How to validate tin and cst using PHP?

PHP Snippet 1:

function validateFieldByRegex($regex , $string)
{
    if ( !preg_match($regex, $string) ) {
        echo 'incorrect string';
    } else {
        echo 'correct string';
    }
}

validateFieldByRegex('/^[1-9]([0-9]{1,10}$)/', '33392964390');
validateFieldByRegex('/^[1-9]([0-9]{1,6}$)/', '1280154');

PHP Snippet 2:

^(3[0-5]|[012][0-9]|[1-9])\d{9}$