MemoryNetworkFile.java

/*
 * Copyright (C) 2006-2008 Alfresco Software Limited.
 *
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 * As a special exception to the terms and conditions of version 2.0 of 
 * the GPL, you may redistribute this Program in connection with Free/Libre 
 * and Open Source Software ("FLOSS") applications as described in Alfresco's 
 * FLOSS exception.  You should have recieved a copy of the text describing 
 * the FLOSS exception, and it is also available here: 
 * http://www.alfresco.com/legal/licensing"
 */

package org.alfresco.jlan.server.filesys.pseudo;

import java.io.IOException;

import org.alfresco.jlan.server.filesys.FileInfo;
import org.alfresco.jlan.server.filesys.NetworkFile;
import org.alfresco.jlan.smb.SeekType;

/**
 * In Memory Network File Class
 * 
 * <p>
 * In memory network file implementation that uses a memory buffer for the file data.
 * 
 * @author gkspencer
 */
public class MemoryNetworkFile extends NetworkFile {

  // Current file position

  private long m_filePos;

  // File data

  private byte[] m_data;

  /**
   * Class constructor.
   * 
   * @param name String
   * @param data byte[]
   * @param finfo FileInfo
   */
  public MemoryNetworkFile(String name, byte[] data, FileInfo finfo) {

    super(name);

    // Set the file data

    m_data = data;
    if (m_data == null)
      m_data = new byte[0];

    // Set the file size

    setFileSize(m_data.length);

    // Set the creation and modification date/times

    setModifyDate(finfo.getModifyDateTime());
    setCreationDate(finfo.getCreationDateTime());

    // Set the file id and relative path

    if (finfo.getPath() != null) {
      setFileId(finfo.getPath().hashCode());
      setFullName(finfo.getPath());
    }
  }

  /**
   * Close the network file.
   */
  public void closeFile() throws java.io.IOException {

    // Nothing to do
  }

  /**
   * Return the current file position.
   * 
   * @return long
   */
  public long currentPosition() {

    return m_filePos;
  }

  /**
   * Flush the file.
   * 
   * @exception IOException
   */
  public void flushFile()
    throws IOException {

    // Nothing to do
  }

  /**
   * Determine if the end of file has been reached.
   * 
   * @return boolean
   */
  public boolean isEndOfFile()
    throws IOException {

    // Check if we reached end of file

    if (m_filePos == m_data.length)
      return true;
    return false;
  }

  /**
   * Open the file.
   * 
   * @param createFlag boolean
   * @exception IOException
   */
  public void openFile(boolean createFlag)
    throws IOException {

    // Indicate that the file is open

    setClosed(false);
  }

  /**
   * Read from the file.
   * 
   * @param buf byte[]
   * @param len int
   * @param pos int
   * @param fileOff long
   * @return Length of data read.
   * @exception IOException
   */
  public int readFile(byte[] buf, int len, int pos, long fileOff)
    throws IOException {

    // Check if the read is within the file data range

    long fileLen = m_data.length;

    if (fileOff >= fileLen)
      return 0;

    // Calculate the actual read length

    if ((fileOff + len) > fileLen)
      len = (int) (fileLen - fileOff);

    // Copy the data to the user buffer

    System.arraycopy(m_data, (int) fileOff, buf, pos, len);

    // Update the current file position

    m_filePos = fileOff + len;

    // Return the actual length of data read

    return len;
  }

  /**
   * Seek to the specified file position.
   * 
   * @param pos long
   * @param typ int
   * @return long
   * @exception IOException
   */
  public long seekFile(long pos, int typ)
    throws IOException {

    // Seek to the required file position

    switch (typ) {
      // From start of file

      case SeekType.StartOfFile:
        if (currentPosition() != pos)
          m_filePos = pos;
        break;

      // From current position

      case SeekType.CurrentPos:
        m_filePos += pos;
        break;

      // From end of file

      case SeekType.EndOfFile:
        m_filePos += pos;
        if (m_filePos < 0)
          m_filePos = 0L;
        break;
    }

    // Return the new file position

    return currentPosition();
  }

  /**
   * Truncate the file
   * 
   * @param siz long
   * @exception IOException
   */
  public void truncateFile(long siz)
    throws IOException {

    // Allow the truncate, do not alter the pseduo file data
  }

  /**
   * Write a block of data to the file.
   * 
   * @param buf byte[]
   * @param len int
   * @exception IOException
   */
  public void writeFile(byte[] buf, int len, int pos)
    throws IOException {

    // Allow the write, just do not do anything
  }

  /**
   * Write a block of data to the file.
   * 
   * @param buf byte[]
   * @param len int
   * @param pos int
   * @param offset long
   * @exception IOException
   */
  public void writeFile(byte[] buf, int len, int pos, long offset)
    throws IOException {

    // Allow the write, just do not do anything
  }
}