public static async Task <ChordFinderResultSet> FindChordsAsync(IChordFinderOptions chordFinderOptions, CancellationToken cancelToken)
{
if (null == chordFinderOptions)
{
throw new ArgumentNullException(nameof(chordFinderOptions));
}
InternalNote root = NoteUtils.ToInternalNote(chordFinderOptions.RootNote);
IChordQuality chordQuality = chordFinderOptions.ChordQuality;
InternalNote[] notesInChord = NamedInterval.GetNotes(root, chordQuality.Intervals);
ChordFinderResultSet results = new ChordFinderResultSet(chordFinderOptions);
if (cancelToken.IsCancellationRequested)
{
return(results);
}
await FindAllChordsAsync(results, null, notesInChord, 0, chordFinderOptions, cancelToken);
return(results);
}
private static async Task FindAllChordsAsync(ChordFinderResultSet results, NoteNode noteNode, InternalNote[] targetNotes, int str, IChordFinderOptions chordFinderOptions, CancellationToken cancelToken)
{
if (cancelToken.IsCancellationRequested)
{
return;
}
IInstrument instrument = chordFinderOptions.Instrument;
if (str == instrument.NumStrings) // Build a chord result
{
int[] marks = new int[instrument.NumStrings];
NoteNode nn = noteNode;
str--;
bool[] hasNotes = new bool[targetNotes.Length];
// Walk back up the tree to set the marks on the result and flag each target note
while (null != nn)
{
marks[str] = nn.Fret;
for (int i = 0; i < targetNotes.Length; i++)
{
if (nn.Note == targetNotes[i])
{
hasNotes[i] = true;
}
}
nn = nn.Parent;
str--;
}
InternalNote rootNote = NoteUtils.ToInternalNote(chordFinderOptions.RootNote);
// Add result if it had all the target notes
bool valid = true;
for (int i = 0; i < hasNotes.Length; i++)
{
// Validate:
// 1. All notes when !AllowRootlessChords
// 2. Non-root notes only when AllowRootlessChords
if (!chordFinderOptions.AllowRootlessChords ||
(chordFinderOptions.AllowRootlessChords && targetNotes[i] != rootNote))
{
valid = valid && hasNotes[i];
}
}
if (valid)
{
results.AddResult(marks);
}
}
else // Keep building the tree
{
// Look at the muted string
if (chordFinderOptions.AllowMutedStrings)
{
NoteNode muted = new NoteNode
{
Parent = noteNode
};
await FindAllChordsAsync(results, muted, targetNotes, str + 1, chordFinderOptions, cancelToken);
}
// Look at all the notes on the string
int startingFret = chordFinderOptions.AllowOpenStrings ? 0 : 1;
for (int fret = startingFret; fret <= chordFinderOptions.MaxFret; fret++)
{
InternalNote note = NoteUtils.Shift(chordFinderOptions.Tuning.RootNotes[str].InternalNote, fret);
// See if the note is a target note
for (int i = 0; i < targetNotes.Length; i++)
{
// If it's a target note add it and search on the next string
if (note == targetNotes[i])
{
NoteNode child = new NoteNode(fret, note, noteNode);
await FindAllChordsAsync(results, child, targetNotes, str + 1, chordFinderOptions, cancelToken);
break;
}
}
}
}
}
internal ChordFinderResult(ChordFinderResultSet parent, int[] marks)
{
Parent = parent ?? throw new ArgumentNullException(nameof(parent));
Marks = marks ?? throw new ArgumentNullException(nameof(marks));
}
