PinnedBufferMemoryStream.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / IO / PinnedBufferMemoryStream.cs / 1305376 / 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; 
using System.Diagnostics.Contracts;

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

        // The new inheritance model requires a Critical default ctor since base (UnmanagedMemoryStream) has one 
        [System.Security.SecurityCritical]
        private PinnedBufferMemoryStream():base(){}

        [System.Security.SecurityCritical]  // auto-generated 
        internal PinnedBufferMemoryStream(byte[] array)
        { 
            Contract.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);
        } 

        [System.Security.SecuritySafeCritical]  // auto-generated
        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);
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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