From: daurnimator <quae@daurnimator.com>
Date: Mon, 21 Jul 2014 04:41:08 +0000 (-0900)
Subject: Add strftime
X-Git-Url: https://git.madduck.net/etc/awesome.git/commitdiff_plain/85c40964551cb74c3d6ef6bf61a12fd79013389b?ds=sidebyside

Add strftime
---

diff --git a/luatz-scm-0.rockspec b/luatz-scm-0.rockspec
index ab6f212..6324360 100644
--- a/luatz-scm-0.rockspec
+++ b/luatz-scm-0.rockspec
@@ -27,6 +27,7 @@ build = {
 		["luatz.gettime"]   = "luatz/gettime.lua" ;
 		["luatz.parse"]     = "luatz/parse.lua" ;
 		["luatz.timetable"] = "luatz/timetable.lua" ;
+		["luatz.strftime"]  = "luatz/strftime.lua" ;
 		["luatz.tzcache"]   = "luatz/tzcache.lua" ;
 		["luatz.tzfile"]    = "luatz/tzfile.lua" ;
 		["luatz.tzinfo"]    = "luatz/tzinfo.lua" ;
diff --git a/luatz/init.lua b/luatz/init.lua
index b3ca99e..2660715 100644
--- a/luatz/init.lua
+++ b/luatz/init.lua
@@ -1,5 +1,6 @@
 local _M = {
 	parse = require "luatz.parse" ;
+	strftime = require "luatz.strftime" ;
 	timetable = require "luatz.timetable" ;
 }
 
diff --git a/luatz/strftime.lua b/luatz/strftime.lua
new file mode 100644
index 0000000..0f6a26f
--- /dev/null
+++ b/luatz/strftime.lua
@@ -0,0 +1,203 @@
+local strformat = string.format
+local floor = math.floor
+local function idiv ( n , d )
+	return floor ( n / d )
+end
+
+local c_locale = {
+	abday = { "Sun" , "Mon" , "Tue" , "Wed" , "Thu" , "Fri" , "Sat" } ;
+	day = { "Sunday" , "Monday" , "Tuesday" , "Wednesday" , "Thursday" , "Friday" , "Saturday" } ;
+	abmon = { "Jan" , "Feb" , "Mar" , "Apr" , "May" , "Jun" , "Jul" , "Aug" , "Sep" , "Oct" , "Nov" , "Dec" } ;
+	mon = { "January" , "February" , "March" , "April" , "May" , "June" , "July" , "August" , "September" , "October" , "November" , "December" } ;
+	am_pm = { "AM" , "PM" } ;
+}
+
+--- ISO-8601 week logic
+-- ISO 8601 weekday as number with Monday as 1 (1-7)
+local function iso_8601_weekday ( wday )
+	if wday == 1 then
+		return 7
+	else
+		return wday - 1
+	end
+end
+local iso_8601_week do
+	-- Years that have 53 weeks according to ISO-8601
+	local long_years = { }
+	for i, v in ipairs {
+		  4,   9,  15,  20,  26,  32,  37,  43,  48,  54,  60,  65,  71,  76,  82,
+		 88,  93,  99, 105, 111, 116, 122, 128, 133, 139, 144, 150, 156, 161, 167,
+		172, 178, 184, 189, 195, 201, 207, 212, 218, 224, 229, 235, 240, 246, 252,
+		257, 263, 268, 274, 280, 285, 291, 296, 303, 308, 314, 320, 325, 331, 336,
+		342, 348, 353, 359, 364, 370, 376, 381, 387, 392, 398
+	} do
+		long_years [ v ] = true
+	end
+	local function is_long_year ( year )
+		return long_years [ year % 400 ]
+	end
+	function iso_8601_week ( self )
+		local wday = iso_8601_weekday ( self.wday )
+		local n = self.yday - wday
+		local year = self.year
+		if n < -3 then
+			year = year - 1
+			if is_long_year ( year ) then
+				return year , 53 , wday
+			else
+				return year , 52 , wday
+			end
+		elseif n >= 361 and not is_long_year ( year ) then
+			return year + 1 , 1 , wday
+		else
+			return year , idiv ( n + 10 , 7 ) , wday
+		end
+	end
+end
+
+--- Specifiers
+local t = { }
+function t:a ( locale )
+	return "%s" , locale.abday [ self.wday ]
+end
+function t:A ( locale )
+	return "%s" , locale.day [ self.wday ]
+end
+function t:b ( locale )
+	return "%s" , locale.abmon [ self.month ]
+end
+function t:B ( locale )
+	return "%s" , locale.mon [ self.month ]
+end
+function t:c ( locale )
+	return "%.3s %.3s%3d %.2d:%.2d:%.2d %d" ,
+		locale.abday [ self.wday ] , locale.abmon [ self.month ] ,
+		self.day , self.hour , self.min , self.sec , self.year
+end
+-- Century
+function t:C ( )
+	return "%02d" , idiv ( self.year , 100 )
+end
+function t:d ( )
+	return "%02d" , self.day
+end
+-- Short MM/DD/YY date, equivalent to %m/%d/%y
+function t:D ( )
+	return "%02d/%02d/%02d" , self.month , self.day , self.year % 100
+end
+function t:e ( )
+	return "%2d" , self.day
+end
+-- Short YYYY-MM-DD date, equivalent to %Y-%m-%d
+function t:F ( )
+	return "%d-%02d-%02d" , self.year , self.month , self.day
+end
+-- Week-based year, last two digits (00-99)
+function t:g ( )
+	return "%02d" , iso_8601_week ( self ) % 100
+end
+-- Week-based year
+function t:G ( )
+	return "%d" , iso_8601_week ( self )
+end
+t.h = t.b
+function t:H ( )
+	return "%02d" , self.hour
+end
+function t:I ( )
+	return "%02d" , (self.hour-1) % 12 + 1
+end
+function t:j ( )
+	return "%03d" , self.yday
+end
+function t:m ( )
+	return "%02d" , self.month
+end
+function t:M ( )
+	return "%02d" , self.min
+end
+-- New-line character ('\n')
+function t:n ( )
+	return "\n"
+end
+function t:p ( locale )
+	return self.hour < 12 and locale.am_pm[1] or locale.am_pm[2]
+end
+-- TODO: should respect locale
+function t:r ( locale )
+	return "%02d:%02d:%02d %s" ,
+		(self.hour-1) % 12 + 1 , self.min , self.sec ,
+		self.hour < 12 and locale.am_pm[1] or locale.am_pm[2]
+end
+-- 24-hour HH:MM time, equivalent to %H:%M
+function t:R ( )
+	return "%02d:%02d" , self.hour , self.min
+end
+function t:s ( )
+	return "%d" , self:timestamp ( )
+end
+function t:S ( )
+	return "%02d" , self.sec
+end
+-- Horizontal-tab character ('\t')
+function t:t ( )
+	return "\t"
+end
+-- ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S
+function t:T ( )
+	return "%02d:%02d:%02d" , self.hour , self.min , self.sec
+end
+function t:u ( )
+	return "%d" , iso_8601_weekday ( self.wday )
+end
+-- Week number with the first Sunday as the first day of week one (00-53)
+function t:U ( )
+	return "%02d" , idiv ( self.yday - self.wday + 7 , 7 )
+end
+-- ISO 8601 week number (00-53)
+function t:V ( )
+	return "%02d" , select ( 2 , iso_8601_week ( self ) )
+end
+-- Weekday as a decimal number with Sunday as 0 (0-6)
+function t:w ( )
+	return "%d" , self.wday - 1
+end
+-- Week number with the first Monday as the first day of week one (00-53)
+function t:W ( )
+	return "%02d" , idiv ( self.yday - iso_8601_weekday ( self.wday ) + 7 , 7 )
+end
+-- TODO make t.x and t.X respect locale
+t.x = t.D
+t.X = t.T
+function t:y ( )
+	return "%02d" , self.year % 100
+end
+function t:Y ( )
+	return "%d" , self.year
+end
+-- TODO timezones
+function t:z ( )
+	return "+0000"
+end
+function t:Z ( )
+	return "GMT"
+end
+-- A literal '%' character.
+t["%"] = function ( self )
+	return "%%"
+end
+
+local function strftime ( format_string , timetable )
+	return ( string.gsub ( format_string , "%%([EO]?)(.)" , function ( locale_modifier , specifier )
+		local func = t [ specifier ]
+		if func then
+			return strformat ( func ( timetable , c_locale ) )
+		else
+			error ( "invalid conversation specifier '%"..locale_modifier..specifier.."'" , 3 )
+		end
+	end ) )
+end
+
+return {
+	strftime = strftime ;
+}
diff --git a/luatz/timetable.lua b/luatz/timetable.lua
index 3bb7689..6cded31 100644
--- a/luatz/timetable.lua
+++ b/luatz/timetable.lua
@@ -143,6 +143,15 @@ function timetable_methods:rfc_3339 ( )
 	return strformat ( "%04u-%02u-%02uT%02u:%02u:%06.3f" , self:unpack ( ) )
 end
 
+local strftime = require "luatz.strftime".strftime
+function timetable_methods:strftime ( format_string )
+	return strftime ( format_string , self )
+end
+
+function timetable_methods:asctime ( )
+	return self:strftime ( "%c\n" )
+end
+
 local timetable_mt = {
 	__index    = timetable_methods ;
 	__tostring = timetable_methods.rfc_3339 ;
diff --git a/spec/strftime_spec.lua b/spec/strftime_spec.lua
new file mode 100644
index 0000000..6d019c9
--- /dev/null
+++ b/spec/strftime_spec.lua
@@ -0,0 +1,24 @@
+local luatz = require "luatz.init"
+
+describe("strftime", function()
+	local strftime = luatz.strftime.strftime
+	local time = luatz.time()
+	for i, spec in ipairs {
+		"a", "A", "b", "B", "c", "C", "d", "D", "e", "F",
+		"g", "G", "H", "I", "j", "m", "M", "n", "p", "r",
+		"R", --[["s",]] "S", "t", "T", "u", "U", "V", "w", "W",
+		"y", "Y", "z", "Z" , "%"
+	} do
+		local tt = luatz.gmtime(time)
+		it("Specifier "..spec.." is equivalent to os.date", function()
+			local f = "%"..spec
+			local osdf = "!%"..spec
+			for i=1, 365*12 do
+				local t = time + 60*60*24*i
+				tt.day = tt.day + 1
+				tt:normalise ( )
+				assert.are.same(os.date(osdf,t), strftime(f,tt))
+			end
+		end)
+	end
+end)