realpath() without resolving symlinks?

Question

I already read about realpath(), but is there a function that I can pass a base directory and a filename that would give me the following result without resolvi

Answer 1

function normalize_path($path, $pwd = '/') {
        if (!isset($path[0]) || $path[0] !== '/') {
                $result = explode('/', getcwd());
        } else {
                $result = array('');
        }
        $parts = explode('/', $path);
        foreach($parts as $part) {
            if ($part === '' || $part == '.') {
                    continue;
            } if ($part == '..') {
                    array_pop($result);
            } else {
                    $result[] = $part;
            }
        }
        return implode('/', $result);
}

(The question was tagged PHP at the time I wrote this.)

Anyway, here is a regex version:

function normalize_path($path, $pwd = '/') {
        if (!isset($path[0]) || $path[0] !== '/') {
                $path = "$pwd/$path";
        }
        return preg_replace('~
                ^(?P>sdotdot)?(?:(?P>sdot)*/\.\.)*
                |(?(?:(?P>sdot)*/(?!\.\.)(?:[^/]+)(?P>sdotdot)?(?P>sdot)*/\.\.)+)
                |(?/\.?(?=/|$))+
        ~sx', '', $path);
}