-- Prosody IM

-- Copyright (C) 2008-2014 Matthew Wild

-- Copyright (C) 2008-2014 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local tostring = tostring;

local os_time = os.time;

local os_clock = os.clock;

local ceil = math.ceil;

local H = require "util.hashes".sha512;

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 H(x..os_clock()..tostring({}));

end

local buffer = new_random(uniq_time());

local function seed(x)

	buffer = new_random(buffer..x);

end

local function bytes(n)

	if #buffer < n+4 then seed(uniq_time()); end

	local r = buffer:sub(1, n);

	buffer = buffer:sub(n+1);

	return r;

end

return {

	seed = seed;

	bytes = bytes;

};