (DC4 - DC6);
580
pred = (int) (((Q01<<7) + num) / (Q01<<8));
581
if (Al > 0 && pred >= (1<<Al))
584
pred = (int) (((Q01<<7) - num) / (Q01<<8));
585
if (Al > 0 && pred >= (1<<Al))
589
workspace[1] = (JCOEF) pred;
592
if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
593
num = 36 * Q00 * (DC2 - DC8);
595
pred = (int) (((Q10<<7) + num) / (Q10<<8));
596
if (Al > 0 && pred >= (1<<Al))
599
pred = (int) (((Q10<<7) - num) / (Q10<<8));
600
if (Al > 0 && pred >= (1<<Al))
604
workspace[8] = (JCOEF) pred;
607
if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
608
num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
610
pred = (int) (((Q20<<7) + num) / (Q20<<8));
611
if (Al > 0 && pred >= (1<<Al))
614
pred = (int) (((Q20<<7) - num) / (Q20<<8));
615
if (Al > 0 && pred >= (1<<Al))
619
workspace[16] = (JCOEF) pred;
622
if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
623
num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
625
pred = (int) (((Q11<<7) + num) / (Q11<<8));
626
if (Al > 0 && pred >= (1<<Al))
629
pred = (int) (((Q11<<7) - num) / (Q11<<8));
630
if (Al > 0 && pred >= (1<<Al))
634
workspace[9] = (JCOEF) pred;
637
if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
638
num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
640
pred = (int) (((Q02<<7) + num) / (Q02<<8));
641
if (Al > 0 && pred >= (1<<Al))
644
pred = (int) (((Q02<<7) - num) / (Q02<<8));
645
if (Al > 0 && pred >= (1<<Al))
649
workspace[2] = (JCOEF) pred;
651
/* OK, do the IDCT */
652
(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
653
output_ptr, output_col);
654
/* Advance for next column */
655
DC1 = DC2; DC2 = DC3;
656
DC4 = DC5; DC5 = DC6;
657
DC7 = DC8; DC8 = DC9;
658
buffer_ptr++, prev_block_row++, next_block_row++;
659
output_col += compptr->DCT_h_scaled_size;
661
output_ptr += compptr->DCT_v_scaled_size;
665
if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
666
return JPEG_ROW_COMPLETED;
667
return JPEG_SCAN_COMPLETED;
670
#endif /* BLOCK_SMOOTHING_SUPPORTED */
674
* Initialize coefficient buffer controller.
678
jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
683
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
684
SIZEOF(my_coef_controller));
685
cinfo->coef = (struct jpeg_d_coef_controller *) coef;
686
coef->pub.start_input_pass = start_input_pass;
687
coef->pub.start_output_pass = start_output_pass;
688
#ifdef BLOCK_SMOOTHING_SUPPORTED
689
coef->coef_bits_latch = NULL;
692
/* Create the coefficient buffer. */
693
if (need_full_buffer) {
694
#ifdef D_MULTISCAN_FILES_SUPPORTED
695
/* Allocate a full-image virtual array for each component, */
696
/* padded to a multiple of samp_factor DCT blocks in each direction. */
697
/* Note we ask for a pre-zeroed array. */
699
jpeg_component_info *compptr;
701
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
703
access_rows = compptr->v_samp_factor;
704
#ifdef BLOCK_SMOOTHING_SUPPORTED
705
/* If block smoothing could be used, need a bigger window */
706
if (cinfo->progressive_mode)
709
coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
710
((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
711
(JDIMENSION) jround_up((long) compptr->width_in_blocks,
712
(long) compptr->h_samp_factor),
713
(JDIMENSION) jround_up((long) compptr->height_in_blocks,
714
(long) compptr->v_samp_factor),
715
(JDIMENSION) access_rows);
717
coef->pub.consume_data = consume_data;
718
coef->pub.decompress_data = decompress_data;
719
coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
721
ERREXIT(cinfo, JERR_NOT_COMPILED);
724
/* We only need a single-MCU buffer. */
729
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
730
D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
731
for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
732
coef->MCU_buffer[i] = buffer + i;
734
if (cinfo->lim_Se == 0) /* DC only case: want to bypass later */
735
FMEMZERO((void FAR *) buffer,
736
(size_t) (D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)));
737
coef->pub.consume_data = dummy_consume_data;
738
coef->pub.decompress_data = decompress_onepass;
739
coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
added
removed
jpg/jdcoefct.c
