scummvm/sound/timestamp.cpp

76 lines
2.1 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.
*
* $URL$
* $Id$
*
*/
#include "sound/timestamp.h"
namespace Audio {
Timestamp::Timestamp() :
_msecs(0), _frameRate(0), _frameOffset(0) {
}
Timestamp::Timestamp(uint32 m, int frameRate) :
_msecs(m), _frameRate(frameRate), _frameOffset(0) {
}
Timestamp Timestamp::addFrames(int frames) const {
Timestamp timestamp(*this);
timestamp._frameOffset += frames;
if (timestamp._frameOffset < 0) {
int secsub = 1 + (-timestamp._frameOffset / timestamp._frameRate);
timestamp._frameOffset += timestamp._frameRate * secsub;
timestamp._msecs -= secsub * 1000;
}
timestamp._msecs += (timestamp._frameOffset / timestamp._frameRate) * 1000;
timestamp._frameOffset %= timestamp._frameRate;
return timestamp;
}
int Timestamp::frameDiff(const Timestamp &b) const {
assert(_frameRate == b._frameRate);
int msecdelta = 0;
if (_msecs != b._msecs)
msecdelta = (long(_msecs) - long(b._msecs)) * _frameRate / 1000;
return msecdelta + _frameOffset - b._frameOffset;
}
int Timestamp::msecsDiff(const Timestamp &b) const {
return long(msecs()) - long(b.msecs());
}
uint32 Timestamp::msecs() const {
return _msecs + _frameOffset * 1000L / _frameRate;
}
} // End of namespace Audio