1 files changed, 102 insertions, 0 deletions
diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
new file mode 100644
index 0000000..e604f9b
--- /dev/null
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -0,0 +1,102 @@
+type2defs = {}
+
+local function register_type2(def)
+	local t = {type = 2}
+	local name = def.name
+	if type2defs[name] then
+		return error("Name " .. name .. " already used")
+	elseif type(name) ~= "string" then
+		return error("Name is not a string")
+	end
+	t.name = name
+
+	local label = def.label or name
+	if type(label) ~= "string" then
+		return error("Label is not a string")
+	end
+	t.label = label
+
+	local mainasps = {}
+	for idx, asp in ipairs(def.main) do
+		local t = {}
+		local name = asp.name
+		if type(name) ~= "string" then
+			return error("Aspect name is not a string")
+		end
+		t.name = name
+
+		local label = asp.label or name
+		if type(label) ~= "string" then
+			return error("Aspect label is not a string")
+		end
+		t.label = label
+
+		t.main = asp.main
+		mainasps[idx] = t
+		mainasps[name] = idx
+	end
+	t.main = mainasps
+
+	type2defs[name] = t
+end
+
+local function get_type2_definition(name)
+	return type2defs[name]
+end
+
+local function type2main_to_type1(name, asp)
+	local def = type2defs[name]
+	if not def then
+		return nil
+	end
+	local aspidx
+	if type(asp) == "number" then
+		aspidx = asp
+	else
+		aspidx = def.main[asp]
+	end
+	local asptbl = def.main[aspidx]
+	if not asptbl then
+		return nil
+	end
+	if type(asp) == "number" then
+		asp = asptbl.name
+	end
+
+	local t = {
+		main = asptbl.main,
+		type2name = asp,
+		type2group = name,
+	}
+	if aspidx ~= 1 and aspidx ~= #asptbl then
+		t.dst = def.main[aspidx+1].main
+	end
+	return t
+end
+
+local function type1_to_type2main(asp, group)
+	local def = type2defs[group]
+	if not def then
+		return nil
+	end
+	if group == asp.type2group and def.main[asp.type2name] then
+		return asp.type2name
+	end
+	local t_main = def.main
+	local idx
+	if not asp.main or asp.main == -1 then
+		idx = 1
+	elseif asp.main == 0 then
+		idx = #t_main
+	else
+		idx = math.max(#t_main-1, 1)
+	end
+	return t_main[idx].name
+end
+
+return {
+	register_type2 = register_type2,
+	get_type2_definition = get_type2_definition,
+	type2main_to_type1 = type2main_to_type1,
+	type1_to_type2main = type1_to_type2main,
+}