<?php

/*
 * This file is part of the Predis package.
 *
 * (c) Daniele Alessandri <suppakilla@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Predis;

/**
 * Implements a lightweight PSR-0 compliant autoloader.
 *
 * @author Eric Naeseth <eric@thumbtack.com>
 */
class Autoloader
{
    private $baseDir;
    private $prefix;

    /**
     * @param string $baseDirectory Base directory where the source files are located.
     */
    public function __construct($baseDirectory = null)
    {
        $this->baseDir = $baseDirectory ?: dirname(__FILE__);
        $this->prefix = __NAMESPACE__ . '\\';
    }

    /**
     * Registers the autoloader class with the PHP SPL autoloader.
     */
    public static function register()
    {
        spl_autoload_register(array(new self, 'autoload'));
    }

    /**
     * Loads a class from a file using its fully qualified name.
     *
     * @param string $className Fully qualified name of a class.
     */
    public function autoload($className)
    {
        if (0 !== strpos($className, $this->prefix)) {
            return;
        }

        $relativeClassName = substr($className, strlen($this->prefix));
        $classNameParts = explode('\\', $relativeClassName);

        $path = $this->baseDir .
            DIRECTORY_SEPARATOR .
            implode(DIRECTORY_SEPARATOR, $classNameParts) .
            '.php';

        require_once $path;
    }
}