fn position()

in src/backend/mod.rs [4977:5014]

• 35 lines of code
• 5 McCabe index (conditional complexity)

    fn position(&mut self) -> Result<u64> {
        let OutputCallbackTimingData {
            frames_queued,
            timestamp,
            buffer_size,
        } = self.output_callback_timing_data_read.read().clone();
        let total_output_latency_frames =
            u64::from(self.total_output_latency_frames.load(Ordering::SeqCst));
        // If output latency is available, take it into account. Otherwise, use the number of
        // frames played.
        let position = if total_output_latency_frames != 0 {
            if total_output_latency_frames > frames_queued {
                0
            } else {
                // Interpolate here to match other cubeb backends. Only return an interpolated time
                // if we've played enough frames. If the stream is paused, clamp the interpolated
                // number of frames to the buffer size.
                const NS2S: u64 = 1_000_000_000;
                let now = unsafe { mach_absolute_time() };
                let diff = now - timestamp;
                let interpolated_frames = cmp::min(
                    host_time_to_ns(self.context, diff)
                        * self.core_stream_data.output_stream_params.rate() as u64
                        / NS2S,
                    buffer_size,
                );
                (frames_queued - total_output_latency_frames) + interpolated_frames
            }
        } else {
            frames_queued
        };

        // Ensure mononicity of the clock even when changing output device.
        if position > self.prev_position {
            self.prev_position = position;
        }
        Ok(self.prev_position)
    }