See what happens if channels and sample_rate are options.

This is a major refactor touching all the parts.
The idea behind it is that for the exceptional case of `Empty` we can supply None to either and otherwise we either have supplied values or some "sane" defaults available to use

Author: DivineGod

benches/resampler.rs

@@ -17,7 +17,7 @@ fn no_resampling(bencher: Bencher) {
             (source.channels(), source.sample_rate(), source)
         })
         .bench_values(|(channels, sample_rate, source)| {
-            UniformSourceIterator::<_, i16>::new(source, channels, sample_rate)
+            UniformSourceIterator::<_, i16>::new(source, channels.unwrap(), sample_rate.unwrap())
                 .for_each(divan::black_box_drop)
         })
 }
@@ -36,7 +36,7 @@ fn resample_to(bencher: Bencher, target_sample_rate: u32) {
             (source.channels(), source)
         })
         .bench_values(|(channels, source)| {
-            UniformSourceIterator::<_, i16>::new(source, channels, target_sample_rate)
+            UniformSourceIterator::<_, i16>::new(source, channels.unwrap(), target_sample_rate)
                 .for_each(divan::black_box_drop)
         })
 }

benches/shared.rs

@@ -30,12 +30,12 @@ impl<T: rodio::Sample> Source for TestSource<T> {
         None // forever
     }
 
-    fn channels(&self) -> u16 {
-        self.channels
+    fn channels(&self) -> Option<u16> {
+        Some(self.channels)
     }
 
-    fn sample_rate(&self) -> u32 {
-        self.sample_rate
+    fn sample_rate(&self) -> Option<u32> {
+        Some(self.sample_rate)
     }
 
     fn total_duration(&self) -> Option<Duration> {
@@ -54,8 +54,8 @@ impl TestSource<i16> {
             .take_duration(duration);
 
         TestSource {
-            channels: sound.channels(),
-            sample_rate: sound.sample_rate(),
+            channels: sound.channels().unwrap(),
+            sample_rate: sound.sample_rate().unwrap(),
             total_duration: duration,
             samples: sound.into_iter().collect::<Vec<_>>().into_iter(),
         }

src/buffer.rs

@@ -74,13 +74,13 @@ where
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
-        self.channels
+    fn channels(&self) -> Option<u16> {
+        Some(self.channels)
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
-        self.sample_rate
+    fn sample_rate(&self) -> Option<u32> {
+        Some(self.sample_rate)
     }
 
     #[inline]
@@ -95,14 +95,16 @@ where
     /// This jumps in memory till the sample for `pos`.
     #[inline]
     fn try_seek(&mut self, pos: Duration) -> Result<(), SeekError> {
-        let curr_channel = self.pos % self.channels() as usize;
-        let new_pos = pos.as_secs_f32() * self.sample_rate() as f32 * self.channels() as f32;
+        let curr_channel = self.pos % self.channels().unwrap() as usize;
+        let new_pos = pos.as_secs_f32()
+            * self.sample_rate().unwrap() as f32
+            * self.channels().unwrap() as f32;
         // saturate pos at the end of the source
         let new_pos = new_pos as usize;
         let new_pos = new_pos.min(self.data.len());
 
         // make sure the next sample is for the right channel
-        let new_pos = new_pos.next_multiple_of(self.channels() as usize);
+        let new_pos = new_pos.next_multiple_of(self.channels().unwrap() as usize);
         let new_pos = new_pos - curr_channel;
 
         self.pos = new_pos;

src/conversions/channels.rs

@@ -30,10 +30,7 @@ where
         to: cpal::ChannelCount,
     ) -> ChannelCountConverter<I> {
         assert!(to >= 1);
-        let from = match from {
-            0 => to,
-            n => n,
-        };
+        assert!(from >= 1);
 
         ChannelCountConverter {
             input,
@@ -183,9 +180,18 @@ mod test {
     }
 
     #[test]
+    #[should_panic]
     fn zero_input() {
         let input = vec![1u16, 2, 3, 4, 5, 6];
-        let output = ChannelCountConverter::new(input.into_iter(), 0, 3);
-        assert_eq!(output.len(), 6);
+        // Panics because from is 0
+        let _output = ChannelCountConverter::new(input.into_iter(), 0, 3);
+    }
+
+    #[test]
+    #[should_panic]
+    fn zero_output() {
+        let input = vec![1u16, 2, 3, 4, 5, 6];
+        // Panics because to is 0
+        let _output = ChannelCountConverter::new(input.into_iter(), 3, 0);
     }
 }

src/conversions/sample_rate.rs

@@ -356,7 +356,7 @@ mod test {
 
             let to = SampleRate(to);
             let source = SineWave::new(freq).take_duration(d);
-            let from = SampleRate(source.sample_rate());
+            let from = SampleRate(source.sample_rate().unwrap());
 
             let resampled =
                 SampleRateConverter::new(source, from, to, 1);

src/decoder/flac.rs

@@ -64,13 +64,13 @@ where
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
-        self.channels
+    fn channels(&self) -> Option<u16> {
+        Some(self.channels)
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
-        self.sample_rate
+    fn sample_rate(&self) -> Option<u32> {
+        Some(self.sample_rate)
     }
 
     #[inline]

src/decoder/mod.rs

@@ -118,7 +118,7 @@ impl<R: Read + Seek> DecoderImpl<R> {
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
+    fn channels(&self) -> Option<u16> {
         match self {
             #[cfg(all(feature = "wav", not(feature = "symphonia-wav")))]
             DecoderImpl::Wav(source) => source.channels(),
@@ -130,12 +130,12 @@ impl<R: Read + Seek> DecoderImpl<R> {
             DecoderImpl::Mp3(source) => source.channels(),
             #[cfg(feature = "symphonia")]
             DecoderImpl::Symphonia(source) => source.channels(),
-            DecoderImpl::None(_) => 0,
+            DecoderImpl::None(_) => None, // FIX-ME? I changed this from `0` to `None` instead of `Some(0)`
         }
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
+    fn sample_rate(&self) -> Option<u32> {
         match self {
             #[cfg(all(feature = "wav", not(feature = "symphonia-wav")))]
             DecoderImpl::Wav(source) => source.sample_rate(),
@@ -147,7 +147,7 @@ impl<R: Read + Seek> DecoderImpl<R> {
             DecoderImpl::Mp3(source) => source.sample_rate(),
             #[cfg(feature = "symphonia")]
             DecoderImpl::Symphonia(source) => source.sample_rate(),
-            DecoderImpl::None(_) => 1,
+            DecoderImpl::None(_) => Some(1),
         }
     }
 
@@ -418,11 +418,11 @@ where
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
+    fn channels(&self) -> Option<u16> {
         self.0.channels()
     }
 
-    fn sample_rate(&self) -> u32 {
+    fn sample_rate(&self) -> Option<u32> {
         self.0.sample_rate()
     }
 
@@ -516,12 +516,12 @@ where
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
+    fn channels(&self) -> Option<u16> {
         self.0.channels()
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
+    fn sample_rate(&self) -> Option<u32> {
         self.0.sample_rate()
     }
 

src/decoder/symphonia.rs

@@ -159,13 +159,13 @@ impl Source for SymphoniaDecoder {
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
-        self.spec.channels.count() as u16
+    fn channels(&self) -> Option<u16> {
+        Some(self.spec.channels.count() as u16)
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
-        self.spec.rate
+    fn sample_rate(&self) -> Option<u32> {
+        Some(self.spec.rate)
     }
 
     #[inline]
@@ -188,7 +188,7 @@ impl Source for SymphoniaDecoder {
         };
 
         // make sure the next sample is for the right channel
-        let to_skip = self.current_frame_offset % self.channels() as usize;
+        let to_skip = self.current_frame_offset % self.channels().unwrap() as usize;
 
         let seek_res = self
             .format
@@ -285,7 +285,7 @@ impl SymphoniaDecoder {
         let decoded = decoded.map_err(SeekError::Decoding)?;
         decoded.spec().clone_into(&mut self.spec);
         self.buffer = SymphoniaDecoder::get_buffer(decoded, &self.spec);
-        self.current_frame_offset = samples_to_pass as usize * self.channels() as usize;
+        self.current_frame_offset = samples_to_pass as usize * self.channels().unwrap() as usize;
         Ok(())
     }
 }

src/decoder/vorbis.rs

@@ -62,13 +62,13 @@ where
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
-        self.stream_reader.ident_hdr.audio_channels as u16
+    fn channels(&self) -> Option<u16> {
+        Some(self.stream_reader.ident_hdr.audio_channels as u16)
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
-        self.stream_reader.ident_hdr.audio_sample_rate
+    fn sample_rate(&self) -> Option<u32> {
+        Some(self.stream_reader.ident_hdr.audio_sample_rate)
     }
 
     #[inline]

src/decoder/wav.rs

@@ -115,13 +115,13 @@ where
     }
 
     #[inline]
-    fn channels(&self) -> u16 {
-        self.channels
+    fn channels(&self) -> Option<u16> {
+        Some(self.channels)
     }
 
     #[inline]
-    fn sample_rate(&self) -> u32 {
-        self.sample_rate
+    fn sample_rate(&self) -> Option<u32> {
+        Some(self.sample_rate)
     }
 
     #[inline]
@@ -133,18 +133,18 @@ where
     fn try_seek(&mut self, pos: Duration) -> Result<(), SeekError> {
         let file_len = self.reader.reader.duration();
 
-        let new_pos = pos.as_secs_f32() * self.sample_rate() as f32;
+        let new_pos = pos.as_secs_f32() * self.sample_rate as f32;
         let new_pos = new_pos as u32;
         let new_pos = new_pos.min(file_len); // saturate pos at the end of the source
 
         // make sure the next sample is for the right channel
-        let to_skip = self.reader.samples_read % self.channels() as u32;
+        let to_skip = self.reader.samples_read % self.channels as u32;
 
         self.reader
             .reader
             .seek(new_pos)
             .map_err(SeekError::HoundDecoder)?;
-        self.reader.samples_read = new_pos * self.channels() as u32;
+        self.reader.samples_read = new_pos * self.channels as u32;
 
         for _ in 0..to_skip {
             self.next();