/*

 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.

 * All rights reserved.

 *

 * This source code is licensed under both the BSD-style license (found in the

 * LICENSE file in the root directory of this source tree) and the GPLv2 (found

 * in the COPYING file in the root directory of this source tree).

 * You may select, at your option, one of the above-listed licenses.

 */

/* This header contains definitions

 * that shall **only** be used by modules within lib/compress.

 */

#ifndef ZSTD_COMPRESS_H

#define ZSTD_COMPRESS_H

/*-*************************************

*  Dependencies

***************************************/

#include "zstd_internal.h"

#ifdef ZSTD_MULTITHREAD

#  include "zstdmt_compress.h"

#endif

#if defined (__cplusplus)

extern "C" {

#endif

/*-*************************************

*  Constants

***************************************/

#define kSearchStrength      8

#define HASH_READ_SIZE       8

#define ZSTD_DUBT_UNSORTED_MARK 1   /* For btlazy2 strategy, index 1 now means "unsorted".

                                       It could be confused for a real successor at index "1", if sorted as larger than its predecessor.

                                       It's not a big deal though : candidate will just be sorted again.

                                       Additionnally, candidate position 1 will be lost.

                                       But candidate 1 cannot hide a large tree of candidates, so it's a minimal loss.

/*-*************************************

*  Context memory management

***************************************/

typedef enum { ZSTDcs_created=0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;

typedef enum { zcss_init=0, zcss_load, zcss_flush } ZSTD_cStreamStage;

typedef struct ZSTD_prefixDict_s {

    const void* dict;

    size_t dictSize;

    ZSTD_dictContentType_e dictContentType;

} ZSTD_prefixDict;

typedef struct {

    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)];

    FSE_repeat offcode_repeatMode;

    FSE_repeat matchlength_repeatMode;

    FSE_repeat litlength_repeatMode;

} ZSTD_entropyCTables_t;

typedef struct {

    U32 off;

    U32 len;

} ZSTD_match_t;

typedef struct {

    int price;

    U32 off;

    U32 mlen;

    U32 litlen;

    U32 rep[ZSTD_REP_NUM];

} ZSTD_optimal_t;

typedef struct {

    /* All tables are allocated inside cctx->workspace by ZSTD_resetCCtx_internal() */

    U32  litSum;                 /* nb of literals */

    U32  litLengthSum;           /* nb of litLength codes */

    U32  matchLengthSum;         /* nb of matchLength codes */

    U32  offCodeSum;             /* nb of offset codes */

} optState_t;

typedef struct {

  ZSTD_entropyCTables_t entropy;

  U32 rep[ZSTD_REP_NUM];

} ZSTD_compressedBlockState_t;

typedef struct {

    BYTE const* nextSrc;    /* next block here to continue on current prefix */

    BYTE const* base;       /* All regular indexes relative to this position */

    BYTE const* dictBase;   /* extDict indexes relative to this position */

    U32 dictLimit;          /* below that point, need extDict */

    U32 lowLimit;           /* below that point, no more data */

} ZSTD_window_t;

    U32* hashTable;

    U32* hashTable3;

    U32* chainTable;

    optState_t opt;         /* optimal parser state */

typedef struct {

    ZSTD_compressedBlockState_t* prevCBlock;

    ZSTD_compressedBlockState_t* nextCBlock;

    ZSTD_matchState_t matchState;

} ZSTD_blockState_t;

typedef struct {

    U32 offset;

    U32 checksum;

} ldmEntry_t;

typedef struct {

    ZSTD_window_t window;   /* State for the window round buffer management */

    ldmEntry_t* hashTable;

    BYTE* bucketOffsets;    /* Next position in bucket to insert entry */

    U64 hashPower;          /* Used to compute the rolling hash.

                             * Depends on ldmParams.minMatchLength */

} ldmState_t;

typedef struct {

    U32 enableLdm;          /* 1 if enable long distance matching */

    U32 hashLog;            /* Log size of hashTable */

    U32 bucketSizeLog;      /* Log bucket size for collision resolution, at most 8 */

    U32 minMatchLength;     /* Minimum match length */

    U32 hashEveryLog;       /* Log number of entries to skip */

    U32 windowLog;          /* Window log for the LDM */

} ldmParams_t;

typedef struct {

    U32 offset;

    U32 litLength;

    U32 matchLength;

} rawSeq;

typedef struct {

  rawSeq* seq;     /* The start of the sequences */

  size_t pos;      /* The position where reading stopped. <= size. */

  size_t size;     /* The number of sequences. <= capacity. */

} rawSeqStore_t;

struct ZSTD_CCtx_params_s {

    ZSTD_format_e format;

    ZSTD_compressionParameters cParams;

    ZSTD_frameParameters fParams;

    int compressionLevel;

    int forceWindow;           /* force back-references to respect limit of

                                * 1<<wLog, even for dictionary */

    /* Multithreading: used to pass parameters to mtctx */

    unsigned nbWorkers;

    unsigned jobSize;

    unsigned overlapSizeLog;

    /* Long distance matching parameters */

    ldmParams_t ldmParams;

    /* Internal use, for createCCtxParams() and freeCCtxParams() only */

    ZSTD_customMem customMem;

};  /* typedef'd to ZSTD_CCtx_params within "zstd.h" */

struct ZSTD_CCtx_s {

    ZSTD_compressionStage_e stage;

    int cParamsChanged;                  /* == 1 if cParams(except wlog) or compression level are changed in requestedParams. Triggers transmission of new params to ZSTDMT (if available) then reset to 0. */

    int bmi2;                            /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */

    ZSTD_CCtx_params requestedParams;

    ZSTD_CCtx_params appliedParams;

    U32   dictID;

    void* workSpace;

    size_t workSpaceSize;

    size_t blockSize;

    unsigned long long pledgedSrcSizePlusOne;  /* this way, 0 (default) == unknown */

    unsigned long long consumedSrcSize;

    unsigned long long producedCSize;

    XXH64_state_t xxhState;

    ZSTD_customMem customMem;

    size_t staticSize;

    seqStore_t seqStore;      /* sequences storage ptrs */

    ldmState_t ldmState;      /* long distance matching state */

    rawSeq* ldmSequences;     /* Storage for the ldm output sequences */

    size_t maxNbLdmSequences;

    rawSeqStore_t externSeqStore; /* Mutable reference to external sequences */

    ZSTD_blockState_t blockState;

    U32* entropyWorkspace;  /* entropy workspace of HUF_WORKSPACE_SIZE bytes */

    /* streaming */

    char*  inBuff;

    size_t inBuffSize;

    size_t inToCompress;

    size_t inBuffPos;

    size_t inBuffTarget;

    char*  outBuff;

    size_t outBuffSize;

    size_t outBuffContentSize;

    size_t outBuffFlushedSize;

    ZSTD_cStreamStage streamStage;

    U32    frameEnded;

    /* Dictionary */

    ZSTD_CDict* cdictLocal;

    const ZSTD_CDict* cdict;

    ZSTD_prefixDict prefixDict;   /* single-usage dictionary */

    /* Multi-threading */

#ifdef ZSTD_MULTITHREAD

    ZSTDMT_CCtx* mtctx;

#endif

};

typedef size_t (*ZSTD_blockCompressor) (

        ZSTD_matchState_t* bs, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],

MEM_STATIC U32 ZSTD_LLcode(U32 litLength)

{

    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 U32 LL_deltaCode = 19;

    return (litLength > 63) ? ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];

}

/* ZSTD_MLcode() :

 * note : mlBase = matchLength - MINMATCH;

 *        because it's the format it's stored in seqStore->sequences */

MEM_STATIC U32 ZSTD_MLcode(U32 mlBase)

{

    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 };

    static const U32 ML_deltaCode = 36;

    return (mlBase > 127) ? ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];

}

/*! ZSTD_storeSeq() :

 *  Store a sequence (literal length, literals, offset code and match length code) into seqStore_t.

 *  `offsetCode` : distance to match + 3 (values 1-3 are repCodes).

 *  `mlBase` : matchLength - MINMATCH

*/

MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const void* literals, U32 offsetCode, size_t mlBase)

{

    static const BYTE* g_start = NULL;

    if (g_start==NULL) g_start = (const BYTE*)literals;  /* note : index only works for compression within a single segment */

    {   U32 const pos = (U32)((const BYTE*)literals - g_start);

               pos, (U32)litLength, (U32)mlBase+MINMATCH, (U32)offsetCode);

    }

#endif

    /* copy Literals */

    ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);

    seqStorePtr->lit += litLength;

    /* literal Length */

    if (litLength>0xFFFF) {

        assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */

        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 (mlBase>0xFFFF) {

        assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */

        seqStorePtr->longLengthID = 2;

        seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);

    }

    seqStorePtr->sequences[0].matchLength = (U16)mlBase;

    seqStorePtr->sequences++;

}

/*-*************************************

*  Match length counter

***************************************/

static unsigned ZSTD_NbCommonBytes (size_t val)

{

    if (MEM_isLittleEndian()) {

        if (MEM_64bits()) {

#       if defined(_MSC_VER) && defined(_WIN64)

            unsigned long r = 0;

            _BitScanForward64( &r, (U64)val );

            return (unsigned)(r>>3);

#       elif defined(__GNUC__) && (__GNUC__ >= 4)

            return (__builtin_ctzll((U64)val) >> 3);

#       else

            static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2,

                                                     0, 3, 1, 3, 1, 4, 2, 7,

                                                     0, 2, 3, 6, 1, 5, 3, 5,

                                                     1, 3, 4, 4, 2, 5, 6, 7,

                                                     7, 0, 1, 2, 3, 3, 4, 6,

                                                     2, 6, 5, 5, 3, 4, 5, 6,

                                                     7, 1, 2, 4, 6, 4, 4, 5,

                                                     7, 2, 6, 5, 7, 6, 7, 7 };

            return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];

#       endif

        } else { /* 32 bits */

#       if defined(_MSC_VER)

            unsigned long r=0;

            _BitScanForward( &r, (U32)val );

            return (unsigned)(r>>3);

#       elif defined(__GNUC__) && (__GNUC__ >= 3)

            return (__builtin_ctz((U32)val) >> 3);

#       else

            static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0,

                                                     3, 2, 2, 1, 3, 2, 0, 1,

                                                     3, 3, 1, 2, 2, 2, 2, 0,

                                                     3, 1, 2, 0, 1, 0, 1, 1 };

            return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];

#       endif

        }

    } else {  /* Big Endian CPU */

        if (MEM_64bits()) {

#       if defined(_MSC_VER) && defined(_WIN64)

            unsigned long r = 0;

            _BitScanReverse64( &r, val );

            return (unsigned)(r>>3);

#       elif defined(__GNUC__) && (__GNUC__ >= 4)

            return (__builtin_clzll(val) >> 3);

#       else

            unsigned r;

            const unsigned n32 = sizeof(size_t)*4;   /* calculate this way due to compiler complaining in 32-bits mode */

            if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }

            if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }

            r += (!val);

            return r;

#       endif

        } else { /* 32 bits */

#       if defined(_MSC_VER)

            unsigned long r = 0;

            _BitScanReverse( &r, (unsigned long)val );

            return (unsigned)(r>>3);

#       elif defined(__GNUC__) && (__GNUC__ >= 3)

            return (__builtin_clz((U32)val) >> 3);

#       else

            unsigned r;

            if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }

            r += (!val);

            return r;

#       endif

    }   }

}

MEM_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);

    if (pIn < pInLoopLimit) {

        { size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);

          if (diff) return ZSTD_NbCommonBytes(diff); }

        pIn+=sizeof(size_t); pMatch+=sizeof(size_t);

        while (pIn < pInLoopLimit) {

            size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);

            if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; }

            pIn += ZSTD_NbCommonBytes(diff);

            return (size_t)(pIn - pStart);

    }   }

    if (MEM_64bits() && (pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; }

    if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_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

 */

MEM_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) ; }

MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_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(MEM_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(MEM_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(MEM_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(MEM_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(MEM_readLE64(p), h); }

MEM_STATIC size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls)

{

    switch(mls)

    {

    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);

    }

}

/*-*************************************

*  Round buffer management

***************************************/

/* Max current allowed */

#define ZSTD_CURRENT_MAX ((3U << 29) + (1U << ZSTD_WINDOWLOG_MAX))

/* Maximum chunk size before overflow correction needs to be called again */

#define ZSTD_CHUNKSIZE_MAX                                                     \

    ( ((U32)-1)                  /* Maximum ending current index */            \

    - ZSTD_CURRENT_MAX)          /* Maximum beginning lowLimit */

/**

 * ZSTD_window_clear():

 * Clears the window containing the history by simply setting it to empty.

 */

MEM_STATIC void ZSTD_window_clear(ZSTD_window_t* window)

{

    size_t const endT = (size_t)(window->nextSrc - window->base);

    U32 const end = (U32)endT;

    window->lowLimit = end;

    window->dictLimit = end;