<?php
/*
 * Copyright 2007-2011 Charles du Jeu <contact (at) cdujeu.me>, Cyril Russo
 * This file is part of AjaXplorer.
 *
 * AjaXplorer is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * AjaXplorer 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with AjaXplorer.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The latest code can be found at <http://www.ajaxplorer.info/>.
 */
defined('AJXP_EXEC') or die( 'Access not allowed');
/**
 * @package info.ajaxplorer.core
 */
/**
 * Static utilitaries to encode/decode charset to/from utf8
 */
class SystemTextEncoding
{
    /**
     * Change the charset of a string from input to output
     * @static
     * @param string $inputCharset
     * @param string $outputCharset
     * @param string $text
     * @return string
     */
	static function changeCharset($inputCharset, $outputCharset, $text)
	{
	    if ($inputCharset == $outputCharset) return $text;
		// Due to iconv bug when dealing with text with non ASCII encoding for last char, we use this workaround http://fr.php.net/manual/fr/function.iconv.php#81494
		if(function_exists("iconv"))
		{
		    
			return iconv($inputCharset, $outputCharset, $text);
		}else
		{
			$content = @htmlentities($text, ENT_QUOTES, $inputCharset);  
			return @html_entity_decode($content, ENT_QUOTES , $outputCharset);
		}
	}

    static $currentCharsetValue;
	/**
     * Detect the current charset from the current locale
     * @static
     * @param string $locale
     * @return string
     */
	static function parseCharset($locale)
	{
		$test = explode("@", $locale);
		$locale = $test[0];		
		$encoding = substr(strrchr($locale, "."), 1);
		if (is_numeric($encoding))
		{
		    if (substr($encoding, 0, 2) == "12") // CP12xx are changed to Windows-12xx to allow PHP4 conversion
  			    $encoding = "windows-".$encoding;
  			else $encoding = "CP".$encoding; // In other cases, PHP4 won't work anyway, so use CPxxxx encoding (that iconv supports)
		} else if ($locale == "C")
		{   // Locale not set correctly, most probable error cause is /etc/init.d/apache having "LANG=C" defined
			// In any case, "C" is ASCII-7 bit so it's safe to use the extra bit as if it was UTF-8 
			$encoding = "UTF-8";
		}
		if (!strlen($encoding)) $encoding = "UTF-8";
		return $encoding;
	}
    /**
     * Try to detect the current encoding (cached in session)
     * @static
     * @return string
     */
	static function getEncoding(){
	       global $_SESSION;
	       // Check if the session get an assigned charset encoding (it's the case for remote SSH for example)
	       if (isset($_SESSION["AJXP_CHARSET"]) && strlen($_SESSION["AJXP_CHARSET"])) return $_SESSION["AJXP_CHARSET"];
	       // Get the current locale (expecting the filesystem is in the same locale, as the standard says)
           if(self::$currentCharsetValue == null){
               self::$currentCharsetValue = self::parseCharset(setlocale(LC_CTYPE, 0));
           }
	       return self::$currentCharsetValue;
	}
	/**
     * Decode a string from UTF8 to current Charset
     * @static
     * @param string $filesystemElement
     * @param bool $test Try to detect if it's really utf8 or not
     * @return string
     */
	static function fromUTF8($filesystemElement, $test = false){
		if($test && !SystemTextEncoding::isUtf8($filesystemElement)){
			return $filesystemElement;
		}
		$enc = SystemTextEncoding::getEncoding();
	    return SystemTextEncoding::changeCharset("UTF-8", $enc, $filesystemElement);
	}
  
	/**
     * This function is used when the server's PHP configuration is using magic quote
     * @param string $text
     * @return void
     */
    static function magicDequote($text)
    {
	    // If the PHP server enables magic quotes, remove them
	    if (function_exists('get_magic_quotes_gpc') && get_magic_quotes_gpc())
	        return stripslashes($text);
	    return $text;  
    }

    /**
     * Successive call of magicDequote and fromUTF8
     * @static
     * @param string $filesystemElement
     * @return string
     */
    static function fromPostedFileName($filesystemElement)
    {
	    return SystemTextEncoding::fromUTF8(SystemTextEncoding::magicDequote($filesystemElement));
	}
	/**
     * Transform a string from current charset to utf8
     * @static
     * @param string $filesystemElement
     * @param bool $test Test if it's already UTF8 or not, to avoid double-encoding
     * @return string
     */
	static function toUTF8($filesystemElement, $test = true){
		if($test && SystemTextEncoding::isUtf8($filesystemElement)){
			return $filesystemElement;
		}
		$enc = SystemTextEncoding::getEncoding();
		return SystemTextEncoding::changeCharset($enc, "UTF-8", $filesystemElement);
	}
	/**
     * Test if a string seem to be already UTF8-encoded
     * @static
     * @param string $string
     * @return bool
     */
	static function isUtf8($string){
    	return preg_match('%^(?: 
	      [\x09\x0A\x0D\x20-\x7E]            # ASCII 
	    | [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte 
	    | \xE0[\xA0-\xBF][\x80-\xBF]         # excluding overlongs 
	    | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte 
	    | \xED[\x80-\x9F][\x80-\xBF]         # excluding surrogates 
	    | \xF0[\x90-\xBF][\x80-\xBF]{2}      # planes 1-3 
	    | [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15 
	    | \xF4[\x80-\x8F][\x80-\xBF]{2}      # plane 16 
			)*$%xs', $string);
    }
}

?>
