--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/util/pubsub.lua	Sat Feb 28 23:16:27 2009 +0000
@@ -0,0 +1,60 @@
+
+local ipairs, pairs, setmetatable, type = 
+        ipairs, pairs, setmetatable, type;
+
+module "pubsub"
+
+local pubsub_node_mt = { __index = _M };
+
+function new_node(name)
+	return setmetatable({ name = name, subscribers = {} }, pubsub_node_mt);
+end
+
+function set_subscribers(node, subscribers_list, list_type)
+	local subscribers = node.subscribers;
+	
+	if list_type == "array" then
+		for _, jid in ipairs(subscribers_list) do
+			if not subscribers[jid] then
+				node:add_subscriber(jid);
+			end
+		end
+	elseif (not list_type) or list_type == "set" then
+		for jid in pairs(subscribers_list) do
+			if type(jid) == "string" then
+				node:add_subscriber(jid);
+			end
+		end
+	end
+end
+
+function get_subscribers(node)
+	return node.subscribers;
+end
+
+function publish(node, item, dispatcher, data)
+	local subscribers = node.subscribers;
+	for i = 1,#subscribers do
+		item.attr.to = subscribers[i];
+		dispatcher(data, item);
+	end
+end
+
+function add_subscriber(node, jid)
+	local subscribers = node.subscribers;
+	if not subscribers[jid] then
+		local space = #subscribers;
+		subscribers[space] = jid;
+		subscribers[jid] = space;
+	end
+end
+
+function remove_subscriber(node, subscriber)
+	local subscribers = node.subscribers;
+	if subscribers[jid] then
+		subscribers[subscribers[jid]] = nil;
+		subscribers[jid] = nil;
+	end
+end
+
+return _M;