tek/src/core/midi.rs

use crate::core::*;

pub type MIDIMessage =
    Vec<u8>;

pub type MIDIChunk =
    [Vec<MIDIMessage>];

/// Add "all notes off" to the start of a buffer.
pub fn all_notes_off (output: &mut MIDIChunk) {
    let mut buf = vec![];
    let msg = MidiMessage::Controller { controller: 123.into(), value: 0.into() };
    let evt = LiveEvent::Midi { channel: 0.into(), message: msg };
    evt.write(&mut buf).unwrap();
    output[0].push(buf);
}

pub fn parse_midi_input (input: MidiIter) -> Box<dyn Iterator<Item=(usize, LiveEvent, &[u8])> + '_> {
    Box::new(input.map(|RawMidi { time, bytes }|(
        time as usize,
        LiveEvent::parse(bytes).unwrap(),
        bytes
    )))
}

/// Write to JACK port from output buffer (containing notes from sequence and/or monitor)
pub fn write_midi_output (writer: &mut ::jack::MidiWriter, output: &MIDIChunk, frames: usize) {
    for time in 0..frames {
        for event in output[time].iter() {
            writer.write(&::jack::RawMidi { time: time as u32, bytes: &event })
                .expect(&format!("{event:?}"));
        }
    }
}

/// (pulses, name)
pub const NOTE_DURATIONS: [(u16, &str);26] = [
    (1,    "1/384"),
    (2,    "1/192"),
    (3,    "1/128"),
    (4,    "1/96"),
    (6,    "1/64"),
    (8,    "1/48"),
    (12,   "1/32"),
    (16,   "1/24"),
    (24,   "1/16"),
    (32,   "1/12"),
    (48,   "1/8"),
    (64,   "1/6"),
    (96,   "1/4"),
    (128,  "1/3"),
    (192,  "1/2"),
    (256,  "2/3"),
    (384,  "1/1"),
    (512,  "4/3"),
    (576,  "3/2"),
    (768,  "2/1"),
    (1152, "3/1"),
    (1536, "4/1"),
    (2304, "6/1"),
    (3072, "8/1"),
    (3456, "9/1"),
    (6144, "16/1"),
];

pub fn prev_note_length (ppq: u16) -> u16 {
    for i in 1..=16 {
        let length = NOTE_DURATIONS[16-i].0;
        if length < ppq {
            return length
        }
    }
    ppq
}

pub fn next_note_length (ppq: u16) -> u16 {
    for (length, _) in &NOTE_DURATIONS {
        if *length > ppq {
            return *length
        }
    }
    ppq
}

pub fn ppq_to_name (ppq: u16) -> &'static str {
    for (length, name) in &NOTE_DURATIONS {
        if *length == ppq {
            return name
        }
    }
    ""
}