From 70e049261c2b49411fbc9cefc737bc18ee6c4365 Mon Sep 17 00:00:00 2001
From: beware <beware@bircd.org>
Date: Mon, 3 Nov 2014 00:38:20 +0000
Subject: [PATCH] automatically use GetSystemTimePreciseAsFileTime if available
 (windows 8)

git-svn-id: file:///svnroot/lcore/trunk@140 b1de8a11-f9be-4011-bde0-cc7ace90066a
---
 btime.pas | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/btime.pas b/btime.pas
index 14b734e..54deae5 100644
--- a/btime.pas
+++ b/btime.pas
@@ -553,12 +553,51 @@ begin
   result := mmqpctimefloat;
 end;
 
+
+
+var
+  GetSystemTimePreciseAsFileTime:procedure(var v:tfiletime); stdcall;
+  win8inited:boolean;
+
+procedure initwin8;
+var
+  dllhandle:thandle;
+
+begin
+  win8inited := true;
+  dllhandle := loadlibrary('kernel32.dll');
+  if (dllhandle <> 0) then begin
+    GetSystemTimePreciseAsFileTime := getprocaddress(dllhandle,'GetSystemTimePreciseAsFileTime');
+  end;
+end;
+
+
+function unixtimefloat_win8:float;
+var
+  ft:tfiletime;
+  i:int64 absolute ft;
+begin
+  GetSystemTimePreciseAsFileTime(ft);
+  {change from windows 1601-01-01 to unix 1970-01-01.
+  use integer math for this, to preserve precision}
+  dec(i, 116444736000000000);
+  result := (i / 10000000);
+end;
+
+
+
 function unixtimefloat:float;
 const
   margin = 0.0012;
 var
   f,g,h:float;
 begin
+  if not win8inited then initwin8;
+  if assigned(@GetSystemTimePreciseAsFileTime) then begin
+    result := unixtimefloat_win8;
+    exit;
+  end;
+
   result := monotimefloat+timefloatbias;
   f := result-unixtimefloat_systemtime;
   if ((f > ticks_freq2+margin) or (f < -margin)) or (timefloatbias = 0) then begin
-- 
2.30.2