blob: 94d906c01f1c801db7776f1f25857dcdfd0056b6 [file] [log] [blame]
William Kurkianea869482019-04-09 15:16:11 -04001/*
2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11#include "zstd_compress_internal.h"
12#include "zstd_lazy.h"
13
14
15/*-*************************************
16* Binary Tree search
17***************************************/
18
Abhilash S.L3b494632019-07-16 15:51:09 +053019static void
20ZSTD_updateDUBT(ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -040021 const BYTE* ip, const BYTE* iend,
22 U32 mls)
23{
Abhilash S.L3b494632019-07-16 15:51:09 +053024 const ZSTD_compressionParameters* const cParams = &ms->cParams;
William Kurkianea869482019-04-09 15:16:11 -040025 U32* const hashTable = ms->hashTable;
26 U32 const hashLog = cParams->hashLog;
27
28 U32* const bt = ms->chainTable;
29 U32 const btLog = cParams->chainLog - 1;
30 U32 const btMask = (1 << btLog) - 1;
31
32 const BYTE* const base = ms->window.base;
33 U32 const target = (U32)(ip - base);
34 U32 idx = ms->nextToUpdate;
35
36 if (idx != target)
37 DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)",
38 idx, target, ms->window.dictLimit);
39 assert(ip + 8 <= iend); /* condition for ZSTD_hashPtr */
40 (void)iend;
41
42 assert(idx >= ms->window.dictLimit); /* condition for valid base+idx */
43 for ( ; idx < target ; idx++) {
44 size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls); /* assumption : ip + 8 <= iend */
45 U32 const matchIndex = hashTable[h];
46
47 U32* const nextCandidatePtr = bt + 2*(idx&btMask);
48 U32* const sortMarkPtr = nextCandidatePtr + 1;
49
50 DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx);
51 hashTable[h] = idx; /* Update Hash Table */
52 *nextCandidatePtr = matchIndex; /* update BT like a chain */
53 *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK;
54 }
55 ms->nextToUpdate = target;
56}
57
58
59/** ZSTD_insertDUBT1() :
60 * sort one already inserted but unsorted position
61 * assumption : current >= btlow == (current - btmask)
62 * doesn't fail */
Abhilash S.L3b494632019-07-16 15:51:09 +053063static void
64ZSTD_insertDUBT1(ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -040065 U32 current, const BYTE* inputEnd,
Abhilash S.L3b494632019-07-16 15:51:09 +053066 U32 nbCompares, U32 btLow,
67 const ZSTD_dictMode_e dictMode)
William Kurkianea869482019-04-09 15:16:11 -040068{
Abhilash S.L3b494632019-07-16 15:51:09 +053069 const ZSTD_compressionParameters* const cParams = &ms->cParams;
70 U32* const bt = ms->chainTable;
71 U32 const btLog = cParams->chainLog - 1;
72 U32 const btMask = (1 << btLog) - 1;
William Kurkianea869482019-04-09 15:16:11 -040073 size_t commonLengthSmaller=0, commonLengthLarger=0;
74 const BYTE* const base = ms->window.base;
75 const BYTE* const dictBase = ms->window.dictBase;
76 const U32 dictLimit = ms->window.dictLimit;
77 const BYTE* const ip = (current>=dictLimit) ? base + current : dictBase + current;
78 const BYTE* const iend = (current>=dictLimit) ? inputEnd : dictBase + dictLimit;
79 const BYTE* const dictEnd = dictBase + dictLimit;
80 const BYTE* const prefixStart = base + dictLimit;
81 const BYTE* match;
82 U32* smallerPtr = bt + 2*(current&btMask);
83 U32* largerPtr = smallerPtr + 1;
Abhilash S.L3b494632019-07-16 15:51:09 +053084 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) */
William Kurkianea869482019-04-09 15:16:11 -040085 U32 dummy32; /* to be nullified at the end */
Devmalya Pauleb2e9552019-08-27 19:42:00 -040086 U32 const windowValid = ms->window.lowLimit;
87 U32 const maxDistance = 1U << cParams->windowLog;
88 U32 const windowLow = (current - windowValid > maxDistance) ? current - maxDistance : windowValid;
89
William Kurkianea869482019-04-09 15:16:11 -040090
91 DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
92 current, dictLimit, windowLow);
93 assert(current >= btLow);
94 assert(ip < iend); /* condition for ZSTD_count */
95
96 while (nbCompares-- && (matchIndex > windowLow)) {
97 U32* const nextPtr = bt + 2*(matchIndex & btMask);
98 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
99 assert(matchIndex < current);
Abhilash S.L3b494632019-07-16 15:51:09 +0530100 /* note : all candidates are now supposed sorted,
101 * but it's still possible to have nextPtr[1] == ZSTD_DUBT_UNSORTED_MARK
102 * when a real index has the same value as ZSTD_DUBT_UNSORTED_MARK */
William Kurkianea869482019-04-09 15:16:11 -0400103
Abhilash S.L3b494632019-07-16 15:51:09 +0530104 if ( (dictMode != ZSTD_extDict)
William Kurkianea869482019-04-09 15:16:11 -0400105 || (matchIndex+matchLength >= dictLimit) /* both in current segment*/
106 || (current < dictLimit) /* both in extDict */) {
Abhilash S.L3b494632019-07-16 15:51:09 +0530107 const BYTE* const mBase = ( (dictMode != ZSTD_extDict)
108 || (matchIndex+matchLength >= dictLimit)) ?
109 base : dictBase;
William Kurkianea869482019-04-09 15:16:11 -0400110 assert( (matchIndex+matchLength >= dictLimit) /* might be wrong if extDict is incorrectly set to 0 */
111 || (current < dictLimit) );
112 match = mBase + matchIndex;
113 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
114 } else {
115 match = dictBase + matchIndex;
116 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
117 if (matchIndex+matchLength >= dictLimit)
Abhilash S.L3b494632019-07-16 15:51:09 +0530118 match = base + matchIndex; /* preparation for next read of match[matchLength] */
William Kurkianea869482019-04-09 15:16:11 -0400119 }
120
121 DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ",
122 current, matchIndex, (U32)matchLength);
123
124 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
125 break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
126 }
127
128 if (match[matchLength] < ip[matchLength]) { /* necessarily within buffer */
129 /* match is smaller than current */
130 *smallerPtr = matchIndex; /* update smaller idx */
131 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
132 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop searching */
133 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u",
134 matchIndex, btLow, nextPtr[1]);
135 smallerPtr = nextPtr+1; /* new "candidate" => larger than match, which was smaller than target */
136 matchIndex = nextPtr[1]; /* new matchIndex, larger than previous and closer to current */
137 } else {
138 /* match is larger than current */
139 *largerPtr = matchIndex;
140 commonLengthLarger = matchLength;
141 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop searching */
142 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u",
143 matchIndex, btLow, nextPtr[0]);
144 largerPtr = nextPtr;
145 matchIndex = nextPtr[0];
146 } }
147
148 *smallerPtr = *largerPtr = 0;
149}
150
151
Abhilash S.L3b494632019-07-16 15:51:09 +0530152static size_t
153ZSTD_DUBT_findBetterDictMatch (
154 ZSTD_matchState_t* ms,
155 const BYTE* const ip, const BYTE* const iend,
156 size_t* offsetPtr,
157 size_t bestLength,
158 U32 nbCompares,
159 U32 const mls,
160 const ZSTD_dictMode_e dictMode)
William Kurkianea869482019-04-09 15:16:11 -0400161{
Abhilash S.L3b494632019-07-16 15:51:09 +0530162 const ZSTD_matchState_t * const dms = ms->dictMatchState;
163 const ZSTD_compressionParameters* const dmsCParams = &dms->cParams;
164 const U32 * const dictHashTable = dms->hashTable;
165 U32 const hashLog = dmsCParams->hashLog;
166 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
167 U32 dictMatchIndex = dictHashTable[h];
168
169 const BYTE* const base = ms->window.base;
170 const BYTE* const prefixStart = base + ms->window.dictLimit;
171 U32 const current = (U32)(ip-base);
172 const BYTE* const dictBase = dms->window.base;
173 const BYTE* const dictEnd = dms->window.nextSrc;
174 U32 const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base);
175 U32 const dictLowLimit = dms->window.lowLimit;
176 U32 const dictIndexDelta = ms->window.lowLimit - dictHighLimit;
177
178 U32* const dictBt = dms->chainTable;
179 U32 const btLog = dmsCParams->chainLog - 1;
180 U32 const btMask = (1 << btLog) - 1;
181 U32 const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask;
182
183 size_t commonLengthSmaller=0, commonLengthLarger=0;
184
185 (void)dictMode;
186 assert(dictMode == ZSTD_dictMatchState);
187
188 while (nbCompares-- && (dictMatchIndex > dictLowLimit)) {
189 U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask);
190 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
191 const BYTE* match = dictBase + dictMatchIndex;
192 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
193 if (dictMatchIndex+matchLength >= dictHighLimit)
194 match = base + dictMatchIndex + dictIndexDelta; /* to prepare for next usage of match[matchLength] */
195
196 if (matchLength > bestLength) {
197 U32 matchIndex = dictMatchIndex + dictIndexDelta;
198 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) {
199 DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)",
200 current, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, ZSTD_REP_MOVE + current - matchIndex, dictMatchIndex, matchIndex);
201 bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
202 }
203 if (ip+matchLength == iend) { /* reached end of input : ip[matchLength] is not valid, no way to know if it's larger or smaller than match */
204 break; /* drop, to guarantee consistency (miss a little bit of compression) */
205 }
206 }
207
208 if (match[matchLength] < ip[matchLength]) {
209 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */
210 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
211 dictMatchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
212 } else {
213 /* match is larger than current */
214 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */
215 commonLengthLarger = matchLength;
216 dictMatchIndex = nextPtr[0];
217 }
218 }
219
220 if (bestLength >= MINMATCH) {
221 U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
222 DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
223 current, (U32)bestLength, (U32)*offsetPtr, mIndex);
224 }
225 return bestLength;
226
227}
228
229
230static size_t
231ZSTD_DUBT_findBestMatch(ZSTD_matchState_t* ms,
232 const BYTE* const ip, const BYTE* const iend,
233 size_t* offsetPtr,
234 U32 const mls,
235 const ZSTD_dictMode_e dictMode)
236{
237 const ZSTD_compressionParameters* const cParams = &ms->cParams;
William Kurkianea869482019-04-09 15:16:11 -0400238 U32* const hashTable = ms->hashTable;
239 U32 const hashLog = cParams->hashLog;
240 size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
241 U32 matchIndex = hashTable[h];
242
243 const BYTE* const base = ms->window.base;
244 U32 const current = (U32)(ip-base);
Devmalya Pauleb2e9552019-08-27 19:42:00 -0400245 U32 const maxDistance = 1U << cParams->windowLog;
246 U32 const windowValid = ms->window.lowLimit;
247 U32 const windowLow = (current - windowValid > maxDistance) ? current - maxDistance : windowValid;
William Kurkianea869482019-04-09 15:16:11 -0400248
249 U32* const bt = ms->chainTable;
250 U32 const btLog = cParams->chainLog - 1;
251 U32 const btMask = (1 << btLog) - 1;
252 U32 const btLow = (btMask >= current) ? 0 : current - btMask;
253 U32 const unsortLimit = MAX(btLow, windowLow);
254
255 U32* nextCandidate = bt + 2*(matchIndex&btMask);
256 U32* unsortedMark = bt + 2*(matchIndex&btMask) + 1;
257 U32 nbCompares = 1U << cParams->searchLog;
258 U32 nbCandidates = nbCompares;
259 U32 previousCandidate = 0;
260
261 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", current);
262 assert(ip <= iend-8); /* required for h calculation */
263
264 /* reach end of unsorted candidates list */
265 while ( (matchIndex > unsortLimit)
266 && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK)
267 && (nbCandidates > 1) ) {
268 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted",
269 matchIndex);
Abhilash S.L3b494632019-07-16 15:51:09 +0530270 *unsortedMark = previousCandidate; /* the unsortedMark becomes a reversed chain, to move up back to original position */
William Kurkianea869482019-04-09 15:16:11 -0400271 previousCandidate = matchIndex;
272 matchIndex = *nextCandidate;
273 nextCandidate = bt + 2*(matchIndex&btMask);
274 unsortedMark = bt + 2*(matchIndex&btMask) + 1;
275 nbCandidates --;
276 }
277
Abhilash S.L3b494632019-07-16 15:51:09 +0530278 /* nullify last candidate if it's still unsorted
279 * simplification, detrimental to compression ratio, beneficial for speed */
William Kurkianea869482019-04-09 15:16:11 -0400280 if ( (matchIndex > unsortLimit)
281 && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) {
282 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u",
283 matchIndex);
Abhilash S.L3b494632019-07-16 15:51:09 +0530284 *nextCandidate = *unsortedMark = 0;
William Kurkianea869482019-04-09 15:16:11 -0400285 }
286
287 /* batch sort stacked candidates */
288 matchIndex = previousCandidate;
289 while (matchIndex) { /* will end on matchIndex == 0 */
290 U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1;
291 U32 const nextCandidateIdx = *nextCandidateIdxPtr;
Abhilash S.L3b494632019-07-16 15:51:09 +0530292 ZSTD_insertDUBT1(ms, matchIndex, iend,
293 nbCandidates, unsortLimit, dictMode);
William Kurkianea869482019-04-09 15:16:11 -0400294 matchIndex = nextCandidateIdx;
295 nbCandidates++;
296 }
297
298 /* find longest match */
Abhilash S.L3b494632019-07-16 15:51:09 +0530299 { size_t commonLengthSmaller = 0, commonLengthLarger = 0;
William Kurkianea869482019-04-09 15:16:11 -0400300 const BYTE* const dictBase = ms->window.dictBase;
301 const U32 dictLimit = ms->window.dictLimit;
302 const BYTE* const dictEnd = dictBase + dictLimit;
303 const BYTE* const prefixStart = base + dictLimit;
304 U32* smallerPtr = bt + 2*(current&btMask);
305 U32* largerPtr = bt + 2*(current&btMask) + 1;
Abhilash S.L3b494632019-07-16 15:51:09 +0530306 U32 matchEndIdx = current + 8 + 1;
William Kurkianea869482019-04-09 15:16:11 -0400307 U32 dummy32; /* to be nullified at the end */
308 size_t bestLength = 0;
309
310 matchIndex = hashTable[h];
311 hashTable[h] = current; /* Update Hash Table */
312
313 while (nbCompares-- && (matchIndex > windowLow)) {
314 U32* const nextPtr = bt + 2*(matchIndex & btMask);
315 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
316 const BYTE* match;
317
Abhilash S.L3b494632019-07-16 15:51:09 +0530318 if ((dictMode != ZSTD_extDict) || (matchIndex+matchLength >= dictLimit)) {
William Kurkianea869482019-04-09 15:16:11 -0400319 match = base + matchIndex;
320 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
321 } else {
322 match = dictBase + matchIndex;
323 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
324 if (matchIndex+matchLength >= dictLimit)
325 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
326 }
327
328 if (matchLength > bestLength) {
329 if (matchLength > matchEndIdx - matchIndex)
330 matchEndIdx = matchIndex + (U32)matchLength;
331 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
332 bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
333 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */
Abhilash S.L3b494632019-07-16 15:51:09 +0530334 if (dictMode == ZSTD_dictMatchState) {
335 nbCompares = 0; /* in addition to avoiding checking any
336 * further in this loop, make sure we
337 * skip checking in the dictionary. */
338 }
William Kurkianea869482019-04-09 15:16:11 -0400339 break; /* drop, to guarantee consistency (miss a little bit of compression) */
340 }
341 }
342
343 if (match[matchLength] < ip[matchLength]) {
344 /* match is smaller than current */
345 *smallerPtr = matchIndex; /* update smaller idx */
346 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
347 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
348 smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
349 matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
350 } else {
351 /* match is larger than current */
352 *largerPtr = matchIndex;
353 commonLengthLarger = matchLength;
354 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
355 largerPtr = nextPtr;
356 matchIndex = nextPtr[0];
357 } }
358
359 *smallerPtr = *largerPtr = 0;
360
Abhilash S.L3b494632019-07-16 15:51:09 +0530361 if (dictMode == ZSTD_dictMatchState && nbCompares) {
362 bestLength = ZSTD_DUBT_findBetterDictMatch(
363 ms, ip, iend,
364 offsetPtr, bestLength, nbCompares,
365 mls, dictMode);
366 }
367
William Kurkianea869482019-04-09 15:16:11 -0400368 assert(matchEndIdx > current+8); /* ensure nextToUpdate is increased */
369 ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */
370 if (bestLength >= MINMATCH) {
371 U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
372 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
373 current, (U32)bestLength, (U32)*offsetPtr, mIndex);
374 }
375 return bestLength;
376 }
377}
378
379
380/** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
Abhilash S.L3b494632019-07-16 15:51:09 +0530381FORCE_INLINE_TEMPLATE size_t
382ZSTD_BtFindBestMatch( ZSTD_matchState_t* ms,
383 const BYTE* const ip, const BYTE* const iLimit,
384 size_t* offsetPtr,
385 const U32 mls /* template */,
386 const ZSTD_dictMode_e dictMode)
William Kurkianea869482019-04-09 15:16:11 -0400387{
388 DEBUGLOG(7, "ZSTD_BtFindBestMatch");
389 if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */
Abhilash S.L3b494632019-07-16 15:51:09 +0530390 ZSTD_updateDUBT(ms, ip, iLimit, mls);
391 return ZSTD_DUBT_findBestMatch(ms, ip, iLimit, offsetPtr, mls, dictMode);
William Kurkianea869482019-04-09 15:16:11 -0400392}
393
394
Abhilash S.L3b494632019-07-16 15:51:09 +0530395static size_t
396ZSTD_BtFindBestMatch_selectMLS ( ZSTD_matchState_t* ms,
397 const BYTE* ip, const BYTE* const iLimit,
398 size_t* offsetPtr)
William Kurkianea869482019-04-09 15:16:11 -0400399{
Abhilash S.L3b494632019-07-16 15:51:09 +0530400 switch(ms->cParams.minMatch)
William Kurkianea869482019-04-09 15:16:11 -0400401 {
402 default : /* includes case 3 */
Abhilash S.L3b494632019-07-16 15:51:09 +0530403 case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict);
404 case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict);
William Kurkianea869482019-04-09 15:16:11 -0400405 case 7 :
Abhilash S.L3b494632019-07-16 15:51:09 +0530406 case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict);
William Kurkianea869482019-04-09 15:16:11 -0400407 }
408}
409
410
Abhilash S.L3b494632019-07-16 15:51:09 +0530411static size_t ZSTD_BtFindBestMatch_dictMatchState_selectMLS (
412 ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -0400413 const BYTE* ip, const BYTE* const iLimit,
414 size_t* offsetPtr)
415{
Abhilash S.L3b494632019-07-16 15:51:09 +0530416 switch(ms->cParams.minMatch)
William Kurkianea869482019-04-09 15:16:11 -0400417 {
418 default : /* includes case 3 */
Abhilash S.L3b494632019-07-16 15:51:09 +0530419 case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState);
420 case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState);
William Kurkianea869482019-04-09 15:16:11 -0400421 case 7 :
Abhilash S.L3b494632019-07-16 15:51:09 +0530422 case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState);
423 }
424}
425
426
427static size_t ZSTD_BtFindBestMatch_extDict_selectMLS (
428 ZSTD_matchState_t* ms,
429 const BYTE* ip, const BYTE* const iLimit,
430 size_t* offsetPtr)
431{
432 switch(ms->cParams.minMatch)
433 {
434 default : /* includes case 3 */
435 case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict);
436 case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict);
437 case 7 :
438 case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict);
William Kurkianea869482019-04-09 15:16:11 -0400439 }
440}
441
442
443
444/* *********************************
445* Hash Chain
446***********************************/
Abhilash S.L3b494632019-07-16 15:51:09 +0530447#define NEXT_IN_CHAIN(d, mask) chainTable[(d) & (mask)]
William Kurkianea869482019-04-09 15:16:11 -0400448
449/* Update chains up to ip (excluded)
450 Assumption : always within prefix (i.e. not within extDict) */
451static U32 ZSTD_insertAndFindFirstIndex_internal(
Abhilash S.L3b494632019-07-16 15:51:09 +0530452 ZSTD_matchState_t* ms,
453 const ZSTD_compressionParameters* const cParams,
William Kurkianea869482019-04-09 15:16:11 -0400454 const BYTE* ip, U32 const mls)
455{
456 U32* const hashTable = ms->hashTable;
457 const U32 hashLog = cParams->hashLog;
458 U32* const chainTable = ms->chainTable;
459 const U32 chainMask = (1 << cParams->chainLog) - 1;
460 const BYTE* const base = ms->window.base;
461 const U32 target = (U32)(ip - base);
462 U32 idx = ms->nextToUpdate;
463
464 while(idx < target) { /* catch up */
465 size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
466 NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
467 hashTable[h] = idx;
468 idx++;
469 }
470
471 ms->nextToUpdate = target;
472 return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
473}
474
Abhilash S.L3b494632019-07-16 15:51:09 +0530475U32 ZSTD_insertAndFindFirstIndex(ZSTD_matchState_t* ms, const BYTE* ip) {
476 const ZSTD_compressionParameters* const cParams = &ms->cParams;
477 return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, ms->cParams.minMatch);
William Kurkianea869482019-04-09 15:16:11 -0400478}
479
480
481/* inlining is important to hardwire a hot branch (template emulation) */
482FORCE_INLINE_TEMPLATE
483size_t ZSTD_HcFindBestMatch_generic (
Abhilash S.L3b494632019-07-16 15:51:09 +0530484 ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -0400485 const BYTE* const ip, const BYTE* const iLimit,
486 size_t* offsetPtr,
Abhilash S.L3b494632019-07-16 15:51:09 +0530487 const U32 mls, const ZSTD_dictMode_e dictMode)
William Kurkianea869482019-04-09 15:16:11 -0400488{
Abhilash S.L3b494632019-07-16 15:51:09 +0530489 const ZSTD_compressionParameters* const cParams = &ms->cParams;
William Kurkianea869482019-04-09 15:16:11 -0400490 U32* const chainTable = ms->chainTable;
491 const U32 chainSize = (1 << cParams->chainLog);
492 const U32 chainMask = chainSize-1;
493 const BYTE* const base = ms->window.base;
494 const BYTE* const dictBase = ms->window.dictBase;
495 const U32 dictLimit = ms->window.dictLimit;
496 const BYTE* const prefixStart = base + dictLimit;
497 const BYTE* const dictEnd = dictBase + dictLimit;
William Kurkianea869482019-04-09 15:16:11 -0400498 const U32 current = (U32)(ip-base);
Devmalya Pauleb2e9552019-08-27 19:42:00 -0400499 const U32 maxDistance = 1U << cParams->windowLog;
500 const U32 lowValid = ms->window.lowLimit;
501 const U32 lowLimit = (current - lowValid > maxDistance) ? current - maxDistance : lowValid;
William Kurkianea869482019-04-09 15:16:11 -0400502 const U32 minChain = current > chainSize ? current - chainSize : 0;
503 U32 nbAttempts = 1U << cParams->searchLog;
504 size_t ml=4-1;
505
506 /* HC4 match finder */
507 U32 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls);
508
509 for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) {
510 size_t currentMl=0;
Abhilash S.L3b494632019-07-16 15:51:09 +0530511 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
William Kurkianea869482019-04-09 15:16:11 -0400512 const BYTE* const match = base + matchIndex;
Abhilash S.L3b494632019-07-16 15:51:09 +0530513 assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
William Kurkianea869482019-04-09 15:16:11 -0400514 if (match[ml] == ip[ml]) /* potentially better */
515 currentMl = ZSTD_count(ip, match, iLimit);
516 } else {
517 const BYTE* const match = dictBase + matchIndex;
518 assert(match+4 <= dictEnd);
519 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
520 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
521 }
522
523 /* save best solution */
524 if (currentMl > ml) {
525 ml = currentMl;
526 *offsetPtr = current - matchIndex + ZSTD_REP_MOVE;
527 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
528 }
529
530 if (matchIndex <= minChain) break;
531 matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
532 }
533
Abhilash S.L3b494632019-07-16 15:51:09 +0530534 if (dictMode == ZSTD_dictMatchState) {
535 const ZSTD_matchState_t* const dms = ms->dictMatchState;
536 const U32* const dmsChainTable = dms->chainTable;
537 const U32 dmsChainSize = (1 << dms->cParams.chainLog);
538 const U32 dmsChainMask = dmsChainSize - 1;
539 const U32 dmsLowestIndex = dms->window.dictLimit;
540 const BYTE* const dmsBase = dms->window.base;
541 const BYTE* const dmsEnd = dms->window.nextSrc;
542 const U32 dmsSize = (U32)(dmsEnd - dmsBase);
543 const U32 dmsIndexDelta = dictLimit - dmsSize;
544 const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0;
545
546 matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)];
547
548 for ( ; (matchIndex>dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) {
549 size_t currentMl=0;
550 const BYTE* const match = dmsBase + matchIndex;
551 assert(match+4 <= dmsEnd);
552 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
553 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
554
555 /* save best solution */
556 if (currentMl > ml) {
557 ml = currentMl;
558 *offsetPtr = current - (matchIndex + dmsIndexDelta) + ZSTD_REP_MOVE;
559 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
560 }
561
562 if (matchIndex <= dmsMinChain) break;
563 matchIndex = dmsChainTable[matchIndex & dmsChainMask];
564 }
565 }
566
William Kurkianea869482019-04-09 15:16:11 -0400567 return ml;
568}
569
570
571FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
Abhilash S.L3b494632019-07-16 15:51:09 +0530572 ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -0400573 const BYTE* ip, const BYTE* const iLimit,
574 size_t* offsetPtr)
575{
Abhilash S.L3b494632019-07-16 15:51:09 +0530576 switch(ms->cParams.minMatch)
William Kurkianea869482019-04-09 15:16:11 -0400577 {
578 default : /* includes case 3 */
Abhilash S.L3b494632019-07-16 15:51:09 +0530579 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict);
580 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict);
William Kurkianea869482019-04-09 15:16:11 -0400581 case 7 :
Abhilash S.L3b494632019-07-16 15:51:09 +0530582 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict);
583 }
584}
585
586
587static size_t ZSTD_HcFindBestMatch_dictMatchState_selectMLS (
588 ZSTD_matchState_t* ms,
589 const BYTE* ip, const BYTE* const iLimit,
590 size_t* offsetPtr)
591{
592 switch(ms->cParams.minMatch)
593 {
594 default : /* includes case 3 */
595 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState);
596 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState);
597 case 7 :
598 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState);
William Kurkianea869482019-04-09 15:16:11 -0400599 }
600}
601
602
603FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
Abhilash S.L3b494632019-07-16 15:51:09 +0530604 ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -0400605 const BYTE* ip, const BYTE* const iLimit,
Abhilash S.L3b494632019-07-16 15:51:09 +0530606 size_t* offsetPtr)
William Kurkianea869482019-04-09 15:16:11 -0400607{
Abhilash S.L3b494632019-07-16 15:51:09 +0530608 switch(ms->cParams.minMatch)
William Kurkianea869482019-04-09 15:16:11 -0400609 {
610 default : /* includes case 3 */
Abhilash S.L3b494632019-07-16 15:51:09 +0530611 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict);
612 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict);
William Kurkianea869482019-04-09 15:16:11 -0400613 case 7 :
Abhilash S.L3b494632019-07-16 15:51:09 +0530614 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict);
William Kurkianea869482019-04-09 15:16:11 -0400615 }
616}
617
618
619/* *******************************
620* Common parser - lazy strategy
621*********************************/
622FORCE_INLINE_TEMPLATE
623size_t ZSTD_compressBlock_lazy_generic(
624 ZSTD_matchState_t* ms, seqStore_t* seqStore,
625 U32 rep[ZSTD_REP_NUM],
William Kurkianea869482019-04-09 15:16:11 -0400626 const void* src, size_t srcSize,
Abhilash S.L3b494632019-07-16 15:51:09 +0530627 const U32 searchMethod, const U32 depth,
628 ZSTD_dictMode_e const dictMode)
William Kurkianea869482019-04-09 15:16:11 -0400629{
630 const BYTE* const istart = (const BYTE*)src;
631 const BYTE* ip = istart;
632 const BYTE* anchor = istart;
633 const BYTE* const iend = istart + srcSize;
634 const BYTE* const ilimit = iend - 8;
Abhilash S.L3b494632019-07-16 15:51:09 +0530635 const BYTE* const base = ms->window.base;
636 const U32 prefixLowestIndex = ms->window.dictLimit;
637 const BYTE* const prefixLowest = base + prefixLowestIndex;
William Kurkianea869482019-04-09 15:16:11 -0400638
639 typedef size_t (*searchMax_f)(
Abhilash S.L3b494632019-07-16 15:51:09 +0530640 ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -0400641 const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
Abhilash S.L3b494632019-07-16 15:51:09 +0530642 searchMax_f const searchMax = dictMode == ZSTD_dictMatchState ?
643 (searchMethod ? ZSTD_BtFindBestMatch_dictMatchState_selectMLS : ZSTD_HcFindBestMatch_dictMatchState_selectMLS) :
644 (searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS);
William Kurkianea869482019-04-09 15:16:11 -0400645 U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0;
646
Abhilash S.L3b494632019-07-16 15:51:09 +0530647 const ZSTD_matchState_t* const dms = ms->dictMatchState;
648 const U32 dictLowestIndex = dictMode == ZSTD_dictMatchState ?
649 dms->window.dictLimit : 0;
650 const BYTE* const dictBase = dictMode == ZSTD_dictMatchState ?
651 dms->window.base : NULL;
652 const BYTE* const dictLowest = dictMode == ZSTD_dictMatchState ?
653 dictBase + dictLowestIndex : NULL;
654 const BYTE* const dictEnd = dictMode == ZSTD_dictMatchState ?
655 dms->window.nextSrc : NULL;
656 const U32 dictIndexDelta = dictMode == ZSTD_dictMatchState ?
657 prefixLowestIndex - (U32)(dictEnd - dictBase) :
658 0;
659 const U32 dictAndPrefixLength = (U32)(ip - prefixLowest + dictEnd - dictLowest);
660
William Kurkianea869482019-04-09 15:16:11 -0400661 /* init */
Abhilash S.L3b494632019-07-16 15:51:09 +0530662 ip += (dictAndPrefixLength == 0);
Abhilash S.L3b494632019-07-16 15:51:09 +0530663 if (dictMode == ZSTD_noDict) {
664 U32 const maxRep = (U32)(ip - prefixLowest);
William Kurkianea869482019-04-09 15:16:11 -0400665 if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
666 if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
667 }
Abhilash S.L3b494632019-07-16 15:51:09 +0530668 if (dictMode == ZSTD_dictMatchState) {
669 /* dictMatchState repCode checks don't currently handle repCode == 0
670 * disabling. */
671 assert(offset_1 <= dictAndPrefixLength);
672 assert(offset_2 <= dictAndPrefixLength);
673 }
William Kurkianea869482019-04-09 15:16:11 -0400674
675 /* Match Loop */
676 while (ip < ilimit) {
677 size_t matchLength=0;
678 size_t offset=0;
679 const BYTE* start=ip+1;
680
681 /* check repCode */
Abhilash S.L3b494632019-07-16 15:51:09 +0530682 if (dictMode == ZSTD_dictMatchState) {
683 const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
684 const BYTE* repMatch = (dictMode == ZSTD_dictMatchState
685 && repIndex < prefixLowestIndex) ?
686 dictBase + (repIndex - dictIndexDelta) :
687 base + repIndex;
688 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
689 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
690 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
691 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
692 if (depth==0) goto _storeSequence;
693 }
694 }
695 if ( dictMode == ZSTD_noDict
696 && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
William Kurkianea869482019-04-09 15:16:11 -0400697 matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
698 if (depth==0) goto _storeSequence;
699 }
700
701 /* first search (depth 0) */
Abhilash S.L3b494632019-07-16 15:51:09 +0530702 { size_t offsetFound = 999999999;
703 size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
William Kurkianea869482019-04-09 15:16:11 -0400704 if (ml2 > matchLength)
705 matchLength = ml2, start = ip, offset=offsetFound;
706 }
707
708 if (matchLength < 4) {
709 ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */
710 continue;
711 }
712
713 /* let's try to find a better solution */
714 if (depth>=1)
715 while (ip<ilimit) {
716 ip ++;
Abhilash S.L3b494632019-07-16 15:51:09 +0530717 if ( (dictMode == ZSTD_noDict)
718 && (offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
William Kurkianea869482019-04-09 15:16:11 -0400719 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
720 int const gain2 = (int)(mlRep * 3);
721 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
722 if ((mlRep >= 4) && (gain2 > gain1))
723 matchLength = mlRep, offset = 0, start = ip;
724 }
Abhilash S.L3b494632019-07-16 15:51:09 +0530725 if (dictMode == ZSTD_dictMatchState) {
726 const U32 repIndex = (U32)(ip - base) - offset_1;
727 const BYTE* repMatch = repIndex < prefixLowestIndex ?
728 dictBase + (repIndex - dictIndexDelta) :
729 base + repIndex;
730 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
731 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
732 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
733 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
734 int const gain2 = (int)(mlRep * 3);
735 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
736 if ((mlRep >= 4) && (gain2 > gain1))
737 matchLength = mlRep, offset = 0, start = ip;
738 }
739 }
740 { size_t offset2=999999999;
741 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
William Kurkianea869482019-04-09 15:16:11 -0400742 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */
743 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
744 if ((ml2 >= 4) && (gain2 > gain1)) {
745 matchLength = ml2, offset = offset2, start = ip;
746 continue; /* search a better one */
747 } }
748
749 /* let's find an even better one */
750 if ((depth==2) && (ip<ilimit)) {
751 ip ++;
Abhilash S.L3b494632019-07-16 15:51:09 +0530752 if ( (dictMode == ZSTD_noDict)
753 && (offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
754 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
755 int const gain2 = (int)(mlRep * 4);
William Kurkianea869482019-04-09 15:16:11 -0400756 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
Abhilash S.L3b494632019-07-16 15:51:09 +0530757 if ((mlRep >= 4) && (gain2 > gain1))
758 matchLength = mlRep, offset = 0, start = ip;
William Kurkianea869482019-04-09 15:16:11 -0400759 }
Abhilash S.L3b494632019-07-16 15:51:09 +0530760 if (dictMode == ZSTD_dictMatchState) {
761 const U32 repIndex = (U32)(ip - base) - offset_1;
762 const BYTE* repMatch = repIndex < prefixLowestIndex ?
763 dictBase + (repIndex - dictIndexDelta) :
764 base + repIndex;
765 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
766 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
767 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
768 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
769 int const gain2 = (int)(mlRep * 4);
770 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
771 if ((mlRep >= 4) && (gain2 > gain1))
772 matchLength = mlRep, offset = 0, start = ip;
773 }
774 }
775 { size_t offset2=999999999;
776 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
William Kurkianea869482019-04-09 15:16:11 -0400777 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */
778 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
779 if ((ml2 >= 4) && (gain2 > gain1)) {
780 matchLength = ml2, offset = offset2, start = ip;
781 continue;
782 } } }
783 break; /* nothing found : store previous solution */
784 }
785
786 /* NOTE:
787 * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior.
788 * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which
789 * overflows the pointer, which is undefined behavior.
790 */
791 /* catch up */
792 if (offset) {
Abhilash S.L3b494632019-07-16 15:51:09 +0530793 if (dictMode == ZSTD_noDict) {
794 while ( ((start > anchor) & (start - (offset-ZSTD_REP_MOVE) > prefixLowest))
795 && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) ) /* only search for offset within prefix */
796 { start--; matchLength++; }
797 }
798 if (dictMode == ZSTD_dictMatchState) {
799 U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
800 const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex;
801 const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest;
802 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
803 }
William Kurkianea869482019-04-09 15:16:11 -0400804 offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
805 }
806 /* store sequence */
807_storeSequence:
808 { size_t const litLength = start - anchor;
809 ZSTD_storeSeq(seqStore, litLength, anchor, (U32)offset, matchLength-MINMATCH);
810 anchor = ip = start + matchLength;
811 }
812
813 /* check immediate repcode */
Abhilash S.L3b494632019-07-16 15:51:09 +0530814 if (dictMode == ZSTD_dictMatchState) {
815 while (ip <= ilimit) {
816 U32 const current2 = (U32)(ip-base);
817 U32 const repIndex = current2 - offset_2;
818 const BYTE* repMatch = dictMode == ZSTD_dictMatchState
819 && repIndex < prefixLowestIndex ?
820 dictBase - dictIndexDelta + repIndex :
821 base + repIndex;
822 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */)
823 && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
824 const BYTE* const repEnd2 = repIndex < prefixLowestIndex ? dictEnd : iend;
825 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd2, prefixLowest) + 4;
826 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap offset_2 <=> offset_1 */
827 ZSTD_storeSeq(seqStore, 0, anchor, 0, matchLength-MINMATCH);
828 ip += matchLength;
829 anchor = ip;
830 continue;
831 }
832 break;
833 }
834 }
835
836 if (dictMode == ZSTD_noDict) {
837 while ( ((ip <= ilimit) & (offset_2>0))
838 && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
839 /* store sequence */
840 matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
841 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */
842 ZSTD_storeSeq(seqStore, 0, anchor, 0, matchLength-MINMATCH);
843 ip += matchLength;
844 anchor = ip;
845 continue; /* faster when present ... (?) */
846 } } }
William Kurkianea869482019-04-09 15:16:11 -0400847
848 /* Save reps for next block */
849 rep[0] = offset_1 ? offset_1 : savedOffset;
850 rep[1] = offset_2 ? offset_2 : savedOffset;
851
852 /* Return the last literals size */
853 return iend - anchor;
854}
855
856
857size_t ZSTD_compressBlock_btlazy2(
858 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +0530859 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -0400860{
Abhilash S.L3b494632019-07-16 15:51:09 +0530861 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 1, 2, ZSTD_noDict);
William Kurkianea869482019-04-09 15:16:11 -0400862}
863
864size_t ZSTD_compressBlock_lazy2(
865 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +0530866 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -0400867{
Abhilash S.L3b494632019-07-16 15:51:09 +0530868 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 0, 2, ZSTD_noDict);
William Kurkianea869482019-04-09 15:16:11 -0400869}
870
871size_t ZSTD_compressBlock_lazy(
872 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +0530873 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -0400874{
Abhilash S.L3b494632019-07-16 15:51:09 +0530875 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 0, 1, ZSTD_noDict);
William Kurkianea869482019-04-09 15:16:11 -0400876}
877
878size_t ZSTD_compressBlock_greedy(
879 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +0530880 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -0400881{
Abhilash S.L3b494632019-07-16 15:51:09 +0530882 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 0, 0, ZSTD_noDict);
883}
884
885size_t ZSTD_compressBlock_btlazy2_dictMatchState(
886 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
887 void const* src, size_t srcSize)
888{
889 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 1, 2, ZSTD_dictMatchState);
890}
891
892size_t ZSTD_compressBlock_lazy2_dictMatchState(
893 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
894 void const* src, size_t srcSize)
895{
896 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 0, 2, ZSTD_dictMatchState);
897}
898
899size_t ZSTD_compressBlock_lazy_dictMatchState(
900 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
901 void const* src, size_t srcSize)
902{
903 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 0, 1, ZSTD_dictMatchState);
904}
905
906size_t ZSTD_compressBlock_greedy_dictMatchState(
907 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
908 void const* src, size_t srcSize)
909{
910 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, 0, 0, ZSTD_dictMatchState);
William Kurkianea869482019-04-09 15:16:11 -0400911}
912
913
914FORCE_INLINE_TEMPLATE
915size_t ZSTD_compressBlock_lazy_extDict_generic(
916 ZSTD_matchState_t* ms, seqStore_t* seqStore,
917 U32 rep[ZSTD_REP_NUM],
William Kurkianea869482019-04-09 15:16:11 -0400918 const void* src, size_t srcSize,
919 const U32 searchMethod, const U32 depth)
920{
921 const BYTE* const istart = (const BYTE*)src;
922 const BYTE* ip = istart;
923 const BYTE* anchor = istart;
924 const BYTE* const iend = istart + srcSize;
925 const BYTE* const ilimit = iend - 8;
926 const BYTE* const base = ms->window.base;
927 const U32 dictLimit = ms->window.dictLimit;
928 const U32 lowestIndex = ms->window.lowLimit;
929 const BYTE* const prefixStart = base + dictLimit;
930 const BYTE* const dictBase = ms->window.dictBase;
931 const BYTE* const dictEnd = dictBase + dictLimit;
932 const BYTE* const dictStart = dictBase + lowestIndex;
933
934 typedef size_t (*searchMax_f)(
Abhilash S.L3b494632019-07-16 15:51:09 +0530935 ZSTD_matchState_t* ms,
William Kurkianea869482019-04-09 15:16:11 -0400936 const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
Abhilash S.L3b494632019-07-16 15:51:09 +0530937 searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_extDict_selectMLS : ZSTD_HcFindBestMatch_extDict_selectMLS;
William Kurkianea869482019-04-09 15:16:11 -0400938
939 U32 offset_1 = rep[0], offset_2 = rep[1];
940
941 /* init */
William Kurkianea869482019-04-09 15:16:11 -0400942 ip += (ip == prefixStart);
943
944 /* Match Loop */
945 while (ip < ilimit) {
946 size_t matchLength=0;
947 size_t offset=0;
948 const BYTE* start=ip+1;
949 U32 current = (U32)(ip-base);
950
951 /* check repCode */
952 { const U32 repIndex = (U32)(current+1 - offset_1);
953 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
954 const BYTE* const repMatch = repBase + repIndex;
955 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
956 if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
957 /* repcode detected we should take it */
958 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
959 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4;
960 if (depth==0) goto _storeSequence;
961 } }
962
963 /* first search (depth 0) */
Abhilash S.L3b494632019-07-16 15:51:09 +0530964 { size_t offsetFound = 999999999;
965 size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
William Kurkianea869482019-04-09 15:16:11 -0400966 if (ml2 > matchLength)
967 matchLength = ml2, start = ip, offset=offsetFound;
968 }
969
970 if (matchLength < 4) {
971 ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */
972 continue;
973 }
974
975 /* let's try to find a better solution */
976 if (depth>=1)
977 while (ip<ilimit) {
978 ip ++;
979 current++;
980 /* check repCode */
981 if (offset) {
982 const U32 repIndex = (U32)(current - offset_1);
983 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
984 const BYTE* const repMatch = repBase + repIndex;
985 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
986 if (MEM_read32(ip) == MEM_read32(repMatch)) {
987 /* repcode detected */
988 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
989 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
990 int const gain2 = (int)(repLength * 3);
991 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
992 if ((repLength >= 4) && (gain2 > gain1))
993 matchLength = repLength, offset = 0, start = ip;
994 } }
995
996 /* search match, depth 1 */
Abhilash S.L3b494632019-07-16 15:51:09 +0530997 { size_t offset2=999999999;
998 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
William Kurkianea869482019-04-09 15:16:11 -0400999 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */
1000 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
1001 if ((ml2 >= 4) && (gain2 > gain1)) {
1002 matchLength = ml2, offset = offset2, start = ip;
1003 continue; /* search a better one */
1004 } }
1005
1006 /* let's find an even better one */
1007 if ((depth==2) && (ip<ilimit)) {
1008 ip ++;
1009 current++;
1010 /* check repCode */
1011 if (offset) {
1012 const U32 repIndex = (U32)(current - offset_1);
1013 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
1014 const BYTE* const repMatch = repBase + repIndex;
1015 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
1016 if (MEM_read32(ip) == MEM_read32(repMatch)) {
1017 /* repcode detected */
1018 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
1019 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
1020 int const gain2 = (int)(repLength * 4);
1021 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
1022 if ((repLength >= 4) && (gain2 > gain1))
1023 matchLength = repLength, offset = 0, start = ip;
1024 } }
1025
1026 /* search match, depth 2 */
Abhilash S.L3b494632019-07-16 15:51:09 +05301027 { size_t offset2=999999999;
1028 size_t const ml2 = searchMax(ms, ip, iend, &offset2);
William Kurkianea869482019-04-09 15:16:11 -04001029 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */
1030 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
1031 if ((ml2 >= 4) && (gain2 > gain1)) {
1032 matchLength = ml2, offset = offset2, start = ip;
1033 continue;
1034 } } }
1035 break; /* nothing found : store previous solution */
1036 }
1037
1038 /* catch up */
1039 if (offset) {
1040 U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
1041 const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
1042 const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
1043 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
1044 offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
1045 }
1046
1047 /* store sequence */
1048_storeSequence:
1049 { size_t const litLength = start - anchor;
1050 ZSTD_storeSeq(seqStore, litLength, anchor, (U32)offset, matchLength-MINMATCH);
1051 anchor = ip = start + matchLength;
1052 }
1053
1054 /* check immediate repcode */
1055 while (ip <= ilimit) {
1056 const U32 repIndex = (U32)((ip-base) - offset_2);
1057 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
1058 const BYTE* const repMatch = repBase + repIndex;
1059 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
1060 if (MEM_read32(ip) == MEM_read32(repMatch)) {
1061 /* repcode detected we should take it */
1062 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
1063 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
1064 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap offset history */
1065 ZSTD_storeSeq(seqStore, 0, anchor, 0, matchLength-MINMATCH);
1066 ip += matchLength;
1067 anchor = ip;
1068 continue; /* faster when present ... (?) */
1069 }
1070 break;
1071 } }
1072
1073 /* Save reps for next block */
1074 rep[0] = offset_1;
1075 rep[1] = offset_2;
1076
1077 /* Return the last literals size */
1078 return iend - anchor;
1079}
1080
1081
1082size_t ZSTD_compressBlock_greedy_extDict(
1083 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +05301084 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -04001085{
Abhilash S.L3b494632019-07-16 15:51:09 +05301086 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, 0, 0);
William Kurkianea869482019-04-09 15:16:11 -04001087}
1088
1089size_t ZSTD_compressBlock_lazy_extDict(
1090 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +05301091 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -04001092
1093{
Abhilash S.L3b494632019-07-16 15:51:09 +05301094 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, 0, 1);
William Kurkianea869482019-04-09 15:16:11 -04001095}
1096
1097size_t ZSTD_compressBlock_lazy2_extDict(
1098 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +05301099 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -04001100
1101{
Abhilash S.L3b494632019-07-16 15:51:09 +05301102 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, 0, 2);
William Kurkianea869482019-04-09 15:16:11 -04001103}
1104
1105size_t ZSTD_compressBlock_btlazy2_extDict(
1106 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
Abhilash S.L3b494632019-07-16 15:51:09 +05301107 void const* src, size_t srcSize)
William Kurkianea869482019-04-09 15:16:11 -04001108
1109{
Abhilash S.L3b494632019-07-16 15:51:09 +05301110 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, 1, 2);
William Kurkianea869482019-04-09 15:16:11 -04001111}