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