PHP realpath() alternative (free software)

resolve_path.php

<?php
/**
 * Effectively resolve '..' characters in a file path
 * @license GPLv3
 */
function resolvePath($path)
{
    $resolvedPath = array();
    // do some normalization
    $path        = str_replace('//', '/', $path);
    $path_pieces = explode('/', $path);
    foreach ($path_pieces as $piece) {
        if ($piece == '.') {
            continue;
        }
        if ($piece == '..') {
            if (!is_array($resolvedPath)) {
                error_log("ERROR: Resolved path not an array");
                return "";
            }
            array_pop($resolvedPath);
            continue;
        }
        array_push($resolvedPath, $piece);
    }
    $resolvedPath = implode('/', $resolvedPath);
    return $resolvedPath;
}
?>