/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions Copyright [year] [name of copyright owner]".
 *
 * Copyright 2006-2008 Sun Microsystems, Inc.
 * Portions Copyright 2013-2014 ForgeRock AS.
 */
package org.opends.server.replication.service;

import java.io.IOException;
import java.io.InputStream;

/**
 * This class creates an input stream that can be used to read entries generated
 * by SynchroLDIF as if they were being read from another source like a file.
 */
class ReplInputStream extends InputStream
{
  /** Indicates whether this input stream has been closed. */
  private boolean closed;

  /** The domain associated to this import. */
  private final ReplicationDomain domain;

  private byte[] bytes;
  private int index;

  /**
   * Creates a new ReplLDIFInputStream that will import entries
   * for a synchronization domain.
   *
   * @param domain The replication domain
   */
  ReplInputStream(ReplicationDomain domain)
  {
    this.domain = domain;
    closed      = false;
  }

  /**
   * Closes this input stream so that no more data may be read from it.
   */
  @Override
  public void close()
  {
    closed      = true;
  }

  /**
   * Reads data from this input stream.
   *
   * @param  b    The array into which the data should be read.
   * @param  off  The position in the array at which point the data read may be
   *              placed.
   * @param  len  The maximum number of bytes that may be read into the
   *              provided array.
   *
   * @return  The number of bytes read from the input stream into the provided
   *          array, or -1 if the end of the stream has been reached.
   *
   * @throws  IOException  If a problem has occurred while generating data for
   *                       use by this input stream.
   */
  @Override
  public int read(byte[] b, int off, int len) throws IOException
  {
    if (closed)
    {
      return -1;
    }

    int receivedLength;
    int copiedLength;

    if (bytes == null)
    {
      // First time this method is called or the previous entry was
      // finished. Read a new entry and return it.
      bytes = domain.receiveEntryBytes();

      if (bytes==null)
      {
        closed = true;
        return -1;
      }

      receivedLength = bytes.length;
      index = 0;
    }
    else
    {
      // Some data was left from the previous entry, feed the read with this
      // data.
      receivedLength = bytes.length - index;
    }

    if (receivedLength <= len)
    {
      copiedLength = receivedLength;
    }
    else
    {
      copiedLength = len;
    }

    System.arraycopy(bytes, index, b, off, copiedLength);
    index += copiedLength;

    if (index == bytes.length)
    {
      bytes = null;
    }

    return copiedLength;
  }

  /**
   * Reads a single byte of data from this input stream.
   *
   * @return  The byte read from the input stream, or -1 if the end of the
   *          stream has been reached.
   *
   * @throws  IOException  If a problem has occurred while generating data for
   *                       use by this input stream.
   */
  @Override
  public int read() throws IOException
  {
    if (closed) {
      return -1;
    }

    byte[] b = new byte[1];

    if (read(b, 0, 1) == 0) {
      throw new IOException();
    }

    return b[0];
  }
}