Make display processor buffer variable sized

Use const generics to make the display processor buffer defined by user.
Unfortunately the default const type inference makes working with this
clunky. See issue: rust-lang/rust#98931

src/main.rs

@@ -41,50 +41,51 @@ enum SubCommand {
 }
 
 fn passthrough() {
-    let _streams = hardware::setup_passthrough_processor(DisplayProcessor::new(true));
+    let display_processor: DisplayProcessor = DisplayProcessor::new(true);
+    let _streams = hardware::setup_passthrough_processor(display_processor);
     std::thread::park();
 }
 
 fn naive_pitch_shifter() {
+    let display_processor: DisplayProcessor = DisplayProcessor::new(true);
     let composed_processor = ComposedProcessor::new(
-        DisplayProcessor::new(true),
+        display_processor,
         Segmenter::new(NaivePitchShifter::new(1.2)),
     );
-    let composed_processor =
-        ComposedProcessor::new(composed_processor, DisplayProcessor::new(false));
+    let display_processor: DisplayProcessor = DisplayProcessor::new(false);
+    let composed_processor = ComposedProcessor::new(composed_processor, display_processor);
     let _streams = hardware::setup_passthrough_processor(composed_processor);
     std::thread::park();
 }
 
 fn high_pass_filter() {
-    let composed_processor = ComposedProcessor::new(
-        DisplayProcessor::new(true),
-        Segmenter::new(HighPassFilter::new()),
-    );
+    let display_processor: DisplayProcessor = DisplayProcessor::new(true);
     let composed_processor =
-        ComposedProcessor::new(composed_processor, DisplayProcessor::new(false));
+        ComposedProcessor::new(display_processor, Segmenter::new(HighPassFilter::new()));
+    let display_processor: DisplayProcessor = DisplayProcessor::new(false);
+    let composed_processor = ComposedProcessor::new(composed_processor, display_processor);
     let _streams = hardware::setup_passthrough_processor(composed_processor);
     std::thread::park();
 }
 
 fn low_pass_filter() {
-    let composed_processor = ComposedProcessor::new(
-        DisplayProcessor::new(true),
-        Segmenter::new(LowPassFilter::new()),
-    );
+    let display_processor: DisplayProcessor = DisplayProcessor::new(true);
     let composed_processor =
-        ComposedProcessor::new(composed_processor, DisplayProcessor::new(false));
+        ComposedProcessor::new(display_processor, Segmenter::new(LowPassFilter::new()));
+    let display_processor: DisplayProcessor = DisplayProcessor::new(false);
+    let composed_processor = ComposedProcessor::new(composed_processor, display_processor);
     let _streams = hardware::setup_passthrough_processor(composed_processor);
     std::thread::park();
 }
 
 fn frequency_domain_pitch_shifter() {
+    let display_processor: DisplayProcessor = DisplayProcessor::new(true);
     let composed_processor = ComposedProcessor::new(
-        DisplayProcessor::new(true),
+        display_processor,
         Segmenter::new(FrequencyDomainPitchShifter::new()),
     );
-    let composed_processor =
-        ComposedProcessor::new(composed_processor, DisplayProcessor::new(false));
+    let display_processor: DisplayProcessor = DisplayProcessor::new(false);
+    let composed_processor = ComposedProcessor::new(composed_processor, display_processor);
     let _streams = hardware::setup_passthrough_processor(composed_processor);
     std::thread::park();
 }
@@ -95,10 +96,10 @@ fn play() {
     let barrier = Arc::new(Barrier::new(2));
     let barrier_clone = barrier.clone();
     let once = std::sync::Once::new();
-
+    let display_processor: DisplayProcessor = DisplayProcessor::new(true);
     let pitch_halver = ComposedProcessor::new(
         Segmenter::new(FrequencyDomainPitchShifter::new()),
-        DisplayProcessor::new(true),
+        display_processor,
     );
 
     for t in (0..SAMPLE_RATE * 5).map(|x| x as f32 / SAMPLE_RATE as f32) {

src/signal_processing.rs

@@ -42,9 +42,9 @@ pub struct FrequencyDomainPitchShifter {
     scaling_ratio: f32,
 }
 
-pub struct DisplayProcessor {
+pub struct DisplayProcessor<const I: usize = BUFFER_SIZE> {
     buffer: SegQueue<f32>,
-    display_buffer: Mutex<Box<[f32]>>,
+    display_buffer: Mutex<[f32; I]>,
     buffer_index: AtomicUsize,
     signal_drawer: SignalDrawer,
 }
@@ -138,18 +138,18 @@ where
     }
 }
 
-impl DisplayProcessor {
+impl<const I: usize> DisplayProcessor<I> {
     pub fn new(should_clear_screen: bool) -> Self {
         Self {
             buffer: SegQueue::new(),
-            display_buffer: Mutex::new(Box::new([0.0; BUFFER_SIZE])),
+            display_buffer: Mutex::new([0.0; I]),
             buffer_index: AtomicUsize::new(0),
             signal_drawer: SignalDrawer::new(should_clear_screen),
         }
     }
 }
 
-impl StreamProcessor for DisplayProcessor {
+impl<const I: usize> StreamProcessor for DisplayProcessor<I> {
     fn push_sample(&self, sample: f32) {
         self.buffer.push(sample);
     }
@@ -159,9 +159,9 @@ impl StreamProcessor for DisplayProcessor {
         let mut buffer = self.display_buffer.lock().unwrap();
         buffer[self.buffer_index.load(Ordering::Relaxed)] = sample;
         self.buffer_index.fetch_add(1, Ordering::Relaxed);
-        if self.buffer_index.load(Ordering::Relaxed) >= BUFFER_SIZE {
+        if self.buffer_index.load(Ordering::Relaxed) >= I {
             self.buffer_index.swap(0, Ordering::Relaxed);
-            self.signal_drawer.draw_data(&buffer);
+            self.signal_drawer.draw_data(&*buffer);
         }
         Some(sample)
     }