/**
 * 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;
}