Base58 Trait (like Base62) Encode/Decode

gistfile1.aw

//
// Base58 Encode/Decode Trait for PHP
// ==================================
// Base58 is like Base62 except that it removes certain problematic characters such as 0, O, I, and l.
// This is great if you need the encoded output to be easily human-readable. Like short URLs...
//

trait Base58 {
    private $alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';

    function base63_encode($num) {
        $base_count = strlen($this->alphabet);
        $encoded = '';

        while ($num >= $base_count) {
            $div = $num / $base_count;
            $mod = ($num - ($base_count * intval($div)));
            $encoded = $this->alphabet[$mod] . $encoded;
            $num = intval($div);
        }

        if ($num) $encoded = $this->alphabet[$num] . $encoded;

        return $encoded;
    }

    function base63_decode($num) {
        $decoded = 0;
        $multi = 1;

        while (strlen($num) > 0) {
            $digit = $num[strlen($num) - 1];
            $decoded += $multi * strpos($this->alphabet, $digit);
            $multi = $multi * strlen($this->alphabet);
            $num = substr($num, 0, -1);
        }

        return $decoded;
    }
}