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1/*
2 * Copyright (c) Yann Collet, Facebook, Inc.
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_lazy.h"
13
14
15/*-*************************************
16* Binary Tree search
17***************************************/
18
19static void
20ZSTD_updateDUBT(ZSTD_matchState_t* ms,
21 const BYTE* ip, const BYTE* iend,
22 U32 mls)
23{
24 const ZSTD_compressionParameters* const cParams = &ms->cParams;
25 U32* const hashTable = ms->hashTable;
26 U32 const hashLog = cParams->hashLog;
27
28 U32* const bt = ms->chainTable;
29 U32 const btLog = cParams->chainLog - 1;
30 U32 const btMask = (1 << btLog) - 1;
31
32 const BYTE* const base = ms->window.base;
33 U32 const target = (U32)(ip - base);
34 U32 idx = ms->nextToUpdate;
35
36 if (idx != target)
37 DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)",
38 idx, target, ms->window.dictLimit);
39 assert(ip + 8 <= iend); /* condition for ZSTD_hashPtr */
40 (void)iend;
41
42 assert(idx >= ms->window.dictLimit); /* condition for valid base+idx */
43 for ( ; idx < target ; idx++) {
44 size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls); /* assumption : ip + 8 <= iend */
45 U32 const matchIndex = hashTable[h];
46
47 U32* const nextCandidatePtr = bt + 2*(idx&btMask);
48 U32* const sortMarkPtr = nextCandidatePtr + 1;
49
50 DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx);
51 hashTable[h] = idx; /* Update Hash Table */
52 *nextCandidatePtr = matchIndex; /* update BT like a chain */
53 *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK;
54 }
55 ms->nextToUpdate = target;
56}
57
58
59/* ZSTD_insertDUBT1() :
60 * sort one already inserted but unsorted position
61 * assumption : curr >= btlow == (curr - btmask)
62 * doesn't fail */
63static void
64ZSTD_insertDUBT1(const ZSTD_matchState_t* ms,
65 U32 curr, const BYTE* inputEnd,
66 U32 nbCompares, U32 btLow,
67 const ZSTD_dictMode_e dictMode)
68{
69 const ZSTD_compressionParameters* const cParams = &ms->cParams;
70 U32* const bt = ms->chainTable;
71 U32 const btLog = cParams->chainLog - 1;
72 U32 const btMask = (1 << btLog) - 1;
73 size_t commonLengthSmaller=0, commonLengthLarger=0;
74 const BYTE* const base = ms->window.base;
75 const BYTE* const dictBase = ms->window.dictBase;
76 const U32 dictLimit = ms->window.dictLimit;
77 const BYTE* const ip = (curr>=dictLimit) ? base + curr : dictBase + curr;
78 const BYTE* const iend = (curr>=dictLimit) ? inputEnd : dictBase + dictLimit;
79 const BYTE* const dictEnd = dictBase + dictLimit;
80 const BYTE* const prefixStart = base + dictLimit;
81 const BYTE* match;
82 U32* smallerPtr = bt + 2*(curr&btMask);
83 U32* largerPtr = smallerPtr + 1;
84 U32 matchIndex = *smallerPtr; /* this candidate is unsorted : next sorted candidate is reached through *smallerPtr, while *largerPtr contains previous unsorted candidate (which is already saved and can be overwritten) */
85 U32 dummy32; /* to be nullified at the end */
86 U32 const windowValid = ms->window.lowLimit;
87 U32 const maxDistance = 1U << cParams->windowLog;
88 U32 const windowLow = (curr - windowValid > maxDistance) ? curr - maxDistance : windowValid;
89
90
91 DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
92 curr, dictLimit, windowLow);
93 assert(curr >= btLow);
94 assert(ip < iend); /* condition for ZSTD_count */
95
96 for (; nbCompares && (matchIndex > windowLow); --nbCompares) {
97 U32* const nextPtr = bt + 2*(matchIndex & btMask);
98 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
99 assert(matchIndex < curr);
100 /* note : all candidates are now supposed sorted,
101 * but it's still possible to have nextPtr[1] == ZSTD_DUBT_UNSORTED_MARK
102 * when a real index has the same value as ZSTD_DUBT_UNSORTED_MARK */
103
104 if ( (dictMode != ZSTD_extDict)
105 || (matchIndex+matchLength >= dictLimit) /* both in current segment*/
106 || (curr < dictLimit) /* both in extDict */) {
107 const BYTE* const mBase = ( (dictMode != ZSTD_extDict)
108 || (matchIndex+matchLength >= dictLimit)) ?
109 base : dictBase;
110 assert( (matchIndex+matchLength >= dictLimit) /* might be wrong if extDict is incorrectly set to 0 */
111 || (curr < dictLimit) );
112 match = mBase + matchIndex;
113 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
114 } else {
115 match = dictBase + matchIndex;
116 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
117 if (matchIndex+matchLength >= dictLimit)
118 match = base + matchIndex; /* preparation for next read of match[matchLength] */
119 }
120
121 DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ",
122 curr, matchIndex, (U32)matchLength);
123
124 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
125 break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
126 }
127
128 if (match[matchLength] < ip[matchLength]) { /* necessarily within buffer */
129 /* match is smaller than current */
130 *smallerPtr = matchIndex; /* update smaller idx */
131 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
132 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop searching */
133 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u",
134 matchIndex, btLow, nextPtr[1]);
135 smallerPtr = nextPtr+1; /* new "candidate" => larger than match, which was smaller than target */
136 matchIndex = nextPtr[1]; /* new matchIndex, larger than previous and closer to current */
137 } else {
138 /* match is larger than current */
139 *largerPtr = matchIndex;
140 commonLengthLarger = matchLength;
141 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop searching */
142 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u",
143 matchIndex, btLow, nextPtr[0]);
144 largerPtr = nextPtr;
145 matchIndex = nextPtr[0];
146 } }
147
148 *smallerPtr = *largerPtr = 0;
149}
150
151
152static size_t
153ZSTD_DUBT_findBetterDictMatch (
154 const ZSTD_matchState_t* ms,
155 const BYTE* const ip, const BYTE* const iend,
156 size_t* offsetPtr,
157 size_t bestLength,
158 U32 nbCompares,
159 U32 const mls,
160 const ZSTD_dictMode_e dictMode)
161{
162 const ZSTD_matchState_t * const dms = ms->dictMatchState;
163 const ZSTD_compressionParameters* const dmsCParams = &dms->cParams;
164 const U32 * const dictHashTable = dms->hashTable;
165 U32 const hashLog = dmsCParams->hashLog;
166 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
167 U32 dictMatchIndex = dictHashTable[h];
168
169 const BYTE* const base = ms->window.base;
170 const BYTE* const prefixStart = base + ms->window.dictLimit;
171 U32 const curr = (U32)(ip-base);
172 const BYTE* const dictBase = dms->window.base;
173 const BYTE* const dictEnd = dms->window.nextSrc;
174 U32 const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base);
175 U32 const dictLowLimit = dms->window.lowLimit;
176 U32 const dictIndexDelta = ms->window.lowLimit - dictHighLimit;
177
178 U32* const dictBt = dms->chainTable;
179 U32 const btLog = dmsCParams->chainLog - 1;
180 U32 const btMask = (1 << btLog) - 1;
181 U32 const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask;
182
183 size_t commonLengthSmaller=0, commonLengthLarger=0;
184
185 (void)dictMode;
186 assert(dictMode == ZSTD_dictMatchState);
187
188 for (; nbCompares && (dictMatchIndex > dictLowLimit); --nbCompares) {
189 U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask);
190 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
191 const BYTE* match = dictBase + dictMatchIndex;
192 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
193 if (dictMatchIndex+matchLength >= dictHighLimit)
194 match = base + dictMatchIndex + dictIndexDelta; /* to prepare for next usage of match[matchLength] */
195
196 if (matchLength > bestLength) {
197 U32 matchIndex = dictMatchIndex + dictIndexDelta;
198 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(curr-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) {
199 DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)",
200 curr, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, STORE_OFFSET(curr - matchIndex), dictMatchIndex, matchIndex);
201 bestLength = matchLength, *offsetPtr = STORE_OFFSET(curr - matchIndex);
202 }
203 if (ip+matchLength == iend) { /* reached end of input : ip[matchLength] is not valid, no way to know if it's larger or smaller than match */
204 break; /* drop, to guarantee consistency (miss a little bit of compression) */
205 }
206 }
207
208 if (match[matchLength] < ip[matchLength]) {
209 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */
210 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
211 dictMatchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
212 } else {
213 /* match is larger than current */
214 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */
215 commonLengthLarger = matchLength;
216 dictMatchIndex = nextPtr[0];
217 }
218 }
219
220 if (bestLength >= MINMATCH) {
221 U32 const mIndex = curr - (U32)STORED_OFFSET(*offsetPtr); (void)mIndex;
222 DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
223 curr, (U32)bestLength, (U32)*offsetPtr, mIndex);
224 }
225 return bestLength;
226
227}
228
229
230static size_t
231ZSTD_DUBT_findBestMatch(ZSTD_matchState_t* ms,
232 const BYTE* const ip, const BYTE* const iend,
233 size_t* offsetPtr,
234 U32 const mls,
235 const ZSTD_dictMode_e dictMode)
236{
237 const ZSTD_compressionParameters* const cParams = &ms->cParams;
238 U32* const hashTable = ms->hashTable;
239 U32 const hashLog = cParams->hashLog;
240 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
241 U32 matchIndex = hashTable[h];
242
243 const BYTE* const base = ms->window.base;
244 U32 const curr = (U32)(ip-base);
245 U32 const windowLow = ZSTD_getLowestMatchIndex(ms, curr, cParams->windowLog);
246
247 U32* const bt = ms->chainTable;
248 U32 const btLog = cParams->chainLog - 1;
249 U32 const btMask = (1 << btLog) - 1;
250 U32 const btLow = (btMask >= curr) ? 0 : curr - btMask;
251 U32 const unsortLimit = MAX(btLow, windowLow);
252
253 U32* nextCandidate = bt + 2*(matchIndex&btMask);
254 U32* unsortedMark = bt + 2*(matchIndex&btMask) + 1;
255 U32 nbCompares = 1U << cParams->searchLog;
256 U32 nbCandidates = nbCompares;
257 U32 previousCandidate = 0;
258
259 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", curr);
260 assert(ip <= iend-8); /* required for h calculation */
261 assert(dictMode != ZSTD_dedicatedDictSearch);
262
263 /* reach end of unsorted candidates list */
264 while ( (matchIndex > unsortLimit)
265 && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK)
266 && (nbCandidates > 1) ) {
267 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted",
268 matchIndex);
269 *unsortedMark = previousCandidate; /* the unsortedMark becomes a reversed chain, to move up back to original position */
270 previousCandidate = matchIndex;
271 matchIndex = *nextCandidate;
272 nextCandidate = bt + 2*(matchIndex&btMask);
273 unsortedMark = bt + 2*(matchIndex&btMask) + 1;
274 nbCandidates --;
275 }
276
277 /* nullify last candidate if it's still unsorted
278 * simplification, detrimental to compression ratio, beneficial for speed */
279 if ( (matchIndex > unsortLimit)
280 && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) {
281 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u",
282 matchIndex);
283 *nextCandidate = *unsortedMark = 0;
284 }
285
286 /* batch sort stacked candidates */
287 matchIndex = previousCandidate;
288 while (matchIndex) { /* will end on matchIndex == 0 */
289 U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1;
290 U32 const nextCandidateIdx = *nextCandidateIdxPtr;
291 ZSTD_insertDUBT1(ms, matchIndex, iend,
292 nbCandidates, unsortLimit, dictMode);
293 matchIndex = nextCandidateIdx;
294 nbCandidates++;
295 }
296
297 /* find longest match */
298 { size_t commonLengthSmaller = 0, commonLengthLarger = 0;
299 const BYTE* const dictBase = ms->window.dictBase;
300 const U32 dictLimit = ms->window.dictLimit;
301 const BYTE* const dictEnd = dictBase + dictLimit;
302 const BYTE* const prefixStart = base + dictLimit;
303 U32* smallerPtr = bt + 2*(curr&btMask);
304 U32* largerPtr = bt + 2*(curr&btMask) + 1;
305 U32 matchEndIdx = curr + 8 + 1;
306 U32 dummy32; /* to be nullified at the end */
307 size_t bestLength = 0;
308
309 matchIndex = hashTable[h];
310 hashTable[h] = curr; /* Update Hash Table */
311
312 for (; nbCompares && (matchIndex > windowLow); --nbCompares) {
313 U32* const nextPtr = bt + 2*(matchIndex & btMask);
314 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
315 const BYTE* match;
316
317 if ((dictMode != ZSTD_extDict) || (matchIndex+matchLength >= dictLimit)) {
318 match = base + matchIndex;
319 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
320 } else {
321 match = dictBase + matchIndex;
322 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
323 if (matchIndex+matchLength >= dictLimit)
324 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
325 }
326
327 if (matchLength > bestLength) {
328 if (matchLength > matchEndIdx - matchIndex)
329 matchEndIdx = matchIndex + (U32)matchLength;
330 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(curr-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
331 bestLength = matchLength, *offsetPtr = STORE_OFFSET(curr - matchIndex);
332 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
333 if (dictMode == ZSTD_dictMatchState) {
334 nbCompares = 0; /* in addition to avoiding checking any
335 * further in this loop, make sure we
336 * skip checking in the dictionary. */
337 }
338 break; /* drop, to guarantee consistency (miss a little bit of compression) */
339 }
340 }
341
342 if (match[matchLength] < ip[matchLength]) {
343 /* match is smaller than current */
344 *smallerPtr = matchIndex; /* update smaller idx */
345 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
346 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
347 smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
348 matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
349 } else {
350 /* match is larger than current */
351 *largerPtr = matchIndex;
352 commonLengthLarger = matchLength;
353 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
354 largerPtr = nextPtr;
355 matchIndex = nextPtr[0];
356 } }
357
358 *smallerPtr = *largerPtr = 0;
359
360 assert(nbCompares <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
361 if (dictMode == ZSTD_dictMatchState && nbCompares) {
362 bestLength = ZSTD_DUBT_findBetterDictMatch(
363 ms, ip, iend,
364 offsetPtr, bestLength, nbCompares,
365 mls, dictMode);
366 }
367
368 assert(matchEndIdx > curr+8); /* ensure nextToUpdate is increased */
369 ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */
370 if (bestLength >= MINMATCH) {
371 U32 const mIndex = curr - (U32)STORED_OFFSET(*offsetPtr); (void)mIndex;
372 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
373 curr, (U32)bestLength, (U32)*offsetPtr, mIndex);
374 }
375 return bestLength;
376 }
377}
378
379
380/* ZSTD_BtFindBestMatch() : Tree updater, providing best match */
381FORCE_INLINE_TEMPLATE size_t
382ZSTD_BtFindBestMatch( ZSTD_matchState_t* ms,
383 const BYTE* const ip, const BYTE* const iLimit,
384 size_t* offsetPtr,
385 const U32 mls /* template */,
386 const ZSTD_dictMode_e dictMode)
387{
388 DEBUGLOG(7, "ZSTD_BtFindBestMatch");
389 if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */
390 ZSTD_updateDUBT(ms, ip, iLimit, mls);
391 return ZSTD_DUBT_findBestMatch(ms, ip, iLimit, offsetPtr, mls, dictMode);
392}
393
394/* *********************************
395* Dedicated dict search
396***********************************/
397
398void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const BYTE* const ip)
399{
400 const BYTE* const base = ms->window.base;
401 U32 const target = (U32)(ip - base);
402 U32* const hashTable = ms->hashTable;
403 U32* const chainTable = ms->chainTable;
404 U32 const chainSize = 1 << ms->cParams.chainLog;
405 U32 idx = ms->nextToUpdate;
406 U32 const minChain = chainSize < target - idx ? target - chainSize : idx;
407 U32 const bucketSize = 1 << ZSTD_LAZY_DDSS_BUCKET_LOG;
408 U32 const cacheSize = bucketSize - 1;
409 U32 const chainAttempts = (1 << ms->cParams.searchLog) - cacheSize;
410 U32 const chainLimit = chainAttempts > 255 ? 255 : chainAttempts;
411
412 /* We know the hashtable is oversized by a factor of `bucketSize`.
413 * We are going to temporarily pretend `bucketSize == 1`, keeping only a
414 * single entry. We will use the rest of the space to construct a temporary
415 * chaintable.
416 */
417 U32 const hashLog = ms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG;
418 U32* const tmpHashTable = hashTable;
419 U32* const tmpChainTable = hashTable + ((size_t)1 << hashLog);
420 U32 const tmpChainSize = (U32)((1 << ZSTD_LAZY_DDSS_BUCKET_LOG) - 1) << hashLog;
421 U32 const tmpMinChain = tmpChainSize < target ? target - tmpChainSize : idx;
422 U32 hashIdx;
423
424 assert(ms->cParams.chainLog <= 24);
425 assert(ms->cParams.hashLog > ms->cParams.chainLog);
426 assert(idx != 0);
427 assert(tmpMinChain <= minChain);
428
429 /* fill conventional hash table and conventional chain table */
430 for ( ; idx < target; idx++) {
431 U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch);
432 if (idx >= tmpMinChain) {
433 tmpChainTable[idx - tmpMinChain] = hashTable[h];
434 }
435 tmpHashTable[h] = idx;
436 }
437
438 /* sort chains into ddss chain table */
439 {
440 U32 chainPos = 0;
441 for (hashIdx = 0; hashIdx < (1U << hashLog); hashIdx++) {
442 U32 count;
443 U32 countBeyondMinChain = 0;
444 U32 i = tmpHashTable[hashIdx];
445 for (count = 0; i >= tmpMinChain && count < cacheSize; count++) {
446 /* skip through the chain to the first position that won't be
447 * in the hash cache bucket */
448 if (i < minChain) {
449 countBeyondMinChain++;
450 }
451 i = tmpChainTable[i - tmpMinChain];
452 }
453 if (count == cacheSize) {
454 for (count = 0; count < chainLimit;) {
455 if (i < minChain) {
456 if (!i || ++countBeyondMinChain > cacheSize) {
457 /* only allow pulling `cacheSize` number of entries
458 * into the cache or chainTable beyond `minChain`,
459 * to replace the entries pulled out of the
460 * chainTable into the cache. This lets us reach
461 * back further without increasing the total number
462 * of entries in the chainTable, guaranteeing the
463 * DDSS chain table will fit into the space
464 * allocated for the regular one. */
465 break;
466 }
467 }
468 chainTable[chainPos++] = i;
469 count++;
470 if (i < tmpMinChain) {
471 break;
472 }
473 i = tmpChainTable[i - tmpMinChain];
474 }
475 } else {
476 count = 0;
477 }
478 if (count) {
479 tmpHashTable[hashIdx] = ((chainPos - count) << 8) + count;
480 } else {
481 tmpHashTable[hashIdx] = 0;
482 }
483 }
484 assert(chainPos <= chainSize); /* I believe this is guaranteed... */
485 }
486
487 /* move chain pointers into the last entry of each hash bucket */
488 for (hashIdx = (1 << hashLog); hashIdx; ) {
489 U32 const bucketIdx = --hashIdx << ZSTD_LAZY_DDSS_BUCKET_LOG;
490 U32 const chainPackedPointer = tmpHashTable[hashIdx];
491 U32 i;
492 for (i = 0; i < cacheSize; i++) {
493 hashTable[bucketIdx + i] = 0;
494 }
495 hashTable[bucketIdx + bucketSize - 1] = chainPackedPointer;
496 }
497
498 /* fill the buckets of the hash table */
499 for (idx = ms->nextToUpdate; idx < target; idx++) {
500 U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch)
501 << ZSTD_LAZY_DDSS_BUCKET_LOG;
502 U32 i;
503 /* Shift hash cache down 1. */
504 for (i = cacheSize - 1; i; i--)
505 hashTable[h + i] = hashTable[h + i - 1];
506 hashTable[h] = idx;
507 }
508
509 ms->nextToUpdate = target;
510}
511
512/* Returns the longest match length found in the dedicated dict search structure.
513 * If none are longer than the argument ml, then ml will be returned.
514 */
515FORCE_INLINE_TEMPLATE
516size_t ZSTD_dedicatedDictSearch_lazy_search(size_t* offsetPtr, size_t ml, U32 nbAttempts,
517 const ZSTD_matchState_t* const dms,
518 const BYTE* const ip, const BYTE* const iLimit,
519 const BYTE* const prefixStart, const U32 curr,
520 const U32 dictLimit, const size_t ddsIdx) {
521 const U32 ddsLowestIndex = dms->window.dictLimit;
522 const BYTE* const ddsBase = dms->window.base;
523 const BYTE* const ddsEnd = dms->window.nextSrc;
524 const U32 ddsSize = (U32)(ddsEnd - ddsBase);
525 const U32 ddsIndexDelta = dictLimit - ddsSize;
526 const U32 bucketSize = (1 << ZSTD_LAZY_DDSS_BUCKET_LOG);
527 const U32 bucketLimit = nbAttempts < bucketSize - 1 ? nbAttempts : bucketSize - 1;
528 U32 ddsAttempt;
529 U32 matchIndex;
530
531 for (ddsAttempt = 0; ddsAttempt < bucketSize - 1; ddsAttempt++) {
532 PREFETCH_L1(ddsBase + dms->hashTable[ddsIdx + ddsAttempt]);
533 }
534
535 {
536 U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1];
537 U32 const chainIndex = chainPackedPointer >> 8;
538
539 PREFETCH_L1(&dms->chainTable[chainIndex]);
540 }
541
542 for (ddsAttempt = 0; ddsAttempt < bucketLimit; ddsAttempt++) {
543 size_t currentMl=0;
544 const BYTE* match;
545 matchIndex = dms->hashTable[ddsIdx + ddsAttempt];
546 match = ddsBase + matchIndex;
547
548 if (!matchIndex) {
549 return ml;
550 }
551
552 /* guaranteed by table construction */
553 (void)ddsLowestIndex;
554 assert(matchIndex >= ddsLowestIndex);
555 assert(match+4 <= ddsEnd);
556 if (MEM_read32(match) == MEM_read32(ip)) {
557 /* assumption : matchIndex <= dictLimit-4 (by table construction) */
558 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4;
559 }
560
561 /* save best solution */
562 if (currentMl > ml) {
563 ml = currentMl;
564 *offsetPtr = STORE_OFFSET(curr - (matchIndex + ddsIndexDelta));
565 if (ip+currentMl == iLimit) {
566 /* best possible, avoids read overflow on next attempt */
567 return ml;
568 }
569 }
570 }
571
572 {
573 U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1];
574 U32 chainIndex = chainPackedPointer >> 8;
575 U32 const chainLength = chainPackedPointer & 0xFF;
576 U32 const chainAttempts = nbAttempts - ddsAttempt;
577 U32 const chainLimit = chainAttempts > chainLength ? chainLength : chainAttempts;
578 U32 chainAttempt;
579
580 for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++) {
581 PREFETCH_L1(ddsBase + dms->chainTable[chainIndex + chainAttempt]);
582 }
583
584 for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++, chainIndex++) {
585 size_t currentMl=0;
586 const BYTE* match;
587 matchIndex = dms->chainTable[chainIndex];
588 match = ddsBase + matchIndex;
589
590 /* guaranteed by table construction */
591 assert(matchIndex >= ddsLowestIndex);
592 assert(match+4 <= ddsEnd);
593 if (MEM_read32(match) == MEM_read32(ip)) {
594 /* assumption : matchIndex <= dictLimit-4 (by table construction) */
595 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4;
596 }
597
598 /* save best solution */
599 if (currentMl > ml) {
600 ml = currentMl;
601 *offsetPtr = STORE_OFFSET(curr - (matchIndex + ddsIndexDelta));
602 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
603 }
604 }
605 }
606 return ml;
607}
608
609
610/* *********************************
611* Hash Chain
612***********************************/
613#define NEXT_IN_CHAIN(d, mask) chainTable[(d) & (mask)]
614
615/* Update chains up to ip (excluded)
616 Assumption : always within prefix (i.e. not within extDict) */
617FORCE_INLINE_TEMPLATE U32 ZSTD_insertAndFindFirstIndex_internal(
618 ZSTD_matchState_t* ms,
619 const ZSTD_compressionParameters* const cParams,
620 const BYTE* ip, U32 const mls)
621{
622 U32* const hashTable = ms->hashTable;
623 const U32 hashLog = cParams->hashLog;
624 U32* const chainTable = ms->chainTable;
625 const U32 chainMask = (1 << cParams->chainLog) - 1;
626 const BYTE* const base = ms->window.base;
627 const U32 target = (U32)(ip - base);
628 U32 idx = ms->nextToUpdate;
629
630 while(idx < target) { /* catch up */
631 size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
632 NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
633 hashTable[h] = idx;
634 idx++;
635 }
636
637 ms->nextToUpdate = target;
638 return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
639}
640
641U32 ZSTD_insertAndFindFirstIndex(ZSTD_matchState_t* ms, const BYTE* ip) {
642 const ZSTD_compressionParameters* const cParams = &ms->cParams;
643 return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, ms->cParams.minMatch);
644}
645
646/* inlining is important to hardwire a hot branch (template emulation) */
647FORCE_INLINE_TEMPLATE
648size_t ZSTD_HcFindBestMatch(
649 ZSTD_matchState_t* ms,
650 const BYTE* const ip, const BYTE* const iLimit,
651 size_t* offsetPtr,
652 const U32 mls, const ZSTD_dictMode_e dictMode)
653{
654 const ZSTD_compressionParameters* const cParams = &ms->cParams;
655 U32* const chainTable = ms->chainTable;
656 const U32 chainSize = (1 << cParams->chainLog);
657 const U32 chainMask = chainSize-1;
658 const BYTE* const base = ms->window.base;
659 const BYTE* const dictBase = ms->window.dictBase;
660 const U32 dictLimit = ms->window.dictLimit;
661 const BYTE* const prefixStart = base + dictLimit;
662 const BYTE* const dictEnd = dictBase + dictLimit;
663 const U32 curr = (U32)(ip-base);
664 const U32 maxDistance = 1U << cParams->windowLog;
665 const U32 lowestValid = ms->window.lowLimit;
666 const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
667 const U32 isDictionary = (ms->loadedDictEnd != 0);
668 const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
669 const U32 minChain = curr > chainSize ? curr - chainSize : 0;
670 U32 nbAttempts = 1U << cParams->searchLog;
671 size_t ml=4-1;
672
673 const ZSTD_matchState_t* const dms = ms->dictMatchState;
674 const U32 ddsHashLog = dictMode == ZSTD_dedicatedDictSearch
675 ? dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG : 0;
676 const size_t ddsIdx = dictMode == ZSTD_dedicatedDictSearch
677 ? ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG : 0;
678
679 U32 matchIndex;
680
681 if (dictMode == ZSTD_dedicatedDictSearch) {
682 const U32* entry = &dms->hashTable[ddsIdx];
683 PREFETCH_L1(entry);
684 }
685
686 /* HC4 match finder */
687 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls);
688
689 for ( ; (matchIndex>=lowLimit) & (nbAttempts>0) ; nbAttempts--) {
690 size_t currentMl=0;
691 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
692 const BYTE* const match = base + matchIndex;
693 assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
694 if (match[ml] == ip[ml]) /* potentially better */
695 currentMl = ZSTD_count(ip, match, iLimit);
696 } else {
697 const BYTE* const match = dictBase + matchIndex;
698 assert(match+4 <= dictEnd);
699 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
700 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
701 }
702
703 /* save best solution */
704 if (currentMl > ml) {
705 ml = currentMl;
706 *offsetPtr = STORE_OFFSET(curr - matchIndex);
707 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
708 }
709
710 if (matchIndex <= minChain) break;
711 matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
712 }
713
714 assert(nbAttempts <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
715 if (dictMode == ZSTD_dedicatedDictSearch) {
716 ml = ZSTD_dedicatedDictSearch_lazy_search(offsetPtr, ml, nbAttempts, dms,
717 ip, iLimit, prefixStart, curr, dictLimit, ddsIdx);
718 } else if (dictMode == ZSTD_dictMatchState) {
719 const U32* const dmsChainTable = dms->chainTable;
720 const U32 dmsChainSize = (1 << dms->cParams.chainLog);
721 const U32 dmsChainMask = dmsChainSize - 1;
722 const U32 dmsLowestIndex = dms->window.dictLimit;
723 const BYTE* const dmsBase = dms->window.base;
724 const BYTE* const dmsEnd = dms->window.nextSrc;
725 const U32 dmsSize = (U32)(dmsEnd - dmsBase);
726 const U32 dmsIndexDelta = dictLimit - dmsSize;
727 const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0;
728
729 matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)];
730
731 for ( ; (matchIndex>=dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) {
732 size_t currentMl=0;
733 const BYTE* const match = dmsBase + matchIndex;
734 assert(match+4 <= dmsEnd);
735 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
736 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
737
738 /* save best solution */
739 if (currentMl > ml) {
740 ml = currentMl;
741 assert(curr > matchIndex + dmsIndexDelta);
742 *offsetPtr = STORE_OFFSET(curr - (matchIndex + dmsIndexDelta));
743 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
744 }
745
746 if (matchIndex <= dmsMinChain) break;
747
748 matchIndex = dmsChainTable[matchIndex & dmsChainMask];
749 }
750 }
751
752 return ml;
753}
754
755/* *********************************
756* (SIMD) Row-based matchfinder
757***********************************/
758/* Constants for row-based hash */
759#define ZSTD_ROW_HASH_TAG_OFFSET 16 /* byte offset of hashes in the match state's tagTable from the beginning of a row */
760#define ZSTD_ROW_HASH_TAG_BITS 8 /* nb bits to use for the tag */
761#define ZSTD_ROW_HASH_TAG_MASK ((1u << ZSTD_ROW_HASH_TAG_BITS) - 1)
762#define ZSTD_ROW_HASH_MAX_ENTRIES 64 /* absolute maximum number of entries per row, for all configurations */
763
764#define ZSTD_ROW_HASH_CACHE_MASK (ZSTD_ROW_HASH_CACHE_SIZE - 1)
765
766typedef U64 ZSTD_VecMask; /* Clarifies when we are interacting with a U64 representing a mask of matches */
767
768/* ZSTD_VecMask_next():
769 * Starting from the LSB, returns the idx of the next non-zero bit.
770 * Basically counting the nb of trailing zeroes.
771 */
772static U32 ZSTD_VecMask_next(ZSTD_VecMask val) {
773 assert(val != 0);
774# if (defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))))
775 if (sizeof(size_t) == 4) {
776 U32 mostSignificantWord = (U32)(val >> 32);
777 U32 leastSignificantWord = (U32)val;
778 if (leastSignificantWord == 0) {
779 return 32 + (U32)__builtin_ctz(mostSignificantWord);
780 } else {
781 return (U32)__builtin_ctz(leastSignificantWord);
782 }
783 } else {
784 return (U32)__builtin_ctzll(val);
785 }
786# else
787 /* Software ctz version: http://aggregate.org/MAGIC/#Trailing%20Zero%20Count
788 * and: https://stackoverflow.com/questions/2709430/count-number-of-bits-in-a-64-bit-long-big-integer
789 */
790 val = ~val & (val - 1ULL); /* Lowest set bit mask */
791 val = val - ((val >> 1) & 0x5555555555555555);
792 val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL);
793 return (U32)((((val + (val >> 4)) & 0xF0F0F0F0F0F0F0FULL) * 0x101010101010101ULL) >> 56);
794# endif
795}
796
797/* ZSTD_rotateRight_*():
798 * Rotates a bitfield to the right by "count" bits.
799 * https://en.wikipedia.org/w/index.php?title=Circular_shift&oldid=991635599#Implementing_circular_shifts
800 */
801FORCE_INLINE_TEMPLATE
802U64 ZSTD_rotateRight_U64(U64 const value, U32 count) {
803 assert(count < 64);
804 count &= 0x3F; /* for fickle pattern recognition */
805 return (value >> count) | (U64)(value << ((0U - count) & 0x3F));
806}
807
808FORCE_INLINE_TEMPLATE
809U32 ZSTD_rotateRight_U32(U32 const value, U32 count) {
810 assert(count < 32);
811 count &= 0x1F; /* for fickle pattern recognition */
812 return (value >> count) | (U32)(value << ((0U - count) & 0x1F));
813}
814
815FORCE_INLINE_TEMPLATE
816U16 ZSTD_rotateRight_U16(U16 const value, U32 count) {
817 assert(count < 16);
818 count &= 0x0F; /* for fickle pattern recognition */
819 return (value >> count) | (U16)(value << ((0U - count) & 0x0F));
820}
821
822/* ZSTD_row_nextIndex():
823 * Returns the next index to insert at within a tagTable row, and updates the "head"
824 * value to reflect the update. Essentially cycles backwards from [0, {entries per row})
825 */
826FORCE_INLINE_TEMPLATE U32 ZSTD_row_nextIndex(BYTE* const tagRow, U32 const rowMask) {
827 U32 const next = (*tagRow - 1) & rowMask;
828 *tagRow = (BYTE)next;
829 return next;
830}
831
832/* ZSTD_isAligned():
833 * Checks that a pointer is aligned to "align" bytes which must be a power of 2.
834 */
835MEM_STATIC int ZSTD_isAligned(void const* ptr, size_t align) {
836 assert((align & (align - 1)) == 0);
837 return (((size_t)ptr) & (align - 1)) == 0;
838}
839
840/* ZSTD_row_prefetch():
841 * Performs prefetching for the hashTable and tagTable at a given row.
842 */
843FORCE_INLINE_TEMPLATE void ZSTD_row_prefetch(U32 const* hashTable, U16 const* tagTable, U32 const relRow, U32 const rowLog) {
844 PREFETCH_L1(hashTable + relRow);
845 if (rowLog >= 5) {
846 PREFETCH_L1(hashTable + relRow + 16);
847 /* Note: prefetching more of the hash table does not appear to be beneficial for 128-entry rows */
848 }
849 PREFETCH_L1(tagTable + relRow);
850 if (rowLog == 6) {
851 PREFETCH_L1(tagTable + relRow + 32);
852 }
853 assert(rowLog == 4 || rowLog == 5 || rowLog == 6);
854 assert(ZSTD_isAligned(hashTable + relRow, 64)); /* prefetched hash row always 64-byte aligned */
855 assert(ZSTD_isAligned(tagTable + relRow, (size_t)1 << rowLog)); /* prefetched tagRow sits on correct multiple of bytes (32,64,128) */
856}
857
858/* ZSTD_row_fillHashCache():
859 * Fill up the hash cache starting at idx, prefetching up to ZSTD_ROW_HASH_CACHE_SIZE entries,
860 * but not beyond iLimit.
861 */
862FORCE_INLINE_TEMPLATE void ZSTD_row_fillHashCache(ZSTD_matchState_t* ms, const BYTE* base,
863 U32 const rowLog, U32 const mls,
864 U32 idx, const BYTE* const iLimit)
865{
866 U32 const* const hashTable = ms->hashTable;
867 U16 const* const tagTable = ms->tagTable;
868 U32 const hashLog = ms->rowHashLog;
869 U32 const maxElemsToPrefetch = (base + idx) > iLimit ? 0 : (U32)(iLimit - (base + idx) + 1);
870 U32 const lim = idx + MIN(ZSTD_ROW_HASH_CACHE_SIZE, maxElemsToPrefetch);
871
872 for (; idx < lim; ++idx) {
873 U32 const hash = (U32)ZSTD_hashPtr(base + idx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
874 U32 const row = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
875 ZSTD_row_prefetch(hashTable, tagTable, row, rowLog);
876 ms->hashCache[idx & ZSTD_ROW_HASH_CACHE_MASK] = hash;
877 }
878
879 DEBUGLOG(6, "ZSTD_row_fillHashCache(): [%u %u %u %u %u %u %u %u]", ms->hashCache[0], ms->hashCache[1],
880 ms->hashCache[2], ms->hashCache[3], ms->hashCache[4],
881 ms->hashCache[5], ms->hashCache[6], ms->hashCache[7]);
882}
883
884/* ZSTD_row_nextCachedHash():
885 * Returns the hash of base + idx, and replaces the hash in the hash cache with the byte at
886 * base + idx + ZSTD_ROW_HASH_CACHE_SIZE. Also prefetches the appropriate rows from hashTable and tagTable.
887 */
888FORCE_INLINE_TEMPLATE U32 ZSTD_row_nextCachedHash(U32* cache, U32 const* hashTable,
889 U16 const* tagTable, BYTE const* base,
890 U32 idx, U32 const hashLog,
891 U32 const rowLog, U32 const mls)
892{
893 U32 const newHash = (U32)ZSTD_hashPtr(base+idx+ZSTD_ROW_HASH_CACHE_SIZE, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
894 U32 const row = (newHash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
895 ZSTD_row_prefetch(hashTable, tagTable, row, rowLog);
896 { U32 const hash = cache[idx & ZSTD_ROW_HASH_CACHE_MASK];
897 cache[idx & ZSTD_ROW_HASH_CACHE_MASK] = newHash;
898 return hash;
899 }
900}
901
902/* ZSTD_row_update_internalImpl():
903 * Updates the hash table with positions starting from updateStartIdx until updateEndIdx.
904 */
905FORCE_INLINE_TEMPLATE void ZSTD_row_update_internalImpl(ZSTD_matchState_t* ms,
906 U32 updateStartIdx, U32 const updateEndIdx,
907 U32 const mls, U32 const rowLog,
908 U32 const rowMask, U32 const useCache)
909{
910 U32* const hashTable = ms->hashTable;
911 U16* const tagTable = ms->tagTable;
912 U32 const hashLog = ms->rowHashLog;
913 const BYTE* const base = ms->window.base;
914
915 DEBUGLOG(6, "ZSTD_row_update_internalImpl(): updateStartIdx=%u, updateEndIdx=%u", updateStartIdx, updateEndIdx);
916 for (; updateStartIdx < updateEndIdx; ++updateStartIdx) {
917 U32 const hash = useCache ? ZSTD_row_nextCachedHash(ms->hashCache, hashTable, tagTable, base, updateStartIdx, hashLog, rowLog, mls)
918 : (U32)ZSTD_hashPtr(base + updateStartIdx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
919 U32 const relRow = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
920 U32* const row = hashTable + relRow;
921 BYTE* tagRow = (BYTE*)(tagTable + relRow); /* Though tagTable is laid out as a table of U16, each tag is only 1 byte.
922 Explicit cast allows us to get exact desired position within each row */
923 U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
924
925 assert(hash == ZSTD_hashPtr(base + updateStartIdx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls));
926 ((BYTE*)tagRow)[pos + ZSTD_ROW_HASH_TAG_OFFSET] = hash & ZSTD_ROW_HASH_TAG_MASK;
927 row[pos] = updateStartIdx;
928 }
929}
930
931/* ZSTD_row_update_internal():
932 * Inserts the byte at ip into the appropriate position in the hash table, and updates ms->nextToUpdate.
933 * Skips sections of long matches as is necessary.
934 */
935FORCE_INLINE_TEMPLATE void ZSTD_row_update_internal(ZSTD_matchState_t* ms, const BYTE* ip,
936 U32 const mls, U32 const rowLog,
937 U32 const rowMask, U32 const useCache)
938{
939 U32 idx = ms->nextToUpdate;
940 const BYTE* const base = ms->window.base;
941 const U32 target = (U32)(ip - base);
942 const U32 kSkipThreshold = 384;
943 const U32 kMaxMatchStartPositionsToUpdate = 96;
944 const U32 kMaxMatchEndPositionsToUpdate = 32;
945
946 if (useCache) {
947 /* Only skip positions when using hash cache, i.e.
948 * if we are loading a dict, don't skip anything.
949 * If we decide to skip, then we only update a set number
950 * of positions at the beginning and end of the match.
951 */
952 if (UNLIKELY(target - idx > kSkipThreshold)) {
953 U32 const bound = idx + kMaxMatchStartPositionsToUpdate;
954 ZSTD_row_update_internalImpl(ms, idx, bound, mls, rowLog, rowMask, useCache);
955 idx = target - kMaxMatchEndPositionsToUpdate;
956 ZSTD_row_fillHashCache(ms, base, rowLog, mls, idx, ip+1);
957 }
958 }
959 assert(target >= idx);
960 ZSTD_row_update_internalImpl(ms, idx, target, mls, rowLog, rowMask, useCache);
961 ms->nextToUpdate = target;
962}
963
964/* ZSTD_row_update():
965 * External wrapper for ZSTD_row_update_internal(). Used for filling the hashtable during dictionary
966 * processing.
967 */
968void ZSTD_row_update(ZSTD_matchState_t* const ms, const BYTE* ip) {
969 const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
970 const U32 rowMask = (1u << rowLog) - 1;
971 const U32 mls = MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */);
972
973 DEBUGLOG(5, "ZSTD_row_update(), rowLog=%u", rowLog);
974 ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 0 /* dont use cache */);
975}
976
977#if defined(ZSTD_ARCH_X86_SSE2)
978FORCE_INLINE_TEMPLATE ZSTD_VecMask
979ZSTD_row_getSSEMask(int nbChunks, const BYTE* const src, const BYTE tag, const U32 head)
980{
981 const __m128i comparisonMask = _mm_set1_epi8((char)tag);
982 int matches[4] = {0};
983 int i;
984 assert(nbChunks == 1 || nbChunks == 2 || nbChunks == 4);
985 for (i=0; i<nbChunks; i++) {
986 const __m128i chunk = _mm_loadu_si128((const __m128i*)(const void*)(src + 16*i));
987 const __m128i equalMask = _mm_cmpeq_epi8(chunk, comparisonMask);
988 matches[i] = _mm_movemask_epi8(equalMask);
989 }
990 if (nbChunks == 1) return ZSTD_rotateRight_U16((U16)matches[0], head);
991 if (nbChunks == 2) return ZSTD_rotateRight_U32((U32)matches[1] << 16 | (U32)matches[0], head);
992 assert(nbChunks == 4);
993 return ZSTD_rotateRight_U64((U64)matches[3] << 48 | (U64)matches[2] << 32 | (U64)matches[1] << 16 | (U64)matches[0], head);
994}
995#endif
996
997/* Returns a ZSTD_VecMask (U32) that has the nth bit set to 1 if the newly-computed "tag" matches
998 * the hash at the nth position in a row of the tagTable.
999 * Each row is a circular buffer beginning at the value of "head". So we must rotate the "matches" bitfield
1000 * to match up with the actual layout of the entries within the hashTable */
1001FORCE_INLINE_TEMPLATE ZSTD_VecMask
1002ZSTD_row_getMatchMask(const BYTE* const tagRow, const BYTE tag, const U32 head, const U32 rowEntries)
1003{
1004 const BYTE* const src = tagRow + ZSTD_ROW_HASH_TAG_OFFSET;
1005 assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64);
1006 assert(rowEntries <= ZSTD_ROW_HASH_MAX_ENTRIES);
1007
1008#if defined(ZSTD_ARCH_X86_SSE2)
1009
1010 return ZSTD_row_getSSEMask(rowEntries / 16, src, tag, head);
1011
1012#else /* SW or NEON-LE */
1013
1014# if defined(ZSTD_ARCH_ARM_NEON)
1015 /* This NEON path only works for little endian - otherwise use SWAR below */
1016 if (MEM_isLittleEndian()) {
1017 if (rowEntries == 16) {
1018 const uint8x16_t chunk = vld1q_u8(src);
1019 const uint16x8_t equalMask = vreinterpretq_u16_u8(vceqq_u8(chunk, vdupq_n_u8(tag)));
1020 const uint16x8_t t0 = vshlq_n_u16(equalMask, 7);
1021 const uint32x4_t t1 = vreinterpretq_u32_u16(vsriq_n_u16(t0, t0, 14));
1022 const uint64x2_t t2 = vreinterpretq_u64_u32(vshrq_n_u32(t1, 14));
1023 const uint8x16_t t3 = vreinterpretq_u8_u64(vsraq_n_u64(t2, t2, 28));
1024 const U16 hi = (U16)vgetq_lane_u8(t3, 8);
1025 const U16 lo = (U16)vgetq_lane_u8(t3, 0);
1026 return ZSTD_rotateRight_U16((hi << 8) | lo, head);
1027 } else if (rowEntries == 32) {
1028 const uint16x8x2_t chunk = vld2q_u16((const U16*)(const void*)src);
1029 const uint8x16_t chunk0 = vreinterpretq_u8_u16(chunk.val[0]);
1030 const uint8x16_t chunk1 = vreinterpretq_u8_u16(chunk.val[1]);
1031 const uint8x16_t equalMask0 = vceqq_u8(chunk0, vdupq_n_u8(tag));
1032 const uint8x16_t equalMask1 = vceqq_u8(chunk1, vdupq_n_u8(tag));
1033 const int8x8_t pack0 = vqmovn_s16(vreinterpretq_s16_u8(equalMask0));
1034 const int8x8_t pack1 = vqmovn_s16(vreinterpretq_s16_u8(equalMask1));
1035 const uint8x8_t t0 = vreinterpret_u8_s8(pack0);
1036 const uint8x8_t t1 = vreinterpret_u8_s8(pack1);
1037 const uint8x8_t t2 = vsri_n_u8(t1, t0, 2);
1038 const uint8x8x2_t t3 = vuzp_u8(t2, t0);
1039 const uint8x8_t t4 = vsri_n_u8(t3.val[1], t3.val[0], 4);
1040 const U32 matches = vget_lane_u32(vreinterpret_u32_u8(t4), 0);
1041 return ZSTD_rotateRight_U32(matches, head);
1042 } else { /* rowEntries == 64 */
1043 const uint8x16x4_t chunk = vld4q_u8(src);
1044 const uint8x16_t dup = vdupq_n_u8(tag);
1045 const uint8x16_t cmp0 = vceqq_u8(chunk.val[0], dup);
1046 const uint8x16_t cmp1 = vceqq_u8(chunk.val[1], dup);
1047 const uint8x16_t cmp2 = vceqq_u8(chunk.val[2], dup);
1048 const uint8x16_t cmp3 = vceqq_u8(chunk.val[3], dup);
1049
1050 const uint8x16_t t0 = vsriq_n_u8(cmp1, cmp0, 1);
1051 const uint8x16_t t1 = vsriq_n_u8(cmp3, cmp2, 1);
1052 const uint8x16_t t2 = vsriq_n_u8(t1, t0, 2);
1053 const uint8x16_t t3 = vsriq_n_u8(t2, t2, 4);
1054 const uint8x8_t t4 = vshrn_n_u16(vreinterpretq_u16_u8(t3), 4);
1055 const U64 matches = vget_lane_u64(vreinterpret_u64_u8(t4), 0);
1056 return ZSTD_rotateRight_U64(matches, head);
1057 }
1058 }
1059# endif /* ZSTD_ARCH_ARM_NEON */
1060 /* SWAR */
1061 { const size_t chunkSize = sizeof(size_t);
1062 const size_t shiftAmount = ((chunkSize * 8) - chunkSize);
1063 const size_t xFF = ~((size_t)0);
1064 const size_t x01 = xFF / 0xFF;
1065 const size_t x80 = x01 << 7;
1066 const size_t splatChar = tag * x01;
1067 ZSTD_VecMask matches = 0;
1068 int i = rowEntries - chunkSize;
1069 assert((sizeof(size_t) == 4) || (sizeof(size_t) == 8));
1070 if (MEM_isLittleEndian()) { /* runtime check so have two loops */
1071 const size_t extractMagic = (xFF / 0x7F) >> chunkSize;
1072 do {
1073 size_t chunk = MEM_readST(&src[i]);
1074 chunk ^= splatChar;
1075 chunk = (((chunk | x80) - x01) | chunk) & x80;
1076 matches <<= chunkSize;
1077 matches |= (chunk * extractMagic) >> shiftAmount;
1078 i -= chunkSize;
1079 } while (i >= 0);
1080 } else { /* big endian: reverse bits during extraction */
1081 const size_t msb = xFF ^ (xFF >> 1);
1082 const size_t extractMagic = (msb / 0x1FF) | msb;
1083 do {
1084 size_t chunk = MEM_readST(&src[i]);
1085 chunk ^= splatChar;
1086 chunk = (((chunk | x80) - x01) | chunk) & x80;
1087 matches <<= chunkSize;
1088 matches |= ((chunk >> 7) * extractMagic) >> shiftAmount;
1089 i -= chunkSize;
1090 } while (i >= 0);
1091 }
1092 matches = ~matches;
1093 if (rowEntries == 16) {
1094 return ZSTD_rotateRight_U16((U16)matches, head);
1095 } else if (rowEntries == 32) {
1096 return ZSTD_rotateRight_U32((U32)matches, head);
1097 } else {
1098 return ZSTD_rotateRight_U64((U64)matches, head);
1099 }
1100 }
1101#endif
1102}
1103
1104/* The high-level approach of the SIMD row based match finder is as follows:
1105 * - Figure out where to insert the new entry:
1106 * - Generate a hash from a byte along with an additional 1-byte "short hash". The additional byte is our "tag"
1107 * - The hashTable is effectively split into groups or "rows" of 16 or 32 entries of U32, and the hash determines
1108 * which row to insert into.
1109 * - Determine the correct position within the row to insert the entry into. Each row of 16 or 32 can
1110 * be considered as a circular buffer with a "head" index that resides in the tagTable.
1111 * - Also insert the "tag" into the equivalent row and position in the tagTable.
1112 * - Note: The tagTable has 17 or 33 1-byte entries per row, due to 16 or 32 tags, and 1 "head" entry.
1113 * The 17 or 33 entry rows are spaced out to occur every 32 or 64 bytes, respectively,
1114 * for alignment/performance reasons, leaving some bytes unused.
1115 * - Use SIMD to efficiently compare the tags in the tagTable to the 1-byte "short hash" and
1116 * generate a bitfield that we can cycle through to check the collisions in the hash table.
1117 * - Pick the longest match.
1118 */
1119FORCE_INLINE_TEMPLATE
1120size_t ZSTD_RowFindBestMatch(
1121 ZSTD_matchState_t* ms,
1122 const BYTE* const ip, const BYTE* const iLimit,
1123 size_t* offsetPtr,
1124 const U32 mls, const ZSTD_dictMode_e dictMode,
1125 const U32 rowLog)
1126{
1127 U32* const hashTable = ms->hashTable;
1128 U16* const tagTable = ms->tagTable;
1129 U32* const hashCache = ms->hashCache;
1130 const U32 hashLog = ms->rowHashLog;
1131 const ZSTD_compressionParameters* const cParams = &ms->cParams;
1132 const BYTE* const base = ms->window.base;
1133 const BYTE* const dictBase = ms->window.dictBase;
1134 const U32 dictLimit = ms->window.dictLimit;
1135 const BYTE* const prefixStart = base + dictLimit;
1136 const BYTE* const dictEnd = dictBase + dictLimit;
1137 const U32 curr = (U32)(ip-base);
1138 const U32 maxDistance = 1U << cParams->windowLog;
1139 const U32 lowestValid = ms->window.lowLimit;
1140 const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
1141 const U32 isDictionary = (ms->loadedDictEnd != 0);
1142 const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
1143 const U32 rowEntries = (1U << rowLog);
1144 const U32 rowMask = rowEntries - 1;
1145 const U32 cappedSearchLog = MIN(cParams->searchLog, rowLog); /* nb of searches is capped at nb entries per row */
1146 U32 nbAttempts = 1U << cappedSearchLog;
1147 size_t ml=4-1;
1148
1149 /* DMS/DDS variables that may be referenced laster */
1150 const ZSTD_matchState_t* const dms = ms->dictMatchState;
1151
1152 /* Initialize the following variables to satisfy static analyzer */
1153 size_t ddsIdx = 0;
1154 U32 ddsExtraAttempts = 0; /* cctx hash tables are limited in searches, but allow extra searches into DDS */
1155 U32 dmsTag = 0;
1156 U32* dmsRow = NULL;
1157 BYTE* dmsTagRow = NULL;
1158
1159 if (dictMode == ZSTD_dedicatedDictSearch) {
1160 const U32 ddsHashLog = dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG;
1161 { /* Prefetch DDS hashtable entry */
1162 ddsIdx = ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG;
1163 PREFETCH_L1(&dms->hashTable[ddsIdx]);
1164 }
1165 ddsExtraAttempts = cParams->searchLog > rowLog ? 1U << (cParams->searchLog - rowLog) : 0;
1166 }
1167
1168 if (dictMode == ZSTD_dictMatchState) {
1169 /* Prefetch DMS rows */
1170 U32* const dmsHashTable = dms->hashTable;
1171 U16* const dmsTagTable = dms->tagTable;
1172 U32 const dmsHash = (U32)ZSTD_hashPtr(ip, dms->rowHashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
1173 U32 const dmsRelRow = (dmsHash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
1174 dmsTag = dmsHash & ZSTD_ROW_HASH_TAG_MASK;
1175 dmsTagRow = (BYTE*)(dmsTagTable + dmsRelRow);
1176 dmsRow = dmsHashTable + dmsRelRow;
1177 ZSTD_row_prefetch(dmsHashTable, dmsTagTable, dmsRelRow, rowLog);
1178 }
1179
1180 /* Update the hashTable and tagTable up to (but not including) ip */
1181 ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 1 /* useCache */);
1182 { /* Get the hash for ip, compute the appropriate row */
1183 U32 const hash = ZSTD_row_nextCachedHash(hashCache, hashTable, tagTable, base, curr, hashLog, rowLog, mls);
1184 U32 const relRow = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
1185 U32 const tag = hash & ZSTD_ROW_HASH_TAG_MASK;
1186 U32* const row = hashTable + relRow;
1187 BYTE* tagRow = (BYTE*)(tagTable + relRow);
1188 U32 const head = *tagRow & rowMask;
1189 U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES];
1190 size_t numMatches = 0;
1191 size_t currMatch = 0;
1192 ZSTD_VecMask matches = ZSTD_row_getMatchMask(tagRow, (BYTE)tag, head, rowEntries);
1193
1194 /* Cycle through the matches and prefetch */
1195 for (; (matches > 0) && (nbAttempts > 0); --nbAttempts, matches &= (matches - 1)) {
1196 U32 const matchPos = (head + ZSTD_VecMask_next(matches)) & rowMask;
1197 U32 const matchIndex = row[matchPos];
1198 assert(numMatches < rowEntries);
1199 if (matchIndex < lowLimit)
1200 break;
1201 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
1202 PREFETCH_L1(base + matchIndex);
1203 } else {
1204 PREFETCH_L1(dictBase + matchIndex);
1205 }
1206 matchBuffer[numMatches++] = matchIndex;
1207 }
1208
1209 /* Speed opt: insert current byte into hashtable too. This allows us to avoid one iteration of the loop
1210 in ZSTD_row_update_internal() at the next search. */
1211 {
1212 U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
1213 tagRow[pos + ZSTD_ROW_HASH_TAG_OFFSET] = (BYTE)tag;
1214 row[pos] = ms->nextToUpdate++;
1215 }
1216
1217 /* Return the longest match */
1218 for (; currMatch < numMatches; ++currMatch) {
1219 U32 const matchIndex = matchBuffer[currMatch];
1220 size_t currentMl=0;
1221 assert(matchIndex < curr);
1222 assert(matchIndex >= lowLimit);
1223
1224 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
1225 const BYTE* const match = base + matchIndex;
1226 assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
1227 if (match[ml] == ip[ml]) /* potentially better */
1228 currentMl = ZSTD_count(ip, match, iLimit);
1229 } else {
1230 const BYTE* const match = dictBase + matchIndex;
1231 assert(match+4 <= dictEnd);
1232 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
1233 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
1234 }
1235
1236 /* Save best solution */
1237 if (currentMl > ml) {
1238 ml = currentMl;
1239 *offsetPtr = STORE_OFFSET(curr - matchIndex);
1240 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
1241 }
1242 }
1243 }
1244
1245 assert(nbAttempts <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
1246 if (dictMode == ZSTD_dedicatedDictSearch) {
1247 ml = ZSTD_dedicatedDictSearch_lazy_search(offsetPtr, ml, nbAttempts + ddsExtraAttempts, dms,
1248 ip, iLimit, prefixStart, curr, dictLimit, ddsIdx);
1249 } else if (dictMode == ZSTD_dictMatchState) {
1250 /* TODO: Measure and potentially add prefetching to DMS */
1251 const U32 dmsLowestIndex = dms->window.dictLimit;
1252 const BYTE* const dmsBase = dms->window.base;
1253 const BYTE* const dmsEnd = dms->window.nextSrc;
1254 const U32 dmsSize = (U32)(dmsEnd - dmsBase);
1255 const U32 dmsIndexDelta = dictLimit - dmsSize;
1256
1257 { U32 const head = *dmsTagRow & rowMask;
1258 U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES];
1259 size_t numMatches = 0;
1260 size_t currMatch = 0;
1261 ZSTD_VecMask matches = ZSTD_row_getMatchMask(dmsTagRow, (BYTE)dmsTag, head, rowEntries);
1262
1263 for (; (matches > 0) && (nbAttempts > 0); --nbAttempts, matches &= (matches - 1)) {
1264 U32 const matchPos = (head + ZSTD_VecMask_next(matches)) & rowMask;
1265 U32 const matchIndex = dmsRow[matchPos];
1266 if (matchIndex < dmsLowestIndex)
1267 break;
1268 PREFETCH_L1(dmsBase + matchIndex);
1269 matchBuffer[numMatches++] = matchIndex;
1270 }
1271
1272 /* Return the longest match */
1273 for (; currMatch < numMatches; ++currMatch) {
1274 U32 const matchIndex = matchBuffer[currMatch];
1275 size_t currentMl=0;
1276 assert(matchIndex >= dmsLowestIndex);
1277 assert(matchIndex < curr);
1278
1279 { const BYTE* const match = dmsBase + matchIndex;
1280 assert(match+4 <= dmsEnd);
1281 if (MEM_read32(match) == MEM_read32(ip))
1282 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
1283 }
1284
1285 if (currentMl > ml) {
1286 ml = currentMl;
1287 assert(curr > matchIndex + dmsIndexDelta);
1288 *offsetPtr = STORE_OFFSET(curr - (matchIndex + dmsIndexDelta));
1289 if (ip+currentMl == iLimit) break;
1290 }
1291 }
1292 }
1293 }
1294 return ml;
1295}
1296
1297
1298/*
1299 * Generate search functions templated on (dictMode, mls, rowLog).
1300 * These functions are outlined for code size & compilation time.
1301 * ZSTD_searchMax() dispatches to the correct implementation function.
1302 *
1303 * TODO: The start of the search function involves loading and calculating a
1304 * bunch of constants from the ZSTD_matchState_t. These computations could be
1305 * done in an initialization function, and saved somewhere in the match state.
1306 * Then we could pass a pointer to the saved state instead of the match state,
1307 * and avoid duplicate computations.
1308 *
1309 * TODO: Move the match re-winding into searchMax. This improves compression
1310 * ratio, and unlocks further simplifications with the next TODO.
1311 *
1312 * TODO: Try moving the repcode search into searchMax. After the re-winding
1313 * and repcode search are in searchMax, there is no more logic in the match
1314 * finder loop that requires knowledge about the dictMode. So we should be
1315 * able to avoid force inlining it, and we can join the extDict loop with
1316 * the single segment loop. It should go in searchMax instead of its own
1317 * function to avoid having multiple virtual function calls per search.
1318 */
1319
1320#define ZSTD_BT_SEARCH_FN(dictMode, mls) ZSTD_BtFindBestMatch_##dictMode##_##mls
1321#define ZSTD_HC_SEARCH_FN(dictMode, mls) ZSTD_HcFindBestMatch_##dictMode##_##mls
1322#define ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog) ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog
1323
1324#define ZSTD_SEARCH_FN_ATTRS FORCE_NOINLINE
1325
1326#define GEN_ZSTD_BT_SEARCH_FN(dictMode, mls) \
1327 ZSTD_SEARCH_FN_ATTRS size_t ZSTD_BT_SEARCH_FN(dictMode, mls)( \
1328 ZSTD_matchState_t* ms, \
1329 const BYTE* ip, const BYTE* const iLimit, \
1330 size_t* offBasePtr) \
1331 { \
1332 assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \
1333 return ZSTD_BtFindBestMatch(ms, ip, iLimit, offBasePtr, mls, ZSTD_##dictMode); \
1334 } \
1335
1336#define GEN_ZSTD_HC_SEARCH_FN(dictMode, mls) \
1337 ZSTD_SEARCH_FN_ATTRS size_t ZSTD_HC_SEARCH_FN(dictMode, mls)( \
1338 ZSTD_matchState_t* ms, \
1339 const BYTE* ip, const BYTE* const iLimit, \
1340 size_t* offsetPtr) \
1341 { \
1342 assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \
1343 return ZSTD_HcFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode); \
1344 } \
1345
1346#define GEN_ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog) \
1347 ZSTD_SEARCH_FN_ATTRS size_t ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog)( \
1348 ZSTD_matchState_t* ms, \
1349 const BYTE* ip, const BYTE* const iLimit, \
1350 size_t* offsetPtr) \
1351 { \
1352 assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \
1353 assert(MAX(4, MIN(6, ms->cParams.searchLog)) == rowLog); \
1354 return ZSTD_RowFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode, rowLog); \
1355 } \
1356
1357#define ZSTD_FOR_EACH_ROWLOG(X, dictMode, mls) \
1358 X(dictMode, mls, 4) \
1359 X(dictMode, mls, 5) \
1360 X(dictMode, mls, 6)
1361
1362#define ZSTD_FOR_EACH_MLS_ROWLOG(X, dictMode) \
1363 ZSTD_FOR_EACH_ROWLOG(X, dictMode, 4) \
1364 ZSTD_FOR_EACH_ROWLOG(X, dictMode, 5) \
1365 ZSTD_FOR_EACH_ROWLOG(X, dictMode, 6)
1366
1367#define ZSTD_FOR_EACH_MLS(X, dictMode) \
1368 X(dictMode, 4) \
1369 X(dictMode, 5) \
1370 X(dictMode, 6)
1371
1372#define ZSTD_FOR_EACH_DICT_MODE(X, ...) \
1373 X(__VA_ARGS__, noDict) \
1374 X(__VA_ARGS__, extDict) \
1375 X(__VA_ARGS__, dictMatchState) \
1376 X(__VA_ARGS__, dedicatedDictSearch)
1377
1378/* Generate row search fns for each combination of (dictMode, mls, rowLog) */
1379ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS_ROWLOG, GEN_ZSTD_ROW_SEARCH_FN)
1380/* Generate binary Tree search fns for each combination of (dictMode, mls) */
1381ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_BT_SEARCH_FN)
1382/* Generate hash chain search fns for each combination of (dictMode, mls) */
1383ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_HC_SEARCH_FN)
1384
1385typedef enum { search_hashChain=0, search_binaryTree=1, search_rowHash=2 } searchMethod_e;
1386
1387#define GEN_ZSTD_CALL_BT_SEARCH_FN(dictMode, mls) \
1388 case mls: \
1389 return ZSTD_BT_SEARCH_FN(dictMode, mls)(ms, ip, iend, offsetPtr);
1390#define GEN_ZSTD_CALL_HC_SEARCH_FN(dictMode, mls) \
1391 case mls: \
1392 return ZSTD_HC_SEARCH_FN(dictMode, mls)(ms, ip, iend, offsetPtr);
1393#define GEN_ZSTD_CALL_ROW_SEARCH_FN(dictMode, mls, rowLog) \
1394 case rowLog: \
1395 return ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog)(ms, ip, iend, offsetPtr);
1396
1397#define ZSTD_SWITCH_MLS(X, dictMode) \
1398 switch (mls) { \
1399 ZSTD_FOR_EACH_MLS(X, dictMode) \
1400 }
1401
1402#define ZSTD_SWITCH_ROWLOG(dictMode, mls) \
1403 case mls: \
1404 switch (rowLog) { \
1405 ZSTD_FOR_EACH_ROWLOG(GEN_ZSTD_CALL_ROW_SEARCH_FN, dictMode, mls) \
1406 } \
1407 ZSTD_UNREACHABLE; \
1408 break;
1409
1410#define ZSTD_SWITCH_SEARCH_METHOD(dictMode) \
1411 switch (searchMethod) { \
1412 case search_hashChain: \
1413 ZSTD_SWITCH_MLS(GEN_ZSTD_CALL_HC_SEARCH_FN, dictMode) \
1414 break; \
1415 case search_binaryTree: \
1416 ZSTD_SWITCH_MLS(GEN_ZSTD_CALL_BT_SEARCH_FN, dictMode) \
1417 break; \
1418 case search_rowHash: \
1419 ZSTD_SWITCH_MLS(ZSTD_SWITCH_ROWLOG, dictMode) \
1420 break; \
1421 } \
1422 ZSTD_UNREACHABLE;
1423
1424/*
1425 * Searches for the longest match at @p ip.
1426 * Dispatches to the correct implementation function based on the
1427 * (searchMethod, dictMode, mls, rowLog). We use switch statements
1428 * here instead of using an indirect function call through a function
1429 * pointer because after Spectre and Meltdown mitigations, indirect
1430 * function calls can be very costly, especially in the kernel.
1431 *
1432 * NOTE: dictMode and searchMethod should be templated, so those switch
1433 * statements should be optimized out. Only the mls & rowLog switches
1434 * should be left.
1435 *
1436 * @param ms The match state.
1437 * @param ip The position to search at.
1438 * @param iend The end of the input data.
1439 * @param[out] offsetPtr Stores the match offset into this pointer.
1440 * @param mls The minimum search length, in the range [4, 6].
1441 * @param rowLog The row log (if applicable), in the range [4, 6].
1442 * @param searchMethod The search method to use (templated).
1443 * @param dictMode The dictMode (templated).
1444 *
1445 * @returns The length of the longest match found, or < mls if no match is found.
1446 * If a match is found its offset is stored in @p offsetPtr.
1447 */
1448FORCE_INLINE_TEMPLATE size_t ZSTD_searchMax(
1449 ZSTD_matchState_t* ms,
1450 const BYTE* ip,
1451 const BYTE* iend,
1452 size_t* offsetPtr,
1453 U32 const mls,
1454 U32 const rowLog,
1455 searchMethod_e const searchMethod,
1456 ZSTD_dictMode_e const dictMode)
1457{
1458 if (dictMode == ZSTD_noDict) {
1459 ZSTD_SWITCH_SEARCH_METHOD(noDict)
1460 } else if (dictMode == ZSTD_extDict) {
1461 ZSTD_SWITCH_SEARCH_METHOD(extDict)
1462 } else if (dictMode == ZSTD_dictMatchState) {
1463 ZSTD_SWITCH_SEARCH_METHOD(dictMatchState)
1464 } else if (dictMode == ZSTD_dedicatedDictSearch) {
1465 ZSTD_SWITCH_SEARCH_METHOD(dedicatedDictSearch)
1466 }
1467 ZSTD_UNREACHABLE;
1468 return 0;
1469}
1470
1471/* *******************************
1472* Common parser - lazy strategy
1473*********************************/
1474
1475FORCE_INLINE_TEMPLATE size_t
1476ZSTD_compressBlock_lazy_generic(
1477 ZSTD_matchState_t* ms, seqStore_t* seqStore,
1478 U32 rep[ZSTD_REP_NUM],
1479 const void* src, size_t srcSize,
1480 const searchMethod_e searchMethod, const U32 depth,
1481 ZSTD_dictMode_e const dictMode)
1482{
1483 const BYTE* const istart = (const BYTE*)src;
1484 const BYTE* ip = istart;
1485 const BYTE* anchor = istart;
1486 const BYTE* const iend = istart + srcSize;
1487 const BYTE* const ilimit = (searchMethod == search_rowHash) ? iend - 8 - ZSTD_ROW_HASH_CACHE_SIZE : iend - 8;
1488 const BYTE* const base = ms->window.base;
1489 const U32 prefixLowestIndex = ms->window.dictLimit;
1490 const BYTE* const prefixLowest = base + prefixLowestIndex;
1491 const U32 mls = BOUNDED(4, ms->cParams.minMatch, 6);
1492 const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
1493
1494 U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0;
1495
1496 const int isDMS = dictMode == ZSTD_dictMatchState;
1497 const int isDDS = dictMode == ZSTD_dedicatedDictSearch;
1498 const int isDxS = isDMS || isDDS;
1499 const ZSTD_matchState_t* const dms = ms->dictMatchState;
1500 const U32 dictLowestIndex = isDxS ? dms->window.dictLimit : 0;
1501 const BYTE* const dictBase = isDxS ? dms->window.base : NULL;
1502 const BYTE* const dictLowest = isDxS ? dictBase + dictLowestIndex : NULL;
1503 const BYTE* const dictEnd = isDxS ? dms->window.nextSrc : NULL;
1504 const U32 dictIndexDelta = isDxS ?
1505 prefixLowestIndex - (U32)(dictEnd - dictBase) :
1506 0;
1507 const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
1508
1509 DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u) (searchFunc=%u)", (U32)dictMode, (U32)searchMethod);
1510 ip += (dictAndPrefixLength == 0);
1511 if (dictMode == ZSTD_noDict) {
1512 U32 const curr = (U32)(ip - base);
1513 U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, ms->cParams.windowLog);
1514 U32 const maxRep = curr - windowLow;
1515 if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
1516 if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
1517 }
1518 if (isDxS) {
1519 /* dictMatchState repCode checks don't currently handle repCode == 0
1520 * disabling. */
1521 assert(offset_1 <= dictAndPrefixLength);
1522 assert(offset_2 <= dictAndPrefixLength);
1523 }
1524
1525 if (searchMethod == search_rowHash) {
1526 ZSTD_row_fillHashCache(ms, base, rowLog,
1527 MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */),
1528 ms->nextToUpdate, ilimit);
1529 }
1530
1531 /* Match Loop */
1532#if defined(__x86_64__)
1533 /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
1534 * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
1535 */
1536 __asm__(".p2align 5");
1537#endif
1538 while (ip < ilimit) {
1539 size_t matchLength=0;
1540 size_t offcode=STORE_REPCODE_1;
1541 const BYTE* start=ip+1;
1542 DEBUGLOG(7, "search baseline (depth 0)");
1543
1544 /* check repCode */
1545 if (isDxS) {
1546 const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
1547 const BYTE* repMatch = ((dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch)
1548 && repIndex < prefixLowestIndex) ?
1549 dictBase + (repIndex - dictIndexDelta) :
1550 base + repIndex;
1551 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
1552 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
1553 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
1554 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
1555 if (depth==0) goto _storeSequence;
1556 }
1557 }
1558 if ( dictMode == ZSTD_noDict
1559 && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
1560 matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
1561 if (depth==0) goto _storeSequence;
1562 }
1563
1564 /* first search (depth 0) */
1565 { size_t offsetFound = 999999999;
1566 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offsetFound, mls, rowLog, searchMethod, dictMode);
1567 if (ml2 > matchLength)
1568 matchLength = ml2, start = ip, offcode=offsetFound;
1569 }
1570
1571 if (matchLength < 4) {
1572 ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */
1573 continue;
1574 }
1575
1576 /* let's try to find a better solution */
1577 if (depth>=1)
1578 while (ip<ilimit) {
1579 DEBUGLOG(7, "search depth 1");
1580 ip ++;
1581 if ( (dictMode == ZSTD_noDict)
1582 && (offcode) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
1583 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
1584 int const gain2 = (int)(mlRep * 3);
1585 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 1);
1586 if ((mlRep >= 4) && (gain2 > gain1))
1587 matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
1588 }
1589 if (isDxS) {
1590 const U32 repIndex = (U32)(ip - base) - offset_1;
1591 const BYTE* repMatch = repIndex < prefixLowestIndex ?
1592 dictBase + (repIndex - dictIndexDelta) :
1593 base + repIndex;
1594 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
1595 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
1596 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
1597 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
1598 int const gain2 = (int)(mlRep * 3);
1599 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 1);
1600 if ((mlRep >= 4) && (gain2 > gain1))
1601 matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
1602 }
1603 }
1604 { size_t offset2=999999999;
1605 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offset2, mls, rowLog, searchMethod, dictMode);
1606 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offset2))); /* raw approx */
1607 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 4);
1608 if ((ml2 >= 4) && (gain2 > gain1)) {
1609 matchLength = ml2, offcode = offset2, start = ip;
1610 continue; /* search a better one */
1611 } }
1612
1613 /* let's find an even better one */
1614 if ((depth==2) && (ip<ilimit)) {
1615 DEBUGLOG(7, "search depth 2");
1616 ip ++;
1617 if ( (dictMode == ZSTD_noDict)
1618 && (offcode) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
1619 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
1620 int const gain2 = (int)(mlRep * 4);
1621 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 1);
1622 if ((mlRep >= 4) && (gain2 > gain1))
1623 matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
1624 }
1625 if (isDxS) {
1626 const U32 repIndex = (U32)(ip - base) - offset_1;
1627 const BYTE* repMatch = repIndex < prefixLowestIndex ?
1628 dictBase + (repIndex - dictIndexDelta) :
1629 base + repIndex;
1630 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
1631 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
1632 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
1633 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
1634 int const gain2 = (int)(mlRep * 4);
1635 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 1);
1636 if ((mlRep >= 4) && (gain2 > gain1))
1637 matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
1638 }
1639 }
1640 { size_t offset2=999999999;
1641 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offset2, mls, rowLog, searchMethod, dictMode);
1642 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offset2))); /* raw approx */
1643 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 7);
1644 if ((ml2 >= 4) && (gain2 > gain1)) {
1645 matchLength = ml2, offcode = offset2, start = ip;
1646 continue;
1647 } } }
1648 break; /* nothing found : store previous solution */
1649 }
1650
1651 /* NOTE:
1652 * Pay attention that `start[-value]` can lead to strange undefined behavior
1653 * notably if `value` is unsigned, resulting in a large positive `-value`.
1654 */
1655 /* catch up */
1656 if (STORED_IS_OFFSET(offcode)) {
1657 if (dictMode == ZSTD_noDict) {
1658 while ( ((start > anchor) & (start - STORED_OFFSET(offcode) > prefixLowest))
1659 && (start[-1] == (start-STORED_OFFSET(offcode))[-1]) ) /* only search for offset within prefix */
1660 { start--; matchLength++; }
1661 }
1662 if (isDxS) {
1663 U32 const matchIndex = (U32)((size_t)(start-base) - STORED_OFFSET(offcode));
1664 const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex;
1665 const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest;
1666 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
1667 }
1668 offset_2 = offset_1; offset_1 = (U32)STORED_OFFSET(offcode);
1669 }
1670 /* store sequence */
1671_storeSequence:
1672 { size_t const litLength = (size_t)(start - anchor);
1673 ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offcode, matchLength);
1674 anchor = ip = start + matchLength;
1675 }
1676
1677 /* check immediate repcode */
1678 if (isDxS) {
1679 while (ip <= ilimit) {
1680 U32 const current2 = (U32)(ip-base);
1681 U32 const repIndex = current2 - offset_2;
1682 const BYTE* repMatch = repIndex < prefixLowestIndex ?
1683 dictBase - dictIndexDelta + repIndex :
1684 base + repIndex;
1685 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */)
1686 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
1687 const BYTE* const repEnd2 = repIndex < prefixLowestIndex ? dictEnd : iend;
1688 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd2, prefixLowest) + 4;
1689 offcode = offset_2; offset_2 = offset_1; offset_1 = (U32)offcode; /* swap offset_2 <=> offset_1 */
1690 ZSTD_storeSeq(seqStore, 0, anchor, iend, STORE_REPCODE_1, matchLength);
1691 ip += matchLength;
1692 anchor = ip;
1693 continue;
1694 }
1695 break;
1696 }
1697 }
1698
1699 if (dictMode == ZSTD_noDict) {
1700 while ( ((ip <= ilimit) & (offset_2>0))
1701 && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
1702 /* store sequence */
1703 matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
1704 offcode = offset_2; offset_2 = offset_1; offset_1 = (U32)offcode; /* swap repcodes */
1705 ZSTD_storeSeq(seqStore, 0, anchor, iend, STORE_REPCODE_1, matchLength);
1706 ip += matchLength;
1707 anchor = ip;
1708 continue; /* faster when present ... (?) */
1709 } } }
1710
1711 /* Save reps for next block */
1712 rep[0] = offset_1 ? offset_1 : savedOffset;
1713 rep[1] = offset_2 ? offset_2 : savedOffset;
1714
1715 /* Return the last literals size */
1716 return (size_t)(iend - anchor);
1717}
1718
1719
1720size_t ZSTD_compressBlock_btlazy2(
1721 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1722 void const* src, size_t srcSize)
1723{
1724 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_noDict);
1725}
1726
1727size_t ZSTD_compressBlock_lazy2(
1728 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1729 void const* src, size_t srcSize)
1730{
1731 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_noDict);
1732}
1733
1734size_t ZSTD_compressBlock_lazy(
1735 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1736 void const* src, size_t srcSize)
1737{
1738 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_noDict);
1739}
1740
1741size_t ZSTD_compressBlock_greedy(
1742 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1743 void const* src, size_t srcSize)
1744{
1745 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_noDict);
1746}
1747
1748size_t ZSTD_compressBlock_btlazy2_dictMatchState(
1749 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1750 void const* src, size_t srcSize)
1751{
1752 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_dictMatchState);
1753}
1754
1755size_t ZSTD_compressBlock_lazy2_dictMatchState(
1756 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1757 void const* src, size_t srcSize)
1758{
1759 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dictMatchState);
1760}
1761
1762size_t ZSTD_compressBlock_lazy_dictMatchState(
1763 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1764 void const* src, size_t srcSize)
1765{
1766 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dictMatchState);
1767}
1768
1769size_t ZSTD_compressBlock_greedy_dictMatchState(
1770 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1771 void const* src, size_t srcSize)
1772{
1773 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dictMatchState);
1774}
1775
1776
1777size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch(
1778 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1779 void const* src, size_t srcSize)
1780{
1781 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dedicatedDictSearch);
1782}
1783
1784size_t ZSTD_compressBlock_lazy_dedicatedDictSearch(
1785 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1786 void const* src, size_t srcSize)
1787{
1788 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dedicatedDictSearch);
1789}
1790
1791size_t ZSTD_compressBlock_greedy_dedicatedDictSearch(
1792 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1793 void const* src, size_t srcSize)
1794{
1795 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dedicatedDictSearch);
1796}
1797
1798/* Row-based matchfinder */
1799size_t ZSTD_compressBlock_lazy2_row(
1800 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1801 void const* src, size_t srcSize)
1802{
1803 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2, ZSTD_noDict);
1804}
1805
1806size_t ZSTD_compressBlock_lazy_row(
1807 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1808 void const* src, size_t srcSize)
1809{
1810 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1, ZSTD_noDict);
1811}
1812
1813size_t ZSTD_compressBlock_greedy_row(
1814 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1815 void const* src, size_t srcSize)
1816{
1817 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0, ZSTD_noDict);
1818}
1819
1820size_t ZSTD_compressBlock_lazy2_dictMatchState_row(
1821 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1822 void const* src, size_t srcSize)
1823{
1824 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2, ZSTD_dictMatchState);
1825}
1826
1827size_t ZSTD_compressBlock_lazy_dictMatchState_row(
1828 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1829 void const* src, size_t srcSize)
1830{
1831 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1, ZSTD_dictMatchState);
1832}
1833
1834size_t ZSTD_compressBlock_greedy_dictMatchState_row(
1835 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1836 void const* src, size_t srcSize)
1837{
1838 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0, ZSTD_dictMatchState);
1839}
1840
1841
1842size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch_row(
1843 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1844 void const* src, size_t srcSize)
1845{
1846 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2, ZSTD_dedicatedDictSearch);
1847}
1848
1849size_t ZSTD_compressBlock_lazy_dedicatedDictSearch_row(
1850 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1851 void const* src, size_t srcSize)
1852{
1853 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1, ZSTD_dedicatedDictSearch);
1854}
1855
1856size_t ZSTD_compressBlock_greedy_dedicatedDictSearch_row(
1857 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1858 void const* src, size_t srcSize)
1859{
1860 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0, ZSTD_dedicatedDictSearch);
1861}
1862
1863FORCE_INLINE_TEMPLATE
1864size_t ZSTD_compressBlock_lazy_extDict_generic(
1865 ZSTD_matchState_t* ms, seqStore_t* seqStore,
1866 U32 rep[ZSTD_REP_NUM],
1867 const void* src, size_t srcSize,
1868 const searchMethod_e searchMethod, const U32 depth)
1869{
1870 const BYTE* const istart = (const BYTE*)src;
1871 const BYTE* ip = istart;
1872 const BYTE* anchor = istart;
1873 const BYTE* const iend = istart + srcSize;
1874 const BYTE* const ilimit = searchMethod == search_rowHash ? iend - 8 - ZSTD_ROW_HASH_CACHE_SIZE : iend - 8;
1875 const BYTE* const base = ms->window.base;
1876 const U32 dictLimit = ms->window.dictLimit;
1877 const BYTE* const prefixStart = base + dictLimit;
1878 const BYTE* const dictBase = ms->window.dictBase;
1879 const BYTE* const dictEnd = dictBase + dictLimit;
1880 const BYTE* const dictStart = dictBase + ms->window.lowLimit;
1881 const U32 windowLog = ms->cParams.windowLog;
1882 const U32 mls = BOUNDED(4, ms->cParams.minMatch, 6);
1883 const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
1884
1885 U32 offset_1 = rep[0], offset_2 = rep[1];
1886
1887 DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic (searchFunc=%u)", (U32)searchMethod);
1888
1889 /* init */
1890 ip += (ip == prefixStart);
1891 if (searchMethod == search_rowHash) {
1892 ZSTD_row_fillHashCache(ms, base, rowLog,
1893 MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */),
1894 ms->nextToUpdate, ilimit);
1895 }
1896
1897 /* Match Loop */
1898#if defined(__x86_64__)
1899 /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
1900 * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
1901 */
1902 __asm__(".p2align 5");
1903#endif
1904 while (ip < ilimit) {
1905 size_t matchLength=0;
1906 size_t offcode=STORE_REPCODE_1;
1907 const BYTE* start=ip+1;
1908 U32 curr = (U32)(ip-base);
1909
1910 /* check repCode */
1911 { const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr+1, windowLog);
1912 const U32 repIndex = (U32)(curr+1 - offset_1);
1913 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
1914 const BYTE* const repMatch = repBase + repIndex;
1915 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
1916 & (offset_1 <= curr+1 - windowLow) ) /* note: we are searching at curr+1 */
1917 if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
1918 /* repcode detected we should take it */
1919 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
1920 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4;
1921 if (depth==0) goto _storeSequence;
1922 } }
1923
1924 /* first search (depth 0) */
1925 { size_t offsetFound = 999999999;
1926 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offsetFound, mls, rowLog, searchMethod, ZSTD_extDict);
1927 if (ml2 > matchLength)
1928 matchLength = ml2, start = ip, offcode=offsetFound;
1929 }
1930
1931 if (matchLength < 4) {
1932 ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */
1933 continue;
1934 }
1935
1936 /* let's try to find a better solution */
1937 if (depth>=1)
1938 while (ip<ilimit) {
1939 ip ++;
1940 curr++;
1941 /* check repCode */
1942 if (offcode) {
1943 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog);
1944 const U32 repIndex = (U32)(curr - offset_1);
1945 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
1946 const BYTE* const repMatch = repBase + repIndex;
1947 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
1948 & (offset_1 <= curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
1949 if (MEM_read32(ip) == MEM_read32(repMatch)) {
1950 /* repcode detected */
1951 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
1952 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
1953 int const gain2 = (int)(repLength * 3);
1954 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 1);
1955 if ((repLength >= 4) && (gain2 > gain1))
1956 matchLength = repLength, offcode = STORE_REPCODE_1, start = ip;
1957 } }
1958
1959 /* search match, depth 1 */
1960 { size_t offset2=999999999;
1961 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offset2, mls, rowLog, searchMethod, ZSTD_extDict);
1962 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offset2))); /* raw approx */
1963 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 4);
1964 if ((ml2 >= 4) && (gain2 > gain1)) {
1965 matchLength = ml2, offcode = offset2, start = ip;
1966 continue; /* search a better one */
1967 } }
1968
1969 /* let's find an even better one */
1970 if ((depth==2) && (ip<ilimit)) {
1971 ip ++;
1972 curr++;
1973 /* check repCode */
1974 if (offcode) {
1975 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog);
1976 const U32 repIndex = (U32)(curr - offset_1);
1977 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
1978 const BYTE* const repMatch = repBase + repIndex;
1979 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
1980 & (offset_1 <= curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
1981 if (MEM_read32(ip) == MEM_read32(repMatch)) {
1982 /* repcode detected */
1983 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
1984 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
1985 int const gain2 = (int)(repLength * 4);
1986 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 1);
1987 if ((repLength >= 4) && (gain2 > gain1))
1988 matchLength = repLength, offcode = STORE_REPCODE_1, start = ip;
1989 } }
1990
1991 /* search match, depth 2 */
1992 { size_t offset2=999999999;
1993 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offset2, mls, rowLog, searchMethod, ZSTD_extDict);
1994 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offset2))); /* raw approx */
1995 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 7);
1996 if ((ml2 >= 4) && (gain2 > gain1)) {
1997 matchLength = ml2, offcode = offset2, start = ip;
1998 continue;
1999 } } }
2000 break; /* nothing found : store previous solution */
2001 }
2002
2003 /* catch up */
2004 if (STORED_IS_OFFSET(offcode)) {
2005 U32 const matchIndex = (U32)((size_t)(start-base) - STORED_OFFSET(offcode));
2006 const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
2007 const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
2008 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
2009 offset_2 = offset_1; offset_1 = (U32)STORED_OFFSET(offcode);
2010 }
2011
2012 /* store sequence */
2013_storeSequence:
2014 { size_t const litLength = (size_t)(start - anchor);
2015 ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offcode, matchLength);
2016 anchor = ip = start + matchLength;
2017 }
2018
2019 /* check immediate repcode */
2020 while (ip <= ilimit) {
2021 const U32 repCurrent = (U32)(ip-base);
2022 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, repCurrent, windowLog);
2023 const U32 repIndex = repCurrent - offset_2;
2024 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
2025 const BYTE* const repMatch = repBase + repIndex;
2026 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
2027 & (offset_2 <= repCurrent - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
2028 if (MEM_read32(ip) == MEM_read32(repMatch)) {
2029 /* repcode detected we should take it */
2030 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
2031 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
2032 offcode = offset_2; offset_2 = offset_1; offset_1 = (U32)offcode; /* swap offset history */
2033 ZSTD_storeSeq(seqStore, 0, anchor, iend, STORE_REPCODE_1, matchLength);
2034 ip += matchLength;
2035 anchor = ip;
2036 continue; /* faster when present ... (?) */
2037 }
2038 break;
2039 } }
2040
2041 /* Save reps for next block */
2042 rep[0] = offset_1;
2043 rep[1] = offset_2;
2044
2045 /* Return the last literals size */
2046 return (size_t)(iend - anchor);
2047}
2048
2049
2050size_t ZSTD_compressBlock_greedy_extDict(
2051 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2052 void const* src, size_t srcSize)
2053{
2054 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0);
2055}
2056
2057size_t ZSTD_compressBlock_lazy_extDict(
2058 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2059 void const* src, size_t srcSize)
2060
2061{
2062 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1);
2063}
2064
2065size_t ZSTD_compressBlock_lazy2_extDict(
2066 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2067 void const* src, size_t srcSize)
2068
2069{
2070 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2);
2071}
2072
2073size_t ZSTD_compressBlock_btlazy2_extDict(
2074 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2075 void const* src, size_t srcSize)
2076
2077{
2078 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2);
2079}
2080
2081size_t ZSTD_compressBlock_greedy_extDict_row(
2082 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2083 void const* src, size_t srcSize)
2084{
2085 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0);
2086}
2087
2088size_t ZSTD_compressBlock_lazy_extDict_row(
2089 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2090 void const* src, size_t srcSize)
2091
2092{
2093 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1);
2094}
2095
2096size_t ZSTD_compressBlock_lazy2_extDict_row(
2097 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2098 void const* src, size_t srcSize)
2099
2100{
2101 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2);
2102}