src/decoder.rs at main · tsiry-sandratraina.com/tunein-cli

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radio rust tokio web-radio command-line-tool tui
tunein-cli / src / decoder.rs
at main 2.2 kB view raw
  1use std::time::Duration;
  2use std::{io::Read, sync::mpsc::Sender};
  3
  4use minimp3::{Decoder, Frame};
  5use rodio::Source;
  6
  7pub struct Mp3Decoder<R>
  8where
  9    R: Read,
 10{
 11    decoder: Decoder<R>,
 12    current_frame: Frame,
 13    current_frame_offset: usize,
 14    tx: Option<Sender<Frame>>,
 15}
 16
 17impl<R> Mp3Decoder<R>
 18where
 19    R: Read,
 20{
 21    pub fn new(mut data: R, tx: Option<Sender<Frame>>) -> Result<Self, R> {
 22        if !is_mp3(data.by_ref()) {
 23            return Err(data);
 24        }
 25        let mut decoder = Decoder::new(data);
 26        let current_frame = decoder.next_frame().unwrap();
 27
 28        Ok(Mp3Decoder {
 29            decoder,
 30            current_frame,
 31            current_frame_offset: 0,
 32            tx,
 33        })
 34    }
 35}
 36
 37impl<R> Source for Mp3Decoder<R>
 38where
 39    R: Read,
 40{
 41    #[inline]
 42    fn current_frame_len(&self) -> Option<usize> {
 43        Some(self.current_frame.data.len())
 44    }
 45
 46    #[inline]
 47    fn channels(&self) -> u16 {
 48        self.current_frame.channels as _
 49    }
 50
 51    #[inline]
 52    fn sample_rate(&self) -> u32 {
 53        self.current_frame.sample_rate as _
 54    }
 55
 56    #[inline]
 57    fn total_duration(&self) -> Option<Duration> {
 58        None
 59    }
 60}
 61
 62impl<R> Iterator for Mp3Decoder<R>
 63where
 64    R: Read,
 65{
 66    type Item = i16;
 67
 68    #[inline]
 69    fn next(&mut self) -> Option<i16> {
 70        if self.current_frame_offset == self.current_frame.data.len() {
 71            match self.decoder.next_frame() {
 72                Ok(frame) => {
 73                    if let Some(tx) = &self.tx {
 74                        if tx.send(frame.clone()).is_err() {
 75                            return None;
 76                        }
 77                    }
 78                    self.current_frame = frame
 79                }
 80                _ => return None,
 81            }
 82            self.current_frame_offset = 0;
 83        }
 84
 85        let v = self.current_frame.data[self.current_frame_offset];
 86        self.current_frame_offset += 1;
 87
 88        Some(v)
 89    }
 90}
 91
 92/// Returns true if the stream contains mp3 data, then resets it to where it was.
 93fn is_mp3<R>(mut data: R) -> bool
 94where
 95    R: Read,
 96{
 97    let mut decoder = Decoder::new(data.by_ref());
 98    let ok = decoder.next_frame().is_ok();
 99    ok
100}