SOUNDEX 2 FRANCAIS

<?php
/**
* CLASS soundex2
* soundex2 French version
* based on the algorithm described here : http://sqlpro.developpez.com/cours/soundex/ by Frédéric BROUARD
*
* author Johan Barbier <barbier_johan@hotmail.com>
*/
class soundex2 {

	/**
	* public sString
	* main string we work on
	*/
	public $sString = '';

	/**
	* vowels replacement array
	*/
	private $aReplaceVoy1 = array (
		'E' => 'A',
		'I' => 'A',
		'O' => 'A',
		'U' => 'A'
	);

	/**
	* consonnants replacement array
	*/
	private $aReplaceGrp1 = array (
		'GUI' => 'KI',
		'GUE' => 'KE',
		'GA' => 'KA',
		'GO' => 'KO',
		'GU' => 'K',
		'CA' => 'KA',
		'CO' => 'KO',
		'CU' => 'KU',
		'Q' => 'K',
		'CC' => 'K',
		'CK' => 'K'
		);

	/**
	* other replacement array
	*/
	private $aReplaceGrp2 = array (
		'ASA' => 'AZA',
		'KN' => 'NN',
		'PF' => 'FF',
		'PH' => 'FF',
            	'SCH' => 'SSS'
		);

	/**
	* endings replacement array
	*/
	private $aEnd = array (
		'A',
		'T',
		'D',
		'S'
		);

	/**
	* public function build
	* core function of the class, go through the whole process
	* @Param string sString : the string we want to check
	*/
	public function build ($sString) {
		/**
		* let's check it's a real string...
		*/
		if (is_string ($sString)) {
			$this -> sString = $sString;
		}
		/**
		* remove starting and ending spaces
		*/
		$this -> sString = trim ($this -> sString);
		/**
		* remove special french characters
		*/
		$this -> trimAccent ();
		/**
		* string to upper case
		*/
		$this -> sString = strtoupper ($this -> sString );
		/**
		* let's remove every space in the string
		*/
		$this -> sString = str_replace (' ', '', $this -> sString);
		/**
		* let's remove every '-' in the string
		*/
		$this -> sString = str_replace ('-', '', $this -> sString);
		/**
		* let's process through the first replacement array
		*/
		$this -> arrReplace ($this -> aReplaceGrp1);
		/**
		* let's process through th vowels replacement
		*/
		$sChar = substr ($this -> sString, 0, 1);
		$this -> sString = substr ($this -> sString, 1, strlen ($this -> sString) - 1);
		$this -> arrReplace ($this -> aReplaceVoy1);
		$this -> sString = $sChar.$this -> sString;
		/**
		* let's process through the second replacement array
		*/
		$this -> arrReplace ($this -> aReplaceGrp2, true);
		/**
		* let's remove every 'H' but those prededed by a 'C' or an 'S'
		*/
		$this -> sString = preg_replace ('/(?<![CS])H/', '', $this -> sString);
		/**
		* let's remove every 'Y' but those preceded by an 'A'
		*/
		$this -> sString = preg_replace ('/(?<!A)Y/', '', $this -> sString);
		/**
		* remove endings in aEnd
		*/
		$length = strlen ($this -> sString) - 1;
		if (in_array ($this -> sString{$length}, $this -> aEnd)) {
			$this -> sString = substr ($this -> sString, 0, $length);
		}
		/**
		* let's remove every 'A', but the one at the beginning of the string, if any.
		*/
		$sChar = '';
		if ($this -> sString{0} === 'A') {
			$sChar = 'A';
		}
		$this -> sString = str_replace ('A', '', $this -> sString);
		$this -> sString = $sChar.$this -> sString;
		/**
		* let's have only 1 occurence of each letter
		*/
		$this -> sString = preg_replace( '`(.)\1`', '$1', $this -> sString );
		/**
		* let's have the final code : a 4 letters string
		*/
		$this -> getFinal ();
	}

	/**
	* private function getFinal
	* gets the first 4 letters, pads the string with white space if the string length < 4
	*/
	private function getFinal () {
		if (strlen ($this -> sString) < 4) {
			$this -> sString = str_pad ($this -> sString, 4, ' ', STR_PAD_RIGHT);
		} else {
			$this -> sString = substr ($this -> sString, 0, 4);
		}
	}

	/**
	* private function trimAccent
	* remove every special French letters
	*/
	private function trimAccent () {
	   $this -> sString = htmlentities(strtolower($this -> sString ));
	   $this -> sString = preg_replace("/&(.)(acute|cedil|circ|ring|tilde|uml|grave);/", "$1", $this -> sString );
	   $this -> sString = preg_replace("/([^a-z0-9]+)/", "-", html_entity_decode($this -> sString ));
	   $this -> sString = trim($this -> sString , "-");
	}

	/**
	* private function arrReplace
	* replacement method, given an array
	* @Param array tab : the replacement array to be used
	* @Param bool pref : if false, just replace keys by values; if true, do the same but only with prefix
	*/
	private function arrReplace (array $tab, $pref = false) {
		$fromRep = array_keys ($tab);
		$toRep = array_values ($tab);
		if (false === $pref) {
			$this -> sString = str_replace ($fromRep, $toRep, $this -> sString);
		} else {
			foreach ($fromRep as $clef => $val) {
				$length = strlen ($val);
				if (substr ($this -> sString, 0, $length) === $val) {
					$this -> sString = substr_replace ($this -> sString, $toRep[$clef], 0, $length);
				}
			}
		}
	}

}
?>