A PHP class to generate Unix symbolic permission notation (eg "-rw-r--r--") from lstat()/fileperms()

perms.php

<?php

class Perms {
    /** @var int */
    private $mode;

    /** @param string $path */
    function __construct($path) {
        $this->mode = fileperms($path);
    }

    function symbolic() {
        static $types = array(
            015 => 'D',
            014 => 's',
            012 => 'l',
            010 => '-',
            006 => 'b',
            004 => 'd',
            002 => 'c',
            001 => 'p',
        );

        return
            $types[$this->bits(12, 4)] .
            $this->perms(2, 'Ss') .
            $this->perms(1, 'Ss') .
            $this->perms(0, 'Tt');
    }

    private function perms($i, $s) {
        $r = '-r';
        $w = '-w';
        $x = $this->bits($i + 9) ? $s : '-x';

        return
            $r[$this->bits($i * 3 + 2)] .
            $w[$this->bits($i * 3 + 1)] .
            $x[$this->bits($i * 3 + 0)];
    }

    private function bits($i, $n = 1) {
        return ($this->mode >> $i) & ~(~0 << $n);
    }
}