int Beats::numBeatsInRange(double dStartSample, double dEndSample) {
double dLastCountedBeat = 0.0;
int iBeatsCounter;
for (iBeatsCounter = 1; dLastCountedBeat < dEndSample; iBeatsCounter++) {
dLastCountedBeat = findNthBeat(dStartSample, iBeatsCounter);
if (dLastCountedBeat == -1) {
break;
}
}
return iBeatsCounter - 2;
};
double Beats::findNBeatsFromSample(double fromSample, double beats) const {
double nthBeat;
double prevBeat;
double nextBeat;
if (!findPrevNextBeats(fromSample, &prevBeat, &nextBeat)) {
return fromSample;
}
double fromFractionBeats = (fromSample - prevBeat) / (nextBeat - prevBeat);
double beatsFromPrevBeat = fromFractionBeats + beats;
int fullBeats = static_cast<int>(beatsFromPrevBeat);
double fractionBeats = beatsFromPrevBeat - fullBeats;
// Add the length between this beat and the fullbeats'th beat
// to the end position
if (fullBeats > 0) {
nthBeat = findNthBeat(nextBeat, fullBeats);
} else {
nthBeat = findNthBeat(prevBeat, fullBeats - 1);
}
if (nthBeat == -1) {
return fromSample;
}
// Add the fraction of the beat
if (fractionBeats != 0) {
nextBeat = findNthBeat(nthBeat, 2);
if (nextBeat == -1) {
return fromSample;
}
nthBeat += (nextBeat - nthBeat) * fractionBeats;
}
return nthBeat;
};
// This could be implemented in the Beats Class itself.
// If necessary, the child class can redefine it.
double BeatGrid::findPrevBeat(double dSamples) const {
return findNthBeat(dSamples, -1);
}
// This could be implemented in the Beats Class itself.
// If necessary, the child class can redefine it.
double BeatGrid::findNextBeat(double dSamples) const {
return findNthBeat(dSamples, +1);
}