C# Stream.BeginRead方法代码示例

    public StreamByteCounter(Stream src)
    {
        AsyncCallback onEndRead = null;
        onEndRead = delegate(IAsyncResult ar) {
            int c = src.EndRead(ar);
            if (c != 0) {
                lock(this) { pendingReads++; }

                //
                // For each read, we must allocate a new buffer.
                //

                byte[] nb = new byte[CHUNK_SIZE];
                src.BeginRead(nb, 0, nb.Length, onEndRead, nb);

                //
                // The buffer of the current read is passed through the
                // IAsyncResult.AsyncState property.
                //

                byte[] cb = (byte[])ar.AsyncState;

                //
                // Increment occurrence counters.
                //

                lock(this) {
                    for (int i = 0; i < c; i++) {
                        counters[cb[i]]++;
                    }
                }
            }

            //
            // The data of the current read processed; so, decrement
            // the pending counter, and if the counter reaches zero,
            // signal the "done" event.
            //

            lock(this) {
                if (--pendingReads == 0) {
                    done.Set();
                }
            }
        };

        //
        // Allocate the buffer for the first read, and issue it.
        //

        byte[] fb = new byte[CHUNK_SIZE];
        pendingReads = 1;
        src.BeginRead(fb, 0, fb.Length, onEndRead, fb);
    }

 public static bool ReadBeyondEndTest(Stream s)
 {
     Console.WriteLine("Read Beyond End test on "+s.GetType().Name);
     byte[] bytes = new byte[10];
     for(int i=0; i<bytes.Length; i++)
         bytes[i] = (byte) i;
     s.Seek(5, SeekOrigin.End);
     if (s.Position != s.Length + 5)
     {
         iCountErrors++;
         throw new Exception("Position is incorrect!  Seek(5, SeekOrigin.End) should leave us at s.Length + 5, but got: "+s.Position);
     }
     int numRead = s.Read(bytes, 0, bytes.Length);
     if (numRead != 0)
     {
         iCountErrors++ ;
         throw new Exception("Reading from past end of stream is broken!  Expected 0, got: "+numRead);
     }
     for(int i=0; i<bytes.Length; i++)
     {
         if (bytes[i] != (byte) i)
         {
             iCountErrors++ ;
             throw new Exception("Error in byte[] - Read overwrote it!  pos: "+i+"  got: "+bytes[i]);
         }
     }
     numRead = s.ReadByte();
     if (numRead != -1)
     {
         iCountErrors++ ;
         throw new Exception("ReadByte didn't return -1!  got: "+numRead);
     }
     IAsyncResult ar = s.BeginRead(bytes, 0, bytes.Length, null, null);
     numRead = s.EndRead(ar);
     if (numRead != 0)
     {
         iCountErrors++ ;
         throw new Exception("Reading from past end of stream with BeginRead is broken!  Expected 0, got: "+numRead);
     }
     for(int i=0; i<bytes.Length; i++)
         if (bytes[i] != (byte) i)
         {
             iCountErrors++ ;
             throw new Exception("Error in byte[] - BeginRead overwrote it!  pos: "+i+"  got: "+bytes[i]);
         }
     return true;
 }

 public static bool SetLengthTest(Stream s) 
 {
     Console.WriteLine("  (10)  SetLengthTest on "+s.GetType( ).Name);
     if(!s.CanSeek) 
     {
         Console.WriteLine("SetLengthTest shouldn't run on non-seekable stream "+s.GetType( ).Name);
         try 
         {
             s.SetLength(0);
             throw new Exception("SetLength to 0 on a non-seekable stream should have failed!");
         }
         catch(NotSupportedException)	{	}
         return true;
     }
     if(!s.CanWrite) 
     {
         Console.WriteLine("SetLengthTest shouldn't run on non-writable stream "+s.GetType( ).Name);
         try 
         {
             s.SetLength(0);
             throw new Exception("SetLength to 0 on a non-writable stream should have failed!  "
                 +"s.Length: "+s.Length);
         }
         catch(NotSupportedException)	{	}
         return true;
     }
     s.SetLength(0);
     if(s.Length!=0)
         throw new Exception("SetLength to 0, but Length is: "+s.Length);
     if(s.Position!=0)
         throw new Exception("Set length to 0.  Position should be zero too: "+s.Position);
     s.SetLength(10);
     if(s.Length!=10)
         throw new Exception("SetLength to 10, but Length is: "+s.Length);
     if(s.Position!=0)
         throw new Exception("Set length to 10, yet Position should be zero still: "+s.Position);
     if(s.CanRead) 
     {
         byte[]			bytes			= new byte[500];
         IAsyncResult	asyncResult		= s.BeginRead(bytes,0,500,null,null);
         int				numBytes		= s.EndRead(asyncResult);
         if(numBytes!=10)
             throw new Exception("Number of bytes got back from EndRead was wrong!  "
                 +"should have been 10, but got: "+numBytes);
         if(s.Position!=10)
             throw new Exception("After async read, position should be 10, but was: "+s.Position);
     }
     return true;
 }

 public static bool ErrorTest(Stream s) 
 {
     Console.WriteLine("  (09)  Error test on stream: "+s.GetType( ).Name);
     //	Test EndRead & EndWrite's Type safety
     byte[]				bytes		= new byte[0];
     IAsyncResult		asyncResult;
     BogusIAsyncResult	bogus		= new BogusIAsyncResult( );
     if(s.CanRead) 
     {
         asyncResult = s.BeginRead(bytes,0,0,null,null);									/*	BeginRead	*/ 
         try 
         {
             s.EndWrite(asyncResult);													/*	EndWrite	*/ 
             throw new Exception("EndWrite with an asyncResult from BeginRead should have thrown!");
         }
         catch(ArgumentException)	{	}
     }
     if(s.CanWrite) 
     {
         asyncResult=s.BeginWrite(bytes,0,0,null,null);									/*	BeginWrite	*/ 
         try 
         {
             s.EndRead(asyncResult);														/*	EndRead		*/ 
             throw new Exception("EndRead with an asyncResult from BeginWrite should have thrown!");
         }
         catch(ArgumentException)	{	}
         //	Verify EndWrite doesn't allow using the same asyncResult twice.
         s.EndWrite(asyncResult);														/*	EndWrite	*/ 
         try 
         {
             s.EndWrite(asyncResult);													/*	EndWrite	*/ 
             throw new Exception("Exception EndWrite was called twice w/ same IAsyncResult from "
                 +s.GetType( ).Name+", but didn't throw!");
         }
         catch(InvalidOperationException)	{	}
     }
     try 
     {
         s.EndRead(bogus);																/*	EndRead		*/ 
         throw new Exception("EndRead with a bogus IAsyncResult object should have thrown!");
     }
     catch(ArgumentException)	{	}
     try 
     {
         s.EndWrite(bogus);																/*	EndWrite	*/ 
         throw new Exception("EndWrite with a bogus IAsyncResult object should have thrown!");
     }
     catch(ArgumentException)	{	}
     return true;
 }

 public static bool AsyncTest(Stream s) 
 {
     byte[]				bigArr		= new byte[80000];
     byte[]				smArr		= new byte[128];
     int					numBytes;
     AsyncCallback		cb;
     IAsyncResult		asyncResult;
     DateTime			startWait;
     TimeSpan			thirtySecs	= new TimeSpan(0,0,30);
     bool				firstTime;
     TimeSpan			diff;
     if(s.GetType( )==typeof(IsolatedStorageFileStream)) 
     {
         Console.WriteLine("AsyncTest won't run on an IsolatedStorageFileStream "
             +"since it doesn't support async operations.");
         return true;
     }
     Console.WriteLine("  (08)  Async test on "+s.GetType( ).Name);
     if(s.Position!=0)
         throw new Exception("AsyncTest assumes stream's position will be 0 when starting.");
     for(int i=0;i<smArr.Length;i++)		smArr[i] = (byte)i;
     //	Try writing something more than 64KB so we have a chance of doing an async write.
     for(int i=0;i<bigArr.Length;i++)	bigArr[i] = (byte)((i%26)+(byte)'A');
     //	Ensure that we do run our async callback at some point.
     didAsyncCallbackRun=false;
     cb = new AsyncCallback(AsyncTestCallback);
     asyncResult=s.BeginWrite(smArr,0,smArr.Length,cb,String.Empty);						/*	BeginWrite	*/ 
     s.EndWrite(asyncResult);															/*	EndWrite	*/ 
     if(s.Position!=smArr.Length)
         throw new Exception("After first BeginWrite call, (s.Position!=smArr.Length)  got: "
             +s.Position);
     asyncResult=s.BeginWrite(bigArr,0,bigArr.Length,null,String.Empty);
     s.EndWrite(asyncResult);
     if(s.Position!=bigArr.Length+smArr.Length)
         throw new Exception("After second BeginWrite call, s.Position wasn't right!  expected: "
             +(bigArr.Length+smArr.Length)+"  got: "+s.Position);
     //	And to be sure things work, test write with an offset.
     asyncResult=s.BeginWrite(smArr,smArr.Length/2,smArr.Length/2,null,null);			/*	BeginWrite	*/ 
     s.EndWrite(asyncResult);															/*	EndWrite	*/ 
     if(s.Position!=(smArr.Length/2+bigArr.Length+smArr.Length))
         throw new Exception("After third BeginWrite call, s.Position wasn't correct! expected: "
             +(smArr.Length/2+bigArr.Length+smArr.Length)
             +"  got: "+s.Position);
     startWait=DateTime.Now;
     firstTime=true;
     while(!didAsyncCallbackRun) 
     {
         if(firstTime) 
         {
             Console.WriteLine("Waiting for async callback to be run from first BeginWrite call.");
             firstTime=false;
         }
         else
             Console.Write(".");
         Thread.Sleep(20);
         diff=DateTime.Now-startWait;
         if(diff>thirtySecs)
             throw new Exception("Async callback didn't run yet after 2 BeginWRITE calls and "
                 +"30 seconds of blocking!  "
                 +"This could be a bug in a particular stream class, "
                 +"or an extremely pathetic race condition in this test.");
     }
     didAsyncCallbackRun=false;
     s.Position=0;
     byte[]		input	= new byte[(int)s.Length];
     //	Retest running the async callback here.
     asyncResult=s.BeginRead(input,0,smArr.Length,cb,String.Empty);						/*	BeginRead	*/ 
     numBytes=s.EndRead(asyncResult);													/*	BeginRead	*/ 
     if(numBytes!=smArr.Length)
         throw new Exception("After first BeginRead call, (numBytes!=smArr.Length)  got: "
             +numBytes);
     if(s.Position!=smArr.Length)
         throw new Exception("After first BeginRead call, (s.Position!=smArr.Length)  got: "
             +s.Position);
     asyncResult=s.BeginRead(input,smArr.Length,bigArr.Length,null,String.Empty);		/*	BeginRead	*/ 
     numBytes=s.EndRead(asyncResult);													/*	EndRead		*/ 
     if(numBytes!=bigArr.Length)
         throw new Exception("After second BeginRead call, (numBytes!=bigArr.Length)  got: "
             +numBytes);
     if(s.Position!=bigArr.Length+smArr.Length)
         throw new Exception("After second BeginRead call, s.Position wasn't right!  expected: "
             +(bigArr.Length+smArr.Length)+"  got: "+s.Position);
     asyncResult=s.BeginRead(input,smArr.Length+bigArr.Length,smArr.Length/2,null,null);	/*	BeginRead	*/ 
     numBytes=s.EndRead(asyncResult);													/*	EndRead		*/ 
     if(numBytes!=smArr.Length/2)
         throw new Exception("After third BeginRead call, (numBytes!=smArr.Length/2)  got: "
             +numBytes);
     if(s.Position!=(smArr.Length/2+bigArr.Length+smArr.Length))
         throw new Exception("After third BeginRead call, s.Position wasn't correct! expected: "
             +(smArr.Length/2+bigArr.Length+smArr.Length)
             +"  got: "+s.Position);
     for(int i=0;i<smArr.Length;i++)
         if (smArr[i]!=input[i])
             throw new Exception("When reading first smArr copy, position "
                 +i+" was wrong!  got: "
                 +input[i]+"  expected: "+smArr[i]);
     int		offset	= smArr.Length;
     for(int i=0;i<bigArr.Length;i++)
         if (bigArr[i]!=input[i+offset])
             throw new Exception("When reading bigArr copy, position "
//.........这里部分代码省略.........

 public static bool CanPropertiesTest(Stream s) 
 {
     Console.WriteLine("  (06)  Can-Properties Test on "+s.GetType( ).Name);
     byte[]			bytes				= new byte[1];
     int				bytesTransferred;
     IAsyncResult	asyncResult;
     if(s.CanRead) 
     {			//	Ensure all Read methods work, if CanRead is true.
         int		n	= s.ReadByte( );
         if(n==-1)
             throw new Exception("On a readable stream, ReadByte returned -1...");
         bytesTransferred=s.Read(bytes,0,1);
         if(bytesTransferred!=1)
             throw new Exception("Read(byte[],0,1) should have returned 1!  got: "+bytesTransferred);
         asyncResult=s.BeginRead(bytes,0,1,null,null);									/*	BeginRead	*/ 
         bytesTransferred=s.EndRead(asyncResult);										/*	EndRead		*/ 
         if(bytesTransferred!=1)
             throw new Exception("BeginRead(byte[],0,1) should have returned 1!  got: "
                 +bytesTransferred);
     }						//	End of (s.CanRead) Block
     else 
     {					//	Begin of (!s.CanRead) Block
         try 
         {
             s.ReadByte( );
             throw new Exception("ReadByte on an unreadable stream should have thrown!");
         }
         catch(NotSupportedException)	{	}
         try 
         {
             s.Read(bytes,0,1);
             throw new Exception("Read(bytes,0,1) on an unreadable stream should have thrown!");
         }
         catch(NotSupportedException)	{	}
         try 
         {
             s.BeginRead(bytes,0,1,null,null);											/*	BeginRead	*/ 
             throw new Exception("BeginRead on an unreadable stream should have thrown!");
         }
         catch(NotSupportedException)	{	}
     }						//	End of (!s.CanRead) Block
     if(s.CanWrite) 
     {		//	Ensure write methods work if CanWrite returns true.
         s.WriteByte(0);
         s.Write(bytes,0,1);
         asyncResult = s.BeginWrite(bytes,0,1,null,null);								/*	BeginWrite	*/ 
         s.EndWrite(asyncResult);														/*	EndWrite	*/ 
     }						//	End of (s.CanWrite) Block
     else 
     {					//	Begin of (!s.CanWrite) Block
         try 
         {
             s.WriteByte(2);
             throw new Exception("WriteByte on an unreadable stream should have thrown!");
         }
         catch(NotSupportedException)	{	}
         try 
         {
             s.Write(bytes,0,1);
             throw new Exception("Write(bytes,0,1) on an unreadable stream should have thrown!");
         }
         catch(NotSupportedException)	{	}
         try 
         {
             s.BeginWrite(bytes,0,1,null,null);											/*	BeginWrite	*/ 
             throw new Exception("BeginWrite on an unreadable stream should have thrown!");
         }
         catch(NotSupportedException)	{	}
     }						//	End of (!s.CanWrite) Block
     if(s.CanSeek) 
     {			//	Ensure length-related methods work if CanSeek returns true
         long	n	= s.Length;
         n=s.Position;
         if(s.Position>s.Length)
             throw new Exception("Position is beyond the length of the stream!");
         s.Position=0;
         s.Position=s.Length;
         if(s.Position!=s.Seek(0,SeekOrigin.Current))
             throw new Exception("s.Position!=s.Seek(0,SeekOrigin.Current)");
         if(s.CanWrite)		//	Verify you can set the length, if it's writable.
             s.SetLength(s.Length);
     }						//	End of (s.CanSeek) Block
     else 
     {					//	Begin of (!s.CanSeek) Block
         try 
         {
             s.Position=5;
             throw new Exception("set_Position should throw on a non-seekable stream!");
         }
         catch(NotSupportedException)	{	}
         try 
         {
             long	n	= s.Position;
             throw new Exception("get_Position should throw on a non-seekable stream!");
         }
         catch(NotSupportedException)	{	}
         try 
         {
             long	n	= s.Length;
             throw new Exception("get_Length should throw on a non-seekable stream!");
//.........这里部分代码省略.........

//.........这里部分代码省略.........
		for(int i=0; i<iLength;i++)
			chArr[i] = (Char)i;
		bw1.Write(chArr);
		bw1.Write(chArr, 512, 512);
		bw1.Write(new String(chArr));
		bw1.Write(new String(chArr));
		stream.Seek(0, SeekOrigin.Begin);
		for(int i=0; i<iLength; i++){
			if(stream.ReadByte() != i%256){
                return false;
            }
		}
		btArr = new Byte[iLength];
		stream.Read(btArr, 0, iLength);
		for(int i=0; i<iLength; i++){
			if(btArr[i] != (Byte)i){
				Console.WriteLine(i + " "  + btArr[i] + " " + (Byte)i);
				return false;
			}
		}
		BinaryReader br1 = new BinaryReader(stream);
		if(br1.ReadBoolean())
			return false;
		if(!br1.ReadBoolean())
			return false;
		for(int i=0; i<10; i++){
			if(br1.ReadByte() != (Byte)i)
			return false;
			if(br1.ReadSByte() != (SByte)i)
			return false;
			if(br1.ReadInt16() != (Int16)i)
			return false;
			if(br1.ReadChar() != (Char)i)
			return false;
			if(br1.ReadUInt16() != (UInt16)i)
			return false;
			if(br1.ReadInt32() != i)
			return false;
			if(br1.ReadUInt32() != (UInt32)i)
			return false;
			if(br1.ReadInt64() != (Int64)i)
			return false;
			if(br1.ReadUInt64() != (UInt64)i)
			return false;
			if(br1.ReadSingle() != (Single)i)
			return false;
			if(br1.ReadDouble() != (Double)i)
			return false;
		}
		chArr = br1.ReadChars(iLength);
		for(int i=0; i<iLength;i++){
			if(chArr[i] != (Char)i)
			return false;
		}
		chArr = new Char[512];
		chArr = br1.ReadChars(iLength/2);
		for(int i=0; i<iLength/2;i++){
			if(chArr[i] != (Char)(iLength/2+i))
			return false;
		}
		chArr = new Char[iLength];
		for(int i=0; i<iLength;i++)
			chArr[i] = (Char)i;
		strValue = br1.ReadString();
		if(!strValue.Equals(new String(chArr)))
			return false;
		strValue = br1.ReadString();
		if(!strValue.Equals(new String(chArr))){
            return false;
        }
		try{
			stream.Seek(1, SeekOrigin.Current);
			return true;
			}catch(Exception){
		}
		stream.Position =  0;
		btArr = new Byte[iLength];
		for(int i=0; i<iLength; i++)
			btArr[i] = (Byte)(i + 5);
		AsyncCallback acb1 = new AsyncCallback(new Co3965StreamMethods().AsyncTestCB);
		IAsyncResult isync1 = stream.BeginWrite(btArr, 0, btArr.Length, acb1, stream.GetType().ToString());
		stream.EndWrite(isync1);
		stream.Position = 0;
		for(int i=0; i<iLength; i++){
			if(stream.ReadByte() != (Byte)(i+5))
			return false;
		}
		stream.Position = 0;
		AsyncCallback acb2 = new AsyncCallback(new Co3965StreamMethods().AsyncTestCB);
		Byte[] btArr1 = new Byte[iLength];
		IAsyncResult isync2 = stream.BeginRead(btArr1, 0, btArr1.Length, acb2, stream.GetType().ToString());
		iValue = stream.EndRead(isync2);
		if(iValue!=btArr.Length)
			return false;
		for(int i=0; i<iLength; i++){
			if(btArr[i] != btArr1[i])
				return false;
		}
		return true;
	}

        private void AcceptCompleted(IAsyncResult ar)
        {
            // Connect to this client
             m_client = m_server.EndAcceptTcpClient(ar);

             // Accept another client
             new ClientConnectionApm(m_server);

             // Start processing this client
             m_stream = m_client.GetStream();
             // Read 1 byte from client which contains length of additional data
             m_stream.BeginRead(m_inputData, 0, 1, ReadLengthCompleted, null);
        }

    //
    // File copy using APM performs asynchronous reads and asynchronous
    // write operations.
    //
    static long ApmFileCopy2(Stream src, Stream dst)
    {
        var done = new ManualResetEventSlim(false);
        long fileSize = 0;
        IOException ioex = null;
        int pendingWrites = 1;		// Account for the last read of 0 bytes.
        AsyncCallback onReadCompleted = null, onWriteCompleted = null;

        onReadCompleted = delegate (IAsyncResult ar) {
            int bytesRead = 0;
            byte[] _rbuffer = (byte[])ar.AsyncState;
            try {
                bytesRead = src.EndRead(ar);
            } catch (IOException _ioex) {
                src.Close();
                dst.Close();
                ioex = _ioex;
                done.Set();
                return;
            }
            if (bytesRead != 0) {

                //
                // Allocate a buffer for the next read, and start write the current
                // read buffer.
                //

                var writeFrom = (byte[])ar.AsyncState;

                //
                // Increment the pending writes counter and start writing
                // the current read block.
                //

                Interlocked.Increment(ref pendingWrites);
                dst.BeginWrite(writeFrom, 0, bytesRead, onWriteCompleted, bytesRead);

                //
                // After the write is taking place, start a new read.
                // We ensure that the read block are written with the proper order.
                //

                var readTo = new byte[BUFFER_SIZE];
                src.BeginRead(readTo, 0, readTo.Length, onReadCompleted, readTo);
            } else {

                // End of source file.

                src.Close();

                //
                // Decrement the pending writes count and terminate copy if
                // all writes are done.
                //

                if (Interlocked.Decrement(ref pendingWrites) == 0) {

                    //
                    // No writes are pending, close the destination file and
                    // set the *done* event.
                    //

                    dst.Close();
                    done.Set();
                }
            }
        };

        onWriteCompleted = delegate (IAsyncResult ar) {
            int bytesWritten = (int)ar.AsyncState;
            try {
                dst.EndWrite(ar);
                fileSize += bytesWritten;
            } catch (IOException _ioex) {
                dst.Close();
                src.Close();
                ioex = _ioex;
                done.Set();
                return;
            }

            //
            // Decrement the pending writes count and terminate copy if
            // all writes are done.
            //

            if (Interlocked.Decrement(ref pendingWrites) == 0) {

                //
                // No writes are pending, close the destination file and
                // set the *done* event.
                //

                dst.Close();
                done.Set();
            }
//.........这里部分代码省略.........

    //
    // File copy using APM asynchronous read and synchronous write operations.
    //
    static long ApmFileCopy(Stream src, Stream dst)
    {
        var done = new ManualResetEventSlim(false);
        long fileSize = 0;
        IOException ioex = null;
        AsyncCallback onReadCompleted = null;
        onReadCompleted = delegate(IAsyncResult iar) {
            int bytesRead = 0;
            try {
                bytesRead = src.EndRead(iar);
            } catch (IOException _ioex) {
                src.Close();
                dst.Close();
                ioex = _ioex;
                done.Set();
                return;
            }
            if (bytesRead != 0) {

                //
                // The read buffer is passed through IasyncResult.AsyncState.
                // Allocate a new buffer for the next read and issue an synchronous write.
                //
                // The lock ensures that we can't process the completion of the new read
                // completion before terminate the current write.
                //

                var writeFrom = (byte[])iar.AsyncState;
                var readTo = new byte[BUFFER_SIZE];
                lock(dst) {
                    src.BeginRead(readTo, 0, readTo.Length, onReadCompleted, readTo);
                    dst.Write(writeFrom, 0, bytesRead);
                    fileSize += bytesRead;
                }
            } else {

                //
                // We reach the EOF on the source stream.
                // We must ensure that the write of the last block is done,
                // before close the destination stream and set the event.
                //

                src.Close();
                lock(dst) {}
                dst.Close();
                done.Set();
                return;
            }
        };

        //
        // Start the copy process, issuingthe first asynchronous read.
        //

        var firstBuf = new byte[BUFFER_SIZE];
        src.BeginRead(firstBuf, 0, firstBuf.Length, onReadCompleted, firstBuf);

        // Wait until completion.

        done.Wait();
        if (ioex != null) {
            throw ioex;
        }
        return fileSize;
    }