Greek toUppercase converter

grstroupper.php

<?php

/**
 * CodeIgniter String Helpers
 *
 * @package	OpenReceptor CMS
 * @subpackage	Helpers
 * @category	Helpers
 * @author	Dimitris Krestos
 * @link	http://vdw.staytuned.gr
 */
/**
 * Greek string to uppercase
 * Correctly converts greek letters to uppercase.
 * @access	public
 * @param	string
 * @return	string
 */
if ( ! function_exists('grstrtoupper'))
{
	function grstrtoupper($string) {
		$latin_check = '/[\x{0030}-\x{007f}]/u';
		if (preg_match($latin_check, $string))
		{
			$string = strtoupper($string);
		}
		$letters = array('α', 'β', 'γ', 'δ', 'ε', 'ζ', 'η', 'θ', 'ι', 'κ', 'λ', 'μ', 'ν', 'ξ', 'ο', 'π', 'ρ', 'σ', 'τ', 'υ', 'φ', 'χ', 'ψ', 'ω');
		$letters_accent = array('ά', 'έ', 'ή', 'ί', 'ό', 'ύ', 'ώ');
		$letters_upper_accent	= array('Ά', 'Έ', 'Ή', 'Ί', 'Ό', 'Ύ', 'Ώ');
		$letters_upper_solvents	= array('ϊ', 'ϋ');
		$letters_other = array('ς');
		$letters_to_uppercase	= array('Α', 'Β', 'Γ', 'Δ', 'Ε', 'Ζ', 'Η', 'Θ', 'Ι', 'Κ', 'Λ', 'Μ', 'Ν', 'Ξ', 'Ο', 'Π', 'Ρ', 'Σ', 'Τ', 'Υ', 'Φ', 'Χ', 'Ψ', 'Ω');
		$letters_accent_to_uppercase = array('Α', 'Ε', 'Η', 'Ι', 'Ο', 'Υ', 'Ω');
		$letters_upper_accent_to_uppercase = array('Α', 'Ε', 'Η', 'Ι', 'Ο', 'Υ', 'Ω');
		$letters_upper_solvents_to_uppercase = array('Ι', 'Υ');
		$letters_other_to_uppercase = array('Σ');
		$lowercase = array_merge($letters, $letters_accent, $letters_upper_accent, $letters_upper_solvents, $letters_other);
		$uppercase = array_merge($letters_to_uppercase, $letters_accent_to_uppercase, $letters_upper_accent_to_uppercase, $letters_upper_solvents_to_uppercase, $letters_other_to_uppercase);
		$uppecase_string = str_replace($lowercase, $uppercase, $string);
		
		return $uppecase_string;
	}
}