368 lines
9.1 KiB
C#
368 lines
9.1 KiB
C#
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// LzBinTree.cs
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using System;
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namespace SevenZip.Compression.LZ
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{
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public class BinTree : InWindow, IMatchFinder
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{
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UInt32 _cyclicBufferPos;
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UInt32 _cyclicBufferSize = 0;
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UInt32 _matchMaxLen;
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UInt32[] _son;
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UInt32[] _hash;
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UInt32 _cutValue = 0xFF;
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UInt32 _hashMask;
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UInt32 _hashSizeSum = 0;
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bool HASH_ARRAY = true;
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const UInt32 kHash2Size = 1 << 10;
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const UInt32 kHash3Size = 1 << 16;
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const UInt32 kBT2HashSize = 1 << 16;
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const UInt32 kStartMaxLen = 1;
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const UInt32 kHash3Offset = kHash2Size;
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const UInt32 kEmptyHashValue = 0;
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const UInt32 kMaxValForNormalize = ((UInt32)1 << 31) - 1;
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UInt32 kNumHashDirectBytes = 0;
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UInt32 kMinMatchCheck = 4;
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UInt32 kFixHashSize = kHash2Size + kHash3Size;
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public void SetType(int numHashBytes)
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{
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HASH_ARRAY = (numHashBytes > 2);
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if (HASH_ARRAY)
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{
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kNumHashDirectBytes = 0;
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kMinMatchCheck = 4;
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kFixHashSize = kHash2Size + kHash3Size;
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}
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else
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{
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kNumHashDirectBytes = 2;
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kMinMatchCheck = 2 + 1;
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kFixHashSize = 0;
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}
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}
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public new void SetStream(System.IO.Stream stream) { base.SetStream(stream); }
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public new void ReleaseStream() { base.ReleaseStream(); }
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public new void Init()
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{
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base.Init();
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for (UInt32 i = 0; i < _hashSizeSum; i++)
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_hash[i] = kEmptyHashValue;
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_cyclicBufferPos = 0;
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ReduceOffsets(-1);
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}
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public new void MovePos()
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{
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if (++_cyclicBufferPos >= _cyclicBufferSize)
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_cyclicBufferPos = 0;
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base.MovePos();
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if (_pos == kMaxValForNormalize)
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Normalize();
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}
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public new Byte GetIndexByte(Int32 index) { return base.GetIndexByte(index); }
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public new UInt32 GetMatchLen(Int32 index, UInt32 distance, UInt32 limit)
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{ return base.GetMatchLen(index, distance, limit); }
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public new UInt32 GetNumAvailableBytes() { return base.GetNumAvailableBytes(); }
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public void Create(UInt32 historySize, UInt32 keepAddBufferBefore,
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UInt32 matchMaxLen, UInt32 keepAddBufferAfter)
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{
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if (historySize > kMaxValForNormalize - 256)
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throw new Exception();
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_cutValue = 16 + (matchMaxLen >> 1);
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UInt32 windowReservSize = (historySize + keepAddBufferBefore +
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matchMaxLen + keepAddBufferAfter) / 2 + 256;
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base.Create(historySize + keepAddBufferBefore, matchMaxLen + keepAddBufferAfter, windowReservSize);
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_matchMaxLen = matchMaxLen;
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UInt32 cyclicBufferSize = historySize + 1;
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if (_cyclicBufferSize != cyclicBufferSize)
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_son = new UInt32[(_cyclicBufferSize = cyclicBufferSize) * 2];
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UInt32 hs = kBT2HashSize;
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if (HASH_ARRAY)
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{
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hs = historySize - 1;
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hs |= (hs >> 1);
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hs |= (hs >> 2);
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hs |= (hs >> 4);
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hs |= (hs >> 8);
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hs >>= 1;
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hs |= 0xFFFF;
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if (hs > (1 << 24))
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hs >>= 1;
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_hashMask = hs;
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hs++;
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hs += kFixHashSize;
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}
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if (hs != _hashSizeSum)
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_hash = new UInt32[_hashSizeSum = hs];
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}
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public UInt32 GetMatches(UInt32[] distances)
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{
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UInt32 lenLimit;
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if (_pos + _matchMaxLen <= _streamPos)
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lenLimit = _matchMaxLen;
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else
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{
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lenLimit = _streamPos - _pos;
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if (lenLimit < kMinMatchCheck)
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{
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MovePos();
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return 0;
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}
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}
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UInt32 offset = 0;
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UInt32 matchMinPos = (_pos > _cyclicBufferSize) ? (_pos - _cyclicBufferSize) : 0;
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UInt32 cur = _bufferOffset + _pos;
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UInt32 maxLen = kStartMaxLen; // to avoid items for len < hashSize;
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UInt32 hashValue, hash2Value = 0, hash3Value = 0;
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if (HASH_ARRAY)
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{
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UInt32 temp = CRC.Table[_bufferBase[cur]] ^ _bufferBase[cur + 1];
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hash2Value = temp & (kHash2Size - 1);
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temp ^= ((UInt32)(_bufferBase[cur + 2]) << 8);
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hash3Value = temp & (kHash3Size - 1);
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hashValue = (temp ^ (CRC.Table[_bufferBase[cur + 3]] << 5)) & _hashMask;
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}
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else
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hashValue = _bufferBase[cur] ^ ((UInt32)(_bufferBase[cur + 1]) << 8);
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UInt32 curMatch = _hash[kFixHashSize + hashValue];
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if (HASH_ARRAY)
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{
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UInt32 curMatch2 = _hash[hash2Value];
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UInt32 curMatch3 = _hash[kHash3Offset + hash3Value];
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_hash[hash2Value] = _pos;
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_hash[kHash3Offset + hash3Value] = _pos;
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if (curMatch2 > matchMinPos)
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if (_bufferBase[_bufferOffset + curMatch2] == _bufferBase[cur])
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{
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distances[offset++] = maxLen = 2;
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distances[offset++] = _pos - curMatch2 - 1;
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}
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if (curMatch3 > matchMinPos)
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if (_bufferBase[_bufferOffset + curMatch3] == _bufferBase[cur])
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{
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if (curMatch3 == curMatch2)
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offset -= 2;
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distances[offset++] = maxLen = 3;
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distances[offset++] = _pos - curMatch3 - 1;
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curMatch2 = curMatch3;
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}
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if (offset != 0 && curMatch2 == curMatch)
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{
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offset -= 2;
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maxLen = kStartMaxLen;
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}
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}
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_hash[kFixHashSize + hashValue] = _pos;
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UInt32 ptr0 = (_cyclicBufferPos << 1) + 1;
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UInt32 ptr1 = (_cyclicBufferPos << 1);
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UInt32 len0, len1;
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len0 = len1 = kNumHashDirectBytes;
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if (kNumHashDirectBytes != 0)
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{
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if (curMatch > matchMinPos)
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{
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if (_bufferBase[_bufferOffset + curMatch + kNumHashDirectBytes] !=
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_bufferBase[cur + kNumHashDirectBytes])
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{
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distances[offset++] = maxLen = kNumHashDirectBytes;
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distances[offset++] = _pos - curMatch - 1;
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}
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}
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}
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UInt32 count = _cutValue;
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while(true)
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{
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if(curMatch <= matchMinPos || count-- == 0)
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{
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_son[ptr0] = _son[ptr1] = kEmptyHashValue;
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break;
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}
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UInt32 delta = _pos - curMatch;
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UInt32 cyclicPos = ((delta <= _cyclicBufferPos) ?
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(_cyclicBufferPos - delta) :
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(_cyclicBufferPos - delta + _cyclicBufferSize)) << 1;
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UInt32 pby1 = _bufferOffset + curMatch;
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UInt32 len = Math.Min(len0, len1);
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if (_bufferBase[pby1 + len] == _bufferBase[cur + len])
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{
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while(++len != lenLimit)
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if (_bufferBase[pby1 + len] != _bufferBase[cur + len])
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break;
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if (maxLen < len)
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{
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distances[offset++] = maxLen = len;
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distances[offset++] = delta - 1;
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if (len == lenLimit)
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{
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_son[ptr1] = _son[cyclicPos];
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_son[ptr0] = _son[cyclicPos + 1];
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break;
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}
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}
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}
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if (_bufferBase[pby1 + len] < _bufferBase[cur + len])
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{
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_son[ptr1] = curMatch;
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ptr1 = cyclicPos + 1;
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curMatch = _son[ptr1];
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len1 = len;
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}
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else
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{
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_son[ptr0] = curMatch;
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ptr0 = cyclicPos;
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curMatch = _son[ptr0];
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len0 = len;
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}
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}
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MovePos();
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return offset;
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}
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public void Skip(UInt32 num)
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{
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do
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{
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UInt32 lenLimit;
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if (_pos + _matchMaxLen <= _streamPos)
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lenLimit = _matchMaxLen;
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else
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{
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lenLimit = _streamPos - _pos;
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if (lenLimit < kMinMatchCheck)
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{
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MovePos();
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continue;
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}
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}
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UInt32 matchMinPos = (_pos > _cyclicBufferSize) ? (_pos - _cyclicBufferSize) : 0;
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UInt32 cur = _bufferOffset + _pos;
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UInt32 hashValue;
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if (HASH_ARRAY)
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{
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UInt32 temp = CRC.Table[_bufferBase[cur]] ^ _bufferBase[cur + 1];
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UInt32 hash2Value = temp & (kHash2Size - 1);
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_hash[hash2Value] = _pos;
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temp ^= ((UInt32)(_bufferBase[cur + 2]) << 8);
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UInt32 hash3Value = temp & (kHash3Size - 1);
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_hash[kHash3Offset + hash3Value] = _pos;
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hashValue = (temp ^ (CRC.Table[_bufferBase[cur + 3]] << 5)) & _hashMask;
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}
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else
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hashValue = _bufferBase[cur] ^ ((UInt32)(_bufferBase[cur + 1]) << 8);
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UInt32 curMatch = _hash[kFixHashSize + hashValue];
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_hash[kFixHashSize + hashValue] = _pos;
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UInt32 ptr0 = (_cyclicBufferPos << 1) + 1;
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UInt32 ptr1 = (_cyclicBufferPos << 1);
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UInt32 len0, len1;
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len0 = len1 = kNumHashDirectBytes;
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UInt32 count = _cutValue;
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while (true)
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{
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if (curMatch <= matchMinPos || count-- == 0)
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{
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_son[ptr0] = _son[ptr1] = kEmptyHashValue;
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break;
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}
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UInt32 delta = _pos - curMatch;
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UInt32 cyclicPos = ((delta <= _cyclicBufferPos) ?
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(_cyclicBufferPos - delta) :
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(_cyclicBufferPos - delta + _cyclicBufferSize)) << 1;
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UInt32 pby1 = _bufferOffset + curMatch;
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UInt32 len = Math.Min(len0, len1);
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if (_bufferBase[pby1 + len] == _bufferBase[cur + len])
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{
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while (++len != lenLimit)
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if (_bufferBase[pby1 + len] != _bufferBase[cur + len])
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break;
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if (len == lenLimit)
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{
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_son[ptr1] = _son[cyclicPos];
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_son[ptr0] = _son[cyclicPos + 1];
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break;
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}
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}
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if (_bufferBase[pby1 + len] < _bufferBase[cur + len])
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{
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_son[ptr1] = curMatch;
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ptr1 = cyclicPos + 1;
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curMatch = _son[ptr1];
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len1 = len;
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}
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else
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{
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_son[ptr0] = curMatch;
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ptr0 = cyclicPos;
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curMatch = _son[ptr0];
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len0 = len;
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}
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}
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MovePos();
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}
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while (--num != 0);
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}
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void NormalizeLinks(UInt32[] items, UInt32 numItems, UInt32 subValue)
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{
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for (UInt32 i = 0; i < numItems; i++)
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{
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UInt32 value = items[i];
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if (value <= subValue)
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value = kEmptyHashValue;
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else
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value -= subValue;
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items[i] = value;
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}
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}
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void Normalize()
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{
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UInt32 subValue = _pos - _cyclicBufferSize;
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NormalizeLinks(_son, _cyclicBufferSize * 2, subValue);
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NormalizeLinks(_hash, _hashSizeSum, subValue);
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ReduceOffsets((Int32)subValue);
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}
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public void SetCutValue(UInt32 cutValue) { _cutValue = cutValue; }
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}
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}
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