/*
* Copyright (c) 2009 Julien Ponge. All rights reserved.
*
* <julien.ponge@gmail.com>
* http://julien.ponge.info/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This work is based on the LZMA SDK by Igor Pavlov.
* The LZMA SDK is placed under the public domain, and can be obtained from
*
* http://www.7-zip.org/sdk.html
*
* The LzmaInputStream and LzmaOutputStream classes were inspired by the
* work of Christopher League, although they are not derivative works.
*
* http://contrapunctus.net/league/haques/lzmajio/
*/
package lzma.sdk.lz;
import java.io.IOException;
import java.util.Arrays;
public class BinTree extends InWindow
{
int _cyclicBufferPos;
int _cyclicBufferSize = 0;
int _matchMaxLen;
int[] _son;
int[] _hash;
int _cutValue = 0xFF;
int _hashMask;
int _hashSizeSum = 0;
private final boolean HASH_ARRAY;
static final int kHash2Size = 1 << 10;
static final int kHash3Size = 1 << 16;
static final int kBT2HashSize = 1 << 16;
static final int kStartMaxLen = 1;
static final int kHash3Offset = kHash2Size;
static final int kEmptyHashValue = 0;
static final int kMaxValForNormalize = (1 << 30) - 1;
int kNumHashDirectBytes = 0;
int kMinMatchCheck = 4;
int kFixHashSize = kHash2Size + kHash3Size;
public BinTree(int numHashBytes)
{
HASH_ARRAY = (numHashBytes > 2);
if (HASH_ARRAY) {
kNumHashDirectBytes = 0;
kMinMatchCheck = 4;
kFixHashSize = kHash2Size + kHash3Size;
} else {
kNumHashDirectBytes = 2;
kMinMatchCheck = 2 + 1;
kFixHashSize = 0;
}
}
public void init() throws IOException
{
super.init();
Arrays.fill(_hash, 0, _hashSizeSum, kEmptyHashValue);
_cyclicBufferPos = 0;
reduceOffsets(-1);
}
public void movePos() throws IOException
{
if (++_cyclicBufferPos >= _cyclicBufferSize)
{
_cyclicBufferPos = 0;
}
super.movePos();
if (_pos == kMaxValForNormalize)
{
normalize();
}
}
public boolean create(int historySize, int keepAddBufferBefore,
int matchMaxLen, int keepAddBufferAfter)
{
if (historySize > kMaxValForNormalize - 256)
{
return false;
}
_cutValue = 16 + (matchMaxLen >> 1);
int windowReservSize = (historySize + keepAddBufferBefore +
matchMaxLen + keepAddBufferAfter) / 2 + 256;
super.create(historySize + keepAddBufferBefore, matchMaxLen + keepAddBufferAfter, windowReservSize);
_matchMaxLen = matchMaxLen;
int cyclicBufferSize = historySize + 1;
if (_cyclicBufferSize != cyclicBufferSize)
{
_son = new int[(_cyclicBufferSize = cyclicBufferSize) * 2];
}
int hs = kBT2HashSize;
if (HASH_ARRAY)
{
hs = historySize - 1;
hs |= (hs >> 1);
hs |= (hs >> 2);
hs |= (hs >> 4);
hs |= (hs >> 8);
hs >>= 1;
hs |= 0xFFFF;
if (hs > (1 << 24))
{
hs >>= 1;
}
_hashMask = hs;
hs++;
hs += kFixHashSize;
}
if (hs != _hashSizeSum)
{
_hash = new int[_hashSizeSum = hs];
}
return true;
}
public int getMatches(int[] distances) throws IOException
{
int lenLimit;
if (_pos + _matchMaxLen <= _streamPos)
{
lenLimit = _matchMaxLen;
}
else
{
lenLimit = _streamPos - _pos;
if (lenLimit < kMinMatchCheck)
{
movePos();
return 0;
}
}
int offset = 0;
int matchMinPos = (_pos > _cyclicBufferSize) ? (_pos - _cyclicBufferSize) : 0;
int cur = _bufferOffset + _pos;
int maxLen = kStartMaxLen; // to avoid items for len < hashSize;
int hashValue, hash2Value = 0, hash3Value = 0;
if (HASH_ARRAY)
{
int temp = CrcTable[_bufferBase[cur] & 0xFF] ^ (_bufferBase[cur + 1] & 0xFF);
hash2Value = temp & (kHash2Size - 1);
temp ^= ((_bufferBase[cur + 2] & 0xFF) << 8);
hash3Value = temp & (kHash3Size - 1);
hashValue = (temp ^ (CrcTable[_bufferBase[cur + 3] & 0xFF] << 5)) & _hashMask;
}
else
{
hashValue = ((_bufferBase[cur] & 0xFF) ^ ((_bufferBase[cur + 1] & 0xFF) << 8));
}
int curMatch = _hash[kFixHashSize + hashValue];
if (HASH_ARRAY)
{
int curMatch2 = _hash[hash2Value];
int curMatch3 = _hash[kHash3Offset + hash3Value];
_hash[hash2Value] = _pos;
_hash[kHash3Offset + hash3Value] = _pos;
if (curMatch2 > matchMinPos)
{
if (_bufferBase[_bufferOffset + curMatch2] == _bufferBase[cur])
{
distances[offset++] = maxLen = 2;
distances[offset++] = _pos - curMatch2 - 1;
}
}
if (curMatch3 > matchMinPos)
{
if (_bufferBase[_bufferOffset + curMatch3] == _bufferBase[cur])
{
if (curMatch3 == curMatch2)
{
offset -= 2;
}
distances[offset++] = maxLen = 3;
distances[offset++] = _pos - curMatch3 - 1;
curMatch2 = curMatch3;
}
}
if (offset != 0 && curMatch2 == curMatch)
{
offset -= 2;
maxLen = kStartMaxLen;
}
}
_hash[kFixHashSize + hashValue] = _pos;
int ptr0 = (_cyclicBufferPos << 1) + 1;
int ptr1 = (_cyclicBufferPos << 1);
int len0, len1;
len0 = len1 = kNumHashDirectBytes;
if (kNumHashDirectBytes != 0)
{
if (curMatch > matchMinPos)
{
if (_bufferBase[_bufferOffset + curMatch + kNumHashDirectBytes] !=
_bufferBase[cur + kNumHashDirectBytes])
{
distances[offset++] = maxLen = kNumHashDirectBytes;
distances[offset++] = _pos - curMatch - 1;
}
}
}
int count = _cutValue;
while (true)
{
if (curMatch <= matchMinPos || count-- == 0)
{
_son[ptr0] = _son[ptr1] = kEmptyHashValue;
break;
}
int delta = _pos - curMatch;
int cyclicPos = ((delta <= _cyclicBufferPos) ?
(_cyclicBufferPos - delta) :
(_cyclicBufferPos - delta + _cyclicBufferSize)) << 1;
int pby1 = _bufferOffset + curMatch;
int len = Math.min(len0, len1);
if (_bufferBase[pby1 + len] == _bufferBase[cur + len])
{
while (++len != lenLimit)
{
if (_bufferBase[pby1 + len] != _bufferBase[cur + len])
{
break;
}
}
if (maxLen < len)
{
distances[offset++] = maxLen = len;
distances[offset++] = delta - 1;
if (len == lenLimit)
{
_son[ptr1] = _son[cyclicPos];
_son[ptr0] = _son[cyclicPos + 1];
break;
}
}
}
if ((_bufferBase[pby1 + len] & 0xFF) < (_bufferBase[cur + len] & 0xFF))
{
_son[ptr1] = curMatch;
ptr1 = cyclicPos + 1;
curMatch = _son[ptr1];
len1 = len;
}
else
{
_son[ptr0] = curMatch;
ptr0 = cyclicPos;
curMatch = _son[ptr0];
len0 = len;
}
}
movePos();
return offset;
}
public void skip(int num) throws IOException
{
do
{
int lenLimit;
if (_pos + _matchMaxLen <= _streamPos)
{
lenLimit = _matchMaxLen;
}
else
{
lenLimit = _streamPos - _pos;
if (lenLimit < kMinMatchCheck)
{
movePos();
continue;
}
}
int matchMinPos = (_pos > _cyclicBufferSize) ? (_pos - _cyclicBufferSize) : 0;
int cur = _bufferOffset + _pos;
int hashValue;
if (HASH_ARRAY)
{
int temp = CrcTable[_bufferBase[cur] & 0xFF] ^ (_bufferBase[cur + 1] & 0xFF);
int hash2Value = temp & (kHash2Size - 1);
_hash[hash2Value] = _pos;
temp ^= ((_bufferBase[cur + 2] & 0xFF) << 8);
int hash3Value = temp & (kHash3Size - 1);
_hash[kHash3Offset + hash3Value] = _pos;
hashValue = (temp ^ (CrcTable[_bufferBase[cur + 3] & 0xFF] << 5)) & _hashMask;
}
else
{
hashValue = ((_bufferBase[cur] & 0xFF) ^ ((_bufferBase[cur + 1] & 0xFF) << 8));
}
int curMatch = _hash[kFixHashSize + hashValue];
_hash[kFixHashSize + hashValue] = _pos;
int ptr0 = (_cyclicBufferPos << 1) + 1;
int ptr1 = (_cyclicBufferPos << 1);
int len0, len1;
len0 = len1 = kNumHashDirectBytes;
int count = _cutValue;
while (true)
{
if (curMatch <= matchMinPos || count-- == 0)
{
_son[ptr0] = _son[ptr1] = kEmptyHashValue;
break;
}
int delta = _pos - curMatch;
int cyclicPos = ((delta <= _cyclicBufferPos) ?
(_cyclicBufferPos - delta) :
(_cyclicBufferPos - delta + _cyclicBufferSize)) << 1;
int pby1 = _bufferOffset + curMatch;
int len = Math.min(len0, len1);
if (_bufferBase[pby1 + len] == _bufferBase[cur + len])
{
while (++len != lenLimit)
{
if (_bufferBase[pby1 + len] != _bufferBase[cur + len])
{
break;
}
}
if (len == lenLimit)
{
_son[ptr1] = _son[cyclicPos];
_son[ptr0] = _son[cyclicPos + 1];
break;
}
}
if ((_bufferBase[pby1 + len] & 0xFF) < (_bufferBase[cur + len] & 0xFF))
{
_son[ptr1] = curMatch;
ptr1 = cyclicPos + 1;
curMatch = _son[ptr1];
len1 = len;
}
else
{
_son[ptr0] = curMatch;
ptr0 = cyclicPos;
curMatch = _son[ptr0];
len0 = len;
}
}
movePos();
}
while (--num != 0);
}
void normalizeLinks(int[] items, int numItems, int subValue)
{
for (int i = 0; i < numItems; i++)
{
int value = items[i];
if (value <= subValue)
{
value = kEmptyHashValue;
}
else
{
value -= subValue;
}
items[i] = value;
}
}
void normalize()
{
int subValue = _pos - _cyclicBufferSize;
normalizeLinks(_son, _cyclicBufferSize * 2, subValue);
normalizeLinks(_hash, _hashSizeSum, subValue);
reduceOffsets(subValue);
}
private static final int[] CrcTable = new int[256];
static
{
for (int i = 0; i < 256; i++)
{
int r = i;
for (int j = 0; j < 8; j++)
{
if ((r & 1) != 0)
{
r = (r >>> 1) ^ 0xEDB88320;
}
else
{
r >>>= 1;
}
}
CrcTable[i] = r;
}
}
}