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util/uuid.lua @ 2573:60493186fef6
net.dns: Removed some useless indirection to improve readability.
author | Waqas Hussain <waqas20@gmail.com> |
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date | Wed, 10 Feb 2010 00:34:30 +0500 |
parent | 1523:841d61be198f |
child | 2923:b7049746bd29 |
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-- Prosody IM -- Copyright (C) 2008-2009 Matthew Wild -- Copyright (C) 2008-2009 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local m_random = math.random; local tostring = tostring; local os_time = os.time; local os_clock = os.clock; local sha1 = require "util.hashes".sha1; module "uuid" local last_uniq_time = 0; local function uniq_time() local new_uniq_time = os_time(); if last_uniq_time >= new_uniq_time then new_uniq_time = last_uniq_time + 1; end last_uniq_time = new_uniq_time; return new_uniq_time; end local function new_random(x) return sha1(x..os_clock()..tostring({}), true); end local buffer = new_random(uniq_time()); local function _seed(x) buffer = new_random(buffer..x); end local function get_nibbles(n) if #buffer < n then seed(uniq_time()); end local r = buffer:sub(0, n); buffer = buffer:sub(n+1); return r; end local function get_twobits() return ("%x"):format(get_nibbles(1):byte() % 4 + 8); end function generate() -- generate RFC 4122 complaint UUIDs (version 4 - random) return get_nibbles(8).."-"..get_nibbles(4).."-4"..get_nibbles(3).."-"..(get_twobits())..get_nibbles(3).."-"..get_nibbles(12); end seed = _seed; return _M;