Autoloader.php

<?php
/*
    This file is part of Plop, a simple logging library for PHP.

    Copyright © 2010-2014 François Poirotte

    Plop is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Plop is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Plop.  If not, see <http://www.gnu.org/licenses/>.
*/

namespace Plop;

class Autoloader
{
    protected static $instance;

    protected function __construct()
    {
    }

    public function __clone()
    {
        throw new \Exception('Cloning this class is forbidden');
    }

    public static function register()
    {
        if (self::$instance === null) {
            self::$instance = new static();
            spl_autoload_register(array(self::$instance, 'load'));
        }
    }

    public function load($class)
    {
        $class = ltrim($class, '\\');
        if (strncasecmp($class, 'Plop\\', 4)) {
            return false;
        }

        if (strpos($class, '://') !== false) {
            throw new \Exception('Possible exploitation attempt detected');
        }

        $class = str_replace(array('_', '\\'), DIRECTORY_SEPARATOR, substr($class, 5));
        require_once(__DIR__ . DIRECTORY_SEPARATOR . $class . '.php');
        return true;
    }
}