* lib/securerandom.rb: new method SecureRandom#uuid

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@21868 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Thu Jan 29 12:18:54 2009  Technorama Ltd.  <oss-ruby@technorama.net>
+
+	* lib/securerandom.rb: new method SecureRandom#uuid
+
 Thu Jan 29 11:22:19 2009  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/socket/raddrinfo.c (inspect_sockaddr): if defined AF_INET6,

lib/securerandom.rb

@@ -167,6 +167,16 @@ module SecureRandom
     end
   end
 
+  # SecureRandom.uuid generates a v4 random UUID.
+  def self.uuid
+    str = self.random_bytes(16)
+    str[6] = (str[6] & 0x0f) | 0x40
+    str[8] = (str[8] & 0x3f) | 0x80
+
+    ary = str.unpack("NnnnnN")
+    "%08x-%04x-%04x-%04x-%04x%08x" % ary
+  end
+
   # Following code is based on David Garamond's GUID library for Ruby.
   def self.lastWin32ErrorMessage # :nodoc:
     get_last_error = Win32API.new("kernel32", "GetLastError", '', 'L')