<?php

function validateUsername($s)
{
	if (!isset($s) || trim($s)=='') return false;
	if (preg_match("/^[0-9a-zA-Z_]{3,}$/", $s) === 0) return false;
	return true;
}

function validateWithPattern($s, $pattern)
{
	if (!isset($s) || trim($s)=='') return false;
	if (preg_match("/^[$pattern]{3,}$/", $s) === 0) return false;
	return true;
}