/src/libjpeg-turbo.main/jdphuff.c
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1 | | /* |
2 | | * jdphuff.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) 2015-2016, 2018-2022, D. R. Commander. |
10 | | * For conditions of distribution and use, see the accompanying README.ijg |
11 | | * file. |
12 | | * |
13 | | * This file contains Huffman entropy decoding routines for progressive JPEG. |
14 | | * |
15 | | * Much of the complexity here has to do with supporting input suspension. |
16 | | * If the data source module demands suspension, we want to be able to back |
17 | | * up to the start of the current MCU. To do this, we copy state variables |
18 | | * into local working storage, and update them back to the permanent |
19 | | * storage only upon successful completion of an MCU. |
20 | | * |
21 | | * NOTE: All referenced figures are from |
22 | | * Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994. |
23 | | */ |
24 | | |
25 | | #define JPEG_INTERNALS |
26 | | #include "jinclude.h" |
27 | | #include "jpeglib.h" |
28 | | #include "jdhuff.h" /* Declarations shared with jd*huff.c */ |
29 | | #include <limits.h> |
30 | | |
31 | | |
32 | | #ifdef D_PROGRESSIVE_SUPPORTED |
33 | | |
34 | | /* |
35 | | * Expanded entropy decoder object for progressive Huffman decoding. |
36 | | * |
37 | | * The savable_state subrecord contains fields that change within an MCU, |
38 | | * but must not be updated permanently until we complete the MCU. |
39 | | */ |
40 | | |
41 | | typedef struct { |
42 | | unsigned int EOBRUN; /* remaining EOBs in EOBRUN */ |
43 | | int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */ |
44 | | } savable_state; |
45 | | |
46 | | typedef struct { |
47 | | struct jpeg_entropy_decoder pub; /* public fields */ |
48 | | |
49 | | /* These fields are loaded into local variables at start of each MCU. |
50 | | * In case of suspension, we exit WITHOUT updating them. |
51 | | */ |
52 | | bitread_perm_state bitstate; /* Bit buffer at start of MCU */ |
53 | | savable_state saved; /* Other state at start of MCU */ |
54 | | |
55 | | /* These fields are NOT loaded into local working state. */ |
56 | | unsigned int restarts_to_go; /* MCUs left in this restart interval */ |
57 | | |
58 | | /* Pointers to derived tables (these workspaces have image lifespan) */ |
59 | | d_derived_tbl *derived_tbls[NUM_HUFF_TBLS]; |
60 | | |
61 | | d_derived_tbl *ac_derived_tbl; /* active table during an AC scan */ |
62 | | } phuff_entropy_decoder; |
63 | | |
64 | | typedef phuff_entropy_decoder *phuff_entropy_ptr; |
65 | | |
66 | | /* Forward declarations */ |
67 | | METHODDEF(boolean) decode_mcu_DC_first(j_decompress_ptr cinfo, |
68 | | JBLOCKROW *MCU_data); |
69 | | METHODDEF(boolean) decode_mcu_AC_first(j_decompress_ptr cinfo, |
70 | | JBLOCKROW *MCU_data); |
71 | | METHODDEF(boolean) decode_mcu_DC_refine(j_decompress_ptr cinfo, |
72 | | JBLOCKROW *MCU_data); |
73 | | METHODDEF(boolean) decode_mcu_AC_refine(j_decompress_ptr cinfo, |
74 | | JBLOCKROW *MCU_data); |
75 | | |
76 | | |
77 | | /* |
78 | | * Initialize for a Huffman-compressed scan. |
79 | | */ |
80 | | |
81 | | METHODDEF(void) |
82 | | start_pass_phuff_decoder(j_decompress_ptr cinfo) |
83 | 103k | { |
84 | 103k | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
85 | 103k | boolean is_DC_band, bad; |
86 | 103k | int ci, coefi, tbl; |
87 | 103k | d_derived_tbl **pdtbl; |
88 | 103k | int *coef_bit_ptr, *prev_coef_bit_ptr; |
89 | 103k | jpeg_component_info *compptr; |
90 | | |
91 | 103k | is_DC_band = (cinfo->Ss == 0); |
92 | | |
93 | | /* Validate scan parameters */ |
94 | 103k | bad = FALSE; |
95 | 103k | if (is_DC_band) { |
96 | 20.6k | if (cinfo->Se != 0) |
97 | 183 | bad = TRUE; |
98 | 83.0k | } else { |
99 | | /* need not check Ss/Se < 0 since they came from unsigned bytes */ |
100 | 83.0k | if (cinfo->Ss > cinfo->Se || cinfo->Se >= DCTSIZE2) |
101 | 313 | bad = TRUE; |
102 | | /* AC scans may have only one component */ |
103 | 83.0k | if (cinfo->comps_in_scan != 1) |
104 | 48 | bad = TRUE; |
105 | 83.0k | } |
106 | 103k | if (cinfo->Ah != 0) { |
107 | | /* Successive approximation refinement scan: must have Al = Ah-1. */ |
108 | 72.3k | if (cinfo->Al != cinfo->Ah - 1) |
109 | 311 | bad = TRUE; |
110 | 72.3k | } |
111 | 103k | if (cinfo->Al > 13) /* need not check for < 0 */ |
112 | 56 | bad = TRUE; |
113 | | /* Arguably the maximum Al value should be less than 13 for 8-bit precision, |
114 | | * but the spec doesn't say so, and we try to be liberal about what we |
115 | | * accept. Note: large Al values could result in out-of-range DC |
116 | | * coefficients during early scans, leading to bizarre displays due to |
117 | | * overflows in the IDCT math. But we won't crash. |
118 | | */ |
119 | 103k | if (bad) |
120 | 552 | ERREXIT4(cinfo, JERR_BAD_PROGRESSION, |
121 | 103k | cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al); |
122 | | /* Update progression status, and verify that scan order is legal. |
123 | | * Note that inter-scan inconsistencies are treated as warnings |
124 | | * not fatal errors ... not clear if this is right way to behave. |
125 | | */ |
126 | 225k | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
127 | 122k | int cindex = cinfo->cur_comp_info[ci]->component_index; |
128 | 122k | coef_bit_ptr = &cinfo->coef_bits[cindex][0]; |
129 | 122k | prev_coef_bit_ptr = &cinfo->coef_bits[cindex + cinfo->num_components][0]; |
130 | 122k | if (!is_DC_band && coef_bit_ptr[0] < 0) /* AC without prior DC scan */ |
131 | 75.0k | WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, 0); |
132 | 4.03M | for (coefi = MIN(cinfo->Ss, 1); coefi <= MAX(cinfo->Se, 9); coefi++) { |
133 | 3.91M | if (cinfo->input_scan_number > 1) |
134 | 3.65M | prev_coef_bit_ptr[coefi] = coef_bit_ptr[coefi]; |
135 | 265k | else |
136 | 265k | prev_coef_bit_ptr[coefi] = 0; |
137 | 3.91M | } |
138 | 2.50M | for (coefi = cinfo->Ss; coefi <= cinfo->Se; coefi++) { |
139 | 2.38M | int expected = (coef_bit_ptr[coefi] < 0) ? 0 : coef_bit_ptr[coefi]; |
140 | 2.38M | if (cinfo->Ah != expected) |
141 | 1.79M | WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, coefi); |
142 | 2.38M | coef_bit_ptr[coefi] = cinfo->Al; |
143 | 2.38M | } |
144 | 122k | } |
145 | | |
146 | | /* Select MCU decoding routine */ |
147 | 103k | if (cinfo->Ah == 0) { |
148 | 31.0k | if (is_DC_band) |
149 | 12.8k | entropy->pub.decode_mcu = decode_mcu_DC_first; |
150 | 18.2k | else |
151 | 18.2k | entropy->pub.decode_mcu = decode_mcu_AC_first; |
152 | 72.6k | } else { |
153 | 72.6k | if (is_DC_band) |
154 | 7.58k | entropy->pub.decode_mcu = decode_mcu_DC_refine; |
155 | 65.0k | else |
156 | 65.0k | entropy->pub.decode_mcu = decode_mcu_AC_refine; |
157 | 72.6k | } |
158 | | |
159 | 225k | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
160 | 122k | compptr = cinfo->cur_comp_info[ci]; |
161 | | /* Make sure requested tables are present, and compute derived tables. |
162 | | * We may build same derived table more than once, but it's not expensive. |
163 | | */ |
164 | 122k | if (is_DC_band) { |
165 | 39.3k | if (cinfo->Ah == 0) { /* DC refinement needs no table */ |
166 | 30.1k | tbl = compptr->dc_tbl_no; |
167 | 30.1k | pdtbl = (d_derived_tbl **)(entropy->derived_tbls) + tbl; |
168 | 30.1k | jpeg_make_d_derived_tbl(cinfo, TRUE, tbl, pdtbl); |
169 | 30.1k | } |
170 | 82.7k | } else { |
171 | 82.7k | tbl = compptr->ac_tbl_no; |
172 | 82.7k | pdtbl = (d_derived_tbl **)(entropy->derived_tbls) + tbl; |
173 | 82.7k | jpeg_make_d_derived_tbl(cinfo, FALSE, tbl, pdtbl); |
174 | | /* remember the single active table */ |
175 | 82.7k | entropy->ac_derived_tbl = entropy->derived_tbls[tbl]; |
176 | 82.7k | } |
177 | | /* Initialize DC predictions to 0 */ |
178 | 122k | entropy->saved.last_dc_val[ci] = 0; |
179 | 122k | } |
180 | | |
181 | | /* Initialize bitread state variables */ |
182 | 103k | entropy->bitstate.bits_left = 0; |
183 | 103k | entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */ |
184 | 103k | entropy->pub.insufficient_data = FALSE; |
185 | | |
186 | | /* Initialize private state variables */ |
187 | 103k | entropy->saved.EOBRUN = 0; |
188 | | |
189 | | /* Initialize restart counter */ |
190 | 103k | entropy->restarts_to_go = cinfo->restart_interval; |
191 | 103k | } |
192 | | |
193 | | |
194 | | /* |
195 | | * Figure F.12: extend sign bit. |
196 | | * On some machines, a shift and add will be faster than a table lookup. |
197 | | */ |
198 | | |
199 | | #define AVOID_TABLES |
200 | | #ifdef AVOID_TABLES |
201 | | |
202 | 10.1M | #define NEG_1 ((unsigned)-1) |
203 | | #define HUFF_EXTEND(x, s) \ |
204 | 1.42M | ((x) < (1 << ((s) - 1)) ? (x) + (((NEG_1) << (s)) + 1) : (x)) |
205 | | |
206 | | #else |
207 | | |
208 | | #define HUFF_EXTEND(x, s) \ |
209 | | ((x) < extend_test[s] ? (x) + extend_offset[s] : (x)) |
210 | | |
211 | | static const int extend_test[16] = { /* entry n is 2**(n-1) */ |
212 | | 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, |
213 | | 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 |
214 | | }; |
215 | | |
216 | | static const int extend_offset[16] = { /* entry n is (-1 << n) + 1 */ |
217 | | 0, ((-1) << 1) + 1, ((-1) << 2) + 1, ((-1) << 3) + 1, ((-1) << 4) + 1, |
218 | | ((-1) << 5) + 1, ((-1) << 6) + 1, ((-1) << 7) + 1, ((-1) << 8) + 1, |
219 | | ((-1) << 9) + 1, ((-1) << 10) + 1, ((-1) << 11) + 1, ((-1) << 12) + 1, |
220 | | ((-1) << 13) + 1, ((-1) << 14) + 1, ((-1) << 15) + 1 |
221 | | }; |
222 | | |
223 | | #endif /* AVOID_TABLES */ |
224 | | |
225 | | |
226 | | /* |
227 | | * Check for a restart marker & resynchronize decoder. |
228 | | * Returns FALSE if must suspend. |
229 | | */ |
230 | | |
231 | | LOCAL(boolean) |
232 | | process_restart(j_decompress_ptr cinfo) |
233 | 320k | { |
234 | 320k | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
235 | 320k | int ci; |
236 | | |
237 | | /* Throw away any unused bits remaining in bit buffer; */ |
238 | | /* include any full bytes in next_marker's count of discarded bytes */ |
239 | 320k | cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8; |
240 | 320k | entropy->bitstate.bits_left = 0; |
241 | | |
242 | | /* Advance past the RSTn marker */ |
243 | 320k | if (!(*cinfo->marker->read_restart_marker) (cinfo)) |
244 | 0 | return FALSE; |
245 | | |
246 | | /* Re-initialize DC predictions to 0 */ |
247 | 668k | for (ci = 0; ci < cinfo->comps_in_scan; ci++) |
248 | 348k | entropy->saved.last_dc_val[ci] = 0; |
249 | | /* Re-init EOB run count, too */ |
250 | 320k | entropy->saved.EOBRUN = 0; |
251 | | |
252 | | /* Reset restart counter */ |
253 | 320k | entropy->restarts_to_go = cinfo->restart_interval; |
254 | | |
255 | | /* Reset out-of-data flag, unless read_restart_marker left us smack up |
256 | | * against a marker. In that case we will end up treating the next data |
257 | | * segment as empty, and we can avoid producing bogus output pixels by |
258 | | * leaving the flag set. |
259 | | */ |
260 | 320k | if (cinfo->unread_marker == 0) |
261 | 32.9k | entropy->pub.insufficient_data = FALSE; |
262 | | |
263 | 320k | return TRUE; |
264 | 320k | } |
265 | | |
266 | | |
267 | | /* |
268 | | * Huffman MCU decoding. |
269 | | * Each of these routines decodes and returns one MCU's worth of |
270 | | * Huffman-compressed coefficients. |
271 | | * The coefficients are reordered from zigzag order into natural array order, |
272 | | * but are not dequantized. |
273 | | * |
274 | | * The i'th block of the MCU is stored into the block pointed to by |
275 | | * MCU_data[i]. WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER. |
276 | | * |
277 | | * We return FALSE if data source requested suspension. In that case no |
278 | | * changes have been made to permanent state. (Exception: some output |
279 | | * coefficients may already have been assigned. This is harmless for |
280 | | * spectral selection, since we'll just re-assign them on the next call. |
281 | | * Successive approximation AC refinement has to be more careful, however.) |
282 | | */ |
283 | | |
284 | | /* |
285 | | * MCU decoding for DC initial scan (either spectral selection, |
286 | | * or first pass of successive approximation). |
287 | | */ |
288 | | |
289 | | METHODDEF(boolean) |
290 | | decode_mcu_DC_first(j_decompress_ptr cinfo, JBLOCKROW *MCU_data) |
291 | 1.33M | { |
292 | 1.33M | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
293 | 1.33M | int Al = cinfo->Al; |
294 | 1.33M | register int s, r; |
295 | 1.33M | int blkn, ci; |
296 | 1.33M | JBLOCKROW block; |
297 | 1.33M | BITREAD_STATE_VARS; |
298 | 1.33M | savable_state state; |
299 | 1.33M | d_derived_tbl *tbl; |
300 | 1.33M | jpeg_component_info *compptr; |
301 | | |
302 | | /* Process restart marker if needed; may have to suspend */ |
303 | 1.33M | if (cinfo->restart_interval) { |
304 | 224k | if (entropy->restarts_to_go == 0) |
305 | 18.1k | if (!process_restart(cinfo)) |
306 | 0 | return FALSE; |
307 | 224k | } |
308 | | |
309 | | /* If we've run out of data, just leave the MCU set to zeroes. |
310 | | * This way, we return uniform gray for the remainder of the segment. |
311 | | */ |
312 | 1.33M | if (!entropy->pub.insufficient_data) { |
313 | | |
314 | | /* Load up working state */ |
315 | 148k | BITREAD_LOAD_STATE(cinfo, entropy->bitstate); |
316 | 148k | state = entropy->saved; |
317 | | |
318 | | /* Outer loop handles each block in the MCU */ |
319 | | |
320 | 570k | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { |
321 | 421k | block = MCU_data[blkn]; |
322 | 421k | ci = cinfo->MCU_membership[blkn]; |
323 | 421k | compptr = cinfo->cur_comp_info[ci]; |
324 | 421k | tbl = entropy->derived_tbls[compptr->dc_tbl_no]; |
325 | | |
326 | | /* Decode a single block's worth of coefficients */ |
327 | | |
328 | | /* Section F.2.2.1: decode the DC coefficient difference */ |
329 | 421k | HUFF_DECODE(s, br_state, tbl, return FALSE, label1); |
330 | 421k | if (s) { |
331 | 190k | CHECK_BIT_BUFFER(br_state, s, return FALSE); |
332 | 190k | r = GET_BITS(s); |
333 | 190k | s = HUFF_EXTEND(r, s); |
334 | 190k | } |
335 | | |
336 | | /* Convert DC difference to actual value, update last_dc_val */ |
337 | 421k | if ((state.last_dc_val[ci] >= 0 && |
338 | 421k | s > INT_MAX - state.last_dc_val[ci]) || |
339 | 421k | (state.last_dc_val[ci] < 0 && s < INT_MIN - state.last_dc_val[ci])) |
340 | 0 | ERREXIT(cinfo, JERR_BAD_DCT_COEF); |
341 | 421k | s += state.last_dc_val[ci]; |
342 | 421k | state.last_dc_val[ci] = s; |
343 | | /* Scale and output the coefficient (assumes jpeg_natural_order[0]=0) */ |
344 | 421k | (*block)[0] = (JCOEF)LEFT_SHIFT(s, Al); |
345 | 421k | } |
346 | | |
347 | | /* Completed MCU, so update state */ |
348 | 148k | BITREAD_SAVE_STATE(cinfo, entropy->bitstate); |
349 | 148k | entropy->saved = state; |
350 | 148k | } |
351 | | |
352 | | /* Account for restart interval (no-op if not using restarts) */ |
353 | 1.33M | if (cinfo->restart_interval) |
354 | 224k | entropy->restarts_to_go--; |
355 | | |
356 | 1.33M | return TRUE; |
357 | 1.33M | } |
358 | | |
359 | | |
360 | | /* |
361 | | * MCU decoding for AC initial scan (either spectral selection, |
362 | | * or first pass of successive approximation). |
363 | | */ |
364 | | |
365 | | METHODDEF(boolean) |
366 | | decode_mcu_AC_first(j_decompress_ptr cinfo, JBLOCKROW *MCU_data) |
367 | 3.12M | { |
368 | 3.12M | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
369 | 3.12M | int Se = cinfo->Se; |
370 | 3.12M | int Al = cinfo->Al; |
371 | 3.12M | register int s, k, r; |
372 | 3.12M | unsigned int EOBRUN; |
373 | 3.12M | JBLOCKROW block; |
374 | 3.12M | BITREAD_STATE_VARS; |
375 | 3.12M | d_derived_tbl *tbl; |
376 | | |
377 | | /* Process restart marker if needed; may have to suspend */ |
378 | 3.12M | if (cinfo->restart_interval) { |
379 | 1.69M | if (entropy->restarts_to_go == 0) |
380 | 40.8k | if (!process_restart(cinfo)) |
381 | 0 | return FALSE; |
382 | 1.69M | } |
383 | | |
384 | | /* If we've run out of data, just leave the MCU set to zeroes. |
385 | | * This way, we return uniform gray for the remainder of the segment. |
386 | | */ |
387 | 3.12M | if (!entropy->pub.insufficient_data) { |
388 | | |
389 | | /* Load up working state. |
390 | | * We can avoid loading/saving bitread state if in an EOB run. |
391 | | */ |
392 | 1.08M | EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */ |
393 | | |
394 | | /* There is always only one block per MCU */ |
395 | | |
396 | 1.08M | if (EOBRUN > 0) /* if it's a band of zeroes... */ |
397 | 847k | EOBRUN--; /* ...process it now (we do nothing) */ |
398 | 237k | else { |
399 | 237k | BITREAD_LOAD_STATE(cinfo, entropy->bitstate); |
400 | 237k | block = MCU_data[0]; |
401 | 237k | tbl = entropy->ac_derived_tbl; |
402 | | |
403 | 1.47M | for (k = cinfo->Ss; k <= Se; k++) { |
404 | 1.39M | HUFF_DECODE(s, br_state, tbl, return FALSE, label2); |
405 | 1.39M | r = s >> 4; |
406 | 1.39M | s &= 15; |
407 | 1.39M | if (s) { |
408 | 1.23M | k += r; |
409 | 1.23M | CHECK_BIT_BUFFER(br_state, s, return FALSE); |
410 | 1.23M | r = GET_BITS(s); |
411 | 1.23M | s = HUFF_EXTEND(r, s); |
412 | | /* Scale and output coefficient in natural (dezigzagged) order */ |
413 | 1.23M | (*block)[jpeg_natural_order[k]] = (JCOEF)LEFT_SHIFT(s, Al); |
414 | 1.23M | } else { |
415 | 157k | if (r == 15) { /* ZRL */ |
416 | 3.46k | k += 15; /* skip 15 zeroes in band */ |
417 | 153k | } else { /* EOBr, run length is 2^r + appended bits */ |
418 | 153k | EOBRUN = 1 << r; |
419 | 153k | if (r) { /* EOBr, r > 0 */ |
420 | 8.97k | CHECK_BIT_BUFFER(br_state, r, return FALSE); |
421 | 8.97k | r = GET_BITS(r); |
422 | 8.97k | EOBRUN += r; |
423 | 8.97k | } |
424 | 153k | EOBRUN--; /* this band is processed at this moment */ |
425 | 153k | break; /* force end-of-band */ |
426 | 153k | } |
427 | 157k | } |
428 | 1.39M | } |
429 | | |
430 | 237k | BITREAD_SAVE_STATE(cinfo, entropy->bitstate); |
431 | 237k | } |
432 | | |
433 | | /* Completed MCU, so update state */ |
434 | 1.08M | entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */ |
435 | 1.08M | } |
436 | | |
437 | | /* Account for restart interval (no-op if not using restarts) */ |
438 | 3.12M | if (cinfo->restart_interval) |
439 | 1.69M | entropy->restarts_to_go--; |
440 | | |
441 | 3.12M | return TRUE; |
442 | 3.12M | } |
443 | | |
444 | | |
445 | | /* |
446 | | * MCU decoding for DC successive approximation refinement scan. |
447 | | * Note: we assume such scans can be multi-component, although the spec |
448 | | * is not very clear on the point. |
449 | | */ |
450 | | |
451 | | METHODDEF(boolean) |
452 | | decode_mcu_DC_refine(j_decompress_ptr cinfo, JBLOCKROW *MCU_data) |
453 | 630k | { |
454 | 630k | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
455 | 630k | int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */ |
456 | 630k | int blkn; |
457 | 630k | JBLOCKROW block; |
458 | 630k | BITREAD_STATE_VARS; |
459 | | |
460 | | /* Process restart marker if needed; may have to suspend */ |
461 | 630k | if (cinfo->restart_interval) { |
462 | 561k | if (entropy->restarts_to_go == 0) |
463 | 135k | if (!process_restart(cinfo)) |
464 | 0 | return FALSE; |
465 | 561k | } |
466 | | |
467 | | /* Not worth the cycles to check insufficient_data here, |
468 | | * since we will not change the data anyway if we read zeroes. |
469 | | */ |
470 | | |
471 | | /* Load up working state */ |
472 | 630k | BITREAD_LOAD_STATE(cinfo, entropy->bitstate); |
473 | | |
474 | | /* Outer loop handles each block in the MCU */ |
475 | | |
476 | 1.62M | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { |
477 | 998k | block = MCU_data[blkn]; |
478 | | |
479 | | /* Encoded data is simply the next bit of the two's-complement DC value */ |
480 | 998k | CHECK_BIT_BUFFER(br_state, 1, return FALSE); |
481 | 998k | if (GET_BITS(1)) |
482 | 34.8k | (*block)[0] |= p1; |
483 | | /* Note: since we use |=, repeating the assignment later is safe */ |
484 | 998k | } |
485 | | |
486 | | /* Completed MCU, so update state */ |
487 | 630k | BITREAD_SAVE_STATE(cinfo, entropy->bitstate); |
488 | | |
489 | | /* Account for restart interval (no-op if not using restarts) */ |
490 | 630k | if (cinfo->restart_interval) |
491 | 561k | entropy->restarts_to_go--; |
492 | | |
493 | 630k | return TRUE; |
494 | 630k | } |
495 | | |
496 | | |
497 | | /* |
498 | | * MCU decoding for AC successive approximation refinement scan. |
499 | | */ |
500 | | |
501 | | METHODDEF(boolean) |
502 | | decode_mcu_AC_refine(j_decompress_ptr cinfo, JBLOCKROW *MCU_data) |
503 | 9.15M | { |
504 | 9.15M | phuff_entropy_ptr entropy = (phuff_entropy_ptr)cinfo->entropy; |
505 | 9.15M | int Se = cinfo->Se; |
506 | 9.15M | int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */ |
507 | 9.15M | int m1 = (NEG_1) << cinfo->Al; /* -1 in the bit position being coded */ |
508 | 9.15M | register int s, k, r; |
509 | 9.15M | unsigned int EOBRUN; |
510 | 9.15M | JBLOCKROW block; |
511 | 9.15M | JCOEFPTR thiscoef; |
512 | 9.15M | BITREAD_STATE_VARS; |
513 | 9.15M | d_derived_tbl *tbl; |
514 | 9.15M | int num_newnz; |
515 | 9.15M | int newnz_pos[DCTSIZE2]; |
516 | | |
517 | | /* Process restart marker if needed; may have to suspend */ |
518 | 9.15M | if (cinfo->restart_interval) { |
519 | 864k | if (entropy->restarts_to_go == 0) |
520 | 126k | if (!process_restart(cinfo)) |
521 | 0 | return FALSE; |
522 | 864k | } |
523 | | |
524 | | /* If we've run out of data, don't modify the MCU. |
525 | | */ |
526 | 9.15M | if (!entropy->pub.insufficient_data) { |
527 | | |
528 | | /* Load up working state */ |
529 | 2.64M | BITREAD_LOAD_STATE(cinfo, entropy->bitstate); |
530 | 2.64M | EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */ |
531 | | |
532 | | /* There is always only one block per MCU */ |
533 | 2.64M | block = MCU_data[0]; |
534 | 2.64M | tbl = entropy->ac_derived_tbl; |
535 | | |
536 | | /* If we are forced to suspend, we must undo the assignments to any newly |
537 | | * nonzero coefficients in the block, because otherwise we'd get confused |
538 | | * next time about which coefficients were already nonzero. |
539 | | * But we need not undo addition of bits to already-nonzero coefficients; |
540 | | * instead, we can test the current bit to see if we already did it. |
541 | | */ |
542 | 2.64M | num_newnz = 0; |
543 | | |
544 | | /* initialize coefficient loop counter to start of band */ |
545 | 2.64M | k = cinfo->Ss; |
546 | | |
547 | 2.64M | if (EOBRUN == 0) { |
548 | 6.01M | for (; k <= Se; k++) { |
549 | 4.92M | HUFF_DECODE(s, br_state, tbl, goto undoit, label3); |
550 | 4.92M | r = s >> 4; |
551 | 4.92M | s &= 15; |
552 | 4.92M | if (s) { |
553 | 4.13M | if (s != 1) /* size of new coef should always be 1 */ |
554 | 2.07M | WARNMS(cinfo, JWRN_HUFF_BAD_CODE); |
555 | 4.13M | CHECK_BIT_BUFFER(br_state, 1, goto undoit); |
556 | 4.13M | if (GET_BITS(1)) |
557 | 2.14M | s = p1; /* newly nonzero coef is positive */ |
558 | 1.99M | else |
559 | 1.99M | s = m1; /* newly nonzero coef is negative */ |
560 | 4.13M | } else { |
561 | 787k | if (r != 15) { |
562 | 776k | EOBRUN = 1 << r; /* EOBr, run length is 2^r + appended bits */ |
563 | 776k | if (r) { |
564 | 241k | CHECK_BIT_BUFFER(br_state, r, goto undoit); |
565 | 241k | r = GET_BITS(r); |
566 | 241k | EOBRUN += r; |
567 | 241k | } |
568 | 776k | break; /* rest of block is handled by EOB logic */ |
569 | 776k | } |
570 | | /* note s = 0 for processing ZRL */ |
571 | 787k | } |
572 | | /* Advance over already-nonzero coefs and r still-zero coefs, |
573 | | * appending correction bits to the nonzeroes. A correction bit is 1 |
574 | | * if the absolute value of the coefficient must be increased. |
575 | | */ |
576 | 32.4M | do { |
577 | 32.4M | thiscoef = *block + jpeg_natural_order[k]; |
578 | 32.4M | if (*thiscoef != 0) { |
579 | 26.9M | CHECK_BIT_BUFFER(br_state, 1, goto undoit); |
580 | 26.9M | if (GET_BITS(1)) { |
581 | 11.7M | if ((*thiscoef & p1) == 0) { /* do nothing if already set it */ |
582 | 218k | if (*thiscoef >= 0) |
583 | 99.1k | *thiscoef += (JCOEF)p1; |
584 | 119k | else |
585 | 119k | *thiscoef += (JCOEF)m1; |
586 | 218k | } |
587 | 11.7M | } |
588 | 26.9M | } else { |
589 | 5.56M | if (--r < 0) |
590 | 3.17M | break; /* reached target zero coefficient */ |
591 | 5.56M | } |
592 | 29.3M | k++; |
593 | 29.3M | } while (k <= Se); |
594 | 4.15M | if (s) { |
595 | 4.13M | int pos = jpeg_natural_order[k]; |
596 | | /* Output newly nonzero coefficient */ |
597 | 4.13M | (*block)[pos] = (JCOEF)s; |
598 | | /* Remember its position in case we have to suspend */ |
599 | 4.13M | newnz_pos[num_newnz++] = pos; |
600 | 4.13M | } |
601 | 4.15M | } |
602 | 1.86M | } |
603 | | |
604 | 2.64M | if (EOBRUN > 0) { |
605 | | /* Scan any remaining coefficient positions after the end-of-band |
606 | | * (the last newly nonzero coefficient, if any). Append a correction |
607 | | * bit to each already-nonzero coefficient. A correction bit is 1 |
608 | | * if the absolute value of the coefficient must be increased. |
609 | | */ |
610 | 38.3M | for (; k <= Se; k++) { |
611 | 36.7M | thiscoef = *block + jpeg_natural_order[k]; |
612 | 36.7M | if (*thiscoef != 0) { |
613 | 10.6M | CHECK_BIT_BUFFER(br_state, 1, goto undoit); |
614 | 10.6M | if (GET_BITS(1)) { |
615 | 5.85M | if ((*thiscoef & p1) == 0) { /* do nothing if already changed it */ |
616 | 156k | if (*thiscoef >= 0) |
617 | 68.5k | *thiscoef += (JCOEF)p1; |
618 | 87.9k | else |
619 | 87.9k | *thiscoef += (JCOEF)m1; |
620 | 156k | } |
621 | 5.85M | } |
622 | 10.6M | } |
623 | 36.7M | } |
624 | | /* Count one block completed in EOB run */ |
625 | 1.56M | EOBRUN--; |
626 | 1.56M | } |
627 | | |
628 | | /* Completed MCU, so update state */ |
629 | 2.64M | BITREAD_SAVE_STATE(cinfo, entropy->bitstate); |
630 | 2.64M | entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */ |
631 | 2.64M | } |
632 | | |
633 | | /* Account for restart interval (no-op if not using restarts) */ |
634 | 9.15M | if (cinfo->restart_interval) |
635 | 864k | entropy->restarts_to_go--; |
636 | | |
637 | 9.15M | return TRUE; |
638 | | |
639 | 0 | undoit: |
640 | | /* Re-zero any output coefficients that we made newly nonzero */ |
641 | 0 | while (num_newnz > 0) |
642 | 0 | (*block)[newnz_pos[--num_newnz]] = 0; |
643 | |
|
644 | 0 | return FALSE; |
645 | 9.15M | } |
646 | | |
647 | | |
648 | | /* |
649 | | * Module initialization routine for progressive Huffman entropy decoding. |
650 | | */ |
651 | | |
652 | | GLOBAL(void) |
653 | | jinit_phuff_decoder(j_decompress_ptr cinfo) |
654 | 8.61k | { |
655 | 8.61k | phuff_entropy_ptr entropy; |
656 | 8.61k | int *coef_bit_ptr; |
657 | 8.61k | int ci, i; |
658 | | |
659 | 8.61k | entropy = (phuff_entropy_ptr) |
660 | 8.61k | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
661 | 8.61k | sizeof(phuff_entropy_decoder)); |
662 | 8.61k | cinfo->entropy = (struct jpeg_entropy_decoder *)entropy; |
663 | 8.61k | entropy->pub.start_pass = start_pass_phuff_decoder; |
664 | | |
665 | | /* Mark derived tables unallocated */ |
666 | 43.0k | for (i = 0; i < NUM_HUFF_TBLS; i++) { |
667 | 34.4k | entropy->derived_tbls[i] = NULL; |
668 | 34.4k | } |
669 | | |
670 | | /* Create progression status table */ |
671 | 8.61k | cinfo->coef_bits = (int (*)[DCTSIZE2]) |
672 | 8.61k | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
673 | 8.61k | cinfo->num_components * 2 * DCTSIZE2 * |
674 | 8.61k | sizeof(int)); |
675 | 8.61k | coef_bit_ptr = &cinfo->coef_bits[0][0]; |
676 | 33.7k | for (ci = 0; ci < cinfo->num_components; ci++) |
677 | 1.63M | for (i = 0; i < DCTSIZE2; i++) |
678 | 1.60M | *coef_bit_ptr++ = -1; |
679 | 8.61k | } |
680 | | |
681 | | #endif /* D_PROGRESSIVE_SUPPORTED */ |