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

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mod asio_import;
#[macro_use]
pub mod errors;
use num_traits::FromPrimitive;
use self::errors::{AsioError, AsioErrorWrapper, LoadDriverError};
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use std::ffi::CStr;
use std::ffi::CString;
use std::os::raw::{c_char, c_double, c_long, c_void};
use std::sync::atomic::{self, AtomicBool};
use std::sync::{Arc, Mutex};
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use std;
// 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.
driver_loaded: Arc<AtomicBool>,
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}
/// A handle to a single ASIO driver.
///
/// Creating an instance of this type loads and initialises the driver.
///
/// Dropping the instance will dispose of any resources and de-initialise the driver.
#[derive(Debug)]
pub struct Driver {
state: Mutex<DriverState>,
// A flag that is set to `false` when the `Driver` is dropped.
//
// This lets the `Asio` handle know that a new driver can be loaded.
loaded: Arc<AtomicBool>,
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}
/// 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,
}
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/// 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,
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}
/// Sample rate of the ASIO driver.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
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pub struct SampleRate {
pub rate: u32,
}
/// Holds the pointer to the callbacks that come from cpal
struct BufferCallback(Box<FnMut(i32) + Send>);
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/// Input and Output streams.
///
/// There is only ever max one input and one output.
///
/// Only one is required.
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pub struct AsioStreams {
pub input: Option<AsioStream>,
pub output: Option<AsioStream>,
}
/// A stream to ASIO.
///
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/// 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,
}
lazy_static! {
/// A global way to access all the callbacks.
/// This is required because of how ASIO
/// calls the buffer_switch function.
/// Options are used so that when a callback is
/// removed we don't change the Vec indicies.
/// The indicies are how we match a callback
/// with a stream.
static ref BUFFER_CALLBACK: Mutex<Vec<Option<BufferCallback>>> = Mutex::new(Vec::new());
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}
impl Asio {
/// Initialise the ASIO API.
pub fn new() -> Self {
let driver_loaded = Arc::new(AtomicBool::new(false));
Asio { driver_loaded }
}
/// 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 CHAR_LEN: usize = 32;
// 2D array of driver names set to 0
let mut driver_names: [[c_char; CHAR_LEN]; MAX_DRIVERS] = [[0; CHAR_LEN]; MAX_DRIVERS];
// Pointer to each driver name
let mut p_driver_name: [*mut i8; MAX_DRIVERS] = [0 as *mut i8; MAX_DRIVERS];
for i in 0 .. MAX_DRIVERS {
p_driver_name[i] = driver_names[i].as_mut_ptr();
}
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unsafe {
let num_drivers = ai::get_driver_names(p_driver_name.as_mut_ptr(), MAX_DRIVERS as i32);
(0 .. num_drivers)
.map(|i| {
let name = CStr::from_ptr(p_driver_name[i as usize]);
let my_driver_name = name.to_owned();
my_driver_name
.into_string()
.expect("Failed to convert driver name")
}).collect()
}
}
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/// Whether or not a driver has already been loaded by this process.
///
/// This can be useful to check before calling `load_driver` as ASIO only supports loading a
/// single driver at a time.
///
/// Uses the given atomic ordering to access the atomic boolean used to track driver loading.
pub fn is_driver_loaded(&self, ord: atomic::Ordering) -> bool {
self.driver_loaded.load(ord)
}
/// 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.
pub fn load_driver(&self, driver_name: &str) -> Result<Driver, LoadDriverError> {
if self.driver_loaded.load(atomic::Ordering::SeqCst) {
return Err(LoadDriverError::DriverAlreadyExists);
}
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// Make owned CString to send to load driver
let my_driver_name = CString::new(driver_name)
.expect("failed to create `CString` from driver name");
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let mut driver_info = ai::ASIODriverInfo {
_bindgen_opaque_blob: [0u32; 43],
};
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unsafe {
// TODO: Check that a driver of the same name does not already exist?
match ai::load_asio_driver(my_driver_name.as_ptr() as *mut i8) {
false => Err(LoadDriverError::LoadDriverFailed),
true => {
// Initialize ASIO.
asio_result!(ai::ASIOInit(&mut driver_info))?;
self.driver_loaded.store(true, atomic::Ordering::SeqCst);
let loaded = self.driver_loaded.clone();
let state = Mutex::new(DriverState::Initialized);
let driver = Driver { state, loaded };
Ok(driver)
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}
}
}
}
}
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impl BufferCallback {
/// Calls the inner callback
fn run(&mut self, index: i32) {
let cb = &mut self.0;
cb(index);
}
}
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impl Driver {
/// Returns the number of input and output channels available on the driver.
pub fn channels(&self) -> Result<Channels, AsioError> {
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let mut ins: c_long = 0;
let mut outs: c_long = 0;
unsafe {
asio_result!(ai::ASIOGetChannels(&mut ins, &mut outs))?;
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}
let channel = Channels { ins, outs };
Ok(channel)
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}
/// Get current sample rate of the driver.
pub fn sample_rate(&self) -> Result<c_double, AsioError> {
let mut rate: c_double = 0.0;
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unsafe {
asio_result!(ai::get_sample_rate(&mut rate))?;
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}
Ok(rate)
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}
/// 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),
}
}
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}
/// 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(())
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}
/// Get the current data type of the driver.
///
/// This queries a single channel's type assuming all channels have the same sample type.
///
/// TODO: Make this a seperate call for input and output as it is possible that input and
/// output have different sample types Initialize memory for calls.
pub fn data_type(&self) -> Result<AsioSampleType, AsioError> {
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let mut channel_info = ai::ASIOChannelInfo {
// Which channel we are querying
channel: 0,
// Was it input or output
isInput: 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(FromPrimitive::from_i32(channel_info.type_).expect("failed to cast sample type"))
}
}
/// Ask ASIO to allocate the buffers and give the callback pointers.
///
/// This will destroy any already allocated buffers.
///
/// The prefered buffer size from ASIO is used.
fn create_buffers(&self, buffer_infos: &mut [AsioBufferInfo]) -> Result<c_long, AsioError> {
let num_channels = buffer_infos.len();
let mut callbacks = 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,
};
// To pass as ai::ASIOCallbacks
let callbacks: *mut _ = &mut callbacks;
let mut min_b_size: c_long = 0;
let mut max_b_size: c_long = 0;
let mut pref_b_size: c_long = 0;
let mut grans: c_long = 0;
unsafe {
// Get the buffer sizes
// min possilbe size
// max possible size
// preferred size
// granularity
asio_result!(ai::ASIOGetBufferSize(
&mut min_b_size,
&mut max_b_size,
&mut pref_b_size,
&mut grans,
))?;
if pref_b_size <= 0 {
panic!(
"`ASIOGetBufferSize` produced unusable preferred buffer size of {}",
pref_b_size,
);
}
if let DriverState::Running = self.state() {
self.stop()?;
}
if let DriverState::Prepared = self.state() {
self.dispose_buffers()?;
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}
asio_result!(ai::ASIOCreateBuffers(
buffer_infos.as_mut_ptr() as *mut _,
num_channels as i32,
pref_b_size,
callbacks as *mut _,
))?;
}
self.set_state(DriverState::Prepared);
Ok(pref_b_size)
}
/// Creates the streams.
///
/// Both input and output streams need to be created together as a single slice of
/// `ASIOBufferInfo`.
fn create_streams(&self, streams: AsioStreams) -> Result<AsioStreams, AsioError> {
let AsioStreams { input, output } = streams;
match (input, output) {
// Both stream exist.
(Some(input), Some(mut output)) => {
let split_point = input.buffer_infos.len();
let mut bi = input.buffer_infos;
// Append the output to the input channels
bi.append(&mut output.buffer_infos);
// Create the buffers.
// if successful then split the output
// and input again
self.create_buffers(&mut bi).map(|buffer_size| {
let out_bi = bi.split_off(split_point);
let in_bi = bi;
let output = Some(AsioStream {
buffer_infos: out_bi,
buffer_size,
});
let input = Some(AsioStream {
buffer_infos: in_bi,
buffer_size,
});
AsioStreams { output, input }
})
},
// Just input
(Some(mut input), None) => {
self.create_buffers(&mut input.buffer_infos)
.map(|buffer_size| {
AsioStreams {
input: Some(AsioStream {
buffer_infos: input.buffer_infos,
buffer_size,
}),
output: None,
}
})
},
// Just output
(None, Some(mut output)) => {
self.create_buffers(&mut output.buffer_infos)
.map(|buffer_size| {
AsioStreams {
output: Some(AsioStream {
buffer_infos: output.buffer_infos,
buffer_size,
}),
input: None,
}
})
},
// Impossible
(None, None) => panic!("Trying to create streams without preparing"),
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}
}
/// 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.
///
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/// 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,
) -> Result<AsioStreams, AsioError> {
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let buffer_infos = (0 .. num_channels)
.map(|i| AsioBufferInfo {
// These are output channels
is_input: 1,
// Channel index
channel_num: i as c_long,
// Double buffer. We don't know the type
// at this point
buffers: [std::ptr::null_mut(); 2],
}).collect();
// Create the streams
let streams = AsioStreams {
input: Some(AsioStream {
buffer_infos,
buffer_size: 0,
}),
output,
};
self.create_streams(streams)
}
/// 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 number of output channels.
/// 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,
) -> Result<AsioStreams, AsioError> {
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// Initialize data for FFI
let buffer_infos = (0 .. num_channels)
.map(|i| AsioBufferInfo {
// These are outputs
is_input: 0,
// Channel index
channel_num: i as c_long,
// Pointer to each buffer. We don't know
// the type yet.
buffers: [std::ptr::null_mut(); 2],
}).collect();
// Create streams
let streams = AsioStreams {
output: Some(AsioStream {
buffer_infos,
buffer_size: 0,
}),
input,
};
self.create_streams(streams)
}
fn state(&self) -> DriverState {
*self.state.lock().expect("failed to lock `DriverState`")
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}
fn set_state(&self, state: DriverState) {
*self.state.lock().expect("failed to lock `DriverState`") = state;
}
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/// 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> {
if let DriverState::Initialized = self.state() {
return Ok(());
}
if let DriverState::Running = self.state() {
self.stop()?;
}
unsafe {
asio_result!(ai::ASIODisposeBuffers())?;
}
self.set_state(DriverState::Initialized);
Ok(())
}
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/// 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> {
if let DriverState::Running = self.state() {
return Ok(());
}
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unsafe {
asio_result!(ai::ASIOStart())?;
}
self.set_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> {
if let DriverState::Running = self.state() {
unsafe {
asio_result!(ai::ASIOStop())?;
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}
self.set_state(DriverState::Prepared);
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}
Ok(())
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}
/// Adds a callback to the list of active callbacks.
///
/// The given function receives the index of the buffer currently ready for processing.
pub fn set_callback<F>(&self, callback: F)
where
F: 'static + FnMut(i32) + Send,
{
let mut bc = BUFFER_CALLBACK.lock().unwrap();
bc.push(Some(BufferCallback(Box::new(callback))));
}
/// Consumes and destroys the `Driver`, stopping the streams if they are running and releasing
/// any associated resources.
pub fn destroy(mut self) -> Result<(), AsioError> {
self.destroy_inner()
}
fn destroy_inner(&mut self) -> Result<(), AsioError> {
// Drop back through the driver state machine one state at a time.
if let DriverState::Running = self.state() {
self.stop().expect("failed to stop ASIO driver");
}
if let DriverState::Prepared = self.state() {
self.dispose_buffers().expect("failed to dispose buffers of ASIO driver");
}
unsafe {
asio_result!(ai::ASIOExit())?;
ai::remove_current_driver();
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}
// Clear any existing stream callbacks.
if let Ok(mut bcs) = BUFFER_CALLBACK.lock() {
bcs.clear();
}
// Indicate to the
self.loaded.store(false, atomic::Ordering::SeqCst);
Ok(())
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}
}
impl Drop for Driver {
fn drop(&mut self) {
if self.loaded.load(atomic::Ordering::SeqCst) {
// We probably shouldn't `panic!` in the destructor? We also shouldn't ignore errors
// though either.
self.destroy_inner().ok();
}
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}
}
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unsafe impl Send for AsioStream {}
/// Idicates the sample rate has changed
/// TODO Change the sample rate when this
/// is called.
extern "C" fn sample_rate_did_change(_s_rate: c_double) -> () {}
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/// Messages for ASIO
/// This is not currently used
extern "C" fn asio_message(
_selector: c_long, _value: c_long, _message: *mut (), _opt: *mut c_double,
) -> c_long {
// TODO Impliment this to give proper responses
4 as c_long
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}
/// Similar to buffer switch but with time info
/// Not currently used
extern "C" fn buffer_switch_time_info(
params: *mut ai::ASIOTime, _double_buffer_index: c_long, _direct_process: c_long,
) -> *mut ai::ASIOTime {
params
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}
/// 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) -> () {
// This lock is probably unavoidable
// but locks in the audio stream is not great
let mut bcs = BUFFER_CALLBACK.lock().unwrap();
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for mut bc in bcs.iter_mut() {
if let Some(ref mut bc) = bc {
bc.run(double_buffer_index);
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}
}
}