src/RateLimiter.cpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #include "RateLimiter.hpp"
  25
  26 #include <assert.h>
  27
  28 RateLimiter::RateLimiter(unsigned _period_ms, unsigned _delay_ms)
  29   :period_ms(_period_ms - _delay_ms), delay_ms(_delay_ms)
  30 {
  31   assert(_period_ms >= _delay_ms);
  32 }
  33
  34 void
  35 RateLimiter::Trigger()
  36 {
  37   if (IsActive())
  38     return;
  39
  40   unsigned schedule_ms = delay_ms;
  41   int elapsed = clock.Elapsed();
  42   if (elapsed >= 0 && (unsigned)elapsed < period_ms)
  43     schedule_ms += period_ms - elapsed;
  44
  45   Schedule(schedule_ms);
  46 }
  47
  48 void
  49 RateLimiter::OnTimer()
  50 {
  51   Timer::Cancel();
  52
  53   clock.Update();
  54   Run();
  55 }