1 /*
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_double_fast.h"
13
14
ZSTD_fillDoubleHashTable(ZSTD_matchState_t * ms,void const * end,ZSTD_dictTableLoadMethod_e dtlm)15 void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms,
16 void const* end, ZSTD_dictTableLoadMethod_e dtlm)
17 {
18 const ZSTD_compressionParameters* const cParams = &ms->cParams;
19 U32* const hashLarge = ms->hashTable;
20 U32 const hBitsL = cParams->hashLog;
21 U32 const mls = cParams->minMatch;
22 U32* const hashSmall = ms->chainTable;
23 U32 const hBitsS = cParams->chainLog;
24 const BYTE* const base = ms->window.base;
25 const BYTE* ip = base + ms->nextToUpdate;
26 const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
27 const U32 fastHashFillStep = 3;
28
29 /* Always insert every fastHashFillStep position into the hash tables.
30 * Insert the other positions into the large hash table if their entry
31 * is empty.
32 */
33 for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) {
34 U32 const current = (U32)(ip - base);
35 U32 i;
36 for (i = 0; i < fastHashFillStep; ++i) {
37 size_t const smHash = ZSTD_hashPtr(ip + i, hBitsS, mls);
38 size_t const lgHash = ZSTD_hashPtr(ip + i, hBitsL, 8);
39 if (i == 0)
40 hashSmall[smHash] = current + i;
41 if (i == 0 || hashLarge[lgHash] == 0)
42 hashLarge[lgHash] = current + i;
43 /* Only load extra positions for ZSTD_dtlm_full */
44 if (dtlm == ZSTD_dtlm_fast)
45 break;
46 } }
47 }
48
49
50 FORCE_INLINE_TEMPLATE
ZSTD_compressBlock_doubleFast_generic(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize,U32 const mls,ZSTD_dictMode_e const dictMode)51 size_t ZSTD_compressBlock_doubleFast_generic(
52 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
53 void const* src, size_t srcSize,
54 U32 const mls /* template */, ZSTD_dictMode_e const dictMode)
55 {
56 ZSTD_compressionParameters const* cParams = &ms->cParams;
57 U32* const hashLong = ms->hashTable;
58 const U32 hBitsL = cParams->hashLog;
59 U32* const hashSmall = ms->chainTable;
60 const U32 hBitsS = cParams->chainLog;
61 const BYTE* const base = ms->window.base;
62 const BYTE* const istart = (const BYTE*)src;
63 const BYTE* ip = istart;
64 const BYTE* anchor = istart;
65 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
66 const U32 lowestValid = ms->window.dictLimit;
67 const U32 maxDistance = 1U << cParams->windowLog;
68 /* presumes that, if there is a dictionary, it must be using Attach mode */
69 const U32 prefixLowestIndex = (endIndex - lowestValid > maxDistance) ? endIndex - maxDistance : lowestValid;
70 const BYTE* const prefixLowest = base + prefixLowestIndex;
71 const BYTE* const iend = istart + srcSize;
72 const BYTE* const ilimit = iend - HASH_READ_SIZE;
73 U32 offset_1=rep[0], offset_2=rep[1];
74 U32 offsetSaved = 0;
75
76 const ZSTD_matchState_t* const dms = ms->dictMatchState;
77 const ZSTD_compressionParameters* const dictCParams =
78 dictMode == ZSTD_dictMatchState ?
79 &dms->cParams : NULL;
80 const U32* const dictHashLong = dictMode == ZSTD_dictMatchState ?
81 dms->hashTable : NULL;
82 const U32* const dictHashSmall = dictMode == ZSTD_dictMatchState ?
83 dms->chainTable : NULL;
84 const U32 dictStartIndex = dictMode == ZSTD_dictMatchState ?
85 dms->window.dictLimit : 0;
86 const BYTE* const dictBase = dictMode == ZSTD_dictMatchState ?
87 dms->window.base : NULL;
88 const BYTE* const dictStart = dictMode == ZSTD_dictMatchState ?
89 dictBase + dictStartIndex : NULL;
90 const BYTE* const dictEnd = dictMode == ZSTD_dictMatchState ?
91 dms->window.nextSrc : NULL;
92 const U32 dictIndexDelta = dictMode == ZSTD_dictMatchState ?
93 prefixLowestIndex - (U32)(dictEnd - dictBase) :
94 0;
95 const U32 dictHBitsL = dictMode == ZSTD_dictMatchState ?
96 dictCParams->hashLog : hBitsL;
97 const U32 dictHBitsS = dictMode == ZSTD_dictMatchState ?
98 dictCParams->chainLog : hBitsS;
99 const U32 dictAndPrefixLength = (U32)(ip - prefixLowest + dictEnd - dictStart);
100
101 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_generic");
102
103 assert(dictMode == ZSTD_noDict || dictMode == ZSTD_dictMatchState);
104
105 /* if a dictionary is attached, it must be within window range */
106 if (dictMode == ZSTD_dictMatchState) {
107 assert(lowestValid + maxDistance >= endIndex);
108 }
109
110 /* init */
111 ip += (dictAndPrefixLength == 0);
112 if (dictMode == ZSTD_noDict) {
113 U32 const maxRep = (U32)(ip - prefixLowest);
114 if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
115 if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
116 }
117 if (dictMode == ZSTD_dictMatchState) {
118 /* dictMatchState repCode checks don't currently handle repCode == 0
119 * disabling. */
120 assert(offset_1 <= dictAndPrefixLength);
121 assert(offset_2 <= dictAndPrefixLength);
122 }
123
124 /* Main Search Loop */
125 while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
126 size_t mLength;
127 U32 offset;
128 size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
129 size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
130 size_t const dictHL = ZSTD_hashPtr(ip, dictHBitsL, 8);
131 size_t const dictHS = ZSTD_hashPtr(ip, dictHBitsS, mls);
132 U32 const current = (U32)(ip-base);
133 U32 const matchIndexL = hashLong[h2];
134 U32 matchIndexS = hashSmall[h];
135 const BYTE* matchLong = base + matchIndexL;
136 const BYTE* match = base + matchIndexS;
137 const U32 repIndex = current + 1 - offset_1;
138 const BYTE* repMatch = (dictMode == ZSTD_dictMatchState
139 && repIndex < prefixLowestIndex) ?
140 dictBase + (repIndex - dictIndexDelta) :
141 base + repIndex;
142 hashLong[h2] = hashSmall[h] = current; /* update hash tables */
143
144 /* check dictMatchState repcode */
145 if (dictMode == ZSTD_dictMatchState
146 && ((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
147 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
148 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
149 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
150 ip++;
151 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
152 goto _match_stored;
153 }
154
155 /* check noDict repcode */
156 if ( dictMode == ZSTD_noDict
157 && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
158 mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
159 ip++;
160 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
161 goto _match_stored;
162 }
163
164 if (matchIndexL > prefixLowestIndex) {
165 /* check prefix long match */
166 if (MEM_read64(matchLong) == MEM_read64(ip)) {
167 mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
168 offset = (U32)(ip-matchLong);
169 while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
170 goto _match_found;
171 }
172 } else if (dictMode == ZSTD_dictMatchState) {
173 /* check dictMatchState long match */
174 U32 const dictMatchIndexL = dictHashLong[dictHL];
175 const BYTE* dictMatchL = dictBase + dictMatchIndexL;
176 assert(dictMatchL < dictEnd);
177
178 if (dictMatchL > dictStart && MEM_read64(dictMatchL) == MEM_read64(ip)) {
179 mLength = ZSTD_count_2segments(ip+8, dictMatchL+8, iend, dictEnd, prefixLowest) + 8;
180 offset = (U32)(current - dictMatchIndexL - dictIndexDelta);
181 while (((ip>anchor) & (dictMatchL>dictStart)) && (ip[-1] == dictMatchL[-1])) { ip--; dictMatchL--; mLength++; } /* catch up */
182 goto _match_found;
183 } }
184
185 if (matchIndexS > prefixLowestIndex) {
186 /* check prefix short match */
187 if (MEM_read32(match) == MEM_read32(ip)) {
188 goto _search_next_long;
189 }
190 } else if (dictMode == ZSTD_dictMatchState) {
191 /* check dictMatchState short match */
192 U32 const dictMatchIndexS = dictHashSmall[dictHS];
193 match = dictBase + dictMatchIndexS;
194 matchIndexS = dictMatchIndexS + dictIndexDelta;
195
196 if (match > dictStart && MEM_read32(match) == MEM_read32(ip)) {
197 goto _search_next_long;
198 } }
199
200 ip += ((ip-anchor) >> kSearchStrength) + 1;
201 continue;
202
203 _search_next_long:
204
205 { size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
206 size_t const dictHLNext = ZSTD_hashPtr(ip+1, dictHBitsL, 8);
207 U32 const matchIndexL3 = hashLong[hl3];
208 const BYTE* matchL3 = base + matchIndexL3;
209 hashLong[hl3] = current + 1;
210
211 /* check prefix long +1 match */
212 if (matchIndexL3 > prefixLowestIndex) {
213 if (MEM_read64(matchL3) == MEM_read64(ip+1)) {
214 mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
215 ip++;
216 offset = (U32)(ip-matchL3);
217 while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
218 goto _match_found;
219 }
220 } else if (dictMode == ZSTD_dictMatchState) {
221 /* check dict long +1 match */
222 U32 const dictMatchIndexL3 = dictHashLong[dictHLNext];
223 const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
224 assert(dictMatchL3 < dictEnd);
225 if (dictMatchL3 > dictStart && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) {
226 mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, prefixLowest) + 8;
227 ip++;
228 offset = (U32)(current + 1 - dictMatchIndexL3 - dictIndexDelta);
229 while (((ip>anchor) & (dictMatchL3>dictStart)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */
230 goto _match_found;
231 } } }
232
233 /* if no long +1 match, explore the short match we found */
234 if (dictMode == ZSTD_dictMatchState && matchIndexS < prefixLowestIndex) {
235 mLength = ZSTD_count_2segments(ip+4, match+4, iend, dictEnd, prefixLowest) + 4;
236 offset = (U32)(current - matchIndexS);
237 while (((ip>anchor) & (match>dictStart)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
238 } else {
239 mLength = ZSTD_count(ip+4, match+4, iend) + 4;
240 offset = (U32)(ip - match);
241 while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
242 }
243
244 /* fall-through */
245
246 _match_found:
247 offset_2 = offset_1;
248 offset_1 = offset;
249
250 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
251
252 _match_stored:
253 /* match found */
254 ip += mLength;
255 anchor = ip;
256
257 if (ip <= ilimit) {
258 /* Complementary insertion */
259 /* done after iLimit test, as candidates could be > iend-8 */
260 { U32 const indexToInsert = current+2;
261 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
262 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
263 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
264 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
265 }
266
267 /* check immediate repcode */
268 if (dictMode == ZSTD_dictMatchState) {
269 while (ip <= ilimit) {
270 U32 const current2 = (U32)(ip-base);
271 U32 const repIndex2 = current2 - offset_2;
272 const BYTE* repMatch2 = dictMode == ZSTD_dictMatchState
273 && repIndex2 < prefixLowestIndex ?
274 dictBase - dictIndexDelta + repIndex2 :
275 base + repIndex2;
276 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */)
277 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
278 const BYTE* const repEnd2 = repIndex2 < prefixLowestIndex ? dictEnd : iend;
279 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixLowest) + 4;
280 U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
281 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
282 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
283 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
284 ip += repLength2;
285 anchor = ip;
286 continue;
287 }
288 break;
289 } }
290
291 if (dictMode == ZSTD_noDict) {
292 while ( (ip <= ilimit)
293 && ( (offset_2>0)
294 & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
295 /* store sequence */
296 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
297 U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */
298 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
299 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
300 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, rLength-MINMATCH);
301 ip += rLength;
302 anchor = ip;
303 continue; /* faster when present ... (?) */
304 } } }
305 } /* while (ip < ilimit) */
306
307 /* save reps for next block */
308 rep[0] = offset_1 ? offset_1 : offsetSaved;
309 rep[1] = offset_2 ? offset_2 : offsetSaved;
310
311 /* Return the last literals size */
312 return (size_t)(iend - anchor);
313 }
314
315
ZSTD_compressBlock_doubleFast(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)316 size_t ZSTD_compressBlock_doubleFast(
317 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
318 void const* src, size_t srcSize)
319 {
320 const U32 mls = ms->cParams.minMatch;
321 switch(mls)
322 {
323 default: /* includes case 3 */
324 case 4 :
325 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_noDict);
326 case 5 :
327 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_noDict);
328 case 6 :
329 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_noDict);
330 case 7 :
331 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_noDict);
332 }
333 }
334
335
ZSTD_compressBlock_doubleFast_dictMatchState(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)336 size_t ZSTD_compressBlock_doubleFast_dictMatchState(
337 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
338 void const* src, size_t srcSize)
339 {
340 const U32 mls = ms->cParams.minMatch;
341 switch(mls)
342 {
343 default: /* includes case 3 */
344 case 4 :
345 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_dictMatchState);
346 case 5 :
347 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_dictMatchState);
348 case 6 :
349 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_dictMatchState);
350 case 7 :
351 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_dictMatchState);
352 }
353 }
354
355
ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize,U32 const mls)356 static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
357 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
358 void const* src, size_t srcSize,
359 U32 const mls /* template */)
360 {
361 ZSTD_compressionParameters const* cParams = &ms->cParams;
362 U32* const hashLong = ms->hashTable;
363 U32 const hBitsL = cParams->hashLog;
364 U32* const hashSmall = ms->chainTable;
365 U32 const hBitsS = cParams->chainLog;
366 const BYTE* const istart = (const BYTE*)src;
367 const BYTE* ip = istart;
368 const BYTE* anchor = istart;
369 const BYTE* const iend = istart + srcSize;
370 const BYTE* const ilimit = iend - 8;
371 const BYTE* const base = ms->window.base;
372 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
373 const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
374 const U32 dictStartIndex = lowLimit;
375 const U32 dictLimit = ms->window.dictLimit;
376 const U32 prefixStartIndex = (dictLimit > lowLimit) ? dictLimit : lowLimit;
377 const BYTE* const prefixStart = base + prefixStartIndex;
378 const BYTE* const dictBase = ms->window.dictBase;
379 const BYTE* const dictStart = dictBase + dictStartIndex;
380 const BYTE* const dictEnd = dictBase + prefixStartIndex;
381 U32 offset_1=rep[0], offset_2=rep[1];
382
383 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_extDict_generic (srcSize=%zu)", srcSize);
384
385 /* if extDict is invalidated due to maxDistance, switch to "regular" variant */
386 if (prefixStartIndex == dictStartIndex)
387 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, mls, ZSTD_noDict);
388
389 /* Search Loop */
390 while (ip < ilimit) { /* < instead of <=, because (ip+1) */
391 const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
392 const U32 matchIndex = hashSmall[hSmall];
393 const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
394 const BYTE* match = matchBase + matchIndex;
395
396 const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
397 const U32 matchLongIndex = hashLong[hLong];
398 const BYTE* const matchLongBase = matchLongIndex < prefixStartIndex ? dictBase : base;
399 const BYTE* matchLong = matchLongBase + matchLongIndex;
400
401 const U32 current = (U32)(ip-base);
402 const U32 repIndex = current + 1 - offset_1; /* offset_1 expected <= current +1 */
403 const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
404 const BYTE* const repMatch = repBase + repIndex;
405 size_t mLength;
406 hashSmall[hSmall] = hashLong[hLong] = current; /* update hash table */
407
408 if ((((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex doesn't overlap dict + prefix */
409 & (repIndex > dictStartIndex))
410 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
411 const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
412 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
413 ip++;
414 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
415 } else {
416 if ((matchLongIndex > dictStartIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
417 const BYTE* const matchEnd = matchLongIndex < prefixStartIndex ? dictEnd : iend;
418 const BYTE* const lowMatchPtr = matchLongIndex < prefixStartIndex ? dictStart : prefixStart;
419 U32 offset;
420 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, prefixStart) + 8;
421 offset = current - matchLongIndex;
422 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
423 offset_2 = offset_1;
424 offset_1 = offset;
425 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
426
427 } else if ((matchIndex > dictStartIndex) && (MEM_read32(match) == MEM_read32(ip))) {
428 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
429 U32 const matchIndex3 = hashLong[h3];
430 const BYTE* const match3Base = matchIndex3 < prefixStartIndex ? dictBase : base;
431 const BYTE* match3 = match3Base + matchIndex3;
432 U32 offset;
433 hashLong[h3] = current + 1;
434 if ( (matchIndex3 > dictStartIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
435 const BYTE* const matchEnd = matchIndex3 < prefixStartIndex ? dictEnd : iend;
436 const BYTE* const lowMatchPtr = matchIndex3 < prefixStartIndex ? dictStart : prefixStart;
437 mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, prefixStart) + 8;
438 ip++;
439 offset = current+1 - matchIndex3;
440 while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
441 } else {
442 const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
443 const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
444 mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
445 offset = current - matchIndex;
446 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
447 }
448 offset_2 = offset_1;
449 offset_1 = offset;
450 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
451
452 } else {
453 ip += ((ip-anchor) >> kSearchStrength) + 1;
454 continue;
455 } }
456
457 /* move to next sequence start */
458 ip += mLength;
459 anchor = ip;
460
461 if (ip <= ilimit) {
462 /* Complementary insertion */
463 /* done after iLimit test, as candidates could be > iend-8 */
464 { U32 const indexToInsert = current+2;
465 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
466 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
467 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
468 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
469 }
470
471 /* check immediate repcode */
472 while (ip <= ilimit) {
473 U32 const current2 = (U32)(ip-base);
474 U32 const repIndex2 = current2 - offset_2;
475 const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
476 if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) /* intentional overflow : ensure repIndex2 doesn't overlap dict + prefix */
477 & (repIndex2 > dictStartIndex))
478 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
479 const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
480 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
481 U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
482 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
483 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
484 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
485 ip += repLength2;
486 anchor = ip;
487 continue;
488 }
489 break;
490 } } }
491
492 /* save reps for next block */
493 rep[0] = offset_1;
494 rep[1] = offset_2;
495
496 /* Return the last literals size */
497 return (size_t)(iend - anchor);
498 }
499
500
ZSTD_compressBlock_doubleFast_extDict(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)501 size_t ZSTD_compressBlock_doubleFast_extDict(
502 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
503 void const* src, size_t srcSize)
504 {
505 U32 const mls = ms->cParams.minMatch;
506 switch(mls)
507 {
508 default: /* includes case 3 */
509 case 4 :
510 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 4);
511 case 5 :
512 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 5);
513 case 6 :
514 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 6);
515 case 7 :
516 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 7);
517 }
518 }
519