xref: /OK3568_Linux_fs/kernel/lib/zstd/compress.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)

/**
 * Copyright (c) 2016-present, 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").
 */

/*-*************************************
*  Dependencies
***************************************/
#include "fse.h"
#include "huf.h"
#include "mem.h"
#include "zstd_internal.h" /* includes zstd.h */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h> /* memset */

/*-*************************************
*  Constants
***************************************/
static const U32 g_searchStrength = 8; /* control skip over incompressible data */
#define HASH_READ_SIZE 8
typedef enum { ZSTDcs_created = 0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;

/*-*************************************
*  Helper functions
***************************************/
size_t ZSTD_compressBound(size_t srcSize) { return FSE_compressBound(srcSize) + 12; }

/*-*************************************
*  Sequence storage
***************************************/
static void ZSTD_resetSeqStore(seqStore_t *ssPtr)
{
	ssPtr->lit = ssPtr->litStart;
	ssPtr->sequences = ssPtr->sequencesStart;
	ssPtr->longLengthID = 0;
}

/*-*************************************
*  Context memory management
***************************************/
struct ZSTD_CCtx_s {
	const BYTE *nextSrc;  /* next block here to continue on curr prefix */
	const BYTE *base;     /* All regular indexes relative to this position */
	const BYTE *dictBase; /* extDict indexes relative to this position */
	U32 dictLimit;	/* below that point, need extDict */
	U32 lowLimit;	 /* below that point, no more data */
	U32 nextToUpdate;     /* index from which to continue dictionary update */
	U32 nextToUpdate3;    /* index from which to continue dictionary update */
	U32 hashLog3;	 /* dispatch table : larger == faster, more memory */
	U32 loadedDictEnd;    /* index of end of dictionary */
	U32 forceWindow;      /* force back-references to respect limit of 1<<wLog, even for dictionary */
	U32 forceRawDict;     /* Force loading dictionary in "content-only" mode (no header analysis) */
	ZSTD_compressionStage_e stage;
	U32 rep[ZSTD_REP_NUM];
	U32 repToConfirm[ZSTD_REP_NUM];
	U32 dictID;
	ZSTD_parameters params;
	void *workSpace;
	size_t workSpaceSize;
	size_t blockSize;
	U64 frameContentSize;
	struct xxh64_state xxhState;
	ZSTD_customMem customMem;

	seqStore_t seqStore; /* sequences storage ptrs */
	U32 *hashTable;
	U32 *hashTable3;
	U32 *chainTable;
	HUF_CElt *hufTable;
	U32 flagStaticTables;
	HUF_repeat flagStaticHufTable;
	FSE_CTable offcodeCTable[FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)];
	FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)];
	FSE_CTable litlengthCTable[FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)];
	unsigned tmpCounters[HUF_COMPRESS_WORKSPACE_SIZE_U32];
};

size_t ZSTD_CCtxWorkspaceBound(ZSTD_compressionParameters cParams)
{
	size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, (size_t)1 << cParams.windowLog);
	U32 const divider = (cParams.searchLength == 3) ? 3 : 4;
	size_t const maxNbSeq = blockSize / divider;
	size_t const tokenSpace = blockSize + 11 * maxNbSeq;
	size_t const chainSize = (cParams.strategy == ZSTD_fast) ? 0 : (1 << cParams.chainLog);
	size_t const hSize = ((size_t)1) << cParams.hashLog;
	U32 const hashLog3 = (cParams.searchLength > 3) ? 0 : MIN(ZSTD_HASHLOG3_MAX, cParams.windowLog);
	size_t const h3Size = ((size_t)1) << hashLog3;
	size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
	size_t const optSpace =
	    ((MaxML + 1) + (MaxLL + 1) + (MaxOff + 1) + (1 << Litbits)) * sizeof(U32) + (ZSTD_OPT_NUM + 1) * (sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t));
	size_t const workspaceSize = tableSpace + (256 * sizeof(U32)) /* huffTable */ + tokenSpace +
				     (((cParams.strategy == ZSTD_btopt) || (cParams.strategy == ZSTD_btopt2)) ? optSpace : 0);

	return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_CCtx)) + ZSTD_ALIGN(workspaceSize);
}

static ZSTD_CCtx *ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
{
	ZSTD_CCtx *cctx;
	if (!customMem.customAlloc || !customMem.customFree)
		return NULL;
	cctx = (ZSTD_CCtx *)ZSTD_malloc(sizeof(ZSTD_CCtx), customMem);
	if (!cctx)
		return NULL;
	memset(cctx, 0, sizeof(ZSTD_CCtx));
	cctx->customMem = customMem;
	return cctx;
}

ZSTD_CCtx *ZSTD_initCCtx(void *workspace, size_t workspaceSize)
{
	ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
	ZSTD_CCtx *cctx = ZSTD_createCCtx_advanced(stackMem);
	if (cctx) {
		cctx->workSpace = ZSTD_stackAllocAll(cctx->customMem.opaque, &cctx->workSpaceSize);
	}
	return cctx;
}

size_t ZSTD_freeCCtx(ZSTD_CCtx *cctx)
{
	if (cctx == NULL)
		return 0; /* support free on NULL */
	ZSTD_free(cctx->workSpace, cctx->customMem);
	ZSTD_free(cctx, cctx->customMem);
	return 0; /* reserved as a potential error code in the future */
}

const seqStore_t *ZSTD_getSeqStore(const ZSTD_CCtx *ctx) /* hidden interface */ { return &(ctx->seqStore); }

static ZSTD_parameters ZSTD_getParamsFromCCtx(const ZSTD_CCtx *cctx) { return cctx->params; }

/** ZSTD_checkParams() :
	ensure param values remain within authorized range.
	@return : 0, or an error code if one value is beyond authorized range */
size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams)
{
#define CLAMPCHECK(val, min, max)                                       \
	{                                                               \
		if ((val < min) | (val > max))                          \
			return ERROR(compressionParameter_unsupported); \
	}
	CLAMPCHECK(cParams.windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
	CLAMPCHECK(cParams.chainLog, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
	CLAMPCHECK(cParams.hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
	CLAMPCHECK(cParams.searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
	CLAMPCHECK(cParams.searchLength, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
	CLAMPCHECK(cParams.targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
	if ((U32)(cParams.strategy) > (U32)ZSTD_btopt2)
		return ERROR(compressionParameter_unsupported);
	return 0;
}

/** ZSTD_cycleLog() :
 *  condition for correct operation : hashLog > 1 */
static U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat)
{
	U32 const btScale = ((U32)strat >= (U32)ZSTD_btlazy2);
	return hashLog - btScale;
}

/** ZSTD_adjustCParams() :
	optimize `cPar` for a given input (`srcSize` and `dictSize`).
	mostly downsizing to reduce memory consumption and initialization.
	Both `srcSize` and `dictSize` are optional (use 0 if unknown),
	but if both are 0, no optimization can be done.
	Note : cPar is considered validated at this stage. Use ZSTD_checkParams() to ensure that. */
ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
{
	if (srcSize + dictSize == 0)
		return cPar; /* no size information available : no adjustment */

	/* resize params, to use less memory when necessary */
	{
		U32 const minSrcSize = (srcSize == 0) ? 500 : 0;
		U64 const rSize = srcSize + dictSize + minSrcSize;
		if (rSize < ((U64)1 << ZSTD_WINDOWLOG_MAX)) {
			U32 const srcLog = MAX(ZSTD_HASHLOG_MIN, ZSTD_highbit32((U32)(rSize)-1) + 1);
			if (cPar.windowLog > srcLog)
				cPar.windowLog = srcLog;
		}
	}
	if (cPar.hashLog > cPar.windowLog)
		cPar.hashLog = cPar.windowLog;
	{
		U32 const cycleLog = ZSTD_cycleLog(cPar.chainLog, cPar.strategy);
		if (cycleLog > cPar.windowLog)
			cPar.chainLog -= (cycleLog - cPar.windowLog);
	}

	if (cPar.windowLog < ZSTD_WINDOWLOG_ABSOLUTEMIN)
		cPar.windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN; /* required for frame header */

	return cPar;
}

static U32 ZSTD_equivalentParams(ZSTD_parameters param1, ZSTD_parameters param2)
{
	return (param1.cParams.hashLog == param2.cParams.hashLog) & (param1.cParams.chainLog == param2.cParams.chainLog) &
	       (param1.cParams.strategy == param2.cParams.strategy) & ((param1.cParams.searchLength == 3) == (param2.cParams.searchLength == 3));
}

/*! ZSTD_continueCCtx() :
	reuse CCtx without reset (note : requires no dictionary) */
static size_t ZSTD_continueCCtx(ZSTD_CCtx *cctx, ZSTD_parameters params, U64 frameContentSize)
{
	U32 const end = (U32)(cctx->nextSrc - cctx->base);
	cctx->params = params;
	cctx->frameContentSize = frameContentSize;
	cctx->lowLimit = end;
	cctx->dictLimit = end;
	cctx->nextToUpdate = end + 1;
	cctx->stage = ZSTDcs_init;
	cctx->dictID = 0;
	cctx->loadedDictEnd = 0;
	{
		int i;
		for (i = 0; i < ZSTD_REP_NUM; i++)
			cctx->rep[i] = repStartValue[i];
	}
	cctx->seqStore.litLengthSum = 0; /* force reset of btopt stats */
	xxh64_reset(&cctx->xxhState, 0);
	return 0;
}

typedef enum { ZSTDcrp_continue, ZSTDcrp_noMemset, ZSTDcrp_fullReset } ZSTD_compResetPolicy_e;

/*! ZSTD_resetCCtx_advanced() :
	note : `params` must be validated */
static size_t ZSTD_resetCCtx_advanced(ZSTD_CCtx *zc, ZSTD_parameters params, U64 frameContentSize, ZSTD_compResetPolicy_e const crp)
{
	if (crp == ZSTDcrp_continue)
		if (ZSTD_equivalentParams(params, zc->params)) {
			zc->flagStaticTables = 0;
			zc->flagStaticHufTable = HUF_repeat_none;
			return ZSTD_continueCCtx(zc, params, frameContentSize);
		}

	{
		size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, (size_t)1 << params.cParams.windowLog);
		U32 const divider = (params.cParams.searchLength == 3) ? 3 : 4;
		size_t const maxNbSeq = blockSize / divider;
		size_t const tokenSpace = blockSize + 11 * maxNbSeq;
		size_t const chainSize = (params.cParams.strategy == ZSTD_fast) ? 0 : (1 << params.cParams.chainLog);
		size_t const hSize = ((size_t)1) << params.cParams.hashLog;
		U32 const hashLog3 = (params.cParams.searchLength > 3) ? 0 : MIN(ZSTD_HASHLOG3_MAX, params.cParams.windowLog);
		size_t const h3Size = ((size_t)1) << hashLog3;
		size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
		void *ptr;

		/* Check if workSpace is large enough, alloc a new one if needed */
		{
			size_t const optSpace = ((MaxML + 1) + (MaxLL + 1) + (MaxOff + 1) + (1 << Litbits)) * sizeof(U32) +
						(ZSTD_OPT_NUM + 1) * (sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t));
			size_t const neededSpace = tableSpace + (256 * sizeof(U32)) /* huffTable */ + tokenSpace +
						   (((params.cParams.strategy == ZSTD_btopt) || (params.cParams.strategy == ZSTD_btopt2)) ? optSpace : 0);
			if (zc->workSpaceSize < neededSpace) {
				ZSTD_free(zc->workSpace, zc->customMem);
				zc->workSpace = ZSTD_malloc(neededSpace, zc->customMem);
				if (zc->workSpace == NULL)
					return ERROR(memory_allocation);
				zc->workSpaceSize = neededSpace;
			}
		}

		if (crp != ZSTDcrp_noMemset)
			memset(zc->workSpace, 0, tableSpace); /* reset tables only */
		xxh64_reset(&zc->xxhState, 0);
		zc->hashLog3 = hashLog3;
		zc->hashTable = (U32 *)(zc->workSpace);
		zc->chainTable = zc->hashTable + hSize;
		zc->hashTable3 = zc->chainTable + chainSize;
		ptr = zc->hashTable3 + h3Size;
		zc->hufTable = (HUF_CElt *)ptr;
		zc->flagStaticTables = 0;
		zc->flagStaticHufTable = HUF_repeat_none;
		ptr = ((U32 *)ptr) + 256; /* note : HUF_CElt* is incomplete type, size is simulated using U32 */

		zc->nextToUpdate = 1;
		zc->nextSrc = NULL;
		zc->base = NULL;
		zc->dictBase = NULL;
		zc->dictLimit = 0;
		zc->lowLimit = 0;
		zc->params = params;
		zc->blockSize = blockSize;
		zc->frameContentSize = frameContentSize;
		{
			int i;
			for (i = 0; i < ZSTD_REP_NUM; i++)
				zc->rep[i] = repStartValue[i];
		}

		if ((params.cParams.strategy == ZSTD_btopt) || (params.cParams.strategy == ZSTD_btopt2)) {
			zc->seqStore.litFreq = (U32 *)ptr;
			zc->seqStore.litLengthFreq = zc->seqStore.litFreq + (1 << Litbits);
			zc->seqStore.matchLengthFreq = zc->seqStore.litLengthFreq + (MaxLL + 1);
			zc->seqStore.offCodeFreq = zc->seqStore.matchLengthFreq + (MaxML + 1);
			ptr = zc->seqStore.offCodeFreq + (MaxOff + 1);
			zc->seqStore.matchTable = (ZSTD_match_t *)ptr;
			ptr = zc->seqStore.matchTable + ZSTD_OPT_NUM + 1;
			zc->seqStore.priceTable = (ZSTD_optimal_t *)ptr;
			ptr = zc->seqStore.priceTable + ZSTD_OPT_NUM + 1;
			zc->seqStore.litLengthSum = 0;
		}
		zc->seqStore.sequencesStart = (seqDef *)ptr;
		ptr = zc->seqStore.sequencesStart + maxNbSeq;
		zc->seqStore.llCode = (BYTE *)ptr;
		zc->seqStore.mlCode = zc->seqStore.llCode + maxNbSeq;
		zc->seqStore.ofCode = zc->seqStore.mlCode + maxNbSeq;
		zc->seqStore.litStart = zc->seqStore.ofCode + maxNbSeq;

		zc->stage = ZSTDcs_init;
		zc->dictID = 0;
		zc->loadedDictEnd = 0;

		return 0;
	}
}

/* ZSTD_invalidateRepCodes() :
 * ensures next compression will not use repcodes from previous block.
 * Note : only works with regular variant;
 *        do not use with extDict variant ! */
void ZSTD_invalidateRepCodes(ZSTD_CCtx *cctx)
{
	int i;
	for (i = 0; i < ZSTD_REP_NUM; i++)
		cctx->rep[i] = 0;
}

/*! ZSTD_copyCCtx() :
*   Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
*   Only works during stage ZSTDcs_init (i.e. after creation, but before first call to ZSTD_compressContinue()).
*   @return : 0, or an error code */
size_t ZSTD_copyCCtx(ZSTD_CCtx *dstCCtx, const ZSTD_CCtx *srcCCtx, unsigned long long pledgedSrcSize)
{
	if (srcCCtx->stage != ZSTDcs_init)
		return ERROR(stage_wrong);

	memcpy(&dstCCtx->customMem, &srcCCtx->customMem, sizeof(ZSTD_customMem));
	{
		ZSTD_parameters params = srcCCtx->params;
		params.fParams.contentSizeFlag = (pledgedSrcSize > 0);
		ZSTD_resetCCtx_advanced(dstCCtx, params, pledgedSrcSize, ZSTDcrp_noMemset);
	}

	/* copy tables */
	{
		size_t const chainSize = (srcCCtx->params.cParams.strategy == ZSTD_fast) ? 0 : (1 << srcCCtx->params.cParams.chainLog);
		size_t const hSize = ((size_t)1) << srcCCtx->params.cParams.hashLog;
		size_t const h3Size = (size_t)1 << srcCCtx->hashLog3;
		size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
		memcpy(dstCCtx->workSpace, srcCCtx->workSpace, tableSpace);
	}

	/* copy dictionary offsets */
	dstCCtx->nextToUpdate = srcCCtx->nextToUpdate;
	dstCCtx->nextToUpdate3 = srcCCtx->nextToUpdate3;
	dstCCtx->nextSrc = srcCCtx->nextSrc;
	dstCCtx->base = srcCCtx->base;
	dstCCtx->dictBase = srcCCtx->dictBase;
	dstCCtx->dictLimit = srcCCtx->dictLimit;
	dstCCtx->lowLimit = srcCCtx->lowLimit;
	dstCCtx->loadedDictEnd = srcCCtx->loadedDictEnd;
	dstCCtx->dictID = srcCCtx->dictID;

	/* copy entropy tables */
	dstCCtx->flagStaticTables = srcCCtx->flagStaticTables;
	dstCCtx->flagStaticHufTable = srcCCtx->flagStaticHufTable;
	if (srcCCtx->flagStaticTables) {
		memcpy(dstCCtx->litlengthCTable, srcCCtx->litlengthCTable, sizeof(dstCCtx->litlengthCTable));
		memcpy(dstCCtx->matchlengthCTable, srcCCtx->matchlengthCTable, sizeof(dstCCtx->matchlengthCTable));
		memcpy(dstCCtx->offcodeCTable, srcCCtx->offcodeCTable, sizeof(dstCCtx->offcodeCTable));
	}
	if (srcCCtx->flagStaticHufTable) {
		memcpy(dstCCtx->hufTable, srcCCtx->hufTable, 256 * 4);
	}

	return 0;
}

/*! ZSTD_reduceTable() :
*   reduce table indexes by `reducerValue` */
static void ZSTD_reduceTable(U32 *const table, U32 const size, U32 const reducerValue)
{
	U32 u;
	for (u = 0; u < size; u++) {
		if (table[u] < reducerValue)
			table[u] = 0;
		else
			table[u] -= reducerValue;
	}
}

/*! ZSTD_reduceIndex() :
*   rescale all indexes to avoid future overflow (indexes are U32) */
static void ZSTD_reduceIndex(ZSTD_CCtx *zc, const U32 reducerValue)
{
	{
		U32 const hSize = 1 << zc->params.cParams.hashLog;
		ZSTD_reduceTable(zc->hashTable, hSize, reducerValue);
	}

	{
		U32 const chainSize = (zc->params.cParams.strategy == ZSTD_fast) ? 0 : (1 << zc->params.cParams.chainLog);
		ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue);
	}

	{
		U32 const h3Size = (zc->hashLog3) ? 1 << zc->hashLog3 : 0;
		ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue);
	}
}

/*-*******************************************************
*  Block entropic compression
*********************************************************/

/* See doc/zstd_compression_format.md for detailed format description */

size_t ZSTD_noCompressBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	if (srcSize + ZSTD_blockHeaderSize > dstCapacity)
		return ERROR(dstSize_tooSmall);
	memcpy((BYTE *)dst + ZSTD_blockHeaderSize, src, srcSize);
	ZSTD_writeLE24(dst, (U32)(srcSize << 2) + (U32)bt_raw);
	return ZSTD_blockHeaderSize + srcSize;
}

static size_t ZSTD_noCompressLiterals(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	BYTE *const ostart = (BYTE * const)dst;
	U32 const flSize = 1 + (srcSize > 31) + (srcSize > 4095);

	if (srcSize + flSize > dstCapacity)
		return ERROR(dstSize_tooSmall);

	switch (flSize) {
	case 1: /* 2 - 1 - 5 */ ostart[0] = (BYTE)((U32)set_basic + (srcSize << 3)); break;
	case 2: /* 2 - 2 - 12 */ ZSTD_writeLE16(ostart, (U16)((U32)set_basic + (1 << 2) + (srcSize << 4))); break;
	default: /*note : should not be necessary : flSize is within {1,2,3} */
	case 3: /* 2 - 2 - 20 */ ZSTD_writeLE32(ostart, (U32)((U32)set_basic + (3 << 2) + (srcSize << 4))); break;
	}

	memcpy(ostart + flSize, src, srcSize);
	return srcSize + flSize;
}

static size_t ZSTD_compressRleLiteralsBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	BYTE *const ostart = (BYTE * const)dst;
	U32 const flSize = 1 + (srcSize > 31) + (srcSize > 4095);

	(void)dstCapacity; /* dstCapacity already guaranteed to be >=4, hence large enough */

	switch (flSize) {
	case 1: /* 2 - 1 - 5 */ ostart[0] = (BYTE)((U32)set_rle + (srcSize << 3)); break;
	case 2: /* 2 - 2 - 12 */ ZSTD_writeLE16(ostart, (U16)((U32)set_rle + (1 << 2) + (srcSize << 4))); break;
	default: /*note : should not be necessary : flSize is necessarily within {1,2,3} */
	case 3: /* 2 - 2 - 20 */ ZSTD_writeLE32(ostart, (U32)((U32)set_rle + (3 << 2) + (srcSize << 4))); break;
	}

	ostart[flSize] = *(const BYTE *)src;
	return flSize + 1;
}

static size_t ZSTD_minGain(size_t srcSize) { return (srcSize >> 6) + 2; }

static size_t ZSTD_compressLiterals(ZSTD_CCtx *zc, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	size_t const minGain = ZSTD_minGain(srcSize);
	size_t const lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
	BYTE *const ostart = (BYTE *)dst;
	U32 singleStream = srcSize < 256;
	symbolEncodingType_e hType = set_compressed;
	size_t cLitSize;

/* small ? don't even attempt compression (speed opt) */
#define LITERAL_NOENTROPY 63
	{
		size_t const minLitSize = zc->flagStaticHufTable == HUF_repeat_valid ? 6 : LITERAL_NOENTROPY;
		if (srcSize <= minLitSize)
			return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
	}

	if (dstCapacity < lhSize + 1)
		return ERROR(dstSize_tooSmall); /* not enough space for compression */
	{
		HUF_repeat repeat = zc->flagStaticHufTable;
		int const preferRepeat = zc->params.cParams.strategy < ZSTD_lazy ? srcSize <= 1024 : 0;
		if (repeat == HUF_repeat_valid && lhSize == 3)
			singleStream = 1;
		cLitSize = singleStream ? HUF_compress1X_repeat(ostart + lhSize, dstCapacity - lhSize, src, srcSize, 255, 11, zc->tmpCounters,
								sizeof(zc->tmpCounters), zc->hufTable, &repeat, preferRepeat)
					: HUF_compress4X_repeat(ostart + lhSize, dstCapacity - lhSize, src, srcSize, 255, 11, zc->tmpCounters,
								sizeof(zc->tmpCounters), zc->hufTable, &repeat, preferRepeat);
		if (repeat != HUF_repeat_none) {
			hType = set_repeat;
		} /* reused the existing table */
		else {
			zc->flagStaticHufTable = HUF_repeat_check;
		} /* now have a table to reuse */
	}

	if ((cLitSize == 0) | (cLitSize >= srcSize - minGain)) {
		zc->flagStaticHufTable = HUF_repeat_none;
		return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
	}
	if (cLitSize == 1) {
		zc->flagStaticHufTable = HUF_repeat_none;
		return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
	}

	/* Build header */
	switch (lhSize) {
	case 3: /* 2 - 2 - 10 - 10 */
	{
		U32 const lhc = hType + ((!singleStream) << 2) + ((U32)srcSize << 4) + ((U32)cLitSize << 14);
		ZSTD_writeLE24(ostart, lhc);
		break;
	}
	case 4: /* 2 - 2 - 14 - 14 */
	{
		U32 const lhc = hType + (2 << 2) + ((U32)srcSize << 4) + ((U32)cLitSize << 18);
		ZSTD_writeLE32(ostart, lhc);
		break;
	}
	default: /* should not be necessary, lhSize is only {3,4,5} */
	case 5:  /* 2 - 2 - 18 - 18 */
	{
		U32 const lhc = hType + (3 << 2) + ((U32)srcSize << 4) + ((U32)cLitSize << 22);
		ZSTD_writeLE32(ostart, lhc);
		ostart[4] = (BYTE)(cLitSize >> 10);
		break;
	}
	}
	return lhSize + cLitSize;
}

static const BYTE LL_Code[64] = {0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15, 16, 16, 17, 17, 18, 18,
				 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23,
				 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24};

static const BYTE ML_Code[128] = {0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
				  26, 27, 28, 29, 30, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37, 38, 38, 38, 38,
				  38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,
				  40, 40, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 42, 42, 42, 42, 42, 42, 42, 42,
				  42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42};

void ZSTD_seqToCodes(const seqStore_t *seqStorePtr)
{
	BYTE const LL_deltaCode = 19;
	BYTE const ML_deltaCode = 36;
	const seqDef *const sequences = seqStorePtr->sequencesStart;
	BYTE *const llCodeTable = seqStorePtr->llCode;
	BYTE *const ofCodeTable = seqStorePtr->ofCode;
	BYTE *const mlCodeTable = seqStorePtr->mlCode;
	U32 const nbSeq = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
	U32 u;
	for (u = 0; u < nbSeq; u++) {
		U32 const llv = sequences[u].litLength;
		U32 const mlv = sequences[u].matchLength;
		llCodeTable[u] = (llv > 63) ? (BYTE)ZSTD_highbit32(llv) + LL_deltaCode : LL_Code[llv];
		ofCodeTable[u] = (BYTE)ZSTD_highbit32(sequences[u].offset);
		mlCodeTable[u] = (mlv > 127) ? (BYTE)ZSTD_highbit32(mlv) + ML_deltaCode : ML_Code[mlv];
	}
	if (seqStorePtr->longLengthID == 1)
		llCodeTable[seqStorePtr->longLengthPos] = MaxLL;
	if (seqStorePtr->longLengthID == 2)
		mlCodeTable[seqStorePtr->longLengthPos] = MaxML;
}

ZSTD_STATIC size_t ZSTD_compressSequences_internal(ZSTD_CCtx *zc, void *dst, size_t dstCapacity)
{
	const int longOffsets = zc->params.cParams.windowLog > STREAM_ACCUMULATOR_MIN;
	const seqStore_t *seqStorePtr = &(zc->seqStore);
	FSE_CTable *CTable_LitLength = zc->litlengthCTable;
	FSE_CTable *CTable_OffsetBits = zc->offcodeCTable;
	FSE_CTable *CTable_MatchLength = zc->matchlengthCTable;
	U32 LLtype, Offtype, MLtype; /* compressed, raw or rle */
	const seqDef *const sequences = seqStorePtr->sequencesStart;
	const BYTE *const ofCodeTable = seqStorePtr->ofCode;
	const BYTE *const llCodeTable = seqStorePtr->llCode;
	const BYTE *const mlCodeTable = seqStorePtr->mlCode;
	BYTE *const ostart = (BYTE *)dst;
	BYTE *const oend = ostart + dstCapacity;
	BYTE *op = ostart;
	size_t const nbSeq = seqStorePtr->sequences - seqStorePtr->sequencesStart;
	BYTE *seqHead;

	U32 *count;
	S16 *norm;
	U32 *workspace;
	size_t workspaceSize = sizeof(zc->tmpCounters);
	{
		size_t spaceUsed32 = 0;
		count = (U32 *)zc->tmpCounters + spaceUsed32;
		spaceUsed32 += MaxSeq + 1;
		norm = (S16 *)((U32 *)zc->tmpCounters + spaceUsed32);
		spaceUsed32 += ALIGN(sizeof(S16) * (MaxSeq + 1), sizeof(U32)) >> 2;

		workspace = (U32 *)zc->tmpCounters + spaceUsed32;
		workspaceSize -= (spaceUsed32 << 2);
	}

	/* Compress literals */
	{
		const BYTE *const literals = seqStorePtr->litStart;
		size_t const litSize = seqStorePtr->lit - literals;
		size_t const cSize = ZSTD_compressLiterals(zc, op, dstCapacity, literals, litSize);
		if (ZSTD_isError(cSize))
			return cSize;
		op += cSize;
	}

	/* Sequences Header */
	if ((oend - op) < 3 /*max nbSeq Size*/ + 1 /*seqHead */)
		return ERROR(dstSize_tooSmall);
	if (nbSeq < 0x7F)
		*op++ = (BYTE)nbSeq;
	else if (nbSeq < LONGNBSEQ)
		op[0] = (BYTE)((nbSeq >> 8) + 0x80), op[1] = (BYTE)nbSeq, op += 2;
	else
		op[0] = 0xFF, ZSTD_writeLE16(op + 1, (U16)(nbSeq - LONGNBSEQ)), op += 3;
	if (nbSeq == 0)
		return op - ostart;

	/* seqHead : flags for FSE encoding type */
	seqHead = op++;

#define MIN_SEQ_FOR_DYNAMIC_FSE 64
#define MAX_SEQ_FOR_STATIC_FSE 1000

	/* convert length/distances into codes */
	ZSTD_seqToCodes(seqStorePtr);

	/* CTable for Literal Lengths */
	{
		U32 max = MaxLL;
		size_t const mostFrequent = FSE_countFast_wksp(count, &max, llCodeTable, nbSeq, workspace);
		if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
			*op++ = llCodeTable[0];
			FSE_buildCTable_rle(CTable_LitLength, (BYTE)max);
			LLtype = set_rle;
		} else if ((zc->flagStaticTables) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
			LLtype = set_repeat;
		} else if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (LL_defaultNormLog - 1)))) {
			FSE_buildCTable_wksp(CTable_LitLength, LL_defaultNorm, MaxLL, LL_defaultNormLog, workspace, workspaceSize);
			LLtype = set_basic;
		} else {
			size_t nbSeq_1 = nbSeq;
			const U32 tableLog = FSE_optimalTableLog(LLFSELog, nbSeq, max);
			if (count[llCodeTable[nbSeq - 1]] > 1) {
				count[llCodeTable[nbSeq - 1]]--;
				nbSeq_1--;
			}
			FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
			{
				size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
				if (FSE_isError(NCountSize))
					return NCountSize;
				op += NCountSize;
			}
			FSE_buildCTable_wksp(CTable_LitLength, norm, max, tableLog, workspace, workspaceSize);
			LLtype = set_compressed;
		}
	}

	/* CTable for Offsets */
	{
		U32 max = MaxOff;
		size_t const mostFrequent = FSE_countFast_wksp(count, &max, ofCodeTable, nbSeq, workspace);
		if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
			*op++ = ofCodeTable[0];
			FSE_buildCTable_rle(CTable_OffsetBits, (BYTE)max);
			Offtype = set_rle;
		} else if ((zc->flagStaticTables) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
			Offtype = set_repeat;
		} else if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (OF_defaultNormLog - 1)))) {
			FSE_buildCTable_wksp(CTable_OffsetBits, OF_defaultNorm, MaxOff, OF_defaultNormLog, workspace, workspaceSize);
			Offtype = set_basic;
		} else {
			size_t nbSeq_1 = nbSeq;
			const U32 tableLog = FSE_optimalTableLog(OffFSELog, nbSeq, max);
			if (count[ofCodeTable[nbSeq - 1]] > 1) {
				count[ofCodeTable[nbSeq - 1]]--;
				nbSeq_1--;
			}
			FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
			{
				size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
				if (FSE_isError(NCountSize))
					return NCountSize;
				op += NCountSize;
			}
			FSE_buildCTable_wksp(CTable_OffsetBits, norm, max, tableLog, workspace, workspaceSize);
			Offtype = set_compressed;
		}
	}

	/* CTable for MatchLengths */
	{
		U32 max = MaxML;
		size_t const mostFrequent = FSE_countFast_wksp(count, &max, mlCodeTable, nbSeq, workspace);
		if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
			*op++ = *mlCodeTable;
			FSE_buildCTable_rle(CTable_MatchLength, (BYTE)max);
			MLtype = set_rle;
		} else if ((zc->flagStaticTables) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
			MLtype = set_repeat;
		} else if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (ML_defaultNormLog - 1)))) {
			FSE_buildCTable_wksp(CTable_MatchLength, ML_defaultNorm, MaxML, ML_defaultNormLog, workspace, workspaceSize);
			MLtype = set_basic;
		} else {
			size_t nbSeq_1 = nbSeq;
			const U32 tableLog = FSE_optimalTableLog(MLFSELog, nbSeq, max);
			if (count[mlCodeTable[nbSeq - 1]] > 1) {
				count[mlCodeTable[nbSeq - 1]]--;
				nbSeq_1--;
			}
			FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
			{
				size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
				if (FSE_isError(NCountSize))
					return NCountSize;
				op += NCountSize;
			}
			FSE_buildCTable_wksp(CTable_MatchLength, norm, max, tableLog, workspace, workspaceSize);
			MLtype = set_compressed;
		}
	}

	*seqHead = (BYTE)((LLtype << 6) + (Offtype << 4) + (MLtype << 2));
	zc->flagStaticTables = 0;

	/* Encoding Sequences */
	{
		BIT_CStream_t blockStream;
		FSE_CState_t stateMatchLength;
		FSE_CState_t stateOffsetBits;
		FSE_CState_t stateLitLength;

		CHECK_E(BIT_initCStream(&blockStream, op, oend - op), dstSize_tooSmall); /* not enough space remaining */

		/* first symbols */
		FSE_initCState2(&stateMatchLength, CTable_MatchLength, mlCodeTable[nbSeq - 1]);
		FSE_initCState2(&stateOffsetBits, CTable_OffsetBits, ofCodeTable[nbSeq - 1]);
		FSE_initCState2(&stateLitLength, CTable_LitLength, llCodeTable[nbSeq - 1]);
		BIT_addBits(&blockStream, sequences[nbSeq - 1].litLength, LL_bits[llCodeTable[nbSeq - 1]]);
		if (ZSTD_32bits())
			BIT_flushBits(&blockStream);
		BIT_addBits(&blockStream, sequences[nbSeq - 1].matchLength, ML_bits[mlCodeTable[nbSeq - 1]]);
		if (ZSTD_32bits())
			BIT_flushBits(&blockStream);
		if (longOffsets) {
			U32 const ofBits = ofCodeTable[nbSeq - 1];
			int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN - 1);
			if (extraBits) {
				BIT_addBits(&blockStream, sequences[nbSeq - 1].offset, extraBits);
				BIT_flushBits(&blockStream);
			}
			BIT_addBits(&blockStream, sequences[nbSeq - 1].offset >> extraBits, ofBits - extraBits);
		} else {
			BIT_addBits(&blockStream, sequences[nbSeq - 1].offset, ofCodeTable[nbSeq - 1]);
		}
		BIT_flushBits(&blockStream);

		{
			size_t n;
			for (n = nbSeq - 2; n < nbSeq; n--) { /* intentional underflow */
				BYTE const llCode = llCodeTable[n];
				BYTE const ofCode = ofCodeTable[n];
				BYTE const mlCode = mlCodeTable[n];
				U32 const llBits = LL_bits[llCode];
				U32 const ofBits = ofCode; /* 32b*/ /* 64b*/
				U32 const mlBits = ML_bits[mlCode];
				/* (7)*/							    /* (7)*/
				FSE_encodeSymbol(&blockStream, &stateOffsetBits, ofCode); /* 15 */  /* 15 */
				FSE_encodeSymbol(&blockStream, &stateMatchLength, mlCode); /* 24 */ /* 24 */
				if (ZSTD_32bits())
					BIT_flushBits(&blockStream);				  /* (7)*/
				FSE_encodeSymbol(&blockStream, &stateLitLength, llCode); /* 16 */ /* 33 */
				if (ZSTD_32bits() || (ofBits + mlBits + llBits >= 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
					BIT_flushBits(&blockStream); /* (7)*/
				BIT_addBits(&blockStream, sequences[n].litLength, llBits);
				if (ZSTD_32bits() && ((llBits + mlBits) > 24))
					BIT_flushBits(&blockStream);
				BIT_addBits(&blockStream, sequences[n].matchLength, mlBits);
				if (ZSTD_32bits())
					BIT_flushBits(&blockStream); /* (7)*/
				if (longOffsets) {
					int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN - 1);
					if (extraBits) {
						BIT_addBits(&blockStream, sequences[n].offset, extraBits);
						BIT_flushBits(&blockStream); /* (7)*/
					}
					BIT_addBits(&blockStream, sequences[n].offset >> extraBits, ofBits - extraBits); /* 31 */
				} else {
					BIT_addBits(&blockStream, sequences[n].offset, ofBits); /* 31 */
				}
				BIT_flushBits(&blockStream); /* (7)*/
			}
		}

		FSE_flushCState(&blockStream, &stateMatchLength);
		FSE_flushCState(&blockStream, &stateOffsetBits);
		FSE_flushCState(&blockStream, &stateLitLength);

		{
			size_t const streamSize = BIT_closeCStream(&blockStream);
			if (streamSize == 0)
				return ERROR(dstSize_tooSmall); /* not enough space */
			op += streamSize;
		}
	}
	return op - ostart;
}

ZSTD_STATIC size_t ZSTD_compressSequences(ZSTD_CCtx *zc, void *dst, size_t dstCapacity, size_t srcSize)
{
	size_t const cSize = ZSTD_compressSequences_internal(zc, dst, dstCapacity);
	size_t const minGain = ZSTD_minGain(srcSize);
	size_t const maxCSize = srcSize - minGain;
	/* If the srcSize <= dstCapacity, then there is enough space to write a
	 * raw uncompressed block. Since we ran out of space, the block must not
	 * be compressible, so fall back to a raw uncompressed block.
	 */
	int const uncompressibleError = cSize == ERROR(dstSize_tooSmall) && srcSize <= dstCapacity;
	int i;

	if (ZSTD_isError(cSize) && !uncompressibleError)
		return cSize;
	if (cSize >= maxCSize || uncompressibleError) {
		zc->flagStaticHufTable = HUF_repeat_none;
		return 0;
	}
	/* confirm repcodes */
	for (i = 0; i < ZSTD_REP_NUM; i++)
		zc->rep[i] = zc->repToConfirm[i];
	return cSize;
}

/*! ZSTD_storeSeq() :
	Store a sequence (literal length, literals, offset code and match length code) into seqStore_t.
	`offsetCode` : distance to match, or 0 == repCode.
	`matchCode` : matchLength - MINMATCH
*/
ZSTD_STATIC void ZSTD_storeSeq(seqStore_t *seqStorePtr, size_t litLength, const void *literals, U32 offsetCode, size_t matchCode)
{
	/* copy Literals */
	ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
	seqStorePtr->lit += litLength;

	/* literal Length */
	if (litLength > 0xFFFF) {
		seqStorePtr->longLengthID = 1;
		seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
	}
	seqStorePtr->sequences[0].litLength = (U16)litLength;

	/* match offset */
	seqStorePtr->sequences[0].offset = offsetCode + 1;

	/* match Length */
	if (matchCode > 0xFFFF) {
		seqStorePtr->longLengthID = 2;
		seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
	}
	seqStorePtr->sequences[0].matchLength = (U16)matchCode;

	seqStorePtr->sequences++;
}

/*-*************************************
*  Match length counter
***************************************/
static unsigned ZSTD_NbCommonBytes(register size_t val)
{
	if (ZSTD_isLittleEndian()) {
		if (ZSTD_64bits()) {
			return (__builtin_ctzll((U64)val) >> 3);
		} else { /* 32 bits */
			return (__builtin_ctz((U32)val) >> 3);
		}
	} else { /* Big Endian CPU */
		if (ZSTD_64bits()) {
			return (__builtin_clzll(val) >> 3);
		} else { /* 32 bits */
			return (__builtin_clz((U32)val) >> 3);
		}
	}
}

static size_t ZSTD_count(const BYTE *pIn, const BYTE *pMatch, const BYTE *const pInLimit)
{
	const BYTE *const pStart = pIn;
	const BYTE *const pInLoopLimit = pInLimit - (sizeof(size_t) - 1);

	while (pIn < pInLoopLimit) {
		size_t const diff = ZSTD_readST(pMatch) ^ ZSTD_readST(pIn);
		if (!diff) {
			pIn += sizeof(size_t);
			pMatch += sizeof(size_t);
			continue;
		}
		pIn += ZSTD_NbCommonBytes(diff);
		return (size_t)(pIn - pStart);
	}
	if (ZSTD_64bits())
		if ((pIn < (pInLimit - 3)) && (ZSTD_read32(pMatch) == ZSTD_read32(pIn))) {
			pIn += 4;
			pMatch += 4;
		}
	if ((pIn < (pInLimit - 1)) && (ZSTD_read16(pMatch) == ZSTD_read16(pIn))) {
		pIn += 2;
		pMatch += 2;
	}
	if ((pIn < pInLimit) && (*pMatch == *pIn))
		pIn++;
	return (size_t)(pIn - pStart);
}

/** ZSTD_count_2segments() :
*   can count match length with `ip` & `match` in 2 different segments.
*   convention : on reaching mEnd, match count continue starting from iStart
*/
static size_t ZSTD_count_2segments(const BYTE *ip, const BYTE *match, const BYTE *iEnd, const BYTE *mEnd, const BYTE *iStart)
{
	const BYTE *const vEnd = MIN(ip + (mEnd - match), iEnd);
	size_t const matchLength = ZSTD_count(ip, match, vEnd);
	if (match + matchLength != mEnd)
		return matchLength;
	return matchLength + ZSTD_count(ip + matchLength, iStart, iEnd);
}

/*-*************************************
*  Hashes
***************************************/
static const U32 prime3bytes = 506832829U;
static U32 ZSTD_hash3(U32 u, U32 h) { return ((u << (32 - 24)) * prime3bytes) >> (32 - h); }
ZSTD_STATIC size_t ZSTD_hash3Ptr(const void *ptr, U32 h) { return ZSTD_hash3(ZSTD_readLE32(ptr), h); } /* only in zstd_opt.h */

static const U32 prime4bytes = 2654435761U;
static U32 ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32 - h); }
static size_t ZSTD_hash4Ptr(const void *ptr, U32 h) { return ZSTD_hash4(ZSTD_read32(ptr), h); }

static const U64 prime5bytes = 889523592379ULL;
static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u << (64 - 40)) * prime5bytes) >> (64 - h)); }
static size_t ZSTD_hash5Ptr(const void *p, U32 h) { return ZSTD_hash5(ZSTD_readLE64(p), h); }

static const U64 prime6bytes = 227718039650203ULL;
static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u << (64 - 48)) * prime6bytes) >> (64 - h)); }
static size_t ZSTD_hash6Ptr(const void *p, U32 h) { return ZSTD_hash6(ZSTD_readLE64(p), h); }

static const U64 prime7bytes = 58295818150454627ULL;
static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u << (64 - 56)) * prime7bytes) >> (64 - h)); }
static size_t ZSTD_hash7Ptr(const void *p, U32 h) { return ZSTD_hash7(ZSTD_readLE64(p), h); }

static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u)*prime8bytes) >> (64 - h)); }
static size_t ZSTD_hash8Ptr(const void *p, U32 h) { return ZSTD_hash8(ZSTD_readLE64(p), h); }

static size_t ZSTD_hashPtr(const void *p, U32 hBits, U32 mls)
{
	switch (mls) {
	// case 3: return ZSTD_hash3Ptr(p, hBits);
	default:
	case 4: return ZSTD_hash4Ptr(p, hBits);
	case 5: return ZSTD_hash5Ptr(p, hBits);
	case 6: return ZSTD_hash6Ptr(p, hBits);
	case 7: return ZSTD_hash7Ptr(p, hBits);
	case 8: return ZSTD_hash8Ptr(p, hBits);
	}
}

/*-*************************************
*  Fast Scan
***************************************/
static void ZSTD_fillHashTable(ZSTD_CCtx *zc, const void *end, const U32 mls)
{
	U32 *const hashTable = zc->hashTable;
	U32 const hBits = zc->params.cParams.hashLog;
	const BYTE *const base = zc->base;
	const BYTE *ip = base + zc->nextToUpdate;
	const BYTE *const iend = ((const BYTE *)end) - HASH_READ_SIZE;
	const size_t fastHashFillStep = 3;

	while (ip <= iend) {
		hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip - base);
		ip += fastHashFillStep;
	}
}

FORCE_INLINE
void ZSTD_compressBlock_fast_generic(ZSTD_CCtx *cctx, const void *src, size_t srcSize, const U32 mls)
{
	U32 *const hashTable = cctx->hashTable;
	U32 const hBits = cctx->params.cParams.hashLog;
	seqStore_t *seqStorePtr = &(cctx->seqStore);
	const BYTE *const base = cctx->base;
	const BYTE *const istart = (const BYTE *)src;
	const BYTE *ip = istart;
	const BYTE *anchor = istart;
	const U32 lowestIndex = cctx->dictLimit;
	const BYTE *const lowest = base + lowestIndex;
	const BYTE *const iend = istart + srcSize;
	const BYTE *const ilimit = iend - HASH_READ_SIZE;
	U32 offset_1 = cctx->rep[0], offset_2 = cctx->rep[1];
	U32 offsetSaved = 0;

	/* init */
	ip += (ip == lowest);
	{
		U32 const maxRep = (U32)(ip - lowest);
		if (offset_2 > maxRep)
			offsetSaved = offset_2, offset_2 = 0;
		if (offset_1 > maxRep)
			offsetSaved = offset_1, offset_1 = 0;
	}

	/* Main Search Loop */
	while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
		size_t mLength;
		size_t const h = ZSTD_hashPtr(ip, hBits, mls);
		U32 const curr = (U32)(ip - base);
		U32 const matchIndex = hashTable[h];
		const BYTE *match = base + matchIndex;
		hashTable[h] = curr; /* update hash table */

		if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) {
			mLength = ZSTD_count(ip + 1 + 4, ip + 1 + 4 - offset_1, iend) + 4;
			ip++;
			ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
		} else {
			U32 offset;
			if ((matchIndex <= lowestIndex) || (ZSTD_read32(match) != ZSTD_read32(ip))) {
				ip += ((ip - anchor) >> g_searchStrength) + 1;
				continue;
			}
			mLength = ZSTD_count(ip + 4, match + 4, iend) + 4;
			offset = (U32)(ip - match);
			while (((ip > anchor) & (match > lowest)) && (ip[-1] == match[-1])) {
				ip--;
				match--;
				mLength++;
			} /* catch up */
			offset_2 = offset_1;
			offset_1 = offset;

			ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
		}

		/* match found */
		ip += mLength;
		anchor = ip;

		if (ip <= ilimit) {
			/* Fill Table */
			hashTable[ZSTD_hashPtr(base + curr + 2, hBits, mls)] = curr + 2; /* here because curr+2 could be > iend-8 */
			hashTable[ZSTD_hashPtr(ip - 2, hBits, mls)] = (U32)(ip - 2 - base);
			/* check immediate repcode */
			while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) {
				/* store sequence */
				size_t const rLength = ZSTD_count(ip + 4, ip + 4 - offset_2, iend) + 4;
				{
					U32 const tmpOff = offset_2;
					offset_2 = offset_1;
					offset_1 = tmpOff;
				} /* swap offset_2 <=> offset_1 */
				hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip - base);
				ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength - MINMATCH);
				ip += rLength;
				anchor = ip;
				continue; /* faster when present ... (?) */
			}
		}
	}

	/* save reps for next block */
	cctx->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
	cctx->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;

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

static void ZSTD_compressBlock_fast(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	const U32 mls = ctx->params.cParams.searchLength;
	switch (mls) {
	default: /* includes case 3 */
	case 4: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 4); return;
	case 5: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 5); return;
	case 6: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 6); return;
	case 7: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 7); return;
	}
}

static void ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 mls)
{
	U32 *hashTable = ctx->hashTable;
	const U32 hBits = ctx->params.cParams.hashLog;
	seqStore_t *seqStorePtr = &(ctx->seqStore);
	const BYTE *const base = ctx->base;
	const BYTE *const dictBase = ctx->dictBase;
	const BYTE *const istart = (const BYTE *)src;
	const BYTE *ip = istart;
	const BYTE *anchor = istart;
	const U32 lowestIndex = ctx->lowLimit;
	const BYTE *const dictStart = dictBase + lowestIndex;
	const U32 dictLimit = ctx->dictLimit;
	const BYTE *const lowPrefixPtr = base + dictLimit;
	const BYTE *const dictEnd = dictBase + dictLimit;
	const BYTE *const iend = istart + srcSize;
	const BYTE *const ilimit = iend - 8;
	U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1];

	/* Search Loop */
	while (ip < ilimit) { /* < instead of <=, because (ip+1) */
		const size_t h = ZSTD_hashPtr(ip, hBits, mls);
		const U32 matchIndex = hashTable[h];
		const BYTE *matchBase = matchIndex < dictLimit ? dictBase : base;
		const BYTE *match = matchBase + matchIndex;
		const U32 curr = (U32)(ip - base);
		const U32 repIndex = curr + 1 - offset_1; /* offset_1 expected <= curr +1 */
		const BYTE *repBase = repIndex < dictLimit ? dictBase : base;
		const BYTE *repMatch = repBase + repIndex;
		size_t mLength;
		hashTable[h] = curr; /* update hash table */

		if ((((U32)((dictLimit - 1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex)) &&
		    (ZSTD_read32(repMatch) == ZSTD_read32(ip + 1))) {
			const BYTE *repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
			mLength = ZSTD_count_2segments(ip + 1 + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repMatchEnd, lowPrefixPtr) + EQUAL_READ32;
			ip++;
			ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
		} else {
			if ((matchIndex < lowestIndex) || (ZSTD_read32(match) != ZSTD_read32(ip))) {
				ip += ((ip - anchor) >> g_searchStrength) + 1;
				continue;
			}
			{
				const BYTE *matchEnd = matchIndex < dictLimit ? dictEnd : iend;
				const BYTE *lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
				U32 offset;
				mLength = ZSTD_count_2segments(ip + EQUAL_READ32, match + EQUAL_READ32, iend, matchEnd, lowPrefixPtr) + EQUAL_READ32;
				while (((ip > anchor) & (match > lowMatchPtr)) && (ip[-1] == match[-1])) {
					ip--;
					match--;
					mLength++;
				} /* catch up */
				offset = curr - matchIndex;
				offset_2 = offset_1;
				offset_1 = offset;
				ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
			}
		}

		/* found a match : store it */
		ip += mLength;
		anchor = ip;

		if (ip <= ilimit) {
			/* Fill Table */
			hashTable[ZSTD_hashPtr(base + curr + 2, hBits, mls)] = curr + 2;
			hashTable[ZSTD_hashPtr(ip - 2, hBits, mls)] = (U32)(ip - 2 - base);
			/* check immediate repcode */
			while (ip <= ilimit) {
				U32 const curr2 = (U32)(ip - base);
				U32 const repIndex2 = curr2 - offset_2;
				const BYTE *repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
				if ((((U32)((dictLimit - 1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */
				    && (ZSTD_read32(repMatch2) == ZSTD_read32(ip))) {
					const BYTE *const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
					size_t repLength2 =
					    ZSTD_count_2segments(ip + EQUAL_READ32, repMatch2 + EQUAL_READ32, iend, repEnd2, lowPrefixPtr) + EQUAL_READ32;
					U32 tmpOffset = offset_2;
					offset_2 = offset_1;
					offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
					ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2 - MINMATCH);
					hashTable[ZSTD_hashPtr(ip, hBits, mls)] = curr2;
					ip += repLength2;
					anchor = ip;
					continue;
				}
				break;
			}
		}
	}

	/* save reps for next block */
	ctx->repToConfirm[0] = offset_1;
	ctx->repToConfirm[1] = offset_2;

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

static void ZSTD_compressBlock_fast_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	U32 const mls = ctx->params.cParams.searchLength;
	switch (mls) {
	default: /* includes case 3 */
	case 4: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 4); return;
	case 5: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 5); return;
	case 6: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 6); return;
	case 7: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 7); return;
	}
}

/*-*************************************
*  Double Fast
***************************************/
static void ZSTD_fillDoubleHashTable(ZSTD_CCtx *cctx, const void *end, const U32 mls)
{
	U32 *const hashLarge = cctx->hashTable;
	U32 const hBitsL = cctx->params.cParams.hashLog;
	U32 *const hashSmall = cctx->chainTable;
	U32 const hBitsS = cctx->params.cParams.chainLog;
	const BYTE *const base = cctx->base;
	const BYTE *ip = base + cctx->nextToUpdate;
	const BYTE *const iend = ((const BYTE *)end) - HASH_READ_SIZE;
	const size_t fastHashFillStep = 3;

	while (ip <= iend) {
		hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base);
		hashLarge[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base);
		ip += fastHashFillStep;
	}
}

FORCE_INLINE
void ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx *cctx, const void *src, size_t srcSize, const U32 mls)
{
	U32 *const hashLong = cctx->hashTable;
	const U32 hBitsL = cctx->params.cParams.hashLog;
	U32 *const hashSmall = cctx->chainTable;
	const U32 hBitsS = cctx->params.cParams.chainLog;
	seqStore_t *seqStorePtr = &(cctx->seqStore);
	const BYTE *const base = cctx->base;
	const BYTE *const istart = (const BYTE *)src;
	const BYTE *ip = istart;
	const BYTE *anchor = istart;
	const U32 lowestIndex = cctx->dictLimit;
	const BYTE *const lowest = base + lowestIndex;
	const BYTE *const iend = istart + srcSize;
	const BYTE *const ilimit = iend - HASH_READ_SIZE;
	U32 offset_1 = cctx->rep[0], offset_2 = cctx->rep[1];
	U32 offsetSaved = 0;

	/* init */
	ip += (ip == lowest);
	{
		U32 const maxRep = (U32)(ip - lowest);
		if (offset_2 > maxRep)
			offsetSaved = offset_2, offset_2 = 0;
		if (offset_1 > maxRep)
			offsetSaved = offset_1, offset_1 = 0;
	}

	/* Main Search Loop */
	while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
		size_t mLength;
		size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
		size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
		U32 const curr = (U32)(ip - base);
		U32 const matchIndexL = hashLong[h2];
		U32 const matchIndexS = hashSmall[h];
		const BYTE *matchLong = base + matchIndexL;
		const BYTE *match = base + matchIndexS;
		hashLong[h2] = hashSmall[h] = curr; /* update hash tables */

		if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { /* note : by construction, offset_1 <= curr */
			mLength = ZSTD_count(ip + 1 + 4, ip + 1 + 4 - offset_1, iend) + 4;
			ip++;
			ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
		} else {
			U32 offset;
			if ((matchIndexL > lowestIndex) && (ZSTD_read64(matchLong) == ZSTD_read64(ip))) {
				mLength = ZSTD_count(ip + 8, matchLong + 8, iend) + 8;
				offset = (U32)(ip - matchLong);
				while (((ip > anchor) & (matchLong > lowest)) && (ip[-1] == matchLong[-1])) {
					ip--;
					matchLong--;
					mLength++;
				} /* catch up */
			} else if ((matchIndexS > lowestIndex) && (ZSTD_read32(match) == ZSTD_read32(ip))) {
				size_t const h3 = ZSTD_hashPtr(ip + 1, hBitsL, 8);
				U32 const matchIndex3 = hashLong[h3];
				const BYTE *match3 = base + matchIndex3;
				hashLong[h3] = curr + 1;
				if ((matchIndex3 > lowestIndex) && (ZSTD_read64(match3) == ZSTD_read64(ip + 1))) {
					mLength = ZSTD_count(ip + 9, match3 + 8, iend) + 8;
					ip++;
					offset = (U32)(ip - match3);
					while (((ip > anchor) & (match3 > lowest)) && (ip[-1] == match3[-1])) {
						ip--;
						match3--;
						mLength++;
					} /* catch up */
				} else {
					mLength = ZSTD_count(ip + 4, match + 4, iend) + 4;
					offset = (U32)(ip - match);
					while (((ip > anchor) & (match > lowest)) && (ip[-1] == match[-1])) {
						ip--;
						match--;
						mLength++;
					} /* catch up */
				}
			} else {
				ip += ((ip - anchor) >> g_searchStrength) + 1;
				continue;
			}

			offset_2 = offset_1;
			offset_1 = offset;

			ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
		}

		/* match found */
		ip += mLength;
		anchor = ip;

		if (ip <= ilimit) {
			/* Fill Table */
			hashLong[ZSTD_hashPtr(base + curr + 2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(base + curr + 2, hBitsS, mls)] =
			    curr + 2; /* here because curr+2 could be > iend-8 */
			hashLong[ZSTD_hashPtr(ip - 2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(ip - 2, hBitsS, mls)] = (U32)(ip - 2 - base);

			/* check immediate repcode */
			while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) {
				/* store sequence */
				size_t const rLength = ZSTD_count(ip + 4, ip + 4 - offset_2, iend) + 4;
				{
					U32 const tmpOff = offset_2;
					offset_2 = offset_1;
					offset_1 = tmpOff;
				} /* swap offset_2 <=> offset_1 */
				hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base);
				hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base);
				ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength - MINMATCH);
				ip += rLength;
				anchor = ip;
				continue; /* faster when present ... (?) */
			}
		}
	}

	/* save reps for next block */
	cctx->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
	cctx->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;

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

static void ZSTD_compressBlock_doubleFast(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	const U32 mls = ctx->params.cParams.searchLength;
	switch (mls) {
	default: /* includes case 3 */
	case 4: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 4); return;
	case 5: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 5); return;
	case 6: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 6); return;
	case 7: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 7); return;
	}
}

static void ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 mls)
{
	U32 *const hashLong = ctx->hashTable;
	U32 const hBitsL = ctx->params.cParams.hashLog;
	U32 *const hashSmall = ctx->chainTable;
	U32 const hBitsS = ctx->params.cParams.chainLog;
	seqStore_t *seqStorePtr = &(ctx->seqStore);
	const BYTE *const base = ctx->base;
	const BYTE *const dictBase = ctx->dictBase;
	const BYTE *const istart = (const BYTE *)src;
	const BYTE *ip = istart;
	const BYTE *anchor = istart;
	const U32 lowestIndex = ctx->lowLimit;
	const BYTE *const dictStart = dictBase + lowestIndex;
	const U32 dictLimit = ctx->dictLimit;
	const BYTE *const lowPrefixPtr = base + dictLimit;
	const BYTE *const dictEnd = dictBase + dictLimit;
	const BYTE *const iend = istart + srcSize;
	const BYTE *const ilimit = iend - 8;
	U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1];

	/* Search Loop */
	while (ip < ilimit) { /* < instead of <=, because (ip+1) */
		const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
		const U32 matchIndex = hashSmall[hSmall];
		const BYTE *matchBase = matchIndex < dictLimit ? dictBase : base;
		const BYTE *match = matchBase + matchIndex;

		const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
		const U32 matchLongIndex = hashLong[hLong];
		const BYTE *matchLongBase = matchLongIndex < dictLimit ? dictBase : base;
		const BYTE *matchLong = matchLongBase + matchLongIndex;

		const U32 curr = (U32)(ip - base);
		const U32 repIndex = curr + 1 - offset_1; /* offset_1 expected <= curr +1 */
		const BYTE *repBase = repIndex < dictLimit ? dictBase : base;
		const BYTE *repMatch = repBase + repIndex;
		size_t mLength;
		hashSmall[hSmall] = hashLong[hLong] = curr; /* update hash table */

		if ((((U32)((dictLimit - 1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex)) &&
		    (ZSTD_read32(repMatch) == ZSTD_read32(ip + 1))) {
			const BYTE *repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
			mLength = ZSTD_count_2segments(ip + 1 + 4, repMatch + 4, iend, repMatchEnd, lowPrefixPtr) + 4;
			ip++;
			ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
		} else {
			if ((matchLongIndex > lowestIndex) && (ZSTD_read64(matchLong) == ZSTD_read64(ip))) {
				const BYTE *matchEnd = matchLongIndex < dictLimit ? dictEnd : iend;
				const BYTE *lowMatchPtr = matchLongIndex < dictLimit ? dictStart : lowPrefixPtr;
				U32 offset;
				mLength = ZSTD_count_2segments(ip + 8, matchLong + 8, iend, matchEnd, lowPrefixPtr) + 8;
				offset = curr - matchLongIndex;
				while (((ip > anchor) & (matchLong > lowMatchPtr)) && (ip[-1] == matchLong[-1])) {
					ip--;
					matchLong--;
					mLength++;
				} /* catch up */
				offset_2 = offset_1;
				offset_1 = offset;
				ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);

			} else if ((matchIndex > lowestIndex) && (ZSTD_read32(match) == ZSTD_read32(ip))) {
				size_t const h3 = ZSTD_hashPtr(ip + 1, hBitsL, 8);
				U32 const matchIndex3 = hashLong[h3];
				const BYTE *const match3Base = matchIndex3 < dictLimit ? dictBase : base;
				const BYTE *match3 = match3Base + matchIndex3;
				U32 offset;
				hashLong[h3] = curr + 1;
				if ((matchIndex3 > lowestIndex) && (ZSTD_read64(match3) == ZSTD_read64(ip + 1))) {
					const BYTE *matchEnd = matchIndex3 < dictLimit ? dictEnd : iend;
					const BYTE *lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr;
					mLength = ZSTD_count_2segments(ip + 9, match3 + 8, iend, matchEnd, lowPrefixPtr) + 8;
					ip++;
					offset = curr + 1 - matchIndex3;
					while (((ip > anchor) & (match3 > lowMatchPtr)) && (ip[-1] == match3[-1])) {
						ip--;
						match3--;
						mLength++;
					} /* catch up */
				} else {
					const BYTE *matchEnd = matchIndex < dictLimit ? dictEnd : iend;
					const BYTE *lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
					mLength = ZSTD_count_2segments(ip + 4, match + 4, iend, matchEnd, lowPrefixPtr) + 4;
					offset = curr - matchIndex;
					while (((ip > anchor) & (match > lowMatchPtr)) && (ip[-1] == match[-1])) {
						ip--;
						match--;
						mLength++;
					} /* catch up */
				}
				offset_2 = offset_1;
				offset_1 = offset;
				ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);

			} else {
				ip += ((ip - anchor) >> g_searchStrength) + 1;
				continue;
			}
		}

		/* found a match : store it */
		ip += mLength;
		anchor = ip;

		if (ip <= ilimit) {
			/* Fill Table */
			hashSmall[ZSTD_hashPtr(base + curr + 2, hBitsS, mls)] = curr + 2;
			hashLong[ZSTD_hashPtr(base + curr + 2, hBitsL, 8)] = curr + 2;
			hashSmall[ZSTD_hashPtr(ip - 2, hBitsS, mls)] = (U32)(ip - 2 - base);
			hashLong[ZSTD_hashPtr(ip - 2, hBitsL, 8)] = (U32)(ip - 2 - base);
			/* check immediate repcode */
			while (ip <= ilimit) {
				U32 const curr2 = (U32)(ip - base);
				U32 const repIndex2 = curr2 - offset_2;
				const BYTE *repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
				if ((((U32)((dictLimit - 1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */
				    && (ZSTD_read32(repMatch2) == ZSTD_read32(ip))) {
					const BYTE *const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
					size_t const repLength2 =
					    ZSTD_count_2segments(ip + EQUAL_READ32, repMatch2 + EQUAL_READ32, iend, repEnd2, lowPrefixPtr) + EQUAL_READ32;
					U32 tmpOffset = offset_2;
					offset_2 = offset_1;
					offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
					ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2 - MINMATCH);
					hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = curr2;
					hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = curr2;
					ip += repLength2;
					anchor = ip;
					continue;
				}
				break;
			}
		}
	}

	/* save reps for next block */
	ctx->repToConfirm[0] = offset_1;
	ctx->repToConfirm[1] = offset_2;

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

static void ZSTD_compressBlock_doubleFast_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	U32 const mls = ctx->params.cParams.searchLength;
	switch (mls) {
	default: /* includes case 3 */
	case 4: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 4); return;
	case 5: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 5); return;
	case 6: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 6); return;
	case 7: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 7); return;
	}
}

/*-*************************************
*  Binary Tree search
***************************************/
/** ZSTD_insertBt1() : add one or multiple positions to tree.
*   ip : assumed <= iend-8 .
*   @return : nb of positions added */
static U32 ZSTD_insertBt1(ZSTD_CCtx *zc, const BYTE *const ip, const U32 mls, const BYTE *const iend, U32 nbCompares, U32 extDict)
{
	U32 *const hashTable = zc->hashTable;
	U32 const hashLog = zc->params.cParams.hashLog;
	size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
	U32 *const bt = zc->chainTable;
	U32 const btLog = zc->params.cParams.chainLog - 1;
	U32 const btMask = (1 << btLog) - 1;
	U32 matchIndex = hashTable[h];
	size_t commonLengthSmaller = 0, commonLengthLarger = 0;
	const BYTE *const base = zc->base;
	const BYTE *const dictBase = zc->dictBase;
	const U32 dictLimit = zc->dictLimit;
	const BYTE *const dictEnd = dictBase + dictLimit;
	const BYTE *const prefixStart = base + dictLimit;
	const BYTE *match;
	const U32 curr = (U32)(ip - base);
	const U32 btLow = btMask >= curr ? 0 : curr - btMask;
	U32 *smallerPtr = bt + 2 * (curr & btMask);
	U32 *largerPtr = smallerPtr + 1;
	U32 dummy32; /* to be nullified at the end */
	U32 const windowLow = zc->lowLimit;
	U32 matchEndIdx = curr + 8;
	size_t bestLength = 8;

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

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

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

		if (matchLength > bestLength) {
			bestLength = matchLength;
			if (matchLength > matchEndIdx - matchIndex)
				matchEndIdx = matchIndex + (U32)matchLength;
		}

		if (ip + matchLength == iend) /* equal : no way to know if inf or sup */
			break;		      /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt the tree */

		if (match[matchLength] < ip[matchLength]) { /* necessarily within correct buffer */
			/* 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;
	if (bestLength > 384)
		return MIN(192, (U32)(bestLength - 384)); /* speed optimization */
	if (matchEndIdx > curr + 8)
		return matchEndIdx - curr - 8;
	return 1;
}

static size_t ZSTD_insertBtAndFindBestMatch(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iend, size_t *offsetPtr, U32 nbCompares, const U32 mls,
					    U32 extDict)
{
	U32 *const hashTable = zc->hashTable;
	U32 const hashLog = zc->params.cParams.hashLog;
	size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
	U32 *const bt = zc->chainTable;
	U32 const btLog = zc->params.cParams.chainLog - 1;
	U32 const btMask = (1 << btLog) - 1;
	U32 matchIndex = hashTable[h];
	size_t commonLengthSmaller = 0, commonLengthLarger = 0;
	const BYTE *const base = zc->base;
	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 curr = (U32)(ip - base);
	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 */
	size_t bestLength = 0;

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

	while (nbCompares-- && (matchIndex > windowLow)) {
		U32 *const 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, iend) + 1;
		} else {
			match = dictBase + matchIndex;
			matchLength += ZSTD_count_2segments(ip + matchLength, match + matchLength, iend, 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;
			if ((4 * (int)(matchLength - bestLength)) > (int)(ZSTD_highbit32(curr - matchIndex + 1) - ZSTD_highbit32((U32)offsetPtr[0] + 1)))
				bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + curr - matchIndex;
			if (ip + matchLength == iend) /* 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;

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

static void ZSTD_updateTree(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iend, const U32 nbCompares, const U32 mls)
{
	const BYTE *const base = zc->base;
	const U32 target = (U32)(ip - base);
	U32 idx = zc->nextToUpdate;

	while (idx < target)
		idx += ZSTD_insertBt1(zc, base + idx, mls, iend, nbCompares, 0);
}

/** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
static size_t ZSTD_BtFindBestMatch(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts, const U32 mls)
{
	if (ip < zc->base + zc->nextToUpdate)
		return 0; /* skipped area */
	ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
	return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
}

static size_t ZSTD_BtFindBestMatch_selectMLS(ZSTD_CCtx *zc, /* Index table will be updated */
					     const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts, const U32 matchLengthSearch)
{
	switch (matchLengthSearch) {
	default: /* includes case 3 */
	case 4: return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
	case 5: return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
	case 7:
	case 6: return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
	}
}

static void ZSTD_updateTree_extDict(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iend, const U32 nbCompares, const U32 mls)
{
	const BYTE *const base = zc->base;
	const U32 target = (U32)(ip - base);
	U32 idx = zc->nextToUpdate;

	while (idx < target)
		idx += ZSTD_insertBt1(zc, base + idx, mls, iend, nbCompares, 1);
}

/** Tree updater, providing best match */
static size_t ZSTD_BtFindBestMatch_extDict(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
					   const U32 mls)
{
	if (ip < zc->base + zc->nextToUpdate)
		return 0; /* skipped area */
	ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
	return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
}

static size_t ZSTD_BtFindBestMatch_selectMLS_extDict(ZSTD_CCtx *zc, /* Index table will be updated */
						     const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
						     const U32 matchLengthSearch)
{
	switch (matchLengthSearch) {
	default: /* includes case 3 */
	case 4: return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
	case 5: return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
	case 7:
	case 6: return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
	}
}

/* *********************************
*  Hash Chain
***********************************/
#define NEXT_IN_CHAIN(d, mask) chainTable[(d)&mask]

/* Update chains up to ip (excluded)
   Assumption : always within prefix (i.e. not within extDict) */
FORCE_INLINE
U32 ZSTD_insertAndFindFirstIndex(ZSTD_CCtx *zc, const BYTE *ip, U32 mls)
{
	U32 *const hashTable = zc->hashTable;
	const U32 hashLog = zc->params.cParams.hashLog;
	U32 *const chainTable = zc->chainTable;
	const U32 chainMask = (1 << zc->params.cParams.chainLog) - 1;
	const BYTE *const base = zc->base;
	const U32 target = (U32)(ip - base);
	U32 idx = zc->nextToUpdate;

	while (idx < target) { /* catch up */
		size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls);
		NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
		hashTable[h] = idx;
		idx++;
	}

	zc->nextToUpdate = target;
	return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
}

/* inlining is important to hardwire a hot branch (template emulation) */
FORCE_INLINE
size_t ZSTD_HcFindBestMatch_generic(ZSTD_CCtx *zc, /* Index table will be updated */
				    const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts, const U32 mls,
				    const U32 extDict)
{
	U32 *const chainTable = zc->chainTable;
	const U32 chainSize = (1 << zc->params.cParams.chainLog);
	const U32 chainMask = chainSize - 1;
	const BYTE *const base = zc->base;
	const BYTE *const dictBase = zc->dictBase;
	const U32 dictLimit = zc->dictLimit;
	const BYTE *const prefixStart = base + dictLimit;
	const BYTE *const dictEnd = dictBase + dictLimit;
	const U32 lowLimit = zc->lowLimit;
	const U32 curr = (U32)(ip - base);
	const U32 minChain = curr > chainSize ? curr - chainSize : 0;
	int nbAttempts = maxNbAttempts;
	size_t ml = EQUAL_READ32 - 1;

	/* HC4 match finder */
	U32 matchIndex = ZSTD_insertAndFindFirstIndex(zc, ip, mls);

	for (; (matchIndex > lowLimit) & (nbAttempts > 0); nbAttempts--) {
		const BYTE *match;
		size_t currMl = 0;
		if ((!extDict) || matchIndex >= dictLimit) {
			match = base + matchIndex;
			if (match[ml] == ip[ml]) /* potentially better */
				currMl = ZSTD_count(ip, match, iLimit);
		} else {
			match = dictBase + matchIndex;
			if (ZSTD_read32(match) == ZSTD_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
				currMl = ZSTD_count_2segments(ip + EQUAL_READ32, match + EQUAL_READ32, iLimit, dictEnd, prefixStart) + EQUAL_READ32;
		}

		/* save best solution */
		if (currMl > ml) {
			ml = currMl;
			*offsetPtr = curr - matchIndex + ZSTD_REP_MOVE;
			if (ip + currMl == iLimit)
				break; /* best possible, and avoid read overflow*/
		}

		if (matchIndex <= minChain)
			break;
		matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
	}

	return ml;
}

FORCE_INLINE size_t ZSTD_HcFindBestMatch_selectMLS(ZSTD_CCtx *zc, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
						   const U32 matchLengthSearch)
{
	switch (matchLengthSearch) {
	default: /* includes case 3 */
	case 4: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 0);
	case 5: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 0);
	case 7:
	case 6: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 0);
	}
}

FORCE_INLINE size_t ZSTD_HcFindBestMatch_extDict_selectMLS(ZSTD_CCtx *zc, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
							   const U32 matchLengthSearch)
{
	switch (matchLengthSearch) {
	default: /* includes case 3 */
	case 4: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 1);
	case 5: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 1);
	case 7:
	case 6: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 1);
	}
}

/* *******************************
*  Common parser - lazy strategy
*********************************/
FORCE_INLINE
void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 searchMethod, const U32 depth)
{
	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 + ctx->dictLimit;

	U32 const maxSearches = 1 << ctx->params.cParams.searchLog;
	U32 const mls = ctx->params.cParams.searchLength;

	typedef size_t (*searchMax_f)(ZSTD_CCtx * zc, const BYTE *ip, const BYTE *iLimit, size_t *offsetPtr, U32 maxNbAttempts, U32 matchLengthSearch);
	searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
	U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1], savedOffset = 0;

	/* init */
	ip += (ip == base);
	ctx->nextToUpdate3 = ctx->nextToUpdate;
	{
		U32 const maxRep = (U32)(ip - base);
		if (offset_2 > maxRep)
			savedOffset = offset_2, offset_2 = 0;
		if (offset_1 > maxRep)
			savedOffset = offset_1, offset_1 = 0;
	}

	/* Match Loop */
	while (ip < ilimit) {
		size_t matchLength = 0;
		size_t offset = 0;
		const BYTE *start = ip + 1;

		/* check repCode */
		if ((offset_1 > 0) & (ZSTD_read32(ip + 1) == ZSTD_read32(ip + 1 - offset_1))) {
			/* repcode : we take it */
			matchLength = ZSTD_count(ip + 1 + EQUAL_READ32, ip + 1 + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32;
			if (depth == 0)
				goto _storeSequence;
		}

		/* first search (depth 0) */
		{
			size_t offsetFound = 99999999;
			size_t const ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
			if (ml2 > matchLength)
				matchLength = ml2, start = ip, offset = offsetFound;
		}

		if (matchLength < EQUAL_READ32) {
			ip += ((ip - anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
			continue;
		}

		/* let's try to find a better solution */
		if (depth >= 1)
			while (ip < ilimit) {
				ip++;
				if ((offset) && ((offset_1 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) {
					size_t const mlRep = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32;
					int const gain2 = (int)(mlRep * 3);
					int const gain1 = (int)(matchLength * 3 - ZSTD_highbit32((U32)offset + 1) + 1);
					if ((mlRep >= EQUAL_READ32) && (gain2 > gain1))
						matchLength = mlRep, offset = 0, start = ip;
				}
				{
					size_t offset2 = 99999999;
					size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
					int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
					int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 4);
					if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
						matchLength = ml2, offset = offset2, start = ip;
						continue; /* search a better one */
					}
				}

				/* let's find an even better one */
				if ((depth == 2) && (ip < ilimit)) {
					ip++;
					if ((offset) && ((offset_1 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) {
						size_t const ml2 = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32;
						int const gain2 = (int)(ml2 * 4);
						int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 1);
						if ((ml2 >= EQUAL_READ32) && (gain2 > gain1))
							matchLength = ml2, offset = 0, start = ip;
					}
					{
						size_t offset2 = 99999999;
						size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
						int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
						int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 7);
						if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
							matchLength = ml2, offset = offset2, start = ip;
							continue;
						}
					}
				}
				break; /* nothing found : store previous solution */
			}

		/* NOTE:
		 * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior.
		 * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which
		 * overflows the pointer, which is undefined behavior.
		 */
		/* catch up */
		if (offset) {
			while ((start > anchor) && (start > base + offset - ZSTD_REP_MOVE) &&
			       (start[-1] == (start-offset+ZSTD_REP_MOVE)[-1])) /* only search for offset within prefix */
			{
				start--;
				matchLength++;
			}
			offset_2 = offset_1;
			offset_1 = (U32)(offset - ZSTD_REP_MOVE);
		}

	/* store sequence */
_storeSequence:
		{
			size_t const litLength = start - anchor;
			ZSTD_storeSeq(seqStorePtr, litLength, anchor, (U32)offset, matchLength - MINMATCH);
			anchor = ip = start + matchLength;
		}

		/* check immediate repcode */
		while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) {
			/* store sequence */
			matchLength = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_2, iend) + EQUAL_READ32;
			offset = offset_2;
			offset_2 = offset_1;
			offset_1 = (U32)offset; /* swap repcodes */
			ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength - MINMATCH);
			ip += matchLength;
			anchor = ip;
			continue; /* faster when present ... (?) */
		}
	}

	/* Save reps for next block */
	ctx->repToConfirm[0] = offset_1 ? offset_1 : savedOffset;
	ctx->repToConfirm[1] = offset_2 ? offset_2 : savedOffset;

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

static void ZSTD_compressBlock_btlazy2(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 1, 2); }

static void ZSTD_compressBlock_lazy2(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 2); }

static void ZSTD_compressBlock_lazy(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 1); }

static void ZSTD_compressBlock_greedy(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 0); }

FORCE_INLINE
void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 searchMethod, const U32 depth)
{
	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 dictLimit = ctx->dictLimit;
	const U32 lowestIndex = ctx->lowLimit;
	const BYTE *const prefixStart = base + dictLimit;
	const BYTE *const dictBase = ctx->dictBase;
	const BYTE *const dictEnd = dictBase + dictLimit;
	const BYTE *const dictStart = dictBase + ctx->lowLimit;

	const U32 maxSearches = 1 << ctx->params.cParams.searchLog;
	const U32 mls = ctx->params.cParams.searchLength;

	typedef size_t (*searchMax_f)(ZSTD_CCtx * zc, const BYTE *ip, const BYTE *iLimit, size_t *offsetPtr, U32 maxNbAttempts, U32 matchLengthSearch);
	searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS_extDict : ZSTD_HcFindBestMatch_extDict_selectMLS;

	U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1];

	/* init */
	ctx->nextToUpdate3 = ctx->nextToUpdate;
	ip += (ip == prefixStart);

	/* Match Loop */
	while (ip < ilimit) {
		size_t matchLength = 0;
		size_t offset = 0;
		const BYTE *start = ip + 1;
		U32 curr = (U32)(ip - base);

		/* check repCode */
		{
			const U32 repIndex = (U32)(curr + 1 - offset_1);
			const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
			const BYTE *const repMatch = repBase + repIndex;
			if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
				if (ZSTD_read32(ip + 1) == ZSTD_read32(repMatch)) {
					/* repcode detected we should take it */
					const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
					matchLength =
					    ZSTD_count_2segments(ip + 1 + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repEnd, prefixStart) + EQUAL_READ32;
					if (depth == 0)
						goto _storeSequence;
				}
		}

		/* first search (depth 0) */
		{
			size_t offsetFound = 99999999;
			size_t const ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
			if (ml2 > matchLength)
				matchLength = ml2, start = ip, offset = offsetFound;
		}

		if (matchLength < EQUAL_READ32) {
			ip += ((ip - anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
			continue;
		}

		/* let's try to find a better solution */
		if (depth >= 1)
			while (ip < ilimit) {
				ip++;
				curr++;
				/* check repCode */
				if (offset) {
					const U32 repIndex = (U32)(curr - offset_1);
					const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
					const BYTE *const repMatch = repBase + repIndex;
					if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
						if (ZSTD_read32(ip) == ZSTD_read32(repMatch)) {
							/* repcode detected */
							const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
							size_t const repLength =
							    ZSTD_count_2segments(ip + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repEnd, prefixStart) +
							    EQUAL_READ32;
							int const gain2 = (int)(repLength * 3);
							int const gain1 = (int)(matchLength * 3 - ZSTD_highbit32((U32)offset + 1) + 1);
							if ((repLength >= EQUAL_READ32) && (gain2 > gain1))
								matchLength = repLength, offset = 0, start = ip;
						}
				}

				/* search match, depth 1 */
				{
					size_t offset2 = 99999999;
					size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
					int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
					int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 4);
					if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
						matchLength = ml2, offset = offset2, start = ip;
						continue; /* search a better one */
					}
				}

				/* let's find an even better one */
				if ((depth == 2) && (ip < ilimit)) {
					ip++;
					curr++;
					/* check repCode */
					if (offset) {
						const U32 repIndex = (U32)(curr - offset_1);
						const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
						const BYTE *const repMatch = repBase + repIndex;
						if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
							if (ZSTD_read32(ip) == ZSTD_read32(repMatch)) {
								/* repcode detected */
								const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
								size_t repLength = ZSTD_count_2segments(ip + EQUAL_READ32, repMatch + EQUAL_READ32, iend,
													repEnd, prefixStart) +
										   EQUAL_READ32;
								int gain2 = (int)(repLength * 4);
								int gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 1);
								if ((repLength >= EQUAL_READ32) && (gain2 > gain1))
									matchLength = repLength, offset = 0, start = ip;
							}
					}

					/* search match, depth 2 */
					{
						size_t offset2 = 99999999;
						size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
						int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
						int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 7);
						if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
							matchLength = ml2, offset = offset2, start = ip;
							continue;
						}
					}
				}
				break; /* nothing found : store previous solution */
			}

		/* catch up */
		if (offset) {
			U32 const matchIndex = (U32)((start - base) - (offset - ZSTD_REP_MOVE));
			const BYTE *match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
			const BYTE *const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
			while ((start > anchor) && (match > mStart) && (start[-1] == match[-1])) {
				start--;
				match--;
				matchLength++;
			} /* catch up */
			offset_2 = offset_1;
			offset_1 = (U32)(offset - ZSTD_REP_MOVE);
		}

	/* store sequence */
	_storeSequence : {
		size_t const litLength = start - anchor;
		ZSTD_storeSeq(seqStorePtr, litLength, anchor, (U32)offset, matchLength - MINMATCH);
		anchor = ip = start + matchLength;
	}

		/* check immediate repcode */
		while (ip <= ilimit) {
			const U32 repIndex = (U32)((ip - base) - offset_2);
			const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
			const BYTE *const repMatch = repBase + repIndex;
			if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
				if (ZSTD_read32(ip) == ZSTD_read32(repMatch)) {
					/* repcode detected we should take it */
					const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
					matchLength =
					    ZSTD_count_2segments(ip + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repEnd, prefixStart) + EQUAL_READ32;
					offset = offset_2;
					offset_2 = offset_1;
					offset_1 = (U32)offset; /* swap offset history */
					ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength - MINMATCH);
					ip += matchLength;
					anchor = ip;
					continue; /* faster when present ... (?) */
				}
			break;
		}
	}

	/* Save reps for next block */
	ctx->repToConfirm[0] = offset_1;
	ctx->repToConfirm[1] = offset_2;

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

void ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 0); }

static void ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 1);
}

static void ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2);
}

static void ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
	ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2);
}

/* The optimal parser */
#include "zstd_opt.h"

static void ZSTD_compressBlock_btopt(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
#ifdef ZSTD_OPT_H_91842398743
	ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0);
#else
	(void)ctx;
	(void)src;
	(void)srcSize;
	return;
#endif
}

static void ZSTD_compressBlock_btopt2(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
#ifdef ZSTD_OPT_H_91842398743
	ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 1);
#else
	(void)ctx;
	(void)src;
	(void)srcSize;
	return;
#endif
}

static void ZSTD_compressBlock_btopt_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
#ifdef ZSTD_OPT_H_91842398743
	ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 0);
#else
	(void)ctx;
	(void)src;
	(void)srcSize;
	return;
#endif
}

static void ZSTD_compressBlock_btopt2_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
{
#ifdef ZSTD_OPT_H_91842398743
	ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 1);
#else
	(void)ctx;
	(void)src;
	(void)srcSize;
	return;
#endif
}

typedef void (*ZSTD_blockCompressor)(ZSTD_CCtx *ctx, const void *src, size_t srcSize);

static ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
{
	static const ZSTD_blockCompressor blockCompressor[2][8] = {
	    {ZSTD_compressBlock_fast, ZSTD_compressBlock_doubleFast, ZSTD_compressBlock_greedy, ZSTD_compressBlock_lazy, ZSTD_compressBlock_lazy2,
	     ZSTD_compressBlock_btlazy2, ZSTD_compressBlock_btopt, ZSTD_compressBlock_btopt2},
	    {ZSTD_compressBlock_fast_extDict, ZSTD_compressBlock_doubleFast_extDict, ZSTD_compressBlock_greedy_extDict, ZSTD_compressBlock_lazy_extDict,
	     ZSTD_compressBlock_lazy2_extDict, ZSTD_compressBlock_btlazy2_extDict, ZSTD_compressBlock_btopt_extDict, ZSTD_compressBlock_btopt2_extDict}};

	return blockCompressor[extDict][(U32)strat];
}

static size_t ZSTD_compressBlock_internal(ZSTD_CCtx *zc, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	ZSTD_blockCompressor const blockCompressor = ZSTD_selectBlockCompressor(zc->params.cParams.strategy, zc->lowLimit < zc->dictLimit);
	const BYTE *const base = zc->base;
	const BYTE *const istart = (const BYTE *)src;
	const U32 curr = (U32)(istart - base);
	if (srcSize < MIN_CBLOCK_SIZE + ZSTD_blockHeaderSize + 1)
		return 0; /* don't even attempt compression below a certain srcSize */
	ZSTD_resetSeqStore(&(zc->seqStore));
	if (curr > zc->nextToUpdate + 384)
		zc->nextToUpdate = curr - MIN(192, (U32)(curr - zc->nextToUpdate - 384)); /* update tree not updated after finding very long rep matches */
	blockCompressor(zc, src, srcSize);
	return ZSTD_compressSequences(zc, dst, dstCapacity, srcSize);
}

/*! ZSTD_compress_generic() :
*   Compress a chunk of data into one or multiple blocks.
*   All blocks will be terminated, all input will be consumed.
*   Function will issue an error if there is not enough `dstCapacity` to hold the compressed content.
*   Frame is supposed already started (header already produced)
*   @return : compressed size, or an error code
*/
static size_t ZSTD_compress_generic(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, U32 lastFrameChunk)
{
	size_t blockSize = cctx->blockSize;
	size_t remaining = srcSize;
	const BYTE *ip = (const BYTE *)src;
	BYTE *const ostart = (BYTE *)dst;
	BYTE *op = ostart;
	U32 const maxDist = 1 << cctx->params.cParams.windowLog;

	if (cctx->params.fParams.checksumFlag && srcSize)
		xxh64_update(&cctx->xxhState, src, srcSize);

	while (remaining) {
		U32 const lastBlock = lastFrameChunk & (blockSize >= remaining);
		size_t cSize;

		if (dstCapacity < ZSTD_blockHeaderSize + MIN_CBLOCK_SIZE)
			return ERROR(dstSize_tooSmall); /* not enough space to store compressed block */
		if (remaining < blockSize)
			blockSize = remaining;

		/* preemptive overflow correction */
		if (cctx->lowLimit > (3U << 29)) {
			U32 const cycleMask = (1 << ZSTD_cycleLog(cctx->params.cParams.hashLog, cctx->params.cParams.strategy)) - 1;
			U32 const curr = (U32)(ip - cctx->base);
			U32 const newCurr = (curr & cycleMask) + (1 << cctx->params.cParams.windowLog);
			U32 const correction = curr - newCurr;
			ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX_64 <= 30);
			ZSTD_reduceIndex(cctx, correction);
			cctx->base += correction;
			cctx->dictBase += correction;
			cctx->lowLimit -= correction;
			cctx->dictLimit -= correction;
			if (cctx->nextToUpdate < correction)
				cctx->nextToUpdate = 0;
			else
				cctx->nextToUpdate -= correction;
		}

		if ((U32)(ip + blockSize - cctx->base) > cctx->loadedDictEnd + maxDist) {
			/* enforce maxDist */
			U32 const newLowLimit = (U32)(ip + blockSize - cctx->base) - maxDist;
			if (cctx->lowLimit < newLowLimit)
				cctx->lowLimit = newLowLimit;
			if (cctx->dictLimit < cctx->lowLimit)
				cctx->dictLimit = cctx->lowLimit;
		}

		cSize = ZSTD_compressBlock_internal(cctx, op + ZSTD_blockHeaderSize, dstCapacity - ZSTD_blockHeaderSize, ip, blockSize);
		if (ZSTD_isError(cSize))
			return cSize;

		if (cSize == 0) { /* block is not compressible */
			U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw) << 1) + (U32)(blockSize << 3);
			if (blockSize + ZSTD_blockHeaderSize > dstCapacity)
				return ERROR(dstSize_tooSmall);
			ZSTD_writeLE32(op, cBlockHeader24); /* no pb, 4th byte will be overwritten */
			memcpy(op + ZSTD_blockHeaderSize, ip, blockSize);
			cSize = ZSTD_blockHeaderSize + blockSize;
		} else {
			U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed) << 1) + (U32)(cSize << 3);
			ZSTD_writeLE24(op, cBlockHeader24);
			cSize += ZSTD_blockHeaderSize;
		}

		remaining -= blockSize;
		dstCapacity -= cSize;
		ip += blockSize;
		op += cSize;
	}

	if (lastFrameChunk && (op > ostart))
		cctx->stage = ZSTDcs_ending;
	return op - ostart;
}

static size_t ZSTD_writeFrameHeader(void *dst, size_t dstCapacity, ZSTD_parameters params, U64 pledgedSrcSize, U32 dictID)
{
	BYTE *const op = (BYTE *)dst;
	U32 const dictIDSizeCode = (dictID > 0) + (dictID >= 256) + (dictID >= 65536); /* 0-3 */
	U32 const checksumFlag = params.fParams.checksumFlag > 0;
	U32 const windowSize = 1U << params.cParams.windowLog;
	U32 const singleSegment = params.fParams.contentSizeFlag && (windowSize >= pledgedSrcSize);
	BYTE const windowLogByte = (BYTE)((params.cParams.windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN) << 3);
	U32 const fcsCode =
	    params.fParams.contentSizeFlag ? (pledgedSrcSize >= 256) + (pledgedSrcSize >= 65536 + 256) + (pledgedSrcSize >= 0xFFFFFFFFU) : 0; /* 0-3 */
	BYTE const frameHeaderDecriptionByte = (BYTE)(dictIDSizeCode + (checksumFlag << 2) + (singleSegment << 5) + (fcsCode << 6));
	size_t pos;

	if (dstCapacity < ZSTD_frameHeaderSize_max)
		return ERROR(dstSize_tooSmall);

	ZSTD_writeLE32(dst, ZSTD_MAGICNUMBER);
	op[4] = frameHeaderDecriptionByte;
	pos = 5;
	if (!singleSegment)
		op[pos++] = windowLogByte;
	switch (dictIDSizeCode) {
	default: /* impossible */
	case 0: break;
	case 1:
		op[pos] = (BYTE)(dictID);
		pos++;
		break;
	case 2:
		ZSTD_writeLE16(op + pos, (U16)dictID);
		pos += 2;
		break;
	case 3:
		ZSTD_writeLE32(op + pos, dictID);
		pos += 4;
		break;
	}
	switch (fcsCode) {
	default: /* impossible */
	case 0:
		if (singleSegment)
			op[pos++] = (BYTE)(pledgedSrcSize);
		break;
	case 1:
		ZSTD_writeLE16(op + pos, (U16)(pledgedSrcSize - 256));
		pos += 2;
		break;
	case 2:
		ZSTD_writeLE32(op + pos, (U32)(pledgedSrcSize));
		pos += 4;
		break;
	case 3:
		ZSTD_writeLE64(op + pos, (U64)(pledgedSrcSize));
		pos += 8;
		break;
	}
	return pos;
}

static size_t ZSTD_compressContinue_internal(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, U32 frame, U32 lastFrameChunk)
{
	const BYTE *const ip = (const BYTE *)src;
	size_t fhSize = 0;

	if (cctx->stage == ZSTDcs_created)
		return ERROR(stage_wrong); /* missing init (ZSTD_compressBegin) */

	if (frame && (cctx->stage == ZSTDcs_init)) {
		fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, cctx->params, cctx->frameContentSize, cctx->dictID);
		if (ZSTD_isError(fhSize))
			return fhSize;
		dstCapacity -= fhSize;
		dst = (char *)dst + fhSize;
		cctx->stage = ZSTDcs_ongoing;
	}

	/* Check if blocks follow each other */
	if (src != cctx->nextSrc) {
		/* not contiguous */
		ptrdiff_t const delta = cctx->nextSrc - ip;
		cctx->lowLimit = cctx->dictLimit;
		cctx->dictLimit = (U32)(cctx->nextSrc - cctx->base);
		cctx->dictBase = cctx->base;
		cctx->base -= delta;
		cctx->nextToUpdate = cctx->dictLimit;
		if (cctx->dictLimit - cctx->lowLimit < HASH_READ_SIZE)
			cctx->lowLimit = cctx->dictLimit; /* too small extDict */
	}

	/* if input and dictionary overlap : reduce dictionary (area presumed modified by input) */
	if ((ip + srcSize > cctx->dictBase + cctx->lowLimit) & (ip < cctx->dictBase + cctx->dictLimit)) {
		ptrdiff_t const highInputIdx = (ip + srcSize) - cctx->dictBase;
		U32 const lowLimitMax = (highInputIdx > (ptrdiff_t)cctx->dictLimit) ? cctx->dictLimit : (U32)highInputIdx;
		cctx->lowLimit = lowLimitMax;
	}

	cctx->nextSrc = ip + srcSize;

	if (srcSize) {
		size_t const cSize = frame ? ZSTD_compress_generic(cctx, dst, dstCapacity, src, srcSize, lastFrameChunk)
					   : ZSTD_compressBlock_internal(cctx, dst, dstCapacity, src, srcSize);
		if (ZSTD_isError(cSize))
			return cSize;
		return cSize + fhSize;
	} else
		return fhSize;
}

size_t ZSTD_compressContinue(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1, 0);
}

size_t ZSTD_getBlockSizeMax(ZSTD_CCtx *cctx) { return MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, 1 << cctx->params.cParams.windowLog); }

size_t ZSTD_compressBlock(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	size_t const blockSizeMax = ZSTD_getBlockSizeMax(cctx);
	if (srcSize > blockSizeMax)
		return ERROR(srcSize_wrong);
	return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 0, 0);
}

/*! ZSTD_loadDictionaryContent() :
 *  @return : 0, or an error code
 */
static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx *zc, const void *src, size_t srcSize)
{
	const BYTE *const ip = (const BYTE *)src;
	const BYTE *const iend = ip + srcSize;

	/* input becomes curr prefix */
	zc->lowLimit = zc->dictLimit;
	zc->dictLimit = (U32)(zc->nextSrc - zc->base);
	zc->dictBase = zc->base;
	zc->base += ip - zc->nextSrc;
	zc->nextToUpdate = zc->dictLimit;
	zc->loadedDictEnd = zc->forceWindow ? 0 : (U32)(iend - zc->base);

	zc->nextSrc = iend;
	if (srcSize <= HASH_READ_SIZE)
		return 0;

	switch (zc->params.cParams.strategy) {
	case ZSTD_fast: ZSTD_fillHashTable(zc, iend, zc->params.cParams.searchLength); break;

	case ZSTD_dfast: ZSTD_fillDoubleHashTable(zc, iend, zc->params.cParams.searchLength); break;

	case ZSTD_greedy:
	case ZSTD_lazy:
	case ZSTD_lazy2:
		if (srcSize >= HASH_READ_SIZE)
			ZSTD_insertAndFindFirstIndex(zc, iend - HASH_READ_SIZE, zc->params.cParams.searchLength);
		break;

	case ZSTD_btlazy2:
	case ZSTD_btopt:
	case ZSTD_btopt2:
		if (srcSize >= HASH_READ_SIZE)
			ZSTD_updateTree(zc, iend - HASH_READ_SIZE, iend, 1 << zc->params.cParams.searchLog, zc->params.cParams.searchLength);
		break;

	default:
		return ERROR(GENERIC); /* strategy doesn't exist; impossible */
	}

	zc->nextToUpdate = (U32)(iend - zc->base);
	return 0;
}

/* Dictionaries that assign zero probability to symbols that show up causes problems
   when FSE encoding.  Refuse dictionaries that assign zero probability to symbols
   that we may encounter during compression.
   NOTE: This behavior is not standard and could be improved in the future. */
static size_t ZSTD_checkDictNCount(short *normalizedCounter, unsigned dictMaxSymbolValue, unsigned maxSymbolValue)
{
	U32 s;
	if (dictMaxSymbolValue < maxSymbolValue)
		return ERROR(dictionary_corrupted);
	for (s = 0; s <= maxSymbolValue; ++s) {
		if (normalizedCounter[s] == 0)
			return ERROR(dictionary_corrupted);
	}
	return 0;
}

/* Dictionary format :
 * See :
 * https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#dictionary-format
 */
/*! ZSTD_loadZstdDictionary() :
 * @return : 0, or an error code
 *  assumptions : magic number supposed already checked
 *                dictSize supposed > 8
 */
static size_t ZSTD_loadZstdDictionary(ZSTD_CCtx *cctx, const void *dict, size_t dictSize)
{
	const BYTE *dictPtr = (const BYTE *)dict;
	const BYTE *const dictEnd = dictPtr + dictSize;
	short offcodeNCount[MaxOff + 1];
	unsigned offcodeMaxValue = MaxOff;

	dictPtr += 4; /* skip magic number */
	cctx->dictID = cctx->params.fParams.noDictIDFlag ? 0 : ZSTD_readLE32(dictPtr);
	dictPtr += 4;

	{
		size_t const hufHeaderSize = HUF_readCTable_wksp(cctx->hufTable, 255, dictPtr, dictEnd - dictPtr, cctx->tmpCounters, sizeof(cctx->tmpCounters));
		if (HUF_isError(hufHeaderSize))
			return ERROR(dictionary_corrupted);
		dictPtr += hufHeaderSize;
	}

	{
		unsigned offcodeLog;
		size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd - dictPtr);
		if (FSE_isError(offcodeHeaderSize))
			return ERROR(dictionary_corrupted);
		if (offcodeLog > OffFSELog)
			return ERROR(dictionary_corrupted);
		/* Defer checking offcodeMaxValue because we need to know the size of the dictionary content */
		CHECK_E(FSE_buildCTable_wksp(cctx->offcodeCTable, offcodeNCount, offcodeMaxValue, offcodeLog, cctx->tmpCounters, sizeof(cctx->tmpCounters)),
			dictionary_corrupted);
		dictPtr += offcodeHeaderSize;
	}

	{
		short matchlengthNCount[MaxML + 1];
		unsigned matchlengthMaxValue = MaxML, matchlengthLog;
		size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd - dictPtr);
		if (FSE_isError(matchlengthHeaderSize))
			return ERROR(dictionary_corrupted);
		if (matchlengthLog > MLFSELog)
			return ERROR(dictionary_corrupted);
		/* Every match length code must have non-zero probability */
		CHECK_F(ZSTD_checkDictNCount(matchlengthNCount, matchlengthMaxValue, MaxML));
		CHECK_E(
		    FSE_buildCTable_wksp(cctx->matchlengthCTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog, cctx->tmpCounters, sizeof(cctx->tmpCounters)),
		    dictionary_corrupted);
		dictPtr += matchlengthHeaderSize;
	}

	{
		short litlengthNCount[MaxLL + 1];
		unsigned litlengthMaxValue = MaxLL, litlengthLog;
		size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd - dictPtr);
		if (FSE_isError(litlengthHeaderSize))
			return ERROR(dictionary_corrupted);
		if (litlengthLog > LLFSELog)
			return ERROR(dictionary_corrupted);
		/* Every literal length code must have non-zero probability */
		CHECK_F(ZSTD_checkDictNCount(litlengthNCount, litlengthMaxValue, MaxLL));
		CHECK_E(FSE_buildCTable_wksp(cctx->litlengthCTable, litlengthNCount, litlengthMaxValue, litlengthLog, cctx->tmpCounters, sizeof(cctx->tmpCounters)),
			dictionary_corrupted);
		dictPtr += litlengthHeaderSize;
	}

	if (dictPtr + 12 > dictEnd)
		return ERROR(dictionary_corrupted);
	cctx->rep[0] = ZSTD_readLE32(dictPtr + 0);
	cctx->rep[1] = ZSTD_readLE32(dictPtr + 4);
	cctx->rep[2] = ZSTD_readLE32(dictPtr + 8);
	dictPtr += 12;

	{
		size_t const dictContentSize = (size_t)(dictEnd - dictPtr);
		U32 offcodeMax = MaxOff;
		if (dictContentSize <= ((U32)-1) - 128 KB) {
			U32 const maxOffset = (U32)dictContentSize + 128 KB; /* The maximum offset that must be supported */
			offcodeMax = ZSTD_highbit32(maxOffset);		     /* Calculate minimum offset code required to represent maxOffset */
		}
		/* All offset values <= dictContentSize + 128 KB must be representable */
		CHECK_F(ZSTD_checkDictNCount(offcodeNCount, offcodeMaxValue, MIN(offcodeMax, MaxOff)));
		/* All repCodes must be <= dictContentSize and != 0*/
		{
			U32 u;
			for (u = 0; u < 3; u++) {
				if (cctx->rep[u] == 0)
					return ERROR(dictionary_corrupted);
				if (cctx->rep[u] > dictContentSize)
					return ERROR(dictionary_corrupted);
			}
		}

		cctx->flagStaticTables = 1;
		cctx->flagStaticHufTable = HUF_repeat_valid;
		return ZSTD_loadDictionaryContent(cctx, dictPtr, dictContentSize);
	}
}

/** ZSTD_compress_insertDictionary() :
*   @return : 0, or an error code */
static size_t ZSTD_compress_insertDictionary(ZSTD_CCtx *cctx, const void *dict, size_t dictSize)
{
	if ((dict == NULL) || (dictSize <= 8))
		return 0;

	/* dict as pure content */
	if ((ZSTD_readLE32(dict) != ZSTD_DICT_MAGIC) || (cctx->forceRawDict))
		return ZSTD_loadDictionaryContent(cctx, dict, dictSize);

	/* dict as zstd dictionary */
	return ZSTD_loadZstdDictionary(cctx, dict, dictSize);
}

/*! ZSTD_compressBegin_internal() :
*   @return : 0, or an error code */
static size_t ZSTD_compressBegin_internal(ZSTD_CCtx *cctx, const void *dict, size_t dictSize, ZSTD_parameters params, U64 pledgedSrcSize)
{
	ZSTD_compResetPolicy_e const crp = dictSize ? ZSTDcrp_fullReset : ZSTDcrp_continue;
	CHECK_F(ZSTD_resetCCtx_advanced(cctx, params, pledgedSrcSize, crp));
	return ZSTD_compress_insertDictionary(cctx, dict, dictSize);
}

/*! ZSTD_compressBegin_advanced() :
*   @return : 0, or an error code */
size_t ZSTD_compressBegin_advanced(ZSTD_CCtx *cctx, const void *dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize)
{
	/* compression parameters verification and optimization */
	CHECK_F(ZSTD_checkCParams(params.cParams));
	return ZSTD_compressBegin_internal(cctx, dict, dictSize, params, pledgedSrcSize);
}

size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx *cctx, const void *dict, size_t dictSize, int compressionLevel)
{
	ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, dictSize);
	return ZSTD_compressBegin_internal(cctx, dict, dictSize, params, 0);
}

size_t ZSTD_compressBegin(ZSTD_CCtx *cctx, int compressionLevel) { return ZSTD_compressBegin_usingDict(cctx, NULL, 0, compressionLevel); }

/*! ZSTD_writeEpilogue() :
*   Ends a frame.
*   @return : nb of bytes written into dst (or an error code) */
static size_t ZSTD_writeEpilogue(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity)
{
	BYTE *const ostart = (BYTE *)dst;
	BYTE *op = ostart;
	size_t fhSize = 0;

	if (cctx->stage == ZSTDcs_created)
		return ERROR(stage_wrong); /* init missing */

	/* special case : empty frame */
	if (cctx->stage == ZSTDcs_init) {
		fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, cctx->params, 0, 0);
		if (ZSTD_isError(fhSize))
			return fhSize;
		dstCapacity -= fhSize;
		op += fhSize;
		cctx->stage = ZSTDcs_ongoing;
	}

	if (cctx->stage != ZSTDcs_ending) {
		/* write one last empty block, make it the "last" block */
		U32 const cBlockHeader24 = 1 /* last block */ + (((U32)bt_raw) << 1) + 0;
		if (dstCapacity < 4)
			return ERROR(dstSize_tooSmall);
		ZSTD_writeLE32(op, cBlockHeader24);
		op += ZSTD_blockHeaderSize;
		dstCapacity -= ZSTD_blockHeaderSize;
	}

	if (cctx->params.fParams.checksumFlag) {
		U32 const checksum = (U32)xxh64_digest(&cctx->xxhState);
		if (dstCapacity < 4)
			return ERROR(dstSize_tooSmall);
		ZSTD_writeLE32(op, checksum);
		op += 4;
	}

	cctx->stage = ZSTDcs_created; /* return to "created but no init" status */
	return op - ostart;
}

size_t ZSTD_compressEnd(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	size_t endResult;
	size_t const cSize = ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1, 1);
	if (ZSTD_isError(cSize))
		return cSize;
	endResult = ZSTD_writeEpilogue(cctx, (char *)dst + cSize, dstCapacity - cSize);
	if (ZSTD_isError(endResult))
		return endResult;
	return cSize + endResult;
}

static size_t ZSTD_compress_internal(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
				     ZSTD_parameters params)
{
	CHECK_F(ZSTD_compressBegin_internal(cctx, dict, dictSize, params, srcSize));
	return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
}

size_t ZSTD_compress_usingDict(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
			       ZSTD_parameters params)
{
	return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
}

size_t ZSTD_compressCCtx(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, ZSTD_parameters params)
{
	return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, NULL, 0, params);
}

/* =====  Dictionary API  ===== */

struct ZSTD_CDict_s {
	void *dictBuffer;
	const void *dictContent;
	size_t dictContentSize;
	ZSTD_CCtx *refContext;
}; /* typedef'd tp ZSTD_CDict within "zstd.h" */

size_t ZSTD_CDictWorkspaceBound(ZSTD_compressionParameters cParams) { return ZSTD_CCtxWorkspaceBound(cParams) + ZSTD_ALIGN(sizeof(ZSTD_CDict)); }

static ZSTD_CDict *ZSTD_createCDict_advanced(const void *dictBuffer, size_t dictSize, unsigned byReference, ZSTD_parameters params, ZSTD_customMem customMem)
{
	if (!customMem.customAlloc || !customMem.customFree)
		return NULL;

	{
		ZSTD_CDict *const cdict = (ZSTD_CDict *)ZSTD_malloc(sizeof(ZSTD_CDict), customMem);
		ZSTD_CCtx *const cctx = ZSTD_createCCtx_advanced(customMem);

		if (!cdict || !cctx) {
			ZSTD_free(cdict, customMem);
			ZSTD_freeCCtx(cctx);
			return NULL;
		}

		if ((byReference) || (!dictBuffer) || (!dictSize)) {
			cdict->dictBuffer = NULL;
			cdict->dictContent = dictBuffer;
		} else {
			void *const internalBuffer = ZSTD_malloc(dictSize, customMem);
			if (!internalBuffer) {
				ZSTD_free(cctx, customMem);
				ZSTD_free(cdict, customMem);
				return NULL;
			}
			memcpy(internalBuffer, dictBuffer, dictSize);
			cdict->dictBuffer = internalBuffer;
			cdict->dictContent = internalBuffer;
		}

		{
			size_t const errorCode = ZSTD_compressBegin_advanced(cctx, cdict->dictContent, dictSize, params, 0);
			if (ZSTD_isError(errorCode)) {
				ZSTD_free(cdict->dictBuffer, customMem);
				ZSTD_free(cdict, customMem);
				ZSTD_freeCCtx(cctx);
				return NULL;
			}
		}

		cdict->refContext = cctx;
		cdict->dictContentSize = dictSize;
		return cdict;
	}
}

ZSTD_CDict *ZSTD_initCDict(const void *dict, size_t dictSize, ZSTD_parameters params, void *workspace, size_t workspaceSize)
{
	ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
	return ZSTD_createCDict_advanced(dict, dictSize, 1, params, stackMem);
}

size_t ZSTD_freeCDict(ZSTD_CDict *cdict)
{
	if (cdict == NULL)
		return 0; /* support free on NULL */
	{
		ZSTD_customMem const cMem = cdict->refContext->customMem;
		ZSTD_freeCCtx(cdict->refContext);
		ZSTD_free(cdict->dictBuffer, cMem);
		ZSTD_free(cdict, cMem);
		return 0;
	}
}

static ZSTD_parameters ZSTD_getParamsFromCDict(const ZSTD_CDict *cdict) { return ZSTD_getParamsFromCCtx(cdict->refContext); }

size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx *cctx, const ZSTD_CDict *cdict, unsigned long long pledgedSrcSize)
{
	if (cdict->dictContentSize)
		CHECK_F(ZSTD_copyCCtx(cctx, cdict->refContext, pledgedSrcSize))
	else {
		ZSTD_parameters params = cdict->refContext->params;
		params.fParams.contentSizeFlag = (pledgedSrcSize > 0);
		CHECK_F(ZSTD_compressBegin_advanced(cctx, NULL, 0, params, pledgedSrcSize));
	}
	return 0;
}

/*! ZSTD_compress_usingCDict() :
*   Compression using a digested Dictionary.
*   Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
*   Note that compression level is decided during dictionary creation */
size_t ZSTD_compress_usingCDict(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const ZSTD_CDict *cdict)
{
	CHECK_F(ZSTD_compressBegin_usingCDict(cctx, cdict, srcSize));

	if (cdict->refContext->params.fParams.contentSizeFlag == 1) {
		cctx->params.fParams.contentSizeFlag = 1;
		cctx->frameContentSize = srcSize;
	} else {
		cctx->params.fParams.contentSizeFlag = 0;
	}

	return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
}

/* ******************************************************************
*  Streaming
********************************************************************/

typedef enum { zcss_init, zcss_load, zcss_flush, zcss_final } ZSTD_cStreamStage;

struct ZSTD_CStream_s {
	ZSTD_CCtx *cctx;
	ZSTD_CDict *cdictLocal;
	const ZSTD_CDict *cdict;
	char *inBuff;
	size_t inBuffSize;
	size_t inToCompress;
	size_t inBuffPos;
	size_t inBuffTarget;
	size_t blockSize;
	char *outBuff;
	size_t outBuffSize;
	size_t outBuffContentSize;
	size_t outBuffFlushedSize;
	ZSTD_cStreamStage stage;
	U32 checksum;
	U32 frameEnded;
	U64 pledgedSrcSize;
	U64 inputProcessed;
	ZSTD_parameters params;
	ZSTD_customMem customMem;
}; /* typedef'd to ZSTD_CStream within "zstd.h" */

size_t ZSTD_CStreamWorkspaceBound(ZSTD_compressionParameters cParams)
{
	size_t const inBuffSize = (size_t)1 << cParams.windowLog;
	size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, inBuffSize);
	size_t const outBuffSize = ZSTD_compressBound(blockSize) + 1;

	return ZSTD_CCtxWorkspaceBound(cParams) + ZSTD_ALIGN(sizeof(ZSTD_CStream)) + ZSTD_ALIGN(inBuffSize) + ZSTD_ALIGN(outBuffSize);
}

ZSTD_CStream *ZSTD_createCStream_advanced(ZSTD_customMem customMem)
{
	ZSTD_CStream *zcs;

	if (!customMem.customAlloc || !customMem.customFree)
		return NULL;

	zcs = (ZSTD_CStream *)ZSTD_malloc(sizeof(ZSTD_CStream), customMem);
	if (zcs == NULL)
		return NULL;
	memset(zcs, 0, sizeof(ZSTD_CStream));
	memcpy(&zcs->customMem, &customMem, sizeof(ZSTD_customMem));
	zcs->cctx = ZSTD_createCCtx_advanced(customMem);
	if (zcs->cctx == NULL) {
		ZSTD_freeCStream(zcs);
		return NULL;
	}
	return zcs;
}

size_t ZSTD_freeCStream(ZSTD_CStream *zcs)
{
	if (zcs == NULL)
		return 0; /* support free on NULL */
	{
		ZSTD_customMem const cMem = zcs->customMem;
		ZSTD_freeCCtx(zcs->cctx);
		zcs->cctx = NULL;
		ZSTD_freeCDict(zcs->cdictLocal);
		zcs->cdictLocal = NULL;
		ZSTD_free(zcs->inBuff, cMem);
		zcs->inBuff = NULL;
		ZSTD_free(zcs->outBuff, cMem);
		zcs->outBuff = NULL;
		ZSTD_free(zcs, cMem);
		return 0;
	}
}

/*======   Initialization   ======*/

size_t ZSTD_CStreamInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }
size_t ZSTD_CStreamOutSize(void) { return ZSTD_compressBound(ZSTD_BLOCKSIZE_ABSOLUTEMAX) + ZSTD_blockHeaderSize + 4 /* 32-bits hash */; }

static size_t ZSTD_resetCStream_internal(ZSTD_CStream *zcs, unsigned long long pledgedSrcSize)
{
	if (zcs->inBuffSize == 0)
		return ERROR(stage_wrong); /* zcs has not been init at least once => can't reset */

	if (zcs->cdict)
		CHECK_F(ZSTD_compressBegin_usingCDict(zcs->cctx, zcs->cdict, pledgedSrcSize))
	else
		CHECK_F(ZSTD_compressBegin_advanced(zcs->cctx, NULL, 0, zcs->params, pledgedSrcSize));

	zcs->inToCompress = 0;
	zcs->inBuffPos = 0;
	zcs->inBuffTarget = zcs->blockSize;
	zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
	zcs->stage = zcss_load;
	zcs->frameEnded = 0;
	zcs->pledgedSrcSize = pledgedSrcSize;
	zcs->inputProcessed = 0;
	return 0; /* ready to go */
}

size_t ZSTD_resetCStream(ZSTD_CStream *zcs, unsigned long long pledgedSrcSize)
{

	zcs->params.fParams.contentSizeFlag = (pledgedSrcSize > 0);

	return ZSTD_resetCStream_internal(zcs, pledgedSrcSize);
}

static size_t ZSTD_initCStream_advanced(ZSTD_CStream *zcs, const void *dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize)
{
	/* allocate buffers */
	{
		size_t const neededInBuffSize = (size_t)1 << params.cParams.windowLog;
		if (zcs->inBuffSize < neededInBuffSize) {
			zcs->inBuffSize = neededInBuffSize;
			ZSTD_free(zcs->inBuff, zcs->customMem);
			zcs->inBuff = (char *)ZSTD_malloc(neededInBuffSize, zcs->customMem);
			if (zcs->inBuff == NULL)
				return ERROR(memory_allocation);
		}
		zcs->blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, neededInBuffSize);
	}
	if (zcs->outBuffSize < ZSTD_compressBound(zcs->blockSize) + 1) {
		zcs->outBuffSize = ZSTD_compressBound(zcs->blockSize) + 1;
		ZSTD_free(zcs->outBuff, zcs->customMem);
		zcs->outBuff = (char *)ZSTD_malloc(zcs->outBuffSize, zcs->customMem);
		if (zcs->outBuff == NULL)
			return ERROR(memory_allocation);
	}

	if (dict && dictSize >= 8) {
		ZSTD_freeCDict(zcs->cdictLocal);
		zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize, 0, params, zcs->customMem);
		if (zcs->cdictLocal == NULL)
			return ERROR(memory_allocation);
		zcs->cdict = zcs->cdictLocal;
	} else
		zcs->cdict = NULL;

	zcs->checksum = params.fParams.checksumFlag > 0;
	zcs->params = params;

	return ZSTD_resetCStream_internal(zcs, pledgedSrcSize);
}

ZSTD_CStream *ZSTD_initCStream(ZSTD_parameters params, unsigned long long pledgedSrcSize, void *workspace, size_t workspaceSize)
{
	ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
	ZSTD_CStream *const zcs = ZSTD_createCStream_advanced(stackMem);
	if (zcs) {
		size_t const code = ZSTD_initCStream_advanced(zcs, NULL, 0, params, pledgedSrcSize);
		if (ZSTD_isError(code)) {
			return NULL;
		}
	}
	return zcs;
}

ZSTD_CStream *ZSTD_initCStream_usingCDict(const ZSTD_CDict *cdict, unsigned long long pledgedSrcSize, void *workspace, size_t workspaceSize)
{
	ZSTD_parameters const params = ZSTD_getParamsFromCDict(cdict);
	ZSTD_CStream *const zcs = ZSTD_initCStream(params, pledgedSrcSize, workspace, workspaceSize);
	if (zcs) {
		zcs->cdict = cdict;
		if (ZSTD_isError(ZSTD_resetCStream_internal(zcs, pledgedSrcSize))) {
			return NULL;
		}
	}
	return zcs;
}

/*======   Compression   ======*/

typedef enum { zsf_gather, zsf_flush, zsf_end } ZSTD_flush_e;

ZSTD_STATIC size_t ZSTD_limitCopy(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
	size_t const length = MIN(dstCapacity, srcSize);
	memcpy(dst, src, length);
	return length;
}

static size_t ZSTD_compressStream_generic(ZSTD_CStream *zcs, void *dst, size_t *dstCapacityPtr, const void *src, size_t *srcSizePtr, ZSTD_flush_e const flush)
{
	U32 someMoreWork = 1;
	const char *const istart = (const char *)src;
	const char *const iend = istart + *srcSizePtr;
	const char *ip = istart;
	char *const ostart = (char *)dst;
	char *const oend = ostart + *dstCapacityPtr;
	char *op = ostart;

	while (someMoreWork) {
		switch (zcs->stage) {
		case zcss_init:
			return ERROR(init_missing); /* call ZBUFF_compressInit() first ! */

		case zcss_load:
			/* complete inBuffer */
			{
				size_t const toLoad = zcs->inBuffTarget - zcs->inBuffPos;
				size_t const loaded = ZSTD_limitCopy(zcs->inBuff + zcs->inBuffPos, toLoad, ip, iend - ip);
				zcs->inBuffPos += loaded;
				ip += loaded;
				if ((zcs->inBuffPos == zcs->inToCompress) || (!flush && (toLoad != loaded))) {
					someMoreWork = 0;
					break; /* not enough input to get a full block : stop there, wait for more */
				}
			}
			/* compress curr block (note : this stage cannot be stopped in the middle) */
			{
				void *cDst;
				size_t cSize;
				size_t const iSize = zcs->inBuffPos - zcs->inToCompress;
				size_t oSize = oend - op;
				if (oSize >= ZSTD_compressBound(iSize))
					cDst = op; /* compress directly into output buffer (avoid flush stage) */
				else
					cDst = zcs->outBuff, oSize = zcs->outBuffSize;
				cSize = (flush == zsf_end) ? ZSTD_compressEnd(zcs->cctx, cDst, oSize, zcs->inBuff + zcs->inToCompress, iSize)
							   : ZSTD_compressContinue(zcs->cctx, cDst, oSize, zcs->inBuff + zcs->inToCompress, iSize);
				if (ZSTD_isError(cSize))
					return cSize;
				if (flush == zsf_end)
					zcs->frameEnded = 1;
				/* prepare next block */
				zcs->inBuffTarget = zcs->inBuffPos + zcs->blockSize;
				if (zcs->inBuffTarget > zcs->inBuffSize)
					zcs->inBuffPos = 0, zcs->inBuffTarget = zcs->blockSize; /* note : inBuffSize >= blockSize */
				zcs->inToCompress = zcs->inBuffPos;
				if (cDst == op) {
					op += cSize;
					break;
				} /* no need to flush */
				zcs->outBuffContentSize = cSize;
				zcs->outBuffFlushedSize = 0;
				zcs->stage = zcss_flush; /* pass-through to flush stage */
			}
			/* fall through */

		case zcss_flush: {
			size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
			size_t const flushed = ZSTD_limitCopy(op, oend - op, zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
			op += flushed;
			zcs->outBuffFlushedSize += flushed;
			if (toFlush != flushed) {
				someMoreWork = 0;
				break;
			} /* dst too small to store flushed data : stop there */
			zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
			zcs->stage = zcss_load;
			break;
		}

		case zcss_final:
			someMoreWork = 0; /* do nothing */
			break;

		default:
			return ERROR(GENERIC); /* impossible */
		}
	}

	*srcSizePtr = ip - istart;
	*dstCapacityPtr = op - ostart;
	zcs->inputProcessed += *srcSizePtr;
	if (zcs->frameEnded)
		return 0;
	{
		size_t hintInSize = zcs->inBuffTarget - zcs->inBuffPos;
		if (hintInSize == 0)
			hintInSize = zcs->blockSize;
		return hintInSize;
	}
}

size_t ZSTD_compressStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output, ZSTD_inBuffer *input)
{
	size_t sizeRead = input->size - input->pos;
	size_t sizeWritten = output->size - output->pos;
	size_t const result =
	    ZSTD_compressStream_generic(zcs, (char *)(output->dst) + output->pos, &sizeWritten, (const char *)(input->src) + input->pos, &sizeRead, zsf_gather);
	input->pos += sizeRead;
	output->pos += sizeWritten;
	return result;
}

/*======   Finalize   ======*/

/*! ZSTD_flushStream() :
*   @return : amount of data remaining to flush */
size_t ZSTD_flushStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output)
{
	size_t srcSize = 0;
	size_t sizeWritten = output->size - output->pos;
	size_t const result = ZSTD_compressStream_generic(zcs, (char *)(output->dst) + output->pos, &sizeWritten, &srcSize,
							  &srcSize, /* use a valid src address instead of NULL */
							  zsf_flush);
	output->pos += sizeWritten;
	if (ZSTD_isError(result))
		return result;
	return zcs->outBuffContentSize - zcs->outBuffFlushedSize; /* remaining to flush */
}

size_t ZSTD_endStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output)
{
	BYTE *const ostart = (BYTE *)(output->dst) + output->pos;
	BYTE *const oend = (BYTE *)(output->dst) + output->size;
	BYTE *op = ostart;

	if ((zcs->pledgedSrcSize) && (zcs->inputProcessed != zcs->pledgedSrcSize))
		return ERROR(srcSize_wrong); /* pledgedSrcSize not respected */

	if (zcs->stage != zcss_final) {
		/* flush whatever remains */
		size_t srcSize = 0;
		size_t sizeWritten = output->size - output->pos;
		size_t const notEnded =
		    ZSTD_compressStream_generic(zcs, ostart, &sizeWritten, &srcSize, &srcSize, zsf_end); /* use a valid src address instead of NULL */
		size_t const remainingToFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
		op += sizeWritten;
		if (remainingToFlush) {
			output->pos += sizeWritten;
			return remainingToFlush + ZSTD_BLOCKHEADERSIZE /* final empty block */ + (zcs->checksum * 4);
		}
		/* create epilogue */
		zcs->stage = zcss_final;
		zcs->outBuffContentSize = !notEnded ? 0 : ZSTD_compressEnd(zcs->cctx, zcs->outBuff, zcs->outBuffSize, NULL,
									   0); /* write epilogue, including final empty block, into outBuff */
	}

	/* flush epilogue */
	{
		size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
		size_t const flushed = ZSTD_limitCopy(op, oend - op, zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
		op += flushed;
		zcs->outBuffFlushedSize += flushed;
		output->pos += op - ostart;
		if (toFlush == flushed)
			zcs->stage = zcss_init; /* end reached */
		return toFlush - flushed;
	}
}

/*-=====  Pre-defined compression levels  =====-*/

#define ZSTD_DEFAULT_CLEVEL 1
#define ZSTD_MAX_CLEVEL 22
int ZSTD_maxCLevel(void) { return ZSTD_MAX_CLEVEL; }

static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEVEL + 1] = {
    {
	/* "default" */
	/* W,  C,  H,  S,  L, TL, strat */
	{18, 12, 12, 1, 7, 16, ZSTD_fast},    /* level  0 - never used */
	{19, 13, 14, 1, 7, 16, ZSTD_fast},    /* level  1 */
	{19, 15, 16, 1, 6, 16, ZSTD_fast},    /* level  2 */
	{20, 16, 17, 1, 5, 16, ZSTD_dfast},   /* level  3.*/
	{20, 18, 18, 1, 5, 16, ZSTD_dfast},   /* level  4.*/
	{20, 15, 18, 3, 5, 16, ZSTD_greedy},  /* level  5 */
	{21, 16, 19, 2, 5, 16, ZSTD_lazy},    /* level  6 */
	{21, 17, 20, 3, 5, 16, ZSTD_lazy},    /* level  7 */
	{21, 18, 20, 3, 5, 16, ZSTD_lazy2},   /* level  8 */
	{21, 20, 20, 3, 5, 16, ZSTD_lazy2},   /* level  9 */
	{21, 19, 21, 4, 5, 16, ZSTD_lazy2},   /* level 10 */
	{22, 20, 22, 4, 5, 16, ZSTD_lazy2},   /* level 11 */
	{22, 20, 22, 5, 5, 16, ZSTD_lazy2},   /* level 12 */
	{22, 21, 22, 5, 5, 16, ZSTD_lazy2},   /* level 13 */
	{22, 21, 22, 6, 5, 16, ZSTD_lazy2},   /* level 14 */
	{22, 21, 21, 5, 5, 16, ZSTD_btlazy2}, /* level 15 */
	{23, 22, 22, 5, 5, 16, ZSTD_btlazy2}, /* level 16 */
	{23, 21, 22, 4, 5, 24, ZSTD_btopt},   /* level 17 */
	{23, 23, 22, 6, 5, 32, ZSTD_btopt},   /* level 18 */
	{23, 23, 22, 6, 3, 48, ZSTD_btopt},   /* level 19 */
	{25, 25, 23, 7, 3, 64, ZSTD_btopt2},  /* level 20 */
	{26, 26, 23, 7, 3, 256, ZSTD_btopt2}, /* level 21 */
	{27, 27, 25, 9, 3, 512, ZSTD_btopt2}, /* level 22 */
    },
    {
	/* for srcSize <= 256 KB */
	/* W,  C,  H,  S,  L,  T, strat */
	{0, 0, 0, 0, 0, 0, ZSTD_fast},	 /* level  0 - not used */
	{18, 13, 14, 1, 6, 8, ZSTD_fast},      /* level  1 */
	{18, 14, 13, 1, 5, 8, ZSTD_dfast},     /* level  2 */
	{18, 16, 15, 1, 5, 8, ZSTD_dfast},     /* level  3 */
	{18, 15, 17, 1, 5, 8, ZSTD_greedy},    /* level  4.*/
	{18, 16, 17, 4, 5, 8, ZSTD_greedy},    /* level  5.*/
	{18, 16, 17, 3, 5, 8, ZSTD_lazy},      /* level  6.*/
	{18, 17, 17, 4, 4, 8, ZSTD_lazy},      /* level  7 */
	{18, 17, 17, 4, 4, 8, ZSTD_lazy2},     /* level  8 */
	{18, 17, 17, 5, 4, 8, ZSTD_lazy2},     /* level  9 */
	{18, 17, 17, 6, 4, 8, ZSTD_lazy2},     /* level 10 */
	{18, 18, 17, 6, 4, 8, ZSTD_lazy2},     /* level 11.*/
	{18, 18, 17, 7, 4, 8, ZSTD_lazy2},     /* level 12.*/
	{18, 19, 17, 6, 4, 8, ZSTD_btlazy2},   /* level 13 */
	{18, 18, 18, 4, 4, 16, ZSTD_btopt},    /* level 14.*/
	{18, 18, 18, 4, 3, 16, ZSTD_btopt},    /* level 15.*/
	{18, 19, 18, 6, 3, 32, ZSTD_btopt},    /* level 16.*/
	{18, 19, 18, 8, 3, 64, ZSTD_btopt},    /* level 17.*/
	{18, 19, 18, 9, 3, 128, ZSTD_btopt},   /* level 18.*/
	{18, 19, 18, 10, 3, 256, ZSTD_btopt},  /* level 19.*/
	{18, 19, 18, 11, 3, 512, ZSTD_btopt2}, /* level 20.*/
	{18, 19, 18, 12, 3, 512, ZSTD_btopt2}, /* level 21.*/
	{18, 19, 18, 13, 3, 512, ZSTD_btopt2}, /* level 22.*/
    },
    {
	/* for srcSize <= 128 KB */
	/* W,  C,  H,  S,  L,  T, strat */
	{17, 12, 12, 1, 7, 8, ZSTD_fast},      /* level  0 - not used */
	{17, 12, 13, 1, 6, 8, ZSTD_fast},      /* level  1 */
	{17, 13, 16, 1, 5, 8, ZSTD_fast},      /* level  2 */
	{17, 16, 16, 2, 5, 8, ZSTD_dfast},     /* level  3 */
	{17, 13, 15, 3, 4, 8, ZSTD_greedy},    /* level  4 */
	{17, 15, 17, 4, 4, 8, ZSTD_greedy},    /* level  5 */
	{17, 16, 17, 3, 4, 8, ZSTD_lazy},      /* level  6 */
	{17, 15, 17, 4, 4, 8, ZSTD_lazy2},     /* level  7 */
	{17, 17, 17, 4, 4, 8, ZSTD_lazy2},     /* level  8 */
	{17, 17, 17, 5, 4, 8, ZSTD_lazy2},     /* level  9 */
	{17, 17, 17, 6, 4, 8, ZSTD_lazy2},     /* level 10 */
	{17, 17, 17, 7, 4, 8, ZSTD_lazy2},     /* level 11 */
	{17, 17, 17, 8, 4, 8, ZSTD_lazy2},     /* level 12 */
	{17, 18, 17, 6, 4, 8, ZSTD_btlazy2},   /* level 13.*/
	{17, 17, 17, 7, 3, 8, ZSTD_btopt},     /* level 14.*/
	{17, 17, 17, 7, 3, 16, ZSTD_btopt},    /* level 15.*/
	{17, 18, 17, 7, 3, 32, ZSTD_btopt},    /* level 16.*/
	{17, 18, 17, 7, 3, 64, ZSTD_btopt},    /* level 17.*/
	{17, 18, 17, 7, 3, 256, ZSTD_btopt},   /* level 18.*/
	{17, 18, 17, 8, 3, 256, ZSTD_btopt},   /* level 19.*/
	{17, 18, 17, 9, 3, 256, ZSTD_btopt2},  /* level 20.*/
	{17, 18, 17, 10, 3, 256, ZSTD_btopt2}, /* level 21.*/
	{17, 18, 17, 11, 3, 512, ZSTD_btopt2}, /* level 22.*/
    },
    {
	/* for srcSize <= 16 KB */
	/* W,  C,  H,  S,  L,  T, strat */
	{14, 12, 12, 1, 7, 6, ZSTD_fast},      /* level  0 - not used */
	{14, 14, 14, 1, 6, 6, ZSTD_fast},      /* level  1 */
	{14, 14, 14, 1, 4, 6, ZSTD_fast},      /* level  2 */
	{14, 14, 14, 1, 4, 6, ZSTD_dfast},     /* level  3.*/
	{14, 14, 14, 4, 4, 6, ZSTD_greedy},    /* level  4.*/
	{14, 14, 14, 3, 4, 6, ZSTD_lazy},      /* level  5.*/
	{14, 14, 14, 4, 4, 6, ZSTD_lazy2},     /* level  6 */
	{14, 14, 14, 5, 4, 6, ZSTD_lazy2},     /* level  7 */
	{14, 14, 14, 6, 4, 6, ZSTD_lazy2},     /* level  8.*/
	{14, 15, 14, 6, 4, 6, ZSTD_btlazy2},   /* level  9.*/
	{14, 15, 14, 3, 3, 6, ZSTD_btopt},     /* level 10.*/
	{14, 15, 14, 6, 3, 8, ZSTD_btopt},     /* level 11.*/
	{14, 15, 14, 6, 3, 16, ZSTD_btopt},    /* level 12.*/
	{14, 15, 14, 6, 3, 24, ZSTD_btopt},    /* level 13.*/
	{14, 15, 15, 6, 3, 48, ZSTD_btopt},    /* level 14.*/
	{14, 15, 15, 6, 3, 64, ZSTD_btopt},    /* level 15.*/
	{14, 15, 15, 6, 3, 96, ZSTD_btopt},    /* level 16.*/
	{14, 15, 15, 6, 3, 128, ZSTD_btopt},   /* level 17.*/
	{14, 15, 15, 6, 3, 256, ZSTD_btopt},   /* level 18.*/
	{14, 15, 15, 7, 3, 256, ZSTD_btopt},   /* level 19.*/
	{14, 15, 15, 8, 3, 256, ZSTD_btopt2},  /* level 20.*/
	{14, 15, 15, 9, 3, 256, ZSTD_btopt2},  /* level 21.*/
	{14, 15, 15, 10, 3, 256, ZSTD_btopt2}, /* level 22.*/
    },
};

/*! ZSTD_getCParams() :
*   @return ZSTD_compressionParameters structure for a selected compression level, `srcSize` and `dictSize`.
*   Size values are optional, provide 0 if not known or unused */
ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long srcSize, size_t dictSize)
{
	ZSTD_compressionParameters cp;
	size_t const addedSize = srcSize ? 0 : 500;
	U64 const rSize = srcSize + dictSize ? srcSize + dictSize + addedSize : (U64)-1;
	U32 const tableID = (rSize <= 256 KB) + (rSize <= 128 KB) + (rSize <= 16 KB); /* intentional underflow for srcSizeHint == 0 */
	if (compressionLevel <= 0)
		compressionLevel = ZSTD_DEFAULT_CLEVEL; /* 0 == default; no negative compressionLevel yet */
	if (compressionLevel > ZSTD_MAX_CLEVEL)
		compressionLevel = ZSTD_MAX_CLEVEL;
	cp = ZSTD_defaultCParameters[tableID][compressionLevel];
	if (ZSTD_32bits()) { /* auto-correction, for 32-bits mode */
		if (cp.windowLog > ZSTD_WINDOWLOG_MAX)
			cp.windowLog = ZSTD_WINDOWLOG_MAX;
		if (cp.chainLog > ZSTD_CHAINLOG_MAX)
			cp.chainLog = ZSTD_CHAINLOG_MAX;
		if (cp.hashLog > ZSTD_HASHLOG_MAX)
			cp.hashLog = ZSTD_HASHLOG_MAX;
	}
	cp = ZSTD_adjustCParams(cp, srcSize, dictSize);
	return cp;
}

/*! ZSTD_getParams() :
*   same as ZSTD_getCParams(), but @return a `ZSTD_parameters` object (instead of `ZSTD_compressionParameters`).
*   All fields of `ZSTD_frameParameters` are set to default (0) */
ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSize, size_t dictSize)
{
	ZSTD_parameters params;
	ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, srcSize, dictSize);
	memset(&params, 0, sizeof(params));
	params.cParams = cParams;
	return params;
}

EXPORT_SYMBOL(ZSTD_maxCLevel);
EXPORT_SYMBOL(ZSTD_compressBound);

EXPORT_SYMBOL(ZSTD_CCtxWorkspaceBound);
EXPORT_SYMBOL(ZSTD_initCCtx);
EXPORT_SYMBOL(ZSTD_compressCCtx);
EXPORT_SYMBOL(ZSTD_compress_usingDict);

EXPORT_SYMBOL(ZSTD_CDictWorkspaceBound);
EXPORT_SYMBOL(ZSTD_initCDict);
EXPORT_SYMBOL(ZSTD_compress_usingCDict);

EXPORT_SYMBOL(ZSTD_CStreamWorkspaceBound);
EXPORT_SYMBOL(ZSTD_initCStream);
EXPORT_SYMBOL(ZSTD_initCStream_usingCDict);
EXPORT_SYMBOL(ZSTD_resetCStream);
EXPORT_SYMBOL(ZSTD_compressStream);
EXPORT_SYMBOL(ZSTD_flushStream);
EXPORT_SYMBOL(ZSTD_endStream);
EXPORT_SYMBOL(ZSTD_CStreamInSize);
EXPORT_SYMBOL(ZSTD_CStreamOutSize);

EXPORT_SYMBOL(ZSTD_getCParams);
EXPORT_SYMBOL(ZSTD_getParams);
EXPORT_SYMBOL(ZSTD_checkCParams);
EXPORT_SYMBOL(ZSTD_adjustCParams);

EXPORT_SYMBOL(ZSTD_compressBegin);
EXPORT_SYMBOL(ZSTD_compressBegin_usingDict);
EXPORT_SYMBOL(ZSTD_compressBegin_advanced);
EXPORT_SYMBOL(ZSTD_copyCCtx);
EXPORT_SYMBOL(ZSTD_compressBegin_usingCDict);
EXPORT_SYMBOL(ZSTD_compressContinue);
EXPORT_SYMBOL(ZSTD_compressEnd);

EXPORT_SYMBOL(ZSTD_getBlockSizeMax);
EXPORT_SYMBOL(ZSTD_compressBlock);

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("Zstd Compressor");