Random: use constant for windows test

BigInteger: Docblock adjustments

phpseclib/Crypt/Random.php

@@ -42,6 +42,13 @@
  * @link       http://phpseclib.sourceforge.net
  */
 
+/**
+ * "Is Windows" test
+ *
+ * @access private
+ */
+define('CRYPT_RANDOM_IS_WINDOWS', strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');
+
 /**
  * Generate a random string.
  *
@@ -56,7 +63,7 @@
 function crypt_random_string($length)
 {
     // PHP_OS & "\xDF\xDF\xDF" == strtoupper(substr(PHP_OS, 0, 3)), but a lot faster
-    if ((PHP_OS & "\xDF\xDF\xDF") === 'WIN') {
+    if (CRYPT_RANDOM_IS_WINDOWS) {
         // method 1. prior to PHP 5.3 this would call rand() on windows hence the function_exists('class_alias') call.
         // ie. class_alias is a function that was introduced in PHP 5.3
         if (function_exists('mcrypt_create_iv') && function_exists('class_alias')) {

phpseclib/Math/BigInteger.php

@@ -236,20 +236,20 @@ class Math_BigInteger {
     var $hex;
 
     /**
-     * Converts base-2, base-10, base-16, and binary strings (eg. base-256) to BigIntegers.
+     * Converts base-2, base-10, base-16, and binary strings (base-256) to BigIntegers.
      *
      * If the second parameter - $base - is negative, then it will be assumed that the number's are encoded using
      * two's compliment.  The sole exception to this is -10, which is treated the same as 10 is.
      *
      * Here's an example:
      * <code>
-     * <?php
+     * &lt;?php
      *    include('Math/BigInteger.php');
      *
      *    $a = new Math_BigInteger('0x32', 16); // 50 in base-16
      *
      *    echo $a->toString(); // outputs 50
-     * ?>
+     * ?&gt;
      * </code>
      *
      * @param optional $x base-10 number or base-$base number if $base set.