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/* 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.
*
*/
#include "audio/timestamp.h"
#include "common/algorithm.h"
namespace Audio {
Timestamp::Timestamp(uint ms, uint fr) {
assert(fr > 0);
_secs = ms / 1000;
_framerateFactor = 1000 / Common::gcd<uint>(1000, fr);
_framerate = fr * _framerateFactor;
// Note that _framerate is always divisible by 1000.
_numFrames = (ms % 1000) * (_framerate / 1000);
}
Timestamp::Timestamp(uint s, uint frames, uint fr) {
assert(fr > 0);
_secs = s + (frames / fr);
_framerateFactor = 1000 / Common::gcd<uint>(1000, fr);
_framerate = fr * _framerateFactor;
_numFrames = (frames % fr) * _framerateFactor;
}
Timestamp Timestamp::convertToFramerate(uint newFramerate) const {
Timestamp ts(*this);
if (ts.framerate() != newFramerate) {
ts._framerateFactor = 1000 / Common::gcd<uint>(1000, newFramerate);
ts._framerate = newFramerate * ts._framerateFactor;
const uint g = Common::gcd(_framerate, ts._framerate);
const uint p = _framerate / g;
const uint q = ts._framerate / g;
// Convert the frame offset to the new framerate.
// We round to the nearest (as opposed to always
// rounding down), to minimize rounding errors during
// round trip conversions.
ts._numFrames = (ts._numFrames * q + p/2) / p;
ts.normalize();
}
return ts;
}
void Timestamp::normalize() {
// Convert negative _numFrames values to positive ones by adjusting _secs
if (_numFrames < 0) {
int secsub = 1 + (-_numFrames / _framerate);
_numFrames += _framerate * secsub;
_secs -= secsub;
}
// Wrap around if necessary
_secs += (_numFrames / _framerate);
_numFrames %= _framerate;
}
bool Timestamp::operator==(const Timestamp &ts) const {
return cmp(ts) == 0;
}
bool Timestamp::operator!=(const Timestamp &ts) const {
return cmp(ts) != 0;
}
bool Timestamp::operator<(const Timestamp &ts) const {
return cmp(ts) < 0;
}
bool Timestamp::operator<=(const Timestamp &ts) const {
return cmp(ts) <= 0;
}
bool Timestamp::operator>(const Timestamp &ts) const {
return cmp(ts) > 0;
}
bool Timestamp::operator>=(const Timestamp &ts) const {
return cmp(ts) >= 0;
}
int Timestamp::cmp(const Timestamp &ts) const {
int delta = _secs - ts._secs;
if (!delta) {
const uint g = Common::gcd(_framerate, ts._framerate);
const uint p = _framerate / g;
const uint q = ts._framerate / g;
delta = (_numFrames * q - ts._numFrames * p);
}
return delta;
}
Timestamp Timestamp::addFrames(int frames) const {
Timestamp ts(*this);
// The frames are given in the original framerate, so we have to
// adjust by _framerateFactor accordingly.
ts._numFrames += frames * _framerateFactor;
ts.normalize();
return ts;
}
Timestamp Timestamp::addMsecs(int ms) const {
Timestamp ts(*this);
ts._secs += ms / 1000;
// Add the remaining frames. Note that _framerate is always divisible by 1000.
ts._numFrames += (ms % 1000) * (ts._framerate / 1000);
ts.normalize();
return ts;
}
void Timestamp::addIntern(const Timestamp &ts) {
assert(_framerate == ts._framerate);
_secs += ts._secs;
_numFrames += ts._numFrames;
normalize();
}
Timestamp Timestamp::operator-() const {
Timestamp result(*this);
result._secs = -_secs;
result._numFrames = -_numFrames;
result.normalize();
return result;
}
Timestamp Timestamp::operator+(const Timestamp &ts) const {
Timestamp result(*this);
result.addIntern(ts);
return result;
}
Timestamp Timestamp::operator-(const Timestamp &ts) const {
Timestamp result(*this);
result.addIntern(-ts);
return result;
}
int Timestamp::frameDiff(const Timestamp &ts) const {
int delta = 0;
if (_secs != ts._secs)
delta = (_secs - ts._secs) * _framerate;
delta += _numFrames;
if (_framerate == ts._framerate) {
delta -= ts._numFrames;
} else {
// We need to multiply by the quotient of the two framerates.
// We cancel the GCD in this fraction to reduce the risk of
// overflows.
const uint g = Common::gcd(_framerate, ts._framerate);
const uint p = _framerate / g;
const uint q = ts._framerate / g;
delta -= ((long)ts._numFrames * p + q/2) / (long)q;
}
return delta / (int)_framerateFactor;
}
int Timestamp::msecsDiff(const Timestamp &ts) const {
return msecs() - ts.msecs();
}
int Timestamp::msecs() const {
// Note that _framerate is always divisible by 1000.
return _secs * 1000 + _numFrames / (_framerate / 1000);
}
} // End of namespace Audio
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