HGlobalSafeHandle.cs source code in C# .NET

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Code:

/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Speech / Src / Internal / HGlobalSafeHandle.cs / 1 / HGlobalSafeHandle.cs

                            //---------------------------------------------------------------------------- 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
//
// Description: 
//		Stream Helper. 
//		Allocates a global memory buffer to do marshaling between a
//		binary and a structured data. The global memory size increases and 
//		never shrinks.
//		

 

 
using System; 
using System.Runtime.InteropServices;
 
namespace System.Speech.Internal
{
    /// 
    /// Encapsulate SafeHandle for Win32 Memory Handles 
    /// 
    internal sealed class HGlobalSafeHandle : SafeHandle 
    { 
        //*******************************************************************
        // 
        // Constructors
        //
        //*******************************************************************
 
        #region Constructors
 
        internal HGlobalSafeHandle () : base (IntPtr.Zero, true) 
        {
        } 

        // This destructor will run only if the Dispose method
        // does not get called.
        ~HGlobalSafeHandle () 
        {
            Dispose (false); 
        } 

        protected override void Dispose (bool disposing) 
        {
            ReleaseHandle ();
            base.Dispose (disposing);
            GC.SuppressFinalize (this); 
        }
 
        #endregion 

        //******************************************************************** 
        //
        // Internal Methods
        //
        //******************************************************************* 

        #region internal Methods 
 
        /// 
        /// 
        /// 
        /// 
        /// 
        internal IntPtr Buffer (int size) 
        {
            if (size > _bufferSize) 
            { 
                if (_bufferSize == 0)
                { 
                    SetHandle (Marshal.AllocHGlobal (size));
                }
                else
                { 
                    SetHandle (Marshal.ReAllocHGlobal (handle, (IntPtr) size));
                } 
 
                GC.AddMemoryPressure (size - _bufferSize);
                _bufferSize = size; 
            }

            return handle;
        } 

        ///  
        /// True if the no memory is allocated 
        /// 
        ///  
        public override bool IsInvalid
        {
            get
            { 
                return handle == IntPtr.Zero;
            } 
        } 

        #endregion 

        //********************************************************************
        //
        // Protected Methods 
        //
        //******************************************************************** 
 
        #region Protected Methods
 
        /// 
        /// Releases the Win32 Memory handle
        /// 
        ///  
        protected override bool ReleaseHandle ()
        { 
            if (handle != IntPtr.Zero) 
            {
                // Reset the extra information given to the GC 
                if (_bufferSize > 0)
                {
                    GC.RemoveMemoryPressure (_bufferSize);
                    _bufferSize = 0; 
                }
 
                Marshal.FreeHGlobal (handle); 
                handle = IntPtr.Zero;
                return true; 
            }

            return false;
        } 

 
        #endregion 

        //******************************************************************* 
        //
        // Private Fields
        //
        //******************************************************************** 

        #region Private Fields 
 
        private int _bufferSize;
 
        #endregion
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
                        

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