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javaxdelta - Patch generator and patch tool using the GDIFF algorithm
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/*
 * ByteArraySeekableSource.java
 *
 * Created on May 17, 2006, 12:41 PM
 * Copyright (c) 2006 Heiko Klein
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in 
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */
package com.nothome.delta;

import java.io.IOException;
import java.nio.ByteBuffer;

/**
 * Wraps a byte buffer as a source.
 */
public class ByteBufferSeekableSource implements SeekableSource {
  /** The bb. */
  private ByteBuffer bb;
  /** The cur. */
  private ByteBuffer cur;

  /**
   * Constructs a new ByteArraySeekableSource.
   *
   * @param source the source
   */
  public ByteBufferSeekableSource(byte[] source) {
    this(ByteBuffer.wrap(source));
  }

  /**
   * Constructs a new ByteArraySeekableSource.
   *
   * @param bb the bb
   */
  public ByteBufferSeekableSource(ByteBuffer bb) {
    if (bb == null)
      throw new NullPointerException("bb");
    this.bb = bb;
    bb.rewind();
    try {
      seek(0);
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  /* (non-Javadoc)
   * @see com.nothome.delta.SeekableSource#seek(long)
   */
  @Override
  public void seek(long pos) throws IOException {
    cur = bb.slice();
    if (pos > cur.limit())
      throw new IOException("pos " + pos + " cannot seek " + cur.limit());
    cur.position((int) pos);
  }

  /* (non-Javadoc)
   * @see com.nothome.delta.SeekableSource#read(java.nio.ByteBuffer)
   */
  @Override
  public int read(ByteBuffer dest) throws IOException {
    if (!cur.hasRemaining())
      return -1;
    int c = 0;
    while (cur.hasRemaining() && dest.hasRemaining()) {
      dest.put(cur.get());
      c++;
    }
    return c;
  }

  /* (non-Javadoc)
   * @see java.io.Closeable#close()
   */
  @Override
  public void close() throws IOException {
    bb = null;
    cur = null;
  }

  /**
   * Returns a debug String.
   *
   * @return the string
   */
  @Override
  public String toString() {
    return "BBSeekable" + " bb=" + this.bb.position() + "-" + bb.limit() + " cur=" + this.cur.position() + "-" + cur.limit() + "";
  }
}