X-Git-Url: https://git.madduck.net/etc/awesome.git/blobdiff_plain/a7f02985caf20b40b60fc4d8e0b84b0483ce1865..74d5923767607c935fff45129486ff9c4251c283:/luatz/timetable.lua?ds=sidebyside diff --git a/luatz/timetable.lua b/luatz/timetable.lua index 812d497..1a304e2 100644 --- a/luatz/timetable.lua +++ b/luatz/timetable.lua @@ -14,16 +14,16 @@ local idiv do end -local mon_lengths = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } +local mon_lengths = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} -- Number of days in year until start of month; not corrected for leap years -local months_to_days_cumulative = { 0 } +local months_to_days_cumulative = {0} for i = 2, 12 do - months_to_days_cumulative [ i ] = months_to_days_cumulative [ i-1 ] + mon_lengths [ i-1 ] + months_to_days_cumulative[i] = months_to_days_cumulative[i-1] + mon_lengths[i-1] end -- For Sakamoto's Algorithm (day of week) local sakamoto = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4}; -local function is_leap ( y ) +local function is_leap(y) if (y % 4) ~= 0 then return false elseif (y % 100) ~= 0 then @@ -33,72 +33,72 @@ local function is_leap ( y ) end end -local function month_length ( m , y ) +local function month_length(m, y) if m == 2 then - return is_leap ( y ) and 29 or 28 + return is_leap(y) and 29 or 28 else - return mon_lengths [ m ] + return mon_lengths[m] end end -local function leap_years_since ( year ) - return idiv ( year , 4 ) - idiv ( year , 100 ) + idiv ( year , 400 ) +local function leap_years_since(year) + return idiv(year, 4) - idiv(year, 100) + idiv(year, 400) end -local function day_of_year ( day , month , year ) - local yday = months_to_days_cumulative [ month ] - if month > 2 and is_leap ( year ) then +local function day_of_year(day, month, year) + local yday = months_to_days_cumulative[month] + if month > 2 and is_leap(year) then yday = yday + 1 end return yday + day end -local function day_of_week ( day , month , year ) +local function day_of_week(day, month, year) if month < 3 then year = year - 1 end - return ( year + leap_years_since ( year ) + sakamoto[month] + day ) % 7 + 1 + return(year + leap_years_since(year) + sakamoto[month] + day) % 7 + 1 end -local function borrow ( tens , units , base ) +local function borrow(tens, units, base) local frac = tens % 1 units = units + frac * base tens = tens - frac - return tens , units + return tens, units end -local function carry ( tens , units , base ) +local function carry(tens, units, base) if units >= base then - tens = tens + idiv ( units , base ) + tens = tens + idiv(units, base) units = units % base elseif units < 0 then - tens = tens + idiv ( units , base ) - units = ( base + units ) % base + tens = tens + idiv(units, base) + units = (base + units) % base end - return tens , units + return tens, units end -- Modify parameters so they all fit within the "normal" range -local function normalise ( year , month , day , hour , min , sec ) +local function normalise(year, month, day, hour, min, sec) -- `month` and `day` start from 1, need -1 and +1 so it works modulo - month , day = month - 1 , day - 1 + month, day = month - 1, day - 1 -- Convert everything (except seconds) to an integer -- by propagating fractional components down. - year , month = borrow ( year , month , 12 ) + year , month = borrow(year , month, 12) -- Carry from month to year first, so we get month length correct in next line around leap years - year , month = carry ( year , month , 12 ) - month , day = borrow ( month , day , month_length ( floor ( month + 1 ) , year ) ) - day , hour = borrow ( day , hour , 24 ) - hour , min = borrow ( hour , min , 60 ) - min , sec = borrow ( min , sec , 60 ) + year , month = carry(year, month, 12) + month, day = borrow(month, day , month_length(floor(month + 1), year)) + day , hour = borrow(day , hour , 24) + hour , min = borrow(hour , min , 60) + min , sec = borrow(min , sec , 60) -- Propagate out of range values up -- e.g. if `min` is 70, `hour` increments by 1 and `min` becomes 10 -- This has to happen for all columns after borrowing, as lower radixes may be pushed out of range - min , sec = carry ( min , sec , 60 ) -- TODO: consider leap seconds? - hour , min = carry ( hour , min , 60 ) - day , hour = carry ( day , hour , 24 ) + min , sec = carry(min , sec , 60) -- TODO: consider leap seconds? + hour , min = carry(hour, min , 60) + day , hour = carry(day , hour, 24) -- Ensure `day` is not underflowed -- Add a whole year of days at a time, this is later resolved by adding months -- TODO[OPTIMIZE]: This could be slow if `day` is far out of range @@ -108,13 +108,13 @@ local function normalise ( year , month , day , hour , min , sec ) year = year - 1 month = 11 end - day = day + month_length ( month + 1 , year ) + day = day + month_length(month + 1, year) end - year , month = carry ( year , month , 12 ) + year, month = carry(year, month, 12) -- TODO[OPTIMIZE]: This could potentially be slow if `day` is very large while true do - local i = month_length ( month + 1 , year ) + local i = month_length(month + 1, year) if day < i then break end day = day - i month = month + 1 @@ -126,129 +126,129 @@ local function normalise ( year , month , day , hour , min , sec ) -- Now we can place `day` and `month` back in their normal ranges -- e.g. month as 1-12 instead of 0-11 - month , day = month + 1 , day + 1 + month, day = month + 1, day + 1 - return 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 ) - year , month , day , hour , min , sec = normalise ( year , month , day , hour , min , sec ) +local leap_years_since_1970 = leap_years_since(1970) +local function timestamp(year, month, day, hour, min, sec) + 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 ) + 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 + + (leap_years_since(year - 1) - leap_years_since_1970) - 1 return days_since_epoch * (60*60*24) - + hour * (60*60) - + min * 60 + + hour * (60*60) + + min * 60 + sec end -local timetable_methods = { } +local timetable_methods = {} -function timetable_methods:unpack ( ) - return assert ( self.year , "year required" ) , - assert ( self.month , "month required" ) , - assert ( self.day , "day required" ) , - self.hour or 12 , - self.min or 0 , - self.sec or 0 , - self.yday , +function timetable_methods:unpack() + return assert(self.year , "year required"), + assert(self.month, "month required"), + assert(self.day , "day required"), + self.hour or 12, + self.min or 0, + self.sec or 0, + self.yday, self.wday end -function timetable_methods:normalise ( ) - local year , month , day - year , month , day , self.hour , self.min , self.sec = normalise ( self:unpack ( ) ) +function timetable_methods:normalise() + local year, month, day + year, month, day, self.hour, self.min, self.sec = normalise(self:unpack()) self.day = day self.month = month self.year = year - self.yday = day_of_year ( day , month , year ) - self.wday = day_of_week ( day , month , year ) + self.yday = day_of_year(day, month, year) + self.wday = day_of_week(day, month, year) return self end timetable_methods.normalize = timetable_methods.normalise -- American English -function timetable_methods:timestamp ( ) - return timestamp ( self:unpack ( ) ) +function timetable_methods:timestamp() + return timestamp(self:unpack()) end -function timetable_methods:rfc_3339 ( ) +function timetable_methods:rfc_3339() local year, month, day, hour, min, fsec = self:unpack() local sec, msec = borrow(fsec, 0, 1000) msec = math.floor(msec) - return strformat ( "%04u-%02u-%02uT%02u:%02u:%02d.%03d" , year , month , day , hour , min , sec , msec ) + return strformat("%04u-%02u-%02uT%02u:%02u:%02d.%03d", year, month, day, hour, min, sec, msec) end -function timetable_methods:strftime ( format_string ) - return strftime ( format_string , self ) +function timetable_methods:strftime(format_string) + return strftime(format_string, self) end local timetable_mt -local function coerce_arg ( t ) - if getmetatable ( t ) == timetable_mt then - return t:timestamp ( ) +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 a:timestamp ( ) == b:timestamp ( ) - end ; - __lt = function ( a , b ) - return a:timestamp ( ) < b:timestamp ( ) - end ; - __sub = function ( a , b ) - return coerce_arg ( a ) - coerce_arg ( b ) - end ; + __index = timetable_methods; + __tostring = timetable_methods.rfc_3339; + __eq = function(a, b) + return a:timestamp() == b:timestamp() + end; + __lt = function(a, b) + return a:timestamp() < b:timestamp() + end; + __sub = function(a, b) + return coerce_arg(a) - coerce_arg(b) + end; } -local function cast_timetable ( tm ) - return setmetatable ( tm , timetable_mt ) +local function cast_timetable(tm) + return setmetatable(tm, timetable_mt) end -local function new_timetable ( year , month , day , hour , min , sec , yday , wday ) +local function new_timetable(year, month, day, hour, min, sec, yday, wday) return cast_timetable { - year = year ; - month = month ; - day = day ; - hour = hour ; - min = min ; - sec = sec ; - yday = yday ; - wday = wday ; + year = year; + month = month; + day = day; + hour = hour; + min = min; + sec = sec; + yday = yday; + wday = wday; } end -function timetable_methods:clone ( ) - return new_timetable ( self:unpack ( ) ) +function timetable_methods:clone() + return new_timetable(self:unpack()) 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 ) +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 ):normalise ( ) + return new_timetable(1970, 1, 1, 0, 0, ts):normalise() end return { - is_leap = is_leap ; - day_of_year = day_of_year ; - day_of_week = day_of_week ; - normalise = normalise ; - timestamp = timestamp ; - - new = new_timetable ; - new_from_timestamp = new_from_timestamp ; - cast = cast_timetable ; - timetable_mt = timetable_mt ; + is_leap = is_leap; + day_of_year = day_of_year; + day_of_week = day_of_week; + normalise = normalise; + timestamp = timestamp; + + new = new_timetable; + new_from_timestamp = new_from_timestamp; + cast = cast_timetable; + timetable_mt = timetable_mt; }