/src/libjpeg-turbo/src/jcphuff.c
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1 | | /* |
2 | | * jcphuff.c |
3 | | * |
4 | | * This file was part of the Independent JPEG Group's software: |
5 | | * Copyright (C) 1995-1997, Thomas G. Lane. |
6 | | * Lossless JPEG Modifications: |
7 | | * Copyright (C) 1999, Ken Murchison. |
8 | | * libjpeg-turbo Modifications: |
9 | | * Copyright (C) 2011, 2015, 2018, 2021-2022, 2024, D. R. Commander. |
10 | | * Copyright (C) 2016, 2018, 2022, Matthieu Darbois. |
11 | | * Copyright (C) 2020, Arm Limited. |
12 | | * Copyright (C) 2021, Alex Richardson. |
13 | | * For conditions of distribution and use, see the accompanying README.ijg |
14 | | * file. |
15 | | * |
16 | | * This file contains Huffman entropy encoding routines for progressive JPEG. |
17 | | * |
18 | | * We do not support output suspension in this module, since the library |
19 | | * currently does not allow multiple-scan files to be written with output |
20 | | * suspension. |
21 | | */ |
22 | | |
23 | | #define JPEG_INTERNALS |
24 | | #include "jinclude.h" |
25 | | #include "jpeglib.h" |
26 | | #ifdef WITH_SIMD |
27 | | #include "jsimd.h" |
28 | | #else |
29 | | #include "jchuff.h" /* Declarations shared with jc*huff.c */ |
30 | | #endif |
31 | | #include <limits.h> |
32 | | |
33 | | #ifdef HAVE_INTRIN_H |
34 | | #include <intrin.h> |
35 | | #ifdef _MSC_VER |
36 | | #ifdef HAVE_BITSCANFORWARD64 |
37 | | #pragma intrinsic(_BitScanForward64) |
38 | | #endif |
39 | | #ifdef HAVE_BITSCANFORWARD |
40 | | #pragma intrinsic(_BitScanForward) |
41 | | #endif |
42 | | #endif |
43 | | #endif |
44 | | |
45 | | #ifdef C_PROGRESSIVE_SUPPORTED |
46 | | |
47 | | #include "jpeg_nbits.h" |
48 | | |
49 | | |
50 | | /* Expanded entropy encoder object for progressive Huffman encoding. */ |
51 | | |
52 | | typedef struct { |
53 | | struct jpeg_entropy_encoder pub; /* public fields */ |
54 | | |
55 | | /* Pointer to routine to prepare data for encode_mcu_AC_first() */ |
56 | | void (*AC_first_prepare) (const JCOEF *block, |
57 | | const int *jpeg_natural_order_start, int Sl, |
58 | | int Al, UJCOEF *values, size_t *zerobits); |
59 | | /* Pointer to routine to prepare data for encode_mcu_AC_refine() */ |
60 | | int (*AC_refine_prepare) (const JCOEF *block, |
61 | | const int *jpeg_natural_order_start, int Sl, |
62 | | int Al, UJCOEF *absvalues, size_t *bits); |
63 | | |
64 | | /* Mode flag: TRUE for optimization, FALSE for actual data output */ |
65 | | boolean gather_statistics; |
66 | | |
67 | | /* Bit-level coding status. |
68 | | * next_output_byte/free_in_buffer are local copies of cinfo->dest fields. |
69 | | */ |
70 | | JOCTET *next_output_byte; /* => next byte to write in buffer */ |
71 | | size_t free_in_buffer; /* # of byte spaces remaining in buffer */ |
72 | | size_t put_buffer; /* current bit-accumulation buffer */ |
73 | | int put_bits; /* # of bits now in it */ |
74 | | j_compress_ptr cinfo; /* link to cinfo (needed for dump_buffer) */ |
75 | | |
76 | | /* Coding status for DC components */ |
77 | | int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */ |
78 | | |
79 | | /* Coding status for AC components */ |
80 | | int ac_tbl_no; /* the table number of the single component */ |
81 | | unsigned int EOBRUN; /* run length of EOBs */ |
82 | | unsigned int BE; /* # of buffered correction bits before MCU */ |
83 | | char *bit_buffer; /* buffer for correction bits (1 per char) */ |
84 | | /* packing correction bits tightly would save some space but cost time... */ |
85 | | |
86 | | unsigned int restarts_to_go; /* MCUs left in this restart interval */ |
87 | | int next_restart_num; /* next restart number to write (0-7) */ |
88 | | |
89 | | /* Pointers to derived tables (these workspaces have image lifespan). |
90 | | * Since any one scan codes only DC or only AC, we only need one set |
91 | | * of tables, not one for DC and one for AC. |
92 | | */ |
93 | | c_derived_tbl *derived_tbls[NUM_HUFF_TBLS]; |
94 | | |
95 | | /* Statistics tables for optimization; again, one set is enough */ |
96 | | long *count_ptrs[NUM_HUFF_TBLS]; |
97 | | } phuff_entropy_encoder; |
98 | | |
99 | | typedef phuff_entropy_encoder *phuff_entropy_ptr; |
100 | | |
101 | | /* MAX_CORR_BITS is the number of bits the AC refinement correction-bit |
102 | | * buffer can hold. Larger sizes may slightly improve compression, but |
103 | | * 1000 is already well into the realm of overkill. |
104 | | * The minimum safe size is 64 bits. |
105 | | */ |
106 | | |
107 | 0 | #define MAX_CORR_BITS 1000 /* Max # of correction bits I can buffer */ |
108 | | |
109 | | /* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than JLONG. |
110 | | * We assume that int right shift is unsigned if JLONG right shift is, |
111 | | * which should be safe. |
112 | | */ |
113 | | |
114 | | #ifdef RIGHT_SHIFT_IS_UNSIGNED |
115 | | #define ISHIFT_TEMPS int ishift_temp; |
116 | | #define IRIGHT_SHIFT(x, shft) \ |
117 | | ((ishift_temp = (x)) < 0 ? \ |
118 | | (ishift_temp >> (shft)) | ((~0) << (16 - (shft))) : \ |
119 | | (ishift_temp >> (shft))) |
120 | | #else |
121 | | #define ISHIFT_TEMPS |
122 | 0 | #define IRIGHT_SHIFT(x, shft) ((x) >> (shft)) |
123 | | #endif |
124 | | |
125 | 0 | #define PAD(v, p) ((v + (p) - 1) & (~((p) - 1))) |
126 | | |
127 | | /* Forward declarations */ |
128 | | METHODDEF(boolean) encode_mcu_DC_first(j_compress_ptr cinfo, |
129 | | JBLOCKROW *MCU_data); |
130 | | METHODDEF(void) encode_mcu_AC_first_prepare |
131 | | (const JCOEF *block, const int *jpeg_natural_order_start, int Sl, int Al, |
132 | | UJCOEF *values, size_t *zerobits); |
133 | | METHODDEF(boolean) encode_mcu_AC_first(j_compress_ptr cinfo, |
134 | | JBLOCKROW *MCU_data); |
135 | | METHODDEF(boolean) encode_mcu_DC_refine(j_compress_ptr cinfo, |
136 | | JBLOCKROW *MCU_data); |
137 | | METHODDEF(int) encode_mcu_AC_refine_prepare |
138 | | (const JCOEF *block, const int *jpeg_natural_order_start, int Sl, int Al, |
139 | | UJCOEF *absvalues, size_t *bits); |
140 | | METHODDEF(boolean) encode_mcu_AC_refine(j_compress_ptr cinfo, |
141 | | JBLOCKROW *MCU_data); |
142 | | METHODDEF(void) finish_pass_phuff(j_compress_ptr cinfo); |
143 | | METHODDEF(void) finish_pass_gather_phuff(j_compress_ptr cinfo); |
144 | | |
145 | | |
146 | | /* Count bit loop zeroes */ |
147 | | INLINE |
148 | | METHODDEF(int) |
149 | | count_zeroes(size_t *x) |
150 | 0 | { |
151 | 0 | #if defined(HAVE_BUILTIN_CTZL) |
152 | 0 | int result; |
153 | 0 | result = __builtin_ctzl(*x); |
154 | 0 | *x >>= result; |
155 | | #elif defined(HAVE_BITSCANFORWARD64) |
156 | | unsigned long result; |
157 | | _BitScanForward64(&result, *x); |
158 | | *x >>= result; |
159 | | #elif defined(HAVE_BITSCANFORWARD) |
160 | | unsigned long result; |
161 | | _BitScanForward(&result, *x); |
162 | | *x >>= result; |
163 | | #else |
164 | | int result = 0; |
165 | | while ((*x & 1) == 0) { |
166 | | ++result; |
167 | | *x >>= 1; |
168 | | } |
169 | | #endif |
170 | 0 | return (int)result; |
171 | 0 | } |
172 | | |
173 | | |
174 | | /* |
175 | | * Initialize for a Huffman-compressed scan using progressive JPEG. |
176 | | */ |
177 | | |
178 | | METHODDEF(void) |
179 | | start_pass_phuff(j_compress_ptr cinfo, boolean gather_statistics) |
180 | 0 | { |
181 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
182 | 0 | boolean is_DC_band; |
183 | 0 | int ci, tbl; |
184 | 0 | jpeg_component_info *compptr; |
185 | |
|
186 | 0 | entropy->cinfo = cinfo; |
187 | 0 | entropy->gather_statistics = gather_statistics; |
188 | |
|
189 | 0 | is_DC_band = (cinfo->Ss == 0); |
190 | | |
191 | | /* We assume jcmaster.c already validated the scan parameters. */ |
192 | | |
193 | | /* Select execution routines */ |
194 | 0 | if (cinfo->Ah == 0) { |
195 | 0 | if (is_DC_band) |
196 | 0 | entropy->pub.encode_mcu = encode_mcu_DC_first; |
197 | 0 | else |
198 | 0 | entropy->pub.encode_mcu = encode_mcu_AC_first; |
199 | 0 | #ifdef WITH_SIMD |
200 | 0 | if (jsimd_can_encode_mcu_AC_first_prepare()) |
201 | 0 | entropy->AC_first_prepare = jsimd_encode_mcu_AC_first_prepare; |
202 | 0 | else |
203 | 0 | #endif |
204 | 0 | entropy->AC_first_prepare = encode_mcu_AC_first_prepare; |
205 | 0 | } else { |
206 | 0 | if (is_DC_band) |
207 | 0 | entropy->pub.encode_mcu = encode_mcu_DC_refine; |
208 | 0 | else { |
209 | 0 | entropy->pub.encode_mcu = encode_mcu_AC_refine; |
210 | 0 | #ifdef WITH_SIMD |
211 | 0 | if (jsimd_can_encode_mcu_AC_refine_prepare()) |
212 | 0 | entropy->AC_refine_prepare = jsimd_encode_mcu_AC_refine_prepare; |
213 | 0 | else |
214 | 0 | #endif |
215 | 0 | entropy->AC_refine_prepare = encode_mcu_AC_refine_prepare; |
216 | | /* AC refinement needs a correction bit buffer */ |
217 | 0 | if (entropy->bit_buffer == NULL) |
218 | 0 | entropy->bit_buffer = (char *) |
219 | 0 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
220 | 0 | MAX_CORR_BITS * sizeof(char)); |
221 | 0 | } |
222 | 0 | } |
223 | 0 | if (gather_statistics) |
224 | 0 | entropy->pub.finish_pass = finish_pass_gather_phuff; |
225 | 0 | else |
226 | 0 | entropy->pub.finish_pass = finish_pass_phuff; |
227 | | |
228 | | /* Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1 |
229 | | * for AC coefficients. |
230 | | */ |
231 | 0 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
232 | 0 | compptr = cinfo->cur_comp_info[ci]; |
233 | | /* Initialize DC predictions to 0 */ |
234 | 0 | entropy->last_dc_val[ci] = 0; |
235 | | /* Get table index */ |
236 | 0 | if (is_DC_band) { |
237 | 0 | if (cinfo->Ah != 0) /* DC refinement needs no table */ |
238 | 0 | continue; |
239 | 0 | tbl = compptr->dc_tbl_no; |
240 | 0 | } else { |
241 | 0 | entropy->ac_tbl_no = tbl = compptr->ac_tbl_no; |
242 | 0 | } |
243 | 0 | if (gather_statistics) { |
244 | | /* Check for invalid table index */ |
245 | | /* (make_c_derived_tbl does this in the other path) */ |
246 | 0 | if (tbl < 0 || tbl >= NUM_HUFF_TBLS) |
247 | 0 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl); |
248 | | /* Allocate and zero the statistics tables */ |
249 | | /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */ |
250 | 0 | if (entropy->count_ptrs[tbl] == NULL) |
251 | 0 | entropy->count_ptrs[tbl] = (long *) |
252 | 0 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
253 | 0 | 257 * sizeof(long)); |
254 | 0 | memset(entropy->count_ptrs[tbl], 0, 257 * sizeof(long)); |
255 | 0 | } else { |
256 | | /* Compute derived values for Huffman table */ |
257 | | /* We may do this more than once for a table, but it's not expensive */ |
258 | 0 | jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl, |
259 | 0 | &entropy->derived_tbls[tbl]); |
260 | 0 | } |
261 | 0 | } |
262 | | |
263 | | /* Initialize AC stuff */ |
264 | 0 | entropy->EOBRUN = 0; |
265 | 0 | entropy->BE = 0; |
266 | | |
267 | | /* Initialize bit buffer to empty */ |
268 | 0 | entropy->put_buffer = 0; |
269 | 0 | entropy->put_bits = 0; |
270 | | |
271 | | /* Initialize restart stuff */ |
272 | 0 | entropy->restarts_to_go = cinfo->restart_interval; |
273 | 0 | entropy->next_restart_num = 0; |
274 | 0 | } |
275 | | |
276 | | |
277 | | /* Outputting bytes to the file. |
278 | | * NB: these must be called only when actually outputting, |
279 | | * that is, entropy->gather_statistics == FALSE. |
280 | | */ |
281 | | |
282 | | /* Emit a byte */ |
283 | 0 | #define emit_byte(entropy, val) { \ |
284 | 0 | *(entropy)->next_output_byte++ = (JOCTET)(val); \ |
285 | 0 | if (--(entropy)->free_in_buffer == 0) \ |
286 | 0 | dump_buffer(entropy); \ |
287 | 0 | } |
288 | | |
289 | | |
290 | | LOCAL(void) |
291 | | dump_buffer(phuff_entropy_ptr entropy) |
292 | | /* Empty the output buffer; we do not support suspension in this module. */ |
293 | 0 | { |
294 | 0 | struct jpeg_destination_mgr *dest = entropy->cinfo->dest; |
295 | |
|
296 | 0 | if (!(*dest->empty_output_buffer) (entropy->cinfo)) |
297 | 0 | ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND); |
298 | | /* After a successful buffer dump, must reset buffer pointers */ |
299 | 0 | entropy->next_output_byte = dest->next_output_byte; |
300 | 0 | entropy->free_in_buffer = dest->free_in_buffer; |
301 | 0 | } |
302 | | |
303 | | |
304 | | /* Outputting bits to the file */ |
305 | | |
306 | | /* Only the right 24 bits of put_buffer are used; the valid bits are |
307 | | * left-justified in this part. At most 16 bits can be passed to emit_bits |
308 | | * in one call, and we never retain more than 7 bits in put_buffer |
309 | | * between calls, so 24 bits are sufficient. |
310 | | */ |
311 | | |
312 | | LOCAL(void) |
313 | | emit_bits(phuff_entropy_ptr entropy, unsigned int code, int size) |
314 | | /* Emit some bits, unless we are in gather mode */ |
315 | 0 | { |
316 | | /* This routine is heavily used, so it's worth coding tightly. */ |
317 | 0 | register size_t put_buffer = (size_t)code; |
318 | 0 | register int put_bits = entropy->put_bits; |
319 | | |
320 | | /* if size is 0, caller used an invalid Huffman table entry */ |
321 | 0 | if (size == 0) |
322 | 0 | ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE); |
323 | |
|
324 | 0 | if (entropy->gather_statistics) |
325 | 0 | return; /* do nothing if we're only getting stats */ |
326 | | |
327 | 0 | put_buffer &= (((size_t)1) << size) - 1; /* mask off any extra bits in code */ |
328 | |
|
329 | 0 | put_bits += size; /* new number of bits in buffer */ |
330 | |
|
331 | 0 | put_buffer <<= 24 - put_bits; /* align incoming bits */ |
332 | |
|
333 | 0 | put_buffer |= entropy->put_buffer; /* and merge with old buffer contents */ |
334 | |
|
335 | 0 | while (put_bits >= 8) { |
336 | 0 | int c = (int)((put_buffer >> 16) & 0xFF); |
337 | |
|
338 | 0 | emit_byte(entropy, c); |
339 | 0 | if (c == 0xFF) { /* need to stuff a zero byte? */ |
340 | 0 | emit_byte(entropy, 0); |
341 | 0 | } |
342 | 0 | put_buffer <<= 8; |
343 | 0 | put_bits -= 8; |
344 | 0 | } |
345 | |
|
346 | 0 | entropy->put_buffer = put_buffer; /* update variables */ |
347 | 0 | entropy->put_bits = put_bits; |
348 | 0 | } |
349 | | |
350 | | |
351 | | LOCAL(void) |
352 | | flush_bits(phuff_entropy_ptr entropy) |
353 | 0 | { |
354 | 0 | emit_bits(entropy, 0x7F, 7); /* fill any partial byte with ones */ |
355 | 0 | entropy->put_buffer = 0; /* and reset bit-buffer to empty */ |
356 | 0 | entropy->put_bits = 0; |
357 | 0 | } |
358 | | |
359 | | |
360 | | /* |
361 | | * Emit (or just count) a Huffman symbol. |
362 | | */ |
363 | | |
364 | | LOCAL(void) |
365 | | emit_symbol(phuff_entropy_ptr entropy, int tbl_no, int symbol) |
366 | 0 | { |
367 | 0 | if (entropy->gather_statistics) |
368 | 0 | entropy->count_ptrs[tbl_no][symbol]++; |
369 | 0 | else { |
370 | 0 | c_derived_tbl *tbl = entropy->derived_tbls[tbl_no]; |
371 | 0 | emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]); |
372 | 0 | } |
373 | 0 | } |
374 | | |
375 | | |
376 | | /* |
377 | | * Emit bits from a correction bit buffer. |
378 | | */ |
379 | | |
380 | | LOCAL(void) |
381 | | emit_buffered_bits(phuff_entropy_ptr entropy, char *bufstart, |
382 | | unsigned int nbits) |
383 | 0 | { |
384 | 0 | if (entropy->gather_statistics) |
385 | 0 | return; /* no real work */ |
386 | | |
387 | 0 | while (nbits > 0) { |
388 | 0 | emit_bits(entropy, (unsigned int)(*bufstart), 1); |
389 | 0 | bufstart++; |
390 | 0 | nbits--; |
391 | 0 | } |
392 | 0 | } |
393 | | |
394 | | |
395 | | /* |
396 | | * Emit any pending EOBRUN symbol. |
397 | | */ |
398 | | |
399 | | LOCAL(void) |
400 | | emit_eobrun(phuff_entropy_ptr entropy) |
401 | 0 | { |
402 | 0 | register int temp, nbits; |
403 | |
|
404 | 0 | if (entropy->EOBRUN > 0) { /* if there is any pending EOBRUN */ |
405 | 0 | temp = entropy->EOBRUN; |
406 | 0 | nbits = JPEG_NBITS_NONZERO(temp) - 1; |
407 | | /* safety check: shouldn't happen given limited correction-bit buffer */ |
408 | 0 | if (nbits > 14) |
409 | 0 | ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE); |
410 | |
|
411 | 0 | emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4); |
412 | 0 | if (nbits) |
413 | 0 | emit_bits(entropy, entropy->EOBRUN, nbits); |
414 | |
|
415 | 0 | entropy->EOBRUN = 0; |
416 | | |
417 | | /* Emit any buffered correction bits */ |
418 | 0 | emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE); |
419 | 0 | entropy->BE = 0; |
420 | 0 | } |
421 | 0 | } |
422 | | |
423 | | |
424 | | /* |
425 | | * Emit a restart marker & resynchronize predictions. |
426 | | */ |
427 | | |
428 | | LOCAL(void) |
429 | | emit_restart(phuff_entropy_ptr entropy, int restart_num) |
430 | 0 | { |
431 | 0 | int ci; |
432 | |
|
433 | 0 | emit_eobrun(entropy); |
434 | |
|
435 | 0 | if (!entropy->gather_statistics) { |
436 | 0 | flush_bits(entropy); |
437 | 0 | emit_byte(entropy, 0xFF); |
438 | 0 | emit_byte(entropy, JPEG_RST0 + restart_num); |
439 | 0 | } |
440 | |
|
441 | 0 | if (entropy->cinfo->Ss == 0) { |
442 | | /* Re-initialize DC predictions to 0 */ |
443 | 0 | for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++) |
444 | 0 | entropy->last_dc_val[ci] = 0; |
445 | 0 | } else { |
446 | | /* Re-initialize all AC-related fields to 0 */ |
447 | 0 | entropy->EOBRUN = 0; |
448 | 0 | entropy->BE = 0; |
449 | 0 | } |
450 | 0 | } |
451 | | |
452 | | |
453 | | /* |
454 | | * MCU encoding for DC initial scan (either spectral selection, |
455 | | * or first pass of successive approximation). |
456 | | */ |
457 | | |
458 | | METHODDEF(boolean) |
459 | | encode_mcu_DC_first(j_compress_ptr cinfo, JBLOCKROW *MCU_data) |
460 | 0 | { |
461 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
462 | 0 | register int temp, temp2, temp3; |
463 | 0 | register int nbits; |
464 | 0 | int blkn, ci; |
465 | 0 | int Al = cinfo->Al; |
466 | 0 | JBLOCKROW block; |
467 | 0 | jpeg_component_info *compptr; |
468 | 0 | ISHIFT_TEMPS |
469 | 0 | int max_coef_bits = cinfo->data_precision + 2; |
470 | |
|
471 | 0 | entropy->next_output_byte = cinfo->dest->next_output_byte; |
472 | 0 | entropy->free_in_buffer = cinfo->dest->free_in_buffer; |
473 | | |
474 | | /* Emit restart marker if needed */ |
475 | 0 | if (cinfo->restart_interval) |
476 | 0 | if (entropy->restarts_to_go == 0) |
477 | 0 | emit_restart(entropy, entropy->next_restart_num); |
478 | | |
479 | | /* Encode the MCU data blocks */ |
480 | 0 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { |
481 | 0 | block = MCU_data[blkn]; |
482 | 0 | ci = cinfo->MCU_membership[blkn]; |
483 | 0 | compptr = cinfo->cur_comp_info[ci]; |
484 | | |
485 | | /* Compute the DC value after the required point transform by Al. |
486 | | * This is simply an arithmetic right shift. |
487 | | */ |
488 | 0 | temp2 = IRIGHT_SHIFT((int)((*block)[0]), Al); |
489 | | |
490 | | /* DC differences are figured on the point-transformed values. */ |
491 | 0 | temp = temp2 - entropy->last_dc_val[ci]; |
492 | 0 | entropy->last_dc_val[ci] = temp2; |
493 | | |
494 | | /* Encode the DC coefficient difference per section G.1.2.1 */ |
495 | | |
496 | | /* This is a well-known technique for obtaining the absolute value without |
497 | | * a branch. It is derived from an assembly language technique presented |
498 | | * in "How to Optimize for the Pentium Processors", Copyright (c) 1996, |
499 | | * 1997 by Agner Fog. |
500 | | */ |
501 | 0 | temp3 = temp >> (CHAR_BIT * sizeof(int) - 1); |
502 | 0 | temp ^= temp3; |
503 | 0 | temp -= temp3; /* temp is abs value of input */ |
504 | | /* For a negative input, want temp2 = bitwise complement of abs(input) */ |
505 | 0 | temp2 = temp ^ temp3; |
506 | | |
507 | | /* Find the number of bits needed for the magnitude of the coefficient */ |
508 | 0 | nbits = JPEG_NBITS(temp); |
509 | | /* Check for out-of-range coefficient values. |
510 | | * Since we're encoding a difference, the range limit is twice as much. |
511 | | */ |
512 | 0 | if (nbits > max_coef_bits + 1) |
513 | 0 | ERREXIT(cinfo, JERR_BAD_DCT_COEF); |
514 | | |
515 | | /* Count/emit the Huffman-coded symbol for the number of bits */ |
516 | 0 | emit_symbol(entropy, compptr->dc_tbl_no, nbits); |
517 | | |
518 | | /* Emit that number of bits of the value, if positive, */ |
519 | | /* or the complement of its magnitude, if negative. */ |
520 | 0 | if (nbits) /* emit_bits rejects calls with size 0 */ |
521 | 0 | emit_bits(entropy, (unsigned int)temp2, nbits); |
522 | 0 | } |
523 | |
|
524 | 0 | cinfo->dest->next_output_byte = entropy->next_output_byte; |
525 | 0 | cinfo->dest->free_in_buffer = entropy->free_in_buffer; |
526 | | |
527 | | /* Update restart-interval state too */ |
528 | 0 | if (cinfo->restart_interval) { |
529 | 0 | if (entropy->restarts_to_go == 0) { |
530 | 0 | entropy->restarts_to_go = cinfo->restart_interval; |
531 | 0 | entropy->next_restart_num++; |
532 | 0 | entropy->next_restart_num &= 7; |
533 | 0 | } |
534 | 0 | entropy->restarts_to_go--; |
535 | 0 | } |
536 | |
|
537 | 0 | return TRUE; |
538 | 0 | } |
539 | | |
540 | | |
541 | | /* |
542 | | * Data preparation for encode_mcu_AC_first(). |
543 | | */ |
544 | | |
545 | 0 | #define COMPUTE_ABSVALUES_AC_FIRST(Sl) { \ |
546 | 0 | for (k = 0; k < Sl; k++) { \ |
547 | 0 | temp = block[jpeg_natural_order_start[k]]; \ |
548 | 0 | if (temp == 0) \ |
549 | 0 | continue; \ |
550 | 0 | /* We must apply the point transform by Al. For AC coefficients this \ |
551 | 0 | * is an integer division with rounding towards 0. To do this portably \ |
552 | 0 | * in C, we shift after obtaining the absolute value; so the code is \ |
553 | 0 | * interwoven with finding the abs value (temp) and output bits (temp2). \ |
554 | 0 | */ \ |
555 | 0 | temp2 = temp >> (CHAR_BIT * sizeof(int) - 1); \ |
556 | 0 | temp ^= temp2; \ |
557 | 0 | temp -= temp2; /* temp is abs value of input */ \ |
558 | 0 | temp >>= Al; /* apply the point transform */ \ |
559 | 0 | /* Watch out for case that nonzero coef is zero after point transform */ \ |
560 | 0 | if (temp == 0) \ |
561 | 0 | continue; \ |
562 | 0 | /* For a negative coef, want temp2 = bitwise complement of abs(coef) */ \ |
563 | 0 | temp2 ^= temp; \ |
564 | 0 | values[k] = (UJCOEF)temp; \ |
565 | 0 | values[k + DCTSIZE2] = (UJCOEF)temp2; \ |
566 | 0 | zerobits |= ((size_t)1U) << k; \ |
567 | 0 | } \ |
568 | 0 | } |
569 | | |
570 | | METHODDEF(void) |
571 | | encode_mcu_AC_first_prepare(const JCOEF *block, |
572 | | const int *jpeg_natural_order_start, int Sl, |
573 | | int Al, UJCOEF *values, size_t *bits) |
574 | 0 | { |
575 | 0 | register int k, temp, temp2; |
576 | 0 | size_t zerobits = 0U; |
577 | 0 | int Sl0 = Sl; |
578 | |
|
579 | | #if SIZEOF_SIZE_T == 4 |
580 | | if (Sl0 > 32) |
581 | | Sl0 = 32; |
582 | | #endif |
583 | |
|
584 | 0 | COMPUTE_ABSVALUES_AC_FIRST(Sl0); |
585 | |
|
586 | 0 | bits[0] = zerobits; |
587 | | #if SIZEOF_SIZE_T == 4 |
588 | | zerobits = 0U; |
589 | | |
590 | | if (Sl > 32) { |
591 | | Sl -= 32; |
592 | | jpeg_natural_order_start += 32; |
593 | | values += 32; |
594 | | |
595 | | COMPUTE_ABSVALUES_AC_FIRST(Sl); |
596 | | } |
597 | | bits[1] = zerobits; |
598 | | #endif |
599 | 0 | } |
600 | | |
601 | | /* |
602 | | * MCU encoding for AC initial scan (either spectral selection, |
603 | | * or first pass of successive approximation). |
604 | | */ |
605 | | |
606 | 0 | #define ENCODE_COEFS_AC_FIRST(label) { \ |
607 | 0 | while (zerobits) { \ |
608 | 0 | r = count_zeroes(&zerobits); \ |
609 | 0 | cvalue += r; \ |
610 | 0 | label \ |
611 | 0 | temp = cvalue[0]; \ |
612 | 0 | temp2 = cvalue[DCTSIZE2]; \ |
613 | 0 | \ |
614 | 0 | /* if run length > 15, must emit special run-length-16 codes (0xF0) */ \ |
615 | 0 | while (r > 15) { \ |
616 | 0 | emit_symbol(entropy, entropy->ac_tbl_no, 0xF0); \ |
617 | 0 | r -= 16; \ |
618 | 0 | } \ |
619 | 0 | \ |
620 | 0 | /* Find the number of bits needed for the magnitude of the coefficient */ \ |
621 | 0 | nbits = JPEG_NBITS_NONZERO(temp); /* there must be at least one 1 bit */ \ |
622 | 0 | /* Check for out-of-range coefficient values */ \ |
623 | 0 | if (nbits > max_coef_bits) \ |
624 | 0 | ERREXIT(cinfo, JERR_BAD_DCT_COEF); \ |
625 | 0 | \ |
626 | 0 | /* Count/emit Huffman symbol for run length / number of bits */ \ |
627 | 0 | emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + nbits); \ |
628 | 0 | \ |
629 | 0 | /* Emit that number of bits of the value, if positive, */ \ |
630 | 0 | /* or the complement of its magnitude, if negative. */ \ |
631 | 0 | emit_bits(entropy, (unsigned int)temp2, nbits); \ |
632 | 0 | \ |
633 | 0 | cvalue++; \ |
634 | 0 | zerobits >>= 1; \ |
635 | 0 | } \ |
636 | 0 | } |
637 | | |
638 | | METHODDEF(boolean) |
639 | | encode_mcu_AC_first(j_compress_ptr cinfo, JBLOCKROW *MCU_data) |
640 | 0 | { |
641 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
642 | 0 | register int temp, temp2; |
643 | 0 | register int nbits, r; |
644 | 0 | int Sl = cinfo->Se - cinfo->Ss + 1; |
645 | 0 | int Al = cinfo->Al; |
646 | 0 | UJCOEF values_unaligned[2 * DCTSIZE2 + 15]; |
647 | 0 | UJCOEF *values; |
648 | 0 | const UJCOEF *cvalue; |
649 | 0 | size_t zerobits; |
650 | 0 | size_t bits[8 / SIZEOF_SIZE_T]; |
651 | 0 | int max_coef_bits = cinfo->data_precision + 2; |
652 | |
|
653 | | #ifdef ZERO_BUFFERS |
654 | | memset(values_unaligned, 0, sizeof(values_unaligned)); |
655 | | memset(bits, 0, sizeof(bits)); |
656 | | #endif |
657 | |
|
658 | 0 | entropy->next_output_byte = cinfo->dest->next_output_byte; |
659 | 0 | entropy->free_in_buffer = cinfo->dest->free_in_buffer; |
660 | | |
661 | | /* Emit restart marker if needed */ |
662 | 0 | if (cinfo->restart_interval) |
663 | 0 | if (entropy->restarts_to_go == 0) |
664 | 0 | emit_restart(entropy, entropy->next_restart_num); |
665 | |
|
666 | 0 | #ifdef WITH_SIMD |
667 | 0 | cvalue = values = (UJCOEF *)PAD((JUINTPTR)values_unaligned, 16); |
668 | | #else |
669 | | /* Not using SIMD, so alignment is not needed */ |
670 | | cvalue = values = values_unaligned; |
671 | | #endif |
672 | | |
673 | | /* Prepare data */ |
674 | 0 | entropy->AC_first_prepare(MCU_data[0][0], jpeg_natural_order + cinfo->Ss, |
675 | 0 | Sl, Al, values, bits); |
676 | |
|
677 | 0 | zerobits = bits[0]; |
678 | | #if SIZEOF_SIZE_T == 4 |
679 | | zerobits |= bits[1]; |
680 | | #endif |
681 | | |
682 | | /* Emit any pending EOBRUN */ |
683 | 0 | if (zerobits && (entropy->EOBRUN > 0)) |
684 | 0 | emit_eobrun(entropy); |
685 | |
|
686 | | #if SIZEOF_SIZE_T == 4 |
687 | | zerobits = bits[0]; |
688 | | #endif |
689 | | |
690 | | /* Encode the AC coefficients per section G.1.2.2, fig. G.3 */ |
691 | |
|
692 | 0 | ENCODE_COEFS_AC_FIRST((void)0;); |
693 | |
|
694 | | #if SIZEOF_SIZE_T == 4 |
695 | | zerobits = bits[1]; |
696 | | if (zerobits) { |
697 | | int diff = ((values + DCTSIZE2 / 2) - cvalue); |
698 | | r = count_zeroes(&zerobits); |
699 | | r += diff; |
700 | | cvalue += r; |
701 | | goto first_iter_ac_first; |
702 | | } |
703 | | |
704 | | ENCODE_COEFS_AC_FIRST(first_iter_ac_first:); |
705 | | #endif |
706 | |
|
707 | 0 | if (cvalue < (values + Sl)) { /* If there are trailing zeroes, */ |
708 | 0 | entropy->EOBRUN++; /* count an EOB */ |
709 | 0 | if (entropy->EOBRUN == 0x7FFF) |
710 | 0 | emit_eobrun(entropy); /* force it out to avoid overflow */ |
711 | 0 | } |
712 | |
|
713 | 0 | cinfo->dest->next_output_byte = entropy->next_output_byte; |
714 | 0 | cinfo->dest->free_in_buffer = entropy->free_in_buffer; |
715 | | |
716 | | /* Update restart-interval state too */ |
717 | 0 | if (cinfo->restart_interval) { |
718 | 0 | if (entropy->restarts_to_go == 0) { |
719 | 0 | entropy->restarts_to_go = cinfo->restart_interval; |
720 | 0 | entropy->next_restart_num++; |
721 | 0 | entropy->next_restart_num &= 7; |
722 | 0 | } |
723 | 0 | entropy->restarts_to_go--; |
724 | 0 | } |
725 | |
|
726 | 0 | return TRUE; |
727 | 0 | } |
728 | | |
729 | | |
730 | | /* |
731 | | * MCU encoding for DC successive approximation refinement scan. |
732 | | * Note: we assume such scans can be multi-component, although the spec |
733 | | * is not very clear on the point. |
734 | | */ |
735 | | |
736 | | METHODDEF(boolean) |
737 | | encode_mcu_DC_refine(j_compress_ptr cinfo, JBLOCKROW *MCU_data) |
738 | 0 | { |
739 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
740 | 0 | register int temp; |
741 | 0 | int blkn; |
742 | 0 | int Al = cinfo->Al; |
743 | 0 | JBLOCKROW block; |
744 | |
|
745 | 0 | entropy->next_output_byte = cinfo->dest->next_output_byte; |
746 | 0 | entropy->free_in_buffer = cinfo->dest->free_in_buffer; |
747 | | |
748 | | /* Emit restart marker if needed */ |
749 | 0 | if (cinfo->restart_interval) |
750 | 0 | if (entropy->restarts_to_go == 0) |
751 | 0 | emit_restart(entropy, entropy->next_restart_num); |
752 | | |
753 | | /* Encode the MCU data blocks */ |
754 | 0 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { |
755 | 0 | block = MCU_data[blkn]; |
756 | | |
757 | | /* We simply emit the Al'th bit of the DC coefficient value. */ |
758 | 0 | temp = (*block)[0]; |
759 | 0 | emit_bits(entropy, (unsigned int)(temp >> Al), 1); |
760 | 0 | } |
761 | |
|
762 | 0 | cinfo->dest->next_output_byte = entropy->next_output_byte; |
763 | 0 | cinfo->dest->free_in_buffer = entropy->free_in_buffer; |
764 | | |
765 | | /* Update restart-interval state too */ |
766 | 0 | if (cinfo->restart_interval) { |
767 | 0 | if (entropy->restarts_to_go == 0) { |
768 | 0 | entropy->restarts_to_go = cinfo->restart_interval; |
769 | 0 | entropy->next_restart_num++; |
770 | 0 | entropy->next_restart_num &= 7; |
771 | 0 | } |
772 | 0 | entropy->restarts_to_go--; |
773 | 0 | } |
774 | |
|
775 | 0 | return TRUE; |
776 | 0 | } |
777 | | |
778 | | |
779 | | /* |
780 | | * Data preparation for encode_mcu_AC_refine(). |
781 | | */ |
782 | | |
783 | 0 | #define COMPUTE_ABSVALUES_AC_REFINE(Sl, koffset) { \ |
784 | 0 | /* It is convenient to make a pre-pass to determine the transformed \ |
785 | 0 | * coefficients' absolute values and the EOB position. \ |
786 | 0 | */ \ |
787 | 0 | for (k = 0; k < Sl; k++) { \ |
788 | 0 | temp = block[jpeg_natural_order_start[k]]; \ |
789 | 0 | /* We must apply the point transform by Al. For AC coefficients this \ |
790 | 0 | * is an integer division with rounding towards 0. To do this portably \ |
791 | 0 | * in C, we shift after obtaining the absolute value. \ |
792 | 0 | */ \ |
793 | 0 | temp2 = temp >> (CHAR_BIT * sizeof(int) - 1); \ |
794 | 0 | temp ^= temp2; \ |
795 | 0 | temp -= temp2; /* temp is abs value of input */ \ |
796 | 0 | temp >>= Al; /* apply the point transform */ \ |
797 | 0 | if (temp != 0) { \ |
798 | 0 | zerobits |= ((size_t)1U) << k; \ |
799 | 0 | signbits |= ((size_t)(temp2 + 1)) << k; \ |
800 | 0 | } \ |
801 | 0 | absvalues[k] = (UJCOEF)temp; /* save abs value for main pass */ \ |
802 | 0 | if (temp == 1) \ |
803 | 0 | EOB = k + koffset; /* EOB = index of last newly-nonzero coef */ \ |
804 | 0 | } \ |
805 | 0 | } |
806 | | |
807 | | METHODDEF(int) |
808 | | encode_mcu_AC_refine_prepare(const JCOEF *block, |
809 | | const int *jpeg_natural_order_start, int Sl, |
810 | | int Al, UJCOEF *absvalues, size_t *bits) |
811 | 0 | { |
812 | 0 | register int k, temp, temp2; |
813 | 0 | int EOB = 0; |
814 | 0 | size_t zerobits = 0U, signbits = 0U; |
815 | 0 | int Sl0 = Sl; |
816 | |
|
817 | | #if SIZEOF_SIZE_T == 4 |
818 | | if (Sl0 > 32) |
819 | | Sl0 = 32; |
820 | | #endif |
821 | |
|
822 | 0 | COMPUTE_ABSVALUES_AC_REFINE(Sl0, 0); |
823 | |
|
824 | 0 | bits[0] = zerobits; |
825 | 0 | #if SIZEOF_SIZE_T == 8 |
826 | 0 | bits[1] = signbits; |
827 | | #else |
828 | | bits[2] = signbits; |
829 | | |
830 | | zerobits = 0U; |
831 | | signbits = 0U; |
832 | | |
833 | | if (Sl > 32) { |
834 | | Sl -= 32; |
835 | | jpeg_natural_order_start += 32; |
836 | | absvalues += 32; |
837 | | |
838 | | COMPUTE_ABSVALUES_AC_REFINE(Sl, 32); |
839 | | } |
840 | | |
841 | | bits[1] = zerobits; |
842 | | bits[3] = signbits; |
843 | | #endif |
844 | |
|
845 | 0 | return EOB; |
846 | 0 | } |
847 | | |
848 | | |
849 | | /* |
850 | | * MCU encoding for AC successive approximation refinement scan. |
851 | | */ |
852 | | |
853 | 0 | #define ENCODE_COEFS_AC_REFINE(label) { \ |
854 | 0 | while (zerobits) { \ |
855 | 0 | idx = count_zeroes(&zerobits); \ |
856 | 0 | r += idx; \ |
857 | 0 | cabsvalue += idx; \ |
858 | 0 | signbits >>= idx; \ |
859 | 0 | label \ |
860 | 0 | /* Emit any required ZRLs, but not if they can be folded into EOB */ \ |
861 | 0 | while (r > 15 && (cabsvalue <= EOBPTR)) { \ |
862 | 0 | /* emit any pending EOBRUN and the BE correction bits */ \ |
863 | 0 | emit_eobrun(entropy); \ |
864 | 0 | /* Emit ZRL */ \ |
865 | 0 | emit_symbol(entropy, entropy->ac_tbl_no, 0xF0); \ |
866 | 0 | r -= 16; \ |
867 | 0 | /* Emit buffered correction bits that must be associated with ZRL */ \ |
868 | 0 | emit_buffered_bits(entropy, BR_buffer, BR); \ |
869 | 0 | BR_buffer = entropy->bit_buffer; /* BE bits are gone now */ \ |
870 | 0 | BR = 0; \ |
871 | 0 | } \ |
872 | 0 | \ |
873 | 0 | temp = *cabsvalue++; \ |
874 | 0 | \ |
875 | 0 | /* If the coef was previously nonzero, it only needs a correction bit. \ |
876 | 0 | * NOTE: a straight translation of the spec's figure G.7 would suggest \ |
877 | 0 | * that we also need to test r > 15. But if r > 15, we can only get here \ |
878 | 0 | * if k > EOB, which implies that this coefficient is not 1. \ |
879 | 0 | */ \ |
880 | 0 | if (temp > 1) { \ |
881 | 0 | /* The correction bit is the next bit of the absolute value. */ \ |
882 | 0 | BR_buffer[BR++] = (char)(temp & 1); \ |
883 | 0 | signbits >>= 1; \ |
884 | 0 | zerobits >>= 1; \ |
885 | 0 | continue; \ |
886 | 0 | } \ |
887 | 0 | \ |
888 | 0 | /* Emit any pending EOBRUN and the BE correction bits */ \ |
889 | 0 | emit_eobrun(entropy); \ |
890 | 0 | \ |
891 | 0 | /* Count/emit Huffman symbol for run length / number of bits */ \ |
892 | 0 | emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1); \ |
893 | 0 | \ |
894 | 0 | /* Emit output bit for newly-nonzero coef */ \ |
895 | 0 | temp = signbits & 1; /* ((*block)[jpeg_natural_order_start[k]] < 0) ? 0 : 1 */ \ |
896 | 0 | emit_bits(entropy, (unsigned int)temp, 1); \ |
897 | 0 | \ |
898 | 0 | /* Emit buffered correction bits that must be associated with this code */ \ |
899 | 0 | emit_buffered_bits(entropy, BR_buffer, BR); \ |
900 | 0 | BR_buffer = entropy->bit_buffer; /* BE bits are gone now */ \ |
901 | 0 | BR = 0; \ |
902 | 0 | r = 0; /* reset zero run length */ \ |
903 | 0 | signbits >>= 1; \ |
904 | 0 | zerobits >>= 1; \ |
905 | 0 | } \ |
906 | 0 | } |
907 | | |
908 | | METHODDEF(boolean) |
909 | | encode_mcu_AC_refine(j_compress_ptr cinfo, JBLOCKROW *MCU_data) |
910 | 0 | { |
911 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
912 | 0 | register int temp, r, idx; |
913 | 0 | char *BR_buffer; |
914 | 0 | unsigned int BR; |
915 | 0 | int Sl = cinfo->Se - cinfo->Ss + 1; |
916 | 0 | int Al = cinfo->Al; |
917 | 0 | UJCOEF absvalues_unaligned[DCTSIZE2 + 15]; |
918 | 0 | UJCOEF *absvalues; |
919 | 0 | const UJCOEF *cabsvalue, *EOBPTR; |
920 | 0 | size_t zerobits, signbits; |
921 | 0 | size_t bits[16 / SIZEOF_SIZE_T]; |
922 | |
|
923 | | #ifdef ZERO_BUFFERS |
924 | | memset(absvalues_unaligned, 0, sizeof(absvalues_unaligned)); |
925 | | memset(bits, 0, sizeof(bits)); |
926 | | #endif |
927 | |
|
928 | 0 | entropy->next_output_byte = cinfo->dest->next_output_byte; |
929 | 0 | entropy->free_in_buffer = cinfo->dest->free_in_buffer; |
930 | | |
931 | | /* Emit restart marker if needed */ |
932 | 0 | if (cinfo->restart_interval) |
933 | 0 | if (entropy->restarts_to_go == 0) |
934 | 0 | emit_restart(entropy, entropy->next_restart_num); |
935 | |
|
936 | 0 | #ifdef WITH_SIMD |
937 | 0 | cabsvalue = absvalues = (UJCOEF *)PAD((JUINTPTR)absvalues_unaligned, 16); |
938 | | #else |
939 | | /* Not using SIMD, so alignment is not needed */ |
940 | | cabsvalue = absvalues = absvalues_unaligned; |
941 | | #endif |
942 | | |
943 | | /* Prepare data */ |
944 | 0 | EOBPTR = absvalues + |
945 | 0 | entropy->AC_refine_prepare(MCU_data[0][0], jpeg_natural_order + cinfo->Ss, |
946 | 0 | Sl, Al, absvalues, bits); |
947 | | |
948 | | /* Encode the AC coefficients per section G.1.2.3, fig. G.7 */ |
949 | |
|
950 | 0 | r = 0; /* r = run length of zeros */ |
951 | 0 | BR = 0; /* BR = count of buffered bits added now */ |
952 | 0 | BR_buffer = entropy->bit_buffer + entropy->BE; /* Append bits to buffer */ |
953 | |
|
954 | 0 | zerobits = bits[0]; |
955 | 0 | #if SIZEOF_SIZE_T == 8 |
956 | 0 | signbits = bits[1]; |
957 | | #else |
958 | | signbits = bits[2]; |
959 | | #endif |
960 | 0 | ENCODE_COEFS_AC_REFINE((void)0;); |
961 | |
|
962 | | #if SIZEOF_SIZE_T == 4 |
963 | | zerobits = bits[1]; |
964 | | signbits = bits[3]; |
965 | | |
966 | | if (zerobits) { |
967 | | int diff = ((absvalues + DCTSIZE2 / 2) - cabsvalue); |
968 | | idx = count_zeroes(&zerobits); |
969 | | signbits >>= idx; |
970 | | idx += diff; |
971 | | r += idx; |
972 | | cabsvalue += idx; |
973 | | goto first_iter_ac_refine; |
974 | | } |
975 | | |
976 | | ENCODE_COEFS_AC_REFINE(first_iter_ac_refine:); |
977 | | #endif |
978 | |
|
979 | 0 | r |= (int)((absvalues + Sl) - cabsvalue); |
980 | |
|
981 | 0 | if (r > 0 || BR > 0) { /* If there are trailing zeroes, */ |
982 | 0 | entropy->EOBRUN++; /* count an EOB */ |
983 | 0 | entropy->BE += BR; /* concat my correction bits to older ones */ |
984 | | /* We force out the EOB if we risk either: |
985 | | * 1. overflow of the EOB counter; |
986 | | * 2. overflow of the correction bit buffer during the next MCU. |
987 | | */ |
988 | 0 | if (entropy->EOBRUN == 0x7FFF || |
989 | 0 | entropy->BE > (MAX_CORR_BITS - DCTSIZE2 + 1)) |
990 | 0 | emit_eobrun(entropy); |
991 | 0 | } |
992 | |
|
993 | 0 | cinfo->dest->next_output_byte = entropy->next_output_byte; |
994 | 0 | cinfo->dest->free_in_buffer = entropy->free_in_buffer; |
995 | | |
996 | | /* Update restart-interval state too */ |
997 | 0 | if (cinfo->restart_interval) { |
998 | 0 | if (entropy->restarts_to_go == 0) { |
999 | 0 | entropy->restarts_to_go = cinfo->restart_interval; |
1000 | 0 | entropy->next_restart_num++; |
1001 | 0 | entropy->next_restart_num &= 7; |
1002 | 0 | } |
1003 | 0 | entropy->restarts_to_go--; |
1004 | 0 | } |
1005 | |
|
1006 | 0 | return TRUE; |
1007 | 0 | } |
1008 | | |
1009 | | |
1010 | | /* |
1011 | | * Finish up at the end of a Huffman-compressed progressive scan. |
1012 | | */ |
1013 | | |
1014 | | METHODDEF(void) |
1015 | | finish_pass_phuff(j_compress_ptr cinfo) |
1016 | 0 | { |
1017 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
1018 | |
|
1019 | 0 | entropy->next_output_byte = cinfo->dest->next_output_byte; |
1020 | 0 | entropy->free_in_buffer = cinfo->dest->free_in_buffer; |
1021 | | |
1022 | | /* Flush out any buffered data */ |
1023 | 0 | emit_eobrun(entropy); |
1024 | 0 | flush_bits(entropy); |
1025 | |
|
1026 | 0 | cinfo->dest->next_output_byte = entropy->next_output_byte; |
1027 | 0 | cinfo->dest->free_in_buffer = entropy->free_in_buffer; |
1028 | 0 | } |
1029 | | |
1030 | | |
1031 | | /* |
1032 | | * Finish up a statistics-gathering pass and create the new Huffman tables. |
1033 | | */ |
1034 | | |
1035 | | METHODDEF(void) |
1036 | | finish_pass_gather_phuff(j_compress_ptr cinfo) |
1037 | 0 | { |
1038 | 0 | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
1039 | 0 | boolean is_DC_band; |
1040 | 0 | int ci, tbl; |
1041 | 0 | jpeg_component_info *compptr; |
1042 | 0 | JHUFF_TBL **htblptr; |
1043 | 0 | boolean did[NUM_HUFF_TBLS]; |
1044 | | |
1045 | | /* Flush out buffered data (all we care about is counting the EOB symbol) */ |
1046 | 0 | emit_eobrun(entropy); |
1047 | |
|
1048 | 0 | is_DC_band = (cinfo->Ss == 0); |
1049 | | |
1050 | | /* It's important not to apply jpeg_gen_optimal_table more than once |
1051 | | * per table, because it clobbers the input frequency counts! |
1052 | | */ |
1053 | 0 | memset(did, 0, sizeof(did)); |
1054 | |
|
1055 | 0 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
1056 | 0 | compptr = cinfo->cur_comp_info[ci]; |
1057 | 0 | if (is_DC_band) { |
1058 | 0 | if (cinfo->Ah != 0) /* DC refinement needs no table */ |
1059 | 0 | continue; |
1060 | 0 | tbl = compptr->dc_tbl_no; |
1061 | 0 | } else { |
1062 | 0 | tbl = compptr->ac_tbl_no; |
1063 | 0 | } |
1064 | 0 | if (!did[tbl]) { |
1065 | 0 | if (is_DC_band) |
1066 | 0 | htblptr = &cinfo->dc_huff_tbl_ptrs[tbl]; |
1067 | 0 | else |
1068 | 0 | htblptr = &cinfo->ac_huff_tbl_ptrs[tbl]; |
1069 | 0 | if (*htblptr == NULL) |
1070 | 0 | *htblptr = jpeg_alloc_huff_table((j_common_ptr)cinfo); |
1071 | 0 | jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[tbl]); |
1072 | 0 | did[tbl] = TRUE; |
1073 | 0 | } |
1074 | 0 | } |
1075 | 0 | } |
1076 | | |
1077 | | |
1078 | | /* |
1079 | | * Module initialization routine for progressive Huffman entropy encoding. |
1080 | | */ |
1081 | | |
1082 | | GLOBAL(void) |
1083 | | jinit_phuff_encoder(j_compress_ptr cinfo) |
1084 | 0 | { |
1085 | 0 | phuff_entropy_ptr entropy; |
1086 | 0 | int i; |
1087 | |
|
1088 | 0 | entropy = (phuff_entropy_ptr) |
1089 | 0 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
1090 | 0 | sizeof(phuff_entropy_encoder)); |
1091 | 0 | cinfo->entropy = (struct jpeg_entropy_encoder *)entropy; |
1092 | 0 | entropy->pub.start_pass = start_pass_phuff; |
1093 | | |
1094 | | /* Mark tables unallocated */ |
1095 | 0 | for (i = 0; i < NUM_HUFF_TBLS; i++) { |
1096 | 0 | entropy->derived_tbls[i] = NULL; |
1097 | 0 | entropy->count_ptrs[i] = NULL; |
1098 | 0 | } |
1099 | 0 | entropy->bit_buffer = NULL; /* needed only in AC refinement scan */ |
1100 | 0 | } |
1101 | | |
1102 | | #endif /* C_PROGRESSIVE_SUPPORTED */ |