StreamHelper.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / ManagedLibraries / Remoting / Channels / CORE / StreamHelper.cs / 1305376 / StreamHelper.cs
                        
                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
//============================================================
// 
// File:    StreamHelper.cs 
//
// Summary: Helper methods for streams. 
//
//===========================================================

 
using System;
using System.IO; 
using System.Runtime.Remoting; 
using System.Threading;
 
namespace System.Runtime.Remoting.Channels
{

    internal static class StreamHelper 
    {
        private static AsyncCallback _asyncCopyStreamReadCallback = new AsyncCallback(AsyncCopyStreamReadCallback); 
        private static AsyncCallback _asyncCopyStreamWriteCallback = new AsyncCallback(AsyncCopyStreamWriteCallback); 

        internal static void CopyStream(Stream source, Stream target) 
        {
            if (source == null)
                return;
 
            // see if this is a ChunkedMemoryStream (we can do a direct write)
            ChunkedMemoryStream chunkedMemStream = source as ChunkedMemoryStream; 
            if (chunkedMemStream != null) 
            {
                chunkedMemStream.WriteTo(target); 
            }
            else
            {
                // see if this is a MemoryStream (we can do a direct write) 
                MemoryStream memContentStream = source as MemoryStream;
                if (memContentStream != null) 
                { 
                    memContentStream.WriteTo(target);
                } 
                else
                {
                    // otherwise, we need to copy the data through an intermediate buffer
 
                    byte[] buffer = CoreChannel.BufferPool.GetBuffer();
                    int bufferSize = buffer.Length; 
                    int readCount = source.Read(buffer, 0, bufferSize); 
                    while (readCount > 0)
                    { 
                        target.Write(buffer, 0, readCount);
                        readCount = source.Read(buffer, 0, bufferSize);
                    }
                    CoreChannel.BufferPool.ReturnBuffer(buffer); 
                }
            } 
 
        } // CopyStream
 


        internal static void BufferCopy(byte[] source, int srcOffset,
                                        byte[] dest, int destOffset, 
                                        int count)
        { 
            if (count > 8) 
            {
                Buffer.BlockCopy(source, srcOffset, dest, destOffset, count); 
            }
            else
            {
                for (int co = 0; co < count; co++) 
                    dest[destOffset + co] = source[srcOffset + co];
            } 
                } // BufferCopy 

 


        internal static IAsyncResult BeginAsyncCopyStream(
            Stream source, Stream target, 
            bool asyncRead, bool asyncWrite,
            bool closeSource, bool closeTarget, 
            AsyncCallback callback, Object state) 
        {
            AsyncCopyStreamResult streamState = new AsyncCopyStreamResult(callback, state); 

            byte[] buffer = CoreChannel.BufferPool.GetBuffer();

            streamState.Source = source; 
            streamState.Target = target;
            streamState.Buffer = buffer; 
            streamState.AsyncRead = asyncRead; 
            streamState.AsyncWrite = asyncWrite;
            streamState.CloseSource = closeSource; 
            streamState.CloseTarget = closeTarget;

            try
            { 
                AsyncCopyReadHelper(streamState);
            } 
            catch (Exception e) 
            {
                streamState.SetComplete(null, e); 
            }

            return streamState;
        } // BeginAsyncCopyStream 

        internal static void EndAsyncCopyStream(IAsyncResult iar) 
        { 
            AsyncCopyStreamResult asyncResult = (AsyncCopyStreamResult)iar;
 
            if (!iar.IsCompleted)
            {
                iar.AsyncWaitHandle.WaitOne();
            } 

            if (asyncResult.Exception != null) 
            { 
                throw asyncResult.Exception;
            } 
        } // EndAsyncCopyStream


        private static void AsyncCopyReadHelper(AsyncCopyStreamResult streamState) 
        {
            // There is no try-catch here because the calling method always has a try-catch. 
 
            if (streamState.AsyncRead)
            { 
                byte[] buffer = streamState.Buffer;
                streamState.Source.BeginRead(buffer, 0, buffer.Length, _asyncCopyStreamReadCallback, streamState);
            }
            else 
            {
                byte[] buffer = streamState.Buffer; 
                int bytesRead = streamState.Source.Read(buffer, 0, buffer.Length); 
                if (bytesRead == 0)
                { 
                    streamState.SetComplete(null, null);
                }
                else
                if (bytesRead < 0) 
                {
                    throw new RemotingException( 
                        CoreChannel.GetResourceString("Remoting_Stream_UnknownReadError")); 
                }
                else 
                {
                    AsyncCopyWriteHelper(streamState, bytesRead);
                }
            } 
        } // AsyncCopyReadHelper
 
 
        private static void AsyncCopyWriteHelper(AsyncCopyStreamResult streamState, int bytesRead)
        { 
            // There is no try-catch here because the calling method always has a try-catch.

            if (streamState.AsyncWrite)
            { 
                byte[] buffer = streamState.Buffer;
                streamState.Target.BeginWrite(buffer, 0, bytesRead, _asyncCopyStreamWriteCallback, streamState); 
            } 
            else
            { 
                byte[] buffer = streamState.Buffer;
                streamState.Target.Write(buffer, 0, bytesRead);

                AsyncCopyReadHelper(streamState); 
            }
        } // AsyncCopyWriteHelper 
 

        private static void AsyncCopyStreamReadCallback(IAsyncResult iar) 
        {
            AsyncCopyStreamResult state = (AsyncCopyStreamResult)iar.AsyncState;

            try 
            {
                Stream source = state.Source; 
 
                int bytesRead = source.EndRead(iar);
                if (bytesRead == 0) 
                {
                    state.SetComplete(null, null);
                }
                else 
                if (bytesRead < 0)
                { 
                    throw new RemotingException( 
                        CoreChannel.GetResourceString("Remoting_Stream_UnknownReadError"));
                } 
                else
                {
                    AsyncCopyWriteHelper(state, bytesRead);
                } 
            }
            catch (Exception e) 
            { 
                state.SetComplete(null, e);
            } 
        } // AsyncCopyStreamReadCallback


        private static void AsyncCopyStreamWriteCallback(IAsyncResult iar) 
        {
            AsyncCopyStreamResult state = (AsyncCopyStreamResult)iar.AsyncState; 
 
            try
            { 
                state.Target.EndWrite(iar);

                AsyncCopyReadHelper(state);
            } 
            catch (Exception e)
            { 
                state.SetComplete(null, e); 
            }
        } // AsyncCopyStreamWriteCallback 

    } // class StreamHelper

 

    internal class AsyncCopyStreamResult : BasicAsyncResult 
    { 
        internal Stream Source;
        internal Stream Target; 
        internal byte[] Buffer;
        internal bool AsyncRead;
        internal bool AsyncWrite;
        internal bool CloseSource; 
        internal bool CloseTarget;
 
        internal AsyncCopyStreamResult(AsyncCallback callback, Object state) : 
            base(callback, state)
        { 
        }

        internal override void CleanupOnComplete()
        { 
            if (Buffer != null)
                CoreChannel.BufferPool.ReturnBuffer(Buffer); 
 
            if (CloseSource)
                Source.Close(); 
            if (CloseTarget)
                Target.Close();

        } // CleanupOnComplete 

    } // class AsyncCopyStreamResult 
 

} // namespace System.Runtime.Remoting.Channels 

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