Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(91)

Side by Side Diff: third_party/libjpeg_turbo/jdcoefct.c

Issue 4134011: Adds libjpeg-turbo to deps... (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/deps/
Patch Set: Created 10 years, 1 month ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch | Annotate | Revision Log
« no previous file with comments | « third_party/libjpeg_turbo/jdatasrc.c ('k') | third_party/libjpeg_turbo/jdcolor.c » ('j') | no next file with comments »
Toggle Intra-line Diffs ('i') | Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
OLDNEW
(Empty)
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 /* Temporary workspace for one MCU */
51 JCOEF * workspace;
52
53 #ifdef D_MULTISCAN_FILES_SUPPORTED
54 /* In multi-pass modes, we need a virtual block array for each component. */
55 jvirt_barray_ptr whole_image[MAX_COMPONENTS];
56 #endif
57
58 #ifdef BLOCK_SMOOTHING_SUPPORTED
59 /* When doing block smoothing, we latch coefficient Al values here */
60 int * coef_bits_latch;
61 #define SAVED_COEFS 6 /* we save coef_bits[0..5] */
62 #endif
63 } my_coef_controller;
64
65 typedef my_coef_controller * my_coef_ptr;
66
67 /* Forward declarations */
68 METHODDEF(int) decompress_onepass
69 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
70 #ifdef D_MULTISCAN_FILES_SUPPORTED
71 METHODDEF(int) decompress_data
72 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
73 #endif
74 #ifdef BLOCK_SMOOTHING_SUPPORTED
75 LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo));
76 METHODDEF(int) decompress_smooth_data
77 JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
78 #endif
79
80
81 LOCAL(void)
82 start_iMCU_row (j_decompress_ptr cinfo)
83 /* Reset within-iMCU-row counters for a new row (input side) */
84 {
85 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
86
87 /* In an interleaved scan, an MCU row is the same as an iMCU row.
88 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
89 * But at the bottom of the image, process only what's left.
90 */
91 if (cinfo->comps_in_scan > 1) {
92 coef->MCU_rows_per_iMCU_row = 1;
93 } else {
94 if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
95 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
96 else
97 coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
98 }
99
100 coef->MCU_ctr = 0;
101 coef->MCU_vert_offset = 0;
102 }
103
104
105 /*
106 * Initialize for an input processing pass.
107 */
108
109 METHODDEF(void)
110 start_input_pass (j_decompress_ptr cinfo)
111 {
112 cinfo->input_iMCU_row = 0;
113 start_iMCU_row(cinfo);
114 }
115
116
117 /*
118 * Initialize for an output processing pass.
119 */
120
121 METHODDEF(void)
122 start_output_pass (j_decompress_ptr cinfo)
123 {
124 #ifdef BLOCK_SMOOTHING_SUPPORTED
125 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
126
127 /* If multipass, check to see whether to use block smoothing on this pass */
128 if (coef->pub.coef_arrays != NULL) {
129 if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
130 coef->pub.decompress_data = decompress_smooth_data;
131 else
132 coef->pub.decompress_data = decompress_data;
133 }
134 #endif
135 cinfo->output_iMCU_row = 0;
136 }
137
138
139 /*
140 * Decompress and return some data in the single-pass case.
141 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
142 * Input and output must run in lockstep since we have only a one-MCU buffer.
143 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
144 *
145 * NB: output_buf contains a plane for each component in image,
146 * which we index according to the component's SOF position.
147 */
148
149 METHODDEF(int)
150 decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
151 {
152 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
153 JDIMENSION MCU_col_num; /* index of current MCU within row */
154 JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
155 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
156 int blkn, ci, xindex, yindex, yoffset, useful_width;
157 JSAMPARRAY output_ptr;
158 JDIMENSION start_col, output_col;
159 jpeg_component_info *compptr;
160 inverse_DCT_method_ptr inverse_DCT;
161
162 /* Loop to process as much as one whole iMCU row */
163 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
164 yoffset++) {
165 for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
166 MCU_col_num++) {
167 /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
168 jzero_far((void FAR *) coef->MCU_buffer[0],
169 (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
170 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
171 /* Suspension forced; update state counters and exit */
172 coef->MCU_vert_offset = yoffset;
173 coef->MCU_ctr = MCU_col_num;
174 return JPEG_SUSPENDED;
175 }
176 /* Determine where data should go in output_buf and do the IDCT thing.
177 * We skip dummy blocks at the right and bottom edges (but blkn gets
178 * incremented past them!). Note the inner loop relies on having
179 * allocated the MCU_buffer[] blocks sequentially.
180 */
181 blkn = 0; /* index of current DCT block within MCU */
182 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
183 compptr = cinfo->cur_comp_info[ci];
184 /* Don't bother to IDCT an uninteresting component. */
185 if (! compptr->component_needed) {
186 blkn += compptr->MCU_blocks;
187 continue;
188 }
189 inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
190 useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
191 : compptr->last_col_width;
192 output_ptr = output_buf[compptr->component_index] +
193 yoffset * compptr->DCT_scaled_size;
194 start_col = MCU_col_num * compptr->MCU_sample_width;
195 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
196 if (cinfo->input_iMCU_row < last_iMCU_row ||
197 yoffset+yindex < compptr->last_row_height) {
198 output_col = start_col;
199 for (xindex = 0; xindex < useful_width; xindex++) {
200 (*inverse_DCT) (cinfo, compptr,
201 (JCOEFPTR) coef->MCU_buffer[blkn+xindex],
202 output_ptr, output_col);
203 output_col += compptr->DCT_scaled_size;
204 }
205 }
206 blkn += compptr->MCU_width;
207 output_ptr += compptr->DCT_scaled_size;
208 }
209 }
210 }
211 /* Completed an MCU row, but perhaps not an iMCU row */
212 coef->MCU_ctr = 0;
213 }
214 /* Completed the iMCU row, advance counters for next one */
215 cinfo->output_iMCU_row++;
216 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
217 start_iMCU_row(cinfo);
218 return JPEG_ROW_COMPLETED;
219 }
220 /* Completed the scan */
221 (*cinfo->inputctl->finish_input_pass) (cinfo);
222 return JPEG_SCAN_COMPLETED;
223 }
224
225
226 /*
227 * Dummy consume-input routine for single-pass operation.
228 */
229
230 METHODDEF(int)
231 dummy_consume_data (j_decompress_ptr cinfo)
232 {
233 return JPEG_SUSPENDED; /* Always indicate nothing was done */
234 }
235
236
237 #ifdef D_MULTISCAN_FILES_SUPPORTED
238
239 /*
240 * Consume input data and store it in the full-image coefficient buffer.
241 * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
242 * ie, v_samp_factor block rows for each component in the scan.
243 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
244 */
245
246 METHODDEF(int)
247 consume_data (j_decompress_ptr cinfo)
248 {
249 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
250 JDIMENSION MCU_col_num; /* index of current MCU within row */
251 int blkn, ci, xindex, yindex, yoffset;
252 JDIMENSION start_col;
253 JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
254 JBLOCKROW buffer_ptr;
255 jpeg_component_info *compptr;
256
257 /* Align the virtual buffers for the components used in this scan. */
258 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
259 compptr = cinfo->cur_comp_info[ci];
260 buffer[ci] = (*cinfo->mem->access_virt_barray)
261 ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
262 cinfo->input_iMCU_row * compptr->v_samp_factor,
263 (JDIMENSION) compptr->v_samp_factor, TRUE);
264 /* Note: entropy decoder expects buffer to be zeroed,
265 * but this is handled automatically by the memory manager
266 * because we requested a pre-zeroed array.
267 */
268 }
269
270 /* Loop to process one whole iMCU row */
271 for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
272 yoffset++) {
273 for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
274 MCU_col_num++) {
275 /* Construct list of pointers to DCT blocks belonging to this MCU */
276 blkn = 0; /* index of current DCT block within MCU */
277 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
278 compptr = cinfo->cur_comp_info[ci];
279 start_col = MCU_col_num * compptr->MCU_width;
280 for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
281 buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
282 for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
283 coef->MCU_buffer[blkn++] = buffer_ptr++;
284 }
285 }
286 }
287 /* Try to fetch the MCU. */
288 if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
289 /* Suspension forced; update state counters and exit */
290 coef->MCU_vert_offset = yoffset;
291 coef->MCU_ctr = MCU_col_num;
292 return JPEG_SUSPENDED;
293 }
294 }
295 /* Completed an MCU row, but perhaps not an iMCU row */
296 coef->MCU_ctr = 0;
297 }
298 /* Completed the iMCU row, advance counters for next one */
299 if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
300 start_iMCU_row(cinfo);
301 return JPEG_ROW_COMPLETED;
302 }
303 /* Completed the scan */
304 (*cinfo->inputctl->finish_input_pass) (cinfo);
305 return JPEG_SCAN_COMPLETED;
306 }
307
308
309 /*
310 * Decompress and return some data in the multi-pass case.
311 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
312 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
313 *
314 * NB: output_buf contains a plane for each component in image.
315 */
316
317 METHODDEF(int)
318 decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
319 {
320 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
321 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
322 JDIMENSION block_num;
323 int ci, block_row, block_rows;
324 JBLOCKARRAY buffer;
325 JBLOCKROW buffer_ptr;
326 JSAMPARRAY output_ptr;
327 JDIMENSION output_col;
328 jpeg_component_info *compptr;
329 inverse_DCT_method_ptr inverse_DCT;
330
331 /* Force some input to be done if we are getting ahead of the input. */
332 while (cinfo->input_scan_number < cinfo->output_scan_number ||
333 (cinfo->input_scan_number == cinfo->output_scan_number &&
334 cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
335 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
336 return JPEG_SUSPENDED;
337 }
338
339 /* OK, output from the virtual arrays. */
340 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
341 ci++, compptr++) {
342 /* Don't bother to IDCT an uninteresting component. */
343 if (! compptr->component_needed)
344 continue;
345 /* Align the virtual buffer for this component. */
346 buffer = (*cinfo->mem->access_virt_barray)
347 ((j_common_ptr) cinfo, coef->whole_image[ci],
348 cinfo->output_iMCU_row * compptr->v_samp_factor,
349 (JDIMENSION) compptr->v_samp_factor, FALSE);
350 /* Count non-dummy DCT block rows in this iMCU row. */
351 if (cinfo->output_iMCU_row < last_iMCU_row)
352 block_rows = compptr->v_samp_factor;
353 else {
354 /* NB: can't use last_row_height here; it is input-side-dependent! */
355 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
356 if (block_rows == 0) block_rows = compptr->v_samp_factor;
357 }
358 inverse_DCT = cinfo->idct->inverse_DCT[ci];
359 output_ptr = output_buf[ci];
360 /* Loop over all DCT blocks to be processed. */
361 for (block_row = 0; block_row < block_rows; block_row++) {
362 buffer_ptr = buffer[block_row];
363 output_col = 0;
364 for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
365 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
366 output_ptr, output_col);
367 buffer_ptr++;
368 output_col += compptr->DCT_scaled_size;
369 }
370 output_ptr += compptr->DCT_scaled_size;
371 }
372 }
373
374 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
375 return JPEG_ROW_COMPLETED;
376 return JPEG_SCAN_COMPLETED;
377 }
378
379 #endif /* D_MULTISCAN_FILES_SUPPORTED */
380
381
382 #ifdef BLOCK_SMOOTHING_SUPPORTED
383
384 /*
385 * This code applies interblock smoothing as described by section K.8
386 * of the JPEG standard: the first 5 AC coefficients are estimated from
387 * the DC values of a DCT block and its 8 neighboring blocks.
388 * We apply smoothing only for progressive JPEG decoding, and only if
389 * the coefficients it can estimate are not yet known to full precision.
390 */
391
392 /* Natural-order array positions of the first 5 zigzag-order coefficients */
393 #define Q01_POS 1
394 #define Q10_POS 8
395 #define Q20_POS 16
396 #define Q11_POS 9
397 #define Q02_POS 2
398
399 /*
400 * Determine whether block smoothing is applicable and safe.
401 * We also latch the current states of the coef_bits[] entries for the
402 * AC coefficients; otherwise, if the input side of the decompressor
403 * advances into a new scan, we might think the coefficients are known
404 * more accurately than they really are.
405 */
406
407 LOCAL(boolean)
408 smoothing_ok (j_decompress_ptr cinfo)
409 {
410 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
411 boolean smoothing_useful = FALSE;
412 int ci, coefi;
413 jpeg_component_info *compptr;
414 JQUANT_TBL * qtable;
415 int * coef_bits;
416 int * coef_bits_latch;
417
418 if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
419 return FALSE;
420
421 /* Allocate latch area if not already done */
422 if (coef->coef_bits_latch == NULL)
423 coef->coef_bits_latch = (int *)
424 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
425 cinfo->num_components *
426 (SAVED_COEFS * SIZEOF(int)));
427 coef_bits_latch = coef->coef_bits_latch;
428
429 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
430 ci++, compptr++) {
431 /* All components' quantization values must already be latched. */
432 if ((qtable = compptr->quant_table) == NULL)
433 return FALSE;
434 /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
435 if (qtable->quantval[0] == 0 ||
436 qtable->quantval[Q01_POS] == 0 ||
437 qtable->quantval[Q10_POS] == 0 ||
438 qtable->quantval[Q20_POS] == 0 ||
439 qtable->quantval[Q11_POS] == 0 ||
440 qtable->quantval[Q02_POS] == 0)
441 return FALSE;
442 /* DC values must be at least partly known for all components. */
443 coef_bits = cinfo->coef_bits[ci];
444 if (coef_bits[0] < 0)
445 return FALSE;
446 /* Block smoothing is helpful if some AC coefficients remain inaccurate. */
447 for (coefi = 1; coefi <= 5; coefi++) {
448 coef_bits_latch[coefi] = coef_bits[coefi];
449 if (coef_bits[coefi] != 0)
450 smoothing_useful = TRUE;
451 }
452 coef_bits_latch += SAVED_COEFS;
453 }
454
455 return smoothing_useful;
456 }
457
458
459 /*
460 * Variant of decompress_data for use when doing block smoothing.
461 */
462
463 METHODDEF(int)
464 decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
465 {
466 my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
467 JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
468 JDIMENSION block_num, last_block_column;
469 int ci, block_row, block_rows, access_rows;
470 JBLOCKARRAY buffer;
471 JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
472 JSAMPARRAY output_ptr;
473 JDIMENSION output_col;
474 jpeg_component_info *compptr;
475 inverse_DCT_method_ptr inverse_DCT;
476 boolean first_row, last_row;
477 JCOEF * workspace;
478 int *coef_bits;
479 JQUANT_TBL *quanttbl;
480 INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
481 int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
482 int Al, pred;
483
484 /* Keep a local variable to avoid looking it up more than once */
485 workspace = coef->workspace;
486
487 /* Force some input to be done if we are getting ahead of the input. */
488 while (cinfo->input_scan_number <= cinfo->output_scan_number &&
489 ! cinfo->inputctl->eoi_reached) {
490 if (cinfo->input_scan_number == cinfo->output_scan_number) {
491 /* If input is working on current scan, we ordinarily want it to
492 * have completed the current row. But if input scan is DC,
493 * we want it to keep one row ahead so that next block row's DC
494 * values are up to date.
495 */
496 JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
497 if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
498 break;
499 }
500 if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
501 return JPEG_SUSPENDED;
502 }
503
504 /* OK, output from the virtual arrays. */
505 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
506 ci++, compptr++) {
507 /* Don't bother to IDCT an uninteresting component. */
508 if (! compptr->component_needed)
509 continue;
510 /* Count non-dummy DCT block rows in this iMCU row. */
511 if (cinfo->output_iMCU_row < last_iMCU_row) {
512 block_rows = compptr->v_samp_factor;
513 access_rows = block_rows * 2; /* this and next iMCU row */
514 last_row = FALSE;
515 } else {
516 /* NB: can't use last_row_height here; it is input-side-dependent! */
517 block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
518 if (block_rows == 0) block_rows = compptr->v_samp_factor;
519 access_rows = block_rows; /* this iMCU row only */
520 last_row = TRUE;
521 }
522 /* Align the virtual buffer for this component. */
523 if (cinfo->output_iMCU_row > 0) {
524 access_rows += compptr->v_samp_factor; /* prior iMCU row too */
525 buffer = (*cinfo->mem->access_virt_barray)
526 ((j_common_ptr) cinfo, coef->whole_image[ci],
527 (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
528 (JDIMENSION) access_rows, FALSE);
529 buffer += compptr->v_samp_factor; /* point to current iMCU row */
530 first_row = FALSE;
531 } else {
532 buffer = (*cinfo->mem->access_virt_barray)
533 ((j_common_ptr) cinfo, coef->whole_image[ci],
534 (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
535 first_row = TRUE;
536 }
537 /* Fetch component-dependent info */
538 coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
539 quanttbl = compptr->quant_table;
540 Q00 = quanttbl->quantval[0];
541 Q01 = quanttbl->quantval[Q01_POS];
542 Q10 = quanttbl->quantval[Q10_POS];
543 Q20 = quanttbl->quantval[Q20_POS];
544 Q11 = quanttbl->quantval[Q11_POS];
545 Q02 = quanttbl->quantval[Q02_POS];
546 inverse_DCT = cinfo->idct->inverse_DCT[ci];
547 output_ptr = output_buf[ci];
548 /* Loop over all DCT blocks to be processed. */
549 for (block_row = 0; block_row < block_rows; block_row++) {
550 buffer_ptr = buffer[block_row];
551 if (first_row && block_row == 0)
552 prev_block_row = buffer_ptr;
553 else
554 prev_block_row = buffer[block_row-1];
555 if (last_row && block_row == block_rows-1)
556 next_block_row = buffer_ptr;
557 else
558 next_block_row = buffer[block_row+1];
559 /* We fetch the surrounding DC values using a sliding-register approach.
560 * Initialize all nine here so as to do the right thing on narrow pics.
561 */
562 DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
563 DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
564 DC7 = DC8 = DC9 = (int) next_block_row[0][0];
565 output_col = 0;
566 last_block_column = compptr->width_in_blocks - 1;
567 for (block_num = 0; block_num <= last_block_column; block_num++) {
568 /* Fetch current DCT block into workspace so we can modify it. */
569 jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
570 /* Update DC values */
571 if (block_num < last_block_column) {
572 DC3 = (int) prev_block_row[1][0];
573 DC6 = (int) buffer_ptr[1][0];
574 DC9 = (int) next_block_row[1][0];
575 }
576 /* Compute coefficient estimates per K.8.
577 * An estimate is applied only if coefficient is still zero,
578 * and is not known to be fully accurate.
579 */
580 /* AC01 */
581 if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
582 num = 36 * Q00 * (DC4 - DC6);
583 if (num >= 0) {
584 pred = (int) (((Q01<<7) + num) / (Q01<<8));
585 if (Al > 0 && pred >= (1<<Al))
586 pred = (1<<Al)-1;
587 } else {
588 pred = (int) (((Q01<<7) - num) / (Q01<<8));
589 if (Al > 0 && pred >= (1<<Al))
590 pred = (1<<Al)-1;
591 pred = -pred;
592 }
593 workspace[1] = (JCOEF) pred;
594 }
595 /* AC10 */
596 if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
597 num = 36 * Q00 * (DC2 - DC8);
598 if (num >= 0) {
599 pred = (int) (((Q10<<7) + num) / (Q10<<8));
600 if (Al > 0 && pred >= (1<<Al))
601 pred = (1<<Al)-1;
602 } else {
603 pred = (int) (((Q10<<7) - num) / (Q10<<8));
604 if (Al > 0 && pred >= (1<<Al))
605 pred = (1<<Al)-1;
606 pred = -pred;
607 }
608 workspace[8] = (JCOEF) pred;
609 }
610 /* AC20 */
611 if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
612 num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
613 if (num >= 0) {
614 pred = (int) (((Q20<<7) + num) / (Q20<<8));
615 if (Al > 0 && pred >= (1<<Al))
616 pred = (1<<Al)-1;
617 } else {
618 pred = (int) (((Q20<<7) - num) / (Q20<<8));
619 if (Al > 0 && pred >= (1<<Al))
620 pred = (1<<Al)-1;
621 pred = -pred;
622 }
623 workspace[16] = (JCOEF) pred;
624 }
625 /* AC11 */
626 if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
627 num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
628 if (num >= 0) {
629 pred = (int) (((Q11<<7) + num) / (Q11<<8));
630 if (Al > 0 && pred >= (1<<Al))
631 pred = (1<<Al)-1;
632 } else {
633 pred = (int) (((Q11<<7) - num) / (Q11<<8));
634 if (Al > 0 && pred >= (1<<Al))
635 pred = (1<<Al)-1;
636 pred = -pred;
637 }
638 workspace[9] = (JCOEF) pred;
639 }
640 /* AC02 */
641 if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
642 num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
643 if (num >= 0) {
644 pred = (int) (((Q02<<7) + num) / (Q02<<8));
645 if (Al > 0 && pred >= (1<<Al))
646 pred = (1<<Al)-1;
647 } else {
648 pred = (int) (((Q02<<7) - num) / (Q02<<8));
649 if (Al > 0 && pred >= (1<<Al))
650 pred = (1<<Al)-1;
651 pred = -pred;
652 }
653 workspace[2] = (JCOEF) pred;
654 }
655 /* OK, do the IDCT */
656 (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
657 output_ptr, output_col);
658 /* Advance for next column */
659 DC1 = DC2; DC2 = DC3;
660 DC4 = DC5; DC5 = DC6;
661 DC7 = DC8; DC8 = DC9;
662 buffer_ptr++, prev_block_row++, next_block_row++;
663 output_col += compptr->DCT_scaled_size;
664 }
665 output_ptr += compptr->DCT_scaled_size;
666 }
667 }
668
669 if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
670 return JPEG_ROW_COMPLETED;
671 return JPEG_SCAN_COMPLETED;
672 }
673
674 #endif /* BLOCK_SMOOTHING_SUPPORTED */
675
676
677 /*
678 * Initialize coefficient buffer controller.
679 */
680
681 GLOBAL(void)
682 jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
683 {
684 my_coef_ptr coef;
685
686 coef = (my_coef_ptr)
687 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
688 SIZEOF(my_coef_controller));
689 cinfo->coef = (struct jpeg_d_coef_controller *) coef;
690 coef->pub.start_input_pass = start_input_pass;
691 coef->pub.start_output_pass = start_output_pass;
692 #ifdef BLOCK_SMOOTHING_SUPPORTED
693 coef->coef_bits_latch = NULL;
694 #endif
695
696 /* Create the coefficient buffer. */
697 if (need_full_buffer) {
698 #ifdef D_MULTISCAN_FILES_SUPPORTED
699 /* Allocate a full-image virtual array for each component, */
700 /* padded to a multiple of samp_factor DCT blocks in each direction. */
701 /* Note we ask for a pre-zeroed array. */
702 int ci, access_rows;
703 jpeg_component_info *compptr;
704
705 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
706 ci++, compptr++) {
707 access_rows = compptr->v_samp_factor;
708 #ifdef BLOCK_SMOOTHING_SUPPORTED
709 /* If block smoothing could be used, need a bigger window */
710 if (cinfo->progressive_mode)
711 access_rows *= 3;
712 #endif
713 coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
714 ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
715 (JDIMENSION) jround_up((long) compptr->width_in_blocks,
716 (long) compptr->h_samp_factor),
717 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
718 (long) compptr->v_samp_factor),
719 (JDIMENSION) access_rows);
720 }
721 coef->pub.consume_data = consume_data;
722 coef->pub.decompress_data = decompress_data;
723 coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
724 #else
725 ERREXIT(cinfo, JERR_NOT_COMPILED);
726 #endif
727 } else {
728 /* We only need a single-MCU buffer. */
729 JBLOCKROW buffer;
730 int i;
731
732 buffer = (JBLOCKROW)
733 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
734 D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
735 for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
736 coef->MCU_buffer[i] = buffer + i;
737 }
738 coef->pub.consume_data = dummy_consume_data;
739 coef->pub.decompress_data = decompress_onepass;
740 coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
741 }
742
743 /* Allocate the workspace buffer */
744 coef->workspace = (JCOEF *)
745 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
746 SIZEOF(JCOEF) * DCTSIZE2);
747 }
OLDNEW
« no previous file with comments | « third_party/libjpeg_turbo/jdatasrc.c ('k') | third_party/libjpeg_turbo/jdcolor.c » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698