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use super::{
ChannelModeMsg, ChannelVoiceMsg, ParseError, ReceiverContext, SystemCommonMsg,
SystemExclusiveMsg, SystemRealTimeMsg,
};
/// The primary interface of this library. Used to encode MIDI messages.
#[derive(Debug, Clone, PartialEq)]
pub enum MidiMsg {
/// Channel-level messages that act on a voice, such as turning notes on and off.
ChannelVoice {
channel: Channel,
msg: ChannelVoiceMsg,
},
/// Like `ChannelVoice`, but with the first "status" byte of the message omitted.
/// When these "running status" messages are sent, the receiver must treat them
/// as implicitly referring to the previous "status" received.
///
/// For instance, if a `ChannelVoiceMsg::NoteOn` message is received, and then
/// the next message does not contain a status byte, it implicitly refers to a
/// `ChannelVoiceMsg::NoteOn`.
RunningChannelVoice {
channel: Channel,
msg: ChannelVoiceMsg,
},
/// Channel-level messages that should alter the mode of the receiver.
ChannelMode {
channel: Channel,
msg: ChannelModeMsg,
},
/// Like `RunningChannelVoice` but for `ChannelMode`
RunningChannelMode {
channel: Channel,
msg: ChannelModeMsg,
},
/// A fairly limited set of messages, generally for device synchronization.
SystemCommon { msg: SystemCommonMsg },
/// Another limited set of messages used for device synchronization.
SystemRealTime { msg: SystemRealTimeMsg },
/// The bulk of the MIDI spec lives here, in "Universal System Exclusive" messages.
/// Also the home of manufacturer-specific messages.
SystemExclusive { msg: SystemExclusiveMsg },
}
impl MidiMsg {
/// Turn a `MidiMsg` into a series of bytes.
pub fn to_midi(&self) -> Vec<u8> {
let mut r: Vec<u8> = vec![];
self.extend_midi(&mut r);
r
}
/// Turn a series of bytes into a `MidiMsg`.
///
/// Ok results return a MidiMsg and the number of bytes consumed from the input.
pub fn from_midi(m: &[u8]) -> Result<(Self, usize), ParseError> {
Self::from_midi_with_context(m, &mut ReceiverContext::default())
}
/// Turn a series of bytes into a `MidiMsg`, given a [`ReceiverContext`](crate::ReceiverContext).
///
/// Consecutive messages that relate to each other will be collapsed into one
/// `MidiMsg`. E.g. a `ChannelVoiceMsg::ControlChange` where the CC is the MSB and LSB
/// of `ControlChange::Volume` will turn into a single `ControlChange::Volume` with both
/// bytes turned into one. Use [`MidiMsg::from_midi_with_context_no_extensions`] to disable this
/// behavior.
///
/// The `ReceiverContext` is also used to track the current [`TimeCode`](crate::TimeCode)
/// as sent through [`SystemCommonMsg::TimeCodeQuarterFrame`](crate::SystemCommonMsg::TimeCodeQuarterFrame1)
/// messages, or [`UniversalRealTimeMsg::TimeCodeFull`](crate::UniversalRealTimeMsg::TimeCodeFull)
/// messages.
///
/// Ok results return a MidiMsg and the number of bytes consumed from the input.
pub fn from_midi_with_context(
m: &[u8],
ctx: &mut ReceiverContext,
) -> Result<(Self, usize), ParseError> {
Self::_from_midi_with_context(m, ctx, true)
}
/// Like [`MidiMsg::from_midi_with_context`] but does not turn multiple related consecutive messages
/// into one `MidiMsg`.
pub fn from_midi_with_context_no_extensions(
m: &[u8],
ctx: &mut ReceiverContext,
) -> Result<(Self, usize), ParseError> {
Self::_from_midi_with_context(m, ctx, false)
}
fn _from_midi_with_context(
m: &[u8],
ctx: &mut ReceiverContext,
allow_extensions: bool,
) -> Result<(Self, usize), ParseError> {
let (mut midi_msg, mut len) = match m.first() {
Some(b) => match b >> 4 {
0x8 | 0x9 | 0xA | 0xC | 0xD | 0xE => {
let (msg, len) = ChannelVoiceMsg::from_midi(m)?;
let channel = Channel::from_u8(b & 0x0F);
let midi_msg = Self::ChannelVoice { channel, msg };
ctx.previous_channel_message = Some(midi_msg.clone());
Ok((midi_msg, len))
}
0xB => {
// Could either be a Channel Mode or CC message
let channel = Channel::from_u8(b & 0x0F);
let (midi_msg, len) = if let Some(b2) = m.get(1) {
if b2 >= &120 {
let (msg, len) = ChannelModeMsg::from_midi(m)?;
(Self::ChannelMode { channel, msg }, len)
} else {
let (mut msg, len) = ChannelVoiceMsg::from_midi(m)?;
if allow_extensions {
// If we can interpret this message as an extension to the previous
// one, do it.
match ctx.previous_channel_message {
Some(Self::ChannelVoice {
channel: prev_channel,
msg: prev_msg,
}) => {
if channel == prev_channel
&& prev_msg.is_extensible()
&& msg.is_extension()
{
match prev_msg.maybe_extend(&msg) {
Ok(updated_msg) => {
msg = updated_msg;
}
_ => (),
}
}
}
_ => (),
}
}
(Self::ChannelVoice { channel, msg }, len)
}
} else {
return Err(ParseError::UnexpectedEnd);
};
ctx.previous_channel_message = Some(midi_msg.clone());
Ok((midi_msg, len))
}
0xF => {
if b & 0b00001111 == 0 {
let (msg, len) = SystemExclusiveMsg::from_midi(m, ctx)?;
Ok((Self::SystemExclusive { msg }, len))
} else if b & 0b00001000 == 0 {
let (msg, len) = SystemCommonMsg::from_midi(m, ctx)?;
Ok((Self::SystemCommon { msg }, len))
} else {
let (msg, len) = SystemRealTimeMsg::from_midi(m)?;
Ok((Self::SystemRealTime { msg }, len))
}
}
_ => {
if let Some(p) = &ctx.previous_channel_message {
match p {
Self::ChannelVoice {channel, msg: prev_msg} => {
let (mut msg, len) = ChannelVoiceMsg::from_midi_running(m, prev_msg)?;
if allow_extensions {
// If we can interpret this message as an extension to the previous
// one, do it.
if prev_msg.is_extensible()
&& msg.is_extension()
{
match prev_msg.maybe_extend(&msg) {
Ok(updated_msg) => {
msg = updated_msg;
}
_ => (),
}
}
}
Ok((Self::ChannelVoice { channel: *channel, msg}, len))
}
Self::ChannelMode {channel, ..} => {
let (msg, len) = ChannelModeMsg::from_midi_running(m)?;
Ok((Self::ChannelMode { channel: *channel, msg}, len))
}
_ => Err(ParseError::Invalid(format!("ReceiverContext::previous_channel_message may only be a ChannelMode or ChannelVoice message.")))
}
} else {
Err(ParseError::ContextlessRunningStatus)
}
}
},
None => Err(ParseError::UnexpectedEnd),
}?;
if allow_extensions {
// If this is an extensible message, try to extend it
loop {
if let Self::ChannelVoice { channel, msg } = midi_msg {
if msg.is_extensible() {
// Shadow the context;
let mut ctx = ctx.clone();
// Try to extend an extensible message
match Self::_from_midi_with_context(&m[len..], &mut ctx, false) {
Ok((
Self::ChannelVoice {
channel: next_channel,
msg: next_msg,
},
next_len,
)) => {
if channel == next_channel && next_msg.is_extension() {
match msg.maybe_extend(&next_msg) {
Ok(updated_msg) => {
midi_msg = Self::ChannelVoice {
channel,
msg: updated_msg,
};
len += next_len;
}
_ => break,
}
} else {
break;
}
}
_ => break,
}
} else {
break;
}
} else {
break;
}
}
}
Ok((midi_msg, len))
}
/// Turn a set of `MidiMsg`s into a series of bytes, with fewer allocations than
/// repeatedly concatenating the results of `to_midi`.
pub fn messages_to_midi(msgs: &[Self]) -> Vec<u8> {
let mut r: Vec<u8> = vec![];
for m in msgs.iter() {
m.extend_midi(&mut r);
}
r
}
/// Given a `Vec<u8>`, append this `MidiMsg` to it.
pub fn extend_midi(&self, v: &mut Vec<u8>) {
match self {
MidiMsg::ChannelVoice { channel, msg } => {
let p = v.len();
msg.extend_midi(v);
v[p] += *channel as u8;
match msg {
ChannelVoiceMsg::HighResNoteOff { .. }
| ChannelVoiceMsg::HighResNoteOn { .. } => {
v[p + 3] += *channel as u8;
}
_ => (),
}
}
MidiMsg::RunningChannelVoice { msg, .. } => msg.extend_midi_running(v),
MidiMsg::ChannelMode { channel, msg } => {
let p = v.len();
msg.extend_midi(v);
v[p] += *channel as u8;
}
MidiMsg::RunningChannelMode { msg, .. } => msg.extend_midi_running(v),
MidiMsg::SystemCommon { msg } => msg.extend_midi(v),
MidiMsg::SystemRealTime { msg } => msg.extend_midi(v),
MidiMsg::SystemExclusive { msg } => msg.extend_midi(v),
}
}
}
impl From<&MidiMsg> for Vec<u8> {
fn from(m: &MidiMsg) -> Vec<u8> {
m.to_midi()
}
}
/// The MIDI channel, 1-16. Used by [`MidiMsg`] and elsewhere.
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Channel {
Ch1,
Ch2,
Ch3,
Ch4,
Ch5,
Ch6,
Ch7,
Ch8,
Ch9,
Ch10,
Ch11,
Ch12,
Ch13,
Ch14,
Ch15,
Ch16,
}
impl Channel {
pub fn from_u8(x: u8) -> Self {
match x {
0 => Self::Ch1,
1 => Self::Ch2,
2 => Self::Ch3,
3 => Self::Ch4,
4 => Self::Ch5,
5 => Self::Ch6,
6 => Self::Ch7,
7 => Self::Ch8,
8 => Self::Ch9,
9 => Self::Ch10,
10 => Self::Ch11,
11 => Self::Ch12,
12 => Self::Ch13,
13 => Self::Ch14,
14 => Self::Ch15,
_ => Self::Ch16,
}
}
}