1 /*
2 * Copyright (c) Yann Collet, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11 #include "zstd_compress_internal.h"
12 #include "zstd_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 curr = (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] = curr + i;
41 if (i == 0 || hashLarge[lgHash] == 0)
42 hashLarge[lgHash] = curr + 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 /* presumes that, if there is a dictionary, it must be using Attach mode */
67 const U32 prefixLowestIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
68 const BYTE* const prefixLowest = base + prefixLowestIndex;
69 const BYTE* const iend = istart + srcSize;
70 const BYTE* const ilimit = iend - HASH_READ_SIZE;
71 U32 offset_1=rep[0], offset_2=rep[1];
72 U32 offsetSaved = 0;
73
74 const ZSTD_matchState_t* const dms = ms->dictMatchState;
75 const ZSTD_compressionParameters* const dictCParams =
76 dictMode == ZSTD_dictMatchState ?
77 &dms->cParams : NULL;
78 const U32* const dictHashLong = dictMode == ZSTD_dictMatchState ?
79 dms->hashTable : NULL;
80 const U32* const dictHashSmall = dictMode == ZSTD_dictMatchState ?
81 dms->chainTable : NULL;
82 const U32 dictStartIndex = dictMode == ZSTD_dictMatchState ?
83 dms->window.dictLimit : 0;
84 const BYTE* const dictBase = dictMode == ZSTD_dictMatchState ?
85 dms->window.base : NULL;
86 const BYTE* const dictStart = dictMode == ZSTD_dictMatchState ?
87 dictBase + dictStartIndex : NULL;
88 const BYTE* const dictEnd = dictMode == ZSTD_dictMatchState ?
89 dms->window.nextSrc : NULL;
90 const U32 dictIndexDelta = dictMode == ZSTD_dictMatchState ?
91 prefixLowestIndex - (U32)(dictEnd - dictBase) :
92 0;
93 const U32 dictHBitsL = dictMode == ZSTD_dictMatchState ?
94 dictCParams->hashLog : hBitsL;
95 const U32 dictHBitsS = dictMode == ZSTD_dictMatchState ?
96 dictCParams->chainLog : hBitsS;
97 const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictStart));
98
99 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_generic");
100
101 assert(dictMode == ZSTD_noDict || dictMode == ZSTD_dictMatchState);
102
103 /* if a dictionary is attached, it must be within window range */
104 if (dictMode == ZSTD_dictMatchState) {
105 assert(ms->window.dictLimit + (1U << cParams->windowLog) >= endIndex);
106 }
107
108 /* init */
109 ip += (dictAndPrefixLength == 0);
110 if (dictMode == ZSTD_noDict) {
111 U32 const curr = (U32)(ip - base);
112 U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog);
113 U32 const maxRep = curr - windowLow;
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 curr = (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 = curr + 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] = curr; /* 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)(curr - 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 #if defined(__aarch64__)
202 PREFETCH_L1(ip+256);
203 #endif
204 continue;
205
206 _search_next_long:
207
208 { size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
209 size_t const dictHLNext = ZSTD_hashPtr(ip+1, dictHBitsL, 8);
210 U32 const matchIndexL3 = hashLong[hl3];
211 const BYTE* matchL3 = base + matchIndexL3;
212 hashLong[hl3] = curr + 1;
213
214 /* check prefix long +1 match */
215 if (matchIndexL3 > prefixLowestIndex) {
216 if (MEM_read64(matchL3) == MEM_read64(ip+1)) {
217 mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
218 ip++;
219 offset = (U32)(ip-matchL3);
220 while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
221 goto _match_found;
222 }
223 } else if (dictMode == ZSTD_dictMatchState) {
224 /* check dict long +1 match */
225 U32 const dictMatchIndexL3 = dictHashLong[dictHLNext];
226 const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
227 assert(dictMatchL3 < dictEnd);
228 if (dictMatchL3 > dictStart && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) {
229 mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, prefixLowest) + 8;
230 ip++;
231 offset = (U32)(curr + 1 - dictMatchIndexL3 - dictIndexDelta);
232 while (((ip>anchor) & (dictMatchL3>dictStart)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */
233 goto _match_found;
234 } } }
235
236 /* if no long +1 match, explore the short match we found */
237 if (dictMode == ZSTD_dictMatchState && matchIndexS < prefixLowestIndex) {
238 mLength = ZSTD_count_2segments(ip+4, match+4, iend, dictEnd, prefixLowest) + 4;
239 offset = (U32)(curr - matchIndexS);
240 while (((ip>anchor) & (match>dictStart)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
241 } else {
242 mLength = ZSTD_count(ip+4, match+4, iend) + 4;
243 offset = (U32)(ip - match);
244 while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
245 }
246
247 _match_found:
248 offset_2 = offset_1;
249 offset_1 = offset;
250
251 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
252
253 _match_stored:
254 /* match found */
255 ip += mLength;
256 anchor = ip;
257
258 if (ip <= ilimit) {
259 /* Complementary insertion */
260 /* done after iLimit test, as candidates could be > iend-8 */
261 { U32 const indexToInsert = curr+2;
262 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
263 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
264 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
265 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
266 }
267
268 /* check immediate repcode */
269 if (dictMode == ZSTD_dictMatchState) {
270 while (ip <= ilimit) {
271 U32 const current2 = (U32)(ip-base);
272 U32 const repIndex2 = current2 - offset_2;
273 const BYTE* repMatch2 = dictMode == ZSTD_dictMatchState
274 && repIndex2 < prefixLowestIndex ?
275 dictBase + repIndex2 - dictIndexDelta :
276 base + repIndex2;
277 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */)
278 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
279 const BYTE* const repEnd2 = repIndex2 < prefixLowestIndex ? dictEnd : iend;
280 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixLowest) + 4;
281 U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
282 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
283 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
284 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
285 ip += repLength2;
286 anchor = ip;
287 continue;
288 }
289 break;
290 } }
291
292 if (dictMode == ZSTD_noDict) {
293 while ( (ip <= ilimit)
294 && ( (offset_2>0)
295 & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
296 /* store sequence */
297 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
298 U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */
299 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
300 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
301 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, rLength-MINMATCH);
302 ip += rLength;
303 anchor = ip;
304 continue; /* faster when present ... (?) */
305 } } }
306 } /* while (ip < ilimit) */
307
308 /* save reps for next block */
309 rep[0] = offset_1 ? offset_1 : offsetSaved;
310 rep[1] = offset_2 ? offset_2 : offsetSaved;
311
312 /* Return the last literals size */
313 return (size_t)(iend - anchor);
314 }
315
316
ZSTD_compressBlock_doubleFast(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)317 size_t ZSTD_compressBlock_doubleFast(
318 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
319 void const* src, size_t srcSize)
320 {
321 const U32 mls = ms->cParams.minMatch;
322 switch(mls)
323 {
324 default: /* includes case 3 */
325 case 4 :
326 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_noDict);
327 case 5 :
328 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_noDict);
329 case 6 :
330 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_noDict);
331 case 7 :
332 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_noDict);
333 }
334 }
335
336
ZSTD_compressBlock_doubleFast_dictMatchState(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)337 size_t ZSTD_compressBlock_doubleFast_dictMatchState(
338 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
339 void const* src, size_t srcSize)
340 {
341 const U32 mls = ms->cParams.minMatch;
342 switch(mls)
343 {
344 default: /* includes case 3 */
345 case 4 :
346 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_dictMatchState);
347 case 5 :
348 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_dictMatchState);
349 case 6 :
350 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_dictMatchState);
351 case 7 :
352 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_dictMatchState);
353 }
354 }
355
356
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)357 static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
358 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
359 void const* src, size_t srcSize,
360 U32 const mls /* template */)
361 {
362 ZSTD_compressionParameters const* cParams = &ms->cParams;
363 U32* const hashLong = ms->hashTable;
364 U32 const hBitsL = cParams->hashLog;
365 U32* const hashSmall = ms->chainTable;
366 U32 const hBitsS = cParams->chainLog;
367 const BYTE* const istart = (const BYTE*)src;
368 const BYTE* ip = istart;
369 const BYTE* anchor = istart;
370 const BYTE* const iend = istart + srcSize;
371 const BYTE* const ilimit = iend - 8;
372 const BYTE* const base = ms->window.base;
373 const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
374 const U32 lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
375 const U32 dictStartIndex = lowLimit;
376 const U32 dictLimit = ms->window.dictLimit;
377 const U32 prefixStartIndex = (dictLimit > lowLimit) ? dictLimit : lowLimit;
378 const BYTE* const prefixStart = base + prefixStartIndex;
379 const BYTE* const dictBase = ms->window.dictBase;
380 const BYTE* const dictStart = dictBase + dictStartIndex;
381 const BYTE* const dictEnd = dictBase + prefixStartIndex;
382 U32 offset_1=rep[0], offset_2=rep[1];
383
384 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_extDict_generic (srcSize=%zu)", srcSize);
385
386 /* if extDict is invalidated due to maxDistance, switch to "regular" variant */
387 if (prefixStartIndex == dictStartIndex)
388 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, mls, ZSTD_noDict);
389
390 /* Search Loop */
391 while (ip < ilimit) { /* < instead of <=, because (ip+1) */
392 const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
393 const U32 matchIndex = hashSmall[hSmall];
394 const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
395 const BYTE* match = matchBase + matchIndex;
396
397 const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
398 const U32 matchLongIndex = hashLong[hLong];
399 const BYTE* const matchLongBase = matchLongIndex < prefixStartIndex ? dictBase : base;
400 const BYTE* matchLong = matchLongBase + matchLongIndex;
401
402 const U32 curr = (U32)(ip-base);
403 const U32 repIndex = curr + 1 - offset_1; /* offset_1 expected <= curr +1 */
404 const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
405 const BYTE* const repMatch = repBase + repIndex;
406 size_t mLength;
407 hashSmall[hSmall] = hashLong[hLong] = curr; /* update hash table */
408
409 if ((((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex doesn't overlap dict + prefix */
410 & (repIndex > dictStartIndex))
411 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
412 const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
413 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
414 ip++;
415 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
416 } else {
417 if ((matchLongIndex > dictStartIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
418 const BYTE* const matchEnd = matchLongIndex < prefixStartIndex ? dictEnd : iend;
419 const BYTE* const lowMatchPtr = matchLongIndex < prefixStartIndex ? dictStart : prefixStart;
420 U32 offset;
421 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, prefixStart) + 8;
422 offset = curr - matchLongIndex;
423 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
424 offset_2 = offset_1;
425 offset_1 = offset;
426 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
427
428 } else if ((matchIndex > dictStartIndex) && (MEM_read32(match) == MEM_read32(ip))) {
429 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
430 U32 const matchIndex3 = hashLong[h3];
431 const BYTE* const match3Base = matchIndex3 < prefixStartIndex ? dictBase : base;
432 const BYTE* match3 = match3Base + matchIndex3;
433 U32 offset;
434 hashLong[h3] = curr + 1;
435 if ( (matchIndex3 > dictStartIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
436 const BYTE* const matchEnd = matchIndex3 < prefixStartIndex ? dictEnd : iend;
437 const BYTE* const lowMatchPtr = matchIndex3 < prefixStartIndex ? dictStart : prefixStart;
438 mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, prefixStart) + 8;
439 ip++;
440 offset = curr+1 - matchIndex3;
441 while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
442 } else {
443 const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
444 const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
445 mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
446 offset = curr - matchIndex;
447 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
448 }
449 offset_2 = offset_1;
450 offset_1 = offset;
451 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
452
453 } else {
454 ip += ((ip-anchor) >> kSearchStrength) + 1;
455 continue;
456 } }
457
458 /* move to next sequence start */
459 ip += mLength;
460 anchor = ip;
461
462 if (ip <= ilimit) {
463 /* Complementary insertion */
464 /* done after iLimit test, as candidates could be > iend-8 */
465 { U32 const indexToInsert = curr+2;
466 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
467 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
468 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
469 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
470 }
471
472 /* check immediate repcode */
473 while (ip <= ilimit) {
474 U32 const current2 = (U32)(ip-base);
475 U32 const repIndex2 = current2 - offset_2;
476 const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
477 if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) /* intentional overflow : ensure repIndex2 doesn't overlap dict + prefix */
478 & (repIndex2 > dictStartIndex))
479 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
480 const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
481 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
482 U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
483 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
484 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
485 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
486 ip += repLength2;
487 anchor = ip;
488 continue;
489 }
490 break;
491 } } }
492
493 /* save reps for next block */
494 rep[0] = offset_1;
495 rep[1] = offset_2;
496
497 /* Return the last literals size */
498 return (size_t)(iend - anchor);
499 }
500
501
ZSTD_compressBlock_doubleFast_extDict(ZSTD_matchState_t * ms,seqStore_t * seqStore,U32 rep[ZSTD_REP_NUM],void const * src,size_t srcSize)502 size_t ZSTD_compressBlock_doubleFast_extDict(
503 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
504 void const* src, size_t srcSize)
505 {
506 U32 const mls = ms->cParams.minMatch;
507 switch(mls)
508 {
509 default: /* includes case 3 */
510 case 4 :
511 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 4);
512 case 5 :
513 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 5);
514 case 6 :
515 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 6);
516 case 7 :
517 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 7);
518 }
519 }
520