Rust Programming By Example

Getting the frame samples

The only remaining feature needed for our MP3 decoder is to be able to iterate over the samples. We'll first write a function to get the next sample:

fn next_sample<R: Read>(decoder: &mut Mp3Decoder<R>) -> Option<i16> {
    if decoder.current_frame.samples[0].len() == 0 {
        return None;
    }

    // getting the sample and converting it from fixed step to i16
    let sample = decoder.current_frame.samples[decoder.current_frame_channel]     [decoder.current_frame_sample_pos];
    let sample = sample.to_i32() + (1 << (28 - 16));
    let sample = if sample >= 0x10000000 { 0x10000000 - 1 } else if sample <=      -0x10000000 { -0x10000000 } else { sample };
    let sample = sample >> (28 + 1 - 16);
    let sample = sample as i16; decoder.current_frame_channel ...