A PSR-0 autoloader compatible

autoload.php

<?php

/**
 * Autoload function for PHP. (Compatible PSR-0)
 * Use automatic include base on directory
 */
function autoload($className)
{
    $className = ltrim($className, '\\');
    $fileName  = '';
    $namespace = '';
    if ($lastNsPos = strripos($className, '\\')) {
        $namespace = substr($className, 0, $lastNsPos);
        $className = substr($className, $lastNsPos + 1);
        $fileName  = str_replace('\\', DIRECTORY_SEPARATOR, $namespace) . DIRECTORY_SEPARATOR;
    }
    $fileName .= str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';

    require $fileName;
}

/**
 * Add a directory to include path for Autoload
 * @param string $path 
 */
function add_include_path ($path)
{
    foreach (func_get_args() AS $path)
    {
        if (!file_exists($path) OR (file_exists($path) && filetype($path) !== 'dir'))
        {
            trigger_error("Include path '{$path}' not exists", E_USER_WARNING);
            continue;
        }
        
        $paths = explode(PATH_SEPARATOR, get_include_path());
        
        if (array_search($path, $paths) === false)
            array_push($paths, $path);
        
        set_include_path(implode(PATH_SEPARATOR, $paths));
    }
}