Simple PSR-4 autoloader

autoload.php

<?php

/**
 * Very simple PSR-4 compatible autoloader
 */
function __autoload($className)
{
    /**
     * Specify Directories
     *
     * Example:
     *
     *   'Acme\\Foo\\' => 'src/acme/foo/src/'
     *
     * would look for the class `Acme\Foo\Bar` in the file:
     *
     *   src/acme/foo/src/Bar.php
     */
    $directories = array(
        'CodedMonkey\\Sample\\'  => 'src/sample/src/',
    );
    
    foreach ($directories as $namespace => $directory) {
        // Check if the called class is part of this namespace
        if (strpos($className, $namespace) !== 0) {
            continue;
        }
        
        // Strip the namespace from the class name (Enables PSR-4)
        $className = str_replace($namespace, '', $className);
        
        // Build the path to the supposed class file
        $className = str_replace('\\', '/', $className);
        $filename = rtrim($directory, '/') . '/' . $className . '.php';
        
        if (!file_exists($filename)) {
            continue;
        }
        
        include_once $filename;
    }
}