From 97f3375906b56c5dfaddfcdb5208002919006ad1 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Fri, 2 Jan 2015 16:48:04 -0500
Subject: [PATCH] luatz/tzfile: Use string.unpack when available (Lua 5.3+)

---
 luatz/tzfile.lua | 53 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/luatz/tzfile.lua b/luatz/tzfile.lua
index a3fa794..d4285c4 100644
--- a/luatz/tzfile.lua
+++ b/luatz/tzfile.lua
@@ -1,30 +1,45 @@
 local tz_info_mt = require "luatz.tzinfo".tz_info_mt
 local tt_info_mt = require "luatz.tzinfo".tt_info_mt
 
+local read_int32be, read_int64be
 
-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 )
+if string.unpack then -- Only available in Lua 5.3+
+	function read_int32be(fd)
+		local data, err = fd:read(4)
+		if data == nil then return nil, err end
+		return string.unpack(">i4", data)
+	end
 
-	local unsigned = o4 + o3*2^8 + o2*2^16 + o1*2^24
-	if unsigned >= 2^31 then
-		return unsigned - 2^32
-	else
-		return unsigned
+	function read_int64be(fd)
+		local data, err = fd:read(8)
+		if data == nil then return nil, err end
+		return string.unpack(">i8", data)
+	end
+else
+	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
-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 )
+	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
+		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
 end
 
-- 
2.39.2