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
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117

use std;
use std::ops::{Deref, DerefMut};

/// An interleaved PCM buffer yielded by either an input or output stream processing function.
#[derive(Debug)]
pub struct Buffer<S = f32> {
    pub(crate) interleaved_samples: Box<[S]>,
    pub(crate) channels: usize,
    pub(crate) sample_rate: u32,
}

/// An iterator yielding each frame in some Buffer.
///
/// A "frame" is a sample from each channel of audio at a single moment in time.
#[derive(Clone, Debug)]
pub struct Frames<'a, S: 'a> {
    chunks: std::slice::Chunks<'a, S>,
}

/// An iterator yielding mutable references to each frame in some Buffer.
///
/// A frame is a sample from each channel of audio at a single moment in time.
#[derive(Debug)]
pub struct FramesMut<'a, S: 'a> {
    chunks: std::slice::ChunksMut<'a, S>,
}

impl<S> Buffer<S> {
    /// The default number of frames per buffer.
    ///
    /// This can be overridden by specifying your own buffer size using the
    /// `stream::output::Builder::buffer_size` builder method.
    pub const DEFAULT_LEN_FRAMES: usize = 64;

    /// The sampling rate of the audio frames stored within the buffer.
    pub fn sample_rate(&self) -> u32 {
        self.sample_rate
    }

    /// The number of channels of audio per-frame within the buffer.
    pub fn channels(&self) -> usize {
        self.channels
    }

    /// The length of the buffer as a number of audio frames (i.e. len / channels).
    pub fn len_frames(&self) -> usize {
        self.interleaved_samples.len() / self.channels
    }

    /// Produce an iterator yielding each frame from the buffer in order.
    pub fn frames(&self) -> Frames<S> {
        let chunks = self.interleaved_samples.chunks(self.channels);
        Frames { chunks }
    }

    pub fn frames_mut(&mut self) -> FramesMut<S> {
        let chunks = self.interleaved_samples.chunks_mut(self.channels);
        FramesMut { chunks }
    }
}

impl<S> Deref for Buffer<S> {
    type Target = [S];
    fn deref(&self) -> &Self::Target {
        &self.interleaved_samples
    }
}

impl<S> DerefMut for Buffer<S> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.interleaved_samples
    }
}

impl<'a, S> Iterator for Frames<'a, S> {
    type Item = &'a [S];
    fn next(&mut self) -> Option<Self::Item> {
        self.chunks.next()
    }
    fn size_hint(&self) -> (usize, Option<usize>) {
        self.chunks.size_hint()
    }
}

impl<'a, S> Iterator for FramesMut<'a, S> {
    type Item = &'a mut [S];
    fn next(&mut self) -> Option<Self::Item> {
        self.chunks.next()
    }
    fn size_hint(&self) -> (usize, Option<usize>) {
        self.chunks.size_hint()
    }
}

impl<'a, S> ExactSizeIterator for Frames<'a, S> {
    fn len(&self) -> usize {
        self.chunks.len()
    }
}

impl<'a, S> ExactSizeIterator for FramesMut<'a, S> {
    fn len(&self) -> usize {
        self.chunks.len()
    }
}

impl<'a, S> DoubleEndedIterator for Frames<'a, S> {
    fn next_back(&mut self) -> Option<Self::Item> {
        self.chunks.next_back()
    }
}

impl<'a, S> DoubleEndedIterator for FramesMut<'a, S> {
    fn next_back(&mut self) -> Option<Self::Item> {
        self.chunks.next_back()
    }
}