com.badlogic.gdx.utils.compression.lz.BinTree Maven / Gradle / Ivy
// LZ.BinTree
package com.badlogic.gdx.utils.compression.lz;
import java.io.IOException;
public class BinTree extends InWindow {
int _cyclicBufferPos;
int _cyclicBufferSize = 0;
int _matchMaxLen;
int[] _son;
int[] _hash;
int _cutValue = 0xFF;
int _hashMask;
int _hashSizeSum = 0;
boolean HASH_ARRAY = true;
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 void SetType (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();
for (int i = 0; i < _hashSizeSum; i++)
_hash[i] = 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 ^= ((int)(_bufferBase[cur + 2] & 0xFF) << 8);
hash3Value = temp & (kHash3Size - 1);
hashValue = (temp ^ (CrcTable[_bufferBase[cur + 3] & 0xFF] << 5)) & _hashMask;
} else
hashValue = ((_bufferBase[cur] & 0xFF) ^ ((int)(_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 ^= ((int)(_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) ^ ((int)(_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);
}
public void SetCutValue (int cutValue) {
_cutValue = cutValue;
}
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;
}
}
}