/*
 * Copyright (c) 2003, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.knopflerfish.bundle.console;

import java.io.*;
import java.util.*;

/**
 * Pipe between Command Input and Output.
 *
 * @author Jan Stein
 * @version $Revision: 1.1.1.1 $
 */
class Pipe extends PrintWriter {
  
  PipeBuffer pipe;

  public Pipe() {
    this(new PipeBuffer());
  }

  Pipe(PipeBuffer p) {
    super(p);
    pipe = p;
  }

  public Reader getReader() {
    return pipe.getReader();
  }

}

class PipeBuffer extends Writer {
  
  private static final int SIZE = 512;
  private char [] buf = new char[SIZE];
  private int size = 0;
  private int rpos = 0;
  private PipeReader pr;
  boolean open = true;

  PipeBuffer() {
    super();
    pr = new PipeReader(this);
  }

  public void write(char cbuf[], int off, int len) throws IOException {
    synchronized (lock) {
      while (len > 0) {
	while (SIZE == size) {
	  try {
	    lock.wait();
	  } catch (InterruptedException e) {
	    throw new IOException("Write interrupted");
	  }
	}
	int clen;
	if (size + len > SIZE) {
	  clen = SIZE - size;
	} else {
	  clen = len;
	}
	int wpos = (rpos + size) % SIZE;
	if (wpos + clen > SIZE) {
	  clen = SIZE - wpos;
	}
	System.arraycopy(cbuf, off, buf, wpos, clen);
	len -= clen;
	off += clen;
	size += clen;
	lock.notifyAll();
      }
    }
  }

  public void flush() {
  }

  public int read(char [] cbuf, int off, int len) throws IOException {
    synchronized (lock) {
      while (open && size < len) {
	try {
	  lock.wait();
	} catch (InterruptedException e) {
	  throw new IOException("Read interrupted");
	}
      }
      if (size < len) {
	len = size;
      }
      int clen;
      if (rpos + len > SIZE) {
	clen = SIZE - rpos;
	System.arraycopy(buf, rpos, cbuf, off, clen);
	rpos = 0;
	off += clen;
	clen = len - clen;
      } else {
	clen = len;
      }
      if (len > 0) {
	System.arraycopy(buf, rpos, cbuf, off, clen);
	rpos += clen;
	size -= len;
	lock.notifyAll();
	int x = (int) cbuf[off];
	return len;
      }
      return -1;
    }
  }

  public void close() throws IOException {
    synchronized (lock) {
      open = false;
      lock.notify();
    }
  }

  public Reader getReader() {
    return pr;
  }
}


class PipeReader extends Reader {

  private PipeBuffer pb;

  public PipeReader(PipeBuffer pb) {
    super();
    this.pb = pb;
  }

  /**
   * Read characters into a portion of an array.
   *
   * @param buf  Output buffer
   * @param off  Offset at which to start storing characters
   * @param len  Maximum number of characters to read
   * @return     The number of characters read, or -1 if end of stream
   * @exception  IOException  If an I/O error occurs
   */
  public int read(char buf[], int off, int len) throws IOException {
    return pb.read(buf, off, len);
  }

  /**
   * Close the stream.
   *
   * @exception  IOException  If an I/O error occurs
   */
  public void close() throws IOException {
    pb.close();
  }

}