diff --git a/src/buffer.rs b/src/buffer.rs index 92d4de8e..84c0c9fa 100644 --- a/src/buffer.rs +++ b/src/buffer.rs @@ -26,9 +26,9 @@ impl<'a> Buffer<'a> { } /// Iterate over the samples, returning a channel iterator for each sample. - pub fn iter_mut(&mut self) -> Samples<'_, 'a> { + pub fn iter_mut(&mut self) -> Samples<'a> { Samples { - buffers: &mut self.output_slices, + buffers: self.output_slices.as_mut_slice(), current_sample: 0, } } @@ -49,24 +49,20 @@ impl<'a> Buffer<'a> { /// An iterator over all samples in the buffer, yielding iterators over each channel for every /// sample. This iteration order offers good cache locality for per-sample access. -pub struct Samples<'outer, 'inner> { +pub struct Samples<'a> { /// The raw output buffers. - pub(self) buffers: &'outer mut [&'inner mut [f32]], + pub(self) buffers: *mut [&'a mut [f32]], pub(self) current_sample: usize, } -impl<'outer, 'inner> Iterator for Samples<'outer, 'inner> { - type Item = Channels<'outer, 'inner>; +impl<'a> Iterator for Samples<'a> { + type Item = Channels<'a>; fn next(&mut self) -> Option { - if self.current_sample < self.buffers[0].len() { - // SAFETY: We guarantee that each sample is only mutably borrowed once in the channels - // iterator - let buffers: &'outer mut _ = unsafe { &mut *(self.buffers as *mut _) }; + if self.current_sample < self.len() { let channels = Channels { - buffers, + buffers: self.buffers, current_sample: self.current_sample, - current_channel: 0, }; self.current_sample += 1; @@ -78,35 +74,56 @@ impl<'outer, 'inner> Iterator for Samples<'outer, 'inner> { } fn size_hint(&self) -> (usize, Option) { - let remaining = self.buffers[0].len() - self.current_sample; + let remaining = unsafe { (*self.buffers)[0].len() } - self.current_sample; (remaining, Some(remaining)) } } -impl<'outer, 'inner> ExactSizeIterator for Samples<'outer, 'inner> {} +impl<'a> ExactSizeIterator for Samples<'a> {} -/// An iterator over the channel data for a sample, yielded by [Samples]. -pub struct Channels<'outer, 'inner> { +/// Can construct iterators over actual iterator over the channel data for a sample, yielded by +/// [Samples]. +pub struct Channels<'a> { /// The raw output buffers. - pub(self) buffers: &'outer mut [&'inner mut [f32]], + pub(self) buffers: *mut [&'a mut [f32]], + pub(self) current_sample: usize, +} + +/// The actual iterator over the channel data for a sample, yielded by [Channels]. +pub struct ChannelsIter<'a> { + /// The raw output buffers. + pub(self) buffers: *mut [&'a mut [f32]], pub(self) current_sample: usize, pub(self) current_channel: usize, } -impl<'outer, 'inner> Iterator for Channels<'outer, 'inner> { - type Item = &'inner mut f32; +impl<'a> IntoIterator for Channels<'a> { + type Item = &'a mut f32; + type IntoIter = ChannelsIter<'a>; + + fn into_iter(self) -> Self::IntoIter { + ChannelsIter { + buffers: self.buffers, + current_sample: self.current_sample, + current_channel: 0, + } + } +} + +impl<'a> Iterator for ChannelsIter<'a> { + type Item = &'a mut f32; fn next(&mut self) -> Option { - if self.current_channel < self.buffers.len() { + if self.current_channel < self.len() { // SAFETY: These bounds have already been checked let sample = unsafe { - self.buffers + (*self.buffers) .get_unchecked_mut(self.current_channel) .get_unchecked_mut(self.current_sample) }; // SAFETY: It is not possible to have multiple mutable references to the same sample at // the same time - let sample: &'inner mut f32 = unsafe { &mut *(sample as *mut f32) }; + let sample: &'a mut f32 = unsafe { &mut *(sample as *mut f32) }; self.current_channel += 1; @@ -117,19 +134,29 @@ impl<'outer, 'inner> Iterator for Channels<'outer, 'inner> { } fn size_hint(&self) -> (usize, Option) { - let remaining = self.buffers.len() - self.current_channel; + let remaining = unsafe { (*self.buffers).len() } - self.current_channel; (remaining, Some(remaining)) } } -impl<'outer, 'inner> ExactSizeIterator for Channels<'outer, 'inner> {} +impl<'a> ExactSizeIterator for ChannelsIter<'a> {} + +impl Channels<'_> { + /// Get the number of channels. + pub fn len(&self) -> usize { + unsafe { (*self.buffers).len() } + } -impl<'outer, 'inner> Channels<'outer, 'inner> { /// A resetting iterator. This lets you iterate over the same channels multiple times. Otherwise /// you don't need to use this function as [Channels] already implements [Iterator]. - pub fn iter_mut(&mut self) -> &mut Self { - self.current_channel = 0; - self + pub fn iter_mut<'a: 'b, 'b>(&'a mut self) -> ChannelsIter<'b> { + // SAFETY: No two [ChannelIters] can exist at a time + let buffers: *mut [&'b mut [f32]] = unsafe { std::mem::transmute(self.buffers) }; + ChannelsIter { + buffers, + current_sample: self.current_sample, + current_channel: 0, + } } /// Access a sample by index. Useful when you would otehrwise iterate over this 'Channels' @@ -139,7 +166,7 @@ impl<'outer, 'inner> Channels<'outer, 'inner> { // SAFETY: The channel bound has already been checked unsafe { Some( - self.buffers + (*self.buffers) .get_mut(channel_index)? .get_unchecked_mut(self.current_sample), ) @@ -153,7 +180,7 @@ impl<'outer, 'inner> Channels<'outer, 'inner> { /// `channel_index` must be in the range `0..Self::len()`. #[inline] pub unsafe fn get_unchecked_mut(&mut self, channel_index: usize) -> &mut f32 { - self.buffers + (*self.buffers) .get_unchecked_mut(channel_index) .get_unchecked_mut(self.current_sample) }