X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=util%2Fset.lua;h=e4cc2dffbd428b6be84c2ec749ba0cd2156b67b3;hb=a689938fa45323f67433bcd5554affd3f4b0fc52;hp=67f3dcaabfb37bd445bf99b85bb41b24cc2d095c;hpb=cbaa12fe71fafacc60596ba6fe21f54267ca525a;p=prosody.git

diff --git a/util/set.lua b/util/set.lua
index 67f3dcaa..e4cc2dff 100644
--- a/util/set.lua
+++ b/util/set.lua
@@ -1,11 +1,69 @@
-local ipairs, pairs = 
-      ipairs, pairs;
+-- Prosody IM
+-- Copyright (C) 2008-2010 Matthew Wild
+-- Copyright (C) 2008-2010 Waqas Hussain
+-- 
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local ipairs, pairs, setmetatable, next, tostring =
+      ipairs, pairs, setmetatable, next, tostring;
+local t_concat = table.concat;
 
 module "set"
 
+local set_mt = {};
+function set_mt.__call(set, _, k)
+	return next(set._items, k);
+end
+function set_mt.__add(set1, set2)
+	return _M.union(set1, set2);
+end
+function set_mt.__sub(set1, set2)
+	return _M.difference(set1, set2);
+end
+function set_mt.__div(set, func)
+	local new_set, new_items = _M.new();
+	local items, new_items = set._items, new_set._items;
+	for item in pairs(items) do
+		if func(item) then
+			new_items[item] = true;
+		end
+	end
+	return new_set;
+end
+function set_mt.__eq(set1, set2)
+	local set1, set2 = set1._items, set2._items;
+	for item in pairs(set1) do
+		if not set2[item] then
+			return false;
+		end
+	end
+	
+	for item in pairs(set2) do
+		if not set1[item] then
+			return false;
+		end
+	end
+	
+	return true;
+end
+function set_mt.__tostring(set)
+	local s, items = { }, set._items;
+	for item in pairs(items) do
+		s[#s+1] = tostring(item);
+	end
+	return t_concat(s, ", ");
+end
+
+local items_mt = {};
+function items_mt.__call(items, _, k)
+	return next(items, k);
+end
+
 function new(list)
-	local items = {};
-	local set = { items = items };
+	local items = setmetatable({}, items_mt);
+	local set = { _items = items };
 	
 	function set:add(item)
 		items[item] = true;
@@ -41,22 +99,26 @@ function new(list)
 		end
 	end
 	
+	function set:empty()
+		return not next(items);
+	end
+	
 	if list then
 		set:add_list(list);
 	end
 	
-	return set;
+	return setmetatable(set, set_mt);
 end
 
 function union(set1, set2)
 	local set = new();
-	local items = set.items;
+	local items = set._items;
 	
-	for item in pairs(set1.items) do
+	for item in pairs(set1._items) do
 		items[item] = true;
 	end
 
-	for item in pairs(set2.items) do
+	for item in pairs(set2._items) do
 		items[item] = true;
 	end
 	
@@ -65,17 +127,30 @@ end
 
 function difference(set1, set2)
 	local set = new();
-	local items = set.items;
+	local items = set._items;
 	
-	for item in pairs(set1.items) do
-		items[item] = true;
+	for item in pairs(set1._items) do
+		items[item] = (not set2._items[item]) or nil;
 	end
 
-	for item in pairs(set2.items) do
-		items[item] = nil;
+	return set;
+end
+
+function intersection(set1, set2)
+	local set = new();
+	local items = set._items;
+	
+	set1, set2 = set1._items, set2._items;
+	
+	for item in pairs(set1) do
+		items[item] = (not not set2[item]) or nil;
 	end
 	
 	return set;
 end
 
+function xor(set1, set2)
+	return union(set1, set2) - intersection(set1, set2);
+end
+
 return _M;