Fix upcoming deprecation of mt_rand on newer php versions

* provide a workaround function in code/Common like is_php does
* closes bcit-ci/CodeIgniter#6275
* related to pocketarc/codeigniter#3 (comment)

Author: mckaygerhard

appsys/core/Common.php

@@ -57,6 +57,38 @@ function is_php($version = '5.0.0')
 
 // ------------------------------------------------------------------------
 
+/**
+ * implements internally the rand specific function based on PHP version, used internally
+ *
+ * @access	public
+ * @param	int or 0
+ * @param	int or mt_getrandmax()
+ * @return	int
+ */
+if ( ! function_exists('php_rand'))
+{
+	/**
+	 * implements internally the rand specific function based on PHP version, used internally
+	 *
+	 * @param	int or 0
+	 * @param	int or mt_getrandmax()
+	 * @return	int
+	 */
+	function php_rand($min = NULL, $max = NULL)
+	{
+		if(!is_int($min) $min = 0;
+		if(!is_int($max) $max = mt_getrandmax();
+
+		if( is_php('7.1.99') ) return random_int($min, $max);
+
+		if (!function_exists('mcrypt_create_iv')) trigger_error( 'mcrypt must be loaded for random_int to work', E_USER_WARNING );
+
+		return mt_rand($min, $max);
+	}
+}
+
+// ------------------------------------------------------------------------
+
 /**
  * Tests for file writability
  *

appsys/core/Security.php

@@ -488,7 +488,7 @@ public function xss_hash()
 		if ($this->_xss_hash == '')
 		{
 			mt_srand();
-			$this->_xss_hash = md5(time() + mt_rand(0, 1999999999));
+			$this->_xss_hash = md5(time() + php_rand(0, 1999999999));
 		}
 
 		return $this->_xss_hash;

appsys/helpers/captcha_helper.php

@@ -187,7 +187,7 @@ function create_captcha($data = '', $img_path = '', $img_url = '', $font_path =
 		{
 			for ($i = 0; $i < $word_length; $i++)
 			{
-				$word .= $pool[mt_rand(0, $rand_max)];
+				$word .= $pool[php_rand(0, $rand_max)];
 			}
 		}
 		elseif ( ! is_string($word))

appsys/helpers/string_helper.php

@@ -197,7 +197,7 @@ function random_string($type = 'alnum', $len = 8)
 	{
 		switch($type)
 		{
-			case 'basic'	: return mt_rand();
+			case 'basic'	: return php_rand();
 				break;
 			case 'alnum'	:
 			case 'numeric'	:
@@ -219,22 +219,22 @@ function random_string($type = 'alnum', $len = 8)
 					$str = '';
 					for ($i=0; $i < $len; $i++)
 					{
-						$str .= substr($pool, mt_rand(0, strlen($pool) -1), 1);
+						$str .= substr($pool, php_rand(0, strlen($pool) -1), 1);
 					}
 					return $str;
 				break;
 			case 'unique'	:
 			case 'md5'		:
 
-						return md5(uniqid(mt_rand()));
+						return md5(uniqid(php_rand()));
 				break;
 			case 'encrypt'	:
 			case 'sha1'	:
 
 						$CI =& get_instance();
 						$CI->load->helper('security');
 
-						return do_hash(uniqid(mt_rand(), TRUE), 'sha1');
+						return do_hash(uniqid(php_rand(), TRUE), 'sha1');
 				break;
 		}
 	}

appsys/libraries/Encrypt.php

@@ -247,7 +247,7 @@ function _xor_encode($string, $key)
 		$rand = '';
 		while (strlen($rand) < 32)
 		{
-			$rand .= mt_rand(0, mt_getrandmax());
+			$rand .= php_rand(0, mt_getrandmax());
 		}
 
 		$rand = $this->hash($rand);

appsys/libraries/Session.php

@@ -328,7 +328,7 @@ function sess_create()
 		$sessid = '';
 		while (strlen($sessid) < 32)
 		{
-			$sessid .= mt_rand(0, mt_getrandmax());
+			$sessid .= php_rand(0, mt_getrandmax());
 		}
 
 		// To make the session ID even more secure we'll combine it with the user's IP
@@ -375,7 +375,7 @@ function sess_update()
 		$new_sessid = '';
 		while (strlen($new_sessid) < 32)
 		{
-			$new_sessid .= mt_rand(0, mt_getrandmax());
+			$new_sessid .= php_rand(0, mt_getrandmax());
 		}
 
 		// To make the session ID even more secure we'll combine it with the user's IP

appsys/libraries/Upload.php

@@ -397,7 +397,7 @@ public function set_filename($path, $filename)
 		if ($this->encrypt_name == TRUE)
 		{
 			mt_srand();
-			$filename = md5(uniqid(mt_rand())).$this->file_ext;
+			$filename = md5(uniqid(php_rand())).$this->file_ext;
 		}
 
 		if ( ! file_exists($path.$filename)) // if ($this->overwrite === TRUE OR ! file_exists($path.$filename)) // permite que asigne nombre nuevo no importa si esta permitido