src/Utils/HighResClock.h

   1 // TortoiseSVN - a Windows shell extension for easy version control
   2
   3 // Copyright (C) 2007-2007 - TortoiseSVN
   4
   5 // This program is free software; you can redistribute it and/or
   6 // modify it under the terms of the GNU General Public License
   7 // as published by the Free Software Foundation; either version 2
   8 // of the License, or (at your option) any later version.
   9
  10 // This program is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14
  15 // You should have received a copy of the GNU General Public License
  16 // along with this program; if not, write to the Free Software Foundation,
  17 // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 //
  19 #pragma once
  20
  21 ///////////////////////////////////////////////////////////////
  22 //
  23 // CHighResClock
  24 //
  25 //              high resolution clock for performance measurement.
  26 //              Depending on the hardware it will provide µsec
  27 //              resolution and accuracy.
  28 //
  29 //              May not be available on all machines.
  30 //
  31 ///////////////////////////////////////////////////////////////
  32
  33 class CHighResClock
  34 {
  35 private:
  36
  37         LARGE_INTEGER start;
  38         LARGE_INTEGER taken;
  39
  40 public:
  41
  42         // construction (starts measurement) / destruction
  43
  44         CHighResClock()
  45         {
  46                 taken.QuadPart = 0;
  47                 Start();
  48         }
  49
  50         ~CHighResClock()
  51         {
  52         }
  53
  54         // (re-start)
  55
  56         void Start()
  57         {
  58                 QueryPerformanceCounter(&start);
  59         }
  60
  61         // set "taken" to time since last Start()
  62
  63         void Stop()
  64         {
  65                 QueryPerformanceCounter(&taken);
  66                 taken.QuadPart -= start.QuadPart;
  67         }
  68
  69         // time in microseconds between last Start() and last Stop()
  70
  71         DWORD GetMusecsTaken() const
  72         {
  73                 LARGE_INTEGER frequency;
  74                 QueryPerformanceFrequency(&frequency);
  75                 return (DWORD)((taken.QuadPart * 1000000) / frequency.QuadPart);
  76         }
  77 };