src/init: Export timetable from main module

[etc/awesome.git] / src / timetable.lua

diff --git a/src/timetable.lua b/src/timetable.lua
index 5fa720542d33945defe25b6a50ee2e33384bbde5..d1cd534a624f8c8653929b72dd556e1966601027 100644 (file)
--- a/src/timetable.lua
+++ b/src/timetable.lua
@@ -1,3 +1,4 @@
+local strformat = string.format
 local floor = math.floor
 local function idiv ( n , d )
        return floor ( n / d )
@@ -20,6 +21,7 @@ local function year_length ( y )
 end
 
 local function month_length ( m , y )
+       m = ( m - 1 ) % 12 + 1
        if m == 2 then
                return is_leap ( y ) and 29 or 28
        else
@@ -27,9 +29,13 @@ local function month_length ( m , y )
        end
 end
 
+local function leap_years_since ( year )
+       return idiv ( year , 4 ) - idiv ( year , 100 ) + idiv ( year , 400 )
+end
+
 local function doomsday ( year )
        return ( 3 -- Tuesday
-               - 1 + year + idiv ( year , 4 ) - idiv ( year , 100 ) + idiv ( year , 400 ) )
+               - 1 + year + leap_years_since ( year ) )
                % 7 + 1
 end
 local doomsday_cache = setmetatable ( { } , {
@@ -69,7 +75,9 @@ local function unpack_tm ( tm )
                assert ( tm.day   , "day required" ) ,
                tm.hour or 12 ,
                tm.min  or 0 ,
-               tm.sec  or 0
+               tm.sec  or 0 ,
+               tm.yday ,
+               tm.wday
 end
 
 -- Modify parameters so they all fit within the "normal" range
@@ -98,12 +106,16 @@ 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
@@ -134,15 +146,36 @@ function timetable_methods:timestamp ( )
        return timestamp ( unpack_tm ( self ) )
 end
 
-local timetable_mt = {
+function timetable_methods:rfc_3339 ( )
+       -- %06.4g gives 3 (=6-4+1) digits after decimal
+       return strformat ( "%04u-%02u-%02uT%02u:%02u:%06.4g" , unpack_tm ( self ) )
+end
+
+local timetable_mt
+
+local function coerce_arg ( t )
+       if getmetatable ( t ) == timetable_mt then
+               return t:timestamp ( )
+       end
+       return t
+end
+
+timetable_mt = {
        __index    = timetable_methods ;
+       __tostring = timetable_methods.rfc_3339 ;
+       __eq = function ( a , b )
+               return coerce_arg ( a ) == coerce_arg ( b )
+       end ;
+       __lt = function ( a , b )
+               return coerce_arg ( a ) < coerce_arg ( b )
+       end ;
 }
 
 local function cast_timetable ( tm )
        return setmetatable ( tm , timetable_mt )
 end
 
-local function new_timetable ( year , month , day , hour , min , sec )
+local function new_timetable ( year , month , day , hour , min , sec , yday , wday )
        return cast_timetable {
                year  = year ;
                month = month ;
@@ -150,15 +183,26 @@ local function new_timetable ( year , month , day , hour , min , sec )
                hour  = hour ;
                min   = min ;
                sec   = sec ;
+               yday  = yday ;
+               wday  = wday ;
        }
 end
 
+function timetable_methods:clone ( )
+       return new_timetable ( unpack_tm ( self ) )
+end
+
+local function new_from_timestamp ( ts )
+       return new_timetable ( 1970 , 1 , 1 , 0 , 0 , ts )
+end
+
 return {
        doomsday  = doomsday ;
        normalise = normalise ;
        timestamp = timestamp ;
 
        new = new_timetable ;
+       new_from_timestamp = new_from_timestamp ;
        cast = cast_timetable ;
        timetable_mt = timetable_mt ;
 }