luatz/timetable: Rename `increment` to `carry`

diff --git a/luatz/timetable.lua b/luatz/timetable.lua
index 99ac52ee8d238f85e350e5e4ed2a92b1fa6b32b6..879f0a226fe6839b8c5424112d0945a91899063c 100644 (file)
--- a/luatz/timetable.lua
+++ b/luatz/timetable.lua
@@ -56,7 +56,7 @@ local function day_of_week ( day , month , year )
        return ( year + leap_years_since ( year ) + sakamoto[month] + day ) % 7 + 1
 end
 
-local function increment ( tens , units , base )
+local function carry ( tens , units , base )
        if units >= base then
                tens  = tens + idiv ( units , base )
                units = units % base
@@ -69,9 +69,11 @@ end
 
 -- Modify parameters so they all fit within the "normal" range
 local function normalise ( year , month , day , hour , min , sec )
-       min  , sec  = increment ( min  , sec  , 60 ) -- TODO: consider leap seconds?
-       hour , min  = increment ( hour , min  , 60 )
-       day  , hour = increment ( day  , hour , 24 )
+       -- Propagate out of range values up
+       -- e.g. if `min` is 70, `hour` increments by 1 and `min` becomes 10
+       min   , sec   = carry ( min   , sec   , 60 ) -- TODO: consider leap seconds?
+       hour  , min   = carry ( hour  , min   , 60 )
+       day   , hour  = carry ( day   , hour  , 24 )
 
        while day <= 0 do
                year = year - 1
@@ -80,7 +82,7 @@ local function normalise ( year , month , day , hour , min , sec )
 
        -- Lua months start from 1, need -1 and +1 around this increment
        month = month - 1
-       year , month = increment ( year , month , 12 )
+       year , month = carry ( year , month , 12 )
        month = month + 1
 
        -- This could potentially be slow if `day` is very large