X-Git-Url: https://git.madduck.net/etc/awesome.git/blobdiff_plain/27e12c9a39aa33f8815964adedd036cd6703099f..d08da842dbdcc2b452fdb6a70cb82f6cc85dc118:/luatz/tzinfo.lua?ds=inline diff --git a/luatz/tzinfo.lua b/luatz/tzinfo.lua index 77d0656..e37483f 100644 --- a/luatz/tzinfo.lua +++ b/luatz/tzinfo.lua @@ -1,37 +1,51 @@ local gettime = require "luatz.gettime".gettime +local timetable_mt = require "luatz.timetable".timetable_mt + +local function to_timestamp(o) + if type(o) == "number" then + return o + elseif getmetatable(o) == timetable_mt then + return o:timestamp() + end +end local tz_info_methods = { } local tz_info_mt = { - __index = tz_info_methods ; + __name = "luatz.tz_info"; + __index = tz_info_methods; } local tt_info_mt = { + __name = "luatz.tt_info"; + __tostring = function(self) + return string.format("tt_info:%s=%d", self.abbr, self.gmtoff) + end; } -- Binary search -local function _find_current ( tzinfo , target , i , j ) +local function find_current(tzinfo, target, i, j) if i >= j then return j end - local half = math.ceil ( (j+i) / 2 ) + local half = math.ceil((j+i) / 2) - if target >= tzinfo [ half ].transition_time then - return _find_current ( tzinfo , target , half , j ) + if target >= tzinfo[half].transition_time then + return find_current(tzinfo, target, half, j) else - return _find_current ( tzinfo , target , i , half-1 ) + return find_current(tzinfo, target, i, half-1) end end -local function find_current_local ( tzinfo , ts_local ) +local function find_current_local(tzinfo, ts_local) -- Find two best possibilities by searching back and forward a day (assumes transition is never by more than 24 hours) - local tz_first = _find_current ( tzinfo , ts_local-86400 , 0 , #tzinfo ) - local tz_last = _find_current ( tzinfo , ts_local+86400 , 0 , #tzinfo ) + local tz_first = find_current(tzinfo, ts_local-86400, 0, #tzinfo) + local tz_last = find_current(tzinfo, ts_local+86400, 0, #tzinfo) local n_candidates = tz_last - tz_first + 1 if n_candidates == 1 then return tz_first elseif n_candidates == 2 then - local tz_first_ob = tzinfo [ tz_first ] - local tz_last_ob = tzinfo [ tz_last ] + local tz_first_ob = tzinfo[tz_first] + local tz_last_ob = tzinfo[tz_last] local first_gmtoffset = tz_first_ob.info.gmtoff local last_gmtoffset = tz_last_ob .info.gmtoff @@ -47,35 +61,37 @@ local function find_current_local ( tzinfo , ts_local ) end -- If we get this far, the local time is ambiguous - return tz_first , tz_last + return tz_first, tz_last else - error ( "Too many transitions in a 2 day period" ) + error("Too many transitions in a 2 day period") end end -function tz_info_methods:find_current ( current ) - return self [ _find_current ( self , current , 0 , #self ) ].info +function tz_info_methods:find_current(current) + current = assert(to_timestamp(current), "invalid timestamp to :find_current") + return self[find_current(self, current, 0, #self)].info end -function tz_info_methods:localise ( utc_ts ) - utc_ts = utc_ts or gettime ( ) - return utc_ts + self:find_current ( utc_ts ).gmtoff +function tz_info_methods:localise(utc_ts) + utc_ts = utc_ts or gettime() + return utc_ts + self:find_current(utc_ts).gmtoff end tz_info_methods.localize = tz_info_methods.localise -function tz_info_methods:utctime ( ts_local ) - local tz1 , tz2 = find_current_local ( self , ts_local ) - tz1 = self [ tz1 ].info +function tz_info_methods:utctime(ts_local) + ts_local = assert(to_timestamp(ts_local), "invalid timestamp to :utctime") + local tz1, tz2 = find_current_local(self, ts_local) + tz1 = self[tz1].info if tz2 == nil then return ts_local - tz1.gmtoff else -- Local time is ambiguous - tz2 = self [ tz2 ].info + tz2 = self[tz2].info - return ts_local - tz2.gmtoff , ts_local - tz2.gmtoff + return ts_local - tz2.gmtoff, ts_local - tz2.gmtoff end end return { - tz_info_mt = tz_info_mt ; - tt_info_mt = tt_info_mt ; + tz_info_mt = tz_info_mt; + tt_info_mt = tt_info_mt; }