embedded_io_async/impls/
slice_mut.rs

1use core::mem;
2use embedded_io::SliceWriteError;
3
4use crate::Write;
5
6/// Write is implemented for `&mut [u8]` by copying into the slice, overwriting
7/// its data.
8///
9/// Note that writing updates the slice to point to the yet unwritten part.
10/// The slice will be empty when it has been completely overwritten.
11///
12/// If the number of bytes to be written exceeds the size of the slice, write operations will
13/// return short writes: ultimately, `Ok(0)`; in this situation, `write_all` returns an error of
14/// kind `ErrorKind::WriteZero`.
15impl Write for &mut [u8] {
16    #[inline]
17    async fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
18        let amt = core::cmp::min(buf.len(), self.len());
19        if !buf.is_empty() && amt == 0 {
20            return Err(SliceWriteError::Full);
21        }
22        let (a, b) = mem::take(self).split_at_mut(amt);
23        a.copy_from_slice(&buf[..amt]);
24        *self = b;
25        Ok(amt)
26    }
27}