9c781bd381
This implements the changes described at #370. This commit implements only the `null` and `alsa` backends - the rest will be implemented in follow-up commits. Closes #370.
1070 lines
34 KiB
Rust
1070 lines
34 KiB
Rust
extern crate alsa_sys as alsa;
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extern crate libc;
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use crate::{
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BackendSpecificError, BuildStreamError, ChannelCount, Data, DefaultStreamConfigError,
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DeviceNameError, DevicesError, PauseStreamError, PlayStreamError, SampleFormat, SampleRate,
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StreamError, SupportedStreamConfig, SupportedStreamConfigRange, SupportedStreamConfigsError,
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};
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use std::sync::Arc;
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use std::thread::{self, JoinHandle};
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use std::vec::IntoIter as VecIntoIter;
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use std::{cmp, ffi, io, ptr};
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use traits::{DeviceTrait, HostTrait, StreamTrait};
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pub use self::enumerate::{default_input_device, default_output_device, Devices};
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pub type SupportedInputConfigs = VecIntoIter<SupportedStreamConfigRange>;
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pub type SupportedOutputConfigs = VecIntoIter<SupportedStreamConfigRange>;
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mod enumerate;
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/// The default linux, dragonfly and freebsd host type.
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#[derive(Debug)]
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pub struct Host;
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impl Host {
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pub fn new() -> Result<Self, crate::HostUnavailable> {
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Ok(Host)
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}
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}
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impl HostTrait for Host {
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type Devices = Devices;
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type Device = Device;
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fn is_available() -> bool {
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// Assume ALSA is always available on linux/dragonfly/freebsd.
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true
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}
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fn devices(&self) -> Result<Self::Devices, DevicesError> {
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Devices::new()
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}
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fn default_input_device(&self) -> Option<Self::Device> {
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default_input_device()
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}
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fn default_output_device(&self) -> Option<Self::Device> {
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default_output_device()
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}
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}
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impl DeviceTrait for Device {
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type SupportedInputConfigs = SupportedInputConfigs;
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type SupportedOutputConfigs = SupportedOutputConfigs;
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type Stream = Stream;
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fn name(&self) -> Result<String, DeviceNameError> {
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Device::name(self)
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}
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fn supported_input_configs(
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&self,
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) -> Result<Self::SupportedInputConfigs, SupportedStreamConfigsError> {
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Device::supported_input_configs(self)
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}
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fn supported_output_configs(
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&self,
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) -> Result<Self::SupportedOutputConfigs, SupportedStreamConfigsError> {
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Device::supported_output_configs(self)
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}
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fn default_input_config(&self) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
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Device::default_input_config(self)
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}
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fn default_output_config(&self) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
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Device::default_output_config(self)
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}
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fn build_input_stream_raw<D, E>(
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&self,
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conf: &SupportedStreamConfig,
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data_callback: D,
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error_callback: E,
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) -> Result<Self::Stream, BuildStreamError>
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where
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D: FnMut(&Data) + Send + 'static,
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E: FnMut(StreamError) + Send + 'static,
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{
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let stream_inner = self.build_stream_inner(conf, alsa::SND_PCM_STREAM_CAPTURE)?;
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let stream = Stream::new_input(Arc::new(stream_inner), data_callback, error_callback);
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Ok(stream)
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}
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fn build_output_stream_raw<D, E>(
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&self,
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conf: &SupportedStreamConfig,
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data_callback: D,
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error_callback: E,
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) -> Result<Self::Stream, BuildStreamError>
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where
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D: FnMut(&mut Data) + Send + 'static,
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E: FnMut(StreamError) + Send + 'static,
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{
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let stream_inner = self.build_stream_inner(conf, alsa::SND_PCM_STREAM_PLAYBACK)?;
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let stream = Stream::new_output(Arc::new(stream_inner), data_callback, error_callback);
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Ok(stream)
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}
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}
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struct TriggerSender(libc::c_int);
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struct TriggerReceiver(libc::c_int);
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impl TriggerSender {
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fn wakeup(&self) {
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let buf = 1u64;
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let ret = unsafe { libc::write(self.0, &buf as *const u64 as *const _, 8) };
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assert!(ret == 8);
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}
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}
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impl TriggerReceiver {
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fn clear_pipe(&self) {
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let mut out = 0u64;
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let ret = unsafe { libc::read(self.0, &mut out as *mut u64 as *mut _, 8) };
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assert_eq!(ret, 8);
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}
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}
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fn trigger() -> (TriggerSender, TriggerReceiver) {
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let mut fds = [0, 0];
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match unsafe { libc::pipe(fds.as_mut_ptr()) } {
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0 => (TriggerSender(fds[1]), TriggerReceiver(fds[0])),
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_ => panic!("Could not create pipe"),
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}
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}
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impl Drop for TriggerSender {
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fn drop(&mut self) {
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unsafe {
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libc::close(self.0);
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}
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}
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}
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impl Drop for TriggerReceiver {
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fn drop(&mut self) {
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unsafe {
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libc::close(self.0);
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}
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}
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}
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#[derive(Clone, Debug, PartialEq, Eq)]
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pub struct Device(String);
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impl Device {
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fn build_stream_inner(
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&self,
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conf: &SupportedStreamConfig,
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stream_type: alsa::snd_pcm_stream_t,
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) -> Result<StreamInner, BuildStreamError> {
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let name = ffi::CString::new(self.0.clone()).expect("unable to clone device");
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let handle = unsafe {
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let mut handle = ptr::null_mut();
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match alsa::snd_pcm_open(
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&mut handle,
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name.as_ptr(),
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stream_type,
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alsa::SND_PCM_NONBLOCK,
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) {
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-16 /* determined empirically */ => return Err(BuildStreamError::DeviceNotAvailable),
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-22 => return Err(BuildStreamError::InvalidArgument),
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e => if let Err(description) = check_errors(e) {
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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}
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handle
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};
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let can_pause = unsafe {
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let hw_params = HwParams::alloc();
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set_hw_params_from_format(handle, &hw_params, conf)
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.map_err(|description| BackendSpecificError { description })?;
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alsa::snd_pcm_hw_params_can_pause(hw_params.0) == 1
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};
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let (buffer_len, period_len) = unsafe {
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set_sw_params_from_format(handle, conf)
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.map_err(|description| BackendSpecificError { description })?
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};
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if let Err(desc) = check_errors(unsafe { alsa::snd_pcm_prepare(handle) }) {
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let description = format!("could not get handle: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let num_descriptors = {
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let num_descriptors = unsafe { alsa::snd_pcm_poll_descriptors_count(handle) };
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if num_descriptors == 0 {
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let description = "poll descriptor count for stream was 0".to_string();
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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num_descriptors as usize
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};
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let stream_inner = StreamInner {
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channel: handle,
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sample_format: conf.sample_format,
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num_descriptors,
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num_channels: conf.channels as u16,
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buffer_len,
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period_len,
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can_pause,
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};
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if let Err(desc) = check_errors(unsafe { alsa::snd_pcm_start(handle) }) {
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let description = format!("could not start stream: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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Ok(stream_inner)
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}
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#[inline]
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fn name(&self) -> Result<String, DeviceNameError> {
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Ok(self.0.clone())
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}
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unsafe fn supported_configs(
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&self,
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stream_t: alsa::snd_pcm_stream_t,
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) -> Result<VecIntoIter<SupportedStreamConfigRange>, SupportedStreamConfigsError> {
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let mut handle = ptr::null_mut();
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let device_name = match ffi::CString::new(&self.0[..]) {
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Ok(name) => name,
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Err(err) => {
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let description = format!("failed to retrieve device name: {}", err);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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};
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match alsa::snd_pcm_open(
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&mut handle,
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device_name.as_ptr() as *const _,
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stream_t,
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alsa::SND_PCM_NONBLOCK,
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) {
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-2 |
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-16 /* determined empirically */ => return Err(SupportedStreamConfigsError::DeviceNotAvailable),
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-22 => return Err(SupportedStreamConfigsError::InvalidArgument),
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e => if let Err(description) = check_errors(e) {
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let err = BackendSpecificError { description };
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return Err(err.into())
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}
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}
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let hw_params = HwParams::alloc();
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match check_errors(alsa::snd_pcm_hw_params_any(handle, hw_params.0)) {
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Err(description) => {
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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Ok(_) => (),
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};
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// TODO: check endianess
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const FORMATS: [(SampleFormat, alsa::snd_pcm_format_t); 3] = [
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//SND_PCM_FORMAT_S8,
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//SND_PCM_FORMAT_U8,
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(SampleFormat::I16, alsa::SND_PCM_FORMAT_S16_LE),
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//SND_PCM_FORMAT_S16_BE,
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(SampleFormat::U16, alsa::SND_PCM_FORMAT_U16_LE),
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//SND_PCM_FORMAT_U16_BE,
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//SND_PCM_FORMAT_S24_LE,
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//SND_PCM_FORMAT_S24_BE,
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//SND_PCM_FORMAT_U24_LE,
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//SND_PCM_FORMAT_U24_BE,
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//SND_PCM_FORMAT_S32_LE,
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//SND_PCM_FORMAT_S32_BE,
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//SND_PCM_FORMAT_U32_LE,
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//SND_PCM_FORMAT_U32_BE,
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(SampleFormat::F32, alsa::SND_PCM_FORMAT_FLOAT_LE),
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//SND_PCM_FORMAT_FLOAT_BE,
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//SND_PCM_FORMAT_FLOAT64_LE,
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//SND_PCM_FORMAT_FLOAT64_BE,
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//SND_PCM_FORMAT_IEC958_SUBFRAME_LE,
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//SND_PCM_FORMAT_IEC958_SUBFRAME_BE,
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//SND_PCM_FORMAT_MU_LAW,
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//SND_PCM_FORMAT_A_LAW,
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//SND_PCM_FORMAT_IMA_ADPCM,
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//SND_PCM_FORMAT_MPEG,
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//SND_PCM_FORMAT_GSM,
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//SND_PCM_FORMAT_SPECIAL,
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//SND_PCM_FORMAT_S24_3LE,
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//SND_PCM_FORMAT_S24_3BE,
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//SND_PCM_FORMAT_U24_3LE,
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//SND_PCM_FORMAT_U24_3BE,
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//SND_PCM_FORMAT_S20_3LE,
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//SND_PCM_FORMAT_S20_3BE,
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//SND_PCM_FORMAT_U20_3LE,
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//SND_PCM_FORMAT_U20_3BE,
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//SND_PCM_FORMAT_S18_3LE,
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//SND_PCM_FORMAT_S18_3BE,
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//SND_PCM_FORMAT_U18_3LE,
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//SND_PCM_FORMAT_U18_3BE,
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];
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let mut supported_formats = Vec::new();
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for &(sample_format, alsa_format) in FORMATS.iter() {
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if alsa::snd_pcm_hw_params_test_format(handle, hw_params.0, alsa_format) == 0 {
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supported_formats.push(sample_format);
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}
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}
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let mut min_rate = 0;
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_rate_min(
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hw_params.0,
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&mut min_rate,
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ptr::null_mut(),
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)) {
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let description = format!("unable to get minimum supported rate: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let mut max_rate = 0;
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_rate_max(
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hw_params.0,
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&mut max_rate,
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ptr::null_mut(),
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)) {
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let description = format!("unable to get maximum supported rate: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let sample_rates = if min_rate == max_rate
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|| alsa::snd_pcm_hw_params_test_rate(handle, hw_params.0, min_rate + 1, 0) == 0
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{
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vec![(min_rate, max_rate)]
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} else {
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const RATES: [libc::c_uint; 13] = [
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5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000, 64000, 88200, 96000, 176400,
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192000,
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];
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let mut rates = Vec::new();
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for &rate in RATES.iter() {
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if alsa::snd_pcm_hw_params_test_rate(handle, hw_params.0, rate, 0) == 0 {
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rates.push((rate, rate));
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}
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}
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if rates.len() == 0 {
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vec![(min_rate, max_rate)]
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} else {
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rates
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}
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};
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let mut min_channels = 0;
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_channels_min(
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hw_params.0,
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&mut min_channels,
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)) {
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let description = format!("unable to get minimum supported channel count: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let mut max_channels = 0;
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_channels_max(
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hw_params.0,
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&mut max_channels,
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)) {
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let description = format!("unable to get maximum supported channel count: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let max_channels = cmp::min(max_channels, 32); // TODO: limiting to 32 channels or too much stuff is returned
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let supported_channels = (min_channels..max_channels + 1)
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.filter_map(|num| {
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if alsa::snd_pcm_hw_params_test_channels(handle, hw_params.0, num) == 0 {
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Some(num as ChannelCount)
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} else {
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None
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}
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})
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.collect::<Vec<_>>();
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let mut output = Vec::with_capacity(
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supported_formats.len() * supported_channels.len() * sample_rates.len(),
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);
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for &sample_format in supported_formats.iter() {
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for channels in supported_channels.iter() {
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for &(min_rate, max_rate) in sample_rates.iter() {
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output.push(SupportedStreamConfigRange {
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channels: channels.clone(),
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min_sample_rate: SampleRate(min_rate as u32),
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max_sample_rate: SampleRate(max_rate as u32),
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sample_format: sample_format,
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});
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}
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}
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}
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// TODO: RAII
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alsa::snd_pcm_close(handle);
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Ok(output.into_iter())
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}
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fn supported_input_configs(
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&self,
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) -> Result<SupportedInputConfigs, SupportedStreamConfigsError> {
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unsafe { self.supported_configs(alsa::SND_PCM_STREAM_CAPTURE) }
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}
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fn supported_output_configs(
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&self,
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) -> Result<SupportedOutputConfigs, SupportedStreamConfigsError> {
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unsafe { self.supported_configs(alsa::SND_PCM_STREAM_PLAYBACK) }
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}
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// ALSA does not offer default stream formats, so instead we compare all supported formats by
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// the `SupportedStreamConfigRange::cmp_default_heuristics` order and select the greatest.
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fn default_config(
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&self,
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stream_t: alsa::snd_pcm_stream_t,
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) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
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let mut formats: Vec<_> = unsafe {
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match self.supported_configs(stream_t) {
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Err(SupportedStreamConfigsError::DeviceNotAvailable) => {
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return Err(DefaultStreamConfigError::DeviceNotAvailable);
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}
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Err(SupportedStreamConfigsError::InvalidArgument) => {
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// this happens sometimes when querying for input and output capabilities but
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// the device supports only one
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return Err(DefaultStreamConfigError::StreamTypeNotSupported);
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}
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Err(SupportedStreamConfigsError::BackendSpecific { err }) => {
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return Err(err.into());
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}
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Ok(fmts) => fmts.collect(),
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}
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};
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formats.sort_by(|a, b| a.cmp_default_heuristics(b));
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match formats.into_iter().last() {
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Some(f) => {
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let min_r = f.min_sample_rate;
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let max_r = f.max_sample_rate;
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let mut format = f.with_max_sample_rate();
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const HZ_44100: SampleRate = SampleRate(44_100);
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if min_r <= HZ_44100 && HZ_44100 <= max_r {
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format.sample_rate = HZ_44100;
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}
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Ok(format)
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}
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None => Err(DefaultStreamConfigError::StreamTypeNotSupported),
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}
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}
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fn default_input_config(&self) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
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self.default_config(alsa::SND_PCM_STREAM_CAPTURE)
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}
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fn default_output_config(&self) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
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self.default_config(alsa::SND_PCM_STREAM_PLAYBACK)
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}
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}
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struct StreamInner {
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// The ALSA channel.
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channel: *mut alsa::snd_pcm_t,
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// When converting between file descriptors and `snd_pcm_t`, this is the number of
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// file descriptors that this `snd_pcm_t` uses.
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num_descriptors: usize,
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// Format of the samples.
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sample_format: SampleFormat,
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// Number of channels, ie. number of samples per frame.
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num_channels: u16,
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// Number of samples that can fit in the buffer.
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buffer_len: usize,
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// Minimum number of samples to put in the buffer.
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period_len: usize,
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// Whether or not the hardware supports pausing the stream.
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can_pause: bool,
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}
|
|
|
|
// Assume that the ALSA library is built with thread safe option.
|
|
unsafe impl Send for StreamInner {}
|
|
|
|
unsafe impl Sync for StreamInner {}
|
|
|
|
#[derive(Debug, Eq, PartialEq)]
|
|
enum StreamType {
|
|
Input,
|
|
Output,
|
|
}
|
|
|
|
pub struct Stream {
|
|
/// The high-priority audio processing thread calling callbacks.
|
|
/// Option used for moving out in destructor.
|
|
thread: Option<JoinHandle<()>>,
|
|
|
|
/// Handle to the underlying stream for playback controls.
|
|
inner: Arc<StreamInner>,
|
|
|
|
/// Used to signal to stop processing.
|
|
trigger: TriggerSender,
|
|
}
|
|
|
|
#[derive(Default)]
|
|
struct StreamWorkerContext {
|
|
descriptors: Vec<libc::pollfd>,
|
|
buffer: Vec<u8>,
|
|
}
|
|
|
|
fn input_stream_worker(
|
|
rx: TriggerReceiver,
|
|
stream: &StreamInner,
|
|
data_callback: &mut (dyn FnMut(&Data) + Send + 'static),
|
|
error_callback: &mut (dyn FnMut(StreamError) + Send + 'static),
|
|
) {
|
|
let mut ctxt = StreamWorkerContext::default();
|
|
loop {
|
|
match poll_descriptors_and_prepare_buffer(&rx, stream, &mut ctxt, error_callback) {
|
|
PollDescriptorsFlow::Continue => continue,
|
|
PollDescriptorsFlow::Return => return,
|
|
PollDescriptorsFlow::Ready {
|
|
available_frames,
|
|
stream_type,
|
|
} => {
|
|
assert_eq!(
|
|
stream_type,
|
|
StreamType::Input,
|
|
"expected input stream, but polling descriptors indicated output",
|
|
);
|
|
process_input(
|
|
stream,
|
|
&mut ctxt.buffer,
|
|
available_frames,
|
|
data_callback,
|
|
error_callback,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn output_stream_worker(
|
|
rx: TriggerReceiver,
|
|
stream: &StreamInner,
|
|
data_callback: &mut (dyn FnMut(&mut Data) + Send + 'static),
|
|
error_callback: &mut (dyn FnMut(StreamError) + Send + 'static),
|
|
) {
|
|
let mut ctxt = StreamWorkerContext::default();
|
|
loop {
|
|
match poll_descriptors_and_prepare_buffer(&rx, stream, &mut ctxt, error_callback) {
|
|
PollDescriptorsFlow::Continue => continue,
|
|
PollDescriptorsFlow::Return => return,
|
|
PollDescriptorsFlow::Ready {
|
|
available_frames,
|
|
stream_type,
|
|
} => {
|
|
assert_eq!(
|
|
stream_type,
|
|
StreamType::Output,
|
|
"expected output stream, but polling descriptors indicated input",
|
|
);
|
|
process_output(
|
|
stream,
|
|
&mut ctxt.buffer,
|
|
available_frames,
|
|
data_callback,
|
|
error_callback,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
enum PollDescriptorsFlow {
|
|
Continue,
|
|
Return,
|
|
Ready {
|
|
stream_type: StreamType,
|
|
available_frames: usize,
|
|
},
|
|
}
|
|
|
|
// This block is shared between both input and output stream worker functions.
|
|
fn poll_descriptors_and_prepare_buffer(
|
|
rx: &TriggerReceiver,
|
|
stream: &StreamInner,
|
|
ctxt: &mut StreamWorkerContext,
|
|
error_callback: &mut (dyn FnMut(StreamError) + Send + 'static),
|
|
) -> PollDescriptorsFlow {
|
|
let StreamWorkerContext {
|
|
ref mut descriptors,
|
|
ref mut buffer,
|
|
} = *ctxt;
|
|
|
|
descriptors.clear();
|
|
|
|
// Add the self-pipe for signaling termination.
|
|
descriptors.push(libc::pollfd {
|
|
fd: rx.0,
|
|
events: libc::POLLIN,
|
|
revents: 0,
|
|
});
|
|
|
|
// Add ALSA polling fds.
|
|
descriptors.reserve(stream.num_descriptors);
|
|
let len = descriptors.len();
|
|
let filled = unsafe {
|
|
alsa::snd_pcm_poll_descriptors(
|
|
stream.channel,
|
|
descriptors[len..].as_mut_ptr(),
|
|
stream.num_descriptors as libc::c_uint,
|
|
)
|
|
};
|
|
debug_assert_eq!(filled, stream.num_descriptors as libc::c_int);
|
|
unsafe {
|
|
descriptors.set_len(len + stream.num_descriptors);
|
|
}
|
|
|
|
let res = unsafe {
|
|
// Don't timeout, wait forever.
|
|
libc::poll(
|
|
descriptors.as_mut_ptr(),
|
|
descriptors.len() as libc::nfds_t,
|
|
-1,
|
|
)
|
|
};
|
|
if res < 0 {
|
|
let description = format!("`libc::poll()` failed: {}", io::Error::last_os_error());
|
|
error_callback(BackendSpecificError { description }.into());
|
|
return PollDescriptorsFlow::Continue;
|
|
} else if res == 0 {
|
|
let description = String::from("`libc::poll()` spuriously returned");
|
|
error_callback(BackendSpecificError { description }.into());
|
|
return PollDescriptorsFlow::Continue;
|
|
}
|
|
|
|
if descriptors[0].revents != 0 {
|
|
// The stream has been requested to be destroyed.
|
|
rx.clear_pipe();
|
|
return PollDescriptorsFlow::Return;
|
|
}
|
|
|
|
let stream_type = match check_for_pollout_or_pollin(stream, descriptors[1..].as_mut_ptr()) {
|
|
Ok(Some(ty)) => ty,
|
|
Ok(None) => {
|
|
// Nothing to process, poll again
|
|
return PollDescriptorsFlow::Continue;
|
|
}
|
|
Err(err) => {
|
|
error_callback(err.into());
|
|
return PollDescriptorsFlow::Continue;
|
|
}
|
|
};
|
|
// Get the number of available samples for reading/writing.
|
|
let available_samples = match get_available_samples(stream) {
|
|
Ok(n) => n,
|
|
Err(err) => {
|
|
let description = format!("Failed to query the number of available samples: {}", err);
|
|
error_callback(BackendSpecificError { description }.into());
|
|
return PollDescriptorsFlow::Continue;
|
|
}
|
|
};
|
|
|
|
// Only go on if there is at least `stream.period_len` samples.
|
|
if available_samples < stream.period_len {
|
|
return PollDescriptorsFlow::Continue;
|
|
}
|
|
|
|
// Prepare the data buffer.
|
|
let buffer_size = stream.sample_format.sample_size() * available_samples;
|
|
buffer.resize(buffer_size, 0u8);
|
|
let available_frames = available_samples / stream.num_channels as usize;
|
|
|
|
PollDescriptorsFlow::Ready {
|
|
stream_type,
|
|
available_frames,
|
|
}
|
|
}
|
|
|
|
// Read input data from ALSA and deliver it to the user.
|
|
fn process_input(
|
|
stream: &StreamInner,
|
|
buffer: &mut [u8],
|
|
available_frames: usize,
|
|
data_callback: &mut (dyn FnMut(&Data) + Send + 'static),
|
|
error_callback: &mut dyn FnMut(StreamError),
|
|
) {
|
|
let result = unsafe {
|
|
alsa::snd_pcm_readi(
|
|
stream.channel,
|
|
buffer.as_mut_ptr() as *mut _,
|
|
available_frames as alsa::snd_pcm_uframes_t,
|
|
)
|
|
};
|
|
if let Err(err) = check_errors(result as _) {
|
|
let description = format!("`snd_pcm_readi` failed: {}", err);
|
|
error_callback(BackendSpecificError { description }.into());
|
|
return;
|
|
}
|
|
let sample_format = stream.sample_format;
|
|
let data = buffer.as_mut_ptr() as *mut ();
|
|
let len = buffer.len() / sample_format.sample_size();
|
|
let data = unsafe { Data::from_parts(data, len, sample_format) };
|
|
data_callback(&data);
|
|
}
|
|
|
|
// Request data from the user's function and write it via ALSA.
|
|
//
|
|
// Returns `true`
|
|
fn process_output(
|
|
stream: &StreamInner,
|
|
buffer: &mut [u8],
|
|
available_frames: usize,
|
|
data_callback: &mut (dyn FnMut(&mut Data) + Send + 'static),
|
|
error_callback: &mut dyn FnMut(StreamError),
|
|
) {
|
|
{
|
|
// We're now sure that we're ready to write data.
|
|
let sample_format = stream.sample_format;
|
|
let data = buffer.as_mut_ptr() as *mut ();
|
|
let len = buffer.len() / sample_format.sample_size();
|
|
let mut data = unsafe { Data::from_parts(data, len, sample_format) };
|
|
data_callback(&mut data);
|
|
}
|
|
loop {
|
|
let result = unsafe {
|
|
alsa::snd_pcm_writei(
|
|
stream.channel,
|
|
buffer.as_ptr() as *const _,
|
|
available_frames as alsa::snd_pcm_uframes_t,
|
|
)
|
|
};
|
|
if result == -libc::EPIPE as i64 {
|
|
// buffer underrun
|
|
// TODO: Notify the user of this.
|
|
unsafe { alsa::snd_pcm_recover(stream.channel, result as i32, 0) };
|
|
} else if let Err(err) = check_errors(result as _) {
|
|
let description = format!("`snd_pcm_writei` failed: {}", err);
|
|
error_callback(BackendSpecificError { description }.into());
|
|
continue;
|
|
} else if result as usize != available_frames {
|
|
let description = format!(
|
|
"unexpected number of frames written: expected {}, \
|
|
result {} (this should never happen)",
|
|
available_frames, result,
|
|
);
|
|
error_callback(BackendSpecificError { description }.into());
|
|
continue;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Stream {
|
|
fn new_input<D, E>(
|
|
inner: Arc<StreamInner>,
|
|
mut data_callback: D,
|
|
mut error_callback: E,
|
|
) -> Stream
|
|
where
|
|
D: FnMut(&Data) + Send + 'static,
|
|
E: FnMut(StreamError) + Send + 'static,
|
|
{
|
|
let (tx, rx) = trigger();
|
|
// Clone the handle for passing into worker thread.
|
|
let stream = inner.clone();
|
|
let thread = thread::spawn(move || {
|
|
input_stream_worker(rx, &*stream, &mut data_callback, &mut error_callback);
|
|
});
|
|
Stream {
|
|
thread: Some(thread),
|
|
inner,
|
|
trigger: tx,
|
|
}
|
|
}
|
|
|
|
fn new_output<D, E>(
|
|
inner: Arc<StreamInner>,
|
|
mut data_callback: D,
|
|
mut error_callback: E,
|
|
) -> Stream
|
|
where
|
|
D: FnMut(&mut Data) + Send + 'static,
|
|
E: FnMut(StreamError) + Send + 'static,
|
|
{
|
|
let (tx, rx) = trigger();
|
|
// Clone the handle for passing into worker thread.
|
|
let stream = inner.clone();
|
|
let thread = thread::spawn(move || {
|
|
output_stream_worker(rx, &*stream, &mut data_callback, &mut error_callback);
|
|
});
|
|
Stream {
|
|
thread: Some(thread),
|
|
inner,
|
|
trigger: tx,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Drop for Stream {
|
|
fn drop(&mut self) {
|
|
self.trigger.wakeup();
|
|
self.thread.take().unwrap().join().unwrap();
|
|
}
|
|
}
|
|
|
|
impl StreamTrait for Stream {
|
|
fn play(&self) -> Result<(), PlayStreamError> {
|
|
unsafe {
|
|
alsa::snd_pcm_pause(self.inner.channel, 0);
|
|
}
|
|
// TODO: error handling
|
|
Ok(())
|
|
}
|
|
fn pause(&self) -> Result<(), PauseStreamError> {
|
|
unsafe {
|
|
alsa::snd_pcm_pause(self.inner.channel, 1);
|
|
}
|
|
// TODO: error handling
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
// Check whether the event is `POLLOUT` or `POLLIN`.
|
|
//
|
|
// If so, return the stream type associated with the event.
|
|
//
|
|
// Otherwise, returns `Ok(None)`.
|
|
//
|
|
// Returns an `Err` if the `snd_pcm_poll_descriptors_revents` call fails.
|
|
fn check_for_pollout_or_pollin(
|
|
stream: &StreamInner,
|
|
stream_descriptor_ptr: *mut libc::pollfd,
|
|
) -> Result<Option<StreamType>, BackendSpecificError> {
|
|
let (revent, res) = unsafe {
|
|
let mut revent = 0;
|
|
let res = alsa::snd_pcm_poll_descriptors_revents(
|
|
stream.channel,
|
|
stream_descriptor_ptr,
|
|
stream.num_descriptors as libc::c_uint,
|
|
&mut revent,
|
|
);
|
|
(revent, res)
|
|
};
|
|
if let Err(desc) = check_errors(res) {
|
|
let description = format!("`snd_pcm_poll_descriptors_revents` failed: {}", desc);
|
|
let err = BackendSpecificError { description };
|
|
return Err(err);
|
|
}
|
|
|
|
if revent as i16 == libc::POLLOUT {
|
|
Ok(Some(StreamType::Output))
|
|
} else if revent as i16 == libc::POLLIN {
|
|
Ok(Some(StreamType::Input))
|
|
} else {
|
|
Ok(None)
|
|
}
|
|
}
|
|
|
|
// Determine the number of samples that are available to read/write.
|
|
fn get_available_samples(stream: &StreamInner) -> Result<usize, BackendSpecificError> {
|
|
let available = unsafe { alsa::snd_pcm_avail_update(stream.channel) };
|
|
if available == -32 {
|
|
// buffer underrun
|
|
// TODO: Notify the user some how.
|
|
Ok(stream.buffer_len)
|
|
} else if let Err(desc) = check_errors(available as libc::c_int) {
|
|
let description = format!("failed to get available samples: {}", desc);
|
|
let err = BackendSpecificError { description };
|
|
Err(err)
|
|
} else {
|
|
Ok((available * stream.num_channels as alsa::snd_pcm_sframes_t) as usize)
|
|
}
|
|
}
|
|
|
|
unsafe fn set_hw_params_from_format(
|
|
pcm_handle: *mut alsa::snd_pcm_t,
|
|
hw_params: &HwParams,
|
|
format: &SupportedStreamConfig,
|
|
) -> Result<(), String> {
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_any(pcm_handle, hw_params.0)) {
|
|
return Err(format!("errors on pcm handle: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_access(
|
|
pcm_handle,
|
|
hw_params.0,
|
|
alsa::SND_PCM_ACCESS_RW_INTERLEAVED,
|
|
)) {
|
|
return Err(format!("handle not acessible: {}", e));
|
|
}
|
|
|
|
let sample_format = if cfg!(target_endian = "big") {
|
|
match format.sample_format {
|
|
SampleFormat::I16 => alsa::SND_PCM_FORMAT_S16_BE,
|
|
SampleFormat::U16 => alsa::SND_PCM_FORMAT_U16_BE,
|
|
SampleFormat::F32 => alsa::SND_PCM_FORMAT_FLOAT_BE,
|
|
}
|
|
} else {
|
|
match format.sample_format {
|
|
SampleFormat::I16 => alsa::SND_PCM_FORMAT_S16_LE,
|
|
SampleFormat::U16 => alsa::SND_PCM_FORMAT_U16_LE,
|
|
SampleFormat::F32 => alsa::SND_PCM_FORMAT_FLOAT_LE,
|
|
}
|
|
};
|
|
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_format(
|
|
pcm_handle,
|
|
hw_params.0,
|
|
sample_format,
|
|
)) {
|
|
return Err(format!("format could not be set: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_rate(
|
|
pcm_handle,
|
|
hw_params.0,
|
|
format.sample_rate.0 as libc::c_uint,
|
|
0,
|
|
)) {
|
|
return Err(format!("sample rate could not be set: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_channels(
|
|
pcm_handle,
|
|
hw_params.0,
|
|
format.channels as libc::c_uint,
|
|
)) {
|
|
return Err(format!("channel count could not be set: {}", e));
|
|
}
|
|
|
|
// If this isn't set manually a overlarge buffer may be used causing audio delay
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_buffer_time_near(
|
|
pcm_handle,
|
|
hw_params.0,
|
|
&mut 100_000,
|
|
&mut 0,
|
|
)) {
|
|
return Err(format!("buffer time could not be set: {}", e));
|
|
}
|
|
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params(pcm_handle, hw_params.0)) {
|
|
return Err(format!("hardware params could not be set: {}", e));
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
unsafe fn set_sw_params_from_format(
|
|
pcm_handle: *mut alsa::snd_pcm_t,
|
|
format: &SupportedStreamConfig,
|
|
) -> Result<(usize, usize), String> {
|
|
let mut sw_params = ptr::null_mut(); // TODO: RAII
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_malloc(&mut sw_params)) {
|
|
return Err(format!("snd_pcm_sw_params_malloc failed: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_current(pcm_handle, sw_params)) {
|
|
return Err(format!("snd_pcm_sw_params_current failed: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_set_start_threshold(
|
|
pcm_handle, sw_params, 0,
|
|
)) {
|
|
return Err(format!(
|
|
"snd_pcm_sw_params_set_start_threshold failed: {}",
|
|
e
|
|
));
|
|
}
|
|
|
|
let (buffer_len, period_len) = {
|
|
let mut buffer = 0;
|
|
let mut period = 0;
|
|
if let Err(e) = check_errors(alsa::snd_pcm_get_params(
|
|
pcm_handle,
|
|
&mut buffer,
|
|
&mut period,
|
|
)) {
|
|
return Err(format!("failed to initialize buffer: {}", e));
|
|
}
|
|
if buffer == 0 {
|
|
return Err(format!("initialization resulted in a null buffer"));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_set_avail_min(
|
|
pcm_handle, sw_params, period,
|
|
)) {
|
|
return Err(format!("snd_pcm_sw_params_set_avail_min failed: {}", e));
|
|
}
|
|
let buffer = buffer as usize * format.channels as usize;
|
|
let period = period as usize * format.channels as usize;
|
|
(buffer, period)
|
|
};
|
|
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params(pcm_handle, sw_params)) {
|
|
return Err(format!("snd_pcm_sw_params failed: {}", e));
|
|
}
|
|
|
|
alsa::snd_pcm_sw_params_free(sw_params);
|
|
Ok((buffer_len, period_len))
|
|
}
|
|
|
|
/// Wrapper around `hw_params`.
|
|
struct HwParams(*mut alsa::snd_pcm_hw_params_t);
|
|
|
|
impl HwParams {
|
|
pub fn alloc() -> HwParams {
|
|
unsafe {
|
|
let mut hw_params = ptr::null_mut();
|
|
check_errors(alsa::snd_pcm_hw_params_malloc(&mut hw_params))
|
|
.expect("unable to get hardware parameters");
|
|
HwParams(hw_params)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Drop for HwParams {
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
alsa::snd_pcm_hw_params_free(self.0);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Drop for StreamInner {
|
|
#[inline]
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
alsa::snd_pcm_close(self.channel);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn check_errors(err: libc::c_int) -> Result<(), String> {
|
|
if err < 0 {
|
|
unsafe {
|
|
let s = ffi::CStr::from_ptr(alsa::snd_strerror(err))
|
|
.to_bytes()
|
|
.to_vec();
|
|
let s = String::from_utf8(s).expect("Streaming error occured");
|
|
return Err(s);
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|