psr4

 * An example of a project-specific implementation.
 *
 * After registering this autoload function with SPL, the following line
 * would cause the function to attempt to load the FooBarBazQux class
 * from /path/to/project/src/Baz/Qux.php:
 *
 *      new FooBarBazQux;
 *
 * @param string $class The fully-qualified class name.
 * @return void
 */
 spl_autoload_register(function ($class) {

    $prefix = 'Vendor';
    $baseDir = __DIR__.'/';

    $len = strlen($prefix);
    if (! strncmp($prefix, $class, $len)) {
        return ;
    }

    $file = $baseDir .str_replace('\', '/', $class).'.php';
    if (file_exists($file)) {
        require $file;
        // require_once($file);
    }
 });

 $a = new VendorFoodFood();

class 
{
    public $prefixesMap = array();

    public function register ()
    {
        spl_autoload_register($this, 'loadClass');
    }

    public function addNamespace ($prefix, $base_dir, $prepend = false)
    {
        $prefix = trim($prefix, '\').'\';

        $base_dir = rtrim($base_dir, DIRECTORY_SEPARATOR).'/';

        // initialize the namespace prefix array
        if (isset($this->prefixesMap[$prefix]) === false) {
            $this->prefixesMap[$prefix] = array();
        }

        // retain the base directory for the namespace prefix
        if ($prepend) {
            array_unshift($this->prefixesMap[$prefix], $base_dir);
        } else {
            array_push($this->prefixesMap[$prefix], $base_dir);
        }

    } 

    public function loadClass ($class)
    {
        $prefix = $class;   
        while ( false !== $pos = strrpos($prefix, '\')) {
            $prefix = substr($class, 0, $pos + 1);
            $relative_class = substr($class, $pos + 1);

            $mapped_file = $this->loadMapFile($prefix, $relative_class);
            if ($mapped_file) {
                return $mapped_file;
            }

            $prefix = rtrim($prefix, '\');
        }

        return false;
    }

    protected function loadMapFile ($prefix, $relative_class)
    {
   
        if (isset($this->prefixesMap[$prefix]) === false) {
            return false;
        }

        foreach ($this->prefixesMap[$prefix] as $base_dir) {
            $file = $base_dir.$relative_class.'.php';
            if ($this->include($file)) {
                return $file;
            }
        }

        return ;
    }

    protected function include ($file)
    {
        if (file_exists($file)) {
            require $file;
            return true;
        }
        return false;
    }
}