Initial commit - WPinternals 2.6

DiscUtils/Compression/BZip2RleStream.cs

@@ -0,0 +1,161 @@
+//
+// Copyright (c) 2008-2011, Kenneth Bell
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+
+//
+// Based on "libbzip2", Copyright (C) 1996-2007 Julian R Seward.
+//
+
+namespace DiscUtils.Compression
+{
+    using System;
+    using System.IO;
+
+    internal class BZip2RleStream : Stream
+    {
+        private long _position;
+        private byte[] _blockBuffer;
+        private int _blockOffset;
+        private int _blockRemaining;
+
+        private int _numSame;
+        private byte _lastByte;
+        private int _runBytesOutstanding;
+
+        public BZip2RleStream()
+        {
+        }
+
+        public bool AtEof
+        {
+            get { return _runBytesOutstanding == 0 && _blockRemaining == 0; }
+        }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return false; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return false; }
+        }
+
+        public override long Length
+        {
+            get { throw new NotSupportedException(); }
+        }
+
+        public override long Position
+        {
+            get { return _position; }
+            set { throw new NotSupportedException(); }
+        }
+
+        public void Reset(byte[] buffer, int offset, int count)
+        {
+            _position = 0;
+            _blockBuffer = buffer;
+            _blockOffset = offset;
+            _blockRemaining = count;
+            _numSame = -1;
+            _lastByte = 0;
+            _runBytesOutstanding = 0;
+        }
+
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            int numRead = 0;
+
+            while (numRead < count && _runBytesOutstanding > 0)
+            {
+                int runCount = Math.Min(_runBytesOutstanding, count);
+                for (int i = 0; i < runCount; ++i)
+                {
+                    buffer[offset + numRead] = _lastByte;
+                }
+
+                _runBytesOutstanding -= runCount;
+                numRead += runCount;
+            }
+
+            while (numRead < count && _blockRemaining > 0)
+            {
+                byte b = _blockBuffer[_blockOffset];
+                ++_blockOffset;
+                --_blockRemaining;
+
+                if (_numSame == 4)
+                {
+                    int runCount = Math.Min(b, count - numRead);
+                    for (int i = 0; i < runCount; ++i)
+                    {
+                        buffer[offset + numRead] = _lastByte;
+                        numRead++;
+                    }
+
+                    _runBytesOutstanding = b - runCount;
+                    _numSame = 0;
+                }
+                else
+                {
+                    if (b != _lastByte || _numSame <= 0)
+                    {
+                        _lastByte = b;
+                        _numSame = 0;
+                    }
+
+                    buffer[offset + numRead] = b;
+                    numRead++;
+                    _numSame++;
+                }
+            }
+
+            _position += numRead;
+            return numRead;
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+    }
+}