/*
    * Created on Apr 14, 2004
    *
    */
   package org.neo.swarm.util.io;
   
   import java.io.IOException;
   import java.io.OutputStream;
   import java.nio.ByteBuffer;
  
  /***
   * Provides a ByteBufferOutputStream interface for writing to a socket
   *  @author navery
   */
  public class ByteBufferOutputStream extends OutputStream {
  	
  	StreamCallback callback;	
  	ByteBuffer buffer;
  	
  	public ByteBufferOutputStream(ByteBuffer buffer, StreamCallback callback) {
  	     this.buffer = buffer;
  	     this.callback = callback;
  	}
  	
  	/* (non-Javadoc)
  	 * @see java.io.OutputStream#write(int)
  	 */
  	public void write(int b) throws IOException {
  		checkBuffer(1);
  		buffer.put((byte) b);
  	}
  	
  	/* (non-Javadoc)
  	 * @see java.io.OutputStream#write(byte[])
  	 */
  	public void write(byte[] data) throws IOException {
  		int bytesLeft = data.length;
  		int copyBytes;
  		int pos = 0;
  		while (bytesLeft > 0) {
  			copyBytes = Math.min(buffer.remaining(), bytesLeft);
  			checkBuffer(copyBytes);
  			copyBytes = Math.min(buffer.remaining(), bytesLeft);			
  			buffer.put(data, pos, copyBytes);
  			pos += copyBytes;
  			bytesLeft -= copyBytes;
  		}
  	}
  
  	/* 
  	 * When non blocking this call may write 0 bytes.
  	 * @see java.io.OutputStream#flush()
  	 */
  	public void flush() throws IOException {
  		int bufferSize = this.buffer.position();
  		this.buffer.flip();
  		//this.buffer.rewind();
  		//this.buffer.limit(bufferSize);
  		int written;
  		written = this.callback.execute(this.buffer, bufferSize);
  
  		if (written == 0) {
  			while ((written = this.callback.execute(this.buffer, bufferSize)) == 0) {
  			Thread.yield();
  			try {
  				Thread.sleep(50);
  			} catch (InterruptedException e) {
  				e.printStackTrace();
  			}
  		}
  		}
  		this.buffer.clear();		
  	}
  	/* (non-Javadoc)
  	 * @see java.io.OutputStream#close()
  	 */
  	public void close() throws IOException {
  		this.buffer.clear();
  		this.callback.close();
  	}
  	
  	private void checkBuffer(int sizeRequired)  throws IOException {
  		if (buffer.remaining() <= sizeRequired && buffer.position() > 0) {
  			flush();
  		}
  	}
  }