Implement decoding Flac

Cargo.toml

@@ -9,6 +9,7 @@ repository = "https://github.com/tomaka/rodio"
 documentation = "http://tomaka.github.io/rodio/rodio/index.html"
 
 [dependencies]
+claxon = "0.3.0"
 cpal = "0.4.0"
 futures = "0.1.1"
 hound = "1.0.0"

README.md

@@ -9,6 +9,7 @@ Rust playback library.
  - Playback is handled by [cpal](https://github.com/tomaka/cpal).
  - WAV decoding is handled by [hound](https://github.com/ruud-v-a/hound).
  - Vorbis decoding is handled by [lewton](https://github.com/est31/lewton).
+ - Flac decoding is handled by [claxon](https://github.com/ruuda/claxon).
 
 ## [Documentation](http://tomaka.github.io/rodio/rodio/index.html)
 

examples/music_flac.rs

@@ -0,0 +1,13 @@
+extern crate rodio;
+
+use std::io::BufReader;
+
+fn main() {
+    let endpoint = rodio::get_default_endpoint().unwrap();
+    let sink = rodio::Sink::new(&endpoint);
+
+    let file = std::fs::File::open("examples/music.flac").unwrap();
+    sink.append(rodio::Decoder::new(BufReader::new(file)).unwrap());
+
+    sink.sleep_until_end();
+}

examples/music_ogg.rs

@@ -1,8 +1,6 @@
 extern crate rodio;
 
 use std::io::BufReader;
-use std::thread;
-use std::time::Duration;
 
 fn main() {
     let endpoint = rodio::get_default_endpoint().unwrap();
@@ -11,5 +9,5 @@ fn main() {
     let file = std::fs::File::open("examples/music.ogg").unwrap();
     sink.append(rodio::Decoder::new(BufReader::new(file)).unwrap());
 
-    thread::sleep(Duration::from_millis(60000));
+    sink.sleep_until_end();
 }

src/decoder/flac.rs

@@ -0,0 +1,115 @@
+use std::mem;
+use std::io::{Read, Seek, SeekFrom};
+use std::time::Duration;
+
+use Source;
+
+use claxon::FlacReader;
+
+/// Decoder for the Flac format.
+pub struct FlacDecoder<R>
+    where R: Read + Seek
+{
+    reader: FlacReader<R>,
+    current_block: Vec<i32>,
+    current_block_off: usize,
+    bits_per_sample: u32,
+    samples_rate: u32,
+    channels: u16,
+}
+
+impl<R> FlacDecoder<R>
+    where R: Read + Seek
+{
+    /// Attempts to decode the data as Flac.
+    pub fn new(mut data: R) -> Result<FlacDecoder<R>, R> {
+        if !is_flac(data.by_ref()) {
+            return Err(data);
+        }
+
+        let reader = FlacReader::new(data).unwrap();
+        let spec = reader.streaminfo();
+
+        Ok(FlacDecoder {
+            reader: reader,
+            current_block: Vec::with_capacity(spec.max_block_size as usize *
+                                              spec.channels as usize),
+            current_block_off: 0,
+            bits_per_sample: spec.bits_per_sample,
+            samples_rate: spec.sample_rate,
+            channels: spec.channels as u16,
+        })
+    }
+}
+
+impl<R> Source for FlacDecoder<R>
+    where R: Read + Seek
+{
+    #[inline]
+    fn get_current_frame_len(&self) -> Option<usize> {
+        None
+    }
+
+    #[inline]
+    fn get_channels(&self) -> u16 {
+        self.channels
+    }
+
+    #[inline]
+    fn get_samples_rate(&self) -> u32 {
+        self.samples_rate
+    }
+
+    #[inline]
+    fn get_total_duration(&self) -> Option<Duration> {
+        None
+    }
+}
+
+impl<R> Iterator for FlacDecoder<R>
+    where R: Read + Seek
+{
+    type Item = i16;
+
+    #[inline]
+    fn next(&mut self) -> Option<i16> {
+        loop {
+            if self.current_block_off < self.current_block.len() {
+                // Read from current block.
+                let raw_val = self.current_block[self.current_block_off];
+                self.current_block_off += 1;
+                let real_val = if self.bits_per_sample == 16 {
+                    raw_val as i16
+                } else if self.bits_per_sample < 16 {
+                    (raw_val << (16 - self.bits_per_sample)) as i16
+                } else {
+                    (raw_val >> (self.bits_per_sample - 16)) as i16
+                };
+                return Some(real_val as i16);
+            }
+
+            // Load the next block.
+            self.current_block_off = 0;
+            let buffer = mem::replace(&mut self.current_block, Vec::new());
+            match self.reader.blocks().read_next_or_eof(buffer) {
+                Ok(Some(block)) => self.current_block = block.into_buffer(),
+                _ => return None,
+            }
+        }
+    }
+}
+
+/// Returns true if the stream contains Flac data, then resets it to where it was.
+fn is_flac<R>(mut data: R) -> bool
+    where R: Read + Seek
+{
+    let stream_pos = data.seek(SeekFrom::Current(0)).unwrap();
+
+    if FlacReader::new(data.by_ref()).is_err() {
+        data.seek(SeekFrom::Start(stream_pos)).unwrap();
+        return false;
+    }
+
+    data.seek(SeekFrom::Start(stream_pos)).unwrap();
+    true
+}

src/decoder/mod.rs

@@ -6,12 +6,13 @@ use std::time::Duration;
 use Sample;
 use Source;
 
+mod flac;
 mod vorbis;
 mod wav;
 
 /// Source of audio samples from decoding a file.
 ///
-/// Supports WAV and Vorbis.
+/// Supports WAV, Vorbis and Flac.
 pub struct Decoder<R>(DecoderImpl<R>) where R: Read + Seek;
 
 enum DecoderImpl<R>
@@ -19,6 +20,7 @@ enum DecoderImpl<R>
 {
     Wav(wav::WavDecoder<R>),
     Vorbis(vorbis::VorbisDecoder<R>),
+    Flac(flac::FlacDecoder<R>),
 }
 
 impl<R> Decoder<R>
@@ -35,6 +37,13 @@ impl<R> Decoder<R>
             }
         };
 
+        let data = match flac::FlacDecoder::new(data) {
+            Err(data) => data,
+            Ok(decoder) => {
+                return Ok(Decoder(DecoderImpl::Flac(decoder)));
+            }
+        };
+
         if let Ok(decoder) = vorbis::VorbisDecoder::new(data) {
             return Ok(Decoder(DecoderImpl::Vorbis(decoder)));
         }
@@ -53,6 +62,7 @@ impl<R> Iterator for Decoder<R>
         match self.0 {
             DecoderImpl::Wav(ref mut source) => source.next().map(|s| s.to_f32()),
             DecoderImpl::Vorbis(ref mut source) => source.next().map(|s| s.to_f32()),
+            DecoderImpl::Flac(ref mut source) => source.next().map(|s| s.to_f32()),
         }
     }
 
@@ -61,6 +71,7 @@ impl<R> Iterator for Decoder<R>
         match self.0 {
             DecoderImpl::Wav(ref source) => source.size_hint(),
             DecoderImpl::Vorbis(ref source) => source.size_hint(),
+            DecoderImpl::Flac(ref source) => source.size_hint(),
         }
     }
 }
@@ -73,6 +84,7 @@ impl<R> Source for Decoder<R>
         match self.0 {
             DecoderImpl::Wav(ref source) => source.get_current_frame_len(),
             DecoderImpl::Vorbis(ref source) => source.get_current_frame_len(),
+            DecoderImpl::Flac(ref source) => source.get_current_frame_len(),
         }
     }
 
@@ -81,6 +93,7 @@ impl<R> Source for Decoder<R>
         match self.0 {
             DecoderImpl::Wav(ref source) => source.get_channels(),
             DecoderImpl::Vorbis(ref source) => source.get_channels(),
+            DecoderImpl::Flac(ref source) => source.get_channels(),
         }
     }
 
@@ -89,6 +102,7 @@ impl<R> Source for Decoder<R>
         match self.0 {
             DecoderImpl::Wav(ref source) => source.get_samples_rate(),
             DecoderImpl::Vorbis(ref source) => source.get_samples_rate(),
+            DecoderImpl::Flac(ref source) => source.get_samples_rate(),
         }
     }
 
@@ -97,6 +111,7 @@ impl<R> Source for Decoder<R>
         match self.0 {
             DecoderImpl::Wav(ref source) => source.get_total_duration(),
             DecoderImpl::Vorbis(ref source) => source.get_total_duration(),
+            DecoderImpl::Flac(ref source) => source.get_total_duration(),
         }
     }
 }

src/lib.rs

@@ -53,6 +53,7 @@
 
 #![cfg_attr(test, deny(missing_docs))]
 
+extern crate claxon;
 extern crate cpal;
 extern crate futures;
 extern crate hound;