cpal/asio-sys/src/bindings/mod.rs

1009 lines
34 KiB
Rust

pub mod asio_import;
#[macro_use]
pub mod errors;
use self::errors::{AsioError, AsioErrorWrapper, LoadDriverError};
use num_traits::FromPrimitive;
use std::ffi::CStr;
use std::ffi::CString;
use std::os::raw::{c_char, c_double, c_long, c_void};
use std::sync::{Arc, Mutex, MutexGuard, Weak};
// Bindings import
use self::asio_import as ai;
/// A handle to the ASIO API.
///
/// There should only be one instance of this type at any point in time.
#[derive(Debug)]
pub struct Asio {
// Keeps track of whether or not a driver is already loaded.
//
// This is necessary as ASIO only supports one `Driver` at a time.
loaded_driver: Mutex<Weak<DriverInner>>,
}
/// A handle to a single ASIO driver.
///
/// Creating an instance of this type loads and initialises the driver.
///
/// Dropping all `Driver` instances will automatically dispose of any resources and de-initialise
/// the driver.
#[derive(Clone, Debug)]
pub struct Driver {
inner: Arc<DriverInner>,
}
// Contains the state associated with a `Driver`.
//
// This state may be shared between multiple `Driver` handles representing the same underlying
// driver. Only when the last `Driver` is dropped will the `Drop` implementation for this type run
// and the necessary driver resources will be de-allocated and unloaded.
//
// The same could be achieved by returning an `Arc<Driver>` from the `Host::load_driver` API,
// however the `DriverInner` abstraction is required in order to allow for the `Driver::destroy`
// method to exist safely. By wrapping the `Arc<DriverInner>` in the `Driver` type, we can make
// sure the user doesn't `try_unwrap` the `Arc` and invalidate the `Asio` instance's weak pointer.
// This would allow for instantiation of a separate driver before the existing one is destroyed,
// which is disallowed by ASIO.
#[derive(Debug)]
struct DriverInner {
state: Mutex<DriverState>,
// The unique name associated with this driver.
name: String,
// Track whether or not the driver has been destroyed.
//
// This allows for the user to manually destroy the driver and handle any errors if they wish.
//
// In the case that the driver has been manually destroyed this flag will be set to `true`
// indicating to the `drop` implementation that there is nothing to be done.
destroyed: bool,
}
/// All possible states of an ASIO `Driver` instance.
///
/// Mapped to the finite state machine in the ASIO SDK docs.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub enum DriverState {
Initialized,
Prepared,
Running,
}
/// Amount of input and output
/// channels available.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub struct Channels {
pub ins: c_long,
pub outs: c_long,
}
/// Sample rate of the ASIO driver.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub struct SampleRate {
pub rate: u32,
}
/// Information provided to the BufferCallback.
#[derive(Debug)]
pub struct CallbackInfo {
pub buffer_index: i32,
pub system_time: ai::ASIOTimeStamp,
}
/// Holds the pointer to the callbacks that come from cpal
struct BufferCallback(Box<dyn FnMut(&CallbackInfo) + Send>);
/// Input and Output streams.
///
/// There is only ever max one input and one output.
///
/// Only one is required.
pub struct AsioStreams {
pub input: Option<AsioStream>,
pub output: Option<AsioStream>,
}
/// A stream to ASIO.
///
/// Contains the buffers.
pub struct AsioStream {
/// A Double buffer per channel
pub buffer_infos: Vec<AsioBufferInfo>,
/// Size of each buffer
pub buffer_size: i32,
}
/// All the possible types from ASIO.
/// This is a direct copy of the ASIOSampleType
/// inside ASIO SDK.
#[derive(Debug, FromPrimitive)]
#[repr(C)]
pub enum AsioSampleType {
ASIOSTInt16MSB = 0,
ASIOSTInt24MSB = 1, // used for 20 bits as well
ASIOSTInt32MSB = 2,
ASIOSTFloat32MSB = 3, // IEEE 754 32 bit float
ASIOSTFloat64MSB = 4, // IEEE 754 64 bit double float
// these are used for 32 bit data buffer, with different alignment of the data inside
// 32 bit PCI bus systems can be more easily used with these
ASIOSTInt32MSB16 = 8, // 32 bit data with 16 bit alignment
ASIOSTInt32MSB18 = 9, // 32 bit data with 18 bit alignment
ASIOSTInt32MSB20 = 10, // 32 bit data with 20 bit alignment
ASIOSTInt32MSB24 = 11, // 32 bit data with 24 bit alignment
ASIOSTInt16LSB = 16,
ASIOSTInt24LSB = 17, // used for 20 bits as well
ASIOSTInt32LSB = 18,
ASIOSTFloat32LSB = 19, // IEEE 754 32 bit float, as found on Intel x86 architecture
ASIOSTFloat64LSB = 20, // IEEE 754 64 bit double float, as found on Intel x86 architecture
// these are used for 32 bit data buffer, with different alignment of the data inside
// 32 bit PCI bus systems can more easily used with these
ASIOSTInt32LSB16 = 24, // 32 bit data with 18 bit alignment
ASIOSTInt32LSB18 = 25, // 32 bit data with 18 bit alignment
ASIOSTInt32LSB20 = 26, // 32 bit data with 20 bit alignment
ASIOSTInt32LSB24 = 27, // 32 bit data with 24 bit alignment
// ASIO DSD format.
ASIOSTDSDInt8LSB1 = 32, // DSD 1 bit data, 8 samples per byte. First sample in Least significant bit.
ASIOSTDSDInt8MSB1 = 33, // DSD 1 bit data, 8 samples per byte. First sample in Most significant bit.
ASIOSTDSDInt8NER8 = 40, // DSD 8 bit data, 1 sample per byte. No Endianness required.
ASIOSTLastEntry,
}
/// Gives information about buffers
/// Receives pointers to buffers
#[derive(Debug, Copy, Clone)]
#[repr(C)]
pub struct AsioBufferInfo {
/// 0 for output 1 for input
pub is_input: c_long,
/// Which channel. Starts at 0
pub channel_num: c_long,
/// Pointer to each half of the double buffer.
pub buffers: [*mut c_void; 2],
}
/// Callbacks that ASIO calls
#[repr(C)]
struct AsioCallbacks {
buffer_switch: extern "C" fn(double_buffer_index: c_long, direct_process: c_long) -> (),
sample_rate_did_change: extern "C" fn(s_rate: c_double) -> (),
asio_message: extern "C" fn(
selector: c_long,
value: c_long,
message: *mut (),
opt: *mut c_double,
) -> c_long,
buffer_switch_time_info: extern "C" fn(
params: *mut ai::ASIOTime,
double_buffer_index: c_long,
direct_process: c_long,
) -> *mut ai::ASIOTime,
}
/// A rust-usable version of the `ASIOTime` type that does not contain a binary blob for fields.
#[repr(C)]
pub struct AsioTime {
/// Must be `0`.
pub reserved: [c_long; 4],
/// Required.
pub time_info: AsioTimeInfo,
/// Optional, evaluated if (time_code.flags & ktcValid).
pub time_code: AsioTimeCode,
}
/// A rust-compatible version of the `ASIOTimeInfo` type that does not contain a binary blob for
/// fields.
#[repr(C)]
pub struct AsioTimeInfo {
/// Absolute speed (1. = nominal).
pub speed: c_double,
/// System time related to sample_position, in nanoseconds.
///
/// On Windows, must be derived from timeGetTime().
pub system_time: ai::ASIOTimeStamp,
/// Sample position since `ASIOStart()`.
pub sample_position: ai::ASIOSamples,
/// Current rate, unsigned.
pub sample_rate: AsioSampleRate,
/// See `AsioTimeInfoFlags`.
pub flags: c_long,
/// Must be `0`.
pub reserved: [c_char; 12],
}
/// A rust-compatible version of the `ASIOTimeCode` type that does not use a binary blob for its
/// fields.
#[repr(C)]
pub struct AsioTimeCode {
/// Speed relation (fraction of nominal speed) optional.
///
/// Set to 0. or 1. if not supported.
pub speed: c_double,
/// Time in samples unsigned.
pub time_code_samples: ai::ASIOSamples,
/// See `ASIOTimeCodeFlags`.
pub flags: c_long,
/// Set to `0`.
pub future: [c_char; 64],
}
/// A rust-compatible version of the `ASIOSampleRate` type that does not use a binary blob for its
/// fields.
pub type AsioSampleRate = f64;
// A helper type to simplify retrieval of available buffer sizes.
#[derive(Default)]
struct BufferSizes {
min: c_long,
max: c_long,
pref: c_long,
grans: c_long,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct CallbackId(usize);
lazy_static! {
/// A global way to access all the callbacks.
///
/// This is required because of how ASIO calls the `buffer_switch` function with no data
/// parameters.
///
/// Options are used so that when a callback is removed we don't change the Vec indices.
///
/// The indices are how we match a callback with a stream.
static ref BUFFER_CALLBACK: Mutex<Vec<(CallbackId, BufferCallback)>> = Mutex::new(Vec::new());
}
impl Asio {
/// Initialise the ASIO API.
pub fn new() -> Self {
let loaded_driver = Mutex::new(Weak::new());
Asio { loaded_driver }
}
/// Returns the name for each available driver.
///
/// This is used at the start to allow the user to choose which driver they want.
pub fn driver_names(&self) -> Vec<String> {
// The most drivers we can take
const MAX_DRIVERS: usize = 100;
// Max length for divers name
const MAX_DRIVER_NAME_LEN: usize = 32;
// 2D array of driver names set to 0.
let mut driver_names: [[c_char; MAX_DRIVER_NAME_LEN]; MAX_DRIVERS] =
[[0; MAX_DRIVER_NAME_LEN]; MAX_DRIVERS];
// Pointer to each driver name.
let mut driver_name_ptrs: [*mut i8; MAX_DRIVERS] = [0 as *mut i8; MAX_DRIVERS];
for (ptr, name) in driver_name_ptrs.iter_mut().zip(&mut driver_names[..]) {
*ptr = (*name).as_mut_ptr();
}
unsafe {
let num_drivers =
ai::get_driver_names(driver_name_ptrs.as_mut_ptr(), MAX_DRIVERS as i32);
(0..num_drivers)
.map(|i| driver_name_to_utf8(&driver_names[i as usize]).to_string())
.collect()
}
}
/// If a driver has already been loaded, this will return that driver.
///
/// Returns `None` if no driver is currently loaded.
///
/// This can be useful to check before calling `load_driver` as ASIO only supports loading a
/// single driver at a time.
pub fn loaded_driver(&self) -> Option<Driver> {
self.loaded_driver
.lock()
.expect("failed to acquire loaded driver lock")
.upgrade()
.map(|inner| Driver { inner })
}
/// Load a driver from the given name.
///
/// Driver names compatible with this method can be produced via the `asio.driver_names()`
/// method.
///
/// NOTE: Despite many requests from users, ASIO only supports loading a single driver at a
/// time. Calling this method while a previously loaded `Driver` instance exists will result in
/// an error. That said, if this method is called with the name of a driver that has already
/// been loaded, that driver will be returned successfully.
pub fn load_driver(&self, driver_name: &str) -> Result<Driver, LoadDriverError> {
// Check whether or not a driver is already loaded.
if let Some(driver) = self.loaded_driver() {
if driver.name() == driver_name {
return Ok(driver);
} else {
return Err(LoadDriverError::DriverAlreadyExists);
}
}
// Make owned CString to send to load driver
let driver_name_cstring =
CString::new(driver_name).expect("failed to create `CString` from driver name");
let mut driver_info = std::mem::MaybeUninit::<ai::ASIODriverInfo>::uninit();
unsafe {
// TODO: Check that a driver of the same name does not already exist?
match ai::load_asio_driver(driver_name_cstring.as_ptr() as *mut i8) {
false => Err(LoadDriverError::LoadDriverFailed),
true => {
// Initialize ASIO.
asio_result!(ai::ASIOInit(driver_info.as_mut_ptr()))?;
let _driver_info = driver_info.assume_init();
let state = Mutex::new(DriverState::Initialized);
let name = driver_name.to_string();
let destroyed = false;
let inner = Arc::new(DriverInner {
name,
state,
destroyed,
});
*self
.loaded_driver
.lock()
.expect("failed to acquire loaded driver lock") = Arc::downgrade(&inner);
let driver = Driver { inner };
Ok(driver)
}
}
}
}
}
impl BufferCallback {
/// Calls the inner callback.
fn run(&mut self, callback_info: &CallbackInfo) {
let cb = &mut self.0;
cb(callback_info);
}
}
impl Driver {
/// The name used to uniquely identify this driver.
pub fn name(&self) -> &str {
&self.inner.name
}
/// Returns the number of input and output channels available on the driver.
pub fn channels(&self) -> Result<Channels, AsioError> {
let mut ins: c_long = 0;
let mut outs: c_long = 0;
unsafe {
asio_result!(ai::ASIOGetChannels(&mut ins, &mut outs))?;
}
let channel = Channels { ins, outs };
Ok(channel)
}
/// Get the min and max supported buffersize of the driver.
pub fn buffersize_range(&self) -> Result<(c_long, c_long), AsioError> {
let buffer_sizes = asio_get_buffer_sizes()?;
let min = buffer_sizes.min;
let max = buffer_sizes.max;
Ok((min, max))
}
/// Get current sample rate of the driver.
pub fn sample_rate(&self) -> Result<c_double, AsioError> {
let mut rate: c_double = 0.0;
unsafe {
asio_result!(ai::get_sample_rate(&mut rate))?;
}
Ok(rate)
}
/// Can the driver accept the given sample rate.
pub fn can_sample_rate(&self, sample_rate: c_double) -> Result<bool, AsioError> {
unsafe {
match asio_result!(ai::can_sample_rate(sample_rate)) {
Ok(()) => Ok(true),
Err(AsioError::NoRate) => Ok(false),
Err(err) => Err(err),
}
}
}
/// Set the sample rate for the driver.
pub fn set_sample_rate(&self, sample_rate: c_double) -> Result<(), AsioError> {
unsafe {
asio_result!(ai::set_sample_rate(sample_rate))?;
}
Ok(())
}
/// Get the current data type of the driver's input stream.
///
/// This queries a single channel's type assuming all channels have the same sample type.
pub fn input_data_type(&self) -> Result<AsioSampleType, AsioError> {
stream_data_type(true)
}
/// Get the current data type of the driver's output stream.
///
/// This queries a single channel's type assuming all channels have the same sample type.
pub fn output_data_type(&self) -> Result<AsioSampleType, AsioError> {
stream_data_type(false)
}
/// Ask ASIO to allocate the buffers and give the callback pointers.
///
/// This will destroy any already allocated buffers.
///
/// If buffersize is None then the preferred buffer size from ASIO is used,
/// otherwise the desired buffersize is used if the requeted size is within
/// the range of accepted buffersizes for the device.
fn create_buffers(&self, buffer_infos: &mut [AsioBufferInfo], buffer_size: Option<i32>) -> Result<c_long, AsioError> {
let num_channels = buffer_infos.len();
// To pass as ai::ASIOCallbacks
let mut callbacks = create_asio_callbacks();
let mut state = self.inner.lock_state();
// Retrieve the available buffer sizes.
let buffer_sizes = asio_get_buffer_sizes()?;
if buffer_sizes.pref <= 0 {
panic!(
"`ASIOGetBufferSize` produced unusable preferred buffer size of {}",
buffer_sizes.pref,
);
}
let buffer_size = match buffer_size {
Some(v) => {
if v <= buffer_sizes.max {
v
} else {
return Err(AsioError::InvalidBufferSize)
}
},
None => buffer_sizes.pref,
};
// Ensure the driver is in the `Initialized` state.
if let DriverState::Running = *state {
state.stop()?;
}
if let DriverState::Prepared = *state {
state.dispose_buffers()?;
}
unsafe {
asio_result!(ai::ASIOCreateBuffers(
buffer_infos.as_mut_ptr() as *mut _,
num_channels as i32,
buffer_size,
&mut callbacks as *mut _ as *mut _,
))?;
}
*state = DriverState::Prepared;
Ok(buffer_size)
}
/// Creates the streams.
///
/// `buffer_size` sets the desired buffer_size. If None is passed in, then the
/// default buffersize for the device is used.
///
/// Both input and output streams need to be created together as a single slice of
/// `ASIOBufferInfo`.
fn create_streams(
&self,
mut input_buffer_infos: Vec<AsioBufferInfo>,
mut output_buffer_infos: Vec<AsioBufferInfo>,
buffer_size: Option<i32>,
) -> Result<AsioStreams, AsioError> {
let (input, output) = match (
input_buffer_infos.is_empty(),
output_buffer_infos.is_empty(),
) {
// Both stream exist.
(false, false) => {
// Create one continuous slice of buffers.
let split_point = input_buffer_infos.len();
let mut all_buffer_infos = input_buffer_infos;
all_buffer_infos.append(&mut output_buffer_infos);
// Create the buffers. On success, split the output and input again.
let buffer_size = self.create_buffers(&mut all_buffer_infos, buffer_size)?;
let output_buffer_infos = all_buffer_infos.split_off(split_point);
let input_buffer_infos = all_buffer_infos;
let input = Some(AsioStream {
buffer_infos: input_buffer_infos,
buffer_size,
});
let output = Some(AsioStream {
buffer_infos: output_buffer_infos,
buffer_size,
});
(input, output)
}
// Just input
(false, true) => {
let buffer_size = self.create_buffers(&mut input_buffer_infos, buffer_size)?;
let input = Some(AsioStream {
buffer_infos: input_buffer_infos,
buffer_size,
});
let output = None;
(input, output)
}
// Just output
(true, false) => {
let buffer_size = self.create_buffers(&mut output_buffer_infos, buffer_size)?;
let input = None;
let output = Some(AsioStream {
buffer_infos: output_buffer_infos,
buffer_size,
});
(input, output)
}
// Impossible
(true, true) => unreachable!("Trying to create streams without preparing"),
};
Ok(AsioStreams { input, output })
}
/// Prepare the input stream.
///
/// Because only the latest call to ASIOCreateBuffers is relevant this call will destroy all
/// past active buffers and recreate them.
///
/// For this reason we take the output stream if it exists.
///
/// `num_channels` is the desired number of input channels.
///
/// `buffer_size` sets the desired buffer_size. If None is passed in, then the
/// default buffersize for the device is used.
///
/// This returns a full AsioStreams with both input and output if output was active.
pub fn prepare_input_stream(
&self,
output: Option<AsioStream>,
num_channels: usize,
buffer_size: Option<i32>,
) -> Result<AsioStreams, AsioError> {
let input_buffer_infos = prepare_buffer_infos(true, num_channels);
let output_buffer_infos = output
.map(|output| output.buffer_infos)
.unwrap_or_else(Vec::new);
self.create_streams(input_buffer_infos, output_buffer_infos, buffer_size)
}
/// Prepare the output stream.
///
/// Because only the latest call to ASIOCreateBuffers is relevant this call will destroy all
/// past active buffers and recreate them.
///
/// For this reason we take the input stream if it exists.
///
/// `num_channels` is the desired number of output channels.
///
/// `buffer_size` sets the desired buffer_size. If None is passed in, then the
/// default buffersize for the device is used.
///
/// This returns a full AsioStreams with both input and output if input was active.
pub fn prepare_output_stream(
&self,
input: Option<AsioStream>,
num_channels: usize,
buffer_size: Option<i32>,
) -> Result<AsioStreams, AsioError> {
let input_buffer_infos = input
.map(|input| input.buffer_infos)
.unwrap_or_else(Vec::new);
let output_buffer_infos = prepare_buffer_infos(false, num_channels);
self.create_streams(input_buffer_infos, output_buffer_infos, buffer_size)
}
/// Releases buffers allocations.
///
/// This will `stop` the stream if the driver is `Running`.
///
/// No-op if no buffers are allocated.
pub fn dispose_buffers(&self) -> Result<(), AsioError> {
self.inner.dispose_buffers_inner()
}
/// Starts ASIO streams playing.
///
/// The driver must be in the `Prepared` state
///
/// If called successfully, the driver will be in the `Running` state.
///
/// No-op if already `Running`.
pub fn start(&self) -> Result<(), AsioError> {
let mut state = self.inner.lock_state();
if let DriverState::Running = *state {
return Ok(());
}
unsafe {
asio_result!(ai::ASIOStart())?;
}
*state = DriverState::Running;
Ok(())
}
/// Stops ASIO streams playing.
///
/// No-op if the state is not `Running`.
///
/// If the state was `Running` and the stream is stopped successfully, the driver will be in
/// the `Prepared` state.
pub fn stop(&self) -> Result<(), AsioError> {
self.inner.stop_inner()
}
/// Adds a callback to the list of active callbacks.
///
/// The given function receives the index of the buffer currently ready for processing.
///
/// Returns an ID uniquely associated with the given callback so that it may be removed later.
pub fn add_callback<F>(&self, callback: F) -> CallbackId
where
F: 'static + FnMut(&CallbackInfo) + Send,
{
let mut bc = BUFFER_CALLBACK.lock().unwrap();
let id = bc
.last()
.map(|&(id, _)| CallbackId(id.0.checked_add(1).expect("stream ID overflowed")))
.unwrap_or(CallbackId(0));
let cb = BufferCallback(Box::new(callback));
bc.push((id, cb));
id
}
/// Remove the callback with the given ID.
pub fn remove_callback(&self, rem_id: CallbackId) {
let mut bc = BUFFER_CALLBACK.lock().unwrap();
bc.retain(|&(id, _)| id != rem_id);
}
/// Consumes and destroys the `Driver`, stopping the streams if they are running and releasing
/// any associated resources.
///
/// Returns `Ok(true)` if the driver was successfully destroyed.
///
/// Returns `Ok(false)` if the driver was not destroyed because another handle to the driver
/// still exists.
///
/// Returns `Err` if some switching driver states failed or if ASIO returned an error on exit.
pub fn destroy(self) -> Result<bool, AsioError> {
let Driver { inner } = self;
match Arc::try_unwrap(inner) {
Err(_) => Ok(false),
Ok(mut inner) => {
inner.destroy_inner()?;
Ok(true)
}
}
}
}
impl DriverState {
fn stop(&mut self) -> Result<(), AsioError> {
if let DriverState::Running = *self {
unsafe {
asio_result!(ai::ASIOStop())?;
}
*self = DriverState::Prepared;
}
Ok(())
}
fn dispose_buffers(&mut self) -> Result<(), AsioError> {
if let DriverState::Initialized = *self {
return Ok(());
}
if let DriverState::Running = *self {
self.stop()?;
}
unsafe {
asio_result!(ai::ASIODisposeBuffers())?;
}
*self = DriverState::Initialized;
Ok(())
}
fn destroy(&mut self) -> Result<(), AsioError> {
if let DriverState::Running = *self {
self.stop()?;
}
if let DriverState::Prepared = *self {
self.dispose_buffers()?;
}
unsafe {
asio_result!(ai::ASIOExit())?;
ai::remove_current_driver();
}
Ok(())
}
}
impl DriverInner {
fn lock_state(&self) -> MutexGuard<DriverState> {
self.state.lock().expect("failed to lock `DriverState`")
}
fn stop_inner(&self) -> Result<(), AsioError> {
let mut state = self.lock_state();
state.stop()
}
fn dispose_buffers_inner(&self) -> Result<(), AsioError> {
let mut state = self.lock_state();
state.dispose_buffers()
}
fn destroy_inner(&mut self) -> Result<(), AsioError> {
{
let mut state = self.lock_state();
state.destroy()?;
// Clear any existing stream callbacks.
if let Ok(mut bcs) = BUFFER_CALLBACK.lock() {
bcs.clear();
}
}
// Signal that the driver has been destroyed.
self.destroyed = true;
Ok(())
}
}
impl Drop for DriverInner {
fn drop(&mut self) {
if !self.destroyed {
// We probably shouldn't `panic!` in the destructor? We also shouldn't ignore errors
// though either.
self.destroy_inner().ok();
}
}
}
unsafe impl Send for AsioStream {}
/// Used by the input and output stream creation process.
fn prepare_buffer_infos(is_input: bool, n_channels: usize) -> Vec<AsioBufferInfo> {
let is_input = if is_input { 1 } else { 0 };
(0..n_channels)
.map(|ch| {
let channel_num = ch as c_long;
// To be filled by ASIOCreateBuffers.
let buffers = [std::ptr::null_mut(); 2];
AsioBufferInfo {
is_input,
channel_num,
buffers,
}
})
.collect()
}
/// The set of callbacks passed to `ASIOCreateBuffers`.
fn create_asio_callbacks() -> AsioCallbacks {
AsioCallbacks {
buffer_switch: buffer_switch,
sample_rate_did_change: sample_rate_did_change,
asio_message: asio_message,
buffer_switch_time_info: buffer_switch_time_info,
}
}
/// Retrieve the minimum, maximum and preferred buffer sizes along with the available
/// buffer size granularity.
fn asio_get_buffer_sizes() -> Result<BufferSizes, AsioError> {
let mut b = BufferSizes::default();
unsafe {
let res = ai::ASIOGetBufferSize(&mut b.min, &mut b.max, &mut b.pref, &mut b.grans);
asio_result!(res)?;
}
Ok(b)
}
/// Retrieve the `ASIOChannelInfo` associated with the channel at the given index on either the
/// input or output stream (`true` for input).
fn asio_channel_info(channel: c_long, is_input: bool) -> Result<ai::ASIOChannelInfo, AsioError> {
let mut channel_info = ai::ASIOChannelInfo {
// Which channel we are querying
channel,
// Was it input or output
isInput: if is_input { 1 } else { 0 },
// Was it active
isActive: 0,
channelGroup: 0,
// The sample type
type_: 0,
name: [0 as c_char; 32],
};
unsafe {
asio_result!(ai::ASIOGetChannelInfo(&mut channel_info))?;
Ok(channel_info)
}
}
/// Retrieve the data type of either the input or output stream.
///
/// If `is_input` is true, this will be queried on the input stream.
fn stream_data_type(is_input: bool) -> Result<AsioSampleType, AsioError> {
let channel_info = asio_channel_info(0, is_input)?;
Ok(FromPrimitive::from_i32(channel_info.type_).expect("unkown `ASIOSampletype` value"))
}
/// ASIO uses null terminated c strings for driver names.
///
/// This converts to utf8.
fn driver_name_to_utf8(bytes: &[c_char]) -> std::borrow::Cow<str> {
unsafe { CStr::from_ptr(bytes.as_ptr()).to_string_lossy() }
}
/// ASIO uses null terminated c strings for channel names.
///
/// This converts to utf8.
fn _channel_name_to_utf8(bytes: &[c_char]) -> std::borrow::Cow<str> {
unsafe { CStr::from_ptr(bytes.as_ptr()).to_string_lossy() }
}
/// Indicates the stream sample rate has changed.
///
/// TODO: Provide some way of allowing CPAL to handle this.
extern "C" fn sample_rate_did_change(s_rate: c_double) -> () {
eprintln!("unhandled sample rate change to {}", s_rate);
}
/// Message callback for ASIO to notify of certain events.
extern "C" fn asio_message(
selector: c_long,
value: c_long,
_message: *mut (),
_opt: *mut c_double,
) -> c_long {
match selector {
ai::kAsioSelectorSupported => {
// Indicate what message selectors are supported.
match value {
| ai::kAsioResetRequest
| ai::kAsioEngineVersion
| ai::kAsioResyncRequest
| ai::kAsioLatenciesChanged
// Following added in ASIO 2.0.
| ai::kAsioSupportsTimeInfo
| ai::kAsioSupportsTimeCode
| ai::kAsioSupportsInputMonitor => 1,
_ => 0,
}
}
ai::kAsioResetRequest => {
// Defer the task and perform the reset of the driver during the next "safe" situation
// You cannot reset the driver right now, as this code is called from the driver. Reset
// the driver is done by completely destruct it. I.e. ASIOStop(), ASIODisposeBuffers(),
// Destruction. Afterwards you initialize the driver again.
// TODO: Handle this.
1
}
ai::kAsioResyncRequest => {
// This informs the application, that the driver encountered some non fatal data loss.
// It is used for synchronization purposes of different media. Added mainly to work
// around the Win16Mutex problems in Windows 95/98 with the Windows Multimedia system,
// which could loose data because the Mutex was hold too long by another thread.
// However a driver can issue it in other situations, too.
// TODO: Handle this.
1
}
ai::kAsioLatenciesChanged => {
// This will inform the host application that the drivers were latencies changed.
// Beware, it this does not mean that the buffer sizes have changed! You might need to
// update internal delay data.
// TODO: Handle this.
1
}
ai::kAsioEngineVersion => {
// Return the supported ASIO version of the host application If a host applications
// does not implement this selector, ASIO 1.0 is assumed by the driver
2
}
ai::kAsioSupportsTimeInfo => {
// Informs the driver whether the asioCallbacks.bufferSwitchTimeInfo() callback is
// supported. For compatibility with ASIO 1.0 drivers the host application should
// always support the "old" bufferSwitch method, too, which we do.
1
}
ai::kAsioSupportsTimeCode => {
// Informs the driver whether the application is interested in time code info. If an
// application does not need to know about time code, the driver has less work to do.
// TODO: Provide an option for this?
1
}
_ => 0, // Unknown/unhandled message type.
}
}
/// Similar to buffer switch but with time info.
///
/// If only `buffer_switch` is called by the driver instead, the `buffer_switch` callback will
/// create the necessary timing info and call this function.
///
/// TODO: Provide some access to `ai::ASIOTime` once CPAL gains support for time stamps.
extern "C" fn buffer_switch_time_info(
time: *mut ai::ASIOTime,
double_buffer_index: c_long,
_direct_process: c_long,
) -> *mut ai::ASIOTime {
// This lock is probably unavoidable, but locks in the audio stream are not great.
let mut bcs = BUFFER_CALLBACK.lock().unwrap();
let asio_time: &mut AsioTime = unsafe { &mut *(time as *mut AsioTime) };
let callback_info = CallbackInfo {
buffer_index: double_buffer_index,
system_time: asio_time.time_info.system_time,
};
for &mut (_, ref mut bc) in bcs.iter_mut() {
bc.run(&callback_info);
}
time
}
/// This is called by ASIO.
///
/// Here we run the callback for each stream.
///
/// `double_buffer_index` is either `0` or `1` indicating which buffer to fill.
extern "C" fn buffer_switch(double_buffer_index: c_long, direct_process: c_long) -> () {
// Emulate the time info provided by the `buffer_switch_time_info` callback.
// This is an attempt at matching the behaviour in `hostsample.cpp` from the SDK.
let mut time = unsafe {
let mut time: AsioTime = std::mem::zeroed();
let res = ai::ASIOGetSamplePosition(
&mut time.time_info.sample_position,
&mut time.time_info.system_time,
);
if let Ok(()) = asio_result!(res) {
time.time_info.flags = (ai::AsioTimeInfoFlags::kSystemTimeValid
| ai::AsioTimeInfoFlags::kSamplePositionValid)
.0;
}
time
};
// Actual processing happens within the `buffer_switch_time_info` callback.
let asio_time_ptr = &mut time as *mut AsioTime as *mut ai::ASIOTime;
buffer_switch_time_info(asio_time_ptr, double_buffer_index, direct_process);
}
#[test]
fn check_type_sizes() {
assert_eq!(
std::mem::size_of::<AsioSampleRate>(),
std::mem::size_of::<ai::ASIOSampleRate>()
);
assert_eq!(
std::mem::size_of::<AsioTimeCode>(),
std::mem::size_of::<ai::ASIOTimeCode>()
);
assert_eq!(
std::mem::size_of::<AsioTimeInfo>(),
std::mem::size_of::<ai::AsioTimeInfo>(),
);
assert_eq!(
std::mem::size_of::<AsioTime>(),
std::mem::size_of::<ai::ASIOTime>()
);
}