zstd_opt.h

/**
 * Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of https://github.com/facebook/zstd.
 * An additional grant of patent rights can be found in the PATENTS file in the
 * same directory.
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation. This program is dual-licensed; you may select
 * either version 2 of the GNU General Public License ("GPL") or BSD license
 * ("BSD").
 */

/* Note : this file is intended to be included within zstd_compress.c */

#ifndef ZSTD_OPT_H_91842398743
#define ZSTD_OPT_H_91842398743

#define ZSTD_LITFREQ_ADD 2
#define ZSTD_FREQ_DIV 4
#define ZSTD_MAX_PRICE (1 << 30)

/*-*************************************
*  Price functions for optimal parser
***************************************/
FORCE_INLINE void ZSTD_setLog2Prices(seqStore_t *ssPtr)
{
	ssPtr->log2matchLengthSum = ZSTD_highbit32(ssPtr->matchLengthSum + 1);
	ssPtr->log2litLengthSum = ZSTD_highbit32(ssPtr->litLengthSum + 1);
	ssPtr->log2litSum = ZSTD_highbit32(ssPtr->litSum + 1);
	ssPtr->log2offCodeSum = ZSTD_highbit32(ssPtr->offCodeSum + 1);
	ssPtr->factor = 1 + ((ssPtr->litSum >> 5) / ssPtr->litLengthSum) + ((ssPtr->litSum << 1) / (ssPtr->litSum + ssPtr->matchSum));
}

ZSTD_STATIC void ZSTD_rescaleFreqs(seqStore_t *ssPtr, const BYTE *src, size_t srcSize)
{
	unsigned u;

	ssPtr->cachedLiterals = NULL;
	ssPtr->cachedPrice = ssPtr->cachedLitLength = 0;
	ssPtr->staticPrices = 0;

	if (ssPtr->litLengthSum == 0) {
		if (srcSize <= 1024)
			ssPtr->staticPrices = 1;

		for (u = 0; u <= MaxLit; u++)
			ssPtr->litFreq[u] = 0;
		for (u = 0; u < srcSize; u++)
			ssPtr->litFreq[src[u]]++;

		ssPtr->litSum = 0;
		ssPtr->litLengthSum = MaxLL + 1;
		ssPtr->matchLengthSum = MaxML + 1;
		ssPtr->offCodeSum = (MaxOff + 1);
		ssPtr->matchSum = (ZSTD_LITFREQ_ADD << Litbits);

		for (u = 0; u <= MaxLit; u++) {
			ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u] >> ZSTD_FREQ_DIV);
			ssPtr->litSum += ssPtr->litFreq[u];
		}
		for (u = 0; u <= MaxLL; u++)
			ssPtr->litLengthFreq[u] = 1;
		for (u = 0; u <= MaxML; u++)
			ssPtr->matchLengthFreq[u] = 1;
		for (u = 0; u <= MaxOff; u++)
			ssPtr->offCodeFreq[u] = 1;
	} else {
		ssPtr->matchLengthSum = 0;
		ssPtr->litLengthSum = 0;
		ssPtr->offCodeSum = 0;
		ssPtr->matchSum = 0;
		ssPtr->litSum = 0;

		for (u = 0; u <= MaxLit; u++) {
			ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u] >> (ZSTD_FREQ_DIV + 1));
			ssPtr->litSum += ssPtr->litFreq[u];
		}
		for (u = 0; u <= MaxLL; u++) {
			ssPtr->litLengthFreq[u] = 1 + (ssPtr->litLengthFreq[u] >> (ZSTD_FREQ_DIV + 1));
			ssPtr->litLengthSum += ssPtr->litLengthFreq[u];
		}
		for (u = 0; u <= MaxML; u++) {
			ssPtr->matchLengthFreq[u] = 1 + (ssPtr->matchLengthFreq[u] >> ZSTD_FREQ_DIV);
			ssPtr->matchLengthSum += ssPtr->matchLengthFreq[u];
			ssPtr->matchSum += ssPtr->matchLengthFreq[u] * (u + 3);
		}
		ssPtr->matchSum *= ZSTD_LITFREQ_ADD;
		for (u = 0; u <= MaxOff; u++) {
			ssPtr->offCodeFreq[u] = 1 + (ssPtr->offCodeFreq[u] >> ZSTD_FREQ_DIV);
			ssPtr->offCodeSum += ssPtr->offCodeFreq[u];
		}
	}

	ZSTD_setLog2Prices(ssPtr);
}

FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t *ssPtr, U32 litLength, const BYTE *literals)
{
	U32 price, u;

	if (ssPtr->staticPrices)
		return ZSTD_highbit32((U32)litLength + 1) + (litLength * 6);

	if (litLength == 0)
		return ssPtr->log2litLengthSum - ZSTD_highbit32(ssPtr->litLengthFreq[0] + 1);

	/* literals */
	if (ssPtr->cachedLiterals == literals) {
		U32 const additional = litLength - ssPtr->cachedLitLength;
		const BYTE *literals2 = ssPtr->cachedLiterals + ssPtr->cachedLitLength;
		price = ssPtr->cachedPrice + additional * ssPtr->log2litSum;
		for (u = 0; u < additional; u++)
			price -= ZSTD_highbit32(ssPtr->litFreq[literals2[u]] + 1);
		ssPtr->cachedPrice = price;
		ssPtr->cachedLitLength = litLength;
	} else {
		price = litLength * ssPtr->log2litSum;
		for (u = 0; u < litLength; u++)
			price -= ZSTD_highbit32(ssPtr->litFreq[literals[u]] + 1);

		if (litLength >= 12) {
			ssPtr->cachedLiterals = literals;
			ssPtr->cachedPrice = price;
			ssPtr->cachedLitLength = litLength;
		}
	}

	/* literal Length */
	{
		const BYTE LL_deltaCode = 19;
		const BYTE llCode = (litLength > 63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
		price += LL_bits[llCode] + ssPtr->log2litLengthSum - ZSTD_highbit32(ssPtr->litLengthFreq[llCode] + 1);
	}

	return price;
}

FORCE_INLINE U32 ZSTD_getPrice(seqStore_t *seqStorePtr, U32 litLength, const BYTE *literals, U32 offset, U32 matchLength, const int ultra)
{
	/* offset */
	U32 price;
	BYTE const offCode = (BYTE)ZSTD_highbit32(offset + 1);

	if (seqStorePtr->staticPrices)
		return ZSTD_getLiteralPrice(seqStorePtr, litLength, literals) + ZSTD_highbit32((U32)matchLength + 1) + 16 + offCode;

	price = offCode + seqStorePtr->log2offCodeSum - ZSTD_highbit32(seqStorePtr->offCodeFreq[offCode] + 1);
	if (!ultra && offCode >= 20)
		price += (offCode - 19) * 2;

	/* match Length */
	{
		const BYTE ML_deltaCode = 36;
		const BYTE mlCode = (matchLength > 127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
		price += ML_bits[mlCode] + seqStorePtr->log2matchLengthSum - ZSTD_highbit32(seqStorePtr->matchLengthFreq[mlCode] + 1);
	}

	return price + ZSTD_getLiteralPrice(seqStorePtr, litLength, literals) + seqStorePtr->factor;
}

ZSTD_STATIC void ZSTD_updatePrice(seqStore_t *seqStorePtr, U32 litLength, const BYTE *literals, U32 offset, U32 matchLength)
{
	U32 u;

	/* literals */
	seqStorePtr->litSum += litLength * ZSTD_LITFREQ_ADD;
	for (u = 0; u < litLength; u++)
		seqStorePtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;

	/* literal Length */
	{
		const BYTE LL_deltaCode = 19;
		const BYTE llCode = (litLength > 63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
		seqStorePtr->litLengthFreq[llCode]++;
		seqStorePtr->litLengthSum++;
	}

	/* match offset */
	{
		BYTE const offCode = (BYTE)ZSTD_highbit32(offset + 1);
		seqStorePtr->offCodeSum++;
		seqStorePtr->offCodeFreq[offCode]++;
	}

	/* match Length */
	{
		const BYTE ML_deltaCode = 36;
		const BYTE mlCode = (matchLength > 127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
		seqStorePtr->matchLengthFreq[mlCode]++;
		seqStorePtr->matchLengthSum++;
	}

	ZSTD_setLog2Prices(seqStorePtr);
}

#define SET_PRICE(pos, mlen_, offset_, litlen_, price_)           \
	{                                                         \
		while (last_pos < pos) {                          \
			opt[last_pos + 1].price = ZSTD_MAX_PRICE; \
			last_pos++;                               \
		}                                                 \
		opt[pos].mlen = mlen_;                            \
		opt[pos].off = offset_;                           \
		opt[pos].litlen = litlen_;                        \
		opt[pos].price = price_;                          \
	}

/* Update hashTable3 up to ip (excluded)
   Assumption : always within prefix (i.e. not within extDict) */
FORCE_INLINE
U32 ZSTD_insertAndFindFirstIndexHash3(ZSTD_CCtx *zc, const BYTE *ip)
{
	U32 *const hashTable3 = zc->hashTable3;
	U32 const hashLog3 = zc->hashLog3;
	const BYTE *const base = zc->base;
	U32 idx = zc->nextToUpdate3;
	const U32 target = zc->nextToUpdate3 = (U32)(ip - base);
	const size_t hash3 = ZSTD_hash3Ptr(ip, hashLog3);

	while (idx < target) {
		hashTable3[ZSTD_hash3Ptr(base + idx, hashLog3)] = idx;
		idx++;
	}

	return hashTable3[hash3];
}

/*-*************************************
*  Binary Tree search
***************************************/
static U32 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)
{
	const BYTE *const base = zc->base;
	const U32 curr = (U32)(ip - base);
	const U32 hashLog = zc->params.cParams.hashLog;
	const size_t h = ZSTD_hashPtr(ip, hashLog, mls);
	U32 *const hashTable = zc->hashTable;
	U32 matchIndex = hashTable[h];
	U32 *const bt = zc->chainTable;
	const U32 btLog = zc->params.cParams.chainLog - 1;
	const U32 btMask = (1U << btLog) - 1;
	size_t commonLengthSmaller = 0, commonLengthLarger = 0;
	const BYTE *const dictBase = zc->dictBase;
	const U32 dictLimit = zc->dictLimit;
	const BYTE *const dictEnd = dictBase + dictLimit;
	const BYTE *const prefixStart = base + dictLimit;
	const U32 btLow = btMask >= curr ? 0 : curr - btMask;
	const U32 windowLow = zc->lowLimit;
	U32 *smallerPtr = bt + 2 * (curr & btMask);
	U32 *largerPtr = bt + 2 * (curr & btMask) + 1;
	U32 matchEndIdx = curr + 8;
	U32 dummy32; /* to be nullified at the end */
	U32 mnum = 0;

	const U32 minMatch = (mls == 3) ? 3 : 4;
	size_t bestLength = minMatchLen - 1;

	if (minMatch == 3) { /* HC3 match finder */
		U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3(zc, ip);
		if (matchIndex3 > windowLow && (curr - matchIndex3 < (1 << 18))) {
			const BYTE *match;
			size_t currMl = 0;
			if ((!extDict) || matchIndex3 >= dictLimit) {
				match = base + matchIndex3;
				if (match[bestLength] == ip[bestLength])
					currMl = ZSTD_count(ip, match, iLimit);
			} else {
				match = dictBase + matchIndex3;
				if (ZSTD_readMINMATCH(match, MINMATCH) ==
				    ZSTD_readMINMATCH(ip, MINMATCH)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
					currMl = ZSTD_count_2segments(ip + MINMATCH, match + MINMATCH, iLimit, dictEnd, prefixStart) + MINMATCH;
			}

			/* save best solution */
			if (currMl > bestLength) {
				bestLength = currMl;
				matches[mnum].off = ZSTD_REP_MOVE_OPT + curr - matchIndex3;
				matches[mnum].len = (U32)currMl;
				mnum++;
				if (currMl > ZSTD_OPT_NUM)
					goto update;
				if (ip + currMl == iLimit)
					goto update; /* best possible, and avoid read overflow*/
			}
		}
	}

	hashTable[h] = curr; /* Update Hash Table */

	while (nbCompares-- && (matchIndex > windowLow)) {
		U32 *nextPtr = bt + 2 * (matchIndex & btMask);
		size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
		const BYTE *match;

		if ((!extDict) || (matchIndex + matchLength >= dictLimit)) {
			match = base + matchIndex;
			if (match[matchLength] == ip[matchLength]) {
				matchLength += ZSTD_count(ip + matchLength + 1, match + matchLength + 1, iLimit) + 1;
			}
		} else {
			match = dictBase + matchIndex;
			matchLength += ZSTD_count_2segments(ip + matchLength, match + matchLength, iLimit, dictEnd, prefixStart);
			if (matchIndex + matchLength >= dictLimit)
				match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
		}

		if (matchLength > bestLength) {
			if (matchLength > matchEndIdx - matchIndex)
				matchEndIdx = matchIndex + (U32)matchLength;
			bestLength = matchLength;
			matches[mnum].off = ZSTD_REP_MOVE_OPT + curr - matchIndex;
			matches[mnum].len = (U32)matchLength;
			mnum++;
			if (matchLength > ZSTD_OPT_NUM)
				break;
			if (ip + matchLength == iLimit) /* equal : no way to know if inf or sup */
				break;			/* drop, to guarantee consistency (miss a little bit of compression) */
		}

		if (match[matchLength] < ip[matchLength]) {
			/* match is smaller than curr */
			*smallerPtr = matchIndex;	  /* update smaller idx */
			commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
			if (matchIndex <= btLow) {
				smallerPtr = &dummy32;
				break;
			}			  /* beyond tree size, stop the search */
			smallerPtr = nextPtr + 1; /* new "smaller" => larger of match */
			matchIndex = nextPtr[1];  /* new matchIndex larger than previous (closer to curr) */
		} else {
			/* match is larger than curr */
			*largerPtr = matchIndex;
			commonLengthLarger = matchLength;
			if (matchIndex <= btLow) {
				largerPtr = &dummy32;
				break;
			} /* beyond tree size, stop the search */
			largerPtr = nextPtr;
			matchIndex = nextPtr[0];
		}
	}

	*smallerPtr = *largerPtr = 0;

update:
	zc->nextToUpdate = (matchEndIdx > curr + 8) ? matchEndIdx - 8 : curr + 1;
	return mnum;
}

/** Tree updater, providing best match */
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,
				const U32 minMatchLen)
{
	if (ip < zc->base + zc->nextToUpdate)
		return 0; /* skipped area */
	ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
	return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 0, matches, minMatchLen);
}

static U32 ZSTD_BtGetAllMatches_selectMLS(ZSTD_CCtx *zc, /* Index table will be updated */
					  const BYTE *ip, const BYTE *const iHighLimit, const U32 maxNbAttempts, const U32 matchLengthSearch,
					  ZSTD_match_t *matches, const U32 minMatchLen)
{
	switch (matchLengthSearch) {
	case 3: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 3, matches, minMatchLen);
	default:
	case 4: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minMatchLen);
	case 5: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minMatchLen);
	case 7:
	case 6: return ZSTD_BtGetAllMatches(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minMatchLen);
	}
}

/** Tree updater, providing best match */
static U32 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)
{
	if (ip < zc->base + zc->nextToUpdate)
		return 0; /* skipped area */
	ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
	return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 1, matches, minMatchLen);
}

static U32 ZSTD_BtGetAllMatches_selectMLS_extDict(ZSTD_CCtx *zc, /* Index table will be updated */
						  const BYTE *ip, const BYTE *const iHighLimit, const U32 maxNbAttempts, const U32 matchLengthSearch,
						  ZSTD_match_t *matches, const U32 minMatchLen)
{
	switch (matchLengthSearch) {
	case 3: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 3, matches, minMatchLen);
	default:
	case 4: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minMatchLen);
	case 5: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minMatchLen);
	case 7:
	case 6: return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minMatchLen);
	}
}

/*-*******************************
*  Optimal parser
*********************************/
FORCE_INLINE
void ZSTD_compressBlock_opt_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const int ultra)
{
	seqStore_t *seqStorePtr = &(ctx->seqStore);
	const BYTE *const istart = (const BYTE *)src;
	const BYTE *ip = istart;
	const BYTE *anchor = istart;
	const BYTE *const iend = istart + srcSize;
	const BYTE *const ilimit = iend - 8;
	const BYTE *const base = ctx->base;
	const BYTE *const prefixStart = base + ctx->dictLimit;

	const U32 maxSearches = 1U << ctx->params.cParams.searchLog;
	const U32 sufficient_len = ctx->params.cParams.targetLength;
	const U32 mls = ctx->params.cParams.searchLength;
	const U32 minMatch = (ctx->params.cParams.searchLength == 3) ? 3 : 4;

	ZSTD_optimal_t *opt = seqStorePtr->priceTable;
	ZSTD_match_t *matches = seqStorePtr->matchTable;
	const BYTE *inr;
	U32 offset, rep[ZSTD_REP_NUM];

	/* init */
	ctx->nextToUpdate3 = ctx->nextToUpdate;
	ZSTD_rescaleFreqs(seqStorePtr, (const BYTE *)src, srcSize);
	ip += (ip == prefixStart);
	{
		U32 i;
		for (i = 0; i < ZSTD_REP_NUM; i++)
			rep[i] = ctx->rep[i];
	}

	/* Match Loop */
	while (ip < ilimit) {
		U32 cur, match_num, last_pos, litlen, price;
		U32 u, mlen, best_mlen, best_off, litLength;
		memset(opt, 0, sizeof(ZSTD_optimal_t));
		last_pos = 0;
		litlen = (U32)(ip - anchor);

		/* check repCode */
		{
			U32 i, last_i = ZSTD_REP_CHECK + (ip == anchor);
			for (i = (ip == anchor); i < last_i; i++) {
				const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : rep[i];
				if ((repCur > 0) && (repCur < (S32)(ip - prefixStart)) &&
				    (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repCur, minMatch))) {
					mlen = (U32)ZSTD_count(ip + minMatch, ip + minMatch - repCur, iend) + minMatch;
					if (mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
						best_mlen = mlen;
						best_off = i;
						cur = 0;
						last_pos = 1;
						goto _storeSequence;
					}
					best_off = i - (ip == anchor);
					do {
						price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
						if (mlen > last_pos || price < opt[mlen].price)
							SET_PRICE(mlen, mlen, i, litlen, price); /* note : macro modifies last_pos */
						mlen--;
					} while (mlen >= minMatch);
				}
			}
		}

		match_num = ZSTD_BtGetAllMatches_selectMLS(ctx, ip, iend, maxSearches, mls, matches, minMatch);

		if (!last_pos && !match_num) {
			ip++;
			continue;
		}

		if (match_num && (matches[match_num - 1].len > sufficient_len || matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
			best_mlen = matches[match_num - 1].len;
			best_off = matches[match_num - 1].off;
			cur = 0;
			last_pos = 1;
			goto _storeSequence;
		}

		/* set prices using matches at position = 0 */
		best_mlen = (last_pos) ? last_pos : minMatch;
		for (u = 0; u < match_num; u++) {
			mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
			best_mlen = matches[u].len;
			while (mlen <= best_mlen) {
				price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
				if (mlen > last_pos || price < opt[mlen].price)
					SET_PRICE(mlen, mlen, matches[u].off, litlen, price); /* note : macro modifies last_pos */
				mlen++;
			}
		}

		if (last_pos < minMatch) {
			ip++;
			continue;
		}

		/* initialize opt[0] */
		{
			U32 i;
			for (i = 0; i < ZSTD_REP_NUM; i++)
				opt[0].rep[i] = rep[i];
		}
		opt[0].mlen = 1;
		opt[0].litlen = litlen;

		/* check further positions */
		for (cur = 1; cur <= last_pos; cur++) {
			inr = ip + cur;

			if (opt[cur - 1].mlen == 1) {
				litlen = opt[cur - 1].litlen + 1;
				if (cur > litlen) {
					price = opt[cur - litlen].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - litlen);
				} else
					price = ZSTD_getLiteralPrice(seqStorePtr, litlen, anchor);
			} else {
				litlen = 1;
				price = opt[cur - 1].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - 1);
			}

			if (cur > last_pos || price <= opt[cur].price)
				SET_PRICE(cur, 1, 0, litlen, price);

			if (cur == last_pos)
				break;

			if (inr > ilimit) /* last match must start at a minimum distance of 8 from oend */
				continue;

			mlen = opt[cur].mlen;
			if (opt[cur].off > ZSTD_REP_MOVE_OPT) {
				opt[cur].rep[2] = opt[cur - mlen].rep[1];
				opt[cur].rep[1] = opt[cur - mlen].rep[0];
				opt[cur].rep[0] = opt[cur].off - ZSTD_REP_MOVE_OPT;
			} else {
				opt[cur].rep[2] = (opt[cur].off > 1) ? opt[cur - mlen].rep[1] : opt[cur - mlen].rep[2];
				opt[cur].rep[1] = (opt[cur].off > 0) ? opt[cur - mlen].rep[0] : opt[cur - mlen].rep[1];
				opt[cur].rep[0] =
				    ((opt[cur].off == ZSTD_REP_MOVE_OPT) && (mlen != 1)) ? (opt[cur - mlen].rep[0] - 1) : (opt[cur - mlen].rep[opt[cur].off]);
			}

			best_mlen = minMatch;
			{
				U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
				for (i = (opt[cur].mlen != 1); i < last_i; i++) { /* check rep */
					const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (opt[cur].rep[0] - 1) : opt[cur].rep[i];
					if ((repCur > 0) && (repCur < (S32)(inr - prefixStart)) &&
					    (ZSTD_readMINMATCH(inr, minMatch) == ZSTD_readMINMATCH(inr - repCur, minMatch))) {
						mlen = (U32)ZSTD_count(inr + minMatch, inr + minMatch - repCur, iend) + minMatch;

						if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
							best_mlen = mlen;
							best_off = i;
							last_pos = cur + 1;
							goto _storeSequence;
						}

						best_off = i - (opt[cur].mlen != 1);
						if (mlen > best_mlen)
							best_mlen = mlen;

						do {
							if (opt[cur].mlen == 1) {
								litlen = opt[cur].litlen;
								if (cur > litlen) {
									price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr - litlen,
															best_off, mlen - MINMATCH, ultra);
								} else
									price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
							} else {
								litlen = 0;
								price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
							}

							if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
								SET_PRICE(cur + mlen, mlen, i, litlen, price);
							mlen--;
						} while (mlen >= minMatch);
					}
				}
			}

			match_num = ZSTD_BtGetAllMatches_selectMLS(ctx, inr, iend, maxSearches, mls, matches, best_mlen);

			if (match_num > 0 && (matches[match_num - 1].len > sufficient_len || cur + matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
				best_mlen = matches[match_num - 1].len;
				best_off = matches[match_num - 1].off;
				last_pos = cur + 1;
				goto _storeSequence;
			}

			/* set prices using matches at position = cur */
			for (u = 0; u < match_num; u++) {
				mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
				best_mlen = matches[u].len;

				while (mlen <= best_mlen) {
					if (opt[cur].mlen == 1) {
						litlen = opt[cur].litlen;
						if (cur > litlen)
							price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, ip + cur - litlen,
													matches[u].off - 1, mlen - MINMATCH, ultra);
						else
							price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
					} else {
						litlen = 0;
						price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, matches[u].off - 1, mlen - MINMATCH, ultra);
					}

					if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
						SET_PRICE(cur + mlen, mlen, matches[u].off, litlen, price);

					mlen++;
				}
			}
		}

		best_mlen = opt[last_pos].mlen;
		best_off = opt[last_pos].off;
		cur = last_pos - best_mlen;

	/* store sequence */
_storeSequence: /* cur, last_pos, best_mlen, best_off have to be set */
		opt[0].mlen = 1;

		while (1) {
			mlen = opt[cur].mlen;
			offset = opt[cur].off;
			opt[cur].mlen = best_mlen;
			opt[cur].off = best_off;
			best_mlen = mlen;
			best_off = offset;
			if (mlen > cur)
				break;
			cur -= mlen;
		}

		for (u = 0; u <= last_pos;) {
			u += opt[u].mlen;
		}

		for (cur = 0; cur < last_pos;) {
			mlen = opt[cur].mlen;
			if (mlen == 1) {
				ip++;
				cur++;
				continue;
			}
			offset = opt[cur].off;
			cur += mlen;
			litLength = (U32)(ip - anchor);

			if (offset > ZSTD_REP_MOVE_OPT) {
				rep[2] = rep[1];
				rep[1] = rep[0];
				rep[0] = offset - ZSTD_REP_MOVE_OPT;
				offset--;
			} else {
				if (offset != 0) {
					best_off = (offset == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : (rep[offset]);
					if (offset != 1)
						rep[2] = rep[1];
					rep[1] = rep[0];
					rep[0] = best_off;
				}
				if (litLength == 0)
					offset--;
			}

			ZSTD_updatePrice(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
			ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
			anchor = ip = ip + mlen;
		}
	} /* for (cur=0; cur < last_pos; ) */

	/* Save reps for next block */
	{
		int i;
		for (i = 0; i < ZSTD_REP_NUM; i++)
			ctx->repToConfirm[i] = rep[i];
	}

	/* Last Literals */
	{
		size_t const lastLLSize = iend - anchor;
		memcpy(seqStorePtr->lit, anchor, lastLLSize);
		seqStorePtr->lit += lastLLSize;
	}
}

FORCE_INLINE
void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const int ultra)
{
	seqStore_t *seqStorePtr = &(ctx->seqStore);
	const BYTE *const istart = (const BYTE *)src;
	const BYTE *ip = istart;
	const BYTE *anchor = istart;
	const BYTE *const iend = istart + srcSize;
	const BYTE *const ilimit = iend - 8;
	const BYTE *const base = ctx->base;
	const U32 lowestIndex = ctx->lowLimit;
	const U32 dictLimit = ctx->dictLimit;
	const BYTE *const prefixStart = base + dictLimit;
	const BYTE *const dictBase = ctx->dictBase;
	const BYTE *const dictEnd = dictBase + dictLimit;

	const U32 maxSearches = 1U << ctx->params.cParams.searchLog;
	const U32 sufficient_len = ctx->params.cParams.targetLength;
	const U32 mls = ctx->params.cParams.searchLength;
	const U32 minMatch = (ctx->params.cParams.searchLength == 3) ? 3 : 4;

	ZSTD_optimal_t *opt = seqStorePtr->priceTable;
	ZSTD_match_t *matches = seqStorePtr->matchTable;
	const BYTE *inr;

	/* init */
	U32 offset, rep[ZSTD_REP_NUM];
	{
		U32 i;
		for (i = 0; i < ZSTD_REP_NUM; i++)
			rep[i] = ctx->rep[i];
	}

	ctx->nextToUpdate3 = ctx->nextToUpdate;
	ZSTD_rescaleFreqs(seqStorePtr, (const BYTE *)src, srcSize);
	ip += (ip == prefixStart);

	/* Match Loop */
	while (ip < ilimit) {
		U32 cur, match_num, last_pos, litlen, price;
		U32 u, mlen, best_mlen, best_off, litLength;
		U32 curr = (U32)(ip - base);
		memset(opt, 0, sizeof(ZSTD_optimal_t));
		last_pos = 0;
		opt[0].litlen = (U32)(ip - anchor);

		/* check repCode */
		{
			U32 i, last_i = ZSTD_REP_CHECK + (ip == anchor);
			for (i = (ip == anchor); i < last_i; i++) {
				const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : rep[i];
				const U32 repIndex = (U32)(curr - repCur);
				const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
				const BYTE *const repMatch = repBase + repIndex;
				if ((repCur > 0 && repCur <= (S32)curr) &&
				    (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
				    && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch))) {
					/* repcode detected we should take it */
					const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
					mlen = (U32)ZSTD_count_2segments(ip + minMatch, repMatch + minMatch, iend, repEnd, prefixStart) + minMatch;

					if (mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
						best_mlen = mlen;
						best_off = i;
						cur = 0;
						last_pos = 1;
						goto _storeSequence;
					}

					best_off = i - (ip == anchor);
					litlen = opt[0].litlen;
					do {
						price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
						if (mlen > last_pos || price < opt[mlen].price)
							SET_PRICE(mlen, mlen, i, litlen, price); /* note : macro modifies last_pos */
						mlen--;
					} while (mlen >= minMatch);
				}
			}
		}

		match_num = ZSTD_BtGetAllMatches_selectMLS_extDict(ctx, ip, iend, maxSearches, mls, matches, minMatch); /* first search (depth 0) */

		if (!last_pos && !match_num) {
			ip++;
			continue;
		}

		{
			U32 i;
			for (i = 0; i < ZSTD_REP_NUM; i++)
				opt[0].rep[i] = rep[i];
		}
		opt[0].mlen = 1;

		if (match_num && (matches[match_num - 1].len > sufficient_len || matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
			best_mlen = matches[match_num - 1].len;
			best_off = matches[match_num - 1].off;
			cur = 0;
			last_pos = 1;
			goto _storeSequence;
		}

		best_mlen = (last_pos) ? last_pos : minMatch;

		/* set prices using matches at position = 0 */
		for (u = 0; u < match_num; u++) {
			mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
			best_mlen = matches[u].len;
			litlen = opt[0].litlen;
			while (mlen <= best_mlen) {
				price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
				if (mlen > last_pos || price < opt[mlen].price)
					SET_PRICE(mlen, mlen, matches[u].off, litlen, price);
				mlen++;
			}
		}

		if (last_pos < minMatch) {
			ip++;
			continue;
		}

		/* check further positions */
		for (cur = 1; cur <= last_pos; cur++) {
			inr = ip + cur;

			if (opt[cur - 1].mlen == 1) {
				litlen = opt[cur - 1].litlen + 1;
				if (cur > litlen) {
					price = opt[cur - litlen].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - litlen);
				} else
					price = ZSTD_getLiteralPrice(seqStorePtr, litlen, anchor);
			} else {
				litlen = 1;
				price = opt[cur - 1].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr - 1);
			}

			if (cur > last_pos || price <= opt[cur].price)
				SET_PRICE(cur, 1, 0, litlen, price);

			if (cur == last_pos)
				break;

			if (inr > ilimit) /* last match must start at a minimum distance of 8 from oend */
				continue;

			mlen = opt[cur].mlen;
			if (opt[cur].off > ZSTD_REP_MOVE_OPT) {
				opt[cur].rep[2] = opt[cur - mlen].rep[1];
				opt[cur].rep[1] = opt[cur - mlen].rep[0];
				opt[cur].rep[0] = opt[cur].off - ZSTD_REP_MOVE_OPT;
			} else {
				opt[cur].rep[2] = (opt[cur].off > 1) ? opt[cur - mlen].rep[1] : opt[cur - mlen].rep[2];
				opt[cur].rep[1] = (opt[cur].off > 0) ? opt[cur - mlen].rep[0] : opt[cur - mlen].rep[1];
				opt[cur].rep[0] =
				    ((opt[cur].off == ZSTD_REP_MOVE_OPT) && (mlen != 1)) ? (opt[cur - mlen].rep[0] - 1) : (opt[cur - mlen].rep[opt[cur].off]);
			}

			best_mlen = minMatch;
			{
				U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
				for (i = (mlen != 1); i < last_i; i++) {
					const S32 repCur = (i == ZSTD_REP_MOVE_OPT) ? (opt[cur].rep[0] - 1) : opt[cur].rep[i];
					const U32 repIndex = (U32)(curr + cur - repCur);
					const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
					const BYTE *const repMatch = repBase + repIndex;
					if ((repCur > 0 && repCur <= (S32)(curr + cur)) &&
					    (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
					    && (ZSTD_readMINMATCH(inr, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch))) {
						/* repcode detected */
						const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
						mlen = (U32)ZSTD_count_2segments(inr + minMatch, repMatch + minMatch, iend, repEnd, prefixStart) + minMatch;

						if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM) {
							best_mlen = mlen;
							best_off = i;
							last_pos = cur + 1;
							goto _storeSequence;
						}

						best_off = i - (opt[cur].mlen != 1);
						if (mlen > best_mlen)
							best_mlen = mlen;

						do {
							if (opt[cur].mlen == 1) {
								litlen = opt[cur].litlen;
								if (cur > litlen) {
									price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr - litlen,
															best_off, mlen - MINMATCH, ultra);
								} else
									price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
							} else {
								litlen = 0;
								price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
							}

							if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
								SET_PRICE(cur + mlen, mlen, i, litlen, price);
							mlen--;
						} while (mlen >= minMatch);
					}
				}
			}

			match_num = ZSTD_BtGetAllMatches_selectMLS_extDict(ctx, inr, iend, maxSearches, mls, matches, minMatch);

			if (match_num > 0 && (matches[match_num - 1].len > sufficient_len || cur + matches[match_num - 1].len >= ZSTD_OPT_NUM)) {
				best_mlen = matches[match_num - 1].len;
				best_off = matches[match_num - 1].off;
				last_pos = cur + 1;
				goto _storeSequence;
			}

			/* set prices using matches at position = cur */
			for (u = 0; u < match_num; u++) {
				mlen = (u > 0) ? matches[u - 1].len + 1 : best_mlen;
				best_mlen = matches[u].len;

				while (mlen <= best_mlen) {
					if (opt[cur].mlen == 1) {
						litlen = opt[cur].litlen;
						if (cur > litlen)
							price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, ip + cur - litlen,
													matches[u].off - 1, mlen - MINMATCH, ultra);
						else
							price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[u].off - 1, mlen - MINMATCH, ultra);
					} else {
						litlen = 0;
						price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, matches[u].off - 1, mlen - MINMATCH, ultra);
					}

					if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
						SET_PRICE(cur + mlen, mlen, matches[u].off, litlen, price);

					mlen++;
				}
			}
		} /* for (cur = 1; cur <= last_pos; cur++) */

		best_mlen = opt[last_pos].mlen;
		best_off = opt[last_pos].off;
		cur = last_pos - best_mlen;

	/* store sequence */
_storeSequence: /* cur, last_pos, best_mlen, best_off have to be set */
		opt[0].mlen = 1;

		while (1) {
			mlen = opt[cur].mlen;
			offset = opt[cur].off;
			opt[cur].mlen = best_mlen;
			opt[cur].off = best_off;
			best_mlen = mlen;
			best_off = offset;
			if (mlen > cur)
				break;
			cur -= mlen;
		}

		for (u = 0; u <= last_pos;) {
			u += opt[u].mlen;
		}

		for (cur = 0; cur < last_pos;) {
			mlen = opt[cur].mlen;
			if (mlen == 1) {
				ip++;
				cur++;
				continue;
			}
			offset = opt[cur].off;
			cur += mlen;
			litLength = (U32)(ip - anchor);

			if (offset > ZSTD_REP_MOVE_OPT) {
				rep[2] = rep[1];
				rep[1] = rep[0];
				rep[0] = offset - ZSTD_REP_MOVE_OPT;
				offset--;
			} else {
				if (offset != 0) {
					best_off = (offset == ZSTD_REP_MOVE_OPT) ? (rep[0] - 1) : (rep[offset]);
					if (offset != 1)
						rep[2] = rep[1];
					rep[1] = rep[0];
					rep[0] = best_off;
				}

				if (litLength == 0)
					offset--;
			}

			ZSTD_updatePrice(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
			ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen - MINMATCH);
			anchor = ip = ip + mlen;
		}
	} /* for (cur=0; cur < last_pos; ) */

	/* Save reps for next block */
	{
		int i;
		for (i = 0; i < ZSTD_REP_NUM; i++)
			ctx->repToConfirm[i] = rep[i];
	}

	/* Last Literals */
	{
		size_t lastLLSize = iend - anchor;
		memcpy(seqStorePtr->lit, anchor, lastLLSize);
		seqStorePtr->lit += lastLLSize;
	}
}

#endif /* ZSTD_OPT_H_91842398743 */