public static Interval operator +(Interval interval1, Interval interval2)
{
int absoluteNumber = interval1._absoluteNumber + interval2._absoluteNumber;
int semitones = (interval1.Semitones + interval2.Semitones) % SemitonesPerOctave;
IntervalNumber number = (IntervalNumber)Math.Abs(absoluteNumber % NumbersPerOctave);
IntervalQuality quality;
if (number.IsPerfect())
{
quality = IntervalQuality.Perfect;
semitones -= GetSemitones(number, quality, 0);
}
else
{
quality = IntervalQuality.Major;
semitones -= GetSemitones(number, quality, 0);
if (semitones < 0)
{
quality = IntervalQuality.Minor;
semitones++;
}
}
if (semitones > 0)
{
quality = IntervalQuality.Augmented;
}
else if (semitones < 0)
{
quality = IntervalQuality.Diminished;
}
return(new Interval(absoluteNumber, quality, (sbyte)Math.Abs(semitones)));
}
private static int GetSemitones(IntervalNumber number, IntervalQuality quality, sbyte multiplicity)
{
int semitones = s_numberToSemitones[number - IntervalNumber.Unison];
if (quality == IntervalQuality.Minor || quality == IntervalQuality.Diminished && !number.IsPerfect())
{
semitones--;
}
if (multiplicity > 0)
{
if (quality == IntervalQuality.Augmented)
{
semitones += multiplicity;
}
else
{
semitones -= multiplicity;
}
}
return(semitones);
}