game-toolkit-dosaudio 0.1.6

Emulated DOS-era sound hardware for Rust games: PC speaker, AdLib/OPL3, Sound Blaster 1 to 16, MPU-401 with General MIDI and MT-32, and Tandy PSG on one shared hardware clock
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69

// Copyright (C) 2021-2026 Geoff Hill <geoff@geoffhill.org>
// Copyright (C) 2003-2026 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 2.1 of the License, or (at
// your option) any later version. Read COPYING.LESSER.txt for details.

use super::midi::Event;
use std::boxed::Box;

const MIDI_QUEUE_SIZE: usize = 4096;
const MIDI_QUEUE_MASK: usize = 0xfff;

#[derive(Debug)]
pub struct MidiQueue {
    items: Box<[Option<Event>; MIDI_QUEUE_SIZE]>,
    given: usize,
    taken: usize,
}

impl MidiQueue {
    pub fn new() -> MidiQueue {
        const INIT: Option<Event> = None;
        MidiQueue {
            items: Box::new([INIT; MIDI_QUEUE_SIZE]),
            given: 0,
            taken: 0,
        }
    }

    pub fn push(&mut self, value: Event) -> bool {
        let (given, taken) = (self.given, self.taken);

        if given.wrapping_sub(taken) >= MIDI_QUEUE_SIZE {
            return false;
        }

        let slot = given & MIDI_QUEUE_MASK;
        // assert_eq!(self.items[slot], None);
        self.items[slot] = Some(value);
        self.given = given.wrapping_add(1);
        true
    }

    pub fn peek(&self) -> Option<&Event> {
        let (given, taken) = (self.given, self.taken);

        if given == taken {
            return None;
        }

        let slot = taken & MIDI_QUEUE_MASK;
        self.items[slot].as_ref()
    }

    pub fn pop(&mut self) -> Option<Event> {
        let (given, taken) = (self.given, self.taken);

        if given == taken {
            return None;
        }

        let slot = taken & MIDI_QUEUE_MASK;
        let value = self.items[slot].take();
        self.taken = taken.wrapping_add(1);
        value
    }
}