/* LzFind.c -- Match finder for LZ algorithms
2009-04-22 : Igor Pavlov : Public domain */

#include <string.h>

#include "LzFind.h"
#include "LzHash.h"

#define kEmptyHashValue 0
#define kMaxValForNormalize ((UInt32)0xFFFFFFFF)
#define kNormalizeStepMin (1 << 10) /* it must be power of 2 */
#define kNormalizeMask (~(kNormalizeStepMin - 1))
#define kMaxHistorySize ((UInt32)3 << 30)

#define kStartMaxLen 3

static void LzInWindow_Free(CMatchFinder *p, ISzAlloc *alloc)
{
    if (!p->directInput)
    {
        alloc->Free(alloc, p->bufferBase);
        p->bufferBase = 0;
    }
}

/* keepSizeBefore + keepSizeAfter + keepSizeReserv must be < 4G) */

static int LzInWindow_Create(CMatchFinder *p, UInt32 keepSizeReserv, ISzAlloc *alloc)
{
    UInt32 blockSize = p->keepSizeBefore + p->keepSizeAfter + keepSizeReserv;
    if (p->directInput)
    {
        p->blockSize = blockSize;
        return 1;
    }
    if (p->bufferBase == 0 || p->blockSize != blockSize)
    {
        LzInWindow_Free(p, alloc);
        p->blockSize = blockSize;
        p->bufferBase = (Byte *)alloc->Alloc(alloc, (size_t)blockSize);
    }
    return (p->bufferBase != 0);
}

Byte *MatchFinder_GetPointerToCurrentPos(CMatchFinder *p) { return p->buffer; }
Byte MatchFinder_GetIndexByte(CMatchFinder *p, Int32 index) { return p->buffer[index]; }

UInt32 MatchFinder_GetNumAvailableBytes(CMatchFinder *p) { return p->streamPos - p->pos; }

void MatchFinder_ReduceOffsets(CMatchFinder *p, UInt32 subValue)
{
    p->posLimit -= subValue;
    p->pos -= subValue;
    p->streamPos -= subValue;
}

static void MatchFinder_ReadBlock(CMatchFinder *p)
{
    if (p->streamEndWasReached || p->result != SZ_OK)
        return;
    if (p->directInput)
    {
        UInt32 curSize = 0xFFFFFFFF - p->streamPos;
        if (curSize > p->directInputRem)
            curSize = (UInt32)p->directInputRem;
        p->directInputRem -= curSize;
        p->streamPos += curSize;
        if (p->directInputRem == 0)
            p->streamEndWasReached = 1;
        return;
    }
    for (;;)
    {
        Byte *dest = p->buffer + (p->streamPos - p->pos);
        size_t size = (p->bufferBase + p->blockSize - dest);
        if (size == 0)
            return;
        p->result = p->stream->Read(p->stream, dest, &size);
        if (p->result != SZ_OK)
            return;
        if (size == 0)
        {
            p->streamEndWasReached = 1;
            return;
        }
        p->streamPos += (UInt32)size;
        if (p->streamPos - p->pos > p->keepSizeAfter)
            return;
    }
}

void MatchFinder_MoveBlock(CMatchFinder *p)
{
    memmove(p->bufferBase,
        p->buffer - p->keepSizeBefore,
        (size_t)(p->streamPos - p->pos + p->keepSizeBefore));
    p->buffer = p->bufferBase + p->keepSizeBefore;
}

int MatchFinder_NeedMove(CMatchFinder *p)
{
    if (p->directInput)
        return 0;
    /* if (p->streamEndWasReached) return 0; */
    return ((size_t)(p->bufferBase + p->blockSize - p->buffer) <= p->keepSizeAfter);
}

void MatchFinder_ReadIfRequired(CMatchFinder *p)
{
    if (p->streamEndWasReached)
        return;
    if (p->keepSizeAfter >= p->streamPos - p->pos)
        MatchFinder_ReadBlock(p);
}

static void MatchFinder_CheckAndMoveAndRead(CMatchFinder *p)
{
    if (MatchFinder_NeedMove(p))
        MatchFinder_MoveBlock(p);
    MatchFinder_ReadBlock(p);
}

static void MatchFinder_SetDefaultSettings(CMatchFinder *p)
{
    p->cutValue = 32;
    p->btMode = 1;
    p->numHashBytes = 4;
    p->bigHash = 0;
}

#define kCrcPoly 0xEDB88320

void MatchFinder_Construct(CMatchFinder *p)
{
    UInt32 i;
    p->bufferBase = 0;
    p->directInput = 0;
    p->hash = 0;
    MatchFinder_SetDefaultSettings(p);

    for (i = 0; i < 256; i++)
    {
        UInt32 r = i;
        int j;
        for (j = 0; j < 8; j++)
            r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
        p->crc[i] = r;
    }
}

static void MatchFinder_FreeThisClassMemory(CMatchFinder *p, ISzAlloc *alloc)
{
    alloc->Free(alloc, p->hash);
    p->hash = 0;
}

void MatchFinder_Free(CMatchFinder *p, ISzAlloc *alloc)
{
    MatchFinder_FreeThisClassMemory(p, alloc);
    LzInWindow_Free(p, alloc);
}

static CLzRef* AllocRefs(UInt32 num, ISzAlloc *alloc)
{
    size_t sizeInBytes = (size_t)num * sizeof(CLzRef);
    if (sizeInBytes / sizeof(CLzRef) != num)
        return 0;
    return (CLzRef *)alloc->Alloc(alloc, sizeInBytes);
}

int MatchFinder_Create(CMatchFinder *p, UInt32 historySize,
    UInt32 keepAddBufferBefore, UInt32 matchMaxLen, UInt32 keepAddBufferAfter,
    ISzAlloc *alloc)
{
    UInt32 sizeReserv;
    if (historySize > kMaxHistorySize)
    {
        MatchFinder_Free(p, alloc);
        return 0;
    }
    sizeReserv = historySize >> 1;
    if (historySize > ((UInt32)2 << 30))
        sizeReserv = historySize >> 2;
    sizeReserv += (keepAddBufferBefore + matchMaxLen + keepAddBufferAfter) / 2 + (1 << 19);

    p->keepSizeBefore = historySize + keepAddBufferBefore + 1;
    p->keepSizeAfter = matchMaxLen + keepAddBufferAfter;
    /* we need one additional byte, since we use MoveBlock after pos++ and before dictionary using */
    if (LzInWindow_Create(p, sizeReserv, alloc))
    {
        UInt32 newCyclicBufferSize = historySize + 1;
        UInt32 hs;
        p->matchMaxLen = matchMaxLen;
        {
            p->fixedHashSize = 0;
            if (p->numHashBytes == 2)
                hs = (1 << 16) - 1;
            else
            {
                hs = historySize - 1;
                hs |= (hs >> 1);
                hs |= (hs >> 2);
                hs |= (hs >> 4);
                hs |= (hs >> 8);
                hs >>= 1;
                hs |= 0xFFFF; /* don't change it! It's required for Deflate */
                if (hs > (1 << 24))
                {
                    if (p->numHashBytes == 3)
                        hs = (1 << 24) - 1;
                    else
                        hs >>= 1;
                }
            }
            p->hashMask = hs;
            hs++;
            if (p->numHashBytes > 2) p->fixedHashSize += kHash2Size;
            if (p->numHashBytes > 3) p->fixedHashSize += kHash3Size;
            if (p->numHashBytes > 4) p->fixedHashSize += kHash4Size;
            hs += p->fixedHashSize;
        }

    {
        UInt32 prevSize = p->hashSizeSum + p->numSons;
        UInt32 newSize;
        p->historySize = historySize;
        p->hashSizeSum = hs;
        p->cyclicBufferSize = newCyclicBufferSize;
        p->numSons = (p->btMode ? newCyclicBufferSize * 2 : newCyclicBufferSize);
        newSize = p->hashSizeSum + p->numSons;
        if (p->hash != 0 && prevSize == newSize)
            return 1;
        MatchFinder_FreeThisClassMemory(p, alloc);
        p->hash = AllocRefs(newSize, alloc);
        if (p->hash != 0)
        {
            p->son = p->hash + p->hashSizeSum;
            return 1;
        }
    }
    }
    MatchFinder_Free(p, alloc);
    return 0;
}

static void MatchFinder_SetLimits(CMatchFinder *p)
{
    UInt32 limit = kMaxValForNormalize - p->pos;
    UInt32 limit2 = p->cyclicBufferSize - p->cyclicBufferPos;
    if (limit2 < limit)
        limit = limit2;
    limit2 = p->streamPos - p->pos;
    if (limit2 <= p->keepSizeAfter)
    {
        if (limit2 > 0)
            limit2 = 1;
    }
    else
        limit2 -= p->keepSizeAfter;
    if (limit2 < limit)
        limit = limit2;
    {
        UInt32 lenLimit = p->streamPos - p->pos;
        if (lenLimit > p->matchMaxLen)
            lenLimit = p->matchMaxLen;
        p->lenLimit = lenLimit;
    }
    p->posLimit = p->pos + limit;
}

void MatchFinder_Init(CMatchFinder *p)
{
    UInt32 i;
    for (i = 0; i < p->hashSizeSum; i++)
        p->hash[i] = kEmptyHashValue;
    p->cyclicBufferPos = 0;
    p->buffer = p->bufferBase;
    p->pos = p->streamPos = p->cyclicBufferSize;
    p->result = SZ_OK;
    p->streamEndWasReached = 0;
    MatchFinder_ReadBlock(p);
    MatchFinder_SetLimits(p);
}

static UInt32 MatchFinder_GetSubValue(CMatchFinder *p)
{
    return (p->pos - p->historySize - 1) & kNormalizeMask;
}

void MatchFinder_Normalize3(UInt32 subValue, CLzRef *items, UInt32 numItems)
{
    UInt32 i;
    for (i = 0; i < numItems; i++)
    {
        UInt32 value = items[i];
        if (value <= subValue)
            value = kEmptyHashValue;
        else
            value -= subValue;
        items[i] = value;
    }
}

static void MatchFinder_Normalize(CMatchFinder *p)
{
    UInt32 subValue = MatchFinder_GetSubValue(p);
    MatchFinder_Normalize3(subValue, p->hash, p->hashSizeSum + p->numSons);
    MatchFinder_ReduceOffsets(p, subValue);
}

static void MatchFinder_CheckLimits(CMatchFinder *p)
{
    if (p->pos == kMaxValForNormalize)
        MatchFinder_Normalize(p);
    if (!p->streamEndWasReached && p->keepSizeAfter == p->streamPos - p->pos)
        MatchFinder_CheckAndMoveAndRead(p);
    if (p->cyclicBufferPos == p->cyclicBufferSize)
        p->cyclicBufferPos = 0;
    MatchFinder_SetLimits(p);
}

static UInt32 * Hc_GetMatchesSpec(UInt32 lenLimit, UInt32 curMatch, UInt32 pos, const Byte *cur, CLzRef *son,
    UInt32 _cyclicBufferPos, UInt32 _cyclicBufferSize, UInt32 cutValue,
    UInt32 *distances, UInt32 maxLen)
{
    son[_cyclicBufferPos] = curMatch;
    for (;;)
    {
        UInt32 delta = pos - curMatch;
        if (cutValue-- == 0 || delta >= _cyclicBufferSize)
            return distances;
        {
            const Byte *pb = cur - delta;
            curMatch = son[_cyclicBufferPos - delta + ((delta > _cyclicBufferPos) ? _cyclicBufferSize : 0)];
            if (pb[maxLen] == cur[maxLen] && *pb == *cur)
            {
                UInt32 len = 0;
                while (++len != lenLimit)
                    if (pb[len] != cur[len])
                        break;
                if (maxLen < len)
                {
                    *distances++ = maxLen = len;
                    *distances++ = delta - 1;
                    if (len == lenLimit)
                        return distances;
                }
            }
        }
    }
}

UInt32 * GetMatchesSpec1(UInt32 lenLimit, UInt32 curMatch, UInt32 pos, const Byte *cur, CLzRef *son,
    UInt32 _cyclicBufferPos, UInt32 _cyclicBufferSize, UInt32 cutValue,
    UInt32 *distances, UInt32 maxLen)
{
    CLzRef *ptr0 = son + (_cyclicBufferPos << 1) + 1;
    CLzRef *ptr1 = son + (_cyclicBufferPos << 1);
    UInt32 len0 = 0, len1 = 0;
    for (;;)
    {
        UInt32 delta = pos - curMatch;
        if (cutValue-- == 0 || delta >= _cyclicBufferSize)
        {
            *ptr0 = *ptr1 = kEmptyHashValue;
            return distances;
        }
    {
        CLzRef *pair = son + ((_cyclicBufferPos - delta + ((delta > _cyclicBufferPos) ? _cyclicBufferSize : 0)) << 1);
        const Byte *pb = cur - delta;
        UInt32 len = (len0 < len1 ? len0 : len1);
        if (pb[len] == cur[len])
        {
            if (++len != lenLimit && pb[len] == cur[len])
                while (++len != lenLimit)
                    if (pb[len] != cur[len])
                        break;
            if (maxLen < len)
            {
                *distances++ = maxLen = len;
                *distances++ = delta - 1;
                if (len == lenLimit)
                {
                    *ptr1 = pair[0];
                    *ptr0 = pair[1];
                    return distances;
                }
            }
        }
        if (pb[len] < cur[len])
        {
            *ptr1 = curMatch;
            ptr1 = pair + 1;
            curMatch = *ptr1;
            len1 = len;
        }
        else
        {
            *ptr0 = curMatch;
            ptr0 = pair;
            curMatch = *ptr0;
            len0 = len;
        }
    }
    }
}

static void SkipMatchesSpec(UInt32 lenLimit, UInt32 curMatch, UInt32 pos, const Byte *cur, CLzRef *son,
    UInt32 _cyclicBufferPos, UInt32 _cyclicBufferSize, UInt32 cutValue)
{
    CLzRef *ptr0 = son + (_cyclicBufferPos << 1) + 1;
    CLzRef *ptr1 = son + (_cyclicBufferPos << 1);
    UInt32 len0 = 0, len1 = 0;
    for (;;)
    {
        UInt32 delta = pos - curMatch;
        if (cutValue-- == 0 || delta >= _cyclicBufferSize)
        {
            *ptr0 = *ptr1 = kEmptyHashValue;
            return;
        }
    {
        CLzRef *pair = son + ((_cyclicBufferPos - delta + ((delta > _cyclicBufferPos) ? _cyclicBufferSize : 0)) << 1);
        const Byte *pb = cur - delta;
        UInt32 len = (len0 < len1 ? len0 : len1);
        if (pb[len] == cur[len])
        {
            while (++len != lenLimit)
                if (pb[len] != cur[len])
                    break;
            {
                if (len == lenLimit)
                {
                    *ptr1 = pair[0];
                    *ptr0 = pair[1];
                    return;
                }
            }
        }
        if (pb[len] < cur[len])
        {
            *ptr1 = curMatch;
            ptr1 = pair + 1;
            curMatch = *ptr1;
            len1 = len;
        }
        else
        {
            *ptr0 = curMatch;
            ptr0 = pair;
            curMatch = *ptr0;
            len0 = len;
        }
    }
    }
}

#define MOVE_POS \
  ++p->cyclicBufferPos; \
  p->buffer++; \
  if (++p->pos == p->posLimit) MatchFinder_CheckLimits(p);

#define MOVE_POS_RET MOVE_POS return offset;

static void MatchFinder_MovePos(CMatchFinder *p) { MOVE_POS; }

#define GET_MATCHES_HEADER2(minLen, ret_op) \
  UInt32 lenLimit; UInt32 hashValue; const Byte *cur; UInt32 curMatch; \
  lenLimit = p->lenLimit; { if (lenLimit < minLen) { MatchFinder_MovePos(p); ret_op; }} \
  cur = p->buffer;

#define GET_MATCHES_HEADER(minLen) GET_MATCHES_HEADER2(minLen, return 0)
#define SKIP_HEADER(minLen)        GET_MATCHES_HEADER2(minLen, continue)

#define MF_PARAMS(p) p->pos, p->buffer, p->son, p->cyclicBufferPos, p->cyclicBufferSize, p->cutValue

#define GET_MATCHES_FOOTER(offset, maxLen) \
  offset = (UInt32)(GetMatchesSpec1(lenLimit, curMatch, MF_PARAMS(p), \
  distances + offset, maxLen) - distances); MOVE_POS_RET;

#define SKIP_FOOTER \
  SkipMatchesSpec(lenLimit, curMatch, MF_PARAMS(p)); MOVE_POS;

static UInt32 Bt2_MatchFinder_GetMatches(CMatchFinder *p, UInt32 *distances)
{
    UInt32 offset;
    GET_MATCHES_HEADER(2)
        HASH2_CALC;
    curMatch = p->hash[hashValue];
    p->hash[hashValue] = p->pos;
    offset = 0;
    GET_MATCHES_FOOTER(offset, 1)
}

UInt32 Bt3Zip_MatchFinder_GetMatches(CMatchFinder *p, UInt32 *distances)
{
    UInt32 offset;
    GET_MATCHES_HEADER(3)
        HASH_ZIP_CALC;
    curMatch = p->hash[hashValue];
    p->hash[hashValue] = p->pos;
    offset = 0;
    GET_MATCHES_FOOTER(offset, 2)
}

static UInt32 Bt3_MatchFinder_GetMatches(CMatchFinder *p, UInt32 *distances)
{
    UInt32 hash2Value, delta2, maxLen, offset;
    GET_MATCHES_HEADER(3)

        HASH3_CALC;

    delta2 = p->pos - p->hash[hash2Value];
    curMatch = p->hash[kFix3HashSize + hashValue];

    p->hash[hash2Value] =
        p->hash[kFix3HashSize + hashValue] = p->pos;

    maxLen = 2;
    offset = 0;
    if (delta2 < p->cyclicBufferSize && *(cur - delta2) == *cur)
    {
        for (; maxLen != lenLimit; maxLen++)
            if (cur[(ptrdiff_t)maxLen - delta2] != cur[maxLen])
                break;
        distances[0] = maxLen;
        distances[1] = delta2 - 1;
        offset = 2;
        if (maxLen == lenLimit)
        {
            SkipMatchesSpec(lenLimit, curMatch, MF_PARAMS(p));
            MOVE_POS_RET;
        }
    }
    GET_MATCHES_FOOTER(offset, maxLen)
}

static UInt32 Bt4_MatchFinder_GetMatches(CMatchFinder *p, UInt32 *distances)
{
    UInt32 hash2Value, hash3Value, delta2, delta3, maxLen, offset;
    GET_MATCHES_HEADER(4)

        HASH4_CALC;

    delta2 = p->pos - p->hash[hash2Value];
    delta3 = p->pos - p->hash[kFix3HashSize + hash3Value];
    curMatch = p->hash[kFix4HashSize + hashValue];

    p->hash[hash2Value] =
        p->hash[kFix3HashSize + hash3Value] =
        p->hash[kFix4HashSize + hashValue] = p->pos;

    maxLen = 1;
    offset = 0;
    if (delta2 < p->cyclicBufferSize && *(cur - delta2) == *cur)
    {
        distances[0] = maxLen = 2;
        distances[1] = delta2 - 1;
        offset = 2;
    }
    if (delta2 != delta3 && delta3 < p->cyclicBufferSize && *(cur - delta3) == *cur)
    {
        maxLen = 3;
        distances[offset + 1] = delta3 - 1;
        offset += 2;
        delta2 = delta3;
    }
    if (offset != 0)
    {
        for (; maxLen != lenLimit; maxLen++)
            if (cur[(ptrdiff_t)maxLen - delta2] != cur[maxLen])
                break;
        distances[offset - 2] = maxLen;
        if (maxLen == lenLimit)
        {
            SkipMatchesSpec(lenLimit, curMatch, MF_PARAMS(p));
            MOVE_POS_RET;
        }
    }
    if (maxLen < 3)
        maxLen = 3;
    GET_MATCHES_FOOTER(offset, maxLen)
}

static UInt32 Hc4_MatchFinder_GetMatches(CMatchFinder *p, UInt32 *distances)
{
    UInt32 hash2Value, hash3Value, delta2, delta3, maxLen, offset;
    GET_MATCHES_HEADER(4)

        HASH4_CALC;

    delta2 = p->pos - p->hash[hash2Value];
    delta3 = p->pos - p->hash[kFix3HashSize + hash3Value];
    curMatch = p->hash[kFix4HashSize + hashValue];

    p->hash[hash2Value] =
        p->hash[kFix3HashSize + hash3Value] =
        p->hash[kFix4HashSize + hashValue] = p->pos;

    maxLen = 1;
    offset = 0;
    if (delta2 < p->cyclicBufferSize && *(cur - delta2) == *cur)
    {
        distances[0] = maxLen = 2;
        distances[1] = delta2 - 1;
        offset = 2;
    }
    if (delta2 != delta3 && delta3 < p->cyclicBufferSize && *(cur - delta3) == *cur)
    {
        maxLen = 3;
        distances[offset + 1] = delta3 - 1;
        offset += 2;
        delta2 = delta3;
    }
    if (offset != 0)
    {
        for (; maxLen != lenLimit; maxLen++)
            if (cur[(ptrdiff_t)maxLen - delta2] != cur[maxLen])
                break;
        distances[offset - 2] = maxLen;
        if (maxLen == lenLimit)
        {
            p->son[p->cyclicBufferPos] = curMatch;
            MOVE_POS_RET;
        }
    }
    if (maxLen < 3)
        maxLen = 3;
    offset = (UInt32)(Hc_GetMatchesSpec(lenLimit, curMatch, MF_PARAMS(p),
        distances + offset, maxLen) - (distances));
    MOVE_POS_RET
}

UInt32 Hc3Zip_MatchFinder_GetMatches(CMatchFinder *p, UInt32 *distances)
{
    UInt32 offset;
    GET_MATCHES_HEADER(3)
        HASH_ZIP_CALC;
    curMatch = p->hash[hashValue];
    p->hash[hashValue] = p->pos;
    offset = (UInt32)(Hc_GetMatchesSpec(lenLimit, curMatch, MF_PARAMS(p),
        distances, 2) - (distances));
    MOVE_POS_RET
}

static void Bt2_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
{
    do
    {
        SKIP_HEADER(2)
            HASH2_CALC;
        curMatch = p->hash[hashValue];
        p->hash[hashValue] = p->pos;
        SKIP_FOOTER
    } while (--num != 0);
}

void Bt3Zip_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
{
    do
    {
        SKIP_HEADER(3)
            HASH_ZIP_CALC;
        curMatch = p->hash[hashValue];
        p->hash[hashValue] = p->pos;
        SKIP_FOOTER
    } while (--num != 0);
}

static void Bt3_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
{
    do
    {
        UInt32 hash2Value;
        SKIP_HEADER(3)
            HASH3_CALC;
        curMatch = p->hash[kFix3HashSize + hashValue];
        p->hash[hash2Value] =
            p->hash[kFix3HashSize + hashValue] = p->pos;
        SKIP_FOOTER
    } while (--num != 0);
}

static void Bt4_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
{
    do
    {
        UInt32 hash2Value, hash3Value;
        SKIP_HEADER(4)
            HASH4_CALC;
        curMatch = p->hash[kFix4HashSize + hashValue];
        p->hash[hash2Value] =
            p->hash[kFix3HashSize + hash3Value] = p->pos;
        p->hash[kFix4HashSize + hashValue] = p->pos;
        SKIP_FOOTER
    } while (--num != 0);
}

static void Hc4_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
{
    do
    {
        UInt32 hash2Value, hash3Value;
        SKIP_HEADER(4)
            HASH4_CALC;
        curMatch = p->hash[kFix4HashSize + hashValue];
        p->hash[hash2Value] =
            p->hash[kFix3HashSize + hash3Value] =
            p->hash[kFix4HashSize + hashValue] = p->pos;
        p->son[p->cyclicBufferPos] = curMatch;
        MOVE_POS
    } while (--num != 0);
}

void Hc3Zip_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
{
    do
    {
        SKIP_HEADER(3)
            HASH_ZIP_CALC;
        curMatch = p->hash[hashValue];
        p->hash[hashValue] = p->pos;
        p->son[p->cyclicBufferPos] = curMatch;
        MOVE_POS
    } while (--num != 0);
}

void MatchFinder_CreateVTable(CMatchFinder *p, IMatchFinder *vTable)
{
    vTable->Init = (Mf_Init_Func)MatchFinder_Init;
    vTable->GetIndexByte = (Mf_GetIndexByte_Func)MatchFinder_GetIndexByte;
    vTable->GetNumAvailableBytes = (Mf_GetNumAvailableBytes_Func)MatchFinder_GetNumAvailableBytes;
    vTable->GetPointerToCurrentPos = (Mf_GetPointerToCurrentPos_Func)MatchFinder_GetPointerToCurrentPos;
    if (!p->btMode)
    {
        vTable->GetMatches = (Mf_GetMatches_Func)Hc4_MatchFinder_GetMatches;
        vTable->Skip = (Mf_Skip_Func)Hc4_MatchFinder_Skip;
    }
    else if (p->numHashBytes == 2)
    {
        vTable->GetMatches = (Mf_GetMatches_Func)Bt2_MatchFinder_GetMatches;
        vTable->Skip = (Mf_Skip_Func)Bt2_MatchFinder_Skip;
    }
    else if (p->numHashBytes == 3)
    {
        vTable->GetMatches = (Mf_GetMatches_Func)Bt3_MatchFinder_GetMatches;
        vTable->Skip = (Mf_Skip_Func)Bt3_MatchFinder_Skip;
    }
    else
    {
        vTable->GetMatches = (Mf_GetMatches_Func)Bt4_MatchFinder_GetMatches;
        vTable->Skip = (Mf_Skip_Func)Bt4_MatchFinder_Skip;
    }
}