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[pcsx_rearmed.git] / deps / libchdr / deps / zstd-1.5.6 / lib / compress / zstd_lazy.c
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648db22b 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_lazy.h"
13#include "../common/bits.h" /* ZSTD_countTrailingZeros64 */
14
f535537f 15#if !defined(ZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR) \
16 || !defined(ZSTD_EXCLUDE_LAZY_BLOCK_COMPRESSOR) \
17 || !defined(ZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR) \
18 || !defined(ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR)
19
648db22b 20#define kLazySkippingStep 8
21
22
23/*-*************************************
24* Binary Tree search
25***************************************/
26
f535537f 27static
28ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
29void ZSTD_updateDUBT(ZSTD_matchState_t* ms,
648db22b 30 const BYTE* ip, const BYTE* iend,
31 U32 mls)
32{
33 const ZSTD_compressionParameters* const cParams = &ms->cParams;
34 U32* const hashTable = ms->hashTable;
35 U32 const hashLog = cParams->hashLog;
36
37 U32* const bt = ms->chainTable;
38 U32 const btLog = cParams->chainLog - 1;
39 U32 const btMask = (1 << btLog) - 1;
40
41 const BYTE* const base = ms->window.base;
42 U32 const target = (U32)(ip - base);
43 U32 idx = ms->nextToUpdate;
44
45 if (idx != target)
46 DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)",
47 idx, target, ms->window.dictLimit);
48 assert(ip + 8 <= iend); /* condition for ZSTD_hashPtr */
49 (void)iend;
50
51 assert(idx >= ms->window.dictLimit); /* condition for valid base+idx */
52 for ( ; idx < target ; idx++) {
53 size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls); /* assumption : ip + 8 <= iend */
54 U32 const matchIndex = hashTable[h];
55
56 U32* const nextCandidatePtr = bt + 2*(idx&btMask);
57 U32* const sortMarkPtr = nextCandidatePtr + 1;
58
59 DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx);
60 hashTable[h] = idx; /* Update Hash Table */
61 *nextCandidatePtr = matchIndex; /* update BT like a chain */
62 *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK;
63 }
64 ms->nextToUpdate = target;
65}
66
67
68/** ZSTD_insertDUBT1() :
69 * sort one already inserted but unsorted position
70 * assumption : curr >= btlow == (curr - btmask)
71 * doesn't fail */
f535537f 72static
73ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
74void ZSTD_insertDUBT1(const ZSTD_matchState_t* ms,
648db22b 75 U32 curr, const BYTE* inputEnd,
76 U32 nbCompares, U32 btLow,
77 const ZSTD_dictMode_e dictMode)
78{
79 const ZSTD_compressionParameters* const cParams = &ms->cParams;
80 U32* const bt = ms->chainTable;
81 U32 const btLog = cParams->chainLog - 1;
82 U32 const btMask = (1 << btLog) - 1;
83 size_t commonLengthSmaller=0, commonLengthLarger=0;
84 const BYTE* const base = ms->window.base;
85 const BYTE* const dictBase = ms->window.dictBase;
86 const U32 dictLimit = ms->window.dictLimit;
87 const BYTE* const ip = (curr>=dictLimit) ? base + curr : dictBase + curr;
88 const BYTE* const iend = (curr>=dictLimit) ? inputEnd : dictBase + dictLimit;
89 const BYTE* const dictEnd = dictBase + dictLimit;
90 const BYTE* const prefixStart = base + dictLimit;
91 const BYTE* match;
92 U32* smallerPtr = bt + 2*(curr&btMask);
93 U32* largerPtr = smallerPtr + 1;
94 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) */
95 U32 dummy32; /* to be nullified at the end */
96 U32 const windowValid = ms->window.lowLimit;
97 U32 const maxDistance = 1U << cParams->windowLog;
98 U32 const windowLow = (curr - windowValid > maxDistance) ? curr - maxDistance : windowValid;
99
100
101 DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
102 curr, dictLimit, windowLow);
103 assert(curr >= btLow);
104 assert(ip < iend); /* condition for ZSTD_count */
105
106 for (; nbCompares && (matchIndex > windowLow); --nbCompares) {
107 U32* const nextPtr = bt + 2*(matchIndex & btMask);
108 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
109 assert(matchIndex < curr);
110 /* note : all candidates are now supposed sorted,
111 * but it's still possible to have nextPtr[1] == ZSTD_DUBT_UNSORTED_MARK
112 * when a real index has the same value as ZSTD_DUBT_UNSORTED_MARK */
113
114 if ( (dictMode != ZSTD_extDict)
115 || (matchIndex+matchLength >= dictLimit) /* both in current segment*/
116 || (curr < dictLimit) /* both in extDict */) {
117 const BYTE* const mBase = ( (dictMode != ZSTD_extDict)
118 || (matchIndex+matchLength >= dictLimit)) ?
119 base : dictBase;
120 assert( (matchIndex+matchLength >= dictLimit) /* might be wrong if extDict is incorrectly set to 0 */
121 || (curr < dictLimit) );
122 match = mBase + matchIndex;
123 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
124 } else {
125 match = dictBase + matchIndex;
126 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
127 if (matchIndex+matchLength >= dictLimit)
128 match = base + matchIndex; /* preparation for next read of match[matchLength] */
129 }
130
131 DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ",
132 curr, matchIndex, (U32)matchLength);
133
134 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
135 break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
136 }
137
138 if (match[matchLength] < ip[matchLength]) { /* necessarily within buffer */
139 /* match is smaller than current */
140 *smallerPtr = matchIndex; /* update smaller idx */
141 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
142 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop searching */
143 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u",
144 matchIndex, btLow, nextPtr[1]);
145 smallerPtr = nextPtr+1; /* new "candidate" => larger than match, which was smaller than target */
146 matchIndex = nextPtr[1]; /* new matchIndex, larger than previous and closer to current */
147 } else {
148 /* match is larger than current */
149 *largerPtr = matchIndex;
150 commonLengthLarger = matchLength;
151 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop searching */
152 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u",
153 matchIndex, btLow, nextPtr[0]);
154 largerPtr = nextPtr;
155 matchIndex = nextPtr[0];
156 } }
157
158 *smallerPtr = *largerPtr = 0;
159}
160
161
f535537f 162static
163ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
164size_t ZSTD_DUBT_findBetterDictMatch (
648db22b 165 const ZSTD_matchState_t* ms,
166 const BYTE* const ip, const BYTE* const iend,
167 size_t* offsetPtr,
168 size_t bestLength,
169 U32 nbCompares,
170 U32 const mls,
171 const ZSTD_dictMode_e dictMode)
172{
173 const ZSTD_matchState_t * const dms = ms->dictMatchState;
174 const ZSTD_compressionParameters* const dmsCParams = &dms->cParams;
175 const U32 * const dictHashTable = dms->hashTable;
176 U32 const hashLog = dmsCParams->hashLog;
177 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
178 U32 dictMatchIndex = dictHashTable[h];
179
180 const BYTE* const base = ms->window.base;
181 const BYTE* const prefixStart = base + ms->window.dictLimit;
182 U32 const curr = (U32)(ip-base);
183 const BYTE* const dictBase = dms->window.base;
184 const BYTE* const dictEnd = dms->window.nextSrc;
185 U32 const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base);
186 U32 const dictLowLimit = dms->window.lowLimit;
187 U32 const dictIndexDelta = ms->window.lowLimit - dictHighLimit;
188
189 U32* const dictBt = dms->chainTable;
190 U32 const btLog = dmsCParams->chainLog - 1;
191 U32 const btMask = (1 << btLog) - 1;
192 U32 const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask;
193
194 size_t commonLengthSmaller=0, commonLengthLarger=0;
195
196 (void)dictMode;
197 assert(dictMode == ZSTD_dictMatchState);
198
199 for (; nbCompares && (dictMatchIndex > dictLowLimit); --nbCompares) {
200 U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask);
201 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
202 const BYTE* match = dictBase + dictMatchIndex;
203 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
204 if (dictMatchIndex+matchLength >= dictHighLimit)
205 match = base + dictMatchIndex + dictIndexDelta; /* to prepare for next usage of match[matchLength] */
206
207 if (matchLength > bestLength) {
208 U32 matchIndex = dictMatchIndex + dictIndexDelta;
209 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(curr-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) {
210 DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)",
211 curr, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, OFFSET_TO_OFFBASE(curr - matchIndex), dictMatchIndex, matchIndex);
212 bestLength = matchLength, *offsetPtr = OFFSET_TO_OFFBASE(curr - matchIndex);
213 }
214 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 */
215 break; /* drop, to guarantee consistency (miss a little bit of compression) */
216 }
217 }
218
219 if (match[matchLength] < ip[matchLength]) {
220 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */
221 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
222 dictMatchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
223 } else {
224 /* match is larger than current */
225 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */
226 commonLengthLarger = matchLength;
227 dictMatchIndex = nextPtr[0];
228 }
229 }
230
231 if (bestLength >= MINMATCH) {
232 U32 const mIndex = curr - (U32)OFFBASE_TO_OFFSET(*offsetPtr); (void)mIndex;
233 DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
234 curr, (U32)bestLength, (U32)*offsetPtr, mIndex);
235 }
236 return bestLength;
237
238}
239
240
f535537f 241static
242ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
243size_t ZSTD_DUBT_findBestMatch(ZSTD_matchState_t* ms,
648db22b 244 const BYTE* const ip, const BYTE* const iend,
245 size_t* offBasePtr,
246 U32 const mls,
247 const ZSTD_dictMode_e dictMode)
248{
249 const ZSTD_compressionParameters* const cParams = &ms->cParams;
250 U32* const hashTable = ms->hashTable;
251 U32 const hashLog = cParams->hashLog;
252 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
253 U32 matchIndex = hashTable[h];
254
255 const BYTE* const base = ms->window.base;
256 U32 const curr = (U32)(ip-base);
257 U32 const windowLow = ZSTD_getLowestMatchIndex(ms, curr, cParams->windowLog);
258
259 U32* const bt = ms->chainTable;
260 U32 const btLog = cParams->chainLog - 1;
261 U32 const btMask = (1 << btLog) - 1;
262 U32 const btLow = (btMask >= curr) ? 0 : curr - btMask;
263 U32 const unsortLimit = MAX(btLow, windowLow);
264
265 U32* nextCandidate = bt + 2*(matchIndex&btMask);
266 U32* unsortedMark = bt + 2*(matchIndex&btMask) + 1;
267 U32 nbCompares = 1U << cParams->searchLog;
268 U32 nbCandidates = nbCompares;
269 U32 previousCandidate = 0;
270
271 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", curr);
272 assert(ip <= iend-8); /* required for h calculation */
273 assert(dictMode != ZSTD_dedicatedDictSearch);
274
275 /* reach end of unsorted candidates list */
276 while ( (matchIndex > unsortLimit)
277 && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK)
278 && (nbCandidates > 1) ) {
279 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted",
280 matchIndex);
281 *unsortedMark = previousCandidate; /* the unsortedMark becomes a reversed chain, to move up back to original position */
282 previousCandidate = matchIndex;
283 matchIndex = *nextCandidate;
284 nextCandidate = bt + 2*(matchIndex&btMask);
285 unsortedMark = bt + 2*(matchIndex&btMask) + 1;
286 nbCandidates --;
287 }
288
289 /* nullify last candidate if it's still unsorted
290 * simplification, detrimental to compression ratio, beneficial for speed */
291 if ( (matchIndex > unsortLimit)
292 && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) {
293 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u",
294 matchIndex);
295 *nextCandidate = *unsortedMark = 0;
296 }
297
298 /* batch sort stacked candidates */
299 matchIndex = previousCandidate;
300 while (matchIndex) { /* will end on matchIndex == 0 */
301 U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1;
302 U32 const nextCandidateIdx = *nextCandidateIdxPtr;
303 ZSTD_insertDUBT1(ms, matchIndex, iend,
304 nbCandidates, unsortLimit, dictMode);
305 matchIndex = nextCandidateIdx;
306 nbCandidates++;
307 }
308
309 /* find longest match */
310 { size_t commonLengthSmaller = 0, commonLengthLarger = 0;
311 const BYTE* const dictBase = ms->window.dictBase;
312 const U32 dictLimit = ms->window.dictLimit;
313 const BYTE* const dictEnd = dictBase + dictLimit;
314 const BYTE* const prefixStart = base + dictLimit;
315 U32* smallerPtr = bt + 2*(curr&btMask);
316 U32* largerPtr = bt + 2*(curr&btMask) + 1;
317 U32 matchEndIdx = curr + 8 + 1;
318 U32 dummy32; /* to be nullified at the end */
319 size_t bestLength = 0;
320
321 matchIndex = hashTable[h];
322 hashTable[h] = curr; /* Update Hash Table */
323
324 for (; nbCompares && (matchIndex > windowLow); --nbCompares) {
325 U32* const nextPtr = bt + 2*(matchIndex & btMask);
326 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
327 const BYTE* match;
328
329 if ((dictMode != ZSTD_extDict) || (matchIndex+matchLength >= dictLimit)) {
330 match = base + matchIndex;
331 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
332 } else {
333 match = dictBase + matchIndex;
334 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
335 if (matchIndex+matchLength >= dictLimit)
336 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
337 }
338
339 if (matchLength > bestLength) {
340 if (matchLength > matchEndIdx - matchIndex)
341 matchEndIdx = matchIndex + (U32)matchLength;
342 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(curr - matchIndex + 1) - ZSTD_highbit32((U32)*offBasePtr)) )
343 bestLength = matchLength, *offBasePtr = OFFSET_TO_OFFBASE(curr - matchIndex);
344 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
345 if (dictMode == ZSTD_dictMatchState) {
346 nbCompares = 0; /* in addition to avoiding checking any
347 * further in this loop, make sure we
348 * skip checking in the dictionary. */
349 }
350 break; /* drop, to guarantee consistency (miss a little bit of compression) */
351 }
352 }
353
354 if (match[matchLength] < ip[matchLength]) {
355 /* match is smaller than current */
356 *smallerPtr = matchIndex; /* update smaller idx */
357 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
358 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
359 smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
360 matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
361 } else {
362 /* match is larger than current */
363 *largerPtr = matchIndex;
364 commonLengthLarger = matchLength;
365 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
366 largerPtr = nextPtr;
367 matchIndex = nextPtr[0];
368 } }
369
370 *smallerPtr = *largerPtr = 0;
371
372 assert(nbCompares <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
373 if (dictMode == ZSTD_dictMatchState && nbCompares) {
374 bestLength = ZSTD_DUBT_findBetterDictMatch(
375 ms, ip, iend,
376 offBasePtr, bestLength, nbCompares,
377 mls, dictMode);
378 }
379
380 assert(matchEndIdx > curr+8); /* ensure nextToUpdate is increased */
381 ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */
382 if (bestLength >= MINMATCH) {
383 U32 const mIndex = curr - (U32)OFFBASE_TO_OFFSET(*offBasePtr); (void)mIndex;
384 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
385 curr, (U32)bestLength, (U32)*offBasePtr, mIndex);
386 }
387 return bestLength;
388 }
389}
390
391
392/** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
f535537f 393FORCE_INLINE_TEMPLATE
394ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
395size_t ZSTD_BtFindBestMatch( ZSTD_matchState_t* ms,
648db22b 396 const BYTE* const ip, const BYTE* const iLimit,
397 size_t* offBasePtr,
398 const U32 mls /* template */,
399 const ZSTD_dictMode_e dictMode)
400{
401 DEBUGLOG(7, "ZSTD_BtFindBestMatch");
402 if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */
403 ZSTD_updateDUBT(ms, ip, iLimit, mls);
404 return ZSTD_DUBT_findBestMatch(ms, ip, iLimit, offBasePtr, mls, dictMode);
405}
406
407/***********************************
408* Dedicated dict search
409***********************************/
410
411void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const BYTE* const ip)
412{
413 const BYTE* const base = ms->window.base;
414 U32 const target = (U32)(ip - base);
415 U32* const hashTable = ms->hashTable;
416 U32* const chainTable = ms->chainTable;
417 U32 const chainSize = 1 << ms->cParams.chainLog;
418 U32 idx = ms->nextToUpdate;
419 U32 const minChain = chainSize < target - idx ? target - chainSize : idx;
420 U32 const bucketSize = 1 << ZSTD_LAZY_DDSS_BUCKET_LOG;
421 U32 const cacheSize = bucketSize - 1;
422 U32 const chainAttempts = (1 << ms->cParams.searchLog) - cacheSize;
423 U32 const chainLimit = chainAttempts > 255 ? 255 : chainAttempts;
424
425 /* We know the hashtable is oversized by a factor of `bucketSize`.
426 * We are going to temporarily pretend `bucketSize == 1`, keeping only a
427 * single entry. We will use the rest of the space to construct a temporary
428 * chaintable.
429 */
430 U32 const hashLog = ms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG;
431 U32* const tmpHashTable = hashTable;
432 U32* const tmpChainTable = hashTable + ((size_t)1 << hashLog);
433 U32 const tmpChainSize = (U32)((1 << ZSTD_LAZY_DDSS_BUCKET_LOG) - 1) << hashLog;
434 U32 const tmpMinChain = tmpChainSize < target ? target - tmpChainSize : idx;
435 U32 hashIdx;
436
437 assert(ms->cParams.chainLog <= 24);
438 assert(ms->cParams.hashLog > ms->cParams.chainLog);
439 assert(idx != 0);
440 assert(tmpMinChain <= minChain);
441
442 /* fill conventional hash table and conventional chain table */
443 for ( ; idx < target; idx++) {
444 U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch);
445 if (idx >= tmpMinChain) {
446 tmpChainTable[idx - tmpMinChain] = hashTable[h];
447 }
448 tmpHashTable[h] = idx;
449 }
450
451 /* sort chains into ddss chain table */
452 {
453 U32 chainPos = 0;
454 for (hashIdx = 0; hashIdx < (1U << hashLog); hashIdx++) {
455 U32 count;
456 U32 countBeyondMinChain = 0;
457 U32 i = tmpHashTable[hashIdx];
458 for (count = 0; i >= tmpMinChain && count < cacheSize; count++) {
459 /* skip through the chain to the first position that won't be
460 * in the hash cache bucket */
461 if (i < minChain) {
462 countBeyondMinChain++;
463 }
464 i = tmpChainTable[i - tmpMinChain];
465 }
466 if (count == cacheSize) {
467 for (count = 0; count < chainLimit;) {
468 if (i < minChain) {
469 if (!i || ++countBeyondMinChain > cacheSize) {
470 /* only allow pulling `cacheSize` number of entries
471 * into the cache or chainTable beyond `minChain`,
472 * to replace the entries pulled out of the
473 * chainTable into the cache. This lets us reach
474 * back further without increasing the total number
475 * of entries in the chainTable, guaranteeing the
476 * DDSS chain table will fit into the space
477 * allocated for the regular one. */
478 break;
479 }
480 }
481 chainTable[chainPos++] = i;
482 count++;
483 if (i < tmpMinChain) {
484 break;
485 }
486 i = tmpChainTable[i - tmpMinChain];
487 }
488 } else {
489 count = 0;
490 }
491 if (count) {
492 tmpHashTable[hashIdx] = ((chainPos - count) << 8) + count;
493 } else {
494 tmpHashTable[hashIdx] = 0;
495 }
496 }
497 assert(chainPos <= chainSize); /* I believe this is guaranteed... */
498 }
499
500 /* move chain pointers into the last entry of each hash bucket */
501 for (hashIdx = (1 << hashLog); hashIdx; ) {
502 U32 const bucketIdx = --hashIdx << ZSTD_LAZY_DDSS_BUCKET_LOG;
503 U32 const chainPackedPointer = tmpHashTable[hashIdx];
504 U32 i;
505 for (i = 0; i < cacheSize; i++) {
506 hashTable[bucketIdx + i] = 0;
507 }
508 hashTable[bucketIdx + bucketSize - 1] = chainPackedPointer;
509 }
510
511 /* fill the buckets of the hash table */
512 for (idx = ms->nextToUpdate; idx < target; idx++) {
513 U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch)
514 << ZSTD_LAZY_DDSS_BUCKET_LOG;
515 U32 i;
516 /* Shift hash cache down 1. */
517 for (i = cacheSize - 1; i; i--)
518 hashTable[h + i] = hashTable[h + i - 1];
519 hashTable[h] = idx;
520 }
521
522 ms->nextToUpdate = target;
523}
524
525/* Returns the longest match length found in the dedicated dict search structure.
526 * If none are longer than the argument ml, then ml will be returned.
527 */
528FORCE_INLINE_TEMPLATE
529size_t ZSTD_dedicatedDictSearch_lazy_search(size_t* offsetPtr, size_t ml, U32 nbAttempts,
530 const ZSTD_matchState_t* const dms,
531 const BYTE* const ip, const BYTE* const iLimit,
532 const BYTE* const prefixStart, const U32 curr,
533 const U32 dictLimit, const size_t ddsIdx) {
534 const U32 ddsLowestIndex = dms->window.dictLimit;
535 const BYTE* const ddsBase = dms->window.base;
536 const BYTE* const ddsEnd = dms->window.nextSrc;
537 const U32 ddsSize = (U32)(ddsEnd - ddsBase);
538 const U32 ddsIndexDelta = dictLimit - ddsSize;
539 const U32 bucketSize = (1 << ZSTD_LAZY_DDSS_BUCKET_LOG);
540 const U32 bucketLimit = nbAttempts < bucketSize - 1 ? nbAttempts : bucketSize - 1;
541 U32 ddsAttempt;
542 U32 matchIndex;
543
544 for (ddsAttempt = 0; ddsAttempt < bucketSize - 1; ddsAttempt++) {
545 PREFETCH_L1(ddsBase + dms->hashTable[ddsIdx + ddsAttempt]);
546 }
547
548 {
549 U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1];
550 U32 const chainIndex = chainPackedPointer >> 8;
551
552 PREFETCH_L1(&dms->chainTable[chainIndex]);
553 }
554
555 for (ddsAttempt = 0; ddsAttempt < bucketLimit; ddsAttempt++) {
556 size_t currentMl=0;
557 const BYTE* match;
558 matchIndex = dms->hashTable[ddsIdx + ddsAttempt];
559 match = ddsBase + matchIndex;
560
561 if (!matchIndex) {
562 return ml;
563 }
564
565 /* guaranteed by table construction */
566 (void)ddsLowestIndex;
567 assert(matchIndex >= ddsLowestIndex);
568 assert(match+4 <= ddsEnd);
569 if (MEM_read32(match) == MEM_read32(ip)) {
570 /* assumption : matchIndex <= dictLimit-4 (by table construction) */
571 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4;
572 }
573
574 /* save best solution */
575 if (currentMl > ml) {
576 ml = currentMl;
577 *offsetPtr = OFFSET_TO_OFFBASE(curr - (matchIndex + ddsIndexDelta));
578 if (ip+currentMl == iLimit) {
579 /* best possible, avoids read overflow on next attempt */
580 return ml;
581 }
582 }
583 }
584
585 {
586 U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1];
587 U32 chainIndex = chainPackedPointer >> 8;
588 U32 const chainLength = chainPackedPointer & 0xFF;
589 U32 const chainAttempts = nbAttempts - ddsAttempt;
590 U32 const chainLimit = chainAttempts > chainLength ? chainLength : chainAttempts;
591 U32 chainAttempt;
592
593 for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++) {
594 PREFETCH_L1(ddsBase + dms->chainTable[chainIndex + chainAttempt]);
595 }
596
597 for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++, chainIndex++) {
598 size_t currentMl=0;
599 const BYTE* match;
600 matchIndex = dms->chainTable[chainIndex];
601 match = ddsBase + matchIndex;
602
603 /* guaranteed by table construction */
604 assert(matchIndex >= ddsLowestIndex);
605 assert(match+4 <= ddsEnd);
606 if (MEM_read32(match) == MEM_read32(ip)) {
607 /* assumption : matchIndex <= dictLimit-4 (by table construction) */
608 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4;
609 }
610
611 /* save best solution */
612 if (currentMl > ml) {
613 ml = currentMl;
614 *offsetPtr = OFFSET_TO_OFFBASE(curr - (matchIndex + ddsIndexDelta));
615 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
616 }
617 }
618 }
619 return ml;
620}
621
622
623/* *********************************
624* Hash Chain
625***********************************/
626#define NEXT_IN_CHAIN(d, mask) chainTable[(d) & (mask)]
627
628/* Update chains up to ip (excluded)
629 Assumption : always within prefix (i.e. not within extDict) */
f535537f 630FORCE_INLINE_TEMPLATE
631ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
632U32 ZSTD_insertAndFindFirstIndex_internal(
648db22b 633 ZSTD_matchState_t* ms,
634 const ZSTD_compressionParameters* const cParams,
635 const BYTE* ip, U32 const mls, U32 const lazySkipping)
636{
637 U32* const hashTable = ms->hashTable;
638 const U32 hashLog = cParams->hashLog;
639 U32* const chainTable = ms->chainTable;
640 const U32 chainMask = (1 << cParams->chainLog) - 1;
641 const BYTE* const base = ms->window.base;
642 const U32 target = (U32)(ip - base);
643 U32 idx = ms->nextToUpdate;
644
645 while(idx < target) { /* catch up */
646 size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
647 NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
648 hashTable[h] = idx;
649 idx++;
650 /* Stop inserting every position when in the lazy skipping mode. */
651 if (lazySkipping)
652 break;
653 }
654
655 ms->nextToUpdate = target;
656 return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
657}
658
659U32 ZSTD_insertAndFindFirstIndex(ZSTD_matchState_t* ms, const BYTE* ip) {
660 const ZSTD_compressionParameters* const cParams = &ms->cParams;
661 return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, ms->cParams.minMatch, /* lazySkipping*/ 0);
662}
663
664/* inlining is important to hardwire a hot branch (template emulation) */
665FORCE_INLINE_TEMPLATE
f535537f 666ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
648db22b 667size_t ZSTD_HcFindBestMatch(
668 ZSTD_matchState_t* ms,
669 const BYTE* const ip, const BYTE* const iLimit,
670 size_t* offsetPtr,
671 const U32 mls, const ZSTD_dictMode_e dictMode)
672{
673 const ZSTD_compressionParameters* const cParams = &ms->cParams;
674 U32* const chainTable = ms->chainTable;
675 const U32 chainSize = (1 << cParams->chainLog);
676 const U32 chainMask = chainSize-1;
677 const BYTE* const base = ms->window.base;
678 const BYTE* const dictBase = ms->window.dictBase;
679 const U32 dictLimit = ms->window.dictLimit;
680 const BYTE* const prefixStart = base + dictLimit;
681 const BYTE* const dictEnd = dictBase + dictLimit;
682 const U32 curr = (U32)(ip-base);
683 const U32 maxDistance = 1U << cParams->windowLog;
684 const U32 lowestValid = ms->window.lowLimit;
685 const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
686 const U32 isDictionary = (ms->loadedDictEnd != 0);
687 const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
688 const U32 minChain = curr > chainSize ? curr - chainSize : 0;
689 U32 nbAttempts = 1U << cParams->searchLog;
690 size_t ml=4-1;
691
692 const ZSTD_matchState_t* const dms = ms->dictMatchState;
693 const U32 ddsHashLog = dictMode == ZSTD_dedicatedDictSearch
694 ? dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG : 0;
695 const size_t ddsIdx = dictMode == ZSTD_dedicatedDictSearch
696 ? ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG : 0;
697
698 U32 matchIndex;
699
700 if (dictMode == ZSTD_dedicatedDictSearch) {
701 const U32* entry = &dms->hashTable[ddsIdx];
702 PREFETCH_L1(entry);
703 }
704
705 /* HC4 match finder */
706 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls, ms->lazySkipping);
707
708 for ( ; (matchIndex>=lowLimit) & (nbAttempts>0) ; nbAttempts--) {
709 size_t currentMl=0;
710 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
711 const BYTE* const match = base + matchIndex;
712 assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
713 /* read 4B starting from (match + ml + 1 - sizeof(U32)) */
714 if (MEM_read32(match + ml - 3) == MEM_read32(ip + ml - 3)) /* potentially better */
715 currentMl = ZSTD_count(ip, match, iLimit);
716 } else {
717 const BYTE* const match = dictBase + matchIndex;
718 assert(match+4 <= dictEnd);
719 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
720 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
721 }
722
723 /* save best solution */
724 if (currentMl > ml) {
725 ml = currentMl;
726 *offsetPtr = OFFSET_TO_OFFBASE(curr - matchIndex);
727 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
728 }
729
730 if (matchIndex <= minChain) break;
731 matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
732 }
733
734 assert(nbAttempts <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
735 if (dictMode == ZSTD_dedicatedDictSearch) {
736 ml = ZSTD_dedicatedDictSearch_lazy_search(offsetPtr, ml, nbAttempts, dms,
737 ip, iLimit, prefixStart, curr, dictLimit, ddsIdx);
738 } else if (dictMode == ZSTD_dictMatchState) {
739 const U32* const dmsChainTable = dms->chainTable;
740 const U32 dmsChainSize = (1 << dms->cParams.chainLog);
741 const U32 dmsChainMask = dmsChainSize - 1;
742 const U32 dmsLowestIndex = dms->window.dictLimit;
743 const BYTE* const dmsBase = dms->window.base;
744 const BYTE* const dmsEnd = dms->window.nextSrc;
745 const U32 dmsSize = (U32)(dmsEnd - dmsBase);
746 const U32 dmsIndexDelta = dictLimit - dmsSize;
747 const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0;
748
749 matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)];
750
751 for ( ; (matchIndex>=dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) {
752 size_t currentMl=0;
753 const BYTE* const match = dmsBase + matchIndex;
754 assert(match+4 <= dmsEnd);
755 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
756 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
757
758 /* save best solution */
759 if (currentMl > ml) {
760 ml = currentMl;
761 assert(curr > matchIndex + dmsIndexDelta);
762 *offsetPtr = OFFSET_TO_OFFBASE(curr - (matchIndex + dmsIndexDelta));
763 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
764 }
765
766 if (matchIndex <= dmsMinChain) break;
767
768 matchIndex = dmsChainTable[matchIndex & dmsChainMask];
769 }
770 }
771
772 return ml;
773}
774
775/* *********************************
776* (SIMD) Row-based matchfinder
777***********************************/
778/* Constants for row-based hash */
779#define ZSTD_ROW_HASH_TAG_MASK ((1u << ZSTD_ROW_HASH_TAG_BITS) - 1)
780#define ZSTD_ROW_HASH_MAX_ENTRIES 64 /* absolute maximum number of entries per row, for all configurations */
781
782#define ZSTD_ROW_HASH_CACHE_MASK (ZSTD_ROW_HASH_CACHE_SIZE - 1)
783
784typedef U64 ZSTD_VecMask; /* Clarifies when we are interacting with a U64 representing a mask of matches */
785
786/* ZSTD_VecMask_next():
787 * Starting from the LSB, returns the idx of the next non-zero bit.
788 * Basically counting the nb of trailing zeroes.
789 */
790MEM_STATIC U32 ZSTD_VecMask_next(ZSTD_VecMask val) {
791 return ZSTD_countTrailingZeros64(val);
792}
793
794/* ZSTD_row_nextIndex():
795 * Returns the next index to insert at within a tagTable row, and updates the "head"
796 * value to reflect the update. Essentially cycles backwards from [1, {entries per row})
797 */
798FORCE_INLINE_TEMPLATE U32 ZSTD_row_nextIndex(BYTE* const tagRow, U32 const rowMask) {
799 U32 next = (*tagRow-1) & rowMask;
800 next += (next == 0) ? rowMask : 0; /* skip first position */
801 *tagRow = (BYTE)next;
802 return next;
803}
804
805/* ZSTD_isAligned():
806 * Checks that a pointer is aligned to "align" bytes which must be a power of 2.
807 */
808MEM_STATIC int ZSTD_isAligned(void const* ptr, size_t align) {
809 assert((align & (align - 1)) == 0);
810 return (((size_t)ptr) & (align - 1)) == 0;
811}
812
813/* ZSTD_row_prefetch():
814 * Performs prefetching for the hashTable and tagTable at a given row.
815 */
816FORCE_INLINE_TEMPLATE void ZSTD_row_prefetch(U32 const* hashTable, BYTE const* tagTable, U32 const relRow, U32 const rowLog) {
817 PREFETCH_L1(hashTable + relRow);
818 if (rowLog >= 5) {
819 PREFETCH_L1(hashTable + relRow + 16);
820 /* Note: prefetching more of the hash table does not appear to be beneficial for 128-entry rows */
821 }
822 PREFETCH_L1(tagTable + relRow);
823 if (rowLog == 6) {
824 PREFETCH_L1(tagTable + relRow + 32);
825 }
826 assert(rowLog == 4 || rowLog == 5 || rowLog == 6);
827 assert(ZSTD_isAligned(hashTable + relRow, 64)); /* prefetched hash row always 64-byte aligned */
828 assert(ZSTD_isAligned(tagTable + relRow, (size_t)1 << rowLog)); /* prefetched tagRow sits on correct multiple of bytes (32,64,128) */
829}
830
831/* ZSTD_row_fillHashCache():
832 * Fill up the hash cache starting at idx, prefetching up to ZSTD_ROW_HASH_CACHE_SIZE entries,
833 * but not beyond iLimit.
834 */
f535537f 835FORCE_INLINE_TEMPLATE
836ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
837void ZSTD_row_fillHashCache(ZSTD_matchState_t* ms, const BYTE* base,
648db22b 838 U32 const rowLog, U32 const mls,
839 U32 idx, const BYTE* const iLimit)
840{
841 U32 const* const hashTable = ms->hashTable;
842 BYTE const* const tagTable = ms->tagTable;
843 U32 const hashLog = ms->rowHashLog;
844 U32 const maxElemsToPrefetch = (base + idx) > iLimit ? 0 : (U32)(iLimit - (base + idx) + 1);
845 U32 const lim = idx + MIN(ZSTD_ROW_HASH_CACHE_SIZE, maxElemsToPrefetch);
846
847 for (; idx < lim; ++idx) {
848 U32 const hash = (U32)ZSTD_hashPtrSalted(base + idx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls, ms->hashSalt);
849 U32 const row = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
850 ZSTD_row_prefetch(hashTable, tagTable, row, rowLog);
851 ms->hashCache[idx & ZSTD_ROW_HASH_CACHE_MASK] = hash;
852 }
853
854 DEBUGLOG(6, "ZSTD_row_fillHashCache(): [%u %u %u %u %u %u %u %u]", ms->hashCache[0], ms->hashCache[1],
855 ms->hashCache[2], ms->hashCache[3], ms->hashCache[4],
856 ms->hashCache[5], ms->hashCache[6], ms->hashCache[7]);
857}
858
859/* ZSTD_row_nextCachedHash():
860 * Returns the hash of base + idx, and replaces the hash in the hash cache with the byte at
861 * base + idx + ZSTD_ROW_HASH_CACHE_SIZE. Also prefetches the appropriate rows from hashTable and tagTable.
862 */
f535537f 863FORCE_INLINE_TEMPLATE
864ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
865U32 ZSTD_row_nextCachedHash(U32* cache, U32 const* hashTable,
648db22b 866 BYTE const* tagTable, BYTE const* base,
867 U32 idx, U32 const hashLog,
868 U32 const rowLog, U32 const mls,
869 U64 const hashSalt)
870{
871 U32 const newHash = (U32)ZSTD_hashPtrSalted(base+idx+ZSTD_ROW_HASH_CACHE_SIZE, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls, hashSalt);
872 U32 const row = (newHash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
873 ZSTD_row_prefetch(hashTable, tagTable, row, rowLog);
874 { U32 const hash = cache[idx & ZSTD_ROW_HASH_CACHE_MASK];
875 cache[idx & ZSTD_ROW_HASH_CACHE_MASK] = newHash;
876 return hash;
877 }
878}
879
880/* ZSTD_row_update_internalImpl():
881 * Updates the hash table with positions starting from updateStartIdx until updateEndIdx.
882 */
f535537f 883FORCE_INLINE_TEMPLATE
884ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
885void ZSTD_row_update_internalImpl(ZSTD_matchState_t* ms,
886 U32 updateStartIdx, U32 const updateEndIdx,
887 U32 const mls, U32 const rowLog,
888 U32 const rowMask, U32 const useCache)
648db22b 889{
890 U32* const hashTable = ms->hashTable;
891 BYTE* const tagTable = ms->tagTable;
892 U32 const hashLog = ms->rowHashLog;
893 const BYTE* const base = ms->window.base;
894
895 DEBUGLOG(6, "ZSTD_row_update_internalImpl(): updateStartIdx=%u, updateEndIdx=%u", updateStartIdx, updateEndIdx);
896 for (; updateStartIdx < updateEndIdx; ++updateStartIdx) {
897 U32 const hash = useCache ? ZSTD_row_nextCachedHash(ms->hashCache, hashTable, tagTable, base, updateStartIdx, hashLog, rowLog, mls, ms->hashSalt)
898 : (U32)ZSTD_hashPtrSalted(base + updateStartIdx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls, ms->hashSalt);
899 U32 const relRow = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
900 U32* const row = hashTable + relRow;
901 BYTE* tagRow = tagTable + relRow;
902 U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
903
904 assert(hash == ZSTD_hashPtrSalted(base + updateStartIdx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls, ms->hashSalt));
905 tagRow[pos] = hash & ZSTD_ROW_HASH_TAG_MASK;
906 row[pos] = updateStartIdx;
907 }
908}
909
910/* ZSTD_row_update_internal():
911 * Inserts the byte at ip into the appropriate position in the hash table, and updates ms->nextToUpdate.
912 * Skips sections of long matches as is necessary.
913 */
f535537f 914FORCE_INLINE_TEMPLATE
915ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
916void ZSTD_row_update_internal(ZSTD_matchState_t* ms, const BYTE* ip,
917 U32 const mls, U32 const rowLog,
918 U32 const rowMask, U32 const useCache)
648db22b 919{
920 U32 idx = ms->nextToUpdate;
921 const BYTE* const base = ms->window.base;
922 const U32 target = (U32)(ip - base);
923 const U32 kSkipThreshold = 384;
924 const U32 kMaxMatchStartPositionsToUpdate = 96;
925 const U32 kMaxMatchEndPositionsToUpdate = 32;
926
927 if (useCache) {
928 /* Only skip positions when using hash cache, i.e.
929 * if we are loading a dict, don't skip anything.
930 * If we decide to skip, then we only update a set number
931 * of positions at the beginning and end of the match.
932 */
933 if (UNLIKELY(target - idx > kSkipThreshold)) {
934 U32 const bound = idx + kMaxMatchStartPositionsToUpdate;
935 ZSTD_row_update_internalImpl(ms, idx, bound, mls, rowLog, rowMask, useCache);
936 idx = target - kMaxMatchEndPositionsToUpdate;
937 ZSTD_row_fillHashCache(ms, base, rowLog, mls, idx, ip+1);
938 }
939 }
940 assert(target >= idx);
941 ZSTD_row_update_internalImpl(ms, idx, target, mls, rowLog, rowMask, useCache);
942 ms->nextToUpdate = target;
943}
944
945/* ZSTD_row_update():
946 * External wrapper for ZSTD_row_update_internal(). Used for filling the hashtable during dictionary
947 * processing.
948 */
949void ZSTD_row_update(ZSTD_matchState_t* const ms, const BYTE* ip) {
950 const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
951 const U32 rowMask = (1u << rowLog) - 1;
952 const U32 mls = MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */);
953
954 DEBUGLOG(5, "ZSTD_row_update(), rowLog=%u", rowLog);
955 ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 0 /* don't use cache */);
956}
957
958/* Returns the mask width of bits group of which will be set to 1. Given not all
959 * architectures have easy movemask instruction, this helps to iterate over
960 * groups of bits easier and faster.
961 */
962FORCE_INLINE_TEMPLATE U32
963ZSTD_row_matchMaskGroupWidth(const U32 rowEntries)
964{
965 assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64);
966 assert(rowEntries <= ZSTD_ROW_HASH_MAX_ENTRIES);
967 (void)rowEntries;
968#if defined(ZSTD_ARCH_ARM_NEON)
969 /* NEON path only works for little endian */
970 if (!MEM_isLittleEndian()) {
971 return 1;
972 }
973 if (rowEntries == 16) {
974 return 4;
975 }
976 if (rowEntries == 32) {
977 return 2;
978 }
979 if (rowEntries == 64) {
980 return 1;
981 }
982#endif
983 return 1;
984}
985
986#if defined(ZSTD_ARCH_X86_SSE2)
987FORCE_INLINE_TEMPLATE ZSTD_VecMask
988ZSTD_row_getSSEMask(int nbChunks, const BYTE* const src, const BYTE tag, const U32 head)
989{
990 const __m128i comparisonMask = _mm_set1_epi8((char)tag);
991 int matches[4] = {0};
992 int i;
993 assert(nbChunks == 1 || nbChunks == 2 || nbChunks == 4);
994 for (i=0; i<nbChunks; i++) {
995 const __m128i chunk = _mm_loadu_si128((const __m128i*)(const void*)(src + 16*i));
996 const __m128i equalMask = _mm_cmpeq_epi8(chunk, comparisonMask);
997 matches[i] = _mm_movemask_epi8(equalMask);
998 }
999 if (nbChunks == 1) return ZSTD_rotateRight_U16((U16)matches[0], head);
1000 if (nbChunks == 2) return ZSTD_rotateRight_U32((U32)matches[1] << 16 | (U32)matches[0], head);
1001 assert(nbChunks == 4);
1002 return ZSTD_rotateRight_U64((U64)matches[3] << 48 | (U64)matches[2] << 32 | (U64)matches[1] << 16 | (U64)matches[0], head);
1003}
1004#endif
1005
1006#if defined(ZSTD_ARCH_ARM_NEON)
1007FORCE_INLINE_TEMPLATE ZSTD_VecMask
1008ZSTD_row_getNEONMask(const U32 rowEntries, const BYTE* const src, const BYTE tag, const U32 headGrouped)
1009{
1010 assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64);
1011 if (rowEntries == 16) {
1012 /* vshrn_n_u16 shifts by 4 every u16 and narrows to 8 lower bits.
1013 * After that groups of 4 bits represent the equalMask. We lower
1014 * all bits except the highest in these groups by doing AND with
1015 * 0x88 = 0b10001000.
1016 */
1017 const uint8x16_t chunk = vld1q_u8(src);
1018 const uint16x8_t equalMask = vreinterpretq_u16_u8(vceqq_u8(chunk, vdupq_n_u8(tag)));
1019 const uint8x8_t res = vshrn_n_u16(equalMask, 4);
1020 const U64 matches = vget_lane_u64(vreinterpret_u64_u8(res), 0);
1021 return ZSTD_rotateRight_U64(matches, headGrouped) & 0x8888888888888888ull;
1022 } else if (rowEntries == 32) {
1023 /* Same idea as with rowEntries == 16 but doing AND with
1024 * 0x55 = 0b01010101.
1025 */
1026 const uint16x8x2_t chunk = vld2q_u16((const uint16_t*)(const void*)src);
1027 const uint8x16_t chunk0 = vreinterpretq_u8_u16(chunk.val[0]);
1028 const uint8x16_t chunk1 = vreinterpretq_u8_u16(chunk.val[1]);
1029 const uint8x16_t dup = vdupq_n_u8(tag);
1030 const uint8x8_t t0 = vshrn_n_u16(vreinterpretq_u16_u8(vceqq_u8(chunk0, dup)), 6);
1031 const uint8x8_t t1 = vshrn_n_u16(vreinterpretq_u16_u8(vceqq_u8(chunk1, dup)), 6);
1032 const uint8x8_t res = vsli_n_u8(t0, t1, 4);
1033 const U64 matches = vget_lane_u64(vreinterpret_u64_u8(res), 0) ;
1034 return ZSTD_rotateRight_U64(matches, headGrouped) & 0x5555555555555555ull;
1035 } else { /* rowEntries == 64 */
1036 const uint8x16x4_t chunk = vld4q_u8(src);
1037 const uint8x16_t dup = vdupq_n_u8(tag);
1038 const uint8x16_t cmp0 = vceqq_u8(chunk.val[0], dup);
1039 const uint8x16_t cmp1 = vceqq_u8(chunk.val[1], dup);
1040 const uint8x16_t cmp2 = vceqq_u8(chunk.val[2], dup);
1041 const uint8x16_t cmp3 = vceqq_u8(chunk.val[3], dup);
1042
1043 const uint8x16_t t0 = vsriq_n_u8(cmp1, cmp0, 1);
1044 const uint8x16_t t1 = vsriq_n_u8(cmp3, cmp2, 1);
1045 const uint8x16_t t2 = vsriq_n_u8(t1, t0, 2);
1046 const uint8x16_t t3 = vsriq_n_u8(t2, t2, 4);
1047 const uint8x8_t t4 = vshrn_n_u16(vreinterpretq_u16_u8(t3), 4);
1048 const U64 matches = vget_lane_u64(vreinterpret_u64_u8(t4), 0);
1049 return ZSTD_rotateRight_U64(matches, headGrouped);
1050 }
1051}
1052#endif
1053
1054/* Returns a ZSTD_VecMask (U64) that has the nth group (determined by
1055 * ZSTD_row_matchMaskGroupWidth) of bits set to 1 if the newly-computed "tag"
1056 * matches the hash at the nth position in a row of the tagTable.
1057 * Each row is a circular buffer beginning at the value of "headGrouped". So we
1058 * must rotate the "matches" bitfield to match up with the actual layout of the
1059 * entries within the hashTable */
1060FORCE_INLINE_TEMPLATE ZSTD_VecMask
1061ZSTD_row_getMatchMask(const BYTE* const tagRow, const BYTE tag, const U32 headGrouped, const U32 rowEntries)
1062{
1063 const BYTE* const src = tagRow;
1064 assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64);
1065 assert(rowEntries <= ZSTD_ROW_HASH_MAX_ENTRIES);
1066 assert(ZSTD_row_matchMaskGroupWidth(rowEntries) * rowEntries <= sizeof(ZSTD_VecMask) * 8);
1067
1068#if defined(ZSTD_ARCH_X86_SSE2)
1069
1070 return ZSTD_row_getSSEMask(rowEntries / 16, src, tag, headGrouped);
1071
1072#else /* SW or NEON-LE */
1073
1074# if defined(ZSTD_ARCH_ARM_NEON)
1075 /* This NEON path only works for little endian - otherwise use SWAR below */
1076 if (MEM_isLittleEndian()) {
1077 return ZSTD_row_getNEONMask(rowEntries, src, tag, headGrouped);
1078 }
1079# endif /* ZSTD_ARCH_ARM_NEON */
1080 /* SWAR */
1081 { const int chunkSize = sizeof(size_t);
1082 const size_t shiftAmount = ((chunkSize * 8) - chunkSize);
1083 const size_t xFF = ~((size_t)0);
1084 const size_t x01 = xFF / 0xFF;
1085 const size_t x80 = x01 << 7;
1086 const size_t splatChar = tag * x01;
1087 ZSTD_VecMask matches = 0;
1088 int i = rowEntries - chunkSize;
1089 assert((sizeof(size_t) == 4) || (sizeof(size_t) == 8));
1090 if (MEM_isLittleEndian()) { /* runtime check so have two loops */
1091 const size_t extractMagic = (xFF / 0x7F) >> chunkSize;
1092 do {
1093 size_t chunk = MEM_readST(&src[i]);
1094 chunk ^= splatChar;
1095 chunk = (((chunk | x80) - x01) | chunk) & x80;
1096 matches <<= chunkSize;
1097 matches |= (chunk * extractMagic) >> shiftAmount;
1098 i -= chunkSize;
1099 } while (i >= 0);
1100 } else { /* big endian: reverse bits during extraction */
1101 const size_t msb = xFF ^ (xFF >> 1);
1102 const size_t extractMagic = (msb / 0x1FF) | msb;
1103 do {
1104 size_t chunk = MEM_readST(&src[i]);
1105 chunk ^= splatChar;
1106 chunk = (((chunk | x80) - x01) | chunk) & x80;
1107 matches <<= chunkSize;
1108 matches |= ((chunk >> 7) * extractMagic) >> shiftAmount;
1109 i -= chunkSize;
1110 } while (i >= 0);
1111 }
1112 matches = ~matches;
1113 if (rowEntries == 16) {
1114 return ZSTD_rotateRight_U16((U16)matches, headGrouped);
1115 } else if (rowEntries == 32) {
1116 return ZSTD_rotateRight_U32((U32)matches, headGrouped);
1117 } else {
1118 return ZSTD_rotateRight_U64((U64)matches, headGrouped);
1119 }
1120 }
1121#endif
1122}
1123
1124/* The high-level approach of the SIMD row based match finder is as follows:
1125 * - Figure out where to insert the new entry:
f535537f 1126 * - Generate a hash for current input posistion and split it into a one byte of tag and `rowHashLog` bits of index.
1127 * - The hash is salted by a value that changes on every contex reset, so when the same table is used
1128 * we will avoid collisions that would otherwise slow us down by intorducing phantom matches.
1129 * - The hashTable is effectively split into groups or "rows" of 15 or 31 entries of U32, and the index determines
648db22b 1130 * which row to insert into.
f535537f 1131 * - Determine the correct position within the row to insert the entry into. Each row of 15 or 31 can
1132 * be considered as a circular buffer with a "head" index that resides in the tagTable (overall 16 or 32 bytes
1133 * per row).
1134 * - Use SIMD to efficiently compare the tags in the tagTable to the 1-byte tag calculated for the position and
648db22b 1135 * generate a bitfield that we can cycle through to check the collisions in the hash table.
1136 * - Pick the longest match.
f535537f 1137 * - Insert the tag into the equivalent row and position in the tagTable.
648db22b 1138 */
1139FORCE_INLINE_TEMPLATE
f535537f 1140ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
648db22b 1141size_t ZSTD_RowFindBestMatch(
1142 ZSTD_matchState_t* ms,
1143 const BYTE* const ip, const BYTE* const iLimit,
1144 size_t* offsetPtr,
1145 const U32 mls, const ZSTD_dictMode_e dictMode,
1146 const U32 rowLog)
1147{
1148 U32* const hashTable = ms->hashTable;
1149 BYTE* const tagTable = ms->tagTable;
1150 U32* const hashCache = ms->hashCache;
1151 const U32 hashLog = ms->rowHashLog;
1152 const ZSTD_compressionParameters* const cParams = &ms->cParams;
1153 const BYTE* const base = ms->window.base;
1154 const BYTE* const dictBase = ms->window.dictBase;
1155 const U32 dictLimit = ms->window.dictLimit;
1156 const BYTE* const prefixStart = base + dictLimit;
1157 const BYTE* const dictEnd = dictBase + dictLimit;
1158 const U32 curr = (U32)(ip-base);
1159 const U32 maxDistance = 1U << cParams->windowLog;
1160 const U32 lowestValid = ms->window.lowLimit;
1161 const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
1162 const U32 isDictionary = (ms->loadedDictEnd != 0);
1163 const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
1164 const U32 rowEntries = (1U << rowLog);
1165 const U32 rowMask = rowEntries - 1;
1166 const U32 cappedSearchLog = MIN(cParams->searchLog, rowLog); /* nb of searches is capped at nb entries per row */
1167 const U32 groupWidth = ZSTD_row_matchMaskGroupWidth(rowEntries);
1168 const U64 hashSalt = ms->hashSalt;
1169 U32 nbAttempts = 1U << cappedSearchLog;
1170 size_t ml=4-1;
1171 U32 hash;
1172
1173 /* DMS/DDS variables that may be referenced laster */
1174 const ZSTD_matchState_t* const dms = ms->dictMatchState;
1175
1176 /* Initialize the following variables to satisfy static analyzer */
1177 size_t ddsIdx = 0;
1178 U32 ddsExtraAttempts = 0; /* cctx hash tables are limited in searches, but allow extra searches into DDS */
1179 U32 dmsTag = 0;
1180 U32* dmsRow = NULL;
1181 BYTE* dmsTagRow = NULL;
1182
1183 if (dictMode == ZSTD_dedicatedDictSearch) {
1184 const U32 ddsHashLog = dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG;
1185 { /* Prefetch DDS hashtable entry */
1186 ddsIdx = ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG;
1187 PREFETCH_L1(&dms->hashTable[ddsIdx]);
1188 }
1189 ddsExtraAttempts = cParams->searchLog > rowLog ? 1U << (cParams->searchLog - rowLog) : 0;
1190 }
1191
1192 if (dictMode == ZSTD_dictMatchState) {
1193 /* Prefetch DMS rows */
1194 U32* const dmsHashTable = dms->hashTable;
1195 BYTE* const dmsTagTable = dms->tagTable;
1196 U32 const dmsHash = (U32)ZSTD_hashPtr(ip, dms->rowHashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
1197 U32 const dmsRelRow = (dmsHash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
1198 dmsTag = dmsHash & ZSTD_ROW_HASH_TAG_MASK;
1199 dmsTagRow = (BYTE*)(dmsTagTable + dmsRelRow);
1200 dmsRow = dmsHashTable + dmsRelRow;
1201 ZSTD_row_prefetch(dmsHashTable, dmsTagTable, dmsRelRow, rowLog);
1202 }
1203
1204 /* Update the hashTable and tagTable up to (but not including) ip */
1205 if (!ms->lazySkipping) {
1206 ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 1 /* useCache */);
1207 hash = ZSTD_row_nextCachedHash(hashCache, hashTable, tagTable, base, curr, hashLog, rowLog, mls, hashSalt);
1208 } else {
1209 /* Stop inserting every position when in the lazy skipping mode.
1210 * The hash cache is also not kept up to date in this mode.
1211 */
1212 hash = (U32)ZSTD_hashPtrSalted(ip, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls, hashSalt);
1213 ms->nextToUpdate = curr;
1214 }
1215 ms->hashSaltEntropy += hash; /* collect salt entropy */
1216
1217 { /* Get the hash for ip, compute the appropriate row */
1218 U32 const relRow = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
1219 U32 const tag = hash & ZSTD_ROW_HASH_TAG_MASK;
1220 U32* const row = hashTable + relRow;
1221 BYTE* tagRow = (BYTE*)(tagTable + relRow);
1222 U32 const headGrouped = (*tagRow & rowMask) * groupWidth;
1223 U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES];
1224 size_t numMatches = 0;
1225 size_t currMatch = 0;
1226 ZSTD_VecMask matches = ZSTD_row_getMatchMask(tagRow, (BYTE)tag, headGrouped, rowEntries);
1227
1228 /* Cycle through the matches and prefetch */
1229 for (; (matches > 0) && (nbAttempts > 0); matches &= (matches - 1)) {
1230 U32 const matchPos = ((headGrouped + ZSTD_VecMask_next(matches)) / groupWidth) & rowMask;
1231 U32 const matchIndex = row[matchPos];
1232 if(matchPos == 0) continue;
1233 assert(numMatches < rowEntries);
1234 if (matchIndex < lowLimit)
1235 break;
1236 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
1237 PREFETCH_L1(base + matchIndex);
1238 } else {
1239 PREFETCH_L1(dictBase + matchIndex);
1240 }
1241 matchBuffer[numMatches++] = matchIndex;
1242 --nbAttempts;
1243 }
1244
1245 /* Speed opt: insert current byte into hashtable too. This allows us to avoid one iteration of the loop
1246 in ZSTD_row_update_internal() at the next search. */
1247 {
1248 U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
1249 tagRow[pos] = (BYTE)tag;
1250 row[pos] = ms->nextToUpdate++;
1251 }
1252
1253 /* Return the longest match */
1254 for (; currMatch < numMatches; ++currMatch) {
1255 U32 const matchIndex = matchBuffer[currMatch];
1256 size_t currentMl=0;
1257 assert(matchIndex < curr);
1258 assert(matchIndex >= lowLimit);
1259
1260 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
1261 const BYTE* const match = base + matchIndex;
1262 assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
1263 /* read 4B starting from (match + ml + 1 - sizeof(U32)) */
1264 if (MEM_read32(match + ml - 3) == MEM_read32(ip + ml - 3)) /* potentially better */
1265 currentMl = ZSTD_count(ip, match, iLimit);
1266 } else {
1267 const BYTE* const match = dictBase + matchIndex;
1268 assert(match+4 <= dictEnd);
1269 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
1270 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
1271 }
1272
1273 /* Save best solution */
1274 if (currentMl > ml) {
1275 ml = currentMl;
1276 *offsetPtr = OFFSET_TO_OFFBASE(curr - matchIndex);
1277 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
1278 }
1279 }
1280 }
1281
1282 assert(nbAttempts <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
1283 if (dictMode == ZSTD_dedicatedDictSearch) {
1284 ml = ZSTD_dedicatedDictSearch_lazy_search(offsetPtr, ml, nbAttempts + ddsExtraAttempts, dms,
1285 ip, iLimit, prefixStart, curr, dictLimit, ddsIdx);
1286 } else if (dictMode == ZSTD_dictMatchState) {
1287 /* TODO: Measure and potentially add prefetching to DMS */
1288 const U32 dmsLowestIndex = dms->window.dictLimit;
1289 const BYTE* const dmsBase = dms->window.base;
1290 const BYTE* const dmsEnd = dms->window.nextSrc;
1291 const U32 dmsSize = (U32)(dmsEnd - dmsBase);
1292 const U32 dmsIndexDelta = dictLimit - dmsSize;
1293
1294 { U32 const headGrouped = (*dmsTagRow & rowMask) * groupWidth;
1295 U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES];
1296 size_t numMatches = 0;
1297 size_t currMatch = 0;
1298 ZSTD_VecMask matches = ZSTD_row_getMatchMask(dmsTagRow, (BYTE)dmsTag, headGrouped, rowEntries);
1299
1300 for (; (matches > 0) && (nbAttempts > 0); matches &= (matches - 1)) {
1301 U32 const matchPos = ((headGrouped + ZSTD_VecMask_next(matches)) / groupWidth) & rowMask;
1302 U32 const matchIndex = dmsRow[matchPos];
1303 if(matchPos == 0) continue;
1304 if (matchIndex < dmsLowestIndex)
1305 break;
1306 PREFETCH_L1(dmsBase + matchIndex);
1307 matchBuffer[numMatches++] = matchIndex;
1308 --nbAttempts;
1309 }
1310
1311 /* Return the longest match */
1312 for (; currMatch < numMatches; ++currMatch) {
1313 U32 const matchIndex = matchBuffer[currMatch];
1314 size_t currentMl=0;
1315 assert(matchIndex >= dmsLowestIndex);
1316 assert(matchIndex < curr);
1317
1318 { const BYTE* const match = dmsBase + matchIndex;
1319 assert(match+4 <= dmsEnd);
1320 if (MEM_read32(match) == MEM_read32(ip))
1321 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
1322 }
1323
1324 if (currentMl > ml) {
1325 ml = currentMl;
1326 assert(curr > matchIndex + dmsIndexDelta);
1327 *offsetPtr = OFFSET_TO_OFFBASE(curr - (matchIndex + dmsIndexDelta));
1328 if (ip+currentMl == iLimit) break;
1329 }
1330 }
1331 }
1332 }
1333 return ml;
1334}
1335
1336
1337/**
1338 * Generate search functions templated on (dictMode, mls, rowLog).
1339 * These functions are outlined for code size & compilation time.
1340 * ZSTD_searchMax() dispatches to the correct implementation function.
1341 *
1342 * TODO: The start of the search function involves loading and calculating a
1343 * bunch of constants from the ZSTD_matchState_t. These computations could be
1344 * done in an initialization function, and saved somewhere in the match state.
1345 * Then we could pass a pointer to the saved state instead of the match state,
1346 * and avoid duplicate computations.
1347 *
1348 * TODO: Move the match re-winding into searchMax. This improves compression
1349 * ratio, and unlocks further simplifications with the next TODO.
1350 *
1351 * TODO: Try moving the repcode search into searchMax. After the re-winding
1352 * and repcode search are in searchMax, there is no more logic in the match
1353 * finder loop that requires knowledge about the dictMode. So we should be
1354 * able to avoid force inlining it, and we can join the extDict loop with
1355 * the single segment loop. It should go in searchMax instead of its own
1356 * function to avoid having multiple virtual function calls per search.
1357 */
1358
1359#define ZSTD_BT_SEARCH_FN(dictMode, mls) ZSTD_BtFindBestMatch_##dictMode##_##mls
1360#define ZSTD_HC_SEARCH_FN(dictMode, mls) ZSTD_HcFindBestMatch_##dictMode##_##mls
1361#define ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog) ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog
1362
1363#define ZSTD_SEARCH_FN_ATTRS FORCE_NOINLINE
1364
1365#define GEN_ZSTD_BT_SEARCH_FN(dictMode, mls) \
1366 ZSTD_SEARCH_FN_ATTRS size_t ZSTD_BT_SEARCH_FN(dictMode, mls)( \
1367 ZSTD_matchState_t* ms, \
1368 const BYTE* ip, const BYTE* const iLimit, \
1369 size_t* offBasePtr) \
1370 { \
1371 assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \
1372 return ZSTD_BtFindBestMatch(ms, ip, iLimit, offBasePtr, mls, ZSTD_##dictMode); \
1373 } \
1374
1375#define GEN_ZSTD_HC_SEARCH_FN(dictMode, mls) \
1376 ZSTD_SEARCH_FN_ATTRS size_t ZSTD_HC_SEARCH_FN(dictMode, mls)( \
1377 ZSTD_matchState_t* ms, \
1378 const BYTE* ip, const BYTE* const iLimit, \
1379 size_t* offsetPtr) \
1380 { \
1381 assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \
1382 return ZSTD_HcFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode); \
1383 } \
1384
1385#define GEN_ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog) \
1386 ZSTD_SEARCH_FN_ATTRS size_t ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog)( \
1387 ZSTD_matchState_t* ms, \
1388 const BYTE* ip, const BYTE* const iLimit, \
1389 size_t* offsetPtr) \
1390 { \
1391 assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \
1392 assert(MAX(4, MIN(6, ms->cParams.searchLog)) == rowLog); \
1393 return ZSTD_RowFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode, rowLog); \
1394 } \
1395
1396#define ZSTD_FOR_EACH_ROWLOG(X, dictMode, mls) \
1397 X(dictMode, mls, 4) \
1398 X(dictMode, mls, 5) \
1399 X(dictMode, mls, 6)
1400
1401#define ZSTD_FOR_EACH_MLS_ROWLOG(X, dictMode) \
1402 ZSTD_FOR_EACH_ROWLOG(X, dictMode, 4) \
1403 ZSTD_FOR_EACH_ROWLOG(X, dictMode, 5) \
1404 ZSTD_FOR_EACH_ROWLOG(X, dictMode, 6)
1405
1406#define ZSTD_FOR_EACH_MLS(X, dictMode) \
1407 X(dictMode, 4) \
1408 X(dictMode, 5) \
1409 X(dictMode, 6)
1410
1411#define ZSTD_FOR_EACH_DICT_MODE(X, ...) \
1412 X(__VA_ARGS__, noDict) \
1413 X(__VA_ARGS__, extDict) \
1414 X(__VA_ARGS__, dictMatchState) \
1415 X(__VA_ARGS__, dedicatedDictSearch)
1416
1417/* Generate row search fns for each combination of (dictMode, mls, rowLog) */
1418ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS_ROWLOG, GEN_ZSTD_ROW_SEARCH_FN)
1419/* Generate binary Tree search fns for each combination of (dictMode, mls) */
1420ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_BT_SEARCH_FN)
1421/* Generate hash chain search fns for each combination of (dictMode, mls) */
1422ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_HC_SEARCH_FN)
1423
1424typedef enum { search_hashChain=0, search_binaryTree=1, search_rowHash=2 } searchMethod_e;
1425
1426#define GEN_ZSTD_CALL_BT_SEARCH_FN(dictMode, mls) \
1427 case mls: \
1428 return ZSTD_BT_SEARCH_FN(dictMode, mls)(ms, ip, iend, offsetPtr);
1429#define GEN_ZSTD_CALL_HC_SEARCH_FN(dictMode, mls) \
1430 case mls: \
1431 return ZSTD_HC_SEARCH_FN(dictMode, mls)(ms, ip, iend, offsetPtr);
1432#define GEN_ZSTD_CALL_ROW_SEARCH_FN(dictMode, mls, rowLog) \
1433 case rowLog: \
1434 return ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog)(ms, ip, iend, offsetPtr);
1435
1436#define ZSTD_SWITCH_MLS(X, dictMode) \
1437 switch (mls) { \
1438 ZSTD_FOR_EACH_MLS(X, dictMode) \
1439 }
1440
1441#define ZSTD_SWITCH_ROWLOG(dictMode, mls) \
1442 case mls: \
1443 switch (rowLog) { \
1444 ZSTD_FOR_EACH_ROWLOG(GEN_ZSTD_CALL_ROW_SEARCH_FN, dictMode, mls) \
1445 } \
1446 ZSTD_UNREACHABLE; \
1447 break;
1448
1449#define ZSTD_SWITCH_SEARCH_METHOD(dictMode) \
1450 switch (searchMethod) { \
1451 case search_hashChain: \
1452 ZSTD_SWITCH_MLS(GEN_ZSTD_CALL_HC_SEARCH_FN, dictMode) \
1453 break; \
1454 case search_binaryTree: \
1455 ZSTD_SWITCH_MLS(GEN_ZSTD_CALL_BT_SEARCH_FN, dictMode) \
1456 break; \
1457 case search_rowHash: \
1458 ZSTD_SWITCH_MLS(ZSTD_SWITCH_ROWLOG, dictMode) \
1459 break; \
1460 } \
1461 ZSTD_UNREACHABLE;
1462
1463/**
1464 * Searches for the longest match at @p ip.
1465 * Dispatches to the correct implementation function based on the
1466 * (searchMethod, dictMode, mls, rowLog). We use switch statements
1467 * here instead of using an indirect function call through a function
1468 * pointer because after Spectre and Meltdown mitigations, indirect
1469 * function calls can be very costly, especially in the kernel.
1470 *
1471 * NOTE: dictMode and searchMethod should be templated, so those switch
1472 * statements should be optimized out. Only the mls & rowLog switches
1473 * should be left.
1474 *
1475 * @param ms The match state.
1476 * @param ip The position to search at.
1477 * @param iend The end of the input data.
1478 * @param[out] offsetPtr Stores the match offset into this pointer.
1479 * @param mls The minimum search length, in the range [4, 6].
1480 * @param rowLog The row log (if applicable), in the range [4, 6].
1481 * @param searchMethod The search method to use (templated).
1482 * @param dictMode The dictMode (templated).
1483 *
1484 * @returns The length of the longest match found, or < mls if no match is found.
1485 * If a match is found its offset is stored in @p offsetPtr.
1486 */
1487FORCE_INLINE_TEMPLATE size_t ZSTD_searchMax(
1488 ZSTD_matchState_t* ms,
1489 const BYTE* ip,
1490 const BYTE* iend,
1491 size_t* offsetPtr,
1492 U32 const mls,
1493 U32 const rowLog,
1494 searchMethod_e const searchMethod,
1495 ZSTD_dictMode_e const dictMode)
1496{
1497 if (dictMode == ZSTD_noDict) {
1498 ZSTD_SWITCH_SEARCH_METHOD(noDict)
1499 } else if (dictMode == ZSTD_extDict) {
1500 ZSTD_SWITCH_SEARCH_METHOD(extDict)
1501 } else if (dictMode == ZSTD_dictMatchState) {
1502 ZSTD_SWITCH_SEARCH_METHOD(dictMatchState)
1503 } else if (dictMode == ZSTD_dedicatedDictSearch) {
1504 ZSTD_SWITCH_SEARCH_METHOD(dedicatedDictSearch)
1505 }
1506 ZSTD_UNREACHABLE;
1507 return 0;
1508}
1509
1510/* *******************************
1511* Common parser - lazy strategy
1512*********************************/
1513
f535537f 1514FORCE_INLINE_TEMPLATE
1515ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
1516size_t ZSTD_compressBlock_lazy_generic(
648db22b 1517 ZSTD_matchState_t* ms, seqStore_t* seqStore,
1518 U32 rep[ZSTD_REP_NUM],
1519 const void* src, size_t srcSize,
1520 const searchMethod_e searchMethod, const U32 depth,
1521 ZSTD_dictMode_e const dictMode)
1522{
1523 const BYTE* const istart = (const BYTE*)src;
1524 const BYTE* ip = istart;
1525 const BYTE* anchor = istart;
1526 const BYTE* const iend = istart + srcSize;
1527 const BYTE* const ilimit = (searchMethod == search_rowHash) ? iend - 8 - ZSTD_ROW_HASH_CACHE_SIZE : iend - 8;
1528 const BYTE* const base = ms->window.base;
1529 const U32 prefixLowestIndex = ms->window.dictLimit;
1530 const BYTE* const prefixLowest = base + prefixLowestIndex;
1531 const U32 mls = BOUNDED(4, ms->cParams.minMatch, 6);
1532 const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
1533
1534 U32 offset_1 = rep[0], offset_2 = rep[1];
1535 U32 offsetSaved1 = 0, offsetSaved2 = 0;
1536
1537 const int isDMS = dictMode == ZSTD_dictMatchState;
1538 const int isDDS = dictMode == ZSTD_dedicatedDictSearch;
1539 const int isDxS = isDMS || isDDS;
1540 const ZSTD_matchState_t* const dms = ms->dictMatchState;
1541 const U32 dictLowestIndex = isDxS ? dms->window.dictLimit : 0;
1542 const BYTE* const dictBase = isDxS ? dms->window.base : NULL;
1543 const BYTE* const dictLowest = isDxS ? dictBase + dictLowestIndex : NULL;
1544 const BYTE* const dictEnd = isDxS ? dms->window.nextSrc : NULL;
1545 const U32 dictIndexDelta = isDxS ?
1546 prefixLowestIndex - (U32)(dictEnd - dictBase) :
1547 0;
1548 const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
1549
1550 DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u) (searchFunc=%u)", (U32)dictMode, (U32)searchMethod);
1551 ip += (dictAndPrefixLength == 0);
1552 if (dictMode == ZSTD_noDict) {
1553 U32 const curr = (U32)(ip - base);
1554 U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, ms->cParams.windowLog);
1555 U32 const maxRep = curr - windowLow;
1556 if (offset_2 > maxRep) offsetSaved2 = offset_2, offset_2 = 0;
1557 if (offset_1 > maxRep) offsetSaved1 = offset_1, offset_1 = 0;
1558 }
1559 if (isDxS) {
1560 /* dictMatchState repCode checks don't currently handle repCode == 0
1561 * disabling. */
1562 assert(offset_1 <= dictAndPrefixLength);
1563 assert(offset_2 <= dictAndPrefixLength);
1564 }
1565
1566 /* Reset the lazy skipping state */
1567 ms->lazySkipping = 0;
1568
1569 if (searchMethod == search_rowHash) {
1570 ZSTD_row_fillHashCache(ms, base, rowLog, mls, ms->nextToUpdate, ilimit);
1571 }
1572
1573 /* Match Loop */
1574#if defined(__GNUC__) && defined(__x86_64__)
1575 /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
1576 * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
1577 */
1578 __asm__(".p2align 5");
1579#endif
1580 while (ip < ilimit) {
1581 size_t matchLength=0;
1582 size_t offBase = REPCODE1_TO_OFFBASE;
1583 const BYTE* start=ip+1;
1584 DEBUGLOG(7, "search baseline (depth 0)");
1585
1586 /* check repCode */
1587 if (isDxS) {
1588 const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
1589 const BYTE* repMatch = ((dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch)
1590 && repIndex < prefixLowestIndex) ?
1591 dictBase + (repIndex - dictIndexDelta) :
1592 base + repIndex;
1593 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
1594 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
1595 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
1596 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
1597 if (depth==0) goto _storeSequence;
1598 }
1599 }
1600 if ( dictMode == ZSTD_noDict
1601 && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
1602 matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
1603 if (depth==0) goto _storeSequence;
1604 }
1605
1606 /* first search (depth 0) */
1607 { size_t offbaseFound = 999999999;
1608 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offbaseFound, mls, rowLog, searchMethod, dictMode);
1609 if (ml2 > matchLength)
1610 matchLength = ml2, start = ip, offBase = offbaseFound;
1611 }
1612
1613 if (matchLength < 4) {
1614 size_t const step = ((size_t)(ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */;
1615 ip += step;
1616 /* Enter the lazy skipping mode once we are skipping more than 8 bytes at a time.
1617 * In this mode we stop inserting every position into our tables, and only insert
1618 * positions that we search, which is one in step positions.
1619 * The exact cutoff is flexible, I've just chosen a number that is reasonably high,
1620 * so we minimize the compression ratio loss in "normal" scenarios. This mode gets
1621 * triggered once we've gone 2KB without finding any matches.
1622 */
1623 ms->lazySkipping = step > kLazySkippingStep;
1624 continue;
1625 }
1626
1627 /* let's try to find a better solution */
1628 if (depth>=1)
1629 while (ip<ilimit) {
1630 DEBUGLOG(7, "search depth 1");
1631 ip ++;
1632 if ( (dictMode == ZSTD_noDict)
1633 && (offBase) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
1634 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
1635 int const gain2 = (int)(mlRep * 3);
1636 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offBase) + 1);
1637 if ((mlRep >= 4) && (gain2 > gain1))
1638 matchLength = mlRep, offBase = REPCODE1_TO_OFFBASE, start = ip;
1639 }
1640 if (isDxS) {
1641 const U32 repIndex = (U32)(ip - base) - offset_1;
1642 const BYTE* repMatch = repIndex < prefixLowestIndex ?
1643 dictBase + (repIndex - dictIndexDelta) :
1644 base + repIndex;
1645 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
1646 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
1647 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
1648 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
1649 int const gain2 = (int)(mlRep * 3);
1650 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offBase) + 1);
1651 if ((mlRep >= 4) && (gain2 > gain1))
1652 matchLength = mlRep, offBase = REPCODE1_TO_OFFBASE, start = ip;
1653 }
1654 }
1655 { size_t ofbCandidate=999999999;
1656 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, dictMode);
1657 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */
1658 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 4);
1659 if ((ml2 >= 4) && (gain2 > gain1)) {
1660 matchLength = ml2, offBase = ofbCandidate, start = ip;
1661 continue; /* search a better one */
1662 } }
1663
1664 /* let's find an even better one */
1665 if ((depth==2) && (ip<ilimit)) {
1666 DEBUGLOG(7, "search depth 2");
1667 ip ++;
1668 if ( (dictMode == ZSTD_noDict)
1669 && (offBase) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
1670 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
1671 int const gain2 = (int)(mlRep * 4);
1672 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 1);
1673 if ((mlRep >= 4) && (gain2 > gain1))
1674 matchLength = mlRep, offBase = REPCODE1_TO_OFFBASE, start = ip;
1675 }
1676 if (isDxS) {
1677 const U32 repIndex = (U32)(ip - base) - offset_1;
1678 const BYTE* repMatch = repIndex < prefixLowestIndex ?
1679 dictBase + (repIndex - dictIndexDelta) :
1680 base + repIndex;
1681 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
1682 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
1683 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
1684 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
1685 int const gain2 = (int)(mlRep * 4);
1686 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 1);
1687 if ((mlRep >= 4) && (gain2 > gain1))
1688 matchLength = mlRep, offBase = REPCODE1_TO_OFFBASE, start = ip;
1689 }
1690 }
1691 { size_t ofbCandidate=999999999;
1692 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, dictMode);
1693 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */
1694 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 7);
1695 if ((ml2 >= 4) && (gain2 > gain1)) {
1696 matchLength = ml2, offBase = ofbCandidate, start = ip;
1697 continue;
1698 } } }
1699 break; /* nothing found : store previous solution */
1700 }
1701
1702 /* NOTE:
1703 * Pay attention that `start[-value]` can lead to strange undefined behavior
1704 * notably if `value` is unsigned, resulting in a large positive `-value`.
1705 */
1706 /* catch up */
1707 if (OFFBASE_IS_OFFSET(offBase)) {
1708 if (dictMode == ZSTD_noDict) {
1709 while ( ((start > anchor) & (start - OFFBASE_TO_OFFSET(offBase) > prefixLowest))
1710 && (start[-1] == (start-OFFBASE_TO_OFFSET(offBase))[-1]) ) /* only search for offset within prefix */
1711 { start--; matchLength++; }
1712 }
1713 if (isDxS) {
1714 U32 const matchIndex = (U32)((size_t)(start-base) - OFFBASE_TO_OFFSET(offBase));
1715 const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex;
1716 const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest;
1717 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
1718 }
1719 offset_2 = offset_1; offset_1 = (U32)OFFBASE_TO_OFFSET(offBase);
1720 }
1721 /* store sequence */
1722_storeSequence:
1723 { size_t const litLength = (size_t)(start - anchor);
1724 ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offBase, matchLength);
1725 anchor = ip = start + matchLength;
1726 }
1727 if (ms->lazySkipping) {
1728 /* We've found a match, disable lazy skipping mode, and refill the hash cache. */
1729 if (searchMethod == search_rowHash) {
1730 ZSTD_row_fillHashCache(ms, base, rowLog, mls, ms->nextToUpdate, ilimit);
1731 }
1732 ms->lazySkipping = 0;
1733 }
1734
1735 /* check immediate repcode */
1736 if (isDxS) {
1737 while (ip <= ilimit) {
1738 U32 const current2 = (U32)(ip-base);
1739 U32 const repIndex = current2 - offset_2;
1740 const BYTE* repMatch = repIndex < prefixLowestIndex ?
1741 dictBase - dictIndexDelta + repIndex :
1742 base + repIndex;
1743 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */)
1744 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
1745 const BYTE* const repEnd2 = repIndex < prefixLowestIndex ? dictEnd : iend;
1746 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd2, prefixLowest) + 4;
1747 offBase = offset_2; offset_2 = offset_1; offset_1 = (U32)offBase; /* swap offset_2 <=> offset_1 */
1748 ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, matchLength);
1749 ip += matchLength;
1750 anchor = ip;
1751 continue;
1752 }
1753 break;
1754 }
1755 }
1756
1757 if (dictMode == ZSTD_noDict) {
1758 while ( ((ip <= ilimit) & (offset_2>0))
1759 && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
1760 /* store sequence */
1761 matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
1762 offBase = offset_2; offset_2 = offset_1; offset_1 = (U32)offBase; /* swap repcodes */
1763 ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, matchLength);
1764 ip += matchLength;
1765 anchor = ip;
1766 continue; /* faster when present ... (?) */
1767 } } }
1768
1769 /* If offset_1 started invalid (offsetSaved1 != 0) and became valid (offset_1 != 0),
1770 * rotate saved offsets. See comment in ZSTD_compressBlock_fast_noDict for more context. */
1771 offsetSaved2 = ((offsetSaved1 != 0) && (offset_1 != 0)) ? offsetSaved1 : offsetSaved2;
1772
1773 /* save reps for next block */
1774 rep[0] = offset_1 ? offset_1 : offsetSaved1;
1775 rep[1] = offset_2 ? offset_2 : offsetSaved2;
1776
1777 /* Return the last literals size */
1778 return (size_t)(iend - anchor);
1779}
f535537f 1780#endif /* build exclusions */
648db22b 1781
1782
f535537f 1783#ifndef ZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR
1784size_t ZSTD_compressBlock_greedy(
648db22b 1785 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1786 void const* src, size_t srcSize)
1787{
f535537f 1788 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_noDict);
648db22b 1789}
1790
f535537f 1791size_t ZSTD_compressBlock_greedy_dictMatchState(
648db22b 1792 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1793 void const* src, size_t srcSize)
1794{
f535537f 1795 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dictMatchState);
648db22b 1796}
1797
f535537f 1798size_t ZSTD_compressBlock_greedy_dedicatedDictSearch(
648db22b 1799 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1800 void const* src, size_t srcSize)
1801{
f535537f 1802 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dedicatedDictSearch);
648db22b 1803}
1804
f535537f 1805size_t ZSTD_compressBlock_greedy_row(
648db22b 1806 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1807 void const* src, size_t srcSize)
1808{
f535537f 1809 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0, ZSTD_noDict);
648db22b 1810}
1811
f535537f 1812size_t ZSTD_compressBlock_greedy_dictMatchState_row(
648db22b 1813 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1814 void const* src, size_t srcSize)
1815{
f535537f 1816 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0, ZSTD_dictMatchState);
648db22b 1817}
1818
f535537f 1819size_t ZSTD_compressBlock_greedy_dedicatedDictSearch_row(
648db22b 1820 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1821 void const* src, size_t srcSize)
1822{
f535537f 1823 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0, ZSTD_dedicatedDictSearch);
648db22b 1824}
f535537f 1825#endif
648db22b 1826
f535537f 1827#ifndef ZSTD_EXCLUDE_LAZY_BLOCK_COMPRESSOR
1828size_t ZSTD_compressBlock_lazy(
648db22b 1829 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1830 void const* src, size_t srcSize)
1831{
f535537f 1832 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_noDict);
648db22b 1833}
1834
f535537f 1835size_t ZSTD_compressBlock_lazy_dictMatchState(
648db22b 1836 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1837 void const* src, size_t srcSize)
1838{
f535537f 1839 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dictMatchState);
648db22b 1840}
1841
f535537f 1842size_t ZSTD_compressBlock_lazy_dedicatedDictSearch(
648db22b 1843 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1844 void const* src, size_t srcSize)
1845{
f535537f 1846 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dedicatedDictSearch);
648db22b 1847}
1848
f535537f 1849size_t ZSTD_compressBlock_lazy_row(
648db22b 1850 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1851 void const* src, size_t srcSize)
1852{
f535537f 1853 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1, ZSTD_noDict);
648db22b 1854}
1855
f535537f 1856size_t ZSTD_compressBlock_lazy_dictMatchState_row(
648db22b 1857 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1858 void const* src, size_t srcSize)
1859{
f535537f 1860 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1, ZSTD_dictMatchState);
648db22b 1861}
1862
f535537f 1863size_t ZSTD_compressBlock_lazy_dedicatedDictSearch_row(
648db22b 1864 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1865 void const* src, size_t srcSize)
1866{
f535537f 1867 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1, ZSTD_dedicatedDictSearch);
648db22b 1868}
f535537f 1869#endif
648db22b 1870
f535537f 1871#ifndef ZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR
1872size_t ZSTD_compressBlock_lazy2(
648db22b 1873 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1874 void const* src, size_t srcSize)
1875{
f535537f 1876 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_noDict);
648db22b 1877}
1878
f535537f 1879size_t ZSTD_compressBlock_lazy2_dictMatchState(
648db22b 1880 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1881 void const* src, size_t srcSize)
1882{
f535537f 1883 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dictMatchState);
648db22b 1884}
1885
f535537f 1886size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch(
648db22b 1887 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1888 void const* src, size_t srcSize)
1889{
f535537f 1890 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dedicatedDictSearch);
648db22b 1891}
1892
f535537f 1893size_t ZSTD_compressBlock_lazy2_row(
648db22b 1894 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1895 void const* src, size_t srcSize)
1896{
f535537f 1897 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2, ZSTD_noDict);
648db22b 1898}
1899
f535537f 1900size_t ZSTD_compressBlock_lazy2_dictMatchState_row(
648db22b 1901 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1902 void const* src, size_t srcSize)
1903{
f535537f 1904 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2, ZSTD_dictMatchState);
648db22b 1905}
1906
648db22b 1907size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch_row(
1908 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1909 void const* src, size_t srcSize)
1910{
1911 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2, ZSTD_dedicatedDictSearch);
1912}
f535537f 1913#endif
648db22b 1914
f535537f 1915#ifndef ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR
1916size_t ZSTD_compressBlock_btlazy2(
648db22b 1917 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1918 void const* src, size_t srcSize)
1919{
f535537f 1920 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_noDict);
648db22b 1921}
1922
f535537f 1923size_t ZSTD_compressBlock_btlazy2_dictMatchState(
648db22b 1924 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
1925 void const* src, size_t srcSize)
1926{
f535537f 1927 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_dictMatchState);
648db22b 1928}
f535537f 1929#endif
648db22b 1930
f535537f 1931#if !defined(ZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR) \
1932 || !defined(ZSTD_EXCLUDE_LAZY_BLOCK_COMPRESSOR) \
1933 || !defined(ZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR) \
1934 || !defined(ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR)
648db22b 1935FORCE_INLINE_TEMPLATE
f535537f 1936ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
648db22b 1937size_t ZSTD_compressBlock_lazy_extDict_generic(
1938 ZSTD_matchState_t* ms, seqStore_t* seqStore,
1939 U32 rep[ZSTD_REP_NUM],
1940 const void* src, size_t srcSize,
1941 const searchMethod_e searchMethod, const U32 depth)
1942{
1943 const BYTE* const istart = (const BYTE*)src;
1944 const BYTE* ip = istart;
1945 const BYTE* anchor = istart;
1946 const BYTE* const iend = istart + srcSize;
1947 const BYTE* const ilimit = searchMethod == search_rowHash ? iend - 8 - ZSTD_ROW_HASH_CACHE_SIZE : iend - 8;
1948 const BYTE* const base = ms->window.base;
1949 const U32 dictLimit = ms->window.dictLimit;
1950 const BYTE* const prefixStart = base + dictLimit;
1951 const BYTE* const dictBase = ms->window.dictBase;
1952 const BYTE* const dictEnd = dictBase + dictLimit;
1953 const BYTE* const dictStart = dictBase + ms->window.lowLimit;
1954 const U32 windowLog = ms->cParams.windowLog;
1955 const U32 mls = BOUNDED(4, ms->cParams.minMatch, 6);
1956 const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
1957
1958 U32 offset_1 = rep[0], offset_2 = rep[1];
1959
1960 DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic (searchFunc=%u)", (U32)searchMethod);
1961
1962 /* Reset the lazy skipping state */
1963 ms->lazySkipping = 0;
1964
1965 /* init */
1966 ip += (ip == prefixStart);
1967 if (searchMethod == search_rowHash) {
1968 ZSTD_row_fillHashCache(ms, base, rowLog, mls, ms->nextToUpdate, ilimit);
1969 }
1970
1971 /* Match Loop */
1972#if defined(__GNUC__) && defined(__x86_64__)
1973 /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
1974 * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
1975 */
1976 __asm__(".p2align 5");
1977#endif
1978 while (ip < ilimit) {
1979 size_t matchLength=0;
1980 size_t offBase = REPCODE1_TO_OFFBASE;
1981 const BYTE* start=ip+1;
1982 U32 curr = (U32)(ip-base);
1983
1984 /* check repCode */
1985 { const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr+1, windowLog);
1986 const U32 repIndex = (U32)(curr+1 - offset_1);
1987 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
1988 const BYTE* const repMatch = repBase + repIndex;
1989 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
1990 & (offset_1 <= curr+1 - windowLow) ) /* note: we are searching at curr+1 */
1991 if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
1992 /* repcode detected we should take it */
1993 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
1994 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4;
1995 if (depth==0) goto _storeSequence;
1996 } }
1997
1998 /* first search (depth 0) */
1999 { size_t ofbCandidate = 999999999;
2000 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, ZSTD_extDict);
2001 if (ml2 > matchLength)
2002 matchLength = ml2, start = ip, offBase = ofbCandidate;
2003 }
2004
2005 if (matchLength < 4) {
2006 size_t const step = ((size_t)(ip-anchor) >> kSearchStrength);
2007 ip += step + 1; /* jump faster over incompressible sections */
2008 /* Enter the lazy skipping mode once we are skipping more than 8 bytes at a time.
2009 * In this mode we stop inserting every position into our tables, and only insert
2010 * positions that we search, which is one in step positions.
2011 * The exact cutoff is flexible, I've just chosen a number that is reasonably high,
2012 * so we minimize the compression ratio loss in "normal" scenarios. This mode gets
2013 * triggered once we've gone 2KB without finding any matches.
2014 */
2015 ms->lazySkipping = step > kLazySkippingStep;
2016 continue;
2017 }
2018
2019 /* let's try to find a better solution */
2020 if (depth>=1)
2021 while (ip<ilimit) {
2022 ip ++;
2023 curr++;
2024 /* check repCode */
2025 if (offBase) {
2026 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog);
2027 const U32 repIndex = (U32)(curr - offset_1);
2028 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
2029 const BYTE* const repMatch = repBase + repIndex;
2030 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
2031 & (offset_1 <= curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
2032 if (MEM_read32(ip) == MEM_read32(repMatch)) {
2033 /* repcode detected */
2034 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
2035 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
2036 int const gain2 = (int)(repLength * 3);
2037 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offBase) + 1);
2038 if ((repLength >= 4) && (gain2 > gain1))
2039 matchLength = repLength, offBase = REPCODE1_TO_OFFBASE, start = ip;
2040 } }
2041
2042 /* search match, depth 1 */
2043 { size_t ofbCandidate = 999999999;
2044 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, ZSTD_extDict);
2045 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */
2046 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 4);
2047 if ((ml2 >= 4) && (gain2 > gain1)) {
2048 matchLength = ml2, offBase = ofbCandidate, start = ip;
2049 continue; /* search a better one */
2050 } }
2051
2052 /* let's find an even better one */
2053 if ((depth==2) && (ip<ilimit)) {
2054 ip ++;
2055 curr++;
2056 /* check repCode */
2057 if (offBase) {
2058 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog);
2059 const U32 repIndex = (U32)(curr - offset_1);
2060 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
2061 const BYTE* const repMatch = repBase + repIndex;
2062 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
2063 & (offset_1 <= curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
2064 if (MEM_read32(ip) == MEM_read32(repMatch)) {
2065 /* repcode detected */
2066 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
2067 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
2068 int const gain2 = (int)(repLength * 4);
2069 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 1);
2070 if ((repLength >= 4) && (gain2 > gain1))
2071 matchLength = repLength, offBase = REPCODE1_TO_OFFBASE, start = ip;
2072 } }
2073
2074 /* search match, depth 2 */
2075 { size_t ofbCandidate = 999999999;
2076 size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, ZSTD_extDict);
2077 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */
2078 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 7);
2079 if ((ml2 >= 4) && (gain2 > gain1)) {
2080 matchLength = ml2, offBase = ofbCandidate, start = ip;
2081 continue;
2082 } } }
2083 break; /* nothing found : store previous solution */
2084 }
2085
2086 /* catch up */
2087 if (OFFBASE_IS_OFFSET(offBase)) {
2088 U32 const matchIndex = (U32)((size_t)(start-base) - OFFBASE_TO_OFFSET(offBase));
2089 const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
2090 const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
2091 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
2092 offset_2 = offset_1; offset_1 = (U32)OFFBASE_TO_OFFSET(offBase);
2093 }
2094
2095 /* store sequence */
2096_storeSequence:
2097 { size_t const litLength = (size_t)(start - anchor);
2098 ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offBase, matchLength);
2099 anchor = ip = start + matchLength;
2100 }
2101 if (ms->lazySkipping) {
2102 /* We've found a match, disable lazy skipping mode, and refill the hash cache. */
2103 if (searchMethod == search_rowHash) {
2104 ZSTD_row_fillHashCache(ms, base, rowLog, mls, ms->nextToUpdate, ilimit);
2105 }
2106 ms->lazySkipping = 0;
2107 }
2108
2109 /* check immediate repcode */
2110 while (ip <= ilimit) {
2111 const U32 repCurrent = (U32)(ip-base);
2112 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, repCurrent, windowLog);
2113 const U32 repIndex = repCurrent - offset_2;
2114 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
2115 const BYTE* const repMatch = repBase + repIndex;
2116 if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
2117 & (offset_2 <= repCurrent - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
2118 if (MEM_read32(ip) == MEM_read32(repMatch)) {
2119 /* repcode detected we should take it */
2120 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
2121 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
2122 offBase = offset_2; offset_2 = offset_1; offset_1 = (U32)offBase; /* swap offset history */
2123 ZSTD_storeSeq(seqStore, 0, anchor, iend, REPCODE1_TO_OFFBASE, matchLength);
2124 ip += matchLength;
2125 anchor = ip;
2126 continue; /* faster when present ... (?) */
2127 }
2128 break;
2129 } }
2130
2131 /* Save reps for next block */
2132 rep[0] = offset_1;
2133 rep[1] = offset_2;
2134
2135 /* Return the last literals size */
2136 return (size_t)(iend - anchor);
2137}
f535537f 2138#endif /* build exclusions */
648db22b 2139
f535537f 2140#ifndef ZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR
648db22b 2141size_t ZSTD_compressBlock_greedy_extDict(
2142 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2143 void const* src, size_t srcSize)
2144{
2145 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0);
2146}
2147
f535537f 2148size_t ZSTD_compressBlock_greedy_extDict_row(
648db22b 2149 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2150 void const* src, size_t srcSize)
648db22b 2151{
f535537f 2152 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 0);
648db22b 2153}
f535537f 2154#endif
648db22b 2155
f535537f 2156#ifndef ZSTD_EXCLUDE_LAZY_BLOCK_COMPRESSOR
2157size_t ZSTD_compressBlock_lazy_extDict(
648db22b 2158 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2159 void const* src, size_t srcSize)
2160
2161{
f535537f 2162 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1);
648db22b 2163}
2164
f535537f 2165size_t ZSTD_compressBlock_lazy_extDict_row(
648db22b 2166 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2167 void const* src, size_t srcSize)
2168
2169{
f535537f 2170 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 1);
648db22b 2171}
f535537f 2172#endif
648db22b 2173
f535537f 2174#ifndef ZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR
2175size_t ZSTD_compressBlock_lazy2_extDict(
648db22b 2176 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2177 void const* src, size_t srcSize)
f535537f 2178
648db22b 2179{
f535537f 2180 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2);
648db22b 2181}
2182
f535537f 2183size_t ZSTD_compressBlock_lazy2_extDict_row(
648db22b 2184 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2185 void const* src, size_t srcSize)
648db22b 2186{
f535537f 2187 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_rowHash, 2);
648db22b 2188}
f535537f 2189#endif
648db22b 2190
f535537f 2191#ifndef ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR
2192size_t ZSTD_compressBlock_btlazy2_extDict(
648db22b 2193 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
2194 void const* src, size_t srcSize)
f535537f 2195
648db22b 2196{
f535537f 2197 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2);
648db22b 2198}
f535537f 2199#endif
ARM optimized PCSX fork