Rewizja sparse_set.lua

1 file changed, 40 insertions

sparse_set.lua(stworzono plik)

		@@ -0,0 +1,40 @@
1	+	local function push(self, thing)
2	+	-- Attempt to recycle a previously freed ID
3	+	local id = self.free_ids[#self.free_ids]
4	+	table.remove(self.free_ids)
5	+	if not id then
6	+	-- Othewise generate a new ID
7	+	id = self.next_id
8	+	self.next_id = self.next_id + 1
9	+	end
10	+	-- Assign the ID, the push the object into items
11	+	-- and add its position to indices.
12	+	thing.id = id
13	+	table.insert(self.items, thing)
14	+	self.indices[thing.id] = #self.items
15	+	end
16	+
17	+	local function pop(self, thing)
18	+	assert(self.indices[thing.id], "ID is not bound in this set")
19	+	assert(self.items[self.indices[thing.id]] == thing, "ID does not belong to this object")
20	+	-- Add the ID of this object to the free stack
21	+	table.insert(self.free_ids, thing.id)
22	+
23	+	-- Consume the current index
24	+	local index = self.indices[thing.id]
25	+	self.indices[thing.id] = nil
26	+
27	+	-- Swap and pop the last item in the set.
28	+	self.items[index] = self.items[#self.items]
29	+	table.remove(self.items)
30	+	end
31	+
32	+	local function each(self)
33	+	return ipairs(self.items)
34	+	end
35	+
36	+	local function sparse_set()
37	+	return { push = push, pop = pop, each = each, items = {}, indices = {}, free_ids = {}, next_id = 1 }
38	+	end
39	+
40	+	return sparse_set

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