chamilo-lms/main/app_share/SessionRecorder.java

//
//  Copyright (C) 2002 Constantin Kaplinsky.  All Rights Reserved.
//
//  This is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  This software 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 General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this software; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
//  USA.
//

//
// SessionRecorder is a class to write FBS (FrameBuffer Stream) files.
// FBS files are used to save RFB sessions for later playback.
//

import java.io.*;

class SessionRecorder {

  protected FileOutputStream f;
  protected DataOutputStream df;
  protected long startTime, lastTimeOffset;

  protected byte[] buffer;
  protected int bufferSize;
  protected int bufferBytes;

  public SessionRecorder(String name, int bufsize) throws IOException {
    f = new FileOutputStream(name);
    df = new DataOutputStream(f);
    startTime = System.currentTimeMillis();
    lastTimeOffset = 0;
    
    bufferSize = bufsize;
    bufferBytes = 0;
    buffer = new byte[bufferSize];
  }

  public SessionRecorder(String name) throws IOException {
    this(name, 65536);
  }

  //
  // Close the file, free resources.
  //

  public void close() throws IOException {
    try {
      flush();
    } catch (IOException e) {
    }

    df = null;
    f.close();
    f = null;
    buffer = null;
  }

  //
  // Write the FBS file header as defined in the rfbproxy utility.
  //

  public void writeHeader() throws IOException {
    df.write("FBS 001.000\n".getBytes());
  }

  //
  // Write one byte.
  //

  public void writeByte(int b) throws IOException {
    prepareWriting();
    buffer[bufferBytes++] = (byte)b;
  }

  //
  // Write 16-bit value, big-endian.
  //

  public void writeShortBE(int v) throws IOException {
    prepareWriting();
    buffer[bufferBytes++] = (byte)(v >> 8);
    buffer[bufferBytes++] = (byte)v;
  }

  //
  // Write 32-bit value, big-endian.
  //

  public void writeIntBE(int v) throws IOException {
    prepareWriting();
    buffer[bufferBytes]     = (byte)(v >> 24);
    buffer[bufferBytes + 1] = (byte)(v >> 16);
    buffer[bufferBytes + 2] = (byte)(v >> 8);
    buffer[bufferBytes + 3] = (byte)v;
    bufferBytes += 4;
  }

  //
  // Write 16-bit value, little-endian.
  //

  public void writeShortLE(int v) throws IOException {
    prepareWriting();
    buffer[bufferBytes++] = (byte)v;
    buffer[bufferBytes++] = (byte)(v >> 8);
  }

  //
  // Write 32-bit value, little-endian.
  //

  public void writeIntLE(int v) throws IOException {
    prepareWriting();
    buffer[bufferBytes]     = (byte)v;
    buffer[bufferBytes + 1] = (byte)(v >> 8);
    buffer[bufferBytes + 2] = (byte)(v >> 16);
    buffer[bufferBytes + 3] = (byte)(v >> 24);
    bufferBytes += 4;
  }

  //
  // Write byte arrays.
  //

  public void write(byte b[], int off, int len) throws IOException {
    prepareWriting();
    while (len > 0) {
      if (bufferBytes > bufferSize - 4)
	flush(false);

      int partLen;
      if (bufferBytes + len > bufferSize) {
	partLen = bufferSize - bufferBytes;
      } else {
	partLen = len;
      }
      System.arraycopy(b, off, buffer, bufferBytes, partLen);
      bufferBytes += partLen;
      off += partLen;
      len -= partLen;
    }
  }

  public void write(byte b[]) throws IOException {
    write(b, 0, b.length);
  }

  //
  // Flush the output. This method saves buffered data in the
  // underlying file object adding data sizes and timestamps. If the
  // updateTimeOffset is set to false, then the current time offset
  // will not be changed for next write operation.
  //

  public void flush(boolean updateTimeOffset) throws IOException {
    if (bufferBytes > 0) {
      df.writeInt(bufferBytes);
      df.write(buffer, 0, (bufferBytes + 3) & 0x7FFFFFFC);
      df.writeInt((int)lastTimeOffset);
      bufferBytes = 0;
      if (updateTimeOffset)
	lastTimeOffset = -1;
    }
  }

  public void flush() throws IOException {
    flush(true);
  }

  //
  // Before writing any data, remember time offset and flush the
  // buffer before it becomes full.
  //

  protected void prepareWriting() throws IOException {
    if (lastTimeOffset == -1)
      lastTimeOffset = System.currentTimeMillis() - startTime;
    if (bufferBytes > bufferSize - 4)
      flush(false);
  }

}