scummvm/sound/timestamp.h
2009-05-28 10:29:25 +00:00

76 lines
2.2 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#ifndef SOUND_TIMESTAMP_H
#define SOUND_TIMESTAMP_H
#include "common/scummsys.h"
namespace Audio {
/**
* Timestamps allow measuring times with a sub-millisecond granularity,
* and without rounding losses. This is achieved by measuring frames
* instead of milliseconds: Specify an initial time in milliseconds
* plus framerate (in frames per second).
*/
class Timestamp {
protected:
uint32 _msecs;
int _frameRate;
int _frameOffset;
/* Total time: msecs + frame_offset/frame_rate */
public:
Timestamp();
/**
* Set up a timestamp with a given time and framerate.
* @param msecs staring time in milliseconds
* @param frameRate number of frames per second
*/
Timestamp(uint32 msecs, int frameRate);
/** Adds a number of frames to a timestamp. */
Timestamp addFrames(int frames) const;
/** Adds a number of milliseconds to a timestamp. */
Timestamp addMsecs(int ms) const;
/** Computes the difference (# of frames) between this timestamp and b. */
int frameDiff(const Timestamp &b) const;
/** Computes the difference (# of milliseconds) between this timestamp and b. */
int msecsDiff(const Timestamp &b) const;
/** Determines the time in milliseconds described by this timestamp. */
uint32 msecs() const;
};
} // End of namespace Audio
#endif