<?php
/*=====================================================================*\
|| ###################################################################
|| # Bugdar
|| # Copyright (c)2004-2009 Blue Static
|| #
|| # 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; version 2 of the License.
|| #
|| # 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
|| ###################################################################
\*=====================================================================*/

/**
 * Message Object File Reader (.mo reader)
 *
 * Reads a MO file that is used by gettext but without needing the gettext
 * extension. The format is detailed here:
 * http://www.gnu.org/software/gettext/manual/html_node/MO-Files.html
 *
 * @author		rsesek
 * @copyright	Copyright (c)2006 - 2009, Blue Static
 * @package		Bugdar
 *
 */
class MOReader
{
	/**
	 * The name of the file to use
	 * @var string
	 */
	var $filename;
	
	/**
	 * The file pointer of the MO file
	 * @var resource
	 */
	var $file = null;
	
	/**
	 * Is the MO file a big endian one?
	 * @var boolean
	 */
	var $bigEndian = false;
	
	/**
	 * The string table as an array
	 * @var array
	 */
	var $strings = array();
	
	/**
	 * Creates a new MOReader given a path to a MO file
	 */
	function MOReader($filename)
	{
		$this->filename = $filename;
		$this->_loadFile();
	}
	
	/**
	 * Returns the translated string for T, or the original if none exists
	 * 
	 * @param	string	Native string to look up a translation for
	 *
	 * @return	string
	 */
	function T($str)
	{
		if (empty($this->strings[$str]))
		{
			return $str;
		}
		return $this->strings[$str];
	}
	
	/**
	 * Reads $size number of bytes
	 * 
	 * @param	integer	Number of bytes to read
	 *
	 * @return	string
	 */
	function _readBytes($size)
	{
		$stream = fread($this->file, 4 * $size);
		if ($this->bigEndian)
		{
			return unpack('N' . $size, $stream);
		}
		else
		{
			return unpack('V' . $size, $stream);
		}
	}
	
	/**
	 * Lodas the MO data information into the stirng table
	 */
	function _loadFile()
	{
		$this->file = @fopen($this->filename, 'r');
		if (!$this->file)
		{
			BSApp::debug("could not open MO file {$this->filename}");
			return;
		}
		
		// read the magic number
		$stream = $this->_readBytes(1);
		$stream = dechex($stream[1]);
		if ($stream == '950412de')
		{
			$this->bigEndian = false;
		}
		else if ($stream == 'de120495')
		{
			$this->bigEndian = true;
		}
		else
		{
			throw new Exception('Invalid MO file format');
		}
		
		// read the revision (unused in MOs)
		$this->_readBytes(1);
		
		// read the number of strings
		$count = $this->_readBytes(1);
		$count = $count[1];
		
		// get the start positions of the original and translated tables
		$offsetO = $this->_readBytes(1);
		$offsetT = $this->_readBytes(1);
		
		fseek($this->file, $offsetO[1]);
		$tableO = $this->_readBytes(2 * $count);
		fseek($this->file, $offsetT[1]);
		$tableT = $this->_readBytes(2 * $count);
		
		for ($i = 0; $i < $count; $i++)
		{
			if ($tableO[$i * 2 + 1] > 0)
			{
				fseek($this->file, $tableO[$i * 2 + 2]);
				$O = fread($this->file, $tableO[$i * 2 + 1]);
			}
			
			if ($tableT[$i * 2 + 1] > 0)
			{
				fseek($this->file, $tableT[$i * 2 + 2]);
				$this->strings[$O] = fread($this->file, $tableT[$i * 2 + 1]);
			}
		}
		
		fclose($this->file);
	}
}

?>