src/Net/RefCountedByteBuffer.cs

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//  Copyright (c) Microsoft Corporation
//  All rights reserved. 
//  
//  Licensed under the Apache License, Version 2.0 (the ""License""); you may not use this 
//  file except in compliance with the License. You may obtain a copy of the License at 
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//  limitations under the License.
//  ------------------------------------------------------------------------------------

namespace Amqp
{
    using System;
    using System.Threading;

    class RefCountedByteBuffer : ByteBuffer
    {
        readonly IBufferManager bufferManager;
        int references;

        internal RefCountedByteBuffer(IBufferManager bufferManager, byte[] buffer, int offset, int count, int length)
            : base(buffer, offset, length, count, true)
        {
            this.bufferManager = bufferManager;
            this.references = 1;
        }

        internal IBufferManager BufferManager
        {
            get { return this.bufferManager; }
        }

        internal override void AddReference()
        {
            if (Interlocked.Increment(ref this.references) <= 1)
            {
                Interlocked.Decrement(ref this.references);
                throw new ObjectDisposedException(this.GetType().Name);
            }
        }

        internal override void ReleaseReference()
        {
            if (Interlocked.Decrement(ref this.references) == 0)
            {
                this.bufferManager.ReturnBuffer(this.ToArraySegment());
            }
        }

        internal override void DuplicateBuffer(int bufferSize, int dataSize, out byte[] buffer, out int offset, out int count)
        {
            var segment = this.bufferManager.TakeBuffer(bufferSize);
            buffer = segment.Array;
            offset = segment.Offset;
            count = segment.Count;
            System.Buffer.BlockCopy(this.Buffer, this.Start, segment.Array, segment.Offset, dataSize);
            this.bufferManager.ReturnBuffer(this.ToArraySegment());
        }
    }
}