Initial commit - WPinternals 2.6

DiscUtils/MirrorStream.cs

@@ -0,0 +1,175 @@
+//
+// 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.
+//
+
+namespace DiscUtils
+{
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+
+    internal class MirrorStream : SparseStream
+    {
+        private List<SparseStream> _wrapped;
+        private Ownership _ownsWrapped;
+        private bool _canRead;
+        private bool _canWrite;
+        private bool _canSeek;
+        private long _length;
+
+        public MirrorStream(Ownership ownsWrapped, params SparseStream[] wrapped)
+        {
+            _wrapped = new List<SparseStream>(wrapped);
+            _ownsWrapped = ownsWrapped;
+
+            _canRead = _wrapped[0].CanRead;
+            _canWrite = _wrapped[0].CanWrite;
+            _canSeek = _wrapped[0].CanSeek;
+            _length = _wrapped[0].Length;
+
+            foreach (var stream in _wrapped)
+            {
+                if (stream.CanRead != _canRead || stream.CanWrite != _canWrite || stream.CanSeek != _canSeek)
+                {
+                    throw new ArgumentException("All mirrored streams must have the same read/write/seek permissions", "wrapped");
+                }
+
+                if (stream.Length != _length)
+                {
+                    throw new ArgumentException("All mirrored streams must have the same length", "wrapped");
+                }
+            }
+        }
+
+        public override bool CanRead
+        {
+            get { return _canRead; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return _canSeek; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return _canWrite; }
+        }
+
+        public override long Length
+        {
+            get { return _length; }
+        }
+
+        public override long Position
+        {
+            get
+            {
+                return _wrapped[0].Position;
+            }
+
+            set
+            {
+                _wrapped[0].Position = value;
+            }
+        }
+
+        public override IEnumerable<StreamExtent> Extents
+        {
+            get { return _wrapped[0].Extents; }
+        }
+
+        public override void Flush()
+        {
+            _wrapped[0].Flush();
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            return _wrapped[0].Read(buffer, offset, count);
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            return _wrapped[0].Seek(offset, origin);
+        }
+
+        public override void SetLength(long value)
+        {
+            if (value != _length)
+            {
+                throw new InvalidOperationException("Changing the stream length is not permitted for mirrored streams");
+            }
+        }
+
+        public override void Clear(int count)
+        {
+            long pos = _wrapped[0].Position;
+
+            if (pos + count > _length)
+            {
+                throw new IOException("Attempt to clear beyond end of mirrored stream");
+            }
+
+            foreach (var stream in _wrapped)
+            {
+                stream.Position = pos;
+                stream.Clear(count);
+            }
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            long pos = _wrapped[0].Position;
+
+            if (pos + count > _length)
+            {
+                throw new IOException("Attempt to write beyond end of mirrored stream");
+            }
+
+            foreach (var stream in _wrapped)
+            {
+                stream.Position = pos;
+                stream.Write(buffer, offset, count);
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (disposing && _ownsWrapped == Ownership.Dispose && _wrapped != null)
+                {
+                    foreach (var stream in _wrapped)
+                    {
+                        stream.Dispose();
+                    }
+
+                    _wrapped = null;
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+    }
+}