luatz/tzfile: Make use of IDIV opcode when available (Lua 5.3+)

diff --git a/luatz/timetable.lua b/luatz/timetable.lua
index 7058d7f5cfbac828f0a5fd4f3d776d3309446e94..783d60b0170c7226d6aa0bb77d162fcdb6e8ce1b 100644 (file)
--- a/luatz/timetable.lua
+++ b/luatz/timetable.lua
@@ -1,8 +1,16 @@
 local strftime = require "luatz.strftime".strftime
 local strformat = string.format
 local floor = math.floor
-local function idiv ( n , d )
-       return floor ( n / d )
+local idiv do
+       -- Try and use actual integer division when available (Lua 5.3+)
+       local idiv_loader, err = (loadstring or load)([[return function(n,d) return n//d end]], "idiv")
+       if idiv_loader then
+               idiv = idiv_loader()
+       else
+               idiv = function(n, d)
+                       return floor(n/d)
+               end
+       end
 end