PinnedBufferMemoryStream.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / IO / PinnedBufferMemoryStream.cs / 1 / PinnedBufferMemoryStream.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Class:  PinnedBufferMemoryStream 
**
** 
** Purpose: Pins a byte[], exposing it as an unmanaged memory
**          stream.  Used in ResourceReader for corner cases.
**
** 
===========================================================*/
using System; 
using System.Runtime.InteropServices; 

namespace System.IO { 
    internal sealed unsafe class PinnedBufferMemoryStream : UnmanagedMemoryStream
    {
        private byte[] _array;
        private GCHandle _pinningHandle; 

        internal PinnedBufferMemoryStream(byte[] array) 
        { 
            BCLDebug.Assert(array != null, "Array can't be null");
 
            int len = array.Length;
            // Handle 0 length byte arrays specially.
            if (len == 0) {
                array = new byte[1]; 
                len = 0;
            } 
 
            _array = array;
            _pinningHandle = new GCHandle(array, GCHandleType.Pinned); 
            // Now the byte[] is pinned for the lifetime of this instance.
            // But I also need to get a pointer to that block of memory...
            fixed(byte* ptr = _array)
                Initialize(ptr, len, len, FileAccess.Read, true); 
        }
 
        ~PinnedBufferMemoryStream() 
        {
            Dispose(false); 
        }

        protected override void Dispose(bool disposing)
        { 
            if (_isOpen) {
                _pinningHandle.Free(); 
                _isOpen = false; 
            }
#if _DEBUG 
            // To help track down lifetime issues on checked builds, force
            //a full GC here.
            if (disposing) {
                GC.Collect(); 
                GC.WaitForPendingFinalizers();
            } 
#endif 
            base.Dispose(disposing);
        } 
    }
}

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