RecordedInputStream.java

/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Contact info: lobochief@users.sourceforge.net
 */
/*
 * Created on Apr 15, 2005
 */
package org.lobobrowser.util.io;

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

/**
 * Wraps an InputStream and records all of the bytes read. This stream supports
 * mark() and reset().
 * <p>
 * Note: Buffered streams should wrap this class as opposed to the other way
 * around.
 *
 * @author J. H. S.
 */
public class RecordedInputStream extends InputStream {
  private final InputStream delegate;
  private final ByteArrayOutputStream store = new ByteArrayOutputStream();
  private final int maxBufferSize;
  private boolean hasReachedEOF = false;
  private boolean hasReachedMaxBufferSize = false;
  private int markPosition = -1;
  private int readPosition = -1;
  private byte[] resetBuffer = null;

  /**
   *
   */
  public RecordedInputStream(final InputStream delegate, final int maxBufferSize) {
    super();
    this.delegate = delegate;
    this.maxBufferSize = maxBufferSize;
  }

  /*
   * (non-Javadoc)
   *
   * @see java.io.InputStream#read()
   */
  @Override
  public int read() throws IOException {
    if ((this.readPosition != -1) && (this.readPosition < this.resetBuffer.length)) {
      final int b = this.resetBuffer[this.readPosition];
      this.readPosition++;
      return b;
    } else {
      final int b = this.delegate.read();
      if (b != -1) {
        if (!this.hasReachedMaxBufferSize) {
          this.store.write(b);
          if (this.store.size() > this.maxBufferSize) {
            this.hasReachedMaxBufferSize = true;
          }
        }
      } else {
        this.hasReachedEOF = true;
      }
      return b;
    }
  }

  /*
   * (non-Javadoc)
   *
   * @see java.io.InputStream#available()
   */
  @Override
  public int available() throws IOException {
    return this.delegate.available();
  }

  /*
   * (non-Javadoc)
   *
   * @see java.io.InputStream#close()
   */
  @Override
  public void close() throws IOException {
    this.delegate.close();
  }

  /*
   * (non-Javadoc)
   *
   * @see java.io.InputStream#markSupported()
   */
  @Override
  public boolean markSupported() {
    return true;
  }

  @Override
  public synchronized void mark(final int readlimit) {
    if (this.hasReachedMaxBufferSize) {
      throw new java.lang.IllegalStateException("Maximum buffer size was already reached.");
    }
    this.markPosition = this.store.size();
  }

  @Override
  public synchronized void reset() throws IOException {
    if (this.hasReachedMaxBufferSize) {
      throw new java.lang.IllegalStateException("Maximum buffer size was already reached.");
    }
    final int mp = this.markPosition;
    final byte[] wholeBuffer = this.store.toByteArray();
    final byte[] resetBuffer = new byte[wholeBuffer.length - mp];
    System.arraycopy(wholeBuffer, mp, resetBuffer, 0, resetBuffer.length);
    this.resetBuffer = resetBuffer;
    this.readPosition = 0;
  }

  /*
   * (non-Javadoc)
   *
   * @see java.io.InputStream#read(byte[], int, int)
   */
  @Override
  public int read(final byte[] buffer, final int offset, final int length) throws IOException {
    if ((this.readPosition != -1) && (this.readPosition < this.resetBuffer.length)) {
      final int minLength = Math.min(this.resetBuffer.length - this.readPosition, length);
      System.arraycopy(this.resetBuffer, this.readPosition, buffer, offset, minLength);
      this.readPosition += minLength;
      return minLength;
    } else {
      final int numRead = this.delegate.read(buffer, offset, length);
      if (numRead != -1) {
        if (!this.hasReachedMaxBufferSize) {
          this.store.write(buffer, offset, numRead);
          if (this.store.size() > this.maxBufferSize) {
            this.hasReachedMaxBufferSize = true;
          }
        }
      } else {
        this.hasReachedEOF = true;
      }
      return numRead;
    }
  }

  public void consumeToEOF() throws IOException {
    final byte[] buffer = new byte[8192];
    while (this.read(buffer) != -1) {
      // EMPTY LOOP
    }
  }

  public byte[] getBytesRead() throws BufferExceededException {
    if (this.hasReachedMaxBufferSize) {
      throw new BufferExceededException();
    }
    return this.store.toByteArray();
  }

  public String getString(final String encoding) throws java.io.UnsupportedEncodingException, BufferExceededException {
    if (this.hasReachedMaxBufferSize) {
      throw new BufferExceededException();
    }
    final byte[] bytes = this.store.toByteArray();
    return new String(bytes, encoding);
  }

  public boolean hasReachedEOF() {
    return this.hasReachedEOF;
  }
}