util/multitable.lua

-- Prosody IM
-- Copyright (C) 2008-2009 Matthew Wild
-- Copyright (C) 2008-2009 Waqas Hussain
-- 
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--


local select = select;
local t_insert = table.insert;
local pairs = pairs;
local next = next;

module "multitable"

local function get(self, ...)
	local t = self.data;
	for n = 1,select('#', ...) do
		t = t[select(n, ...)];
		if not t then break; end
	end
	return t;
end

local function add(self, ...)
	local t = self.data;
	local count = select('#', ...);
	for n = 1,count-1 do
		local key = select(n, ...);
		local tab = t[key];
		if not tab then tab = {}; t[key] = tab; end
		t = tab;
	end
	t_insert(t, (select(count, ...)));
end

local function set(self, ...)
	local t = self.data;
	local count = select('#', ...);
	for n = 1,count-2 do
		local key = select(n, ...);
		local tab = t[key];
		if not tab then tab = {}; t[key] = tab; end
		t = tab;
	end
	t[(select(count-1, ...))] = (select(count, ...));
end

local function r(t, n, _end, ...)
	if t == nil then return; end
	local k = select(n, ...);
	if n == _end then
		t[k] = nil;
		return;
	end
	if k then
		local v = t[k];
		if v then
			r(v, n+1, _end, ...);
			if not next(v) then
				t[k] = nil;
			end
		end
	else
		for _,b in pairs(t) do
			r(b, n+1, _end, ...);
			if not next(b) then
				t[_] = nil;
			end
		end
	end
end

local function remove(self, ...)
	local _end = select('#', ...);
	for n = _end,1 do
		if select(n, ...) then _end = n; break; end
	end
	r(self.data, 1, _end, ...);
end


local function s(t, n, results, _end, ...)
	if t == nil then return; end
	local k = select(n, ...);
	if n == _end then
		if k == nil then
			for _, v in pairs(t) do
				t_insert(results, v);
			end
		else
			t_insert(results, t[k]);
		end
		return;
	end
	if k then
		local v = t[k];
		if v then
			s(v, n+1, results, _end, ...);
		end
	else
		for _,b in pairs(t) do
			s(b, n+1, results, _end, ...);
		end
	end
end

-- Search for keys, nil == wildcard
local function search(self, ...)
	local _end = select('#', ...);
	for n = _end,1 do
		if select(n, ...) then _end = n; break; end
	end
	local results = {};
	s(self.data, 1, results, _end, ...);
	return results;
end

-- Append results to an existing list
local function search_add(self, results, ...)
	if not results then results = {}; end
	local _end = select('#', ...);
	for n = _end,1 do
		if select(n, ...) then _end = n; break; end
	end
	s(self.data, 1, results, _end, ...);
	return results;
end

function new()
	return {
		data = {};
		get = get;
		add = add;
		set = set;
		remove = remove;
		search = search;
		search_add = search_add;
	};
end

return _M;