Credit card validation script in PHP

cc-validate.php

<?php 
function CCValidate($type, $cNum) {
    switch ($type) {
    case "American":
        $pattern = "/^([34|37]{2})([0-9]{13})$/";//American Express
		return (preg_match($pattern,$cNum)) ? true : false; 
        break;
    case "Dinners":
        $pattern = "/^([30|36|38]{2})([0-9]{12})$/";//Diner's Club
		return (preg_match($pattern,$cNum)) ? true : false;
        break;
    case "Discover":
        $pattern = "/^([6011]{4})([0-9]{12})$/";//Discover Card
		return (preg_match($pattern,$cNum)) ? true : false;
        break;
    case "Master":
        $pattern = "/^([51|52|53|54|55]{2})([0-9]{14})$/";//Mastercard
		return (preg_match($pattern,$cNum)) ? true : false;
        break;
    case "Visa":
        $pattern = "/^([4]{1})([0-9]{12,15})$/";//Visa
		return (preg_match($pattern,$cNum)) ? true : false; 
        break;               
   }
} 
?>