87 lines
2.7 KiB
C#
87 lines
2.7 KiB
C#
//
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// BufferedReadStream.cs
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//
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// Author:
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// Martin Baulig <mabaul@microsoft.com>
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//
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// Copyright (c) 2018 Xamarin Inc. (http://www.xamarin.com)
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// 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 FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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using System;
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using System.IO;
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using System.Threading;
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using System.Threading.Tasks;
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namespace System.Net
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{
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class BufferedReadStream : WebReadStream
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{
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readonly BufferOffsetSize readBuffer;
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public BufferedReadStream (WebOperation operation, Stream innerStream,
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BufferOffsetSize readBuffer)
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: base (operation, innerStream)
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{
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this.readBuffer = readBuffer;
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}
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protected override async Task<int> ProcessReadAsync (
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byte[] buffer, int offset, int size,
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CancellationToken cancellationToken)
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{
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cancellationToken.ThrowIfCancellationRequested ();
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var remaining = readBuffer?.Size ?? 0;
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if (remaining > 0) {
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int copy = (remaining > size) ? size : remaining;
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Buffer.BlockCopy (readBuffer.Buffer, readBuffer.Offset, buffer, offset, copy);
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readBuffer.Offset += copy;
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readBuffer.Size -= copy;
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offset += copy;
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size -= copy;
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return copy;
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}
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if (InnerStream == null)
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return 0;
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return await InnerStream.ReadAsync (
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buffer, offset, size, cancellationToken).ConfigureAwait (false);
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}
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internal bool TryReadFromBuffer (byte[] buffer, int offset, int size, out int result)
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{
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var remaining = readBuffer?.Size ?? 0;
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if (remaining <= 0) {
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result = 0;
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return InnerStream == null;
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}
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int copy = (remaining > size) ? size : remaining;
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Buffer.BlockCopy (readBuffer.Buffer, readBuffer.Offset, buffer, offset, copy);
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readBuffer.Offset += copy;
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readBuffer.Size -= copy;
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offset += copy;
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size -= copy;
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result = copy;
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return true;
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}
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}
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}
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