cpal 0.17.3

Low-level cross-platform audio I/O library in pure Rust.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258

pub use crate::iter::{SupportedInputConfigs, SupportedOutputConfigs};

use super::sys;
use crate::BackendSpecificError;
use crate::ChannelCount;
use crate::DefaultStreamConfigError;
use crate::DeviceDescription;
use crate::DeviceDescriptionBuilder;
use crate::DeviceId;
use crate::DeviceIdError;
use crate::DeviceNameError;
use crate::DevicesError;
use crate::SampleFormat;
use crate::SupportedBufferSize;
use crate::SupportedStreamConfig;
use crate::SupportedStreamConfigRange;
use crate::SupportedStreamConfigsError;

use std::hash::{Hash, Hasher};
use std::sync::atomic::AtomicU32;
use std::sync::{Arc, Mutex};

/// A ASIO Device
#[derive(Clone)]
pub struct Device {
    /// The driver represented by this device.
    pub driver: Arc<sys::Driver>,

    // Input and/or Output stream.
    // A driver can only have one of each.
    // They need to be created at the same time.
    pub asio_streams: Arc<Mutex<sys::AsioStreams>>,
    pub current_callback_flag: Arc<AtomicU32>,
}

/// All available devices.
pub struct Devices {
    asio: Arc<sys::Asio>,
    drivers: std::vec::IntoIter<String>,
}

impl PartialEq for Device {
    fn eq(&self, other: &Self) -> bool {
        self.driver.name() == other.driver.name()
    }
}

impl Eq for Device {}

impl Hash for Device {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.driver.name().hash(state);
    }
}

impl Device {
    pub fn description(&self) -> Result<DeviceDescription, DeviceNameError> {
        let driver_name = self.driver.name().to_string();

        let direction = crate::device_description::direction_from_counts(
            self.driver.channels().ok().map(|c| c.ins as ChannelCount),
            self.driver.channels().ok().map(|c| c.outs as ChannelCount),
        );

        Ok(DeviceDescriptionBuilder::new(driver_name.clone())
            .driver(driver_name)
            .direction(direction)
            .build())
    }

    pub fn id(&self) -> Result<DeviceId, DeviceIdError> {
        Ok(DeviceId(
            crate::platform::HostId::Asio,
            self.driver.name().to_string(),
        ))
    }

    /// Gets the supported input configs.
    /// TODO currently only supports the default.
    /// Need to find all possible configs.
    pub fn supported_input_configs(
        &self,
    ) -> Result<SupportedInputConfigs, SupportedStreamConfigsError> {
        // Retrieve the default config for the total supported channels and supported sample
        // format.
        let f = match self.default_input_config() {
            Err(_) => return Err(SupportedStreamConfigsError::DeviceNotAvailable),
            Ok(f) => f,
        };

        // Collect a config for every combination of supported sample rate and number of channels.
        let mut supported_configs = vec![];
        for &rate in crate::COMMON_SAMPLE_RATES {
            if !self
                .driver
                .can_sample_rate(rate.into())
                .ok()
                .unwrap_or(false)
            {
                continue;
            }
            for channels in 1..f.channels + 1 {
                supported_configs.push(SupportedStreamConfigRange {
                    channels,
                    min_sample_rate: rate,
                    max_sample_rate: rate,
                    buffer_size: f.buffer_size,
                    sample_format: f.sample_format,
                })
            }
        }
        Ok(supported_configs.into_iter())
    }

    /// Gets the supported output configs.
    /// TODO currently only supports the default.
    /// Need to find all possible configs.
    pub fn supported_output_configs(
        &self,
    ) -> Result<SupportedOutputConfigs, SupportedStreamConfigsError> {
        // Retrieve the default config for the total supported channels and supported sample
        // format.
        let f = match self.default_output_config() {
            Err(_) => return Err(SupportedStreamConfigsError::DeviceNotAvailable),
            Ok(f) => f,
        };

        // Collect a config for every combination of supported sample rate and number of channels.
        let mut supported_configs = vec![];
        for &rate in crate::COMMON_SAMPLE_RATES {
            if !self
                .driver
                .can_sample_rate(rate.into())
                .ok()
                .unwrap_or(false)
            {
                continue;
            }
            for channels in 1..f.channels + 1 {
                supported_configs.push(SupportedStreamConfigRange {
                    channels,
                    min_sample_rate: rate,
                    max_sample_rate: rate,
                    buffer_size: f.buffer_size,
                    sample_format: f.sample_format,
                })
            }
        }
        Ok(supported_configs.into_iter())
    }

    /// Returns the default input config
    pub fn default_input_config(&self) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
        let channels = self.driver.channels().map_err(default_config_err)?.ins as u16;
        let sample_rate = self.driver.sample_rate().map_err(default_config_err)? as u32;
        let (min, max) = self.driver.buffersize_range().map_err(default_config_err)?;
        let buffer_size = SupportedBufferSize::Range {
            min: min as u32,
            max: max as u32,
        };
        // Map th ASIO sample type to a CPAL sample type
        let data_type = self.driver.input_data_type().map_err(default_config_err)?;
        let sample_format = convert_data_type(&data_type)
            .ok_or(DefaultStreamConfigError::StreamTypeNotSupported)?;
        Ok(SupportedStreamConfig {
            channels,
            sample_rate,
            buffer_size,
            sample_format,
        })
    }

    /// Returns the default output config
    pub fn default_output_config(&self) -> Result<SupportedStreamConfig, DefaultStreamConfigError> {
        let channels = self.driver.channels().map_err(default_config_err)?.outs as u16;
        let sample_rate = self.driver.sample_rate().map_err(default_config_err)? as u32;
        let (min, max) = self.driver.buffersize_range().map_err(default_config_err)?;
        let buffer_size = SupportedBufferSize::Range {
            min: min as u32,
            max: max as u32,
        };
        let data_type = self.driver.output_data_type().map_err(default_config_err)?;
        let sample_format = convert_data_type(&data_type)
            .ok_or(DefaultStreamConfigError::StreamTypeNotSupported)?;
        Ok(SupportedStreamConfig {
            channels,
            sample_rate,
            buffer_size,
            sample_format,
        })
    }
}

impl Devices {
    pub fn new(asio: Arc<sys::Asio>) -> Result<Self, DevicesError> {
        let drivers = asio.driver_names().into_iter();
        Ok(Devices { asio, drivers })
    }
}

impl Iterator for Devices {
    type Item = Device;

    /// Load drivers and return device
    fn next(&mut self) -> Option<Device> {
        loop {
            match self.drivers.next() {
                Some(name) => match self.asio.load_driver(&name) {
                    Ok(driver) => {
                        let driver = Arc::new(driver);
                        let asio_streams = Arc::new(Mutex::new(sys::AsioStreams {
                            input: None,
                            output: None,
                        }));
                        return Some(Device {
                            driver,
                            asio_streams,
                            // Initialize with sentinel value so it never matches global flag state (0 or 1).
                            current_callback_flag: Arc::new(AtomicU32::new(u32::MAX)),
                        });
                    }
                    Err(_) => continue,
                },
                None => return None,
            }
        }
    }
}

pub(crate) fn convert_data_type(ty: &sys::AsioSampleType) -> Option<SampleFormat> {
    let fmt = match *ty {
        sys::AsioSampleType::ASIOSTInt16MSB => SampleFormat::I16,
        sys::AsioSampleType::ASIOSTInt16LSB => SampleFormat::I16,
        sys::AsioSampleType::ASIOSTInt24MSB => SampleFormat::I24,
        sys::AsioSampleType::ASIOSTInt24LSB => SampleFormat::I24,
        sys::AsioSampleType::ASIOSTInt32MSB => SampleFormat::I32,
        sys::AsioSampleType::ASIOSTInt32LSB => SampleFormat::I32,
        sys::AsioSampleType::ASIOSTFloat32MSB => SampleFormat::F32,
        sys::AsioSampleType::ASIOSTFloat32LSB => SampleFormat::F32,
        sys::AsioSampleType::ASIOSTFloat64MSB => SampleFormat::F64,
        sys::AsioSampleType::ASIOSTFloat64LSB => SampleFormat::F64,
        _ => return None,
    };
    Some(fmt)
}

fn default_config_err(e: sys::AsioError) -> DefaultStreamConfigError {
    match e {
        sys::AsioError::NoDrivers | sys::AsioError::HardwareMalfunction => {
            DefaultStreamConfigError::DeviceNotAvailable
        }
        sys::AsioError::NoRate => DefaultStreamConfigError::StreamTypeNotSupported,
        err => {
            let description = format!("{}", err);
            BackendSpecificError { description }.into()
        }
    }
}