X-Git-Url: https://git.madduck.net/etc/awesome.git/blobdiff_plain/81eaf243f3f28403292343af73e178f79ab5c0b3..d535197d4d94122f86a485aac740bc7329664129:/src/timetable.lua

diff --git a/src/timetable.lua b/src/timetable.lua
index 9af7994..c71c59b 100644
--- a/src/timetable.lua
+++ b/src/timetable.lua
@@ -63,14 +63,17 @@ local function increment ( tens , units , base )
 	return tens , units
 end
 
-local function normalise ( tm )
-	local sec   = tm.sec  or 0
-	local min   = tm.min  or 0
-	local hour  = tm.hour or 12
-	local day   = assert ( tm.day   , "day required" )
-	local month = assert ( tm.month , "month required" )
-	local year  = assert ( tm.year  , "year required" )
+local function unpack_tm ( tm )
+	return assert ( tm.year  , "year required" ) ,
+		assert ( tm.month , "month required" ) ,
+		assert ( tm.day   , "day required" ) ,
+		tm.hour or 12 ,
+		tm.min  or 0 ,
+		tm.sec  or 0
+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 )
@@ -92,23 +95,79 @@ local function normalise ( tm )
 	year , month = increment ( year , month - 1 , 12 )
 	month = month + 1
 
-	tm.sec   = sec
-	tm.min   = min
-	tm.hour  = hour
-	tm.day   = day
-	tm.month = month
-	tm.year  = year
+	return year , month , day , hour , min , sec
+end
+
+local function timestamp ( year , month , day , hour , min , sec )
+	return 60*60*24*(
+			year * year_length ( year )
+			+ month * month_length ( month , year )
+			+ day
+		)
+		+ hour  * (60*60)
+		+ min   * 60
+		+ sec
+end
+
+
+local timetable_methods = { }
+
+function timetable_methods:normalise ( )
+	local year , month , day
+	year , month , day , self.hour , self.min , self.sec = normalise ( unpack_tm ( self ) )
+
+	self.day   = day
+	self.month = month
+	self.year  = year
 
 	local yday = day_of_year ( day , month , year )
 	local wday = day_of_week ( yday , year )
 
-	tm.yday = yday
-	tm.wday = wday
+	self.yday = yday
+	self.wday = wday
+
+	return self
+end
+timetable_methods.normalize = timetable_methods.normalise -- American English
+
+function timetable_methods:timestamp ( )
+	return timestamp ( unpack_tm ( self ) )
+end
+
+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 = {
+	__index    = timetable_methods ;
+	__tostring = timetable_methods.rfc_3339 ;
+	__eq = function ( a , b )
+		return a:timestamp() < b:timestamp()
+	end ;
+}
 
-	return tm
+local function cast_timetable ( tm )
+	return setmetatable ( tm , timetable_mt )
+end
+
+local function new_timetable ( year , month , day , hour , min , sec )
+	return cast_timetable {
+		year  = year ;
+		month = month ;
+		day   = day ;
+		hour  = hour ;
+		min   = min ;
+		sec   = sec ;
+	}
 end
 
 return {
 	doomsday  = doomsday ;
 	normalise = normalise ;
+	timestamp = timestamp ;
+
+	new = new_timetable ;
+	cast = cast_timetable ;
+	timetable_mt = timetable_mt ;
 }