83 lines
4.0 KiB
C#
83 lines
4.0 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.Collections.Generic;
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using System.IO;
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namespace DiscUtils.Streams
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{
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/// <summary>
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/// Base class for streams that are essentially a mapping onto a parent stream.
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/// </summary>
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/// <remarks>
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/// This class provides access to the mapping underlying the stream, enabling
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/// callers to convert a byte range in this stream into one or more ranges in
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/// the parent stream.
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/// </remarks>
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public abstract class MappedStream : SparseStream
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{
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/// <summary>
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/// Converts any stream into a non-linear stream.
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/// </summary>
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/// <param name="stream">The stream to convert.</param>
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/// <param name="takeOwnership"><c>true</c> to have the new stream dispose the wrapped
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/// stream when it is disposed.</param>
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/// <returns>A sparse stream.</returns>
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/// <remarks>The wrapped stream is assumed to be a linear stream (such that any byte range
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/// maps directly onto the parent stream).</remarks>
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public new static MappedStream FromStream(Stream stream, Ownership takeOwnership)
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{
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return new WrappingMappedStream<Stream>(stream, takeOwnership, null);
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}
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/// <summary>
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/// Converts any stream into a non-linear stream.
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/// </summary>
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/// <param name="stream">The stream to convert.</param>
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/// <param name="takeOwnership"><c>true</c> to have the new stream dispose the wrapped
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/// stream when it is disposed.</param>
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/// <param name="extents">The set of extents actually stored in <c>stream</c>.</param>
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/// <returns>A sparse stream.</returns>
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/// <remarks>The wrapped stream is assumed to be a linear stream (such that any byte range
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/// maps directly onto the parent stream).</remarks>
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public new static MappedStream FromStream(Stream stream, Ownership takeOwnership,
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IEnumerable<StreamExtent> extents)
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{
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return new WrappingMappedStream<Stream>(stream, takeOwnership, extents);
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}
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/// <summary>
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/// Maps a logical range down to storage locations.
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/// </summary>
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/// <param name="start">The first logical range to map.</param>
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/// <param name="length">The length of the range to map.</param>
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/// <returns>One or more stream extents specifying the storage locations that correspond
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/// to the identified logical extent range.</returns>
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/// <remarks>
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/// <para>As far as possible, the stream extents are returned in logical disk order -
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/// however, due to the nature of non-linear streams, not all of the range may actually
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/// be stored, or some or all of the range may be compressed - thus reading the
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/// returned stream extents is not equivalent to reading the logical disk range.</para>
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/// </remarks>
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public abstract IEnumerable<StreamExtent> MapContent(long start, long length);
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}
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} |