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--- Date and Date Format classes.
-- See @{05-dates.md|the Guide}.
--
-- Dependencies: `pl.class`, `pl.stringx`, `pl.utils`
-- @classmod pl.Date
-- @pragma nostrip
local class = require 'pl.class'
local os_time, os_date = os.time, os.date
local stringx = require 'pl.stringx'
local utils = require 'pl.utils'
local assert_arg,assert_string = utils.assert_arg,utils.assert_string
local Date = class()
Date.Format = class()
--- Date constructor.
-- @param t this can be either
--
-- * `nil` or empty - use current date and time
-- * number - seconds since epoch (as returned by `os.time`). Resulting time is UTC
-- * `Date` - make a copy of this date
-- * table - table containing year, month, etc as for `os.time`. You may leave out year, month or day,
-- in which case current values will be used.
-- * year (will be followed by month, day etc)
--
-- @param ... true if Universal Coordinated Time, or two to five numbers: month,day,hour,min,sec
-- @function Date
function Date:_init(t,...)
local time
local nargs = select('#',...)
if nargs > 2 then
local extra = {...}
local year = t
t = {
year = year,
month = extra[1],
day = extra[2],
hour = extra[3],
min = extra[4],
sec = extra[5]
}
end
if nargs == 1 then
self.utc = select(1,...) == true
end
if t == nil or t == 'utc' then
time = os_time()
self.utc = t == 'utc'
elseif type(t) == 'number' then
time = t
if self.utc == nil then self.utc = true end
elseif type(t) == 'table' then
if getmetatable(t) == Date then -- copy ctor
time = t.time
self.utc = t.utc
else
if not (t.year and t.month) then
local lt = os_date('*t')
if not t.year and not t.month and not t.day then
t.year = lt.year
t.month = lt.month
t.day = lt.day
else
t.year = t.year or lt.year
t.month = t.month or (t.day and lt.month or 1)
t.day = t.day or 1
end
end
t.day = t.day or 1
time = os_time(t)
end
else
error("bad type for Date constructor: "..type(t),2)
end
self:set(time)
end
--- set the current time of this Date object.
-- @int t seconds since epoch
function Date:set(t)
self.time = t
if self.utc then
self.tab = os_date('!*t',t)
else
self.tab = os_date('*t',t)
end
end
--- get the time zone offset from UTC.
-- @int ts seconds ahead of UTC
function Date.tzone (ts)
if ts == nil then
ts = os_time()
elseif type(ts) == "table" then
if getmetatable(ts) == Date then
ts = ts.time
else
ts = Date(ts).time
end
end
local utc = os_date('!*t',ts)
local lcl = os_date('*t',ts)
lcl.isdst = false
return os.difftime(os_time(lcl), os_time(utc))
end
--- convert this date to UTC.
function Date:toUTC ()
local ndate = Date(self)
if not self.utc then
ndate.utc = true
ndate:set(ndate.time)
end
return ndate
end
--- convert this UTC date to local.
function Date:toLocal ()
local ndate = Date(self)
if self.utc then
ndate.utc = false
ndate:set(ndate.time)
--~ ndate:add { sec = Date.tzone(self) }
end
return ndate
end
--- set the year.
-- @int y Four-digit year
-- @class function
-- @name Date:year
--- set the month.
-- @int m month
-- @class function
-- @name Date:month
--- set the day.
-- @int d day
-- @class function
-- @name Date:day
--- set the hour.
-- @int h hour
-- @class function
-- @name Date:hour
--- set the minutes.
-- @int min minutes
-- @class function
-- @name Date:min
--- set the seconds.
-- @int sec seconds
-- @class function
-- @name Date:sec
--- set the day of year.
-- @class function
-- @int yday day of year
-- @name Date:yday
--- get the year.
-- @int y Four-digit year
-- @class function
-- @name Date:year
--- get the month.
-- @class function
-- @name Date:month
--- get the day.
-- @class function
-- @name Date:day
--- get the hour.
-- @class function
-- @name Date:hour
--- get the minutes.
-- @class function
-- @name Date:min
--- get the seconds.
-- @class function
-- @name Date:sec
--- get the day of year.
-- @class function
-- @name Date:yday
for _,c in ipairs{'year','month','day','hour','min','sec','yday'} do
Date[c] = function(self,val)
if val then
assert_arg(1,val,"number")
self.tab[c] = val
self:set(os_time(self.tab))
return self
else
return self.tab[c]
end
end
end
--- name of day of week.
-- @bool full abbreviated if true, full otherwise.
-- @ret string name
function Date:weekday_name(full)
return os_date(full and '%A' or '%a',self.time)
end
--- name of month.
-- @int full abbreviated if true, full otherwise.
-- @ret string name
function Date:month_name(full)
return os_date(full and '%B' or '%b',self.time)
end
--- is this day on a weekend?.
function Date:is_weekend()
return self.tab.wday == 1 or self.tab.wday == 7
end
--- add to a date object.
-- @param t a table containing one of the following keys and a value:
-- one of `year`,`month`,`day`,`hour`,`min`,`sec`
-- @return this date
function Date:add(t)
local old_dst = self.tab.isdst
local key,val = next(t)
self.tab[key] = self.tab[key] + val
self:set(os_time(self.tab))
if old_dst ~= self.tab.isdst then
self.tab.hour = self.tab.hour - (old_dst and 1 or -1)
self:set(os_time(self.tab))
end
return self
end
--- last day of the month.
-- @return int day
function Date:last_day()
local d = 28
local m = self.tab.month
while self.tab.month == m do
d = d + 1
self:add{day=1}
end
self:add{day=-1}
return self
end
--- difference between two Date objects.
-- @tparam Date other Date object
-- @treturn Date.Interval object
function Date:diff(other)
local dt = self.time - other.time
if dt < 0 then error("date difference is negative!",2) end
return Date.Interval(dt)
end
--- long numerical ISO data format version of this date.
function Date:__tostring()
local fmt = '%Y-%m-%dT%H:%M:%S'
if self.utc then
fmt = "!"..fmt
end
local t = os_date(fmt,self.time)
if self.utc then
return t .. 'Z'
else
local offs = self:tzone()
if offs == 0 then
return t .. 'Z'
end
local sign = offs > 0 and '+' or '-'
local h = math.ceil(offs/3600)
local m = (offs % 3600)/60
if m == 0 then
return t .. ('%s%02d'):format(sign,h)
else
return t .. ('%s%02d:%02d'):format(sign,h,m)
end
end
end
--- equality between Date objects.
function Date:__eq(other)
return self.time == other.time
end
--- ordering between Date objects.
function Date:__lt(other)
return self.time < other.time
end
--- difference between Date objects.
-- @function Date:__sub
Date.__sub = Date.diff
--- add a date and an interval.
-- @param other either a `Date.Interval` object or a table such as
-- passed to `Date:add`
function Date:__add(other)
local nd = Date(self)
if Date.Interval:class_of(other) then
other = {sec=other.time}
end
nd:add(other)
return nd
end
Date.Interval = class(Date)
---- Date.Interval constructor
-- @int t an interval in seconds
-- @function Date.Interval
function Date.Interval:_init(t)
self:set(t)
end
function Date.Interval:set(t)
self.time = t
self.tab = os_date('!*t',self.time)
end
local function ess(n)
if n > 1 then return 's '
else return ' '
end
end
--- If it's an interval then the format is '2 hours 29 sec' etc.
function Date.Interval:__tostring()
local t, res = self.tab, ''
local y,m,d = t.year - 1970, t.month - 1, t.day - 1
if y > 0 then res = res .. y .. ' year'..ess(y) end
if m > 0 then res = res .. m .. ' month'..ess(m) end
if d > 0 then res = res .. d .. ' day'..ess(d) end
if y == 0 and m == 0 then
local h = t.hour
if h > 0 then res = res .. h .. ' hour'..ess(h) end
if t.min > 0 then res = res .. t.min .. ' min ' end
if t.sec > 0 then res = res .. t.sec .. ' sec ' end
end
if res == '' then res = 'zero' end
return res
end
------------ Date.Format class: parsing and renderinig dates ------------
-- short field names, explicit os.date names, and a mask for allowed field repeats
local formats = {
d = {'day',{true,true}},
y = {'year',{false,true,false,true}},
m = {'month',{true,true}},
H = {'hour',{true,true}},
M = {'min',{true,true}},
S = {'sec',{true,true}},
}
--- Date.Format constructor.
-- @string fmt. A string where the following fields are significant:
--
-- * d day (either d or dd)
-- * y year (either yy or yyy)
-- * m month (either m or mm)
-- * H hour (either H or HH)
-- * M minute (either M or MM)
-- * S second (either S or SS)
--
-- Alternatively, if fmt is nil then this returns a flexible date parser
-- that tries various date/time schemes in turn:
--
-- * [ISO 8601](http://en.wikipedia.org/wiki/ISO_8601), like `2010-05-10 12:35:23Z` or `2008-10-03T14:30+02`
-- * times like 15:30 or 8.05pm (assumed to be today's date)
-- * dates like 28/10/02 (European order!) or 5 Feb 2012
-- * month name like march or Mar (case-insensitive, first 3 letters); here the
-- day will be 1 and the year this current year
--
-- A date in format 3 can be optionally followed by a time in format 2.
-- Please see test-date.lua in the tests folder for more examples.
-- @usage df = Date.Format("yyyy-mm-dd HH:MM:SS")
-- @class function
-- @name Date.Format
function Date.Format:_init(fmt)
if not fmt then
self.fmt = '%Y-%m-%d %H:%M:%S'
self.outf = self.fmt
self.plain = true
return
end
local append = table.insert
local D,PLUS,OPENP,CLOSEP = '\001','\002','\003','\004'
local vars,used = {},{}
local patt,outf = {},{}
local i = 1
while i < #fmt do
local ch = fmt:sub(i,i)
local df = formats[ch]
if df then
if used[ch] then error("field appeared twice: "..ch,4) end
used[ch] = true
-- this field may be repeated
local _,inext = fmt:find(ch..'+',i+1)
local cnt = not _ and 1 or inext-i+1
if not df[2][cnt] then error("wrong number of fields: "..ch,4) end
-- single chars mean 'accept more than one digit'
local p = cnt==1 and (D..PLUS) or (D):rep(cnt)
append(patt,OPENP..p..CLOSEP)
append(vars,ch)
if ch == 'y' then
append(outf,cnt==2 and '%y' or '%Y')
else
append(outf,'%'..ch)
end
i = i + cnt
else
append(patt,ch)
append(outf,ch)
i = i + 1
end
end
-- escape any magic characters
fmt = utils.escape(table.concat(patt))
-- fmt = table.concat(patt):gsub('[%-%.%+%[%]%(%)%$%^%%%?%*]','%%%1')
-- replace markers with their magic equivalents
fmt = fmt:gsub(D,'%%d'):gsub(PLUS,'+'):gsub(OPENP,'('):gsub(CLOSEP,')')
self.fmt = fmt
self.outf = table.concat(outf)
self.vars = vars
end
local parse_date
--- parse a string into a Date object.
-- @string str a date string
-- @return date object
function Date.Format:parse(str)
assert_string(1,str)
if self.plain then
return parse_date(str,self.us)
end
local res = {str:match(self.fmt)}
if #res==0 then return nil, 'cannot parse '..str end
local tab = {}
for i,v in ipairs(self.vars) do
local name = formats[v][1] -- e.g. 'y' becomes 'year'
tab[name] = tonumber(res[i])
end
-- os.date() requires these fields; if not present, we assume
-- that the time set is for the current day.
if not (tab.year and tab.month and tab.day) then
local today = Date()
tab.year = tab.year or today:year()
tab.month = tab.month or today:month()
tab.day = tab.day or today:day()
end
local Y = tab.year
if Y < 100 then -- classic Y2K pivot
tab.year = Y + (Y < 35 and 2000 or 1999)
elseif not Y then
tab.year = 1970
end
return Date(tab)
end
--- convert a Date object into a string.
-- @param d a date object, or a time value as returned by @{os.time}
-- @return string
function Date.Format:tostring(d)
local tm
local fmt = self.outf
if type(d) == 'number' then
tm = d
else
tm = d.time
if d.utc then
fmt = '!'..fmt
end
end
return os_date(fmt,tm)
end
--- force US order in dates like 9/11/2001
function Date.Format:US_order(yesno)
self.us = yesno
end
--local months = {jan=1,feb=2,mar=3,apr=4,may=5,jun=6,jul=7,aug=8,sep=9,oct=10,nov=11,dec=12}
local months
local parse_date_unsafe
local function create_months()
local ld, day1 = parse_date_unsafe '2000-12-31', {day=1}
months = {}
for i = 1,12 do
ld = ld:last_day()
ld:add(day1)
local mon = ld:month_name():lower()
months [mon] = i
end
end
--[[
Allowed patterns:
- [day] [monthname] [year] [time]
- [day]/[month][/year] [time]
]]
local function looks_like_a_month(w)
return w:match '^%a+,*$' ~= nil
end
local is_number = stringx.isdigit
local function tonum(s,l1,l2,kind)
kind = kind or ''
local n = tonumber(s)
if not n then error(("%snot a number: '%s'"):format(kind,s)) end
if n < l1 or n > l2 then
error(("%s out of range: %s is not between %d and %d"):format(kind,s,l1,l2))
end
return n
end
local function parse_iso_end(p,ns,sec)
-- may be fractional part of seconds
local _,nfrac,secfrac = p:find('^%.%d+',ns+1)
if secfrac then
sec = sec .. secfrac
p = p:sub(nfrac+1)
else
p = p:sub(ns+1)
end
-- ISO 8601 dates may end in Z (for UTC) or [+-][isotime]
-- (we're working with the date as lower case, hence 'z')
if p:match 'z$' then -- we're UTC!
return sec, {h=0,m=0}
end
p = p:gsub(':','') -- turn 00:30 to 0030
local _,_,sign,offs = p:find('^([%+%-])(%d+)')
if not sign then return sec, nil end -- not UTC
if #offs == 2 then offs = offs .. '00' end -- 01 to 0100
local tz = { h = tonumber(offs:sub(1,2)), m = tonumber(offs:sub(3,4)) }
if sign == '-' then tz.h = -tz.h; tz.m = -tz.m end
return sec, tz
end
function parse_date_unsafe (s,US)
s = s:gsub('T',' ') -- ISO 8601
local parts = stringx.split(s:lower())
local i,p = 1,parts[1]
local function nextp() i = i + 1; p = parts[i] end
local year,min,hour,sec,apm
local tz
local _,nxt,day, month = p:find '^(%d+)/(%d+)'
if day then
-- swop for US case
if US then
day, month = month, day
end
_,_,year = p:find('^/(%d+)',nxt+1)
nextp()
else -- ISO
year,month,day = p:match('^(%d+)%-(%d+)%-(%d+)')
if year then
nextp()
end
end
if p and not year and is_number(p) then -- has to be date
if #p < 4 then
day = p
nextp()
else -- unless it looks like a 24-hour time
year = true
end
end
if p and looks_like_a_month(p) then -- date followed by month
p = p:sub(1,3)
if not months then
create_months()
end
local mon = months[p]
if mon then
month = mon
else error("not a month: " .. p) end
nextp()
end
if p and not year and is_number(p) then
year = p
nextp()
end
if p then -- time is hh:mm[:ss], hhmm[ss] or H.M[am|pm]
_,nxt,hour,min = p:find '^(%d+):(%d+)'
local ns
if nxt then -- are there seconds?
_,ns,sec = p:find ('^:(%d+)',nxt+1)
--if ns then
sec,tz = parse_iso_end(p,ns or nxt,sec)
--end
else -- might be h.m
_,ns,hour,min = p:find '^(%d+)%.(%d+)'
if ns then
apm = p:match '[ap]m$'
else -- or hhmm[ss]
local hourmin
_,nxt,hourmin = p:find ('^(%d+)')
if nxt then
hour = hourmin:sub(1,2)
min = hourmin:sub(3,4)
sec = hourmin:sub(5,6)
if #sec == 0 then sec = nil end
sec,tz = parse_iso_end(p,nxt,sec)
end
end
end
end
local today
if year == true then year = nil end
if not (year and month and day) then
today = Date()
end
day = day and tonum(day,1,31,'day') or (month and 1 or today:day())
month = month and tonum(month,1,12,'month') or today:month()
year = year and tonumber(year) or today:year()
if year < 100 then -- two-digit year pivot around year < 2035
year = year + (year < 35 and 2000 or 1900)
end
hour = hour and tonum(hour,0,apm and 12 or 24,'hour') or 12
if apm == 'pm' then
hour = hour + 12
end
min = min and tonum(min,0,59) or 0
sec = sec and tonum(sec,0,60) or 0 --60 used to indicate leap second
local res = Date {year = year, month = month, day = day, hour = hour, min = min, sec = sec}
if tz then -- ISO 8601 UTC time
local corrected = false
if tz.h ~= 0 then res:add {hour = -tz.h}; corrected = true end
if tz.m ~= 0 then res:add {min = -tz.m}; corrected = true end
res.utc = true
-- we're in UTC, so let's go local...
if corrected then
res = res:toLocal()
end-- we're UTC!
end
return res
end
function parse_date (s)
local ok, d = pcall(parse_date_unsafe,s)
if not ok then -- error
d = d:gsub('.-:%d+: ','')
return nil, d
else
return d
end
end
return Date