util/uuid.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2010 Matthew Wild
   3 -- Copyright (C) 2008-2010 Waqas Hussain
   4 --
   5 -- This project is MIT/X11 licensed. Please see the
   6 -- COPYING file in the source package for more information.
   7 --
   8
   9 local random = require "util.random";
  10 local random_bytes = random.bytes;
  11 local hex = require "util.hex".to;
  12 local m_ceil = math.ceil;
  13
  14 local function get_nibbles(n)
  15         return hex(random_bytes(m_ceil(n/2))):sub(1, n);
  16 end
  17
  18 local function get_twobits()
  19         return ("%x"):format(random_bytes(1):byte() % 4 + 8);
  20 end
  21
  22 local function generate()
  23         -- generate RFC 4122 complaint UUIDs (version 4 - random)
  24         return get_nibbles(8).."-"..get_nibbles(4).."-4"..get_nibbles(3).."-"..(get_twobits())..get_nibbles(3).."-"..get_nibbles(12);
  25 end
  26
  27 return {
  28         get_nibbles=get_nibbles;
  29         generate = generate ;
  30         -- COMPAT
  31         seed = random.seed;
  32 };