src/timetable: Fix timestamp function; add test

diff --git a/spec/timetable_spec.lua b/spec/timetable_spec.lua
index a72a0f9b50a5db77ea019b7103f4884a3f329466..a80b9ad83a09675e857200a513384f894fe4e44b 100644 (file)
--- a/spec/timetable_spec.lua
+++ b/spec/timetable_spec.lua
@@ -34,4 +34,18 @@ describe ( "Time table library" , function ( )
                assert_same_wday ( 2013 , 7 , 28 )
                assert_same_wday ( 2013 , 7 , 29 )
        end )
+
+       local function native_timestamp ( year , month , day )
+               return assert ( tonumber ( assert ( io.popen (
+                                               string.format('date -u -d "%d-%d-%d" +%%s', year , month , day )
+                                       ) ):read "*l" ) )
+       end
+
+       it ( "Timestamp creation is valid" , function ( )
+               for y=1950,2013 do
+                       for m=1,12 do
+                               assert.same ( native_timestamp ( y,m,1 ) , timetable.timestamp(y,m,1,0,0,0) )
+                       end
+               end
+       end)
 end )

diff --git a/src/timetable.lua b/src/timetable.lua
index b58ad0f531cc8386904e5aca72a8d21445126e44..e7f28167cb7bf87c58ccc38d79b72d2638abf23f 100644 (file)
--- a/src/timetable.lua
+++ b/src/timetable.lua
@@ -102,12 +102,16 @@ local function normalise ( year , month , day , hour , min , sec )
        return year , month , day , hour , min , sec
 end
 
+local leap_years_since_1970 = leap_years_since ( 1970 )
 local function timestamp ( year , month , day , hour , min , sec )
-       return 60*60*24*(
-                       year * year_length ( year )
-                       + month * month_length ( month , year )
-                       + day
-               )
+       year , month , day , hour , min , sec = normalise ( year , month , day , hour , min , sec )
+
+       local days_since_epoch = day_of_year ( day , month , year )
+               + 365 * ( year - 1970 )
+               -- Each leap year adds one day
+               + ( leap_years_since ( year - 1 ) - leap_years_since_1970 ) - 1
+
+       return days_since_epoch * 60*60*24
                + hour  * (60*60)
                + min   * 60
                + sec