65 lines
2.0 KiB
C#
65 lines
2.0 KiB
C#
#region Copyright notice and license
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// Protocol Buffers - Google's data interchange format
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// Copyright 2015 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#endregion
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using System;
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using System.IO;
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namespace Google.Protobuf
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{
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/// <summary>
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/// Stream implementation which proxies another stream, only allowing a certain amount
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/// of data to be read. Note that this is only used to read delimited streams, so it
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/// doesn't attempt to implement everything.
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/// </summary>
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internal sealed class LimitedInputStream : Stream
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{
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private readonly Stream proxied;
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private int bytesLeft;
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internal LimitedInputStream(Stream proxied, int size)
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{
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this.proxied = proxied;
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bytesLeft = size;
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}
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public override bool CanRead => true;
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public override bool CanSeek => false;
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public override bool CanWrite => false;
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public override void Flush()
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{
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}
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public override long Length => throw new NotSupportedException();
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public override long Position
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{
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get => throw new NotSupportedException();
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set => throw new NotSupportedException();
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}
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public override int Read(byte[] buffer, int offset, int count)
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{
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if (bytesLeft > 0)
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{
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int bytesRead = proxied.Read(buffer, offset, Math.Min(bytesLeft, count));
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bytesLeft -= bytesRead;
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return bytesRead;
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}
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return 0;
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}
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public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
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public override void SetLength(long value) => throw new NotSupportedException();
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public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
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}
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}
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