Password generator PHP

passgen.php

<?php

$length = 32;

if ($argc > 1) {
  $length = intval($argv[1]);
}

$token = '';
$rand_length = 4;
if ($argc > 2) {
    $rand_length = 3;
}

for ($i=0; $i < $length; $i++) {

    $type = mt_rand(1, $rand_length);

    switch($type) {
    case '1':
        // cifre 0-9
        $rand = mt_rand(48, 57);
        $token .= chr($rand);
        break;
    case '2':
        // lettere A-Z
        $rand = mt_rand(65, 90);
        $token .= chr($rand);
        break;
    case '3':
        // lettere a-z
        $rand = mt_rand(97, 122);
        $token .= chr($rand);
        break;
    case '4':
        // caratteri random
        $chars = array('!','%','&','=','?',']','[');
        $token .= $chars[mt_rand(0, count($chars) - 1)];
        break;
    }
}

echo $token . "\n";