--- a/util/timer.lua	Wed Oct 30 17:30:35 2013 -0400
+++ b/util/timer.lua	Wed Oct 30 17:44:42 2013 -0400
@@ -6,6 +6,8 @@
 -- COPYING file in the source package for more information.
 --
 
+local indexedbheap = require "util.indexedbheap";
+local log = require "util.logger".init("timer");
 local server = require "net.server";
 local math_min = math.min
 local math_huge = math.huge
@@ -78,6 +80,60 @@
 	end
 end
 
-add_task = _add_task;
+--add_task = _add_task;
+
+local h = indexedbheap.create();
+local params = {};
+local next_time = nil;
+local _id, _callback, _now, _param;
+local function _call() return _callback(_now, _id, _param); end
+local function _traceback_handler(err) log("error", "Traceback[timer]: %s", traceback(tostring(err), 2)); end
+local function _on_timer(now)
+	local peek;
+	while true do
+		peek = h:peek();
+		if peek == nil or peek > now then break; end
+		local _;
+		_, _callback, _id = h:pop();
+		_now = now;
+		_param = params[id];
+		params[id] = nil;
+		--item(now, id, _param); -- FIXME pcall
+		local success, err = xpcall(_call, _traceback_handler);
+		if success and type(err) == "number" then
+			h:insert(_callback, err + now, _id); -- re-add
+		end
+	end
+	next_time = peek;
+	if peek ~= nil then
+		return peek - now;
+	end
+end
+function add_task(delay, callback, param)
+	local current_time = get_time();
+	local event_time = current_time + delay;
+
+	local id = h:insert(callback, event_time);
+	params[id] = param;
+	if next_time == nil or event_time < next_time then
+		next_time = event_time;
+		_add_task(next_time - current_time, on_timer);
+	end
+	return id;
+end
+function stop(id)
+	params[id] = nil;
+	return h:remove(id);
+end
+function reschedule(id, delay)
+	local current_time = get_time();
+	local event_time = current_time + delay;
+	h:reprioritize(id, delay);
+	if next_time == nil or event_time < next_time then
+		next_time = event_time;
+		_add_task(next_time - current_time, on_timer);
+	end
+	return id;
+end
 
 return _M;