Struct Channel

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pub struct Channel<'a, T> { /* private fields */ }

Expand description

The buffer of a single channel.

This doesn’t provide direct access to the underlying buffer, but rather allows us to copy data usinga number of utility functions.

Implementations§

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impl<'a, T> Channel<'a, T>

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pub fn linear(buf: &'a [T]) -> Self

Construct a linear channel buffer.

The buffer provided as-is constitutes the frames of the channel.

§Examples

use rotary::Channel;

let buf = &mut [1, 3, 5, 7];
let channel = Channel::linear(buf);

assert_eq!(channel[1], 3);
assert_eq!(channel[2], 5);

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pub fn interleaved(buf: &'a [T], channels: usize, channel: usize) -> Self

Construct an interleaved channel buffer.

The provided buffer must be the complete buffer, which includes all other channels. The provided channels argument is the total number of channels in this buffer, and channel indicates which specific channel this buffer belongs to.

Note that this is typically not used directly, but instead through an abstraction which makes sure to provide the correct parameters.

§Examples

use rotary::Channel;

let buf = &[1, 2, 3, 4, 5, 6, 7, 8];
let channel = Channel::interleaved(buf, 2, 1);

assert_eq!(channel[1], 4);
assert_eq!(channel[2], 6);

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pub fn frames(&self) -> usize

Access the number of frames on the current channel.

§Examples

use rotary::Buf;

fn test(buf: &dyn Buf<f32>) {
    let left = buf.channel(0);
    let right = buf.channel(1);

    assert_eq!(left.frames(), 16);
    assert_eq!(right.frames(), 16);
}

test(&rotary::dynamic![[0.0; 16]; 2]);
test(&rotary::sequential![[0.0; 16]; 2]);
test(&rotary::interleaved![[0.0; 16]; 2]);

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pub fn iter(self) -> Iter<'a, T>

Construct an iterator over the channel.

§Examples

use rotary::{Buf as _, BufMut as _};

let mut left = rotary::interleaved![[0.0f32; 4]; 2];
let mut right = rotary::dynamic![[0.0f32; 4]; 2];

for (l, r) in left.channel_mut(0).iter_mut().zip(right.channel_mut(0)) {
    *l = 1.0;
    *r = 1.0;
}

assert!(left.channel(0).iter().eq(right.channel(0).iter()));

assert_eq!(left.as_slice(), &[1.0, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0, 0.0]);
assert_eq!(&right[0], &[1.0, 1.0, 1.0, 1.0]);
assert_eq!(&right[1], &[0.0, 0.0, 0.0, 0.0]);

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pub fn as_ref(&self) -> Channel<'_, T>

Construct a new Channel reference with a lifetime associated with the current channel instance instead of the underlying buffer.

Most of the time it is not necessary to use this, since Channel implements Copy and its lifetime would coerce to any compatible lifetime. This method is currently just here for completeness sake.

Both of these work equally well:

use rotary::Channel;

struct Foo<'a> {
    channel: Channel<'a, i16>,
}

impl<'a> Foo<'a> {
    fn channel(&self) -> Channel<'_, i16> {
        self.channel.as_ref()
    }

    fn coerced_channel(&self) -> Channel<'_, i16> {
        self.channel
    }
}

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pub fn skip(self, n: usize) -> Self

Construct a channel buffer where the first n frames are skipped.

§Examples

use rotary::{Buf as _, BufMut as _};

let mut from = rotary::interleaved![[0.0f32; 4]; 2];
*from.frame_mut(0, 2).unwrap() = 1.0;
*from.frame_mut(0, 3).unwrap() = 1.0;

let mut to = rotary::interleaved![[0.0f32; 4]; 2];

to.channel_mut(0).copy_from(from.channel(0).skip(2));
assert_eq!(to.as_slice(), &[1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0]);

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pub fn tail(self, n: usize) -> Self

Construct a channel buffer where the last n frames are included.

§Examples

use rotary::{Buf as _, BufMut as _};

let from = rotary::interleaved![[1.0f32; 4]; 2];
let mut to = rotary::interleaved![[0.0f32; 4]; 2];

to.channel_mut(0).as_mut().tail(2).copy_from(from.channel(0));
assert_eq!(to.as_slice(), &[0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0]);

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pub fn limit(self, limit: usize) -> Self

Limit the channel bufferto limit number of frames.

§Examples

use rotary::{Buf as _, BufMut as _};

let from = rotary::interleaved![[1.0f32; 4]; 2];
let mut to = rotary::interleaved![[0.0f32; 4]; 2];

to.channel_mut(0).copy_from(from.channel(0).limit(2));
assert_eq!(to.as_slice(), &[1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0]);

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pub fn chunk(self, n: usize, len: usize) -> Self

Construct a range of frames corresponds to the chunk with len and position n.

Which is the range n * len .. n * len + len.

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pub fn chunks(&self, chunk: usize) -> usize

How many chunks of the given size can you divide buf into.

This includes one extra chunk even if the chunk doesn’t divide the frame length evenly.

§Examples

use rotary::Buf;

fn test(buf: &dyn Buf<f32>) {
    let left = buf.channel(0);
    let right = buf.channel(1);

    assert_eq!(left.chunks(4), 4);
    assert_eq!(right.chunks(4), 4);

    assert_eq!(left.chunks(6), 3);
    assert_eq!(right.chunks(6), 3);
}

test(&rotary::dynamic![[0.0; 16]; 2]);
test(&rotary::sequential![[0.0; 16]; 2]);
test(&rotary::interleaved![[0.0; 16]; 2]);

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pub fn copy_into_slice(&self, out: &mut [T])
where T: Copy,

Copy into the given slice of output.

§Examples

use rotary::Buf;

fn test(buf: &dyn Buf<f32>) {
    let channel = buf.channel(0);

    let mut buf = vec![0.0; 16];
    channel.copy_into_slice(&mut buf[..]);

    assert!(buf.iter().all(|f| *f == 1.0));
}

test(&rotary::dynamic![[1.0; 16]; 2]);
test(&rotary::sequential![[1.0; 16]; 2]);
test(&rotary::interleaved![[1.0; 16]; 2]);

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pub fn copy_into_iter<'out, I>(&self, iter: I)
where I: IntoIterator<Item = &'out mut T>, T: 'out + Copy,

Copy into the given iterator.

§Examples

use rotary::Buf;

fn test(buf: &dyn Buf<f32>) {
    let channel = buf.channel(0);

    let mut buf = vec![0.0; 16];

    // Copy into every other position in `buf`.
    channel.copy_into_iter(buf.iter_mut().step_by(2));

    for (n, f) in buf.into_iter().enumerate() {
        if n % 2 == 0 {
            assert_eq!(f, 1.0);
        } else {
            assert_eq!(f, 0.0);
        }
    }
}

test(&rotary::dynamic![[1.0; 16]; 2]);
test(&rotary::sequential![[1.0; 16]; 2]);
test(&rotary::interleaved![[1.0; 16]; 2]);