DataStreamFromComStream.cs source code in C# .NET

                        Code:
                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / DataStreamFromComStream.cs / 1 / DataStreamFromComStream.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms { 
    using System.Runtime.InteropServices; 

    using System.Diagnostics; 
    using System;
    using System.IO;

 
    /// 
    ///  
    ///  
    /// 
    internal class DataStreamFromComStream : Stream { 

        private UnsafeNativeMethods.IStream comStream;

        public DataStreamFromComStream(UnsafeNativeMethods.IStream comStream) : base() { 
            this.comStream = comStream;
        } 
 
        public override long Position {
            get { 
                return Seek(0, SeekOrigin.Current);
            }

            set { 
                Seek(value, SeekOrigin.Begin);
            } 
        } 

        public override bool CanWrite { 
            get {
                return true;
            }
        } 

        public override bool CanSeek { 
            get { 
                return true;
            } 
        }

        public override bool CanRead {
            get { 
                return true;
            } 
        } 

        public override long Length { 
            get {
                long curPos = this.Position;
                long endPos = Seek(0, SeekOrigin.End);
                this.Position = curPos; 
                return endPos - curPos;
            } 
        } 

        /* 
        private void _NotImpl(string message) {
            NotSupportedException ex = new NotSupportedException(message, new ExternalException(SR.GetString(SR.ExternalException), NativeMethods.E_NOTIMPL));
            throw ex;
        } 
        */
 
        private unsafe int _Read(void* handle, int bytes) { 
            return comStream.Read((IntPtr)handle, bytes);
        } 

        private unsafe int _Write(void* handle, int bytes) {
            return comStream.Write((IntPtr)handle, bytes);
        } 

        public override void Flush() { 
        } 

        public unsafe override int Read(byte[] buffer, int index, int count) { 
            int bytesRead = 0;
            if (count > 0 && index >= 0 && (count + index) <= buffer.Length) {
                fixed (byte* ch = buffer) {
                    bytesRead = _Read((void*)(ch + index), count); 
                }
            } 
            return bytesRead; 
        }
 
        public override void SetLength(long value) {
            comStream.SetSize(value);
        }
 
        public override long Seek(long offset, SeekOrigin origin) {
            return comStream.Seek(offset, (int)origin); 
        } 

        public unsafe override void Write(byte[] buffer, int index, int count) { 
            int bytesWritten = 0;
            if (count > 0 && index >= 0 && (count + index) <= buffer.Length) {
                try {
                    fixed (byte* b = buffer) { 
                        bytesWritten = _Write((void*)(b + index), count);
                    } 
                } 
                catch {
                } 
            }
            if (bytesWritten < count) {
                throw new IOException(SR.GetString(SR.DataStreamWrite));
            } 
        }
 
        protected override void Dispose(bool disposing) { 
            try {
                if (disposing && comStream != null) { 
                    try {
                        comStream.Commit(NativeMethods.STGC_DEFAULT);
                    }
                    catch(Exception) { 
                    }
                } 
                // Can't release a COM stream from the finalizer thread. 
                comStream = null;
            } 
            finally {
                base.Dispose(disposing);
            }
        } 

        ~DataStreamFromComStream() { 
            Dispose(false); 
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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DataStreamFromComStream.cs source code in C# .NET

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