123 lines
3.7 KiB
C#
123 lines
3.7 KiB
C#
//
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// Copyright (c) 2008-2011, Kenneth Bell
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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//
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using System;
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using System.IO;
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namespace DiscUtils.Iso9660
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{
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internal class ExtentStream : Stream
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{
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private readonly uint _dataLength;
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private readonly byte _fileUnitSize;
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private readonly byte _interleaveGapSize;
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private readonly Stream _isoStream;
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private long _position;
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private readonly uint _startBlock;
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public ExtentStream(Stream isoStream, uint startBlock, uint dataLength, byte fileUnitSize,
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byte interleaveGapSize)
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{
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_isoStream = isoStream;
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_startBlock = startBlock;
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_dataLength = dataLength;
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_fileUnitSize = fileUnitSize;
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_interleaveGapSize = interleaveGapSize;
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if (_fileUnitSize != 0 || _interleaveGapSize != 0)
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{
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throw new NotSupportedException("Non-contiguous extents not supported");
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}
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}
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public override bool CanRead
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{
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get { return true; }
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}
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public override bool CanSeek
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{
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get { return true; }
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}
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public override bool CanWrite
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{
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get { return false; }
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}
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public override long Length
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{
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get { return _dataLength; }
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}
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public override long Position
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{
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get { return _position; }
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set { _position = value; }
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}
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public override void Flush() {}
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public override int Read(byte[] buffer, int offset, int count)
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{
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if (_position > _dataLength)
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{
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return 0;
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}
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int toRead = (int)Math.Min((uint)count, _dataLength - _position);
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_isoStream.Position = _position + _startBlock * (long)IsoUtilities.SectorSize;
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int numRead = _isoStream.Read(buffer, offset, toRead);
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_position += numRead;
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return numRead;
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}
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public override long Seek(long offset, SeekOrigin origin)
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{
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long newPos = offset;
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if (origin == SeekOrigin.Current)
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{
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newPos += _position;
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}
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else if (origin == SeekOrigin.End)
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{
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newPos += _dataLength;
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}
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_position = newPos;
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return newPos;
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}
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public override void SetLength(long value)
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{
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throw new NotSupportedException();
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}
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public override void Write(byte[] buffer, int offset, int count)
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{
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throw new NotSupportedException();
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}
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}
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} |