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| (Empty) |
| 1 // LzInWindow.cs | |
| 2 | |
| 3 using System; | |
| 4 | |
| 5 namespace SevenZip.Compression.LZ | |
| 6 { | |
| 7 public class InWindow | |
| 8 { | |
| 9 public Byte[] _bufferBase = null; // pointer to buffer with data | |
| 10 System.IO.Stream _stream; | |
| 11 UInt32 _posLimit; // offset (from _buffer) of first byte when ne
w block reading must be done | |
| 12 bool _streamEndWasReached; // if (true) then _streamPos shows re
al end of stream | |
| 13 | |
| 14 UInt32 _pointerToLastSafePosition; | |
| 15 | |
| 16 public UInt32 _bufferOffset; | |
| 17 | |
| 18 public UInt32 _blockSize; // Size of Allocated memory block | |
| 19 public UInt32 _pos; // offset (from _buffer) of curent byte | |
| 20 UInt32 _keepSizeBefore; // how many BYTEs must be kept in buffer
before _pos | |
| 21 UInt32 _keepSizeAfter; // how many BYTEs must be kept buffer aft
er _pos | |
| 22 public UInt32 _streamPos; // offset (from _buffer) of first not
read byte from Stream | |
| 23 | |
| 24 public void MoveBlock() | |
| 25 { | |
| 26 UInt32 offset = (UInt32)(_bufferOffset) + _pos - _keepSi
zeBefore; | |
| 27 // we need one additional byte, since MovePos moves on 1
byte. | |
| 28 if (offset > 0) | |
| 29 offset--; | |
| 30 | |
| 31 UInt32 numBytes = (UInt32)(_bufferOffset) + _streamPos -
offset; | |
| 32 | |
| 33 // check negative offset ???? | |
| 34 for (UInt32 i = 0; i < numBytes; i++) | |
| 35 _bufferBase[i] = _bufferBase[offset + i]; | |
| 36 _bufferOffset -= offset; | |
| 37 } | |
| 38 | |
| 39 public virtual void ReadBlock() | |
| 40 { | |
| 41 if (_streamEndWasReached) | |
| 42 return; | |
| 43 while (true) | |
| 44 { | |
| 45 int size = (int)((0 - _bufferOffset) + _blockSiz
e - _streamPos); | |
| 46 if (size == 0) | |
| 47 return; | |
| 48 int numReadBytes = _stream.Read(_bufferBase, (in
t)(_bufferOffset + _streamPos), size); | |
| 49 if (numReadBytes == 0) | |
| 50 { | |
| 51 _posLimit = _streamPos; | |
| 52 UInt32 pointerToPostion = _bufferOffset
+ _posLimit; | |
| 53 if (pointerToPostion > _pointerToLastSaf
ePosition) | |
| 54 _posLimit = (UInt32)(_pointerToL
astSafePosition - _bufferOffset); | |
| 55 | |
| 56 _streamEndWasReached = true; | |
| 57 return; | |
| 58 } | |
| 59 _streamPos += (UInt32)numReadBytes; | |
| 60 if (_streamPos >= _pos + _keepSizeAfter) | |
| 61 _posLimit = _streamPos - _keepSizeAfter; | |
| 62 } | |
| 63 } | |
| 64 | |
| 65 void Free() { _bufferBase = null; } | |
| 66 | |
| 67 public void Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter,
UInt32 keepSizeReserv) | |
| 68 { | |
| 69 _keepSizeBefore = keepSizeBefore; | |
| 70 _keepSizeAfter = keepSizeAfter; | |
| 71 UInt32 blockSize = keepSizeBefore + keepSizeAfter + keep
SizeReserv; | |
| 72 if (_bufferBase == null || _blockSize != blockSize) | |
| 73 { | |
| 74 Free(); | |
| 75 _blockSize = blockSize; | |
| 76 _bufferBase = new Byte[_blockSize]; | |
| 77 } | |
| 78 _pointerToLastSafePosition = _blockSize - keepSizeAfter; | |
| 79 } | |
| 80 | |
| 81 public void SetStream(System.IO.Stream stream) { _stream = strea
m; } | |
| 82 public void ReleaseStream() { _stream = null; } | |
| 83 | |
| 84 public void Init() | |
| 85 { | |
| 86 _bufferOffset = 0; | |
| 87 _pos = 0; | |
| 88 _streamPos = 0; | |
| 89 _streamEndWasReached = false; | |
| 90 ReadBlock(); | |
| 91 } | |
| 92 | |
| 93 public void MovePos() | |
| 94 { | |
| 95 _pos++; | |
| 96 if (_pos > _posLimit) | |
| 97 { | |
| 98 UInt32 pointerToPostion = _bufferOffset + _pos; | |
| 99 if (pointerToPostion > _pointerToLastSafePositio
n) | |
| 100 MoveBlock(); | |
| 101 ReadBlock(); | |
| 102 } | |
| 103 } | |
| 104 | |
| 105 public Byte GetIndexByte(Int32 index) { return _bufferBase[_buff
erOffset + _pos + index]; } | |
| 106 | |
| 107 // index + limit have not to exceed _keepSizeAfter; | |
| 108 public UInt32 GetMatchLen(Int32 index, UInt32 distance, UInt32 l
imit) | |
| 109 { | |
| 110 if (_streamEndWasReached) | |
| 111 if ((_pos + index) + limit > _streamPos) | |
| 112 limit = _streamPos - (UInt32)(_pos + ind
ex); | |
| 113 distance++; | |
| 114 // Byte *pby = _buffer + (size_t)_pos + index; | |
| 115 UInt32 pby = _bufferOffset + _pos + (UInt32)index; | |
| 116 | |
| 117 UInt32 i; | |
| 118 for (i = 0; i < limit && _bufferBase[pby + i] == _buffer
Base[pby + i - distance]; i++); | |
| 119 return i; | |
| 120 } | |
| 121 | |
| 122 public UInt32 GetNumAvailableBytes() { return _streamPos - _pos;
} | |
| 123 | |
| 124 public void ReduceOffsets(Int32 subValue) | |
| 125 { | |
| 126 _bufferOffset += (UInt32)subValue; | |
| 127 _posLimit -= (UInt32)subValue; | |
| 128 _pos -= (UInt32)subValue; | |
| 129 _streamPos -= (UInt32)subValue; | |
| 130 } | |
| 131 } | |
| 132 } | |
| OLD | NEW |
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Chromium Code Reviews
Issue 624713003:
Keep only base/extractor.[cc|h]. (Closed)
Base URL: https://chromium.googlesource.com/external/omaha.git@master