macro_rules! write_varint_future {
($primitive: ty, $future: ident) => {
write_varint_future!(f cfg(feature = "async_varint"), $primitive, $future, u8, WriteU8Raw);
};
(f $feature: meta, $primitive: ty, $future: ident, $internal: ty, $inner_future: ident) => {
#[$feature]
$crate::pin_project_lite::pin_project! {
#[cfg_attr(docsrs, doc($feature))]
#[derive(Debug)]
#[project(!Unpin)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct $future<'a, W: ?Sized> {
value: $primitive,
position: usize,
ok: bool,
#[pin]
inner: $inner_future<'a, W>,
}
}
#[$feature]
impl<'a, W: ?Sized> WriterFuture<'a, W, $primitive> for $future<'a, W> {
fn new(writer: &'a mut W, buf: $primitive) -> Self {
let (value, current, position) = Self::_extra(buf, 0);
Self { value, position, ok: false, inner: $inner_future::new(writer, current) }
}
fn reset(self: Pin<&mut Self>, buf: $primitive) {
let me = self.project();
let (value, current, position) = Self::_extra(buf, 0);
*me.value = value;
*me.position = position;
*me.ok = false;
me.inner.reset(current);
}
}
#[$feature]
impl<'a, W: AsyncVariableWriter + Unpin + ?Sized> Future for $future<'a, W> {
type Output = ::core::result::Result<(), W::Error>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let mut me = self.project();
if *me.ok { return Poll::Ready(Ok(())); }
loop {
::core::task::ready!(me.inner.as_mut().poll(cx))?;
if *me.value == 0 {
*me.ok = true;
return Poll::Ready(Ok(()));
}
let (value, current, position) = Self::_extra(*me.value, *me.position);
*me.value = value;
*me.position = position;
me.inner.as_mut().reset(current);
}
}
}
#[$feature]
#[allow(arithmetic_overflow)] impl<'a, W: ?Sized> $future<'a, W> {
fn _extra(value: $primitive, position: usize) -> ($primitive, $internal, usize) {
const NUM_BITS: $internal = <$internal>::MAX >> 1;
const SIGN_BIT: $internal = NUM_BITS + 1;
const POS_OFFSET: usize = (<$internal>::BITS - 1) as usize;
if (value & NUM_BITS as $primitive) != value {
(value >> POS_OFFSET, ((value & (NUM_BITS as $primitive)) as $internal) | SIGN_BIT, position + POS_OFFSET)
} else {
(0, value as $internal, position + POS_OFFSET)
}
}
}
};
}
macro_rules! write_varint_func {
($primitive: ty, $future: ident, $func: ident) => {
write_varint_func!(f cfg(feature = "async_varint"), $primitive, $future, $func);
};
(f $feature: meta, $primitive: ty, $future: ident, $func: ident) => {
write_wrap_func!(f $feature, $primitive, $future, $func);
};
}
macro_rules! define_write_varint_future {
() => {
write_varint_future!(u16, WriteU16Varint);
write_varint_future!(u32, WriteU32Varint);
write_varint_future!(u64, WriteU64Varint);
write_varint_future!(u128, WriteU128Varint);
};
}
macro_rules! define_write_varint_func {
() => {
write_varint_func!(u16, WriteU16Varint, write_u16_varint);
write_varint_func!(u32, WriteU32Varint, write_u32_varint);
write_varint_func!(u64, WriteU64Varint, write_u64_varint);
write_varint_func!(u128, WriteU128Varint, write_u128_varint);
};
}
define_write_varint_future!();
#[cfg(all(feature = "async_varint", not(feature = "async_raw")))]
compile_error!("developer error: please check Cargo.toml");