files/lua/date.lua
--[[LuaDate version:2.0.1]]-------------------------------
--[[------------------------------------------------------
	Copyright (C) 2006, by Jas Latrix (jastejada@yahoo.com)
	All Rights Deserved.
	use this code at your own risk!.
	keep out of reach of children.
--]]------------------------------------------------------
--[[ CONSTANTS ]]--
	local HOURPERDAY  = 24
	local MINPERHOUR  = 60
	local MINPERDAY	  = 1440  -- 24*60
	local SECPERMIN   = 60
	local SECPERHOUR  = 3600  -- 60*60
	local SECPERDAY   = 86400 -- 24*60*60
	local TICKSPERSEC = 1000000
	local TICKSPERDAY = 86400000000
	local TICKSPERHOUR = 3600000000
	local TICKSPERMIN = 60000000
	local DAYNUM_MAX =  365242500 -- Sat Jan 01 1000000 00:00:00
	local DAYNUM_MIN = -365242500 -- Mon Jan 01 1000000 BCE 00:00:00
	local DAYNUM_DEF =  0 -- Mon Jan 01 0001 00:00:00
	local _;
--[[ LOCAL ARE FASTER ]]--
	local type     = type
	local pairs    = pairs
	local error    = error
	local assert   = assert
	local tonumber = tonumber
	local tostring = tostring
	local string   = string
	local math     = math
	local os       = os
	local unpack   = unpack
	local setmetatable = setmetatable
	local getmetatable = getmetatable
--[[ EXTRA FUNCTIONS ]]--
	local fmt  = string.format
	local lwr  = string.lower
	local upr  = string.upper
	local rep  = string.rep
	local len  = string.len
	local sub  = string.sub
	local gsub = string.gsub
	local gmatch = string.gmatch or string.gfind
 	local find = string.find
	local ostime = os.time
	local osdate = os.date
	local floor = math.floor
	local ceil  = math.ceil
	local abs   = math.abs
	-- removes the decimal part of a number
	local function fix(n) n = tonumber(n) return n and ((n > 0 and floor or ceil)(n)) end
	-- returns the modulo n % d;
	local function mod (n,d) return n - d*floor(n/d) end
	-- rounds a number;
	local function round(n, d) d=d^10 return floor((n*d)+.5)/d end
	-- rounds a number to whole;
	local function whole(n)return floor(n+.5)end
	-- is `str` in string list `tbl`, `ml` is the minimun len
	local function inlist(str, tbl, ml, tn)
		local sl = len(str)
		if sl < (ml or 0) then return nil end
		str = lwr(str)
		for k, v in pairs(tbl) do
			if str == lwr(sub(v, 1, sl)) then
				if tn then tn[0] = k end
				return k
			end
		end
	end
	local function fnil() end
	local function fret(x)return x;end
--[[ DATE FUNCTIONS ]]--
	local DATE_EPOCH -- to be set later
	local sl_weekdays = {
		[0]="Sunday",[1]="Monday",[2]="Tuesday",[3]="Wednesday",[4]="Thursday",[5]="Friday",[6]="Saturday",
		[7]="Sun",[8]="Mon",[9]="Tue",[10]="Wed",[11]="Thu",[12]="Fri",[13]="Sat",
	}
	local sl_meridian = {[-1]="AM", [1]="PM"}
	local sl_months = {
		[00]="January", [01]="February", [02]="March",
		[03]="April",   [04]="May",      [05]="June",
		[06]="July",    [07]="August",   [08]="September",
		[09]="October", [10]="November", [11]="December",
		[12]="Jan", [13]="Feb", [14]="Mar",
		[15]="Apr", [16]="May", [17]="Jun",
		[18]="Jul", [19]="Aug", [20]="Sep",
		[21]="Oct", [22]="Nov", [23]="Dec",
	}
	-- added the '.2'  to avoid collision, use `fix` to remove
	local sl_timezone = {
		[000]="utc",	  [0.2]="gmt",
		[300]="est",	  [240]="edt",
		[360]="cst",	[300.2]="cdt",
		[420]="mst",	[360.2]="mdt",
		[480]="pst",	[420.2]="pdt",
	}
	-- set the day fraction resolution
	local function setticks(t)
		TICKSPERSEC = t;
		TICKSPERDAY = SECPERDAY*TICKSPERSEC
		TICKSPERHOUR= SECPERHOUR*TICKSPERSEC
		TICKSPERMIN = SECPERMIN*TICKSPERSEC
	end
	-- is year y leap year?
	local function isleapyear(y) -- y must be int!
		return (mod(y, 4) == 0 and (mod(y, 100) ~= 0 or mod(y, 400) == 0))
	end
	-- day since year 0
	local function dayfromyear(y) -- y must be int!
		return 365*y + floor(y/4) - floor(y/100) + floor(y/400)
	end
	-- day number from date, month is zero base
	local function makedaynum(y, m, d)
		local mm = mod(mod(m,12) + 10, 12)
		return dayfromyear(y + floor(m/12) - floor(mm/10)) + floor((mm*306 + 5)/10) + d - 307
		--local yy = y + floor(m/12) - floor(mm/10)
		--return dayfromyear(yy) + floor((mm*306 + 5)/10) + (d - 1)
	end
	-- date from day number, month is zero base
	local function breakdaynum(g)
		local g = g + 306
		local y = floor((10000*g + 14780)/3652425)
		local d = g - dayfromyear(y)
		if d < 0 then y = y - 1; d = g - dayfromyear(y) end
		local mi = floor((100*d + 52)/3060)
		return (floor((mi + 2)/12) + y), mod(mi + 2,12), (d - floor((mi*306 + 5)/10) + 1)
	end
	--[[ for floats or int32 Lua Number data type
	local function breakdaynum2(g)
		local g, n = g + 306;
		local n400 = floor(g/DI400Y);n = mod(g,DI400Y);
		local n100 = floor(n/DI100Y);n = mod(n,DI100Y);
		local n004 = floor(n/DI4Y);	 n = mod(n,DI4Y);
		local n001 = floor(n/365);	 n = mod(n,365);
		local y = (n400*400) + (n100*100) + (n004*4) + n001	- ((n001 == 4 or n100 == 4) and 1 or 0)
		local d = g - dayfromyear(y)
		local mi = floor((100*d + 52)/3060)
		return (floor((mi + 2)/12) + y), mod(mi + 2,12), (d - floor((mi*306 + 5)/10) + 1)		
	end
	]]		
	-- day fraction from time
	local function makedayfrc(h,r,s,t)
		return ((h*60 + r)*60 + s)*TICKSPERSEC + t
	end
	-- time from day fraction
	local function breakdayfrc(df)
		return
			mod(floor(df/TICKSPERHOUR),HOURPERDAY),
			mod(floor(df/TICKSPERMIN ),MINPERHOUR),
			mod(floor(df/TICKSPERSEC ),SECPERMIN),
			mod(df,TICKSPERSEC)
	end
	-- weekday sunday = 0, monday = 1 ...
	local function weekday(dn) return mod(dn + 1, 7) end
	-- yearday 0 based ...
	local function yearday(dn)
 		return dn - dayfromyear((breakdaynum(dn))-1)
	end
	-- parse v as a month
	local function getmontharg(v)
		local m = tonumber(v);
		return (m and fix(m - 1)) or inlist(tostring(v) or "", sl_months, 2)
	end
	-- get daynum of isoweek one of year y
	local function isow1(y)
		local f = makedaynum(y, 0, 4) -- get the date for the 4-Jan of year `y`
		local d = weekday(f)
		d = d == 0 and 7 or d -- get the ISO day number, 1 == Monday, 7 == Sunday
		return f + (1 - d)
	end
	local function isowy(dn)
		local w1;
		local y = (breakdaynum(dn))
		if dn >= makedaynum(y, 11, 29) then
			w1 = isow1(y + 1);
			if dn < w1 then
				w1 = isow1(y);
			else
			  	y = y + 1;
			end
		else
			w1 = isow1(y);
			if dn < w1 then
				w1 = isow1(y-1)
				y = y - 1
			end
		end
		return floor((dn-w1)/7)+1, y
	end
	local function isoy(dn)
		local y = (breakdaynum(dn))
		return y + (((dn >= makedaynum(y, 11, 29)) and (dn >= isow1(y + 1))) and 1 or (dn < isow1(y) and -1 or 0))
	end
	local function makedaynum_isoywd(y,w,d)
		return isow1(y) + 7*w + d - 8 -- simplified: isow1(y) + ((w-1)*7) + (d-1)
	end
--[[ THE DATE MOUDLE ]]--
	local fmtstr  = "%x %X";
--#if not DATE_OBJECT_AFX then
	date = {}
	local date = date
	setmetatable(date, date)
-- Version:  VMMMRRRR; V-Major, M-Minor, R-Revision;  e.g. 5.45.321 == 50450321
	date.version = 20000000 -- 2.0.0
--#end -- not DATE_OBJECT_AFX
--[[ THE DATE OBJECT ]]--
	local dobj = {}
	dobj.__index = dobj
	dobj.__metatable = dobj
	-- shout invalid arg
	local function date_error_arg() return error("invalid argument(s)",0) end
	-- create new date object
	local function date_new(dn, df)
		return setmetatable({daynum=dn, dayfrc=df}, dobj)
	end
	-- is `v` a date object?
	local function date_isdobj(v)
		return (type(v) == 'table' and getmetatable(v) == dobj) and v
	end

--#if not NO_LOCAL_TIME_SUPPORT then
	-- magic year table
	local date_epoch, yt;
	local function getequivyear(y)
		assert(not yt)
		yt = {}
		local de, dw, dy = date_epoch:copy()
		for i = 0, 3000 do
			de:setyear(de:getyear() + 1, 1, 1)
			dy = de:getyear()
			dw = de:getweekday() * (isleapyear(dy) and  -1 or 1)
			if not yt[dw] then yt[dw] = dy end  --print(de)
			if yt[1] and yt[2] and yt[3] and yt[4] and yt[5] and yt[6] and yt[7] and yt[-1] and yt[-2] and yt[-3] and yt[-4] and yt[-5] and yt[-6] and yt[-7] then
				getequivyear = function(y)	return yt[ (weekday(makedaynum(y, 0, 1)) + 1) * (isleapyear(y) and  -1 or 1) ]	end
				return getequivyear(y)
			end
		end
	end
	-- TimeValue from daynum and dayfrc
	local function dvtotv(dn, df)
		return fix(dn - DATE_EPOCH) * SECPERDAY  + (df/1000)
	end
	-- TimeValue from date and time
	local function totv(y,m,d,h,r,s)
		return (makedaynum(y, m, d) - DATE_EPOCH) * SECPERDAY  + ((h*60 + r)*60 + s)
	end
	-- TimeValue from TimeTable
	local function tmtotv(tm)
		return tm and totv(tm.year, tm.month - 1, tm.day, tm.hour, tm.min, tm.sec)
	end
	-- Returns the bias in seconds of utc time daynum and dayfrc
	local function getbiasutc2(self)
		local y,m,d = breakdaynum(self.daynum)
		local h,r,s = breakdayfrc(self.dayfrc)
		local tvu = totv(y,m,d,h,r,s) -- get the utc TimeValue of date and time
		local tml = osdate("*t", tvu) -- get the local TimeTable of tvu
		if (not tml) or (tml.year > (y+1) or tml.year < (y-1)) then -- failed try the magic
			y = getequivyear(y)
			tvu = totv(y,m,d,h,r,s)
			tml = osdate("*t", tvu)
		end
		local tvl = tmtotv(tml)
		if tvu and tvl then
			return tvu - tvl, tvu, tvl
		else
			return error("failed to get bias from utc time")
		end
	end
	-- Returns the bias in seconds of local time daynum and dayfrc
	local function getbiasloc2(daynum, dayfrc)
		local tvu
		-- extract date and time
		local y,m,d = breakdaynum(daynum)
		local h,r,s = breakdayfrc(dayfrc)
		-- get equivalent TimeTable
		local tml = {year=y, month=m+1, day=d, hour=h, min=r, sec=s}
		-- get equivalent TimeValue
		local tvl = tmtotv(tml)

		local function chkutc()
			tml.isdst =  nil; local tvug = ostime(tml) if tvug and (tvl == tmtotv(osdate("*t", tvug))) then tvu = tvug return end
			tml.isdst = true; local tvud = ostime(tml) if tvud and (tvl == tmtotv(osdate("*t", tvud))) then tvu = tvud return end
			tvu = tvud or tvug
		end
		chkutc()
		if not tvu then
			tml.year = getequivyear(y)
			tvl = tmtotv(tml)
			chkutc()
		end
		return ((tvu and tvl) and (tvu - tvl)) or error("failed to get bias from local time"), tvu, tvl
	end
--#end -- not NO_LOCAL_TIME_SUPPORT

--#if not DATE_OBJECT_AFX then
	-- the date parser
	local strwalker = {} -- ^Lua regular expression is not as powerful as Perl$
	strwalker.__index = strwalker
	local function newstrwalker(s)return setmetatable({s=s, i=1, e=1, c=len(s)}, strwalker) end
	function strwalker:aimchr() return "\n" .. self.s .. "\n" .. rep(".",self.e-1) .. "^" end
	function strwalker:finish() return self.i > self.c	end
	function strwalker:back()	self.i = self.e return self	end
	function strwalker:restart() self.i, self.e = 1, 1 return self end
	function strwalker:match(s)	return (find(self.s, s, self.i)) end
	function strwalker:__call(s, f)-- print("strwalker:__call "..s..self:aimchr())
		local is, ie; is, ie, self[1], self[2], self[3], self[4], self[5] = find(self.s, s, self.i)
		if is then self.e, self.i = self.i, 1+ie; if f then f(unpack(self)) end return self end
	end
 	local function date_parse(str)
		local y,m,d, h,r,s,	z,	w,u, j,	e,	k,	x,v,c,	chkfin,	dn,df;
		local sw = newstrwalker(gsub(gsub(str, "(%b())", ""),"^(%s*)","")) -- remove comment, trim leading space
		--local function error_out() print(y,m,d,h,r,s) end
		local function error_dup(q) --[[error_out()]] error("duplicate value: " .. (q or "") .. sw:aimchr()) end
		local function error_syn(q) --[[error_out()]] error("syntax error: " .. (q or "") .. sw:aimchr()) end
		local function error_inv(q) --[[error_out()]] error("invalid date: " .. (q or "") .. sw:aimchr()) end
		local function sety(q) y = y and error_dup() or tonumber(q); end
		local function setm(q) m = (m or w or j) and error_dup(m or w or j) or tonumber(q) end
		local function setd(q) d = d and error_dup() or tonumber(q) end
		local function seth(q) h = h and error_dup() or tonumber(q) end
		local function setr(q) r = r and error_dup() or tonumber(q) end
		local function sets(q) s = s and error_dup() or tonumber(q) end
		local function adds(q) s = s + tonumber(q) end
		local function setj(q) j = (m or w or j) and error_dup() or tonumber(q); end
		local function setz(q) z = (z ~= 0 and z) and error_dup() or q end
		local function setzn(zs,zn) zn = tonumber(zn); setz( ((zn<24) and (zn*60) or (mod(zn,100) + floor(zn/100) * 60))*( zs=='+' and -1 or 1) ) end
		local function setzc(zs,zh,zm) setz( ((tonumber(zh)*60) + tonumber(zm))*( zs=='+' and -1 or 1) ) end

		if not (sw("^(%d%d%d%d)",sety) and (sw("^(%-?)(%d%d)%1(%d%d)",function(_,a,b) setm(tonumber(a)); setd(tonumber(b)) end) or sw("^(%-?)[Ww](%d%d)%1(%d?)",function(_,a,b) w, u = tonumber(a), tonumber(b or 1) end) or sw("^%-?(%d%d%d)",setj) or sw("^%-?(%d%d)",function(a) setm(a);setd(1) end))
		and ((sw("^%s*[Tt]?(%d%d):?",seth) and sw("^(%d%d):?",setr) and sw("^(%d%d)",sets) and sw("^(%.%d+)",adds))
			or sw:finish() or (sw"^%s*$" or sw"^%s*[Zz]%s*$" or sw("^%s-([%+%-])(%d%d):?(%d%d)%s*$",setzc) or sw("^%s*([%+%-])(%d%d)%s*$",setzn))
			)	)
		then --print(y,m,d,h,r,s,z,w,u,j)
		sw:restart(); y,m,d,h,r,s,z,w,u,j = nil;
			repeat -- print(sw:aimchr())
				if sw("^[tT:]?%s*(%d%d?):",seth) then --print("$Time")
					_ = sw("^%s*(%d%d?)",setr) and sw("^%s*:%s*(%d%d?)",sets) and sw("^(%.%d+)",adds)
				elseif sw("^(%d+)[/\%s,-]?%s*") then --print("$Digits")
					x, c = tonumber(sw[1]), len(sw[1])
					if (x >= 70) or (m and d and (not y)) or (c > 3) then
						sety( x + ((x >= 100 or c>3)and 0 or 1900) )
					else
						if m then setd(x) else m = x end
					end
				elseif sw("^(%a+)[/\%s,-]?%s*") then --print("$Words")
					x = sw[1]
					if inlist(x, sl_months,   2, sw) then
						if m and (not d) and (not y) then d, m = m, false end
						setm(mod(sw[0],12)+1)
					elseif inlist(x, sl_timezone, 2, sw) then
						c = fix(sw[0]) -- ignore gmt and utc
						if c ~= 0 then setz(c, x) end
					elseif inlist(x, sl_weekdays, 2, sw) then
						k = sw[0]
					else
						sw:back()
						-- am pm bce ad ce bc
						if sw ("^([bB])%s*(%.?)%s*[Cc]%s*(%2)%s*[Ee]%s*(%2)%s*") or sw ("^([bB])%s*(%.?)%s*[Cc]%s*(%2)%s*") then
							e = e and error_dup() or -1
						elseif sw ("^([aA])%s*(%.?)%s*[Dd]%s*(%2)%s*") or sw ("^([cC])%s*(%.?)%s*[Ee]%s*(%2)%s*") then
							e = e and error_dup() or 1
						elseif sw("^([PApa])%s*(%.?)%s*[Mm]?%s*(%2)%s*") then
							x = lwr(sw[1]) -- there should be hour and it must be correct
							if (not h) or (h > 12) or (h < 0) then return error_inv() end
							if x == 'a' and h == 12 then h = 0 end -- am
							if x == 'p' and h ~= 12 then h = h + 12 end -- pm
						else error_syn() end
					end
				elseif not(sw("^([+-])(%d%d?):(%d%d)",setzc) or sw("^([+-])(%d+)",setzn) or sw("^[Zz]%s*$")) then -- sw{"([+-])",{"(%d%d?):(%d%d)","(%d+)"}}
					error_syn("?")
				end
			sw("^%s*")	until sw:finish()
		--else print("$Iso(Date|Time|Zone)")
		end
		-- if date is given, it must be complete year, month & day
		if (not y and not h) or ((m and not d) or (d and not m)) or ((m and w) or (m and j) or (j and w)) then return error_inv("!") end
		-- fix month
		if m then m = m - 1 end
		-- fix year if we are on BCE
		if e and e < 0 and y > 0 then y = 1 - y end
		--  create date object
		dn = (y and ((w and makedaynum_isoywd(y,w,u)) or (j and makedaynum(y, 0, j)) or makedaynum(y, m, d))) or DAYNUM_DEF
		df = makedayfrc(h or 0, r or 0, s or 0, 0) + ((z or 0)*TICKSPERMIN)
		--print("Zone",h,r,s,z,m,d,y,df)
		return date_new(dn, df) -- no need to :normalize();
 	end
	local function date_fromtable(v)
		local y, m, d = fix(v.year), getmontharg(v.month), fix(v.day)
		local h, r, s, t = tonumber(v.hour), tonumber(v.min), tonumber(v.sec), tonumber(v.ticks)
		-- atleast there is time or complete date
		if (y or m or d) and (not(y and m and d)) then return error("incomplete table")	end
		return (y or h or r or s or t) and date_new(y and makedaynum(y, m, d) or DAYNUM_DEF, makedayfrc(h or 0, r or 0, s or 0, t or 0))
	end
	local tmap = {
		['number'] = function(v) return date_epoch:copy():addseconds(v) end,
		['string'] = function(v) return date_parse(v) end,
		['boolean']= function(v) return date_fromtable(osdate(v and "!*t" or "*t")) end,
		['table']  = function(v) local ref = getmetatable(v) == dobj; return ref and v or date_fromtable(v), ref end
	}
	local function date_getdobj(v)
		local o, r = (tmap[type(v)] or fnil)(v);
		return (o and o:normalize() or error"invalid date time value"), r -- if r is true then o is a reference to a date obj
	end
--#end -- not DATE_OBJECT_AFX
 	local function date_from(...)
 		local y, m, d = fix(arg[1]), getmontharg(arg[2]), fix(arg[3])
		local h, r, s, t = tonumber(arg[4] or 0), tonumber(arg[5] or 0), tonumber(arg[6] or 0), tonumber(arg[7] or 0)
		if y and m and d and h and r and s and t then
			return date_new(makedaynum(y, m, d), makedayfrc(h, r, s, t)):normalize()
		else
			return date_error_arg()
		end
	end

 --[[ THE DATE OBJECT METHODS ]]--
	function dobj:normalize()
		local dn, df = fix(self.daynum), self.dayfrc
		self.daynum, self.dayfrc = dn + floor(df/TICKSPERDAY), mod(df, TICKSPERDAY)
		return (dn >= DAYNUM_MIN and dn <= DAYNUM_MAX) and self or error("date beyond imposed limits:"..self)
	end

	function dobj:getdate()	local y, m, d = breakdaynum(self.daynum) return y, m+1, d end
	function dobj:gettime()	return breakdayfrc(self.dayfrc) end

	function dobj:getclockhour() local h = self:gethours() return h>12 and mod(h,12) or (h==0 and 12 or h) end

	function dobj:getyearday() return yearday(self.daynum) + 1 end
	function dobj:getweekday() return weekday(self.daynum) + 1 end   -- in lua weekday is sunday = 1, monday = 2 ...

	function dobj:getyear()	 local r,_,_ = breakdaynum(self.daynum)	return r end
	function dobj:getmonth() local _,r,_ = breakdaynum(self.daynum)	return r+1 end-- in lua month is 1 base
	function dobj:getday()	 local _,_,r = breakdaynum(self.daynum)	return r end
	function dobj:gethours()	return mod(floor(self.dayfrc/TICKSPERHOUR),HOURPERDAY) end
	function dobj:getminutes()	return mod(floor(self.dayfrc/TICKSPERMIN), MINPERHOUR) end
	function dobj:getseconds()	return mod(floor(self.dayfrc/TICKSPERSEC ),SECPERMIN)  end
	function dobj:getfracsec()	return mod(floor(self.dayfrc/TICKSPERSEC ),SECPERMIN)+(mod(self.dayfrc,TICKSPERSEC)/TICKSPERSEC) end
	function dobj:getticks(u)	local x = mod(self.dayfrc,TICKSPERSEC) return u and ((x*u)/TICKSPERSEC) or x  end

	function dobj:getweeknumber(wdb)
		local wd, yd = weekday(self.daynum), yearday(self.daynum)
		if wdb then
			wdb = tonumber(wdb)
			if wdb then
				wd = mod(wd-(wdb-1),7)-- shift the week day base
			else
				return date_error_arg()
			end
		end
		return (yd < wd and 0) or (floor(yd/7) + ((mod(yd, 7)>=wd) and 1 or 0))
	end

	function dobj:getisoweekday() return mod(weekday(self.daynum)-1,7)+1 end   -- sunday = 7, monday = 1 ...
 	function dobj:getisoweeknumber() return (isowy(self.daynum)) end
 	function dobj:getisoyear() return isoy(self.daynum)	end
 	function dobj:getisodate()
 		local w, y = isowy(self.daynum)
		return y, w, self:getisoweekday()
	end
 	function dobj:setisoyear(y, w, d)
		local cy, cw, cd = self:getisodate()
		if y then cy = fix(tonumber(y))end
		if w then cw = fix(tonumber(w))end
		if d then cd = fix(tonumber(d))end
		if cy and cw and cd then
			self.daynum = makedaynum_isoywd(cy, cw, cd)
			return self:normalize()
		else
			return date_error_arg()
		end
	end

	function dobj:setisoweekday(d)		return self:setisoyear(nil, nil, d) end
 	function dobj:setisoweeknumber(w,d)	return self:setisoyear(nil, w, d)	end

	function dobj:setyear(y, m, d)
		local cy, cm, cd = breakdaynum(self.daynum)
		if y then cy = fix(tonumber(y))end
		if m then cm = getmontharg(m)  end
		if d then cd = fix(tonumber(d))end
		if cy and cm and cd then
			self.daynum  = makedaynum(cy, cm, cd)
			return self:normalize()
		else
			return date_error_arg()
		end
	end

	function dobj:setmonth(m, d)return self:setyear(nil, m, d) end
	function dobj:setday(d)		return self:setyear(nil, nil, d) end

	function dobj:sethours(h, m, s, t)
		local ch,cm,cs,ck = breakdayfrc(self.dayfrc)
		ch, cm, cs, ck = tonumber(h or ch), tonumber(m or cm), tonumber(s or cs), tonumber(t or ck)
		if ch and cm and cs and ck then
			self.dayfrc = makedayfrc(ch, cm, cs, ck)
			return self:normalize()
		else
			return date_error_arg()
		end
	end

	function dobj:setminutes(m,s,t)	return self:sethours(nil,   m,   s, t) end
	function dobj:setseconds(s, t)	return self:sethours(nil, nil,   s, t) end
	function dobj:setticks(t)		return self:sethours(nil, nil, nil, t) end

	function dobj:spanticks()	return (self.daynum*TICKSPERDAY + self.dayfrc) end
	function dobj:spanseconds()	return (self.daynum*TICKSPERDAY + self.dayfrc)/TICKSPERSEC  end
	function dobj:spanminutes()	return (self.daynum*TICKSPERDAY + self.dayfrc)/TICKSPERMIN  end
	function dobj:spanhours()	return (self.daynum*TICKSPERDAY + self.dayfrc)/TICKSPERHOUR end
	function dobj:spandays()	return (self.daynum*TICKSPERDAY + self.dayfrc)/TICKSPERDAY  end

	function dobj:addyears(y, m, d)
		local cy, cm, cd = breakdaynum(self.daynum)
		if y then y = fix(tonumber(y))else y = 0 end
		if m then m = fix(tonumber(m))else m = 0 end
		if d then d = fix(tonumber(d))else d = 0 end
		if y and m and d then
			self.daynum  = makedaynum(cy+y, cm+m, cd+d)
			return self:normalize()
		else
			return date_error_arg()
		end
	end

	function dobj:addmonths(m, d)
		return self:addyears(nil, m, d)
	end

	local function dobj_adddayfrc(self,n,pt,pd)
		n = tonumber(n)
		if n then
			local x = floor(n/pd);
			self.daynum = self.daynum + x;
			self.dayfrc = self.dayfrc + (n-x*pd)*pt;
			return self:normalize()
		else
			return date_error_arg()
		end
	end
 	function dobj:adddays(n)	return dobj_adddayfrc(self,n,TICKSPERDAY,1) end
	function dobj:addhours(n)	return dobj_adddayfrc(self,n,TICKSPERHOUR,HOURPERDAY) end
	function dobj:addminutes(n)	return dobj_adddayfrc(self,n,TICKSPERMIN,MINPERDAY)  end
	function dobj:addseconds(n)	return dobj_adddayfrc(self,n,TICKSPERSEC,SECPERDAY)  end
 	function dobj:addticks(n)	return dobj_adddayfrc(self,n,1,TICKSPERDAY) end
	local tvspec = {
		-- Abbreviated weekday name (Sun)
		['%a']=function(self) return sl_weekdays[weekday(self.daynum) + 7] end,
		-- Full weekday name (Sunday)
		['%A']=function(self) return sl_weekdays[weekday(self.daynum)] end,
		-- Abbreviated month name (Dec)
		['%b']=function(self) return sl_months[self:getmonth() - 1 + 12] end,
		-- Full month name (December)
		['%B']=function(self) return sl_months[self:getmonth() - 1] end,
		-- Year/100 (19, 20, 30)
		['%C']=function(self) return fmt("%.2d", fix(self:getyear()/100)) end,
		-- The day of the month as a number (range 1 - 31)
		['%d']=function(self) return fmt("%.2d", self:getday())  end,
		-- year for ISO 8601 week, from 00 (79)
		['%g']=function(self) return fmt("%.2d", mod(self:getisoyear() ,100)) end,
		-- year for ISO 8601 week, from 0000 (1979)
		['%G']=function(self) return fmt("%.4d", self:getisoyear()) end,
		-- same as %b
		['%h']=function(self) return self:fmt0("%b") end,
		-- hour of the 24-hour day, from 00 (06)
		['%H']=function(self) return fmt("%.2d", self:gethours()) end,
		-- The  hour as a number using a 12-hour clock (01 - 12)
		['%I']=function(self) return fmt("%.2d", self:getclockhour()) end,
		-- The day of the year as a number (001 - 366)
		['%j']=function(self) return fmt("%.3d", self:getyearday())  end,
		-- Month of the year, from 01 to 12
		['%m']=function(self) return fmt("%.2d", self:getmonth())  end,
		-- Minutes after the hour 55
		['%M']=function(self) return fmt("%.2d", self:getminutes())end,
		-- AM/PM indicator (AM)
		['%p']=function(self) return sl_meridian[self:gethours() > 11 and 1 or -1] end, --AM/PM indicator (AM)
		-- The second as a number (59, 20 , 01)
		['%S']=function(self) return fmt("%.2d", self:getseconds())  end,
		-- ISO 8601 day of the week, to 7 for Sunday (7, 1)
		['%u']=function(self) return self:getisoweekday() end,
		-- Sunday week of the year, from 00 (48)
		['%U']=function(self) return fmt("%.2d", self:getweeknumber()) end,
		-- ISO 8601 week of the year, from 01 (48)
		['%V']=function(self) return fmt("%.2d", self:getisoweeknumber()) end,
		-- The day of the week as a decimal, Sunday being 0
		['%w']=function(self) return self:getweekday() - 1 end,
		-- Monday week of the year, from 00 (48)
		['%W']=function(self) return fmt("%.2d", self:getweeknumber(2)) end,
		-- The year as a number without a century (range 00 to 99)
		['%y']=function(self) return fmt("%.2d", mod(self:getyear() ,100)) end,
		-- Year with century (2000, 1914, 0325, 0001)
		['%Y']=function(self) return fmt("%.4d", self:getyear()) end,
		-- Time zone offset, the date object is assumed local time (+1000, -0230)
		['%z']=function(self) local b = -self:getbias(); local x = abs(b); return fmt("%s%.4d", b < 0 and "-" or "+", fix(x/60)*100 + floor(mod(x,60))) end,
		-- Time zone name, the date object is assumed local time
		['%Z']=function(self) return self:gettzname() end,
		-- Misc --
		-- Year, if year is in BCE, prints the BCE Year representation, otherwise result is similar to "%Y" (1 BCE, 40 BCE)
		['%\b']=function(self) local x = self:getyear() return fmt("%.4d%s", x>0 and x or (-x+1), x>0 and "" or " BCE") end,
		-- Seconds including fraction (59.998, 01.123)
		['%\f']=function(self) local x = self:getfracsec() return fmt("%s%.9g",x >= 10 and "" or "0", x) end,
		-- percent character %
		['%%']=function(self) return "%" end,
		-- Group Spec --
		-- 12-hour time, from 01:00:00 AM (06:55:15 AM); same as "%I:%M:%S %p"
		['%r']=function(self) return self:fmt0("%I:%M:%S %p") end,
		-- hour:minute, from 01:00 (06:55); same as "%I:%M"
		['%R']=function(self) return self:fmt0("%I:%M")  end,
		-- 24-hour time, from 00:00:00 (06:55:15); same as "%H:%M:%S"
		['%T']=function(self) return self:fmt0("%H:%M:%S") end,
		-- month/day/year from 01/01/00 (12/02/79); same as "%m/%d/%y"
		['%D']=function(self) return self:fmt0("%m/%d/%y") end,
		-- year-month-day (1979-12-02); same as "%Y-%m-%d"
		['%F']=function(self) return self:fmt0("%Y-%m-%d") end,
		-- The preferred date and time representation;  same as "%x %X"
		['%c']=function(self) return self:fmt0("%x %X") end,
		-- The preferred date representation, same as "%a %b %d %\b"
		['%x']=function(self) return self:fmt0("%a %b %d %\b") end,
		-- The preferred time representation, same as "%H:%M:%\f"
		['%X']=function(self) return self:fmt0("%H:%M:%\f") end,
		-- GroupSpec --
		-- Iso format, same as "%Y-%m-%dT%T"
		['${iso}'] = function(self) return self:fmt0("%Y-%m-%dT%T") end,
		-- http format, same as "%a, %d %b %Y %T GMT"
		['${http}'] = function(self) return self:fmt0("%a, %d %b %Y %T GMT") end,
		-- ctime format, same as "%a %b %d %T GMT %Y"
		['${ctime}'] = function(self) return self:fmt0("%a %b %d %T GMT %Y") end,
		-- RFC850 format, same as "%A, %d-%b-%y %T GMT"
		['${rfc850}'] = function(self) return self:fmt0("%A, %d-%b-%y %T GMT") end,
		-- RFC1123 format, same as "%a, %d %b %Y %T GMT"
		['${rfc1123}'] = function(self) return self:fmt0("%a, %d %b %Y %T GMT") end,
		-- asctime format, same as "%a %b %d %T %Y"
		['${asctime}'] = function(self) return self:fmt0("%a %b %d %T %Y") end,
	}
	function dobj:fmt0(str) return (gsub(str, "%%[%a%%\b\f]", function(x) local f = tvspec[x];return (f and f(self)) or x end)) end
	function dobj:fmt(str)
		str = str or self.fmtstr or fmtstr
		return self:fmt0((gmatch(str, "${%w+}")) and (gsub(str, "${%w+}", function(x)local f=tvspec[x];return (f and f(self)) or x end)) or str)
	end

	function dobj.__lt(a,b)	return (a.daynum == b.daynum) and (a.dayfrc < b.dayfrc) or (a.daynum < b.daynum)	end
	function dobj.__le(a, b)return (a.daynum == b.daynum) and (a.dayfrc <= b.dayfrc) or (a.daynum <= b.daynum)	end
	function dobj.__eq(a, b)return (a.daynum == b.daynum) and (a.dayfrc == b.dayfrc) end
	function dobj.__sub(a,b)
		local d1, d2 = date_getdobj(a), date_getdobj(b)
		local d0 = d1 and d2 and date_new(d1.daynum - d2.daynum, d1.dayfrc - d2.dayfrc)
		return d0 and d0:normalize()
	end
	function dobj.__add(a,b)
		local d1, d2 = date_getdobj(a), date_getdobj(b)
		local d0 = d1 and d2 and date_new(d1.daynum + d2.daynum, d1.dayfrc + d2.dayfrc)
		return d0 and d0:normalize()
	end
	function dobj.__concat(a, b) return tostring(a) .. tostring(b) end
	function dobj:__tostring() return self:fmt() end

	function dobj:copy() return date_new(self.daynum, self.dayfrc) end

 --[[ THE LOCAL DATE OBJECT METHODS ]]--
 	function dobj:tolocal()
 		local dn,df = self.daynum, self.dayfrc
		local bias  = getbiasutc2(self)
		if bias then
			-- utc = local + bias; local = utc - bias
			self.daynum = dn
			self.dayfrc = df - bias*TICKSPERSEC
			return self:normalize()
		else
			return nil
		end
	end

	function dobj:toutc()
 		local dn,df = self.daynum, self.dayfrc
		local bias  = getbiasloc2(dn, df)
		if bias then
			-- utc = local + bias;
			self.daynum = dn
			self.dayfrc = df + bias*TICKSPERSEC
			return self:normalize()
		else
			return nil
		end
	end

	function dobj:getbias()	return (getbiasloc2(self.daynum, self.dayfrc))/SECPERMIN end

	function dobj:gettzname()
		local _, tvu, _ = getbiasloc2(self.daynum, self.dayfrc)
		return tvu and osdate("%Z",tvu) or ""
	end

--#if not DATE_OBJECT_AFX then
 	function date.time(h, r, s, t)
 		h, r, s, t = tonumber(h or 0), tonumber(r or 0), tonumber(s or 0), tonumber(t or 0)
 		if h and r and s and t then
 			return date_new(DAYNUM_DEF, makedayfrc(h, r, s, t))
		else
			return date_error_arg()
		end
 	end

	function date:__call(...)
		local n = arg.n
		if n  > 1 then return (date_from(unpack(arg)))
		elseif n == 0 then return (date_getdobj(false))
		else local o, r = date_getdobj(arg[1]);	return r and o:copy() or o end
	end

	date.diff = dobj.__sub

	function date.isleapyear(v)
		local y = fix(v);
		if not y then
			y = date_getdobj(v)
			y = y and y:getyear()
		end
		return isleapyear(y+0)
	end

	function date.epoch() return date_epoch:copy()	end

	function date.isodate(y,w,d) return date_new(makedaynum_isoywd(y + 0, w and (w+0) or 1, d and (d+0) or 1), 0)	end

-- Internal functions
	function date.fmt(str) if str then fmtstr = str end; return fmtstr end
	function date.daynummin(n)	DAYNUM_MIN = (n and n < DAYNUM_MAX) and n or DAYNUM_MIN	return n and DAYNUM_MIN or date_new(DAYNUM_MIN, 0):normalize()end
 	function date.daynummax(n)	DAYNUM_MAX = (n and n > DAYNUM_MIN) and n or DAYNUM_MAX return n and DAYNUM_MAX or date_new(DAYNUM_MAX, 0):normalize()end
	function date.ticks(t) if t then setticks(t) end return TICKSPERSEC	end
--#end -- not DATE_OBJECT_AFX

	local tm = osdate("!*t", 0);
	if tm then
		date_epoch = date_new(makedaynum(tm.year, tm.month - 1, tm.day), makedayfrc(tm.hour, tm.min, tm.sec, 0))
		-- the distance from our epoch to os epoch in daynum
		DATE_EPOCH = date_epoch and date_epoch:spandays()
	else -- error will be raise only if called!
		date_epoch = setmetatable({},{__index = function() error("failed to get the epoch date") end})
	end

--#if not DATE_OBJECT_AFX then
return date
--#else
--$return date_from
--#end

