Orca Robotics

00001 /*
00002  * Orca-Robotics Project: Components for robotics 
00003  *               http://orca-robotics.sf.net/
00004  * Copyright (c) 2004-2008 Alex Brooks, Alexei Makarenko, Tobias Kaupp
00005  *
00006  * This copy of Orca is licensed to you under the terms described in
00007  * the LICENSE file included in this distribution.
00008  *
00009  */
00010 
00011 #ifndef REPLAY_CLOCK_H
00012 #define REPLAY_CLOCK_H
00013 
00014 #include <IceUtil/Time.h>
00015 
00016 namespace logplayer
00017 {
00018 
00019 //
00020 // ReplayClock is used to make sure the log gets played with the correct timing
00021 // (possibly not real-time).
00022 //
00023 // The timing could also be controlled by just looking at time deltas between items,
00024 // but that would drift.  This provides some kind of absolute reference.
00025 //
00026 // We keep track of two things:
00027 //  1. real time since the start of continuous playback, and
00028 //  2. log time since the start of continuous playback.
00029 //
00030 class ReplayClock
00031 {
00032 public:
00033     // Throws an error string if replayRate is set to zero.
00034     ReplayClock( double replayRate=1.0 );
00035 
00036     void setReplayRate( double replayRate );
00037 
00038     // When we start continuous replay, use this call to tell the clock the
00039     // time (in log-space) of the first item.
00040     void setContinuousReplayStartTime( const IceUtil::Time &timeFirstLogItem );
00041 
00042     // Give it the time in log-land till the next item, it returns the
00043     // time we should wait in the real world.
00044     // Note: setContinuousReplayStartTime should have been called already.
00045     IceUtil::Time realTimeTillNextItem( const IceUtil::Time &logTimeTillNextItem );
00046 
00047 private:
00048 
00049     double replayRate_;
00050     IceUtil::Time logStartTime_;
00051     IceUtil::Time replayStartTime_;
00052 };
00053 
00054 } // namespace
00055 
00056 #endif
replayclock.h
