Struct ChannelMut

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

Expand description

The mutable 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> ChannelMut<'a, T>

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

Construct a mutable linear channel buffer.

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

§Examples

use rotary::ChannelMut;

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

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

channel[1] *= 4;

assert_eq!(buf, &[1, 12, 5, 7]);

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

Construct a mutable 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::ChannelMut;

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

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

channel[1] *= 4;

assert_eq!(buf, &[1, 2, 3, 16, 5, 6, 7, 8]);

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pub fn into_ref(self) -> Channel<'a, T>

Convert the current mutable channel into a Channel with the lifetime matching the underlying buffer.

This is required in order to fully convert a ChannelMut into a Channel with the lifetime associated with the buffer, because if we only use as_ref we’ll actually be creating a reference to the mutable buffer instead.

§Examples

use rotary::{Channel, ChannelMut};

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

impl<'a> Foo<'a> {
    fn into_channel(self) -> Channel<'a, i16> {
        self.channel.into_ref()
    }
}

In contrast, this doesn’t compile:

use rotary::{Channel, ChannelMut};

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

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

With the following error:

   error[E0515]: cannot return value referencing local data `self.channel`
   --> test.rs:11:9
    |
 11 |         self.channel.as_ref()
    |         ------------^^^^^^^^^
    |         |
    |         returns a value referencing data owned by the current function
    |         `self.channel` is borrowed here

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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.

§Examples

use rotary::{Channel, ChannelMut};

let buf = &mut [1, 2, 3, 4];
let channel = ChannelMut::linear(buf);

let channel1 = channel.as_ref();
let channel2 = channel1; // Channel is Copy.

assert_eq!(channel1[0], channel2[0]);

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pub fn as_mut(&mut self) -> ChannelMut<'_, T>

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

Reborrowing like this is sometimes necessary, like if you want to pass an instance of ChannelMut directly into another function instead of borrowing it:

use rotary::{BufMut, ChannelMut};

fn takes_channel_mut(mut channel: ChannelMut<'_, i16>) {
    channel[1] = 42;
}

let mut buffer = rotary::interleaved![[0; 4]; 2];
let mut channel = buffer.channel_mut(1);

takes_channel_mut(channel.as_mut());

assert_eq!(channel[1], 42);

Without the reborrow, we would end up moving the channel:

use rotary::{BufMut, ChannelMut};

fn takes_channel_mut(mut channel: ChannelMut<'_, i16>) {
    channel[1] = 42;
}

let mut buffer = rotary::interleaved![[0; 4]; 2];
let mut channel = buffer.channel_mut(1);

takes_channel_mut(channel);

assert_eq!(channel[1], 42);

Causing the following error:

   error[E0382]: borrow of moved value: `channel`
   --> test.rs:10:12
    |
 10 | let mut channel = buffer.channel_mut(1);
    |     ----------- move occurs because `channel` has type `ChannelMut<'_, i16>`,
    |                 which does not implement the `Copy` trait
 11 |
 12 | takes_channel_mut(channel);
    |                   ------- value moved here
 13 |
 14 | assert_eq!(channel[1], 42);
    |            ^^^^^^^ value borrowed here after move

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pub fn frames(&self) -> usize

The number of frames in the buffer.

§Examples

use rotary::BufMut;

fn test(buf: &dyn BufMut<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 chunks(&self, chunk: usize) -> usize

The number of chunks that can fit with the given size.

§Examples

use rotary::BufMut;

fn test(buf: &dyn BufMut<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 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 iter_mut(self) -> IterMut<'a, T>

Construct a mutable 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 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 buffer = rotary::Interleaved::with_topology(2, 4);

buffer.channel_mut(0).skip(2).copy_from_slice(&[1.0, 1.0]);

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

§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).chunk(1, 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]);

§Examples

use rotary::Buf;

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

    let mut buf = vec![0.0; 4];
    channel.chunk(3, 4).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_from_slice(&mut self, buf: &[T])
where T: Copy,

Copy from the given slice.

§Examples

use rotary::BufMut;

fn test(buf: &mut dyn BufMut<f32>) {
    buf.channel_mut(0).copy_from_slice(&[1.0; 4][..]);

    let mut out = vec![0.0; 8];
    buf.channel(0).copy_into_slice(&mut out);

    assert_eq!(out, vec![1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0]);
}

test(&mut rotary::dynamic![[0.0; 8]; 2]);
test(&mut rotary::sequential![[0.0; 8]; 2]);
test(&mut rotary::interleaved![[0.0; 8]; 2]);

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pub fn copy_from_iter(&mut self, iter: I)
where I: IntoIterator<Item = T>,

Copy a chunked destination from an iterator.

§Examples

use rotary::BufMut;

fn test(buf: &mut dyn BufMut<f32>) {
    buf.channel_mut(0).skip(2).copy_from_iter(vec![1.0; 4]);

    let mut out = vec![0.0; 8];
    buf.channel(0).copy_into_slice(&mut out);

    assert_eq!(out, vec![0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0]);
}

test(&mut rotary::dynamic![[0.0; 8]; 2]);
test(&mut rotary::sequential![[0.0; 8]; 2]);
test(&mut rotary::interleaved![[0.0; 8]; 2]);

use rotary::BufMut;

fn test(buf: &mut dyn BufMut<f32>) {
    buf.channel_mut(0).skip(2).chunk(0, 2).copy_from_iter(vec![1.0; 4]);

    let mut out = vec![0.0; 8];
    buf.channel(0).copy_into_slice(&mut out);

    assert_eq!(out, vec![0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0]);
}

test(&mut rotary::dynamic![[0.0; 8]; 2]);
test(&mut rotary::sequential![[0.0; 8]; 2]);
test(&mut rotary::interleaved![[0.0; 8]; 2]);

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pub fn copy_from(&mut self, from: Channel<'_, T>)
where T: Copy,

Copy this channel from another.

§Examples

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

let from = rotary::dynamic![[1.0f32; 4]; 2];
let mut to = rotary::interleaved![[0.0f32; 4]; 3];

to.channel_mut(0).copy_from(from.channel(1));
assert_eq!(to.as_slice(), &[1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0]);

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pub fn translate_from(&mut self, from: Channel<'_, U>)
where U: Copy, T: Translate,

Translate this channel from another.

This will translate each sample in the channel through the appropriate Translate implementation.

This is used for converting a buffer containing one type of sample into another.

§Examples

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

let from = rotary::dynamic![[u16::MAX; 4]; 2];
let mut to = rotary::interleaved![[0.0f32; 4]; 3];

to.channel_mut(0).translate_from(from.channel(1));
assert_eq!(to.as_slice(), &[1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0]);

Trait Implementations§

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impl<'a, T: Debug> Debug for ChannelMut<'a, T>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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impl<T> Index<usize> for ChannelMut<'_, T>

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type Output = T

The returned type after indexing.

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fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation. Read more

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impl<T> IndexMut<usize> for ChannelMut<'_, T>

Get a mutable reference to the frame at the given index.

§Panics

Panics if the given frame is out of bounds for this channel.

See frames.

§Examples

use rotary::BufMut;

fn test(buf: &mut dyn BufMut<f32>) {
    buf.channel_mut(0)[1] = 1.0;
    buf.channel_mut(0)[7] = 1.0;

    let mut out = vec![0.0; 8];
    buf.channel(0).copy_into_slice(&mut out);

    assert_eq!(out, vec![0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0]);
}

test(&mut rotary::dynamic![[0.0; 8]; 2]);
test(&mut rotary::sequential![[0.0; 8]; 2]);
test(&mut rotary::interleaved![[0.0; 8]; 2]);