210c7e312b
Added SegmentStream class to assist in maintaining views into portions of the FileStream of the overall mix file to avoid having to copy sections into in-memory buffers.
103 lines
3.2 KiB
C#
103 lines
3.2 KiB
C#
#region Copyright & License Information
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/*
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* Copyright 2007-2015 The OpenRA Developers (see AUTHORS)
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* This file is part of OpenRA, which is free software. It is made
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* available to you under the terms of the GNU General Public License
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* as published by the Free Software Foundation. For more information,
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* see COPYING.
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*/
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#endregion
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using System;
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using System.ComponentModel;
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using System.IO;
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namespace OpenRA.Primitives
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{
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public class SegmentStream : Stream
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{
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public readonly Stream BaseStream;
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public readonly long BaseOffset;
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public readonly long BaseCount;
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public SegmentStream(Stream stream, long offset, long count)
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{
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if (stream == null)
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throw new ArgumentNullException("stream");
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if (!stream.CanSeek)
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throw new ArgumentException("stream must be seekable.", "stream");
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if (offset < 0)
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throw new ArgumentOutOfRangeException("offset", "offset must be non-negative.");
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if (count < 0)
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throw new ArgumentOutOfRangeException("count", "count must be non-negative.");
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BaseStream = stream;
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BaseOffset = offset;
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BaseCount = count;
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stream.Seek(BaseOffset, SeekOrigin.Begin);
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}
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public override bool CanSeek { get { return true; } }
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public override bool CanRead { get { return BaseStream.CanRead; } }
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public override bool CanWrite { get { return BaseStream.CanWrite; } }
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public override long Length { get { return BaseCount; } }
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public override long Position
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{
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get { return BaseStream.Position - BaseOffset; }
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set { BaseStream.Position = BaseOffset + value; }
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}
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public override int Read(byte[] buffer, int offset, int count) { return BaseStream.Read(buffer, offset, count); }
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public override void Write(byte[] buffer, int offset, int count) { BaseStream.Write(buffer, offset, count); }
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public override void Flush() { BaseStream.Flush(); }
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public override long Seek(long offset, SeekOrigin origin)
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{
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switch (origin)
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{
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default: throw new InvalidEnumArgumentException("origin", (int)origin, typeof(SeekOrigin));
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case SeekOrigin.Begin:
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return BaseStream.Seek(BaseOffset + offset, SeekOrigin.Begin) - offset;
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case SeekOrigin.Current:
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return BaseStream.Seek(offset, SeekOrigin.Current) - offset;
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case SeekOrigin.End:
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return BaseStream.Seek(offset, SeekOrigin.End) - offset;
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}
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}
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public override void SetLength(long value) { throw new NotSupportedException(); }
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public override bool CanTimeout { get { return BaseStream.CanTimeout; } }
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public override int ReadTimeout
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{
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get { return BaseStream.ReadTimeout; }
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set { BaseStream.ReadTimeout = value; }
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}
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public override int WriteTimeout
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{
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get { return BaseStream.WriteTimeout; }
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set { BaseStream.WriteTimeout = value; }
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}
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protected override void Dispose(bool disposing)
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{
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if (disposing)
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BaseStream.Dispose();
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base.Dispose(disposing);
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}
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public static long GetOverallNestedOffset(Stream stream, out Stream overallBaseStream)
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{
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var offset = 0L;
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overallBaseStream = stream;
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var segmentStream = stream as SegmentStream;
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if (segmentStream != null)
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offset += segmentStream.BaseOffset + GetOverallNestedOffset(segmentStream.BaseStream, out overallBaseStream);
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return offset;
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}
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}
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}
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