+local strftime = require "luatz.strftime".strftime
local strformat = string.format
local floor = math.floor
local function idiv ( n , d )
local sakamoto = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
local function is_leap ( y )
- return (y % 4) == 0 and (y % 100) ~= 0 or (y % 400) == 0
+ if (y % 4) ~= 0 then
+ return false
+ elseif (y % 100) ~= 0 then
+ return true
+ else
+ return (y % 400) == 0
+ end
end
local function year_length ( y )
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
-- 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
-- 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
return strformat ( "%04u-%02u-%02uT%02u:%02u:%06.3f" , self:unpack ( ) )
end
+function timetable_methods:strftime ( format_string )
+ return strftime ( format_string , self )
+end
+
local timetable_mt
local function coerce_arg ( t )
__index = timetable_methods ;
__tostring = timetable_methods.rfc_3339 ;
__eq = function ( a , b )
- return coerce_arg ( a ) == coerce_arg ( b )
+ return a:timestamp ( ) == b:timestamp ( )
end ;
__lt = function ( a , b )
- return coerce_arg ( a ) < coerce_arg ( b )
+ return a:timestamp ( ) < b:timestamp ( )
+ end ;
+ __sub = function ( a , b )
+ return coerce_arg ( a ) - coerce_arg ( b )
end ;
}
end
local function new_from_timestamp ( ts )
+ if type ( ts ) ~= "number" then
+ error ( "bad argument #1 to 'new_from_timestamp' (number expected, got " .. type ( ts ) .. ")" , 2 )
+ end
return new_timetable ( 1970 , 1 , 1 , 0 , 0 , ts )
end
return {
+ is_leap = is_leap ;
day_of_year = day_of_year ;
day_of_week = day_of_week ;
normalise = normalise ;