1 /**
2  * Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
3  * All rights reserved.
4  *
5  * This source code is licensed under the BSD-style license found in the
6  * LICENSE file in the root directory of https://github.com/facebook/zstd.
7  *
8  * This program is free software; you can redistribute it and/or modify it under
9  * the terms of the GNU General Public License version 2 as published by the
10  * Free Software Foundation. This program is dual-licensed; you may select
11  * either version 2 of the GNU General Public License ("GPL") or BSD license
12  * ("BSD").
13  */
14 
15 /* Note : this file is intended to be included within zstd_compress.c */
16 
17 #ifndef ZSTD_OPT_H_91842398743
18 #define ZSTD_OPT_H_91842398743
19 
20 #define ZSTD_LITFREQ_ADD 2
21 #define ZSTD_FREQ_DIV 4
22 #define ZSTD_MAX_PRICE (1 << 30)
23 
24 /*-*************************************
25 *  Price functions for optimal parser
26 ***************************************/
ZSTD_setLog2Prices(seqStore_t * ssPtr)27 FORCE_INLINE void ZSTD_setLog2Prices(seqStore_t *ssPtr)
28 {
29 	ssPtr->log2matchLengthSum = ZSTD_highbit32(ssPtr->matchLengthSum + 1);
30 	ssPtr->log2litLengthSum = ZSTD_highbit32(ssPtr->litLengthSum + 1);
31 	ssPtr->log2litSum = ZSTD_highbit32(ssPtr->litSum + 1);
32 	ssPtr->log2offCodeSum = ZSTD_highbit32(ssPtr->offCodeSum + 1);
33 	ssPtr->factor = 1 + ((ssPtr->litSum >> 5) / ssPtr->litLengthSum) + ((ssPtr->litSum << 1) / (ssPtr->litSum + ssPtr->matchSum));
34 }
35 
ZSTD_rescaleFreqs(seqStore_t * ssPtr,const BYTE * src,size_t srcSize)36 ZSTD_STATIC void ZSTD_rescaleFreqs(seqStore_t *ssPtr, const BYTE *src, size_t srcSize)
37 {
38 	unsigned u;
39 
40 	ssPtr->cachedLiterals = NULL;
41 	ssPtr->cachedPrice = ssPtr->cachedLitLength = 0;
42 	ssPtr->staticPrices = 0;
43 
44 	if (ssPtr->litLengthSum == 0) {
45 		if (srcSize <= 1024)
46 			ssPtr->staticPrices = 1;
47 
48 		for (u = 0; u <= MaxLit; u++)
49 			ssPtr->litFreq[u] = 0;
50 		for (u = 0; u < srcSize; u++)
51 			ssPtr->litFreq[src[u]]++;
52 
53 		ssPtr->litSum = 0;
54 		ssPtr->litLengthSum = MaxLL + 1;
55 		ssPtr->matchLengthSum = MaxML + 1;
56 		ssPtr->offCodeSum = (MaxOff + 1);
57 		ssPtr->matchSum = (ZSTD_LITFREQ_ADD << Litbits);
58 
59 		for (u = 0; u <= MaxLit; u++) {
60 			ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u] >> ZSTD_FREQ_DIV);
61 			ssPtr->litSum += ssPtr->litFreq[u];
62 		}
63 		for (u = 0; u <= MaxLL; u++)
64 			ssPtr->litLengthFreq[u] = 1;
65 		for (u = 0; u <= MaxML; u++)
66 			ssPtr->matchLengthFreq[u] = 1;
67 		for (u = 0; u <= MaxOff; u++)
68 			ssPtr->offCodeFreq[u] = 1;
69 	} else {
70 		ssPtr->matchLengthSum = 0;
71 		ssPtr->litLengthSum = 0;
72 		ssPtr->offCodeSum = 0;
73 		ssPtr->matchSum = 0;
74 		ssPtr->litSum = 0;
75 
76 		for (u = 0; u <= MaxLit; u++) {
77 			ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u] >> (ZSTD_FREQ_DIV + 1));
78 			ssPtr->litSum += ssPtr->litFreq[u];
79 		}
80 		for (u = 0; u <= MaxLL; u++) {
81 			ssPtr->litLengthFreq[u] = 1 + (ssPtr->litLengthFreq[u] >> (ZSTD_FREQ_DIV + 1));
82 			ssPtr->litLengthSum += ssPtr->litLengthFreq[u];
83 		}
84 		for (u = 0; u <= MaxML; u++) {
85 			ssPtr->matchLengthFreq[u] = 1 + (ssPtr->matchLengthFreq[u] >> ZSTD_FREQ_DIV);
86 			ssPtr->matchLengthSum += ssPtr->matchLengthFreq[u];
87 			ssPtr->matchSum += ssPtr->matchLengthFreq[u] * (u + 3);
88 		}
89 		ssPtr->matchSum *= ZSTD_LITFREQ_ADD;
90 		for (u = 0; u <= MaxOff; u++) {
91 			ssPtr->offCodeFreq[u] = 1 + (ssPtr->offCodeFreq[u] >> ZSTD_FREQ_DIV);
92 			ssPtr->offCodeSum += ssPtr->offCodeFreq[u];
93 		}
94 	}
95 
96 	ZSTD_setLog2Prices(ssPtr);
97 }
98 
ZSTD_getLiteralPrice(seqStore_t * ssPtr,U32 litLength,const BYTE * literals)99 FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t *ssPtr, U32 litLength, const BYTE *literals)
100 {
101 	U32 price, u;
102 
103 	if (ssPtr->staticPrices)
104 		return ZSTD_highbit32((U32)litLength + 1) + (litLength * 6);
105 
106 	if (litLength == 0)
107 		return ssPtr->log2litLengthSum - ZSTD_highbit32(ssPtr->litLengthFreq[0] + 1);
108 
109 	/* literals */
110 	if (ssPtr->cachedLiterals == literals) {
111 		U32 const additional = litLength - ssPtr->cachedLitLength;
112 		const BYTE *literals2 = ssPtr->cachedLiterals + ssPtr->cachedLitLength;
113 		price = ssPtr->cachedPrice + additional * ssPtr->log2litSum;
114 		for (u = 0; u < additional; u++)
115 			price -= ZSTD_highbit32(ssPtr->litFreq[literals2[u]] + 1);
116 		ssPtr->cachedPrice = price;
117 		ssPtr->cachedLitLength = litLength;
118 	} else {
119 		price = litLength * ssPtr->log2litSum;
120 		for (u = 0; u < litLength; u++)
121 			price -= ZSTD_highbit32(ssPtr->litFreq[literals[u]] + 1);
122 
123 		if (litLength >= 12) {
124 			ssPtr->cachedLiterals = literals;
125 			ssPtr->cachedPrice = price;
126 			ssPtr->cachedLitLength = litLength;
127 		}
128 	}
129 
130 	/* literal Length */
131 	{
132 		const BYTE LL_deltaCode = 19;
133 		const BYTE llCode = (litLength > 63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
134 		price += LL_bits[llCode] + ssPtr->log2litLengthSum - ZSTD_highbit32(ssPtr->litLengthFreq[llCode] + 1);
135 	}
136 
137 	return price;
138 }
139 
ZSTD_getPrice(seqStore_t * seqStorePtr,U32 litLength,const BYTE * literals,U32 offset,U32 matchLength,const int ultra)140 FORCE_INLINE U32 ZSTD_getPrice(seqStore_t *seqStorePtr, U32 litLength, const BYTE *literals, U32 offset, U32 matchLength, const int ultra)
141 {
142 	/* offset */
143 	U32 price;
144 	BYTE const offCode = (BYTE)ZSTD_highbit32(offset + 1);
145 
146 	if (seqStorePtr->staticPrices)
147 		return ZSTD_getLiteralPrice(seqStorePtr, litLength, literals) + ZSTD_highbit32((U32)matchLength + 1) + 16 + offCode;
148 
149 	price = offCode + seqStorePtr->log2offCodeSum - ZSTD_highbit32(seqStorePtr->offCodeFreq[offCode] + 1);
150 	if (!ultra && offCode >= 20)
151 		price += (offCode - 19) * 2;
152 
153 	/* match Length */
154 	{
155 		const BYTE ML_deltaCode = 36;
156 		const BYTE mlCode = (matchLength > 127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
157 		price += ML_bits[mlCode] + seqStorePtr->log2matchLengthSum - ZSTD_highbit32(seqStorePtr->matchLengthFreq[mlCode] + 1);
158 	}
159 
160 	return price + ZSTD_getLiteralPrice(seqStorePtr, litLength, literals) + seqStorePtr->factor;
161 }
162 
ZSTD_updatePrice(seqStore_t * seqStorePtr,U32 litLength,const BYTE * literals,U32 offset,U32 matchLength)163 ZSTD_STATIC void ZSTD_updatePrice(seqStore_t *seqStorePtr, U32 litLength, const BYTE *literals, U32 offset, U32 matchLength)
164 {
165 	U32 u;
166 
167 	/* literals */
168 	seqStorePtr->litSum += litLength * ZSTD_LITFREQ_ADD;
169 	for (u = 0; u < litLength; u++)
170 		seqStorePtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
171 
172 	/* literal Length */
173 	{
174 		const BYTE LL_deltaCode = 19;
175 		const BYTE llCode = (litLength > 63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
176 		seqStorePtr->litLengthFreq[llCode]++;
177 		seqStorePtr->litLengthSum++;
178 	}
179 
180 	/* match offset */
181 	{
182 		BYTE const offCode = (BYTE)ZSTD_highbit32(offset + 1);
183 		seqStorePtr->offCodeSum++;
184 		seqStorePtr->offCodeFreq[offCode]++;
185 	}
186 
187 	/* match Length */
188 	{
189 		const BYTE ML_deltaCode = 36;
190 		const BYTE mlCode = (matchLength > 127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
191 		seqStorePtr->matchLengthFreq[mlCode]++;
192 		seqStorePtr->matchLengthSum++;
193 	}
194 
195 	ZSTD_setLog2Prices(seqStorePtr);
196 }
197 
198 #define SET_PRICE(pos, mlen_, offset_, litlen_, price_)           \
199 	{                                                         \
200 		while (last_pos < pos) {                          \
201 			opt[last_pos + 1].price = ZSTD_MAX_PRICE; \
202 			last_pos++;                               \
203 		}                                                 \
204 		opt[pos].mlen = mlen_;                            \
205 		opt[pos].off = offset_;                           \
206 		opt[pos].litlen = litlen_;                        \
207 		opt[pos].price = price_;                          \
208 	}
209 
210 /* Update hashTable3 up to ip (excluded)
211    Assumption : always within prefix (i.e. not within extDict) */
212 FORCE_INLINE
ZSTD_insertAndFindFirstIndexHash3(ZSTD_CCtx * zc,const BYTE * ip)213 U32 ZSTD_insertAndFindFirstIndexHash3(ZSTD_CCtx *zc, const BYTE *ip)
214 {
215 	U32 *const hashTable3 = zc->hashTable3;
216 	U32 const hashLog3 = zc->hashLog3;
217 	const BYTE *const base = zc->base;
218 	U32 idx = zc->nextToUpdate3;
219 	const U32 target = zc->nextToUpdate3 = (U32)(ip - base);
220 	const size_t hash3 = ZSTD_hash3Ptr(ip, hashLog3);
221 
222 	while (idx < target) {
223 		hashTable3[ZSTD_hash3Ptr(base + idx, hashLog3)] = idx;
224 		idx++;
225 	}
226 
227 	return hashTable3[hash3];
228 }
229 
230 /*-*************************************
231 *  Binary Tree search
232 ***************************************/
ZSTD_insertBtAndGetAllMatches(ZSTD_CCtx * zc,const BYTE * const ip,const BYTE * const iLimit,U32 nbCompares,const U32 mls,U32 extDict,ZSTD_match_t * matches,const U32 minMatchLen)233 static U32 ZSTD_insertBtAndGetAllMatches(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, U32 nbCompares, const U32 mls, U32 extDict,
234 					 ZSTD_match_t *matches, const U32 minMatchLen)
235 {
236 	const BYTE *const base = zc->base;
237 	const U32 curr = (U32)(ip - base);
238 	const U32 hashLog = zc->params.cParams.hashLog;
239 	const size_t h = ZSTD_hashPtr(ip, hashLog, mls);
240 	U32 *const hashTable = zc->hashTable;
241 	U32 matchIndex = hashTable[h];
242 	U32 *const bt = zc->chainTable;
243 	const U32 btLog = zc->params.cParams.chainLog - 1;
244 	const U32 btMask = (1U << btLog) - 1;
245 	size_t commonLengthSmaller = 0, commonLengthLarger = 0;
246 	const BYTE *const dictBase = zc->dictBase;
247 	const U32 dictLimit = zc->dictLimit;
248 	const BYTE *const dictEnd = dictBase + dictLimit;
249 	const BYTE *const prefixStart = base + dictLimit;
250 	const U32 btLow = btMask >= curr ? 0 : curr - btMask;
251 	const U32 windowLow = zc->lowLimit;
252 	U32 *smallerPtr = bt + 2 * (curr & btMask);
253 	U32 *largerPtr = bt + 2 * (curr & btMask) + 1;
254 	U32 matchEndIdx = curr + 8;
255 	U32 dummy32; /* to be nullified at the end */
256 	U32 mnum = 0;
257 
258 	const U32 minMatch = (mls == 3) ? 3 : 4;
259 	size_t bestLength = minMatchLen - 1;
260 
261 	if (minMatch == 3) { /* HC3 match finder */
262 		U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3(zc, ip);
263 		if (matchIndex3 > windowLow && (curr - matchIndex3 < (1 << 18))) {
264 			const BYTE *match;
265 			size_t currMl = 0;
266 			if ((!extDict) || matchIndex3 >= dictLimit) {
267 				match = base + matchIndex3;
268 				if (match[bestLength] == ip[bestLength])
269 					currMl = ZSTD_count(ip, match, iLimit);
270 			} else {
271 				match = dictBase + matchIndex3;
272 				if (ZSTD_readMINMATCH(match, MINMATCH) ==
273 				    ZSTD_readMINMATCH(ip, MINMATCH)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
274 					currMl = ZSTD_count_2segments(ip + MINMATCH, match + MINMATCH, iLimit, dictEnd, prefixStart) + MINMATCH;
275 			}
276 
277 			/* save best solution */
278 			if (currMl > bestLength) {
279 				bestLength = currMl;
280 				matches[mnum].off = ZSTD_REP_MOVE_OPT + curr - matchIndex3;
281 				matches[mnum].len = (U32)currMl;
282 				mnum++;
283 				if (currMl > ZSTD_OPT_NUM)
284 					goto update;
285 				if (ip + currMl == iLimit)
286 					goto update; /* best possible, and avoid read overflow*/
287 			}
288 		}
289 	}
290 
291 	hashTable[h] = curr; /* Update Hash Table */
292 
293 	while (nbCompares-- && (matchIndex > windowLow)) {
294 		U32 *nextPtr = bt + 2 * (matchIndex & btMask);
295 		size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
296 		const BYTE *match;
297 
298 		if ((!extDict) || (matchIndex + matchLength >= dictLimit)) {
299 			match = base + matchIndex;
300 			if (match[matchLength] == ip[matchLength]) {
301 				matchLength += ZSTD_count(ip + matchLength + 1, match + matchLength + 1, iLimit) + 1;
302 			}
303 		} else {
304 			match = dictBase + matchIndex;
305 			matchLength += ZSTD_count_2segments(ip + matchLength, match + matchLength, iLimit, dictEnd, prefixStart);
306 			if (matchIndex + matchLength >= dictLimit)
307 				match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
308 		}
309 
310 		if (matchLength > bestLength) {
311 			if (matchLength > matchEndIdx - matchIndex)
312 				matchEndIdx = matchIndex + (U32)matchLength;
313 			bestLength = matchLength;
314 			matches[mnum].off = ZSTD_REP_MOVE_OPT + curr - matchIndex;
315 			matches[mnum].len = (U32)matchLength;
316 			mnum++;
317 			if (matchLength > ZSTD_OPT_NUM)
318 				break;
319 			if (ip + matchLength == iLimit) /* equal : no way to know if inf or sup */
320 				break;			/* drop, to guarantee consistency (miss a little bit of compression) */
321 		}
322 
323 		if (match[matchLength] < ip[matchLength]) {
324 			/* match is smaller than curr */
325 			*smallerPtr = matchIndex;	  /* update smaller idx */
326 			commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
327 			if (matchIndex <= btLow) {
328 				smallerPtr = &dummy32;
329 				break;
330 			}			  /* beyond tree size, stop the search */
331 			smallerPtr = nextPtr + 1; /* new "smaller" => larger of match */
332 			matchIndex = nextPtr[1];  /* new matchIndex larger than previous (closer to curr) */
333 		} else {
334 			/* match is larger than curr */
335 			*largerPtr = matchIndex;
336 			commonLengthLarger = matchLength;
337 			if (matchIndex <= btLow) {
338 				largerPtr = &dummy32;
339 				break;
340 			} /* beyond tree size, stop the search */
341 			largerPtr = nextPtr;
342 			matchIndex = nextPtr[0];
343 		}
344 	}
345 
346 	*smallerPtr = *largerPtr = 0;
347 
348 update:
349 	zc->nextToUpdate = (matchEndIdx > curr + 8) ? matchEndIdx - 8 : curr + 1;
350 	return mnum;
351 }
352 
353 /** Tree updater, providing best match */
ZSTD_BtGetAllMatches(ZSTD_CCtx * zc,const BYTE * const ip,const BYTE * const iLimit,const U32 maxNbAttempts,const U32 mls,ZSTD_match_t * matches,const U32 minMatchLen)354 static U32 ZSTD_BtGetAllMatches(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, const U32 maxNbAttempts, const U32 mls, ZSTD_match_t *matches,
355 				const U32 minMatchLen)
356 {
357 	if (ip < zc->base + zc->nextToUpdate)
358 		return 0; /* skipped area */
359 	ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
360 	return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 0, matches, minMatchLen);
361 }
362 
ZSTD_BtGetAllMatches_selectMLS(ZSTD_CCtx * zc,const BYTE * ip,const BYTE * const iHighLimit,const U32 maxNbAttempts,const U32 matchLengthSearch,ZSTD_match_t * matches,const U32 minMatchLen)363 static U32 ZSTD_BtGetAllMatches_selectMLS(ZSTD_CCtx *zc, /* Index table will be updated */
364 					  const BYTE *ip, const BYTE *const iHighLimit, const U32 maxNbAttempts, const U32 matchLengthSearch,
365 					  ZSTD_match_t *matches, const U32 minMatchLen)
366 {
367 	switch (matchLengthSearch) {
368 	case 3: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 3, matches, minMatchLen);
369 	default:
370 	case 4: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minMatchLen);
371 	case 5: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minMatchLen);
372 	case 7:
373 	case 6: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minMatchLen);
374 	}
375 }
376 
377 /** Tree updater, providing best match */
ZSTD_BtGetAllMatches_extDict(ZSTD_CCtx * zc,const BYTE * const ip,const BYTE * const iLimit,const U32 maxNbAttempts,const U32 mls,ZSTD_match_t * matches,const U32 minMatchLen)378 static U32 ZSTD_BtGetAllMatches_extDict(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, const U32 maxNbAttempts, const U32 mls,
379 					ZSTD_match_t *matches, const U32 minMatchLen)
380 {
381 	if (ip < zc->base + zc->nextToUpdate)
382 		return 0; /* skipped area */
383 	ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
384 	return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 1, matches, minMatchLen);
385 }
386 
ZSTD_BtGetAllMatches_selectMLS_extDict(ZSTD_CCtx * zc,const BYTE * ip,const BYTE * const iHighLimit,const U32 maxNbAttempts,const U32 matchLengthSearch,ZSTD_match_t * matches,const U32 minMatchLen)387 static U32 ZSTD_BtGetAllMatches_selectMLS_extDict(ZSTD_CCtx *zc, /* Index table will be updated */
388 						  const BYTE *ip, const BYTE *const iHighLimit, const U32 maxNbAttempts, const U32 matchLengthSearch,
389 						  ZSTD_match_t *matches, const U32 minMatchLen)
390 {
391 	switch (matchLengthSearch) {
392 	case 3: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 3, matches, minMatchLen);
393 	default:
394 	case 4: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minMatchLen);
395 	case 5: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minMatchLen);
396 	case 7:
397 	case 6: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minMatchLen);
398 	}
399 }
400 
401 /*-*******************************
402 *  Optimal parser
403 *********************************/
404 FORCE_INLINE
ZSTD_compressBlock_opt_generic(ZSTD_CCtx * ctx,const void * src,size_t srcSize,const int ultra)405 void ZSTD_compressBlock_opt_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const int ultra)
406 {
407 	seqStore_t *seqStorePtr = &(ctx->seqStore);
408 	const BYTE *const istart = (const BYTE *)src;
409 	const BYTE *ip = istart;
410 	const BYTE *anchor = istart;
411 	const BYTE *const iend = istart + srcSize;
412 	const BYTE *const ilimit = iend - 8;
413 	const BYTE *const base = ctx->base;
414 	const BYTE *const prefixStart = base + ctx->dictLimit;
415 
416 	const U32 maxSearches = 1U << ctx->params.cParams.searchLog;
417 	const U32 sufficient_len = ctx->params.cParams.targetLength;
418 	const U32 mls = ctx->params.cParams.searchLength;
419 	const U32 minMatch = (ctx->params.cParams.searchLength == 3) ? 3 : 4;
420 
421 	ZSTD_optimal_t *opt = seqStorePtr->priceTable;
422 	ZSTD_match_t *matches = seqStorePtr->matchTable;
423 	const BYTE *inr;
424 	U32 offset, rep[ZSTD_REP_NUM];
425 
426 	/* init */
427 	ctx->nextToUpdate3 = ctx->nextToUpdate;
428 	ZSTD_rescaleFreqs(seqStorePtr, (const BYTE *)src, srcSize);
429 	ip += (ip == prefixStart);
430 	{
431 		U32 i;
432 		for (i = 0; i < ZSTD_REP_NUM; i++)
433 			rep[i] = ctx->rep[i];
434 	}
435 
436 	/* Match Loop */
437 	while (ip < ilimit) {
438 		U32 cur, match_num, last_pos, litlen, price;
439 		U32 u, mlen, best_mlen, best_off, litLength;
440 		memset(opt, 0, sizeof(ZSTD_optimal_t));
441 		last_pos = 0;
442 		litlen = (U32)(ip - anchor);
443 
444 		/* check repCode */
445 		{
446 			U32 i, last_i = ZSTD_REP_CHECK + (ip == anchor);
447 			for (i = (ip == anchor); i < last_i; i++) {
448 				const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : rep[i];
449 				if ((repCur > 0) && (repCur < (S32)(ip - prefixStart)) &&
450 				    (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repCur, minMatch))) {
451 					mlen = (U32)ZSTD_count(ip + minMatch, ip + minMatch - repCur, iend) + minMatch;
452 					if (mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
453 						best_mlen = mlen;
454 						best_off = i;
455 						cur = 0;
456 						last_pos = 1;
457 						goto _storeSequence;
458 					}
459 					best_off = i - (ip == anchor);
460 					do {
461 						price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
462 						if (mlen > last_pos || price < opt[mlen].price)
463 							SET_PRICE(mlen, mlen, i, litlen, price); /* note : macro modifies last_pos */
464 						mlen--;
465 					} while (mlen >= minMatch);
466 				}
467 			}
468 		}
469 
470 		match_num = ZSTD_BtGetAllMatches_selectMLS(ctx, ip, iend, maxSearches, mls, matches, minMatch);
471 
472 		if (!last_pos && !match_num) {
473 			ip++;
474 			continue;
475 		}
476 
477 		if (match_num && (matches[match_num - 1].len > sufficient_len || matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
478 			best_mlen = matches[match_num - 1].len;
479 			best_off = matches[match_num - 1].off;
480 			cur = 0;
481 			last_pos = 1;
482 			goto _storeSequence;
483 		}
484 
485 		/* set prices using matches at position = 0 */
486 		best_mlen = (last_pos) ? last_pos : minMatch;
487 		for (u = 0; u < match_num; u++) {
488 			mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
489 			best_mlen = matches[u].len;
490 			while (mlen <= best_mlen) {
491 				price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
492 				if (mlen > last_pos || price < opt[mlen].price)
493 					SET_PRICE(mlen, mlen, matches[u].off, litlen, price); /* note : macro modifies last_pos */
494 				mlen++;
495 			}
496 		}
497 
498 		if (last_pos < minMatch) {
499 			ip++;
500 			continue;
501 		}
502 
503 		/* initialize opt[0] */
504 		{
505 			U32 i;
506 			for (i = 0; i < ZSTD_REP_NUM; i++)
507 				opt[0].rep[i] = rep[i];
508 		}
509 		opt[0].mlen = 1;
510 		opt[0].litlen = litlen;
511 
512 		/* check further positions */
513 		for (cur = 1; cur <= last_pos; cur++) {
514 			inr = ip + cur;
515 
516 			if (opt[cur - 1].mlen == 1) {
517 				litlen = opt[cur - 1].litlen + 1;
518 				if (cur > litlen) {
519 					price = opt[cur - litlen].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - litlen);
520 				} else
521 					price = ZSTD_getLiteralPrice(seqStorePtr, litlen, anchor);
522 			} else {
523 				litlen = 1;
524 				price = opt[cur - 1].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - 1);
525 			}
526 
527 			if (cur > last_pos || price <= opt[cur].price)
528 				SET_PRICE(cur, 1, 0, litlen, price);
529 
530 			if (cur == last_pos)
531 				break;
532 
533 			if (inr > ilimit) /* last match must start at a minimum distance of 8 from oend */
534 				continue;
535 
536 			mlen = opt[cur].mlen;
537 			if (opt[cur].off > ZSTD_REP_MOVE_OPT) {
538 				opt[cur].rep[2] = opt[cur - mlen].rep[1];
539 				opt[cur].rep[1] = opt[cur - mlen].rep[0];
540 				opt[cur].rep[0] = opt[cur].off - ZSTD_REP_MOVE_OPT;
541 			} else {
542 				opt[cur].rep[2] = (opt[cur].off > 1) ? opt[cur - mlen].rep[1] : opt[cur - mlen].rep[2];
543 				opt[cur].rep[1] = (opt[cur].off > 0) ? opt[cur - mlen].rep[0] : opt[cur - mlen].rep[1];
544 				opt[cur].rep[0] =
545 				    ((opt[cur].off == ZSTD_REP_MOVE_OPT) && (mlen != 1)) ? (opt[cur - mlen].rep[0] - 1) : (opt[cur - mlen].rep[opt[cur].off]);
546 			}
547 
548 			best_mlen = minMatch;
549 			{
550 				U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
551 				for (i = (opt[cur].mlen != 1); i < last_i; i++) { /* check rep */
552 					const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (opt[cur].rep[0] - 1) : opt[cur].rep[i];
553 					if ((repCur > 0) && (repCur < (S32)(inr - prefixStart)) &&
554 					    (ZSTD_readMINMATCH(inr, minMatch) == ZSTD_readMINMATCH(inr - repCur, minMatch))) {
555 						mlen = (U32)ZSTD_count(inr + minMatch, inr + minMatch - repCur, iend) + minMatch;
556 
557 						if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
558 							best_mlen = mlen;
559 							best_off = i;
560 							last_pos = cur + 1;
561 							goto _storeSequence;
562 						}
563 
564 						best_off = i - (opt[cur].mlen != 1);
565 						if (mlen > best_mlen)
566 							best_mlen = mlen;
567 
568 						do {
569 							if (opt[cur].mlen == 1) {
570 								litlen = opt[cur].litlen;
571 								if (cur > litlen) {
572 									price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr - litlen,
573 															best_off, mlen - MINMATCH, ultra);
574 								} else
575 									price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
576 							} else {
577 								litlen = 0;
578 								price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
579 							}
580 
581 							if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
582 								SET_PRICE(cur + mlen, mlen, i, litlen, price);
583 							mlen--;
584 						} while (mlen >= minMatch);
585 					}
586 				}
587 			}
588 
589 			match_num = ZSTD_BtGetAllMatches_selectMLS(ctx, inr, iend, maxSearches, mls, matches, best_mlen);
590 
591 			if (match_num > 0 && (matches[match_num - 1].len > sufficient_len || cur + matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
592 				best_mlen = matches[match_num - 1].len;
593 				best_off = matches[match_num - 1].off;
594 				last_pos = cur + 1;
595 				goto _storeSequence;
596 			}
597 
598 			/* set prices using matches at position = cur */
599 			for (u = 0; u < match_num; u++) {
600 				mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
601 				best_mlen = matches[u].len;
602 
603 				while (mlen <= best_mlen) {
604 					if (opt[cur].mlen == 1) {
605 						litlen = opt[cur].litlen;
606 						if (cur > litlen)
607 							price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, ip + cur - litlen,
608 													matches[u].off - 1, mlen - MINMATCH, ultra);
609 						else
610 							price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
611 					} else {
612 						litlen = 0;
613 						price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, matches[u].off - 1, mlen - MINMATCH, ultra);
614 					}
615 
616 					if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
617 						SET_PRICE(cur + mlen, mlen, matches[u].off, litlen, price);
618 
619 					mlen++;
620 				}
621 			}
622 		}
623 
624 		best_mlen = opt[last_pos].mlen;
625 		best_off = opt[last_pos].off;
626 		cur = last_pos - best_mlen;
627 
628 	/* store sequence */
629 _storeSequence: /* cur, last_pos, best_mlen, best_off have to be set */
630 		opt[0].mlen = 1;
631 
632 		while (1) {
633 			mlen = opt[cur].mlen;
634 			offset = opt[cur].off;
635 			opt[cur].mlen = best_mlen;
636 			opt[cur].off = best_off;
637 			best_mlen = mlen;
638 			best_off = offset;
639 			if (mlen > cur)
640 				break;
641 			cur -= mlen;
642 		}
643 
644 		for (u = 0; u <= last_pos;) {
645 			u += opt[u].mlen;
646 		}
647 
648 		for (cur = 0; cur < last_pos;) {
649 			mlen = opt[cur].mlen;
650 			if (mlen == 1) {
651 				ip++;
652 				cur++;
653 				continue;
654 			}
655 			offset = opt[cur].off;
656 			cur += mlen;
657 			litLength = (U32)(ip - anchor);
658 
659 			if (offset > ZSTD_REP_MOVE_OPT) {
660 				rep[2] = rep[1];
661 				rep[1] = rep[0];
662 				rep[0] = offset - ZSTD_REP_MOVE_OPT;
663 				offset--;
664 			} else {
665 				if (offset != 0) {
666 					best_off = (offset == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : (rep[offset]);
667 					if (offset != 1)
668 						rep[2] = rep[1];
669 					rep[1] = rep[0];
670 					rep[0] = best_off;
671 				}
672 				if (litLength == 0)
673 					offset--;
674 			}
675 
676 			ZSTD_updatePrice(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
677 			ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
678 			anchor = ip = ip + mlen;
679 		}
680 	} /* for (cur=0; cur < last_pos; ) */
681 
682 	/* Save reps for next block */
683 	{
684 		int i;
685 		for (i = 0; i < ZSTD_REP_NUM; i++)
686 			ctx->repToConfirm[i] = rep[i];
687 	}
688 
689 	/* Last Literals */
690 	{
691 		size_t const lastLLSize = iend - anchor;
692 		memcpy(seqStorePtr->lit, anchor, lastLLSize);
693 		seqStorePtr->lit += lastLLSize;
694 	}
695 }
696 
697 FORCE_INLINE
ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx * ctx,const void * src,size_t srcSize,const int ultra)698 void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const int ultra)
699 {
700 	seqStore_t *seqStorePtr = &(ctx->seqStore);
701 	const BYTE *const istart = (const BYTE *)src;
702 	const BYTE *ip = istart;
703 	const BYTE *anchor = istart;
704 	const BYTE *const iend = istart + srcSize;
705 	const BYTE *const ilimit = iend - 8;
706 	const BYTE *const base = ctx->base;
707 	const U32 lowestIndex = ctx->lowLimit;
708 	const U32 dictLimit = ctx->dictLimit;
709 	const BYTE *const prefixStart = base + dictLimit;
710 	const BYTE *const dictBase = ctx->dictBase;
711 	const BYTE *const dictEnd = dictBase + dictLimit;
712 
713 	const U32 maxSearches = 1U << ctx->params.cParams.searchLog;
714 	const U32 sufficient_len = ctx->params.cParams.targetLength;
715 	const U32 mls = ctx->params.cParams.searchLength;
716 	const U32 minMatch = (ctx->params.cParams.searchLength == 3) ? 3 : 4;
717 
718 	ZSTD_optimal_t *opt = seqStorePtr->priceTable;
719 	ZSTD_match_t *matches = seqStorePtr->matchTable;
720 	const BYTE *inr;
721 
722 	/* init */
723 	U32 offset, rep[ZSTD_REP_NUM];
724 	{
725 		U32 i;
726 		for (i = 0; i < ZSTD_REP_NUM; i++)
727 			rep[i] = ctx->rep[i];
728 	}
729 
730 	ctx->nextToUpdate3 = ctx->nextToUpdate;
731 	ZSTD_rescaleFreqs(seqStorePtr, (const BYTE *)src, srcSize);
732 	ip += (ip == prefixStart);
733 
734 	/* Match Loop */
735 	while (ip < ilimit) {
736 		U32 cur, match_num, last_pos, litlen, price;
737 		U32 u, mlen, best_mlen, best_off, litLength;
738 		U32 curr = (U32)(ip - base);
739 		memset(opt, 0, sizeof(ZSTD_optimal_t));
740 		last_pos = 0;
741 		opt[0].litlen = (U32)(ip - anchor);
742 
743 		/* check repCode */
744 		{
745 			U32 i, last_i = ZSTD_REP_CHECK + (ip == anchor);
746 			for (i = (ip == anchor); i < last_i; i++) {
747 				const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : rep[i];
748 				const U32 repIndex = (U32)(curr - repCur);
749 				const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
750 				const BYTE *const repMatch = repBase + repIndex;
751 				if ((repCur > 0 && repCur <= (S32)curr) &&
752 				    (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
753 				    && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch))) {
754 					/* repcode detected we should take it */
755 					const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
756 					mlen = (U32)ZSTD_count_2segments(ip + minMatch, repMatch + minMatch, iend, repEnd, prefixStart) + minMatch;
757 
758 					if (mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
759 						best_mlen = mlen;
760 						best_off = i;
761 						cur = 0;
762 						last_pos = 1;
763 						goto _storeSequence;
764 					}
765 
766 					best_off = i - (ip == anchor);
767 					litlen = opt[0].litlen;
768 					do {
769 						price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
770 						if (mlen > last_pos || price < opt[mlen].price)
771 							SET_PRICE(mlen, mlen, i, litlen, price); /* note : macro modifies last_pos */
772 						mlen--;
773 					} while (mlen >= minMatch);
774 				}
775 			}
776 		}
777 
778 		match_num = ZSTD_BtGetAllMatches_selectMLS_extDict(ctx, ip, iend, maxSearches, mls, matches, minMatch); /* first search (depth 0) */
779 
780 		if (!last_pos && !match_num) {
781 			ip++;
782 			continue;
783 		}
784 
785 		{
786 			U32 i;
787 			for (i = 0; i < ZSTD_REP_NUM; i++)
788 				opt[0].rep[i] = rep[i];
789 		}
790 		opt[0].mlen = 1;
791 
792 		if (match_num && (matches[match_num - 1].len > sufficient_len || matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
793 			best_mlen = matches[match_num - 1].len;
794 			best_off = matches[match_num - 1].off;
795 			cur = 0;
796 			last_pos = 1;
797 			goto _storeSequence;
798 		}
799 
800 		best_mlen = (last_pos) ? last_pos : minMatch;
801 
802 		/* set prices using matches at position = 0 */
803 		for (u = 0; u < match_num; u++) {
804 			mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
805 			best_mlen = matches[u].len;
806 			litlen = opt[0].litlen;
807 			while (mlen <= best_mlen) {
808 				price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
809 				if (mlen > last_pos || price < opt[mlen].price)
810 					SET_PRICE(mlen, mlen, matches[u].off, litlen, price);
811 				mlen++;
812 			}
813 		}
814 
815 		if (last_pos < minMatch) {
816 			ip++;
817 			continue;
818 		}
819 
820 		/* check further positions */
821 		for (cur = 1; cur <= last_pos; cur++) {
822 			inr = ip + cur;
823 
824 			if (opt[cur - 1].mlen == 1) {
825 				litlen = opt[cur - 1].litlen + 1;
826 				if (cur > litlen) {
827 					price = opt[cur - litlen].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - litlen);
828 				} else
829 					price = ZSTD_getLiteralPrice(seqStorePtr, litlen, anchor);
830 			} else {
831 				litlen = 1;
832 				price = opt[cur - 1].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - 1);
833 			}
834 
835 			if (cur > last_pos || price <= opt[cur].price)
836 				SET_PRICE(cur, 1, 0, litlen, price);
837 
838 			if (cur == last_pos)
839 				break;
840 
841 			if (inr > ilimit) /* last match must start at a minimum distance of 8 from oend */
842 				continue;
843 
844 			mlen = opt[cur].mlen;
845 			if (opt[cur].off > ZSTD_REP_MOVE_OPT) {
846 				opt[cur].rep[2] = opt[cur - mlen].rep[1];
847 				opt[cur].rep[1] = opt[cur - mlen].rep[0];
848 				opt[cur].rep[0] = opt[cur].off - ZSTD_REP_MOVE_OPT;
849 			} else {
850 				opt[cur].rep[2] = (opt[cur].off > 1) ? opt[cur - mlen].rep[1] : opt[cur - mlen].rep[2];
851 				opt[cur].rep[1] = (opt[cur].off > 0) ? opt[cur - mlen].rep[0] : opt[cur - mlen].rep[1];
852 				opt[cur].rep[0] =
853 				    ((opt[cur].off == ZSTD_REP_MOVE_OPT) && (mlen != 1)) ? (opt[cur - mlen].rep[0] - 1) : (opt[cur - mlen].rep[opt[cur].off]);
854 			}
855 
856 			best_mlen = minMatch;
857 			{
858 				U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
859 				for (i = (mlen != 1); i < last_i; i++) {
860 					const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (opt[cur].rep[0] - 1) : opt[cur].rep[i];
861 					const U32 repIndex = (U32)(curr + cur - repCur);
862 					const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
863 					const BYTE *const repMatch = repBase + repIndex;
864 					if ((repCur > 0 && repCur <= (S32)(curr + cur)) &&
865 					    (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
866 					    && (ZSTD_readMINMATCH(inr, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch))) {
867 						/* repcode detected */
868 						const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
869 						mlen = (U32)ZSTD_count_2segments(inr + minMatch, repMatch + minMatch, iend, repEnd, prefixStart) + minMatch;
870 
871 						if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
872 							best_mlen = mlen;
873 							best_off = i;
874 							last_pos = cur + 1;
875 							goto _storeSequence;
876 						}
877 
878 						best_off = i - (opt[cur].mlen != 1);
879 						if (mlen > best_mlen)
880 							best_mlen = mlen;
881 
882 						do {
883 							if (opt[cur].mlen == 1) {
884 								litlen = opt[cur].litlen;
885 								if (cur > litlen) {
886 									price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr - litlen,
887 															best_off, mlen - MINMATCH, ultra);
888 								} else
889 									price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
890 							} else {
891 								litlen = 0;
892 								price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
893 							}
894 
895 							if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
896 								SET_PRICE(cur + mlen, mlen, i, litlen, price);
897 							mlen--;
898 						} while (mlen >= minMatch);
899 					}
900 				}
901 			}
902 
903 			match_num = ZSTD_BtGetAllMatches_selectMLS_extDict(ctx, inr, iend, maxSearches, mls, matches, minMatch);
904 
905 			if (match_num > 0 && (matches[match_num - 1].len > sufficient_len || cur + matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
906 				best_mlen = matches[match_num - 1].len;
907 				best_off = matches[match_num - 1].off;
908 				last_pos = cur + 1;
909 				goto _storeSequence;
910 			}
911 
912 			/* set prices using matches at position = cur */
913 			for (u = 0; u < match_num; u++) {
914 				mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
915 				best_mlen = matches[u].len;
916 
917 				while (mlen <= best_mlen) {
918 					if (opt[cur].mlen == 1) {
919 						litlen = opt[cur].litlen;
920 						if (cur > litlen)
921 							price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, ip + cur - litlen,
922 													matches[u].off - 1, mlen - MINMATCH, ultra);
923 						else
924 							price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
925 					} else {
926 						litlen = 0;
927 						price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, matches[u].off - 1, mlen - MINMATCH, ultra);
928 					}
929 
930 					if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
931 						SET_PRICE(cur + mlen, mlen, matches[u].off, litlen, price);
932 
933 					mlen++;
934 				}
935 			}
936 		} /* for (cur = 1; cur <= last_pos; cur++) */
937 
938 		best_mlen = opt[last_pos].mlen;
939 		best_off = opt[last_pos].off;
940 		cur = last_pos - best_mlen;
941 
942 	/* store sequence */
943 _storeSequence: /* cur, last_pos, best_mlen, best_off have to be set */
944 		opt[0].mlen = 1;
945 
946 		while (1) {
947 			mlen = opt[cur].mlen;
948 			offset = opt[cur].off;
949 			opt[cur].mlen = best_mlen;
950 			opt[cur].off = best_off;
951 			best_mlen = mlen;
952 			best_off = offset;
953 			if (mlen > cur)
954 				break;
955 			cur -= mlen;
956 		}
957 
958 		for (u = 0; u <= last_pos;) {
959 			u += opt[u].mlen;
960 		}
961 
962 		for (cur = 0; cur < last_pos;) {
963 			mlen = opt[cur].mlen;
964 			if (mlen == 1) {
965 				ip++;
966 				cur++;
967 				continue;
968 			}
969 			offset = opt[cur].off;
970 			cur += mlen;
971 			litLength = (U32)(ip - anchor);
972 
973 			if (offset > ZSTD_REP_MOVE_OPT) {
974 				rep[2] = rep[1];
975 				rep[1] = rep[0];
976 				rep[0] = offset - ZSTD_REP_MOVE_OPT;
977 				offset--;
978 			} else {
979 				if (offset != 0) {
980 					best_off = (offset == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : (rep[offset]);
981 					if (offset != 1)
982 						rep[2] = rep[1];
983 					rep[1] = rep[0];
984 					rep[0] = best_off;
985 				}
986 
987 				if (litLength == 0)
988 					offset--;
989 			}
990 
991 			ZSTD_updatePrice(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
992 			ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
993 			anchor = ip = ip + mlen;
994 		}
995 	} /* for (cur=0; cur < last_pos; ) */
996 
997 	/* Save reps for next block */
998 	{
999 		int i;
1000 		for (i = 0; i < ZSTD_REP_NUM; i++)
1001 			ctx->repToConfirm[i] = rep[i];
1002 	}
1003 
1004 	/* Last Literals */
1005 	{
1006 		size_t lastLLSize = iend - anchor;
1007 		memcpy(seqStorePtr->lit, anchor, lastLLSize);
1008 		seqStorePtr->lit += lastLLSize;
1009 	}
1010 }
1011 
1012 #endif /* ZSTD_OPT_H_91842398743 */
1013