From 14e470582b4a0ca5567239c1910f7513b2cfbaa1 Mon Sep 17 00:00:00 2001
From: beware <beware@bircd.org>
Date: Tue, 7 Aug 2012 02:29:51 +0000
Subject: [PATCH] rename monotonic time to monotimefloat, added monotonic
 timefloat for linux and OS X, 64 bits unix ts, improve windows rate detection

git-svn-id: file:///svnroot/lcore/trunk@118 b1de8a11-f9be-4011-bde0-cc7ace90066a
---
 btime.pas | 201 ++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 135 insertions(+), 66 deletions(-)

diff --git a/btime.pas b/btime.pas
index 7adcdd8..e0b0c4b 100644
--- a/btime.pas
+++ b/btime.pas
@@ -19,6 +19,7 @@ uses
 
 type
   float=extended;
+  tunixtimeint={$ifdef ver100}longint;{$else}int64;{$endif}
 
 const
   colorburst=39375000/11;  {3579545.4545....}
@@ -26,33 +27,38 @@ const
 var
   timezone:integer;
   timezonestr:string;
-  irctime,unixtime:integer;
+  irctime,unixtime:tunixtimeint;
   tickcount:integer;
-  settimebias:integer;
+  settimebias:tunixtimeint;
   performancecountfreq:extended;
 
 function irctimefloat:float;
-function irctimeint:integer;
+function irctimeint:tunixtimeint;
 
+//unix timestamp (UTC) float seconds
 function unixtimefloat:float;
-function unixtimeint:integer;
+function unixtimeint:tunixtimeint;
 
+//monotonic float seconds
+function monotimefloat:float;
+
+//monotonic (alias, old function name)
 function wintimefloat:float;
 
-procedure settime(newtime:integer);
+procedure settime(newtime:tunixtimeint);
 procedure gettimezone;
 procedure timehandler;
 procedure init;
 
-function timestring(i:integer):string;
-function timestrshort(i:integer):string;
+function timestring(i:tunixtimeint):string;
+function timestrshort(i:tunixtimeint):string;
 
 {$ifdef win32}
 function unixtimefloat_systemtime:float;
 {$endif}
 
 function oletounixfloat(t:float):float;
-function oletounix(t:tdatetime):integer;
+function oletounix(t:tdatetime):tunixtimeint;
 function unixtoole(i:float):tdatetime;
 
 {$ifdef win32}
@@ -108,6 +114,9 @@ uses
     {$else}
       baseunix,unix,unixutil,sockets, {unixutil and sockets needed by unixstuff.inc on some compiler versions}
     {$endif}
+    {$ifdef linux}
+      dl,
+    {$endif}
   {$else}
     windows,unitsettc,mmsystem,
   {$endif}
@@ -125,7 +134,7 @@ begin
   result := t;
 end;
 
-function oletounix(t:tdatetime):integer;
+function oletounix(t:tdatetime):tunixtimeint;
 begin
   result := trunc(oletounixfloat(t));
 end;
@@ -163,12 +172,86 @@ begin
   result := tv.tv_sec+(tv.tv_usec/1000000);
 end;
 
-function wintimefloat:extended;
-begin
-  result := unixtimefloat;
-end;
+{$ifdef linux}
+  {$define monotimefloat_implemented}
+  const
+    CLOCK_MONOTONIC = 1;
+  type 
+    ptimeval = ^ttimeval;
+    tclock_gettime = function(clk_id: integer; tp: ptimeval): integer; cdecl;
+
+  var
+    librt_handle:pointer;
+    librt_inited:boolean;
+    clock_gettime: tclock_gettime;
+
+  function monotimefloat:float;
+  var
+    ts: ttimeval;
+  begin
+    if not librt_inited then begin
+      librt_inited := true;
+      clock_gettime := nil;
+      librt_handle := dlopen('librt.so', RTLD_LAZY);
+      if assigned(librt_handle) then begin
+        clock_gettime := dlsym(librt_handle, 'clock_gettime');
+      end;
+    end;
+    if assigned(clock_gettime) then begin
+      if clock_gettime(CLOCK_MONOTONIC, @ts) = 0 then begin
+        //note this really returns nanoseconds
+        result := ts.tv_sec + ts.tv_usec / 1000000000.0;
+        exit;
+      end;
+    end;
+    //fallback
+    result := unixtimefloat;
+  end;
+
+
+{$endif} {linux}
+
+{$ifdef darwin} {mac OS X}
+{$define monotimefloat_implemented}
+
+  type
+    tmach_timebase_info = packed record
+      numer: longint;
+      denom: longint;
+    end;
+    pmach_timebase_info = ^tmach_timebase_info;
+     
+    function mach_absolute_time: int64; cdecl; external;
+    function mach_timebase_info(info: pmach_timebase_info): integer; cdecl; external;
+
+  var
+    timebase_info: tmach_timebase_info;
+
+  function monotimefloat:float;
+  var
+    i:int64;
+  begin
+    if timebase_info.denom = 0 then begin
+      mach_timebase_info(@timebase_info);
+    end;
+    i := mach_absolute_time;
+    result := (i * timebase_info.numer div timebase_info.denom) / 1000000000.0;
+  end;
+
+{$endif} {darwin, mac OS X}
+
 
-function unixtimeint:integer;
+{$ifndef monotimefloat_implemented} {fallback}
+  
+  function monotimefloat:extended;
+  begin
+    result := unixtimefloat;
+  end;
+
+{$endif} {monotimefloat fallback}
+
+
+function unixtimeint:tunixtimeint;
 var
   tv:ttimeval;
 begin
@@ -176,6 +259,8 @@ begin
   result := tv.tv_sec;
 end;
 
+{------------------------------ end of *nix/freepascal section}
+
 {$else} {delphi 3}
 {------------------------------ windows/delphi code to read time}
 
@@ -210,6 +295,7 @@ const
   wrapduration=highdwordconst * 0.001;
 var
   i:integer;
+  temp:float;
 begin
   i := gettickcount; {timegettime}
   if i < mmtime_last then begin
@@ -218,7 +304,17 @@ begin
   mmtime_last := i;
   result := mmtime_wrapadd + i * 0.001;
 
-  if (ticks_freq <> 0) and ticks_freq_known then result := int((result / ticks_freq)+0.5) * ticks_freq; //turn the float into an exact multiple of 1/64th sec to improve accuracy of things using this
+  if (ticks_freq <> 0) and ticks_freq_known then begin
+    {the value we get is rounded to 1 ms, but the ticks are not a multiple of 1 ms
+    this makes the value noisy. use the known ticks frequency to restore the original value}
+    temp := int((result / ticks_freq)+0.5) * ticks_freq;
+
+    {if the known ticks freq is wrong (can happen), disable the un-rounding behavior
+    this will be a bit less accurate but it prevents problems}
+    if abs(temp - result) > 0.002 then begin
+      ticks_freq := 0;
+    end else result := temp;
+  end;
 end;
 
 procedure measure_ticks_freq;
@@ -227,6 +323,8 @@ var
   o:tosversioninfo;
   isnt:boolean;
 {  is9x:boolean;}
+  adjust1,adjust2:cardinal;
+  adjustbool:longbool;
 begin
   if (performancecountfreq = 0) then qpctimefloat;
   ticks_freq_known := false;
@@ -243,49 +341,15 @@ begin
 
   ticks_freq2 := f;
   mmtime_synchedqpc := false;
-  {
-  NT 5 64 Hz (RTC)
-  identify mode as: nt64
-  QPC rate: either 3579545 or TSC freq
-  QPC synched to gettickcount: no
-  duration between 2 ticks is constant: yes
-  gettickcount tick duration: 64 Hz
-
-  NT 6 64 Hz (HPET?)
-  identify mode as: nt64
-  QPC rate: TSC freq / 1000
-  QPC synched to gettickcount: no
-  duration between 2 ticks is constant: yes
-  gettickcount tick duration: ~15.6001007 ms, ~64.102 Hz
-
-  }
-  if (f >= 0.014) and (f <= 0.018) and isnt then begin
-    if (performancecountfreq = 3579545) or (performancecountfreq > 50000000) then begin
-      {typical XP}
-      ticks_freq := 1/64;
-    end else begin
-      {typical windows 7}
-      ticks_freq := 0.0156001007;
-    end;
-    ticks_freq_known := true;
-    mmtime_synchedqpc := false;
-  end;
 
-  {
-  NT 100 Hz
-  identify mode as: nt100
-  QPC rate: 1193182
-  QPC synched to gettickcount: yes
-  duration between 2 ticks is constant: no?
-  gettickcount tick duration: ~99.85 Hz
-  }
-  if (performancecountfreq = 1193182) and (f >= 0.008) and (f <= 0.012) and isnt then begin
-    ticks_freq_known := true;
-    ticks_freq2 := 11949 / (colorburst / 3);
-   //  ticks_freq2 := 11949 / 1193182;
-    ticks_freq := 0;
-    {the ticks freq should be very close to the real one but if it's not exact, it will cause drift and correction jumps}
-    mmtime_synchedqpc := true;
+  if (isnt and (o.dwMajorVersion >= 5)) then begin
+    {windows 2000 and later: query tick rate from OS in 100 ns units
+    typical rates: XP: 156250 or 100144, windows 7: 156001}
+    if GetSystemTimeAdjustment(adjust1,adjust2,adjustbool) then begin
+      ticks_freq := adjust1 / 10000000.0;
+      ticks_freq_known := true;
+      mmtime_synchedqpc := false;
+    end;
   end;
 
   {9x}
@@ -482,7 +546,7 @@ begin
   result := oletounixfloat(int(date_utc+0.5))+time_utc*86400;
 end;
 
-function wintimefloat:extended;
+function monotimefloat:extended;
 begin
   result := mmqpctimefloat;
 end;
@@ -493,13 +557,13 @@ const
 var
   f,g,h:float;
 begin
-  result := wintimefloat+timefloatbias;
+  result := monotimefloat+timefloatbias;
   f := result-unixtimefloat_systemtime;
   if ((f > ticks_freq2+margin) or (f < -margin)) or (timefloatbias = 0) then begin
 //    writeln('unixtimefloat init');
     f := unixtimefloat_systemtime;
     settc;
-    repeat g := unixtimefloat_systemtime; h := wintimefloat until g > f;
+    repeat g := unixtimefloat_systemtime; h := monotimefloat until g > f;
     unsettc;
     timefloatbias := g-h;
     result := unixtimefloat;
@@ -510,7 +574,7 @@ begin
   lastunixtimefloat := result;
 end;
 
-function unixtimeint:integer;
+function unixtimeint:tunixtimeint;
 begin
   result := trunc(unixtimefloat);
 end;
@@ -518,20 +582,25 @@ end;
 {$endif}
 {-----------------------------------------------end of platform specific}
 
+function wintimefloat:float;
+begin
+  result := monotimefloat;
+end;
+
 function irctimefloat:float;
 begin
   result := unixtimefloat+settimebias;
 end;
 
-function irctimeint:integer;
+function irctimeint:tunixtimeint;
 begin
   result := unixtimeint+settimebias;
 end;
 
 
-procedure settime(newtime:integer);
+procedure settime(newtime:tunixtimeint);
 var
-  a:integer;
+  a:tunixtimeint;
 begin
   a := irctimeint-settimebias;
   if newtime = 0 then settimebias := 0 else settimebias := newtime-a;
@@ -587,7 +656,7 @@ begin
   timezonestr := timezonestr + char(l div 600 mod 10+48)+char(l div 60 mod 10+48)+':'+char(l div 10 mod 6+48)+char(l mod 10+48);
 end;
 
-function timestrshort(i:integer):string;
+function timestrshort(i:tunixtimeint):string;
 const
   weekday:array[0..6] of string[4]=('Thu','Fri','Sat','Sun','Mon','Tue','Wed');
   month:array[0..11] of string[4]=('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
@@ -603,7 +672,7 @@ begin
   inttostr(y);
 end;
 
-function timestring(i:integer):string;
+function timestring(i:tunixtimeint):string;
 const
   weekday:array[0..6] of string[10]=('Thursday','Friday','Saturday','Sunday','Monday','Tuesday','Wednesday');
   month:array[0..11] of string[10]=('January','February','March','April','May','June','July','August','September','October','November','December');
-- 
2.30.2