456 lines
16 KiB
Rust
456 lines
16 KiB
Rust
use std::marker::PhantomData;
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/// The audio buffers used during processing. This contains the output audio output buffers with the
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/// inputs already copied to the outputs. You can either use the iterator adapters to conveniently
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/// and efficiently iterate over the samples, or you can do your own thing using the raw audio
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/// buffers.
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#[derive(Default)]
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pub struct Buffer<'a> {
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/// Contains slices for the plugin's outputs. You can't directly create a nested slice form
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/// apointer to pointers, so this needs to be preallocated in the setup call and kept around
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/// between process calls. And because storing a reference to this means a) that you need a lot
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/// of lifetime annotations everywhere and b) that at some point you need unsound lifetime casts
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/// because this `Buffers` either cannot have the same lifetime as the separately stored output
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/// buffers, and it also cannot be stored in a field next to it because that would mean
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/// containing mutable references to data stored in a mutex.
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output_slices: Vec<&'a mut [f32]>,
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}
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// Per-sample per-channel iterators
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/// An iterator over all samples in the buffer, yielding iterators over each channel for every
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/// sample. This iteration order offers good cache locality for per-sample access.
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pub struct SamplesIter<'slice, 'sample: 'slice> {
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/// The raw output buffers.
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pub(self) buffers: *mut [&'sample mut [f32]],
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pub(self) current_sample: usize,
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pub(self) _marker: PhantomData<&'slice mut [&'sample mut [f32]]>,
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}
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/// Can construct iterators over actual iterator over the channel data for a sample, yielded by
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/// [Samples]. Can be turned into an iterator, or [Channels::iter_mut()] can be used to iterate over
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/// the channel data multiple times, or more efficiently you can use [Channels::get_unchecked_mut()]
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/// to do the same thing.
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pub struct Channels<'slice, 'sample: 'slice> {
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/// The raw output buffers.
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pub(self) buffers: *mut [&'sample mut [f32]],
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pub(self) current_sample: usize,
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pub(self) _marker: PhantomData<&'slice mut [&'sample mut [f32]]>,
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}
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/// The actual iterator over the channel data for a sample, yielded by [Channels].
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pub struct ChannelsIter<'slice, 'sample: 'slice> {
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/// The raw output buffers.
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pub(self) buffers: *mut [&'sample mut [f32]],
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pub(self) current_sample: usize,
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pub(self) current_channel: usize,
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pub(self) _marker: PhantomData<&'slice mut [&'sample mut [f32]]>,
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}
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// Per-block per-channel per-sample iterators
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/// An iterator over all samples in the buffer, slicing over the sample-dimension with a maximum
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/// size of [Self::max_block_size]. See [Buffer::iter_blocks()]. Yields both the block and the
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/// offset from the start of the buffer.
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pub struct BlocksIter<'slice, 'sample: 'slice> {
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/// The raw output buffers.
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pub(self) buffers: *mut [&'sample mut [f32]],
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pub(self) max_block_size: usize,
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pub(self) current_block_start: usize,
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pub(self) _marker: PhantomData<&'slice mut [&'sample mut [f32]]>,
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}
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/// A block yielded by [BlocksIter]. Can be iterated over once or multiple times, and also supports
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/// direct access to the block's samples if needed.
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pub struct Block<'slice, 'sample: 'slice> {
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/// The raw output buffers.
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pub(self) buffers: *mut [&'sample mut [f32]],
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pub(self) current_block_start: usize,
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pub(self) current_block_end: usize,
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pub(self) _marker: PhantomData<&'slice mut [&'sample mut [f32]]>,
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}
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/// An iterator over all channels in a block yielded by [Block]. Analogous to [ChannelsIter] but for
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/// blocks.
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pub struct BlockChannelsIter<'slice, 'sample: 'slice> {
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/// The raw output buffers.
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pub(self) buffers: *mut [&'sample mut [f32]],
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pub(self) current_block_start: usize,
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pub(self) current_block_end: usize,
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pub(self) current_channel: usize,
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pub(self) _marker: PhantomData<&'slice mut [&'sample mut [f32]]>,
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}
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impl<'slice, 'sample> Iterator for SamplesIter<'slice, 'sample> {
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type Item = Channels<'slice, 'sample>;
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fn next(&mut self) -> Option<Self::Item> {
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if self.current_sample < unsafe { (*self.buffers)[0].len() } {
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let channels = Channels {
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buffers: self.buffers,
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current_sample: self.current_sample,
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_marker: self._marker,
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};
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self.current_sample += 1;
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Some(channels)
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} else {
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None
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}
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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let remaining = unsafe { (*self.buffers)[0].len() } - self.current_sample;
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(remaining, Some(remaining))
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}
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}
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impl<'slice, 'sample> Iterator for BlockChannelsIter<'slice, 'sample> {
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type Item = &'sample mut [f32];
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fn next(&mut self) -> Option<Self::Item> {
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if self.current_channel < unsafe { (*self.buffers).len() } {
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// SAFETY: These bounds have already been checked
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// SAFETY: It is also not possible to have multiple mutable references to the same
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// sample at the same time
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let slice = unsafe {
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(*self.buffers)
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.get_unchecked_mut(self.current_channel)
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.get_unchecked_mut(self.current_block_start..self.current_block_end)
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};
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self.current_channel += 1;
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Some(slice)
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} else {
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None
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}
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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let remaining = unsafe { (*self.buffers).len() } - self.current_channel;
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(remaining, Some(remaining))
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}
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}
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impl<'slice, 'sample> Iterator for BlocksIter<'slice, 'sample> {
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type Item = (usize, Block<'slice, 'sample>);
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fn next(&mut self) -> Option<Self::Item> {
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let buffer_len = unsafe { (*self.buffers)[0].len() };
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if self.current_block_start < buffer_len {
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let current_block_start = self.current_block_start;
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let current_block_end =
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(self.current_block_start + self.max_block_size).min(buffer_len);
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let block = Block {
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buffers: self.buffers,
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current_block_start,
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current_block_end,
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_marker: self._marker,
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};
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self.current_block_start += self.max_block_size;
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Some((current_block_start, block))
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} else {
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None
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}
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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let remaining = ((unsafe { (*self.buffers)[0].len() } - self.current_block_start) as f32
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/ self.max_block_size as f32)
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.ceil() as usize;
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(remaining, Some(remaining))
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}
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}
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impl<'slice, 'sample> Iterator for ChannelsIter<'slice, 'sample> {
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type Item = &'sample mut f32;
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fn next(&mut self) -> Option<Self::Item> {
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if self.current_channel < unsafe { (*self.buffers).len() } {
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// SAFETY: These bounds have already been checked
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// SAFETY: It is also not possible to have multiple mutable references to the same
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// sample at the same time
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let sample = unsafe {
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(*self.buffers)
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.get_unchecked_mut(self.current_channel)
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.get_unchecked_mut(self.current_sample)
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};
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self.current_channel += 1;
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Some(sample)
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} else {
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None
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}
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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let remaining = unsafe { (*self.buffers).len() } - self.current_channel;
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(remaining, Some(remaining))
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}
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}
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impl<'slice, 'sample> IntoIterator for Channels<'slice, 'sample> {
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type Item = &'sample mut f32;
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type IntoIter = ChannelsIter<'slice, 'sample>;
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fn into_iter(self) -> Self::IntoIter {
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ChannelsIter {
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buffers: self.buffers,
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current_sample: self.current_sample,
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current_channel: 0,
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_marker: self._marker,
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}
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}
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}
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impl<'slice, 'sample> IntoIterator for Block<'slice, 'sample> {
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type Item = &'sample mut [f32];
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type IntoIter = BlockChannelsIter<'slice, 'sample>;
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fn into_iter(self) -> Self::IntoIter {
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BlockChannelsIter {
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buffers: self.buffers,
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current_block_start: self.current_block_start,
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current_block_end: self.current_block_end,
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current_channel: 0,
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_marker: self._marker,
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}
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}
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}
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impl ExactSizeIterator for SamplesIter<'_, '_> {}
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impl ExactSizeIterator for ChannelsIter<'_, '_> {}
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impl ExactSizeIterator for BlocksIter<'_, '_> {}
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impl ExactSizeIterator for BlockChannelsIter<'_, '_> {}
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impl<'a> Buffer<'a> {
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/// Returns true if this buffer does not contain any samples.
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pub fn is_empty(&self) -> bool {
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self.output_slices.is_empty() || self.output_slices[0].is_empty()
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}
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/// Obtain the raw audio buffers.
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pub fn as_slice(&mut self) -> &mut [&'a mut [f32]] {
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&mut self.output_slices
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}
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/// Iterate over the samples, returning a channel iterator for each sample.
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pub fn iter_mut<'slice>(&'slice mut self) -> SamplesIter<'slice, 'a> {
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SamplesIter {
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buffers: self.output_slices.as_mut_slice(),
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current_sample: 0,
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_marker: PhantomData,
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}
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}
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/// Iterate over the buffer in blocks with the specified maximum size. The ideal maximum block
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/// size depends on the plugin in question, but 64 or 128 samples works for most plugins. Since
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/// the buffer's total size may not be cleanly divisble by the maximum size, the returned
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/// buffers may have any size in `[1, max_block_size]`. This is useful when using algorithms
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/// that work on entire blocks of audio, like those that would otherwise need to perform
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/// expensive per-sample branching or that can use per-sample SIMD as opposed to per-channel
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/// SIMD.
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///
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/// The parameter smoothers can also produce smoothed values for an entire block using
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/// [crate::Smoother::next_block()]. Before using this, you will need to call
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/// [crate::Plugin::initialize_block_smoothers()] with the same `max_block_size` in your
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/// initialization function first.
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///
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/// You can use this to obtain block-slices from a buffer so you can pass them to a libraryq:
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///
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/// ```ignore
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/// for block in buffer.iter_blocks(128) {
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/// let mut block_channels = block.into_iter();
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/// let stereo_slice = &[
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/// block_channels.next().unwrap(),
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/// block_channels.next().unwrap(),
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/// ];
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///
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/// // Do something cool with `stereo_slice`
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/// }
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/// ````
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pub fn iter_blocks<'slice>(&'slice mut self, max_block_size: usize) -> BlocksIter<'slice, 'a> {
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BlocksIter {
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buffers: self.output_slices.as_mut_slice(),
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max_block_size,
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current_block_start: 0,
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_marker: PhantomData,
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}
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}
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/// Access the raw output slice vector. This needs to be resized to match the number of output
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/// channels during the plugin's initialization. Then during audio processing, these slices
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/// should be updated to point to the plugin's audio buffers.
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///
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/// # Safety
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///
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/// The stored slices must point to live data when this object is passed to the plugins' process
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/// function. The rest of this object also assumes all channel lengths are equal. Panics will
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/// likely occur if this is not the case.
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pub unsafe fn with_raw_vec(&mut self, update: impl FnOnce(&mut Vec<&'a mut [f32]>)) {
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update(&mut self.output_slices);
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}
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}
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impl<'slice, 'sample> Channels<'slice, 'sample> {
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/// Get the number of channels.
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pub fn len(&self) -> usize {
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unsafe { (*self.buffers).len() }
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}
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/// A resetting iterator. This lets you iterate over the same channels multiple times. Otherwise
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/// you don't need to use this function as [Channels] already implements [Iterator].
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pub fn iter_mut(&mut self) -> ChannelsIter<'slice, 'sample> {
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ChannelsIter {
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buffers: self.buffers,
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current_sample: self.current_sample,
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current_channel: 0,
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_marker: self._marker,
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}
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}
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/// Access a sample by index. Useful when you would otherwise iterate over this 'Channels'
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/// iterator multiple times.
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#[inline]
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pub fn get_mut(&mut self, channel_index: usize) -> Option<&mut f32> {
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// SAFETY: The sample bound has already been checked
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unsafe {
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Some(
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(*self.buffers)
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.get_mut(channel_index)?
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.get_unchecked_mut(self.current_sample),
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)
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}
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}
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/// The same as [Self::get_mut], but without any bounds checking.
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///
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/// # Safety
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///
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/// `channel_index` must be in the range `0..Self::len()`.
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#[inline]
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pub unsafe fn get_unchecked_mut(&mut self, channel_index: usize) -> &mut f32 {
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(*self.buffers)
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.get_unchecked_mut(channel_index)
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.get_unchecked_mut(self.current_sample)
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}
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}
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impl<'slice, 'sample> Block<'slice, 'sample> {
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/// Get the number of samples (not channels) in the block.
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pub fn len(&self) -> usize {
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self.current_block_end - self.current_block_start
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}
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/// A resetting iterator. This lets you iterate over the same block multiple times. Otherwise
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/// you don't need to use this function as [Block] already implements [Iterator]. You can also
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/// use the direct accessor functions on this block instead.
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pub fn iter_mut(&mut self) -> BlockChannelsIter<'slice, 'sample> {
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BlockChannelsIter {
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buffers: self.buffers,
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current_block_start: self.current_block_start,
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current_block_end: self.current_block_end,
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current_channel: 0,
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_marker: self._marker,
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}
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}
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/// Access a channel by index. Useful when you would otherwise iterate over this [Block]
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/// multiple times.
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#[inline]
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pub fn get_mut(&mut self, channel_index: usize) -> Option<&mut [f32]> {
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// SAFETY: The block bound has already been checked
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unsafe {
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Some(
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(*self.buffers)
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.get_mut(channel_index)?
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.get_unchecked_mut(self.current_block_start..self.current_block_end),
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)
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}
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}
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/// The same as [Self::get_mut], but without any bounds checking.
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///
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/// # Safety
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///
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/// `channel_index` must be in the range `0..Self::len()`.
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#[inline]
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pub unsafe fn get_unchecked_mut(&mut self, channel_index: usize) -> &mut [f32] {
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(*self.buffers)
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.get_unchecked_mut(channel_index)
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.get_unchecked_mut(self.current_block_start..self.current_block_end)
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}
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}
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#[cfg(any(miri, test))]
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mod miri {
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use super::*;
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#[test]
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fn repeated_access() {
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let mut real_buffers = vec![vec![0.0; 512]; 2];
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let mut buffer = Buffer::default();
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unsafe {
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buffer.with_raw_vec(|output_slices| {
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let (first_channel, other_channels) = real_buffers.split_at_mut(1);
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*output_slices = vec![&mut first_channel[0], &mut other_channels[0]];
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})
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};
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for samples in buffer.iter_mut() {
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for sample in samples {
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*sample += 0.001;
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}
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}
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for mut samples in buffer.iter_mut() {
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for _ in 0..2 {
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for sample in samples.iter_mut() {
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*sample += 0.001;
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}
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}
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}
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assert_eq!(real_buffers[0][0], 0.003);
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}
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#[test]
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fn repeated_slices() {
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let mut real_buffers = vec![vec![0.0; 512]; 2];
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let mut buffer = Buffer::default();
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unsafe {
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buffer.with_raw_vec(|output_slices| {
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let (first_channel, other_channels) = real_buffers.split_at_mut(1);
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*output_slices = vec![&mut first_channel[0], &mut other_channels[0]];
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})
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};
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// These iterators should not alias
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let mut blocks = buffer.iter_blocks(16);
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let (_block1_offset, block1) = blocks.next().unwrap();
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let (_block2_offset, block2) = blocks.next().unwrap();
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for channel in block1 {
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for sample in channel.iter_mut() {
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*sample += 0.001;
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}
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}
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for channel in block2 {
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for sample in channel.iter_mut() {
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*sample += 0.001;
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}
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}
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for i in 0..32 {
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assert_eq!(real_buffers[0][i], 0.001);
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}
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for i in 32..48 {
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assert_eq!(real_buffers[0][i], 0.0);
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}
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}
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}
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