php psr-4 autoloader

autoload.php

<?php

declare(strict_types=1);

$configuration = json_decode(file_get_contents(__DIR__ . '/../project.json'), true);
$namespaces = $configuration['autoload']['psr-4'];

function fqcnToPath(string $fqcn, string $prefix)
{
    $relativeClass = ltrim($fqcn, $prefix);
    return str_replace('\\', '/', $relativeClass) . '.php';
}

spl_autoload_register(function (string $class) use ($namespaces) {
    $prefix = strtok($class, '\\') . '\\';

    if (!array_key_exists($prefix, $namespaces)) {
        return;
    }

    $baseDirectory = $namespaces[$prefix];
    $path = fqcnToPath($class, $prefix);

    require $baseDirectory . '/' . $path;
});