org.opencms.jlan.CmsFileBuffer Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (C) Alkacon Software (http://www.alkacon.com)
*
* 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.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.jlan;
/**
* Buffer class which holds file contents for JLAN file access in memory before they are written to the VFS.
*
* This is implemented as a CmsByteBuffer instance together with a 'position' index which marks the next write position
*/
public class CmsFileBuffer {
/** The buffer used to store the file contents. */
CmsByteBuffer m_buffer = new CmsByteBuffer(8192);
/** The current write position. */
long m_position;
/**
* Gets the contents of this buffer as a byte array.
*
* @return the file content
*/
public byte[] getContents() {
byte[] contents = new byte[m_buffer.size()];
m_buffer.readBytes(contents, 0, 0, m_buffer.size());
return contents;
}
/**
* Gets the length of the file content.
*
* @return the content length
*
*/
public long getLength() {
return m_buffer.size();
}
/**
* Gets the current write position.
*
* @return the current write position
*/
public long getPosition() {
return m_position;
}
/**
* Initializes the file content data.
*
* @param data the file content data
*/
public void init(byte[] data) {
m_position = 0;
m_buffer.writeBytes(data, 0, 0, data.length);
}
/**
* Transfers data from this buffer to a byte array.
*
* @param dest the target byte array
*
* @param length the number of bytes to transfer
* @param bufferOffset the start index for the target buffer
* @param fileOffset the start index for this instance
*
* @return the number of bytes read, or -1 if we are at the end of the file
*/
public int read(byte[] dest, int length, int bufferOffset, int fileOffset) {
if (fileOffset >= m_buffer.size()) {
return -1;
}
int readEnd = fileOffset + length;
if (readEnd > m_buffer.size()) {
length = length - (readEnd - m_buffer.size());
}
m_buffer.readBytes(dest, fileOffset, bufferOffset, length);
return length;
}
/**
* Changes the write position.
*
* @param newPos the new write position
*/
public void seek(long newPos) {
m_position = newPos;
}
/**
* Changes the size of this buffer.
*
* @param size the new size
*/
public void truncate(int size) {
m_buffer.truncate(size);
m_position = Math.min(size, m_position);
}
/**
* Writes the data to the internal buffer.
*
* @param data the data to write
*/
public void write(byte[] data) {
m_buffer.writeBytes(data, 0, (int)m_position, data.length);
}
}