http://stackoverflow.com/questions/959957/php-short-hash-like-url-shortening-websites

0-BaseIntEncoder.php

<?php

class BaseIntEncoder {

    //const $codeset = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    //readable character set excluded (0,O,1,l)
    const codeset = "23456789abcdefghijkmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";

    static function encode($n){
        $base = strlen(self::codeset);
        $converted = '';

        while ($n > 0) {
            $converted = substr(self::codeset, bcmod($n,$base), 1) . $converted;
            $n = self::bcFloor(bcdiv($n, $base));
        }

        return $converted ;
    }

    static function decode($code){
        $base = strlen(self::codeset);
        $c = '0';
        for ($i = strlen($code); $i; $i--) {
            $c = bcadd($c,bcmul(strpos(self::codeset, substr($code, (-1 * ( $i - strlen($code) )),1))
                    ,bcpow($base,$i-1)));
        }

        return bcmul($c, 1, 0);
    }

    static private function bcFloor($x)
    {
        return bcmul($x, '1', 0);
    }

    static private function bcCeil($x)
    {
        $floor = bcFloor($x);
        return bcadd($floor, ceil(bcsub($x, $floor)));
    }

    static private function bcRound($x)
    {
        $floor = bcFloor($x);
        return bcadd($floor, round(bcsub($x, $floor)));
    }
}

1-result.php

<?php

BaseIntEncoder::encode('1122344523');//result:3IcjVE
BaseIntEncoder::decode('3IcjVE');//result:1122344523