Strong Password Generator

generateStrongPassword.php

<?php
/**
 * Code Snippet for Strong Password Generation
 *
 * @param int $length
 * @param bool|false $add_dashes
 * @param string $available_sets
 * @return string
 */
function generateStrongPassword($length = 9, $add_dashes = false, $available_sets = 'luds')
{
    $sets = array();
    if(strpos($available_sets, 'l') !== false)
        $sets[] = 'abcdefghjkmnpqrstuvwxyz';
    if(strpos($available_sets, 'u') !== false)
        $sets[] = 'ABCDEFGHJKMNPQRSTUVWXYZ';
    if(strpos($available_sets, 'd') !== false)
        $sets[] = '23456789';
    if(strpos($available_sets, 's') !== false)
        $sets[] = '!@#$%&*?';
    $all = '';
    $password = '';
    foreach($sets as $set)
    {
        $password .= $set[array_rand(str_split($set))];
        $all .= $set;
    }
    $all = str_split($all);
    for($i = 0; $i < $length - count($sets); $i++)
        $password .= $all[array_rand($all)];
    $password = str_shuffle($password);
    if(!$add_dashes)
        return $password;
    $dash_len = floor(sqrt($length));
    $dash_str = '';
    while(strlen($password) > $dash_len)
    {
        $dash_str .= substr($password, 0, $dash_len) . '-';
        $password = substr($password, $dash_len);
    }
    $dash_str .= $password;
    return $dash_str;
}