I have a problem with my autoloader:

public function loadClass($className) {
    $file = str_replace(array('_', '\\'), '/', $className) . '.php';
    include_once $file;
}

As you can see, it's quite simple. I just deduce the filename of the class and try to include it. I have a problem though; I get an exception when trying to load a non-existing class (because I have an error handler which throws exceptions). This is inconvenient, because it's also fired when you use class_exists() on a non-existing class. You don't want an exception there, just a "false" returned.

I fixed this earlier by putting an @ before the include (supressing all errors). The big drawback with this, though, is that any parser/compiler errors (that are fatal) in this include won't show up (not even in the logs), resulting in a hard to find bug.

What would be the best way to solve both problems at once? The easiest way would be to include something like this in the autoloader (pseudocode):

foreach (path in the include_path) {
    if (is_readable(the path + the class name)) readable = true;
}
if (!readable) return;

But I worry about the performance there. Would it hurt a lot?

(Solved) Made it like this:

public function loadClass($className) {

	$file = str_replace(array('_', '\\'), '/', $className) . '.php';	
	$paths = explode(PATH_SEPARATOR, get_include_path());
	foreach ($paths as $path) {
		if (is_readable($path . '/' . $file)) {
                        include_once $file;
                        return;
                    }
	}

}