NativeBuffer.cs :  » 2.6.4-mono-.net-core » System.Data » System » Data » Odbc » C# / CSharp Open Source

//
// NativeBuffer.cs: class for handling native pointers.
//
// Authors:
//   Brian Ritchie (brianlritchie@hotmail.com)
//   Sureshkumar T <tsureshkumar@novell.com>  2004.
//
// Copyright (C) Brian Ritchie, 2002
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Text;
using System.Data;
using System.Data.Common;

using System.Runtime.InteropServices;

namespace System.Data.Odbc{
        sealed class NativeBuffer : IDisposable
  {
    private IntPtr _ptr;
    private int _length;
    private bool disposed;

    public NativeBuffer ()
    {
    }

    public IntPtr Handle
    {
      get { return _ptr; }
      set { _ptr = value; }
    }

    public int Size
    {
      get { return _length; }
    }

    public void AllocBuffer (int length)
    {
      FreeBuffer ();
      _ptr = Marshal.AllocCoTaskMem (length);
      _length = length;
    }

    public void FreeBuffer ()
    {
      if (_ptr == IntPtr.Zero)
        return;

      Marshal.FreeCoTaskMem (_ptr);
      _length = 0;
      _ptr = IntPtr.Zero;
    }

    public void EnsureAlloc (int length)
    {
      if (Size == length && _ptr != IntPtr.Zero)
        return;
      
      AllocBuffer (length);
    }

    public void Dispose (bool disposing)
    {
      if (disposed)
        return;
      FreeBuffer ();
      _ptr = IntPtr.Zero;
      disposed = true;
    }

    public void Dispose ()
    {
      Dispose (true);
      GC.SuppressFinalize (this);
    }

    ~NativeBuffer ()
    {
      Dispose (false);
    }

    public static implicit operator IntPtr (NativeBuffer buf)
    {
      return buf.Handle;
    }
  }
}