audio 0.2.1

A crate for working with audio in Rust
Documentation 
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use core::ptr;

/// Utility functions to copy a channel in-place in a sequential audio buffer
/// from one place to another.
///
/// # Safety
///
/// Caller has to ensure that the `data` pointer points to sequential memory
/// with the correct topology and initialized frame count.
pub(crate) unsafe fn copy_channels_sequential<T>(
    data: ptr::NonNull<T>,
    channels: usize,
    frames: usize,
    from: usize,
    to: usize,
) where
    T: Copy,
{
    assert! {
        from < channels,
        "copy from channel {} is out of bounds 0-{}",
        from,
        channels
    };
    assert! {
        to < channels,
        "copy to channel {} which is out of bounds 0-{}",
        to,
        channels
    };

    if from != to {
        let from = data.as_ptr().add(from * frames);
        let to = data.as_ptr().add(to * frames);
        ptr::copy_nonoverlapping(from, to, frames);
    }
}

/// Utility functions to copy a channel in-place in an interleaved audio buffer
/// from one place to another.
///
/// # Safety
///
/// Caller has to ensure that the `data` pointer points to interleaved memory
/// with the correct topology and initialized frame count.
pub(crate) unsafe fn copy_channels_interleaved<T>(
    data: ptr::NonNull<T>,
    channels: usize,
    frames: usize,
    from: usize,
    to: usize,
) where
    T: Copy,
{
    assert! {
        from < channels,
        "copy from channel {} is out of bounds 0-{}",
        from,
        channels
    };
    assert! {
        to < channels,
        "copy to channel {} which is out of bounds 0-{}",
        to,
        channels
    };

    if from != to {
        // Safety: We're making sure not to access any mutable buffers which
        // are not initialized.
        for n in 0..frames {
            let from = data.as_ptr().add(from + channels * n) as *const _;
            let to = data.as_ptr().add(to + channels * n);
            let f = ptr::read(from);
            ptr::write(to, f);
        }
    }
}