1: <?php
 2: 
 3: /**
 4:  * This file is part of the Nette Framework (https://nette.org)
 5:  * Copyright (c) 2004 David Grudl (https://davidgrudl.com)
 6:  */
 7: 
 8: namespace Nette\Utils;
 9: 
10: use Nette;
11: 
12: 
13: /**
14:  * Secure random string generator.
15:  *
16:  * @author     David Grudl
17:  */
18: class Random
19: {
20: 
21:     /**
22:      * Generate random string.
23:      * @param  int
24:      * @param  string
25:      * @return string
26:      */
27:     public static function generate($length = 10, $charlist = '0-9a-z')
28:     {
29:         $charlist = count_chars(preg_replace_callback('#.-.#', function ($m) {
30:             return implode('', range($m[0][0], $m[0][2]));
31:         }, $charlist), 3);
32:         $chLen = strlen($charlist);
33: 
34:         if ($length < 1) {
35:             return ''; // mcrypt_create_iv does not support zero length
36:         } elseif ($chLen < 2) {
37:             return str_repeat($charlist, $length); // random_int does not support empty interval
38:         }
39: 
40:         $res = '';
41:         if (PHP_VERSION_ID >= 70000) {
42:             for ($i = 0; $i < $length; $i++) {
43:                 $res .= $charlist[random_int(0, $chLen - 1)];
44:             }
45:             return $res;
46:         }
47: 
48:         $windows = defined('PHP_WINDOWS_VERSION_BUILD');
49:         $bytes = '';
50:         if (function_exists('openssl_random_pseudo_bytes')
51:             && (PHP_VERSION_ID >= 50400 || !defined('PHP_WINDOWS_VERSION_BUILD')) // slow in PHP 5.3 & Windows
52:         ) {
53:             $bytes = openssl_random_pseudo_bytes($length, $secure);
54:             if (!$secure) {
55:                 $bytes = '';
56:             }
57:         }
58:         if (strlen($bytes) < $length && function_exists('mcrypt_create_iv') && (PHP_VERSION_ID >= 50307 || !$windows)) { // PHP bug #52523
59:             $bytes = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM);
60:         }
61:         if (strlen($bytes) < $length && !$windows && @is_readable('/dev/urandom')) {
62:             $bytes = file_get_contents('/dev/urandom', FALSE, NULL, -1, $length);
63:         }
64:         if (strlen($bytes) < $length) {
65:             $rand3 = md5(serialize($_SERVER), TRUE);
66:             $charlist = str_shuffle($charlist);
67:             for ($i = 0; $i < $length; $i++) {
68:                 if ($i % 5 === 0) {
69:                     list($rand1, $rand2) = explode(' ', microtime());
70:                     $rand1 += lcg_value();
71:                 }
72:                 $rand1 *= $chLen;
73:                 $res .= $charlist[($rand1 + $rand2 + ord($rand3[$i % strlen($rand3)])) % $chLen];
74:                 $rand1 -= (int) $rand1;
75:             }
76:             return $res;
77:         }
78: 
79:         for ($i = 0; $i < $length; $i++) {
80:             $res .= $charlist[($i + ord($bytes[$i])) % $chLen];
81:         }
82:         return $res;
83:     }
84: 
85: }
86: