1 /*
2 * Copyright (c) Meta Platforms, Inc. and affiliates.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11 #include "zstd_compress_internal.h"
12 #include "zstd_double_fast.h"
13
14 #ifndef ZSTD_EXCLUDE_DFAST_BLOCK_COMPRESSOR
15
16 static
17 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
ZSTD_fillDoubleHashTableForCDict(ZSTD_MatchState_t * ms,void const * end,ZSTD_dictTableLoadMethod_e dtlm)18 void ZSTD_fillDoubleHashTableForCDict(ZSTD_MatchState_t* ms,
19 void const* end, ZSTD_dictTableLoadMethod_e dtlm)
20 {
21 const ZSTD_compressionParameters* const cParams = &ms->cParams;
22 U32* const hashLarge = ms->hashTable;
23 U32 const hBitsL = cParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
24 U32 const mls = cParams->minMatch;
25 U32* const hashSmall = ms->chainTable;
26 U32 const hBitsS = cParams->chainLog + ZSTD_SHORT_CACHE_TAG_BITS;
27 const BYTE* const base = ms->window.base;
28 const BYTE* ip = base + ms->nextToUpdate;
29 const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
30 const U32 fastHashFillStep = 3;
31
32 /* Always insert every fastHashFillStep position into the hash tables.
33 * Insert the other positions into the large hash table if their entry
34 * is empty.
35 */
36 for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) {
37 U32 const curr = (U32)(ip - base);
38 U32 i;
39 for (i = 0; i < fastHashFillStep; ++i) {
40 size_t const smHashAndTag = ZSTD_hashPtr(ip + i, hBitsS, mls);
41 size_t const lgHashAndTag = ZSTD_hashPtr(ip + i, hBitsL, 8);
42 if (i == 0) {
43 ZSTD_writeTaggedIndex(hashSmall, smHashAndTag, curr + i);
44 }
45 if (i == 0 || hashLarge[lgHashAndTag >> ZSTD_SHORT_CACHE_TAG_BITS] == 0) {
46 ZSTD_writeTaggedIndex(hashLarge, lgHashAndTag, curr + i);
47 }
48 /* Only load extra positions for ZSTD_dtlm_full */
49 if (dtlm == ZSTD_dtlm_fast)
50 break;
51 } }
52 }
53
54 static
55 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
ZSTD_fillDoubleHashTableForCCtx(ZSTD_MatchState_t * ms,void const * end,ZSTD_dictTableLoadMethod_e dtlm)56 void ZSTD_fillDoubleHashTableForCCtx(ZSTD_MatchState_t* ms,
57 void const* end, ZSTD_dictTableLoadMethod_e dtlm)
58 {
59 const ZSTD_compressionParameters* const cParams = &ms->cParams;
60 U32* const hashLarge = ms->hashTable;
61 U32 const hBitsL = cParams->hashLog;
62 U32 const mls = cParams->minMatch;
63 U32* const hashSmall = ms->chainTable;
64 U32 const hBitsS = cParams->chainLog;
65 const BYTE* const base = ms->window.base;
66 const BYTE* ip = base + ms->nextToUpdate;
67 const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
68 const U32 fastHashFillStep = 3;
69
70 /* Always insert every fastHashFillStep position into the hash tables.
71 * Insert the other positions into the large hash table if their entry
72 * is empty.
73 */
74 for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) {
75 U32 const curr = (U32)(ip - base);
76 U32 i;
77 for (i = 0; i < fastHashFillStep; ++i) {
78 size_t const smHash = ZSTD_hashPtr(ip + i, hBitsS, mls);
79 size_t const lgHash = ZSTD_hashPtr(ip + i, hBitsL, 8);
80 if (i == 0)
81 hashSmall[smHash] = curr + i;
82 if (i == 0 || hashLarge[lgHash] == 0)
83 hashLarge[lgHash] = curr + i;
84 /* Only load extra positions for ZSTD_dtlm_full */
85 if (dtlm == ZSTD_dtlm_fast)
86 break;
87 } }
88 }
89
ZSTD_fillDoubleHashTable(ZSTD_MatchState_t * ms,const void * const end,ZSTD_dictTableLoadMethod_e dtlm,ZSTD_tableFillPurpose_e tfp)90 void ZSTD_fillDoubleHashTable(ZSTD_MatchState_t* ms,
91 const void* const end,
92 ZSTD_dictTableLoadMethod_e dtlm,
93 ZSTD_tableFillPurpose_e tfp)
94 {
95 if (tfp == ZSTD_tfp_forCDict) {
96 ZSTD_fillDoubleHashTableForCDict(ms, end, dtlm);
97 } else {
98 ZSTD_fillDoubleHashTableForCCtx(ms, end, dtlm);
99 }
100 }
101
102
103 FORCE_INLINE_TEMPLATE
104 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
ZSTD_compressBlock_doubleFast_noDict_generic(ZSTD_MatchState_t * ms,SeqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize,U32 const mls)105 size_t ZSTD_compressBlock_doubleFast_noDict_generic(
106 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
107 void const* src, size_t srcSize, U32 const mls /* template */)
108 {
109 ZSTD_compressionParameters const* cParams = &ms->cParams;
110 U32* const hashLong = ms->hashTable;
111 const U32 hBitsL = cParams->hashLog;
112 U32* const hashSmall = ms->chainTable;
113 const U32 hBitsS = cParams->chainLog;
114 const BYTE* const base = ms->window.base;
115 const BYTE* const istart = (const BYTE*)src;
116 const BYTE* anchor = istart;
117 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
118 /* presumes that, if there is a dictionary, it must be using Attach mode */
119 const U32 prefixLowestIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
120 const BYTE* const prefixLowest = base + prefixLowestIndex;
121 const BYTE* const iend = istart + srcSize;
122 const BYTE* const ilimit = iend - HASH_READ_SIZE;
123 U32 offset_1=rep[0], offset_2=rep[1];
124 U32 offsetSaved1 = 0, offsetSaved2 = 0;
125
126 size_t mLength;
127 U32 offset;
128 U32 curr;
129
130 /* how many positions to search before increasing step size */
131 const size_t kStepIncr = 1 << kSearchStrength;
132 /* the position at which to increment the step size if no match is found */
133 const BYTE* nextStep;
134 size_t step; /* the current step size */
135
136 size_t hl0; /* the long hash at ip */
137 size_t hl1; /* the long hash at ip1 */
138
139 U32 idxl0; /* the long match index for ip */
140 U32 idxl1; /* the long match index for ip1 */
141
142 const BYTE* matchl0; /* the long match for ip */
143 const BYTE* matchs0; /* the short match for ip */
144 const BYTE* matchl1; /* the long match for ip1 */
145 const BYTE* matchs0_safe; /* matchs0 or safe address */
146
147 const BYTE* ip = istart; /* the current position */
148 const BYTE* ip1; /* the next position */
149 /* Array of ~random data, should have low probability of matching data
150 * we load from here instead of from tables, if matchl0/matchl1 are
151 * invalid indices. Used to avoid unpredictable branches. */
152 const BYTE dummy[] = {0x12,0x34,0x56,0x78,0x9a,0xbc,0xde,0xf0,0xe2,0xb4};
153
154 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_noDict_generic");
155
156 /* init */
157 ip += ((ip - prefixLowest) == 0);
158 {
159 U32 const current = (U32)(ip - base);
160 U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, cParams->windowLog);
161 U32 const maxRep = current - windowLow;
162 if (offset_2 > maxRep) offsetSaved2 = offset_2, offset_2 = 0;
163 if (offset_1 > maxRep) offsetSaved1 = offset_1, offset_1 = 0;
164 }
165
166 /* Outer Loop: one iteration per match found and stored */
167 while (1) {
168 step = 1;
169 nextStep = ip + kStepIncr;
170 ip1 = ip + step;
171
172 if (ip1 > ilimit) {
173 goto _cleanup;
174 }
175
176 hl0 = ZSTD_hashPtr(ip, hBitsL, 8);
177 idxl0 = hashLong[hl0];
178 matchl0 = base + idxl0;
179
180 /* Inner Loop: one iteration per search / position */
181 do {
182 const size_t hs0 = ZSTD_hashPtr(ip, hBitsS, mls);
183 const U32 idxs0 = hashSmall[hs0];
184 curr = (U32)(ip-base);
185 matchs0 = base + idxs0;
186
187 hashLong[hl0] = hashSmall[hs0] = curr; /* update hash tables */
188
189 /* check noDict repcode */
190 if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
191 mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
192 ip++;
193 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, REPCODE1_TO_OFFBASE, mLength);
194 goto _match_stored;
195 }
196
197 hl1 = ZSTD_hashPtr(ip1, hBitsL, 8);
198
199 /* idxl0 > prefixLowestIndex is a (somewhat) unpredictable branch.
200 * However expression below complies into conditional move. Since
201 * match is unlikely and we only *branch* on idxl0 > prefixLowestIndex
202 * if there is a match, all branches become predictable. */
203 { const BYTE* const matchl0_safe = ZSTD_selectAddr(idxl0, prefixLowestIndex, matchl0, &dummy[0]);
204
205 /* check prefix long match */
206 if (MEM_read64(matchl0_safe) == MEM_read64(ip) && matchl0_safe == matchl0) {
207 mLength = ZSTD_count(ip+8, matchl0+8, iend) + 8;
208 offset = (U32)(ip-matchl0);
209 while (((ip>anchor) & (matchl0>prefixLowest)) && (ip[-1] == matchl0[-1])) { ip--; matchl0--; mLength++; } /* catch up */
210 goto _match_found;
211 } }
212
213 idxl1 = hashLong[hl1];
214 matchl1 = base + idxl1;
215
216 /* Same optimization as matchl0 above */
217 matchs0_safe = ZSTD_selectAddr(idxs0, prefixLowestIndex, matchs0, &dummy[0]);
218
219 /* check prefix short match */
220 if(MEM_read32(matchs0_safe) == MEM_read32(ip) && matchs0_safe == matchs0) {
221 goto _search_next_long;
222 }
223
224 if (ip1 >= nextStep) {
225 PREFETCH_L1(ip1 + 64);
226 PREFETCH_L1(ip1 + 128);
227 step++;
228 nextStep += kStepIncr;
229 }
230 ip = ip1;
231 ip1 += step;
232
233 hl0 = hl1;
234 idxl0 = idxl1;
235 matchl0 = matchl1;
236 #if defined(__aarch64__)
237 PREFETCH_L1(ip+256);
238 #endif
239 } while (ip1 <= ilimit);
240
241 _cleanup:
242 /* If offset_1 started invalid (offsetSaved1 != 0) and became valid (offset_1 != 0),
243 * rotate saved offsets. See comment in ZSTD_compressBlock_fast_noDict for more context. */
244 offsetSaved2 = ((offsetSaved1 != 0) && (offset_1 != 0)) ? offsetSaved1 : offsetSaved2;
245
246 /* save reps for next block */
247 rep[0] = offset_1 ? offset_1 : offsetSaved1;
248 rep[1] = offset_2 ? offset_2 : offsetSaved2;
249
250 /* Return the last literals size */
251 return (size_t)(iend - anchor);
252
253 _search_next_long:
254
255 /* short match found: let's check for a longer one */
256 mLength = ZSTD_count(ip+4, matchs0+4, iend) + 4;
257 offset = (U32)(ip - matchs0);
258
259 /* check long match at +1 position */
260 if ((idxl1 > prefixLowestIndex) && (MEM_read64(matchl1) == MEM_read64(ip1))) {
261 size_t const l1len = ZSTD_count(ip1+8, matchl1+8, iend) + 8;
262 if (l1len > mLength) {
263 /* use the long match instead */
264 ip = ip1;
265 mLength = l1len;
266 offset = (U32)(ip-matchl1);
267 matchs0 = matchl1;
268 }
269 }
270
271 while (((ip>anchor) & (matchs0>prefixLowest)) && (ip[-1] == matchs0[-1])) { ip--; matchs0--; mLength++; } /* complete backward */
272
273 /* fall-through */
274
275 _match_found: /* requires ip, offset, mLength */
276 offset_2 = offset_1;
277 offset_1 = offset;
278
279 if (step < 4) {
280 /* It is unsafe to write this value back to the hashtable when ip1 is
281 * greater than or equal to the new ip we will have after we're done
282 * processing this match. Rather than perform that test directly
283 * (ip1 >= ip + mLength), which costs speed in practice, we do a simpler
284 * more predictable test. The minmatch even if we take a short match is
285 * 4 bytes, so as long as step, the distance between ip and ip1
286 * (initially) is less than 4, we know ip1 < new ip. */
287 hashLong[hl1] = (U32)(ip1 - base);
288 }
289
290 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
291
292 _match_stored:
293 /* match found */
294 ip += mLength;
295 anchor = ip;
296
297 if (ip <= ilimit) {
298 /* Complementary insertion */
299 /* done after iLimit test, as candidates could be > iend-8 */
300 { U32 const indexToInsert = curr+2;
301 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
302 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
303 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
304 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
305 }
306
307 /* check immediate repcode */
308 while ( (ip <= ilimit)
309 && ( (offset_2>0)
310 & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
311 /* store sequence */
312 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
313 U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */
314 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
315 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
316 ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, rLength);
317 ip += rLength;
318 anchor = ip;
319 continue; /* faster when present ... (?) */
320 }
321 }
322 }
323 }
324
325
326 FORCE_INLINE_TEMPLATE
327 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
ZSTD_compressBlock_doubleFast_dictMatchState_generic(ZSTD_MatchState_t * ms,SeqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize,U32 const mls)328 size_t ZSTD_compressBlock_doubleFast_dictMatchState_generic(
329 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
330 void const* src, size_t srcSize,
331 U32 const mls /* template */)
332 {
333 ZSTD_compressionParameters const* cParams = &ms->cParams;
334 U32* const hashLong = ms->hashTable;
335 const U32 hBitsL = cParams->hashLog;
336 U32* const hashSmall = ms->chainTable;
337 const U32 hBitsS = cParams->chainLog;
338 const BYTE* const base = ms->window.base;
339 const BYTE* const istart = (const BYTE*)src;
340 const BYTE* ip = istart;
341 const BYTE* anchor = istart;
342 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
343 /* presumes that, if there is a dictionary, it must be using Attach mode */
344 const U32 prefixLowestIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
345 const BYTE* const prefixLowest = base + prefixLowestIndex;
346 const BYTE* const iend = istart + srcSize;
347 const BYTE* const ilimit = iend - HASH_READ_SIZE;
348 U32 offset_1=rep[0], offset_2=rep[1];
349
350 const ZSTD_MatchState_t* const dms = ms->dictMatchState;
351 const ZSTD_compressionParameters* const dictCParams = &dms->cParams;
352 const U32* const dictHashLong = dms->hashTable;
353 const U32* const dictHashSmall = dms->chainTable;
354 const U32 dictStartIndex = dms->window.dictLimit;
355 const BYTE* const dictBase = dms->window.base;
356 const BYTE* const dictStart = dictBase + dictStartIndex;
357 const BYTE* const dictEnd = dms->window.nextSrc;
358 const U32 dictIndexDelta = prefixLowestIndex - (U32)(dictEnd - dictBase);
359 const U32 dictHBitsL = dictCParams->hashLog + ZSTD_SHORT_CACHE_TAG_BITS;
360 const U32 dictHBitsS = dictCParams->chainLog + ZSTD_SHORT_CACHE_TAG_BITS;
361 const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictStart));
362
363 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_dictMatchState_generic");
364
365 /* if a dictionary is attached, it must be within window range */
366 assert(ms->window.dictLimit + (1U << cParams->windowLog) >= endIndex);
367
368 if (ms->prefetchCDictTables) {
369 size_t const hashTableBytes = (((size_t)1) << dictCParams->hashLog) * sizeof(U32);
370 size_t const chainTableBytes = (((size_t)1) << dictCParams->chainLog) * sizeof(U32);
371 PREFETCH_AREA(dictHashLong, hashTableBytes);
372 PREFETCH_AREA(dictHashSmall, chainTableBytes);
373 }
374
375 /* init */
376 ip += (dictAndPrefixLength == 0);
377
378 /* dictMatchState repCode checks don't currently handle repCode == 0
379 * disabling. */
380 assert(offset_1 <= dictAndPrefixLength);
381 assert(offset_2 <= dictAndPrefixLength);
382
383 /* Main Search Loop */
384 while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
385 size_t mLength;
386 U32 offset;
387 size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
388 size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
389 size_t const dictHashAndTagL = ZSTD_hashPtr(ip, dictHBitsL, 8);
390 size_t const dictHashAndTagS = ZSTD_hashPtr(ip, dictHBitsS, mls);
391 U32 const dictMatchIndexAndTagL = dictHashLong[dictHashAndTagL >> ZSTD_SHORT_CACHE_TAG_BITS];
392 U32 const dictMatchIndexAndTagS = dictHashSmall[dictHashAndTagS >> ZSTD_SHORT_CACHE_TAG_BITS];
393 int const dictTagsMatchL = ZSTD_comparePackedTags(dictMatchIndexAndTagL, dictHashAndTagL);
394 int const dictTagsMatchS = ZSTD_comparePackedTags(dictMatchIndexAndTagS, dictHashAndTagS);
395 U32 const curr = (U32)(ip-base);
396 U32 const matchIndexL = hashLong[h2];
397 U32 matchIndexS = hashSmall[h];
398 const BYTE* matchLong = base + matchIndexL;
399 const BYTE* match = base + matchIndexS;
400 const U32 repIndex = curr + 1 - offset_1;
401 const BYTE* repMatch = (repIndex < prefixLowestIndex) ?
402 dictBase + (repIndex - dictIndexDelta) :
403 base + repIndex;
404 hashLong[h2] = hashSmall[h] = curr; /* update hash tables */
405
406 /* check repcode */
407 if ((ZSTD_index_overlap_check(prefixLowestIndex, repIndex))
408 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
409 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
410 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
411 ip++;
412 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, REPCODE1_TO_OFFBASE, mLength);
413 goto _match_stored;
414 }
415
416 if ((matchIndexL >= prefixLowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
417 /* check prefix long match */
418 mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
419 offset = (U32)(ip-matchLong);
420 while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
421 goto _match_found;
422 } else if (dictTagsMatchL) {
423 /* check dictMatchState long match */
424 U32 const dictMatchIndexL = dictMatchIndexAndTagL >> ZSTD_SHORT_CACHE_TAG_BITS;
425 const BYTE* dictMatchL = dictBase + dictMatchIndexL;
426 assert(dictMatchL < dictEnd);
427
428 if (dictMatchL > dictStart && MEM_read64(dictMatchL) == MEM_read64(ip)) {
429 mLength = ZSTD_count_2segments(ip+8, dictMatchL+8, iend, dictEnd, prefixLowest) + 8;
430 offset = (U32)(curr - dictMatchIndexL - dictIndexDelta);
431 while (((ip>anchor) & (dictMatchL>dictStart)) && (ip[-1] == dictMatchL[-1])) { ip--; dictMatchL--; mLength++; } /* catch up */
432 goto _match_found;
433 } }
434
435 if (matchIndexS > prefixLowestIndex) {
436 /* short match candidate */
437 if (MEM_read32(match) == MEM_read32(ip)) {
438 goto _search_next_long;
439 }
440 } else if (dictTagsMatchS) {
441 /* check dictMatchState short match */
442 U32 const dictMatchIndexS = dictMatchIndexAndTagS >> ZSTD_SHORT_CACHE_TAG_BITS;
443 match = dictBase + dictMatchIndexS;
444 matchIndexS = dictMatchIndexS + dictIndexDelta;
445
446 if (match > dictStart && MEM_read32(match) == MEM_read32(ip)) {
447 goto _search_next_long;
448 } }
449
450 ip += ((ip-anchor) >> kSearchStrength) + 1;
451 #if defined(__aarch64__)
452 PREFETCH_L1(ip+256);
453 #endif
454 continue;
455
456 _search_next_long:
457 { size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
458 size_t const dictHashAndTagL3 = ZSTD_hashPtr(ip+1, dictHBitsL, 8);
459 U32 const matchIndexL3 = hashLong[hl3];
460 U32 const dictMatchIndexAndTagL3 = dictHashLong[dictHashAndTagL3 >> ZSTD_SHORT_CACHE_TAG_BITS];
461 int const dictTagsMatchL3 = ZSTD_comparePackedTags(dictMatchIndexAndTagL3, dictHashAndTagL3);
462 const BYTE* matchL3 = base + matchIndexL3;
463 hashLong[hl3] = curr + 1;
464
465 /* check prefix long +1 match */
466 if ((matchIndexL3 >= prefixLowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1))) {
467 mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
468 ip++;
469 offset = (U32)(ip-matchL3);
470 while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
471 goto _match_found;
472 } else if (dictTagsMatchL3) {
473 /* check dict long +1 match */
474 U32 const dictMatchIndexL3 = dictMatchIndexAndTagL3 >> ZSTD_SHORT_CACHE_TAG_BITS;
475 const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
476 assert(dictMatchL3 < dictEnd);
477 if (dictMatchL3 > dictStart && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) {
478 mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, prefixLowest) + 8;
479 ip++;
480 offset = (U32)(curr + 1 - dictMatchIndexL3 - dictIndexDelta);
481 while (((ip>anchor) & (dictMatchL3>dictStart)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */
482 goto _match_found;
483 } } }
484
485 /* if no long +1 match, explore the short match we found */
486 if (matchIndexS < prefixLowestIndex) {
487 mLength = ZSTD_count_2segments(ip+4, match+4, iend, dictEnd, prefixLowest) + 4;
488 offset = (U32)(curr - matchIndexS);
489 while (((ip>anchor) & (match>dictStart)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
490 } else {
491 mLength = ZSTD_count(ip+4, match+4, iend) + 4;
492 offset = (U32)(ip - match);
493 while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
494 }
495
496 _match_found:
497 offset_2 = offset_1;
498 offset_1 = offset;
499
500 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
501
502 _match_stored:
503 /* match found */
504 ip += mLength;
505 anchor = ip;
506
507 if (ip <= ilimit) {
508 /* Complementary insertion */
509 /* done after iLimit test, as candidates could be > iend-8 */
510 { U32 const indexToInsert = curr+2;
511 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
512 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
513 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
514 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
515 }
516
517 /* check immediate repcode */
518 while (ip <= ilimit) {
519 U32 const current2 = (U32)(ip-base);
520 U32 const repIndex2 = current2 - offset_2;
521 const BYTE* repMatch2 = repIndex2 < prefixLowestIndex ?
522 dictBase + repIndex2 - dictIndexDelta :
523 base + repIndex2;
524 if ( (ZSTD_index_overlap_check(prefixLowestIndex, repIndex2))
525 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
526 const BYTE* const repEnd2 = repIndex2 < prefixLowestIndex ? dictEnd : iend;
527 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixLowest) + 4;
528 U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
529 ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, repLength2);
530 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
531 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
532 ip += repLength2;
533 anchor = ip;
534 continue;
535 }
536 break;
537 }
538 }
539 } /* while (ip < ilimit) */
540
541 /* save reps for next block */
542 rep[0] = offset_1;
543 rep[1] = offset_2;
544
545 /* Return the last literals size */
546 return (size_t)(iend - anchor);
547 }
548
549 #define ZSTD_GEN_DFAST_FN(dictMode, mls) \
550 static size_t ZSTD_compressBlock_doubleFast_##dictMode##_##mls( \
551 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], \
552 void const* src, size_t srcSize) \
553 { \
554 return ZSTD_compressBlock_doubleFast_##dictMode##_generic(ms, seqStore, rep, src, srcSize, mls); \
555 }
556
557 ZSTD_GEN_DFAST_FN(noDict, 4)
558 ZSTD_GEN_DFAST_FN(noDict, 5)
559 ZSTD_GEN_DFAST_FN(noDict, 6)
560 ZSTD_GEN_DFAST_FN(noDict, 7)
561
562 ZSTD_GEN_DFAST_FN(dictMatchState, 4)
563 ZSTD_GEN_DFAST_FN(dictMatchState, 5)
564 ZSTD_GEN_DFAST_FN(dictMatchState, 6)
565 ZSTD_GEN_DFAST_FN(dictMatchState, 7)
566
567
ZSTD_compressBlock_doubleFast(ZSTD_MatchState_t * ms,SeqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)568 size_t ZSTD_compressBlock_doubleFast(
569 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
570 void const* src, size_t srcSize)
571 {
572 const U32 mls = ms->cParams.minMatch;
573 switch(mls)
574 {
575 default: /* includes case 3 */
576 case 4 :
577 return ZSTD_compressBlock_doubleFast_noDict_4(ms, seqStore, rep, src, srcSize);
578 case 5 :
579 return ZSTD_compressBlock_doubleFast_noDict_5(ms, seqStore, rep, src, srcSize);
580 case 6 :
581 return ZSTD_compressBlock_doubleFast_noDict_6(ms, seqStore, rep, src, srcSize);
582 case 7 :
583 return ZSTD_compressBlock_doubleFast_noDict_7(ms, seqStore, rep, src, srcSize);
584 }
585 }
586
587
ZSTD_compressBlock_doubleFast_dictMatchState(ZSTD_MatchState_t * ms,SeqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)588 size_t ZSTD_compressBlock_doubleFast_dictMatchState(
589 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
590 void const* src, size_t srcSize)
591 {
592 const U32 mls = ms->cParams.minMatch;
593 switch(mls)
594 {
595 default: /* includes case 3 */
596 case 4 :
597 return ZSTD_compressBlock_doubleFast_dictMatchState_4(ms, seqStore, rep, src, srcSize);
598 case 5 :
599 return ZSTD_compressBlock_doubleFast_dictMatchState_5(ms, seqStore, rep, src, srcSize);
600 case 6 :
601 return ZSTD_compressBlock_doubleFast_dictMatchState_6(ms, seqStore, rep, src, srcSize);
602 case 7 :
603 return ZSTD_compressBlock_doubleFast_dictMatchState_7(ms, seqStore, rep, src, srcSize);
604 }
605 }
606
607
608 static
609 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_MatchState_t * ms,SeqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize,U32 const mls)610 size_t ZSTD_compressBlock_doubleFast_extDict_generic(
611 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
612 void const* src, size_t srcSize,
613 U32 const mls /* template */)
614 {
615 ZSTD_compressionParameters const* cParams = &ms->cParams;
616 U32* const hashLong = ms->hashTable;
617 U32 const hBitsL = cParams->hashLog;
618 U32* const hashSmall = ms->chainTable;
619 U32 const hBitsS = cParams->chainLog;
620 const BYTE* const istart = (const BYTE*)src;
621 const BYTE* ip = istart;
622 const BYTE* anchor = istart;
623 const BYTE* const iend = istart + srcSize;
624 const BYTE* const ilimit = iend - 8;
625 const BYTE* const base = ms->window.base;
626 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
627 const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
628 const U32 dictStartIndex = lowLimit;
629 const U32 dictLimit = ms->window.dictLimit;
630 const U32 prefixStartIndex = (dictLimit > lowLimit) ? dictLimit : lowLimit;
631 const BYTE* const prefixStart = base + prefixStartIndex;
632 const BYTE* const dictBase = ms->window.dictBase;
633 const BYTE* const dictStart = dictBase + dictStartIndex;
634 const BYTE* const dictEnd = dictBase + prefixStartIndex;
635 U32 offset_1=rep[0], offset_2=rep[1];
636
637 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_extDict_generic (srcSize=%zu)", srcSize);
638
639 /* if extDict is invalidated due to maxDistance, switch to "regular" variant */
640 if (prefixStartIndex == dictStartIndex)
641 return ZSTD_compressBlock_doubleFast(ms, seqStore, rep, src, srcSize);
642
643 /* Search Loop */
644 while (ip < ilimit) { /* < instead of <=, because (ip+1) */
645 const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
646 const U32 matchIndex = hashSmall[hSmall];
647 const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
648 const BYTE* match = matchBase + matchIndex;
649
650 const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
651 const U32 matchLongIndex = hashLong[hLong];
652 const BYTE* const matchLongBase = matchLongIndex < prefixStartIndex ? dictBase : base;
653 const BYTE* matchLong = matchLongBase + matchLongIndex;
654
655 const U32 curr = (U32)(ip-base);
656 const U32 repIndex = curr + 1 - offset_1; /* offset_1 expected <= curr +1 */
657 const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
658 const BYTE* const repMatch = repBase + repIndex;
659 size_t mLength;
660 hashSmall[hSmall] = hashLong[hLong] = curr; /* update hash table */
661
662 if (((ZSTD_index_overlap_check(prefixStartIndex, repIndex))
663 & (offset_1 <= curr+1 - dictStartIndex)) /* note: we are searching at curr+1 */
664 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
665 const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
666 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
667 ip++;
668 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, REPCODE1_TO_OFFBASE, mLength);
669 } else {
670 if ((matchLongIndex > dictStartIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
671 const BYTE* const matchEnd = matchLongIndex < prefixStartIndex ? dictEnd : iend;
672 const BYTE* const lowMatchPtr = matchLongIndex < prefixStartIndex ? dictStart : prefixStart;
673 U32 offset;
674 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, prefixStart) + 8;
675 offset = curr - matchLongIndex;
676 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
677 offset_2 = offset_1;
678 offset_1 = offset;
679 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
680
681 } else if ((matchIndex > dictStartIndex) && (MEM_read32(match) == MEM_read32(ip))) {
682 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
683 U32 const matchIndex3 = hashLong[h3];
684 const BYTE* const match3Base = matchIndex3 < prefixStartIndex ? dictBase : base;
685 const BYTE* match3 = match3Base + matchIndex3;
686 U32 offset;
687 hashLong[h3] = curr + 1;
688 if ( (matchIndex3 > dictStartIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
689 const BYTE* const matchEnd = matchIndex3 < prefixStartIndex ? dictEnd : iend;
690 const BYTE* const lowMatchPtr = matchIndex3 < prefixStartIndex ? dictStart : prefixStart;
691 mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, prefixStart) + 8;
692 ip++;
693 offset = curr+1 - matchIndex3;
694 while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
695 } else {
696 const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
697 const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
698 mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
699 offset = curr - matchIndex;
700 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
701 }
702 offset_2 = offset_1;
703 offset_1 = offset;
704 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, OFFSET_TO_OFFBASE(offset), mLength);
705
706 } else {
707 ip += ((ip-anchor) >> kSearchStrength) + 1;
708 continue;
709 } }
710
711 /* move to next sequence start */
712 ip += mLength;
713 anchor = ip;
714
715 if (ip <= ilimit) {
716 /* Complementary insertion */
717 /* done after iLimit test, as candidates could be > iend-8 */
718 { U32 const indexToInsert = curr+2;
719 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
720 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
721 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
722 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
723 }
724
725 /* check immediate repcode */
726 while (ip <= ilimit) {
727 U32 const current2 = (U32)(ip-base);
728 U32 const repIndex2 = current2 - offset_2;
729 const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
730 if ( ((ZSTD_index_overlap_check(prefixStartIndex, repIndex2))
731 & (offset_2 <= current2 - dictStartIndex))
732 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
733 const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
734 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
735 U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
736 ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, repLength2);
737 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
738 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
739 ip += repLength2;
740 anchor = ip;
741 continue;
742 }
743 break;
744 } } }
745
746 /* save reps for next block */
747 rep[0] = offset_1;
748 rep[1] = offset_2;
749
750 /* Return the last literals size */
751 return (size_t)(iend - anchor);
752 }
753
754 ZSTD_GEN_DFAST_FN(extDict, 4)
755 ZSTD_GEN_DFAST_FN(extDict, 5)
756 ZSTD_GEN_DFAST_FN(extDict, 6)
757 ZSTD_GEN_DFAST_FN(extDict, 7)
758
ZSTD_compressBlock_doubleFast_extDict(ZSTD_MatchState_t * ms,SeqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)759 size_t ZSTD_compressBlock_doubleFast_extDict(
760 ZSTD_MatchState_t* ms, SeqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
761 void const* src, size_t srcSize)
762 {
763 U32 const mls = ms->cParams.minMatch;
764 switch(mls)
765 {
766 default: /* includes case 3 */
767 case 4 :
768 return ZSTD_compressBlock_doubleFast_extDict_4(ms, seqStore, rep, src, srcSize);
769 case 5 :
770 return ZSTD_compressBlock_doubleFast_extDict_5(ms, seqStore, rep, src, srcSize);
771 case 6 :
772 return ZSTD_compressBlock_doubleFast_extDict_6(ms, seqStore, rep, src, srcSize);
773 case 7 :
774 return ZSTD_compressBlock_doubleFast_extDict_7(ms, seqStore, rep, src, srcSize);
775 }
776 }
777
778 #endif /* ZSTD_EXCLUDE_DFAST_BLOCK_COMPRESSOR */
779