Initial Commit

diff --git a/gettime.lua b/gettime.lua
new file mode 100644 (file)
index 0000000..a86829e
--- /dev/null
+++ b/gettime.lua
@@ -0,0 +1,10 @@
+local _M = { }
+
+local has_socket , socket = pcall ( require , "socket" )
+if has_socket then
+       _M.gettime = socket.gettime
+else
+       _M.gettime = os.time
+end
+
+return _M

diff --git a/init.lua b/init.lua
new file mode 100644 (file)
index 0000000..5c4217f
--- /dev/null
+++ b/init.lua
@@ -0,0 +1,10 @@
+local get_tz = require "luatz.tzcache".get_tz
+
+local function gettimein ( tz , now )
+       return get_tz ( tz ):localize ( now )
+end
+
+return {
+       get_tz = get_tz ;
+       gettimein = gettimein ;
+}

diff --git a/tzcache.lua b/tzcache.lua
new file mode 100644 (file)
index 0000000..72ae401
--- /dev/null
+++ b/tzcache.lua
@@ -0,0 +1,30 @@
+local read_tzfile = require "luatz.tzfile".read_tzfile
+
+local tz_cache = { }
+
+local function name_to_zoneinfo_path ( name )
+       if name then
+               return "/usr/share/zoneinfo/" .. name
+       else
+               return "/etc/localtime"
+       end
+end
+
+local function clear_tz_cache ( name )
+       tz_cache [ name_to_zoneinfo_path ( name ) ] = nil
+end
+
+local function get_tz ( name )
+       local path = name_to_zoneinfo_path ( name )
+       local tzinfo = tz_cache [ path ]
+       if tzinfo == nil then
+               tzinfo = read_tzfile ( path )
+               tz_cache [ path ] = tzinfo
+       end
+       return tzinfo
+end
+
+return {
+       get_tz = get_tz ;
+       clear_tz_cache = clear_tz_cache ;
+}

diff --git a/tzfile.lua b/tzfile.lua
new file mode 100644 (file)
index 0000000..86af594
--- /dev/null
+++ b/tzfile.lua
@@ -0,0 +1,211 @@
+local gettime = require "luatz.gettime".gettime
+local tz_info_mt = require "luatz.tzinfo".tz_info_mt
+
+local function read_int32be ( fd )
+       local data , err = fd:read ( 4 )
+       if data == nil then return nil , err end
+       local o1 , o2 , o3 , o4 = data:byte ( 1 , 4 )
+
+       local unsigned = o4 + o3*2^8 + o2*2^16 + o1*2^24
+       if unsigned >= 2^31 then
+               return unsigned - 2^32
+       else
+               return unsigned
+       end
+end
+
+local function read_int64be ( fd )
+       local data , err = fd:read ( 8 )
+       if data == nil then return nil , err end
+       local o1 , o2 , o3 , o4 , o5 , o6 , o7 , o8 = data:byte ( 1 , 8 )
+
+       local unsigned = o8 + o7*2^8 + o6*2^16 + o5*2^24 + o4*2^32 + o3*2^40 + o2*2^48 + o1*2^56
+       if unsigned >= 2^63 then
+               return unsigned - 2^64
+       else
+               return unsigned
+       end
+end
+
+local function read_flags ( fd , n )
+       local data , err = fd:read ( n )
+       if data == nil then return nil , err end
+
+       local res = { }
+       for i=1, n do
+               res[i] = data:byte(i,i) ~= 0
+       end
+       return res
+end
+
+local fifteen_nulls = ("\0"):rep(15)
+local function read_tz ( fd )
+       assert ( fd:read(4) == "TZif" )
+       local version = assert ( fd:read(1) )
+       if version == "\0" or version == "2" then
+               local MIN_TIME = -2^32+1
+
+               assert ( assert ( fd:read(15) ) == fifteen_nulls , "Expected 15 nulls" )
+
+               -- The number of UTC/local indicators stored in the file.
+               local tzh_ttisgmtcnt = assert ( read_int32be ( fd ) )
+
+               -- The number of standard/wall indicators stored in the file.
+               local tzh_ttisstdcnt = assert ( read_int32be ( fd ) )
+
+               -- The number of leap seconds for which data is stored in the file.
+               local tzh_leapcnt = assert ( read_int32be ( fd ) )
+
+               -- The number of "transition times" for which data is stored in the file.
+               local tzh_timecnt = assert ( read_int32be ( fd ) )
+
+               -- The number of "local time types" for which data is stored in the file (must not be zero).
+               local tzh_typecnt = assert ( read_int32be ( fd ) )
+
+               -- The number of characters of "timezone abbreviation strings" stored in the file.
+               local tzh_charcnt = assert ( read_int32be ( fd ) )
+
+               local transition_times = { }
+               for i=1, tzh_timecnt do
+                       transition_times [ i ] = assert ( read_int32be ( fd ) )
+               end
+               local transition_time_ind = { assert ( fd:read ( tzh_timecnt ) ):byte ( 1 , -1 ) }
+
+               local ttinfos = { }
+               for i=1, tzh_typecnt do
+                       ttinfos [ i ] = {
+                               gmtoff = assert ( read_int32be ( fd ) ) ;
+                               isdst  = assert ( fd:read ( 1 ) ) ~= "\0" ;
+                               abbrind = assert ( fd:read ( 1 ) ):byte ( ) ;
+                       }
+               end
+
+               local abbreviations = assert ( fd:read ( tzh_charcnt ) )
+
+               local leap_seconds = { }
+               for i=1, tzh_leapcnt do
+                       leap_seconds [ i ] = {
+                               offset = assert ( read_int32be ( fd ) ) ;
+                               n = assert ( read_int32be ( fd ) ) ;
+                       }
+               end
+
+               local isstd = assert ( read_flags ( fd , tzh_ttisstdcnt ) )
+
+               local isgmt = assert ( read_flags ( fd , tzh_ttisgmtcnt ) )
+
+               if version == "2" then
+                       --[[
+                       For version-2-format timezone files, the above header and data is followed by a second header and data,
+                       identical in format except that eight bytes are used for each transition time or leap-second time.
+                       ]]
+                       assert ( fd:read(5) == "TZif2" )
+                       assert ( assert ( fd:read(15) ) == fifteen_nulls , "Expected 15 nulls" )
+
+                       MIN_TIME = -2^64+1
+
+                       -- The number of UTC/local indicators stored in the file.
+                       tzh_ttisgmtcnt = assert ( read_int32be ( fd ) )
+
+                       -- The number of standard/wall indicators stored in the file.
+                       tzh_ttisstdcnt = assert ( read_int32be ( fd ) )
+
+                       -- The number of leap seconds for which data is stored in the file.
+                       tzh_leapcnt = assert ( read_int32be ( fd ) )
+
+                       -- The number of "transition times" for which data is stored in the file.
+                       tzh_timecnt = assert ( read_int32be ( fd ) )
+
+                       -- The number of "local time types" for which data is stored in the file (must not be zero).
+                       tzh_typecnt = assert ( read_int32be ( fd ) )
+
+                       -- The number of characters of "timezone abbreviation strings" stored in the file.
+                       tzh_charcnt = assert ( read_int32be ( fd ) )
+
+                       transition_times = { }
+                       for i=1, tzh_timecnt do
+                               transition_times [ i ] = assert ( read_int64be ( fd ) )
+                       end
+                       transition_time_ind = { assert ( fd:read ( tzh_timecnt ) ):byte ( 1 , -1 ) }
+
+                       ttinfos = { }
+                       for i=1, tzh_typecnt do
+                               ttinfos [ i ] = {
+                                       gmtoff = assert ( read_int32be ( fd ) ) ;
+                                       isdst  = assert ( fd:read ( 1 ) ) ~= "\0" ;
+                                       abbrind = assert ( fd:read ( 1 ) ):byte ( ) ;
+                               }
+                       end
+
+                       abbreviations = assert ( fd:read ( tzh_charcnt ) )
+
+                       leap_seconds = { }
+                       for i=1, tzh_leapcnt do
+                               leap_seconds [ i ] = {
+                                       offset = assert ( read_int64be ( fd ) ) ;
+                                       n = assert ( read_int32be ( fd ) ) ;
+                               }
+                       end
+
+                       isstd = assert ( read_flags ( fd , tzh_ttisstdcnt ) )
+
+                       isgmt = assert ( read_flags ( fd , tzh_ttisgmtcnt ) )
+
+                       --[[
+                       After the second header and data comes a newline-enclosed, POSIX-TZ-environment-variable-style string
+                       for use in handling instants after the last transition time stored in the file
+                       (with nothing between the newlines if there is no POSIX representation for such instants).
+                       ]]
+               end
+
+               for i=1, tzh_typecnt do
+                       local v = ttinfos [ i ]
+                       v.abbr = abbreviations:sub ( v.abbrind+1 , v.abbrind+3 )
+                       v.isstd = isstd [ i ] or false
+                       v.isgmt = isgmt [ i ] or false
+               end
+
+               --[[
+               Use the first standard-time ttinfo structure in the file
+               (or simply the first ttinfo structure in the absence of a standard-time structure)
+               if either tzh_timecnt is zero or the time argument is less than the first transition time recorded in the file.
+               ]]
+               local first = 1
+               do
+                       for i=1, tzh_ttisstdcnt do
+                               if isstd[i] then
+                                       first = i
+                                       break
+                               end
+                       end
+               end
+
+               local res = {
+                       [0] = {
+                               transition_time = MIN_TIME ;
+                               info = ttinfos [ first ] ;
+                       }
+               }
+               for i=1, tzh_timecnt do
+                       res [ i ] = {
+                               transition_time = transition_times [ i ] ;
+                               info = ttinfos [ transition_time_ind [ i ]+1 ] ;
+                       }
+               end
+               return setmetatable ( res , tz_info_mt )
+       else
+               error ( "Unsupported version" )
+       end
+end
+
+local function read_tzfile ( path )
+       local fd = assert ( io.open ( path ) )
+       local tzinfo = read_tz ( fd )
+       fd:close ( )
+       return tzinfo
+end
+
+return {
+       read_tz = read_tz ;
+       read_tzfile = read_tzfile ;
+}

diff --git a/tzinfo.lua b/tzinfo.lua
new file mode 100644 (file)
index 0000000..66589d9
--- /dev/null
+++ b/tzinfo.lua
@@ -0,0 +1,29 @@
+local tz_info_methods = { }
+local tz_info_mt = {
+       __index = tz_info_methods ;
+}
+
+-- Binary search
+local function _find_current ( tzinfo , target , i , j )
+       if i >= j then return j end
+
+       local half = math.ceil ( (j+i) / 2 )
+
+       if target > tzinfo [ half ].transition_time then
+               return _find_current ( tzinfo , target , half , j )
+       else
+               return _find_current ( tzinfo , target , i , half-1 )
+       end
+end
+function tz_info_methods:find_current ( current )
+       return self [ _find_current ( self , current , 0 , #self ) ].info
+end
+
+function tz_info_methods:localize ( utc_ts )
+       utc_ts = utc_ts or gettime ( )
+       return utc_ts + self:find_current ( utc_ts ).gmtoff
+end
+
+return {
+       tz_info_mt = tz_info_mt ;
+}