note 119670 added to function.random-int
| From: | srotondo90atgmailcom | Date: | Sat, 30 Jul 2016 13:11:25 +0000 |
| Subject: | note 119670 added to function.random-int | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-206132@lists.php.net to get a copy of this message | ||
Here is a simple backporting function, it works for PHP >= 5.1
<?php
if (!function_exists('random_int')) {
function random_int($min, $max) {
if (!function_exists('mcrypt_create_iv')) {
trigger_error(
'mcrypt must be loaded for random_int to work',
E_USER_WARNING
);
return null;
}
if (!is_int($min) || !is_int($max)) {
trigger_error('$min and $max must be integer values', E_USER_NOTICE);
$min = (int)$min;
$max = (int)$max;
}
if ($min > $max) {
trigger_error('$max can\'t be lesser than $min', E_USER_WARNING);
return null;
}
$range = $counter = $max - $min;
$bits = 1;
while ($counter >>= 1) {
++$bits;
}
$bytes = (int)max(ceil($bits/8), 1);
$bitmask = pow(2, $bits) - 1;
if ($bitmask >= PHP_INT_MAX) {
$bitmask = PHP_INT_MAX;
}
do {
$result = hexdec(
bin2hex(
mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
)
) & $bitmask;
} while ($result > $range);
return $result + $min;
}
}
?>
Randomness test
<?php
$max = 100; // number of random values
$test = 1000000;
$array = array_fill(0, $max, 0);
for ($i = 0; $i < $test; ++$i) {
++$array[random_int(0, $max-1)];
}
function arrayFormatResult(&$item) {
global $test, $max; // try to avoid this nowdays ;)
$perc = ($item/($test/$max))-1;
$item .= ' '. number_format($perc, 4, '.', '') .'%';
}
array_walk($array, 'arrayFormatResult');
print_r($array);
?>
----
Server IP: 72.52.91.14
Probable Submitter: 87.30.188.45
----
Manual Page -- http://php.net/manual/en/function.random-int.php
Edit -- https://master.php.net/note/edit/119670
Del: integrated -- https://master.php.net/note/delete/119670/integrated
Del: useless -- https://master.php.net/note/delete/119670/useless
Del: bad code -- https://master.php.net/note/delete/119670/bad+code
Del: spam -- https://master.php.net/note/delete/119670/spam
Del: non-english -- https://master.php.net/note/delete/119670/non-english
Del: in docs -- https://master.php.net/note/delete/119670/in+docs
Del: other reasons-- https://master.php.net/note/delete/119670
Reject -- https://master.php.net/note/reject/119670
Search -- https://master.php.net/manage/user-notes.php