1 files changed, 211 insertions, 0 deletions
diff --git a/mesecons/util.lua b/mesecons/util.lua
new file mode 100644
index 0000000..dd33f1c
--- /dev/null
+++ b/mesecons/util.lua
@@ -0,0 +1,211 @@
+function mesecon.move_node(pos, newpos)
+	local node = minetest.get_node(pos)
+	local meta = minetest.get_meta(pos):to_table()
+	minetest.remove_node(pos)
+	minetest.add_node(newpos, node)
+	minetest.get_meta(pos):from_table(meta)
+end
+
+function mesecon.flattenrules(allrules)
+--[[
+	{
+		{
+			{xyz},
+			{xyz},
+		},
+		{
+			{xyz},
+			{xyz},
+		},
+	}
+--]]
+	if allrules[1] and
+	   allrules[1].x then
+		return allrules
+	end
+
+	local shallowrules = {}
+	for _, metarule in ipairs( allrules) do
+	for _,     rule in ipairs(metarule ) do
+		table.insert(shallowrules, rule)
+	end
+	end
+	return shallowrules
+--[[
+	{
+		{xyz},
+		{xyz},
+		{xyz},
+		{xyz},
+	}
+--]]
+end
+
+function mesecon.rule2bit(findrule, allrules)
+	--get the bit of the metarule the rule is in, or bit 1
+	if (allrules[1] and
+	    allrules[1].x) or
+	    not findrule then
+		return 1
+	end
+	for m,metarule in ipairs( allrules) do
+	for _,    rule in ipairs(metarule ) do
+		if mesecon.cmpPos(findrule, rule) then
+			return m
+		end
+	end
+	end
+end
+
+function mesecon.rule2metaindex(findrule, allrules)
+	--get the metarule the rule is in, or allrules
+	if allrules[1].x then
+		return nil
+	end
+
+	if not(findrule) then
+		return mesecon.flattenrules(allrules)
+	end
+
+	for m, metarule in ipairs( allrules) do
+	for _,     rule in ipairs(metarule ) do
+		if mesecon.cmpPos(findrule, rule) then
+			return m
+		end
+	end
+	end
+end
+
+function mesecon.rule2meta(findrule, allrules)
+	if #allrules == 0 then return {} end
+
+	local index = mesecon.rule2metaindex(findrule, allrules)
+	if index == nil then
+		if allrules[1].x then
+			return allrules
+		else
+			return {}
+		end
+	end
+	return allrules[index]
+end
+
+function mesecon.dec2bin(n)
+	local x, y = math.floor(n / 2), n % 2
+	if (n > 1) then
+		return mesecon.dec2bin(x)..y
+	else
+		return ""..y
+	end
+end
+
+function mesecon.getstate(nodename, states)
+	for state, name in ipairs(states) do
+		if name == nodename then
+			return state
+		end
+	end
+	error(nodename.." doesn't mention itself in "..dump(states))
+end
+
+function mesecon.getbinstate(nodename, states)
+	return mesecon.dec2bin(mesecon.getstate(nodename, states)-1)
+end
+
+function mesecon.get_bit(binary,bit)
+	bit = bit or 1
+	local c = binary:len()-(bit-1)
+	return binary:sub(c,c) == "1"
+end
+
+function mesecon.set_bit(binary,bit,value)
+	if value == "1" then
+		if not mesecon.get_bit(binary,bit) then
+			return mesecon.dec2bin(tonumber(binary,2)+math.pow(2,bit-1))
+		end
+	elseif value == "0" then
+		if mesecon.get_bit(binary,bit) then
+			return mesecon.dec2bin(tonumber(binary,2)-math.pow(2,bit-1))
+		end
+	end
+	return binary
+
+end
+
+function mesecon.invertRule(r)
+	return {x = -r.x, y = -r.y, z = -r.z}
+end
+
+function mesecon.addPosRule(p, r)
+	return {x = p.x + r.x, y = p.y + r.y, z = p.z + r.z}
+end
+
+function mesecon.cmpPos(p1, p2)
+	return (p1.x == p2.x and p1.y == p2.y and p1.z == p2.z)
+end
+
+function mesecon.tablecopy(table) -- deep table copy
+	if type(table) ~= "table" then return table end -- no need to copy
+	local newtable = {}
+
+	for idx, item in pairs(table) do
+		if type(item) == "table" then
+			newtable[idx] = mesecon.tablecopy(item)
+		else
+			newtable[idx] = item
+		end
+	end
+
+	return newtable
+end
+
+function mesecon.cmpAny(t1, t2)
+	if type(t1) ~= type(t2) then return false end
+	if type(t1) ~= "table" and type(t2) ~= "table" then return t1 == t2 end
+
+	for i, e in pairs(t1) do
+		if not mesecon.cmpAny(e, t2[i]) then return false end
+	end
+
+	return true
+end
+
+-- does not overwrite values; number keys (ipairs) are appended, not overwritten
+function mesecon.mergetable(source, dest)
+	local rval = mesecon.tablecopy(dest)
+
+	for k, v in pairs(source) do
+		rval[k] = dest[k] or mesecon.tablecopy(v)
+	end
+	for i, v in ipairs(source) do
+		table.insert(rval, mesecon.tablecopy(v))
+	end
+
+	return rval
+end
+
+function mesecon.register_node(name, spec_common, spec_off, spec_on)
+	spec_common.drop = spec_common.drop or name .. "_off"
+	spec_common.__mesecon_basename = name
+	spec_on.__mesecon_state = "on"
+	spec_off.__mesecon_state = "off"
+
+	spec_on = mesecon.mergetable(spec_common, spec_on);
+	spec_off = mesecon.mergetable(spec_common, spec_off);
+
+	minetest.register_node(name .. "_on", spec_on)
+	minetest.register_node(name .. "_off", spec_off)
+end
+
+-- swap onstate and offstate nodes, returns new state
+function mesecon.flipstate(pos, node)
+	local nodedef = minetest.registered_nodes[node.name]
+	local newstate
+	if (nodedef.__mesecon_state == "on") then newstate = "off" end
+	if (nodedef.__mesecon_state == "off") then newstate = "on" end
+
+	minetest.swap_node(pos, {name = nodedef.__mesecon_basename .. "_" .. newstate,
+		param2 = node.param2})
+
+	return newstate
+end