OptIO/src/LzFind.c

/* LzFind.c -- Match finder for LZ algorithms
2008-10-04 : 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;
  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->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->skipModeBits = 0; */
  p->directInput = 0;
  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 /* >> p->skipModeBits */) + 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 >>= p->skipModeBits; */
        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;
  }
}
Revision:	1.1
Committed:	Tue Feb 24 20:13:57 2009 UTC (16 years, 2 months ago) by loizides
Content type:	text/plain
Branch:	MAIN
CVS Tags:	Mit_032, Mit_031, Mit_025c_branch2, Mit_025c_branch1, Mit_030, Mit_029c, Mit_030_pre1, Mit_029a, Mit_029, Mit_029_pre1, Mit_028a, Mit_025c_branch0, Mit_028, Mit_027a, Mit_027, Mit_026, Mit_025e, Mit_025d, Mit_025c, Mit_025b, Mit_025a, Mit_025, Mit_025pre2, Mit_024b, Mit_025pre1, Mit_024a, Mit_024, Mit_023, Mit_022a, Mit_022, Mit_020d, TMit_020d, Mit_020c, Mit_021, Mit_021pre2, Mit_021pre1, Mit_020b, Mit_020a, Mit_020, Mit_020pre1, Mit_018, Mit_017, Mit_017pre3, Mit_017pre2, Mit_017pre1, V07-05-00, Mit_016, Mit_015b, Mit_015a, Mit_015, Mit_014e, Mit_014d, Mit_014c, Mit_014b, ConvRejection-10-06-09, Mit_014a, Mit_014, Mit_014pre3, Mit_014pre2, Mit_014pre1, Mit_013d, Mit_013c, Mit_013b, Mit_013a, Mit_013, Mit_013pre1, Mit_012i, Mit_012g, Mit_012f, Mit_012e, Mit_012d, Mit_012c, Mit_012b, Mit_012a, Mit_012, Mit_011a, Mit_011, Mit_010a, Mit_010, Mit_009c, Mit_009b, Mit_009a, Mit_009, Mit_008, Mit_008pre2, Mit_008pre1, HEAD
Branch point for:	Mit_025c_branch
Log Message:	Added lzma
#	User	Rev	Content
1	loizides	1.1	/* LzFind.c -- Match finder for LZ algorithms
2			2008-10-04 : Igor Pavlov : Public domain */
3
4			#include <string.h>
5
6			#include "LzFind.h"
7			#include "LzHash.h"
8
9			#define kEmptyHashValue 0
10			#define kMaxValForNormalize ((UInt32)0xFFFFFFFF)
11			#define kNormalizeStepMin (1 << 10) /* it must be power of 2 */
12			#define kNormalizeMask (~(kNormalizeStepMin - 1))
13			#define kMaxHistorySize ((UInt32)3 << 30)
14
15			#define kStartMaxLen 3
16
17			static void LzInWindow_Free(CMatchFinder p, ISzAlloc alloc)
18			{
19			if (!p->directInput)
20			{
21			alloc->Free(alloc, p->bufferBase);
22			p->bufferBase = 0;
23			}
24			}
25
26			/* keepSizeBefore + keepSizeAfter + keepSizeReserv must be < 4G) */
27
28			static int LzInWindow_Create(CMatchFinder p, UInt32 keepSizeReserv, ISzAlloc alloc)
29			{
30			UInt32 blockSize = p->keepSizeBefore + p->keepSizeAfter + keepSizeReserv;
31			if (p->directInput)
32			{
33			p->blockSize = blockSize;
34			return 1;
35			}
36			if (p->bufferBase == 0 \|\| p->blockSize != blockSize)
37			{
38			LzInWindow_Free(p, alloc);
39			p->blockSize = blockSize;
40			p->bufferBase = (Byte *)alloc->Alloc(alloc, (size_t)blockSize);
41			}
42			return (p->bufferBase != 0);
43			}
44
45			Byte MatchFinder_GetPointerToCurrentPos(CMatchFinder p) { return p->buffer; }
46			Byte MatchFinder_GetIndexByte(CMatchFinder *p, Int32 index) { return p->buffer[index]; }
47
48			UInt32 MatchFinder_GetNumAvailableBytes(CMatchFinder *p) { return p->streamPos - p->pos; }
49
50			void MatchFinder_ReduceOffsets(CMatchFinder *p, UInt32 subValue)
51			{
52			p->posLimit -= subValue;
53			p->pos -= subValue;
54			p->streamPos -= subValue;
55			}
56
57			static void MatchFinder_ReadBlock(CMatchFinder *p)
58			{
59			if (p->streamEndWasReached \|\| p->result != SZ_OK)
60			return;
61			for (;;)
62			{
63			Byte *dest = p->buffer + (p->streamPos - p->pos);
64			size_t size = (p->bufferBase + p->blockSize - dest);
65			if (size == 0)
66			return;
67			p->result = p->stream->Read(p->stream, dest, &size);
68			if (p->result != SZ_OK)
69			return;
70			if (size == 0)
71			{
72			p->streamEndWasReached = 1;
73			return;
74			}
75			p->streamPos += (UInt32)size;
76			if (p->streamPos - p->pos > p->keepSizeAfter)
77			return;
78			}
79			}
80
81			void MatchFinder_MoveBlock(CMatchFinder *p)
82			{
83			memmove(p->bufferBase,
84			p->buffer - p->keepSizeBefore,
85			(size_t)(p->streamPos - p->pos + p->keepSizeBefore));
86			p->buffer = p->bufferBase + p->keepSizeBefore;
87			}
88
89			int MatchFinder_NeedMove(CMatchFinder *p)
90			{
91			/* if (p->streamEndWasReached) return 0; */
92			return ((size_t)(p->bufferBase + p->blockSize - p->buffer) <= p->keepSizeAfter);
93			}
94
95			void MatchFinder_ReadIfRequired(CMatchFinder *p)
96			{
97			if (p->streamEndWasReached)
98			return;
99			if (p->keepSizeAfter >= p->streamPos - p->pos)
100			MatchFinder_ReadBlock(p);
101			}
102
103			static void MatchFinder_CheckAndMoveAndRead(CMatchFinder *p)
104			{
105			if (MatchFinder_NeedMove(p))
106			MatchFinder_MoveBlock(p);
107			MatchFinder_ReadBlock(p);
108			}
109
110			static void MatchFinder_SetDefaultSettings(CMatchFinder *p)
111			{
112			p->cutValue = 32;
113			p->btMode = 1;
114			p->numHashBytes = 4;
115			/* p->skipModeBits = 0; */
116			p->directInput = 0;
117			p->bigHash = 0;
118			}
119
120			#define kCrcPoly 0xEDB88320
121
122			void MatchFinder_Construct(CMatchFinder *p)
123			{
124			UInt32 i;
125			p->bufferBase = 0;
126			p->directInput = 0;
127			p->hash = 0;
128			MatchFinder_SetDefaultSettings(p);
129
130			for (i = 0; i < 256; i++)
131			{
132			UInt32 r = i;
133			int j;
134			for (j = 0; j < 8; j++)
135			r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
136			p->crc[i] = r;
137			}
138			}
139
140			static void MatchFinder_FreeThisClassMemory(CMatchFinder p, ISzAlloc alloc)
141			{
142			alloc->Free(alloc, p->hash);
143			p->hash = 0;
144			}
145
146			void MatchFinder_Free(CMatchFinder p, ISzAlloc alloc)
147			{
148			MatchFinder_FreeThisClassMemory(p, alloc);
149			LzInWindow_Free(p, alloc);
150			}
151
152			static CLzRef* AllocRefs(UInt32 num, ISzAlloc *alloc)
153			{
154			size_t sizeInBytes = (size_t)num * sizeof(CLzRef);
155			if (sizeInBytes / sizeof(CLzRef) != num)
156			return 0;
157			return (CLzRef *)alloc->Alloc(alloc, sizeInBytes);
158			}
159
160			int MatchFinder_Create(CMatchFinder *p, UInt32 historySize,
161			UInt32 keepAddBufferBefore, UInt32 matchMaxLen, UInt32 keepAddBufferAfter,
162			ISzAlloc *alloc)
163			{
164			UInt32 sizeReserv;
165			if (historySize > kMaxHistorySize)
166			{
167			MatchFinder_Free(p, alloc);
168			return 0;
169			}
170			sizeReserv = historySize >> 1;
171			if (historySize > ((UInt32)2 << 30))
172			sizeReserv = historySize >> 2;
173			sizeReserv += (keepAddBufferBefore + matchMaxLen + keepAddBufferAfter) / 2 + (1 << 19);
174
175			p->keepSizeBefore = historySize + keepAddBufferBefore + 1;
176			p->keepSizeAfter = matchMaxLen + keepAddBufferAfter;
177			/* we need one additional byte, since we use MoveBlock after pos++ and before dictionary using */
178			if (LzInWindow_Create(p, sizeReserv, alloc))
179			{
180			UInt32 newCyclicBufferSize = (historySize /* >> p->skipModeBits */) + 1;
181			UInt32 hs;
182			p->matchMaxLen = matchMaxLen;
183			{
184			p->fixedHashSize = 0;
185			if (p->numHashBytes == 2)
186			hs = (1 << 16) - 1;
187			else
188			{
189			hs = historySize - 1;
190			hs \|= (hs >> 1);
191			hs \|= (hs >> 2);
192			hs \|= (hs >> 4);
193			hs \|= (hs >> 8);
194			hs >>= 1;
195			/* hs >>= p->skipModeBits; */
196			hs \|= 0xFFFF; /* don't change it! It's required for Deflate */
197			if (hs > (1 << 24))
198			{
199			if (p->numHashBytes == 3)
200			hs = (1 << 24) - 1;
201			else
202			hs >>= 1;
203			}
204			}
205			p->hashMask = hs;
206			hs++;
207			if (p->numHashBytes > 2) p->fixedHashSize += kHash2Size;
208			if (p->numHashBytes > 3) p->fixedHashSize += kHash3Size;
209			if (p->numHashBytes > 4) p->fixedHashSize += kHash4Size;
210			hs += p->fixedHashSize;
211			}
212
213			{
214			UInt32 prevSize = p->hashSizeSum + p->numSons;
215			UInt32 newSize;
216			p->historySize = historySize;
217			p->hashSizeSum = hs;
218			p->cyclicBufferSize = newCyclicBufferSize;
219			p->numSons = (p->btMode ? newCyclicBufferSize * 2 : newCyclicBufferSize);
220			newSize = p->hashSizeSum + p->numSons;
221			if (p->hash != 0 && prevSize == newSize)
222			return 1;
223			MatchFinder_FreeThisClassMemory(p, alloc);
224			p->hash = AllocRefs(newSize, alloc);
225			if (p->hash != 0)
226			{
227			p->son = p->hash + p->hashSizeSum;
228			return 1;
229			}
230			}
231			}
232			MatchFinder_Free(p, alloc);
233			return 0;
234			}
235
236			static void MatchFinder_SetLimits(CMatchFinder *p)
237			{
238			UInt32 limit = kMaxValForNormalize - p->pos;
239			UInt32 limit2 = p->cyclicBufferSize - p->cyclicBufferPos;
240			if (limit2 < limit)
241			limit = limit2;
242			limit2 = p->streamPos - p->pos;
243			if (limit2 <= p->keepSizeAfter)
244			{
245			if (limit2 > 0)
246			limit2 = 1;
247			}
248			else
249			limit2 -= p->keepSizeAfter;
250			if (limit2 < limit)
251			limit = limit2;
252			{
253			UInt32 lenLimit = p->streamPos - p->pos;
254			if (lenLimit > p->matchMaxLen)
255			lenLimit = p->matchMaxLen;
256			p->lenLimit = lenLimit;
257			}
258			p->posLimit = p->pos + limit;
259			}
260
261			void MatchFinder_Init(CMatchFinder *p)
262			{
263			UInt32 i;
264			for (i = 0; i < p->hashSizeSum; i++)
265			p->hash[i] = kEmptyHashValue;
266			p->cyclicBufferPos = 0;
267			p->buffer = p->bufferBase;
268			p->pos = p->streamPos = p->cyclicBufferSize;
269			p->result = SZ_OK;
270			p->streamEndWasReached = 0;
271			MatchFinder_ReadBlock(p);
272			MatchFinder_SetLimits(p);
273			}
274
275			static UInt32 MatchFinder_GetSubValue(CMatchFinder *p)
276			{
277			return (p->pos - p->historySize - 1) & kNormalizeMask;
278			}
279
280			void MatchFinder_Normalize3(UInt32 subValue, CLzRef *items, UInt32 numItems)
281			{
282			UInt32 i;
283			for (i = 0; i < numItems; i++)
284			{
285			UInt32 value = items[i];
286			if (value <= subValue)
287			value = kEmptyHashValue;
288			else
289			value -= subValue;
290			items[i] = value;
291			}
292			}
293
294			static void MatchFinder_Normalize(CMatchFinder *p)
295			{
296			UInt32 subValue = MatchFinder_GetSubValue(p);
297			MatchFinder_Normalize3(subValue, p->hash, p->hashSizeSum + p->numSons);
298			MatchFinder_ReduceOffsets(p, subValue);
299			}
300
301			static void MatchFinder_CheckLimits(CMatchFinder *p)
302			{
303			if (p->pos == kMaxValForNormalize)
304			MatchFinder_Normalize(p);
305			if (!p->streamEndWasReached && p->keepSizeAfter == p->streamPos - p->pos)
306			MatchFinder_CheckAndMoveAndRead(p);
307			if (p->cyclicBufferPos == p->cyclicBufferSize)
308			p->cyclicBufferPos = 0;
309			MatchFinder_SetLimits(p);
310			}
311
312			static UInt32 * Hc_GetMatchesSpec(UInt32 lenLimit, UInt32 curMatch, UInt32 pos, const Byte cur, CLzRef son,
313			UInt32 _cyclicBufferPos, UInt32 _cyclicBufferSize, UInt32 cutValue,
314			UInt32 *distances, UInt32 maxLen)
315			{
316			son[_cyclicBufferPos] = curMatch;
317			for (;;)
318			{
319			UInt32 delta = pos - curMatch;
320			if (cutValue-- == 0 \|\| delta >= _cyclicBufferSize)
321			return distances;
322			{
323			const Byte *pb = cur - delta;
324			curMatch = son[_cyclicBufferPos - delta + ((delta > _cyclicBufferPos) ? _cyclicBufferSize : 0)];
325			if (pb[maxLen] == cur[maxLen] && pb == cur)
326			{
327			UInt32 len = 0;
328			while (++len != lenLimit)
329			if (pb[len] != cur[len])
330			break;
331			if (maxLen < len)
332			{
333			*distances++ = maxLen = len;
334			*distances++ = delta - 1;
335			if (len == lenLimit)
336			return distances;
337			}
338			}
339			}
340			}
341			}
342
343			UInt32 * GetMatchesSpec1(UInt32 lenLimit, UInt32 curMatch, UInt32 pos, const Byte cur, CLzRef son,
344			UInt32 _cyclicBufferPos, UInt32 _cyclicBufferSize, UInt32 cutValue,
345			UInt32 *distances, UInt32 maxLen)
346			{
347			CLzRef *ptr0 = son + (_cyclicBufferPos << 1) + 1;
348			CLzRef *ptr1 = son + (_cyclicBufferPos << 1);
349			UInt32 len0 = 0, len1 = 0;
350			for (;;)
351			{
352			UInt32 delta = pos - curMatch;
353			if (cutValue-- == 0 \|\| delta >= _cyclicBufferSize)
354			{
355			ptr0 = ptr1 = kEmptyHashValue;
356			return distances;
357			}
358			{
359			CLzRef *pair = son + ((_cyclicBufferPos - delta + ((delta > _cyclicBufferPos) ? _cyclicBufferSize : 0)) << 1);
360			const Byte *pb = cur - delta;
361			UInt32 len = (len0 < len1 ? len0 : len1);
362			if (pb[len] == cur[len])
363			{
364			if (++len != lenLimit && pb[len] == cur[len])
365			while (++len != lenLimit)
366			if (pb[len] != cur[len])
367			break;
368			if (maxLen < len)
369			{
370			*distances++ = maxLen = len;
371			*distances++ = delta - 1;
372			if (len == lenLimit)
373			{
374			*ptr1 = pair[0];
375			*ptr0 = pair[1];
376			return distances;
377			}
378			}
379			}
380			if (pb[len] < cur[len])
381			{
382			*ptr1 = curMatch;
383			ptr1 = pair + 1;
384			curMatch = *ptr1;
385			len1 = len;
386			}
387			else
388			{
389			*ptr0 = curMatch;
390			ptr0 = pair;
391			curMatch = *ptr0;
392			len0 = len;
393			}
394			}
395			}
396			}
397
398			static void SkipMatchesSpec(UInt32 lenLimit, UInt32 curMatch, UInt32 pos, const Byte cur, CLzRef son,
399			UInt32 _cyclicBufferPos, UInt32 _cyclicBufferSize, UInt32 cutValue)
400			{
401			CLzRef *ptr0 = son + (_cyclicBufferPos << 1) + 1;
402			CLzRef *ptr1 = son + (_cyclicBufferPos << 1);
403			UInt32 len0 = 0, len1 = 0;
404			for (;;)
405			{
406			UInt32 delta = pos - curMatch;
407			if (cutValue-- == 0 \|\| delta >= _cyclicBufferSize)
408			{
409			ptr0 = ptr1 = kEmptyHashValue;
410			return;
411			}
412			{
413			CLzRef *pair = son + ((_cyclicBufferPos - delta + ((delta > _cyclicBufferPos) ? _cyclicBufferSize : 0)) << 1);
414			const Byte *pb = cur - delta;
415			UInt32 len = (len0 < len1 ? len0 : len1);
416			if (pb[len] == cur[len])
417			{
418			while (++len != lenLimit)
419			if (pb[len] != cur[len])
420			break;
421			{
422			if (len == lenLimit)
423			{
424			*ptr1 = pair[0];
425			*ptr0 = pair[1];
426			return;
427			}
428			}
429			}
430			if (pb[len] < cur[len])
431			{
432			*ptr1 = curMatch;
433			ptr1 = pair + 1;
434			curMatch = *ptr1;
435			len1 = len;
436			}
437			else
438			{
439			*ptr0 = curMatch;
440			ptr0 = pair;
441			curMatch = *ptr0;
442			len0 = len;
443			}
444			}
445			}
446			}
447
448			#define MOVE_POS \
449			++p->cyclicBufferPos; \
450			p->buffer++; \
451			if (++p->pos == p->posLimit) MatchFinder_CheckLimits(p);
452
453			#define MOVE_POS_RET MOVE_POS return offset;
454
455			static void MatchFinder_MovePos(CMatchFinder *p) { MOVE_POS; }
456
457			#define GET_MATCHES_HEADER2(minLen, ret_op) \
458			UInt32 lenLimit; UInt32 hashValue; const Byte *cur; UInt32 curMatch; \
459			lenLimit = p->lenLimit; { if (lenLimit < minLen) { MatchFinder_MovePos(p); ret_op; }} \
460			cur = p->buffer;
461
462			#define GET_MATCHES_HEADER(minLen) GET_MATCHES_HEADER2(minLen, return 0)
463			#define SKIP_HEADER(minLen) GET_MATCHES_HEADER2(minLen, continue)
464
465			#define MF_PARAMS(p) p->pos, p->buffer, p->son, p->cyclicBufferPos, p->cyclicBufferSize, p->cutValue
466
467			#define GET_MATCHES_FOOTER(offset, maxLen) \
468			offset = (UInt32)(GetMatchesSpec1(lenLimit, curMatch, MF_PARAMS(p), \
469			distances + offset, maxLen) - distances); MOVE_POS_RET;
470
471			#define SKIP_FOOTER \
472			SkipMatchesSpec(lenLimit, curMatch, MF_PARAMS(p)); MOVE_POS;
473
474			static UInt32 Bt2_MatchFinder_GetMatches(CMatchFinder p, UInt32 distances)
475			{
476			UInt32 offset;
477			GET_MATCHES_HEADER(2)
478			HASH2_CALC;
479			curMatch = p->hash[hashValue];
480			p->hash[hashValue] = p->pos;
481			offset = 0;
482			GET_MATCHES_FOOTER(offset, 1)
483			}
484
485			UInt32 Bt3Zip_MatchFinder_GetMatches(CMatchFinder p, UInt32 distances)
486			{
487			UInt32 offset;
488			GET_MATCHES_HEADER(3)
489			HASH_ZIP_CALC;
490			curMatch = p->hash[hashValue];
491			p->hash[hashValue] = p->pos;
492			offset = 0;
493			GET_MATCHES_FOOTER(offset, 2)
494			}
495
496			static UInt32 Bt3_MatchFinder_GetMatches(CMatchFinder p, UInt32 distances)
497			{
498			UInt32 hash2Value, delta2, maxLen, offset;
499			GET_MATCHES_HEADER(3)
500
501			HASH3_CALC;
502
503			delta2 = p->pos - p->hash[hash2Value];
504			curMatch = p->hash[kFix3HashSize + hashValue];
505
506			p->hash[hash2Value] =
507			p->hash[kFix3HashSize + hashValue] = p->pos;
508
509
510			maxLen = 2;
511			offset = 0;
512			if (delta2 < p->cyclicBufferSize && (cur - delta2) == cur)
513			{
514			for (; maxLen != lenLimit; maxLen++)
515			if (cur[(ptrdiff_t)maxLen - delta2] != cur[maxLen])
516			break;
517			distances[0] = maxLen;
518			distances[1] = delta2 - 1;
519			offset = 2;
520			if (maxLen == lenLimit)
521			{
522			SkipMatchesSpec(lenLimit, curMatch, MF_PARAMS(p));
523			MOVE_POS_RET;
524			}
525			}
526			GET_MATCHES_FOOTER(offset, maxLen)
527			}
528
529			static UInt32 Bt4_MatchFinder_GetMatches(CMatchFinder p, UInt32 distances)
530			{
531			UInt32 hash2Value, hash3Value, delta2, delta3, maxLen, offset;
532			GET_MATCHES_HEADER(4)
533
534			HASH4_CALC;
535
536			delta2 = p->pos - p->hash[ hash2Value];
537			delta3 = p->pos - p->hash[kFix3HashSize + hash3Value];
538			curMatch = p->hash[kFix4HashSize + hashValue];
539
540			p->hash[ hash2Value] =
541			p->hash[kFix3HashSize + hash3Value] =
542			p->hash[kFix4HashSize + hashValue] = p->pos;
543
544			maxLen = 1;
545			offset = 0;
546			if (delta2 < p->cyclicBufferSize && (cur - delta2) == cur)
547			{
548			distances[0] = maxLen = 2;
549			distances[1] = delta2 - 1;
550			offset = 2;
551			}
552			if (delta2 != delta3 && delta3 < p->cyclicBufferSize && (cur - delta3) == cur)
553			{
554			maxLen = 3;
555			distances[offset + 1] = delta3 - 1;
556			offset += 2;
557			delta2 = delta3;
558			}
559			if (offset != 0)
560			{
561			for (; maxLen != lenLimit; maxLen++)
562			if (cur[(ptrdiff_t)maxLen - delta2] != cur[maxLen])
563			break;
564			distances[offset - 2] = maxLen;
565			if (maxLen == lenLimit)
566			{
567			SkipMatchesSpec(lenLimit, curMatch, MF_PARAMS(p));
568			MOVE_POS_RET;
569			}
570			}
571			if (maxLen < 3)
572			maxLen = 3;
573			GET_MATCHES_FOOTER(offset, maxLen)
574			}
575
576			static UInt32 Hc4_MatchFinder_GetMatches(CMatchFinder p, UInt32 distances)
577			{
578			UInt32 hash2Value, hash3Value, delta2, delta3, maxLen, offset;
579			GET_MATCHES_HEADER(4)
580
581			HASH4_CALC;
582
583			delta2 = p->pos - p->hash[ hash2Value];
584			delta3 = p->pos - p->hash[kFix3HashSize + hash3Value];
585			curMatch = p->hash[kFix4HashSize + hashValue];
586
587			p->hash[ hash2Value] =
588			p->hash[kFix3HashSize + hash3Value] =
589			p->hash[kFix4HashSize + hashValue] = p->pos;
590
591			maxLen = 1;
592			offset = 0;
593			if (delta2 < p->cyclicBufferSize && (cur - delta2) == cur)
594			{
595			distances[0] = maxLen = 2;
596			distances[1] = delta2 - 1;
597			offset = 2;
598			}
599			if (delta2 != delta3 && delta3 < p->cyclicBufferSize && (cur - delta3) == cur)
600			{
601			maxLen = 3;
602			distances[offset + 1] = delta3 - 1;
603			offset += 2;
604			delta2 = delta3;
605			}
606			if (offset != 0)
607			{
608			for (; maxLen != lenLimit; maxLen++)
609			if (cur[(ptrdiff_t)maxLen - delta2] != cur[maxLen])
610			break;
611			distances[offset - 2] = maxLen;
612			if (maxLen == lenLimit)
613			{
614			p->son[p->cyclicBufferPos] = curMatch;
615			MOVE_POS_RET;
616			}
617			}
618			if (maxLen < 3)
619			maxLen = 3;
620			offset = (UInt32)(Hc_GetMatchesSpec(lenLimit, curMatch, MF_PARAMS(p),
621			distances + offset, maxLen) - (distances));
622			MOVE_POS_RET
623			}
624
625			UInt32 Hc3Zip_MatchFinder_GetMatches(CMatchFinder p, UInt32 distances)
626			{
627			UInt32 offset;
628			GET_MATCHES_HEADER(3)
629			HASH_ZIP_CALC;
630			curMatch = p->hash[hashValue];
631			p->hash[hashValue] = p->pos;
632			offset = (UInt32)(Hc_GetMatchesSpec(lenLimit, curMatch, MF_PARAMS(p),
633			distances, 2) - (distances));
634			MOVE_POS_RET
635			}
636
637			static void Bt2_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
638			{
639			do
640			{
641			SKIP_HEADER(2)
642			HASH2_CALC;
643			curMatch = p->hash[hashValue];
644			p->hash[hashValue] = p->pos;
645			SKIP_FOOTER
646			}
647			while (--num != 0);
648			}
649
650			void Bt3Zip_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
651			{
652			do
653			{
654			SKIP_HEADER(3)
655			HASH_ZIP_CALC;
656			curMatch = p->hash[hashValue];
657			p->hash[hashValue] = p->pos;
658			SKIP_FOOTER
659			}
660			while (--num != 0);
661			}
662
663			static void Bt3_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
664			{
665			do
666			{
667			UInt32 hash2Value;
668			SKIP_HEADER(3)
669			HASH3_CALC;
670			curMatch = p->hash[kFix3HashSize + hashValue];
671			p->hash[hash2Value] =
672			p->hash[kFix3HashSize + hashValue] = p->pos;
673			SKIP_FOOTER
674			}
675			while (--num != 0);
676			}
677
678			static void Bt4_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
679			{
680			do
681			{
682			UInt32 hash2Value, hash3Value;
683			SKIP_HEADER(4)
684			HASH4_CALC;
685			curMatch = p->hash[kFix4HashSize + hashValue];
686			p->hash[ hash2Value] =
687			p->hash[kFix3HashSize + hash3Value] = p->pos;
688			p->hash[kFix4HashSize + hashValue] = p->pos;
689			SKIP_FOOTER
690			}
691			while (--num != 0);
692			}
693
694			static void Hc4_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
695			{
696			do
697			{
698			UInt32 hash2Value, hash3Value;
699			SKIP_HEADER(4)
700			HASH4_CALC;
701			curMatch = p->hash[kFix4HashSize + hashValue];
702			p->hash[ hash2Value] =
703			p->hash[kFix3HashSize + hash3Value] =
704			p->hash[kFix4HashSize + hashValue] = p->pos;
705			p->son[p->cyclicBufferPos] = curMatch;
706			MOVE_POS
707			}
708			while (--num != 0);
709			}
710
711			void Hc3Zip_MatchFinder_Skip(CMatchFinder *p, UInt32 num)
712			{
713			do
714			{
715			SKIP_HEADER(3)
716			HASH_ZIP_CALC;
717			curMatch = p->hash[hashValue];
718			p->hash[hashValue] = p->pos;
719			p->son[p->cyclicBufferPos] = curMatch;
720			MOVE_POS
721			}
722			while (--num != 0);
723			}
724
725			void MatchFinder_CreateVTable(CMatchFinder p, IMatchFinder vTable)
726			{
727			vTable->Init = (Mf_Init_Func)MatchFinder_Init;
728			vTable->GetIndexByte = (Mf_GetIndexByte_Func)MatchFinder_GetIndexByte;
729			vTable->GetNumAvailableBytes = (Mf_GetNumAvailableBytes_Func)MatchFinder_GetNumAvailableBytes;
730			vTable->GetPointerToCurrentPos = (Mf_GetPointerToCurrentPos_Func)MatchFinder_GetPointerToCurrentPos;
731			if (!p->btMode)
732			{
733			vTable->GetMatches = (Mf_GetMatches_Func)Hc4_MatchFinder_GetMatches;
734			vTable->Skip = (Mf_Skip_Func)Hc4_MatchFinder_Skip;
735			}
736			else if (p->numHashBytes == 2)
737			{
738			vTable->GetMatches = (Mf_GetMatches_Func)Bt2_MatchFinder_GetMatches;
739			vTable->Skip = (Mf_Skip_Func)Bt2_MatchFinder_Skip;
740			}
741			else if (p->numHashBytes == 3)
742			{
743			vTable->GetMatches = (Mf_GetMatches_Func)Bt3_MatchFinder_GetMatches;
744			vTable->Skip = (Mf_Skip_Func)Bt3_MatchFinder_Skip;
745			}
746			else
747			{
748			vTable->GetMatches = (Mf_GetMatches_Func)Bt4_MatchFinder_GetMatches;
749			vTable->Skip = (Mf_Skip_Func)Bt4_MatchFinder_Skip;
750			}
751			}