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<?php
function user_exists($username) {
$username = sanitize($username);
return (mysql_result(mysql_query("SELECT COUNT(`USER_id`) FROM `users` WHERE `username`='$username'"), 0) == 1) ? true : false;
 
}
 
function user_active($username) {
$username = sanitize($username);
return (mysql_result(mysql_query("SELECT COUNT(`USER_id`) FROM `users` WHERE `username`='$username' AND `active` = 1"), 0) == 1) ? true : false;
}
function user_id_from_username($username)	{
	$username = sanitize($username);
	return mysql_result(mysql_query("SELECT `USER_id` FROM `users` WHERE `username`='$username'"), 0, 'USER_id');
}
function login($username, $password)	{
	$USER_id = user_id_from_username($username);
 
	$username = sanitize($username);
	$password = md5($password);
 
	return (mysql_result(mysql_query("SELECT COUNT (`USER_id`) FROM `users` WHERE `username`='$username' AND `password`='$password'"), 0) == 1) ? $USER_id : false;
}
?>