Swift_CharacterStream_ArrayCharacterStream::_initializeMaps PHP Method

    private static function _initializeMaps()
    {
        if (!isset(self::$_charMap)) {
            self::$_charMap = array();
            for ($byte = 0; $byte < 256; ++$byte) {
                self::$_charMap[$byte] = chr($byte);
            }
            self::$_byteMap = array_flip(self::$_charMap);
        }
    }