4
* Copyright (C) 1995-1997, 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.
8
* This file contains Huffman entropy encoding routines for progressive JPEG.
10
* We do not support output suspension in this module, since the library
11
* currently does not allow multiple-scan files to be written with output
15
#define JPEG_INTERNALS
18
#include "jchuff.h" /* Declarations shared with jchuff.c */
20
#ifdef C_PROGRESSIVE_SUPPORTED
22
/* Expanded entropy encoder object for progressive Huffman encoding. */
25
struct jpeg_entropy_encoder pub; /* public fields */
27
/* Mode flag: TRUE for optimization, FALSE for actual data output */
28
wxjpeg_boolean gather_statistics;
30
/* Bit-level coding status.
31
* next_output_byte/free_in_buffer are local copies of cinfo->dest fields.
33
JOCTET * next_output_byte; /* => next byte to write in buffer */
34
size_t free_in_buffer; /* # of byte spaces remaining in buffer */
35
JPEG_INT32 put_buffer; /* current bit-accumulation buffer */
36
int put_bits; /* # of bits now in it */
37
j_compress_ptr cinfo; /* link to cinfo (needed for dump_buffer) */
39
/* Coding status for DC components */
40
int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
42
/* Coding status for AC components */
43
int ac_tbl_no; /* the table number of the single component */
44
unsigned int EOBRUN; /* run length of EOBs */
45
unsigned int BE; /* # of buffered correction bits before MCU */
46
char * bit_buffer; /* buffer for correction bits (1 per char) */
47
/* packing correction bits tightly would save some space but cost time... */
49
unsigned int restarts_to_go; /* MCUs left in this restart interval */
50
int next_restart_num; /* next restart number to write (0-7) */
52
/* Pointers to derived tables (these workspaces have image lifespan).
53
* Since any one scan codes only DC or only AC, we only need one set
54
* of tables, not one for DC and one for AC.
56
c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
58
/* Statistics tables for optimization; again, one set is enough */
59
long * count_ptrs[NUM_HUFF_TBLS];
60
} phuff_entropy_encoder;
62
typedef phuff_entropy_encoder * phuff_entropy_ptr;
64
/* MAX_CORR_BITS is the number of bits the AC refinement correction-bit
65
* buffer can hold. Larger sizes may slightly improve compression, but
66
* 1000 is already well into the realm of overkill.
67
* The minimum safe size is 64 bits.
70
#define MAX_CORR_BITS 1000 /* Max # of correction bits I can buffer */
72
/* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.
73
* We assume that int right shift is unsigned if INT32 right shift is,
74
* which should be safe.
77
#ifdef RIGHT_SHIFT_IS_UNSIGNED
78
#define ISHIFT_TEMPS int ishift_temp;
79
#define IRIGHT_SHIFT(x,shft) \
80
((ishift_temp = (x)) < 0 ? \
81
(ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
82
(ishift_temp >> (shft)))
85
#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
88
/* Forward declarations */
89
METHODDEF(wxjpeg_boolean) encode_mcu_DC_first JPP((j_compress_ptr cinfo,
90
JBLOCKROW *MCU_data));
91
METHODDEF(wxjpeg_boolean) encode_mcu_AC_first JPP((j_compress_ptr cinfo,
92
JBLOCKROW *MCU_data));
93
METHODDEF(wxjpeg_boolean) encode_mcu_DC_refine JPP((j_compress_ptr cinfo,
94
JBLOCKROW *MCU_data));
95
METHODDEF(wxjpeg_boolean) encode_mcu_AC_refine JPP((j_compress_ptr cinfo,
96
JBLOCKROW *MCU_data));
97
METHODDEF(void) finish_pass_phuff JPP((j_compress_ptr cinfo));
98
METHODDEF(void) finish_pass_gather_phuff JPP((j_compress_ptr cinfo));
102
* Initialize for a Huffman-compressed scan using progressive JPEG.
106
start_pass_phuff (j_compress_ptr cinfo, wxjpeg_boolean gather_statistics)
108
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
109
wxjpeg_boolean is_DC_band;
111
jpeg_component_info * compptr;
113
entropy->cinfo = cinfo;
114
entropy->gather_statistics = gather_statistics;
116
is_DC_band = (cinfo->Ss == 0);
118
/* We assume jcmaster.c already validated the scan parameters. */
120
/* Select execution routines */
121
if (cinfo->Ah == 0) {
123
entropy->pub.encode_mcu = encode_mcu_DC_first;
125
entropy->pub.encode_mcu = encode_mcu_AC_first;
128
entropy->pub.encode_mcu = encode_mcu_DC_refine;
130
entropy->pub.encode_mcu = encode_mcu_AC_refine;
131
/* AC refinement needs a correction bit buffer */
132
if (entropy->bit_buffer == NULL)
133
entropy->bit_buffer = (char *)
134
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
135
MAX_CORR_BITS * SIZEOF(char));
138
if (gather_statistics)
139
entropy->pub.finish_pass = finish_pass_gather_phuff;
141
entropy->pub.finish_pass = finish_pass_phuff;
143
/* Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1
144
* for AC coefficients.
146
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
147
compptr = cinfo->cur_comp_info[ci];
148
/* Initialize DC predictions to 0 */
149
entropy->last_dc_val[ci] = 0;
150
/* Get table index */
152
if (cinfo->Ah != 0) /* DC refinement needs no table */
154
tbl = compptr->dc_tbl_no;
156
entropy->ac_tbl_no = tbl = compptr->ac_tbl_no;
158
if (gather_statistics) {
159
/* Check for invalid table index */
160
/* (make_c_derived_tbl does this in the other path) */
161
if (tbl < 0 || tbl >= NUM_HUFF_TBLS)
162
ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);
163
/* Allocate and zero the statistics tables */
164
/* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
165
if (entropy->count_ptrs[tbl] == NULL)
166
entropy->count_ptrs[tbl] = (long *)
167
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
169
MEMZERO(entropy->count_ptrs[tbl], 257 * SIZEOF(long));
171
/* Compute derived values for Huffman table */
172
/* We may do this more than once for a table, but it's not expensive */
173
jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl,
174
& entropy->derived_tbls[tbl]);
178
/* Initialize AC stuff */
182
/* Initialize bit buffer to empty */
183
entropy->put_buffer = 0;
184
entropy->put_bits = 0;
186
/* Initialize restart stuff */
187
entropy->restarts_to_go = cinfo->restart_interval;
188
entropy->next_restart_num = 0;
192
/* Outputting bytes to the file.
193
* NB: these must be called only when actually outputting,
194
* that is, entropy->gather_statistics == FALSE.
198
#define emit_byte(entropy,val) \
199
{ *(entropy)->next_output_byte++ = (JOCTET) (val); \
200
if (--(entropy)->free_in_buffer == 0) \
201
dump_buffer(entropy); }
205
dump_buffer (phuff_entropy_ptr entropy)
206
/* Empty the output buffer; we do not support suspension in this module. */
208
struct jpeg_destination_mgr * dest = entropy->cinfo->dest;
210
if (! (*dest->empty_output_buffer) (entropy->cinfo))
211
ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND);
212
/* After a successful buffer dump, must reset buffer pointers */
213
entropy->next_output_byte = dest->next_output_byte;
214
entropy->free_in_buffer = dest->free_in_buffer;
218
/* Outputting bits to the file */
220
/* Only the right 24 bits of put_buffer are used; the valid bits are
221
* left-justified in this part. At most 16 bits can be passed to emit_bits
222
* in one call, and we never retain more than 7 bits in put_buffer
223
* between calls, so 24 bits are sufficient.
228
emit_bits (phuff_entropy_ptr entropy, unsigned int code, int size)
229
/* Emit some bits, unless we are in gather mode */
231
/* This routine is heavily used, so it's worth coding tightly. */
232
register JPEG_INT32 put_buffer = (JPEG_INT32) code;
233
register int put_bits = entropy->put_bits;
235
/* if size is 0, caller used an invalid Huffman table entry */
237
ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
239
if (entropy->gather_statistics)
240
return; /* do nothing if we're only getting stats */
242
put_buffer &= (((JPEG_INT32) 1)<<size) - 1; /* mask off any extra bits in code */
244
put_bits += size; /* new number of bits in buffer */
246
put_buffer <<= 24 - put_bits; /* align incoming bits */
248
put_buffer |= entropy->put_buffer; /* and merge with old buffer contents */
250
while (put_bits >= 8) {
251
int c = (int) ((put_buffer >> 16) & 0xFF);
253
emit_byte(entropy, c);
254
if (c == 0xFF) { /* need to stuff a zero byte? */
255
emit_byte(entropy, 0);
261
entropy->put_buffer = put_buffer; /* update variables */
262
entropy->put_bits = put_bits;
267
flush_bits (phuff_entropy_ptr entropy)
269
emit_bits(entropy, 0x7F, 7); /* fill any partial byte with ones */
270
entropy->put_buffer = 0; /* and reset bit-buffer to empty */
271
entropy->put_bits = 0;
276
* Emit (or just count) a Huffman symbol.
281
emit_symbol (phuff_entropy_ptr entropy, int tbl_no, int symbol)
283
if (entropy->gather_statistics)
284
entropy->count_ptrs[tbl_no][symbol]++;
286
c_derived_tbl * tbl = entropy->derived_tbls[tbl_no];
287
emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
293
* Emit bits from a correction bit buffer.
297
emit_buffered_bits (phuff_entropy_ptr entropy, char * bufstart,
300
if (entropy->gather_statistics)
301
return; /* no real work */
304
emit_bits(entropy, (unsigned int) (*bufstart), 1);
312
* Emit any pending EOBRUN symbol.
316
emit_eobrun (phuff_entropy_ptr entropy)
318
register int temp, nbits;
320
if (entropy->EOBRUN > 0) { /* if there is any pending EOBRUN */
321
temp = entropy->EOBRUN;
325
/* safety check: shouldn't happen given limited correction-bit buffer */
327
ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
329
emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
331
emit_bits(entropy, entropy->EOBRUN, nbits);
335
/* Emit any buffered correction bits */
336
emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);
343
* Emit a restart marker & resynchronize predictions.
347
emit_restart (phuff_entropy_ptr entropy, int restart_num)
351
emit_eobrun(entropy);
353
if (! entropy->gather_statistics) {
355
emit_byte(entropy, 0xFF);
356
emit_byte(entropy, JPEG_RST0 + restart_num);
359
if (entropy->cinfo->Ss == 0) {
360
/* Re-initialize DC predictions to 0 */
361
for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++)
362
entropy->last_dc_val[ci] = 0;
364
/* Re-initialize all AC-related fields to 0 */
372
* MCU encoding for DC initial scan (either spectral selection,
373
* or first pass of successive approximation).
376
METHODDEF(wxjpeg_boolean)
377
encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
379
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
380
register int temp, temp2;
385
jpeg_component_info * compptr;
388
entropy->next_output_byte = cinfo->dest->next_output_byte;
389
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
391
/* Emit restart marker if needed */
392
if (cinfo->restart_interval)
393
if (entropy->restarts_to_go == 0)
394
emit_restart(entropy, entropy->next_restart_num);
396
/* Encode the MCU data blocks */
397
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
398
block = MCU_data[blkn];
399
ci = cinfo->MCU_membership[blkn];
400
compptr = cinfo->cur_comp_info[ci];
402
/* Compute the DC value after the required point transform by Al.
403
* This is simply an arithmetic right shift.
405
temp2 = IRIGHT_SHIFT((int) ((*block)[0]), Al);
407
/* DC differences are figured on the point-transformed values. */
408
temp = temp2 - entropy->last_dc_val[ci];
409
entropy->last_dc_val[ci] = temp2;
411
/* Encode the DC coefficient difference per section G.1.2.1 */
414
temp = -temp; /* temp is abs value of input */
415
/* For a negative input, want temp2 = bitwise complement of abs(input) */
416
/* This code assumes we are on a two's complement machine */
420
/* Find the number of bits needed for the magnitude of the coefficient */
426
/* Check for out-of-range coefficient values.
427
* Since we're encoding a difference, the range limit is twice as much.
429
if (nbits > MAX_COEF_BITS+1)
430
ERREXIT(cinfo, JERR_BAD_DCT_COEF);
432
/* Count/emit the Huffman-coded symbol for the number of bits */
433
emit_symbol(entropy, compptr->dc_tbl_no, nbits);
435
/* Emit that number of bits of the value, if positive, */
436
/* or the complement of its magnitude, if negative. */
437
if (nbits) /* emit_bits rejects calls with size 0 */
438
emit_bits(entropy, (unsigned int) temp2, nbits);
441
cinfo->dest->next_output_byte = entropy->next_output_byte;
442
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
444
/* Update restart-interval state too */
445
if (cinfo->restart_interval) {
446
if (entropy->restarts_to_go == 0) {
447
entropy->restarts_to_go = cinfo->restart_interval;
448
entropy->next_restart_num++;
449
entropy->next_restart_num &= 7;
451
entropy->restarts_to_go--;
459
* MCU encoding for AC initial scan (either spectral selection,
460
* or first pass of successive approximation).
463
METHODDEF(wxjpeg_boolean)
464
encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
466
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
467
register int temp, temp2;
474
entropy->next_output_byte = cinfo->dest->next_output_byte;
475
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
477
/* Emit restart marker if needed */
478
if (cinfo->restart_interval)
479
if (entropy->restarts_to_go == 0)
480
emit_restart(entropy, entropy->next_restart_num);
482
/* Encode the MCU data block */
485
/* Encode the AC coefficients per section G.1.2.2, fig. G.3 */
487
r = 0; /* r = run length of zeros */
489
for (k = cinfo->Ss; k <= Se; k++) {
490
if ((temp = (*block)[jpeg_natural_order[k]]) == 0) {
494
/* We must apply the point transform by Al. For AC coefficients this
495
* is an integer division with rounding towards 0. To do this portably
496
* in C, we shift after obtaining the absolute value; so the code is
497
* interwoven with finding the abs value (temp) and output bits (temp2).
500
temp = -temp; /* temp is abs value of input */
501
temp >>= Al; /* apply the point transform */
502
/* For a negative coef, want temp2 = bitwise complement of abs(coef) */
505
temp >>= Al; /* apply the point transform */
508
/* Watch out for case that nonzero coef is zero after point transform */
514
/* Emit any pending EOBRUN */
515
if (entropy->EOBRUN > 0)
516
emit_eobrun(entropy);
517
/* if run length > 15, must emit special run-length-16 codes (0xF0) */
519
emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
523
/* Find the number of bits needed for the magnitude of the coefficient */
524
nbits = 1; /* there must be at least one 1 bit */
527
/* Check for out-of-range coefficient values */
528
if (nbits > MAX_COEF_BITS)
529
ERREXIT(cinfo, JERR_BAD_DCT_COEF);
531
/* Count/emit Huffman symbol for run length / number of bits */
532
emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + nbits);
534
/* Emit that number of bits of the value, if positive, */
535
/* or the complement of its magnitude, if negative. */
536
emit_bits(entropy, (unsigned int) temp2, nbits);
538
r = 0; /* reset zero run length */
541
if (r > 0) { /* If there are trailing zeroes, */
542
entropy->EOBRUN++; /* count an EOB */
543
if (entropy->EOBRUN == 0x7FFF)
544
emit_eobrun(entropy); /* force it out to avoid overflow */
547
cinfo->dest->next_output_byte = entropy->next_output_byte;
548
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
550
/* Update restart-interval state too */
551
if (cinfo->restart_interval) {
552
if (entropy->restarts_to_go == 0) {
553
entropy->restarts_to_go = cinfo->restart_interval;
554
entropy->next_restart_num++;
555
entropy->next_restart_num &= 7;
557
entropy->restarts_to_go--;
565
* MCU encoding for DC successive approximation refinement scan.
566
* Note: we assume such scans can be multi-component, although the spec
567
* is not very clear on the point.
570
METHODDEF(wxjpeg_boolean)
571
encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
573
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
579
entropy->next_output_byte = cinfo->dest->next_output_byte;
580
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
582
/* Emit restart marker if needed */
583
if (cinfo->restart_interval)
584
if (entropy->restarts_to_go == 0)
585
emit_restart(entropy, entropy->next_restart_num);
587
/* Encode the MCU data blocks */
588
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
589
block = MCU_data[blkn];
591
/* We simply emit the Al'th bit of the DC coefficient value. */
593
emit_bits(entropy, (unsigned int) (temp >> Al), 1);
596
cinfo->dest->next_output_byte = entropy->next_output_byte;
597
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
599
/* Update restart-interval state too */
600
if (cinfo->restart_interval) {
601
if (entropy->restarts_to_go == 0) {
602
entropy->restarts_to_go = cinfo->restart_interval;
603
entropy->next_restart_num++;
604
entropy->next_restart_num &= 7;
606
entropy->restarts_to_go--;
614
* MCU encoding for AC successive approximation refinement scan.
617
METHODDEF(wxjpeg_boolean)
618
encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
620
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
629
int absvalues[DCTSIZE2];
631
entropy->next_output_byte = cinfo->dest->next_output_byte;
632
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
634
/* Emit restart marker if needed */
635
if (cinfo->restart_interval)
636
if (entropy->restarts_to_go == 0)
637
emit_restart(entropy, entropy->next_restart_num);
639
/* Encode the MCU data block */
642
/* It is convenient to make a pre-pass to determine the transformed
643
* coefficients' absolute values and the EOB position.
646
for (k = cinfo->Ss; k <= Se; k++) {
647
temp = (*block)[jpeg_natural_order[k]];
648
/* We must apply the point transform by Al. For AC coefficients this
649
* is an integer division with rounding towards 0. To do this portably
650
* in C, we shift after obtaining the absolute value.
653
temp = -temp; /* temp is abs value of input */
654
temp >>= Al; /* apply the point transform */
655
absvalues[k] = temp; /* save abs value for main pass */
657
EOB = k; /* EOB = index of last newly-nonzero coef */
660
/* Encode the AC coefficients per section G.1.2.3, fig. G.7 */
662
r = 0; /* r = run length of zeros */
663
BR = 0; /* BR = count of buffered bits added now */
664
BR_buffer = entropy->bit_buffer + entropy->BE; /* Append bits to buffer */
666
for (k = cinfo->Ss; k <= Se; k++) {
667
if ((temp = absvalues[k]) == 0) {
672
/* Emit any required ZRLs, but not if they can be folded into EOB */
673
while (r > 15 && k <= EOB) {
674
/* emit any pending EOBRUN and the BE correction bits */
675
emit_eobrun(entropy);
677
emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
679
/* Emit buffered correction bits that must be associated with ZRL */
680
emit_buffered_bits(entropy, BR_buffer, BR);
681
BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
685
/* If the coef was previously nonzero, it only needs a correction bit.
686
* NOTE: a straight translation of the spec's figure G.7 would suggest
687
* that we also need to test r > 15. But if r > 15, we can only get here
688
* if k > EOB, which implies that this coefficient is not 1.
691
/* The correction bit is the next bit of the absolute value. */
692
BR_buffer[BR++] = (char) (temp & 1);
696
/* Emit any pending EOBRUN and the BE correction bits */
697
emit_eobrun(entropy);
699
/* Count/emit Huffman symbol for run length / number of bits */
700
emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1);
702
/* Emit output bit for newly-nonzero coef */
703
temp = ((*block)[jpeg_natural_order[k]] < 0) ? 0 : 1;
704
emit_bits(entropy, (unsigned int) temp, 1);
706
/* Emit buffered correction bits that must be associated with this code */
707
emit_buffered_bits(entropy, BR_buffer, BR);
708
BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
710
r = 0; /* reset zero run length */
713
if (r > 0 || BR > 0) { /* If there are trailing zeroes, */
714
entropy->EOBRUN++; /* count an EOB */
715
entropy->BE += BR; /* concat my correction bits to older ones */
716
/* We force out the EOB if we risk either:
717
* 1. overflow of the EOB counter;
718
* 2. overflow of the correction bit buffer during the next MCU.
720
if (entropy->EOBRUN == 0x7FFF || entropy->BE > (MAX_CORR_BITS-DCTSIZE2+1))
721
emit_eobrun(entropy);
724
cinfo->dest->next_output_byte = entropy->next_output_byte;
725
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
727
/* Update restart-interval state too */
728
if (cinfo->restart_interval) {
729
if (entropy->restarts_to_go == 0) {
730
entropy->restarts_to_go = cinfo->restart_interval;
731
entropy->next_restart_num++;
732
entropy->next_restart_num &= 7;
734
entropy->restarts_to_go--;
742
* Finish up at the end of a Huffman-compressed progressive scan.
746
finish_pass_phuff (j_compress_ptr cinfo)
748
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
750
entropy->next_output_byte = cinfo->dest->next_output_byte;
751
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
753
/* Flush out any buffered data */
754
emit_eobrun(entropy);
757
cinfo->dest->next_output_byte = entropy->next_output_byte;
758
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
763
* Finish up a statistics-gathering pass and create the new Huffman tables.
767
finish_pass_gather_phuff (j_compress_ptr cinfo)
769
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
770
wxjpeg_boolean is_DC_band;
772
jpeg_component_info * compptr;
774
wxjpeg_boolean did[NUM_HUFF_TBLS];
776
/* Flush out buffered data (all we care about is counting the EOB symbol) */
777
emit_eobrun(entropy);
779
is_DC_band = (cinfo->Ss == 0);
781
/* It's important not to apply jpeg_gen_optimal_table more than once
782
* per table, because it clobbers the input frequency counts!
784
MEMZERO(did, SIZEOF(did));
786
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
787
compptr = cinfo->cur_comp_info[ci];
789
if (cinfo->Ah != 0) /* DC refinement needs no table */
791
tbl = compptr->dc_tbl_no;
793
tbl = compptr->ac_tbl_no;
797
htblptr = & cinfo->dc_huff_tbl_ptrs[tbl];
799
htblptr = & cinfo->ac_huff_tbl_ptrs[tbl];
800
if (*htblptr == NULL)
801
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
802
jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[tbl]);
810
* Module initialization routine for progressive Huffman entropy encoding.
814
jinit_phuff_encoder (j_compress_ptr cinfo)
816
phuff_entropy_ptr entropy;
819
entropy = (phuff_entropy_ptr)
820
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
821
SIZEOF(phuff_entropy_encoder));
822
cinfo->entropy = (struct jpeg_entropy_encoder *) entropy;
823
entropy->pub.start_pass = start_pass_phuff;
825
/* Mark tables unallocated */
826
for (i = 0; i < NUM_HUFF_TBLS; i++) {
827
entropy->derived_tbls[i] = NULL;
828
entropy->count_ptrs[i] = NULL;
830
entropy->bit_buffer = NULL; /* needed only in AC refinement scan */
833
#endif /* C_PROGRESSIVE_SUPPORTED */
added
removed
src/jpeg/jcphuff.c
