autoload.php

<?php

class Autoloader {
    static function register($namespace, $classpaths) {
        if (!is_array($classpaths)) {
            $classpaths = array($classpaths);
        }
        spl_autoload_register(function ($classname) use ($namespace, $classpaths) {
            // Check if the namespace matches the class we are looking for
            if (preg_match("#^".preg_quote($namespace)."#", $classname)) {
                // Remove the $namespace from the file path since it's psr4
                $classname = str_replace($namespace, "", $classname);
                $filename = preg_replace("#\\\\#", "/", $classname).".php";
                foreach ($classpaths as $classpath) {
                    $fullpath = __DIR__."/".$classpath."/$filename";
                    if (file_exists($fullpath)) {
                        include_once $fullpath;
                    }
                }
            }
        });
    }
}