cpal/src/wasapi/voice.rs

use super::com;
use super::ole32;
use super::winapi;
use super::Endpoint;
use super::check_result;

use std::cmp;
use std::slice;
use std::mem;
use std::ptr;
use std::marker::PhantomData;

use CreationError;
use ChannelPosition;
use Format;
use SampleFormat;

pub struct Voice {
    audio_client: *mut winapi::IAudioClient,
    render_client: *mut winapi::IAudioRenderClient,
    max_frames_in_buffer: winapi::UINT32,
    num_channels: winapi::WORD,
    bytes_per_frame: winapi::WORD,
    samples_per_second: winapi::DWORD,
    bits_per_sample: winapi::WORD,
    playing: bool,
}

unsafe impl Send for Voice {}
unsafe impl Sync for Voice {}

impl Voice {
    pub fn new(end_point: &Endpoint, format: &Format) -> Result<Voice, CreationError> {
        // FIXME: release everything
        unsafe {
            // making sure that COM is initialized
            // it's not actually sure that this is required, but when in doubt do it
            com::com_initialized();

            // obtaining a `IAudioClient`
            let audio_client = match end_point.build_audioclient() {
                Err(ref e) if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) =>
                    return Err(CreationError::DeviceNotAvailable),
                e => e.unwrap(),
            };

            // computing the format and initializing the device
            let format = {
                let format_attempt = winapi::WAVEFORMATEXTENSIBLE {
                    Format: winapi::WAVEFORMATEX {
                        wFormatTag: match format.data_type {
                            SampleFormat::I16 => winapi::WAVE_FORMAT_PCM,
                            SampleFormat::F32 => winapi::WAVE_FORMAT_EXTENSIBLE,
                            SampleFormat::U16 => return Err(CreationError::FormatNotSupported),
                        },
                        nChannels: format.channels.len() as winapi::WORD,
                        nSamplesPerSec: format.samples_rate.0 as winapi::DWORD,
                        nAvgBytesPerSec: format.channels.len() as winapi::DWORD *
                                         format.samples_rate.0 as winapi::DWORD *
                                         format.data_type.get_sample_size() as winapi::DWORD,
                        nBlockAlign: format.channels.len() as winapi::WORD *
                                     format.data_type.get_sample_size() as winapi::WORD,
                        wBitsPerSample: 8 * format.data_type.get_sample_size() as winapi::WORD,
                        cbSize: match format.data_type {
                            SampleFormat::I16 => 0,
                            SampleFormat::F32 => (mem::size_of::<winapi::WAVEFORMATEXTENSIBLE>() -
                                                  mem::size_of::<winapi::WAVEFORMATEX>()) as winapi::WORD,
                            SampleFormat::U16 => return Err(CreationError::FormatNotSupported),
                        },
                    },
                    Samples: 8 * format.data_type.get_sample_size() as winapi::WORD,
                    dwChannelMask: {
                        let mut mask = 0;
                        for &channel in format.channels.iter() {
                            let raw_value = match channel {
                                ChannelPosition::FrontLeft => winapi::SPEAKER_FRONT_LEFT,
                                ChannelPosition::FrontRight => winapi::SPEAKER_FRONT_RIGHT,
                                ChannelPosition::FrontCenter => winapi::SPEAKER_FRONT_CENTER,
                                ChannelPosition::LowFrequency => winapi::SPEAKER_LOW_FREQUENCY,
                                ChannelPosition::BackLeft => winapi::SPEAKER_BACK_LEFT,
                                ChannelPosition::BackRight => winapi::SPEAKER_BACK_RIGHT,
                                ChannelPosition::FrontLeftOfCenter => winapi::SPEAKER_FRONT_LEFT_OF_CENTER,
                                ChannelPosition::FrontRightOfCenter => winapi::SPEAKER_FRONT_RIGHT_OF_CENTER,
                                ChannelPosition::BackCenter => winapi::SPEAKER_BACK_CENTER,
                                ChannelPosition::SideLeft => winapi::SPEAKER_SIDE_LEFT,
                                ChannelPosition::SideRight => winapi::SPEAKER_SIDE_RIGHT,
                                ChannelPosition::TopCenter => winapi::SPEAKER_TOP_CENTER,
                                ChannelPosition::TopFrontLeft => winapi::SPEAKER_TOP_FRONT_LEFT,
                                ChannelPosition::TopFrontCenter => winapi::SPEAKER_TOP_FRONT_CENTER,
                                ChannelPosition::TopFrontRight => winapi::SPEAKER_TOP_FRONT_RIGHT,
                                ChannelPosition::TopBackLeft => winapi::SPEAKER_TOP_BACK_LEFT,
                                ChannelPosition::TopBackCenter => winapi::SPEAKER_TOP_BACK_CENTER,
                                ChannelPosition::TopBackRight => winapi::SPEAKER_TOP_BACK_RIGHT,
                            };

                            // channels must be in the right order
                            if raw_value <= mask {
                                return Err(CreationError::FormatNotSupported);
                            }

                            mask = mask | raw_value;
                        }

                        mask
                    },
                    SubFormat: match format.data_type {
                        SampleFormat::I16 => winapi::KSDATAFORMAT_SUBTYPE_PCM,
                        SampleFormat::F32 => winapi::KSDATAFORMAT_SUBTYPE_IEEE_FLOAT,
                        SampleFormat::U16 => return Err(CreationError::FormatNotSupported),
                    },
                };

                let mut format_ptr: *mut winapi::WAVEFORMATEX = mem::uninitialized();
                let hresult = (*audio_client).IsFormatSupported(winapi::AUDCLNT_SHAREMODE::AUDCLNT_SHAREMODE_SHARED,
                                                                &format_attempt.Format, &mut format_ptr);

                if !format_ptr.is_null() {
                    ole32::CoTaskMemFree(format_ptr as *mut _);
                }

                if hresult == winapi::S_FALSE {
                    return Err(CreationError::FormatNotSupported);
                }

                match check_result(hresult) {
                    Err(ref e) if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) =>
                    {
                        (*audio_client).Release();
                        return Err(CreationError::DeviceNotAvailable);
                    },
                    Err(e) => {
                        (*audio_client).Release();
                        panic!("{:?}", e);
                    },
                    Ok(()) => (),
                };

                let hresult = (*audio_client).Initialize(winapi::AUDCLNT_SHAREMODE::AUDCLNT_SHAREMODE_SHARED,
                                                         0, 10000000, 0, &format_attempt.Format, ptr::null());

                match check_result(hresult) {
                    Err(ref e) if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) =>
                    {
                        (*audio_client).Release();
                        return Err(CreationError::DeviceNotAvailable);
                    },
                    Err(e) => {
                        (*audio_client).Release();
                        panic!("{:?}", e);
                    },
                    Ok(()) => (),
                };

                format_attempt.Format
            };

            // 
            let max_frames_in_buffer = {
                let mut max_frames_in_buffer = mem::uninitialized();
                let hresult = (*audio_client).GetBufferSize(&mut max_frames_in_buffer);

                match check_result(hresult) {
                    Err(ref e) if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) =>
                    {
                        (*audio_client).Release();
                        return Err(CreationError::DeviceNotAvailable);
                    },
                    Err(e) => {
                        (*audio_client).Release();
                        panic!("{:?}", e);
                    },
                    Ok(()) => (),
                };

                max_frames_in_buffer
            };

            // 
            let render_client = {
                let mut render_client: *mut winapi::IAudioRenderClient = mem::uninitialized();
                let hresult = (*audio_client).GetService(&winapi::IID_IAudioRenderClient,
                                                         &mut render_client as *mut *mut winapi::IAudioRenderClient
                                                                            as *mut _);

                match check_result(hresult) {
                    Err(ref e) if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) =>
                    {
                        (*audio_client).Release();
                        return Err(CreationError::DeviceNotAvailable);
                    },
                    Err(e) => {
                        (*audio_client).Release();
                        panic!("{:?}", e);
                    },
                    Ok(()) => (),
                };

                &mut *render_client
            };

            Ok(Voice {
                audio_client: audio_client,
                render_client: render_client,
                max_frames_in_buffer: max_frames_in_buffer,
                num_channels: format.nChannels,
                bytes_per_frame: format.nBlockAlign,
                samples_per_second: format.nSamplesPerSec,
                bits_per_sample: format.wBitsPerSample,
                playing: false,
            })
        }
    }

    #[inline]
    pub fn get_channels(&self) -> ::ChannelsCount {
        self.num_channels as ::ChannelsCount
    }

    #[inline]
    pub fn get_samples_rate(&self) -> ::SamplesRate {
        ::SamplesRate(self.samples_per_second as u32)
    }

    #[inline]
    pub fn get_samples_format(&self) -> ::SampleFormat {
        match self.bits_per_sample {
            16 => ::SampleFormat::I16,
            32 => ::SampleFormat::F32,
            _ => panic!("{}-bit format not yet supported", self.bits_per_sample),
        }
    }

    pub fn append_data<'a, T>(&'a mut self, max_elements: usize) -> Buffer<'a, T> {
        unsafe {
            // 
            let frames_available = {
                let mut padding = mem::uninitialized();
                let hresult = (*self.audio_client).GetCurrentPadding(&mut padding);
                check_result(hresult).unwrap();
                self.max_frames_in_buffer - padding
            };

            let frames_available = cmp::min(frames_available,
                                            max_elements as u32 * mem::size_of::<T>() as u32 /
                                            self.bytes_per_frame as u32);

            if frames_available == 0 {
                return Buffer::Empty;
            }

            // loading buffer
            let (buffer_data, buffer_len) = {
                let mut buffer: *mut winapi::BYTE = mem::uninitialized();
                let hresult = (*self.render_client).GetBuffer(frames_available,
                                &mut buffer as *mut *mut _);
                check_result(hresult).unwrap();
                assert!(!buffer.is_null());

                (buffer as *mut T,
                 frames_available as usize * self.bytes_per_frame as usize
                      / mem::size_of::<T>())
            };

            Buffer::Buffer {
                render_client: self.render_client,
                buffer_data: buffer_data,
                buffer_len: buffer_len,
                frames: frames_available,
                marker: PhantomData,
            }
        }
    }

    #[inline]
    pub fn play(&mut self) {
        if !self.playing {
            unsafe {
                let hresult = (*self.audio_client).Start();
                check_result(hresult).unwrap();
            }
        }

        self.playing = true;
    }

    #[inline]
    pub fn pause(&mut self) {
        if self.playing {
            unsafe {
                let hresult = (*self.audio_client).Stop();
                check_result(hresult).unwrap();
            }
        }

        self.playing = false;
    }

    pub fn underflowed(&self) -> bool {
        unsafe {
            let mut padding = mem::uninitialized();
            let hresult = (*self.audio_client).GetCurrentPadding(&mut padding);
            check_result(hresult).unwrap();
            
            padding == 0
        }
    }
}

impl Drop for Voice {
    #[inline]
    fn drop(&mut self) {
        unsafe {
            (*self.render_client).Release();
            (*self.audio_client).Release();
        }
    }
}

pub enum Buffer<'a, T: 'a> {
    Empty,
    Buffer {
        render_client: *mut winapi::IAudioRenderClient,
        buffer_data: *mut T,
        buffer_len: usize,
        frames: winapi::UINT32,
        marker: PhantomData<&'a mut T>,
    },
}

impl<'a, T> Buffer<'a, T> {
    #[inline]
    pub fn get_buffer<'b>(&'b mut self) -> &'b mut [T] {
        match self {
            &mut Buffer::Empty => &mut [],
            &mut Buffer::Buffer { buffer_data, buffer_len, .. } => unsafe {
                slice::from_raw_parts_mut(buffer_data, buffer_len)
            },
        }
    }

    #[inline]
    pub fn len(&self) -> usize {
        match self {
            &Buffer::Empty => 0,
            &Buffer::Buffer { buffer_len, .. } => buffer_len,
        }
    }

    #[inline]
    pub fn finish(self) {
        if let Buffer::Buffer { render_client, frames, .. } = self {
            unsafe {
                let hresult = (*render_client).ReleaseBuffer(frames as u32, 0);
                check_result(hresult).unwrap();
            }
        }
    }
}