#[cfg(feature = "nightly")]
use core::mem::MaybeUninit;
#[cfg(feature = "nightly")]
use crate::io::{ErrorKind, Read, Write};
#[cfg(feature = "nightly")]
pub fn copy<R: ?Sized, W: ?Sized, const S: usize>(
reader: &mut R,
writer: &mut W,
) -> crate::io::Result<u64>
where
R: Read,
W: Write,
{
let mut buf = MaybeUninit::<[u8; S]>::uninit();
unsafe {
reader.initializer().initialize(buf.assume_init_mut());
}
let mut written = 0;
loop {
let len = match reader.read(unsafe { buf.assume_init_mut() }) {
Ok(0) => return Ok(written),
Ok(len) => len,
Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
Err(e) => return Err(e),
};
writer.write_all(unsafe { &buf.assume_init_ref()[..len] })?;
written += len as u64;
}
}