autoload.php

<?php

/** Helper for loading classes
 * Applicable only when Composer is not used!
 * @author Jakub Jasiulewicz <jjasiulewicz@monetivo.com>
 * @param $dir
 * @throws Exception
 */
function loadWithoutComposer($dir)
{
    // load and parse composer.json file for PSR-4 namespaces
    $file = $dir . DIRECTORY_SEPARATOR . 'composer.json';
    if (!file_exists($file) || !is_readable($file)) {
        throw new Exception('composer.json file for this package is not accessible.');
    }

    $composer = json_decode(file_get_contents($file), 1);
    if (json_last_error() !== JSON_ERROR_NONE || !isset($composer['autoload']['psr-4'])) {
        throw new Exception('composer.json file for this package is corrupted. Please re-download the library and try again.');
    }
    $namespaces = $composer['autoload']['psr-4'];

    // load desired classes
    foreach ($namespaces as $namespace => $classpath) {
        spl_autoload_register(function ($classname) use ($namespace, $classpath, $dir) {
            if (preg_match('#^' . preg_quote($namespace) . '#', $classname)) {
                $classname = str_replace($namespace, '', $classname);
                $filename = preg_replace("#\\\\#", '/', $classname) . '.php';
                include_once sprintf('%s/%s/%s', $dir, $classpath, $filename);
            }
        }, true, true);
    }
}

loadWithoutComposer(__DIR__);