Method filter

/**
 * Method to filter a field value.
 *
 * @param   \SimpleXMLElement  $element  The SimpleXMLElement object representing the `<field>` tag for the form field object.
 * @param   mixed              $value    The form field value to validate.
 * @param   string             $group    The field name group control value. This acts as an array container for the field.
 *                                       For example if the field has name="foo" and the group value is set to "bar" then the
 *                                       full field name would end up being "bar[foo]".
 * @param   Registry           $input    An optional Registry object with the entire data set to validate against the entire form.
 * @param   Form               $form     The form object for which the field is being tested.
 *
 * @return  mixed   The filtered value.
 *
 * @since   4.0.0
 */
public function filter(\SimpleXMLElement $element, $value, $group = null, Registry $input = null, Form $form = null)
{
    $value = trim($value);
    // Does it match the NANP pattern?
    if (preg_match('/^(?:\\+?1[-. ]?)?\\(?([2-9][0-8][0-9])\\)?[-. ]?([2-9][0-9]{2})[-. ]?([0-9]{4})$/', $value) == 1) {
        $number = (string) preg_replace('/[^\\d]/', '', $value);
        if (substr($number, 0, 1) === '1') {
            $number = substr($number, 1);
        }
        if (substr($number, 0, 2) === '+1') {
            $number = substr($number, 2);
        }
        $result = '1.' . $number;
    } elseif (preg_match('/^\\+(?:[0-9] ?){6,14}[0-9]$/', $value) == 1) {
        $countrycode = substr($value, 0, strpos($value, ' '));
        $countrycode = (string) preg_replace('/[^\\d]/', '', $countrycode);
        $number = strstr($value, ' ');
        $number = (string) preg_replace('/[^\\d]/', '', $number);
        $result = $countrycode . '.' . $number;
    } elseif (preg_match('/^\\+[0-9]{1,3}\\.[0-9]{4,14}(?:x.+)?$/', $value) == 1) {
        if (strstr($value, 'x')) {
            $xpos = strpos($value, 'x');
            $value = substr($value, 0, $xpos);
        }
        $result = str_replace('+', '', $value);
    } elseif (preg_match('/[0-9]{1,3}\\.[0-9]{4,14}$/', $value) == 1) {
        $result = $value;
    } else {
        $value = (string) preg_replace('/[^\\d]/', '', $value);
        if ($value != null && \strlen($value) <= 15) {
            $length = \strlen($value);
            // If it is fewer than 13 digits assume it is a local number
            if ($length <= 12) {
                $result = '.' . $value;
            } else {
                // If it has 13 or more digits let's make a country code.
                $cclen = $length - 12;
                $result = substr($value, 0, $cclen) . '.' . substr($value, $cclen);
            }
        } else {
            $result = '';
        }
    }
    return $result;
}