typhoon_utility/bytes/
writer.rs

1use typhoon_errors::ErrorCode;
2
3pub struct MaybeUninitWriter<'a> {
4    buffer: &'a mut [core::mem::MaybeUninit<u8>],
5    position: usize,
6}
7
8impl<'a> MaybeUninitWriter<'a> {
9    #[inline(always)]
10    pub fn new(buffer: &'a mut [core::mem::MaybeUninit<u8>], position: usize) -> Self {
11        Self { buffer, position }
12    }
13
14    #[inline(always)]
15    pub fn initialized(&self) -> &[u8] {
16        unsafe { core::slice::from_raw_parts(self.buffer.as_ptr() as *const u8, self.position) }
17    }
18
19    #[inline(always)]
20    pub fn write_bytes(&mut self, data: &[u8]) -> Result<usize, ErrorCode> {
21        let available = self.buffer.len().saturating_sub(self.position);
22        let to_write = data.len().min(available);
23
24        if to_write == 0 {
25            return Err(ErrorCode::BufferFull);
26        }
27
28        // SAFETY: We're writing to `MaybeUninit` and ensuring the data is valid.
29        unsafe {
30            let dst_ptr = self.buffer.as_mut_ptr().add(self.position);
31            core::ptr::copy_nonoverlapping(data.as_ptr(), dst_ptr as _, to_write);
32        }
33
34        self.position += to_write;
35
36        Ok(to_write)
37    }
38}
39
40#[cfg(feature = "borsh")]
41impl borsh::io::Write for MaybeUninitWriter<'_> {
42    fn write(&mut self, data: &[u8]) -> borsh::io::Result<usize> {
43        self.write_bytes(data)
44            .map_err(|_| borsh::io::Error::new(borsh::io::ErrorKind::WriteZero, "Buffer full"))
45    }
46
47    fn flush(&mut self) -> borsh::io::Result<()> {
48        Ok(())
49    }
50}
typhoon_utility/bytes/writer.rs

typhoon_utility/bytes/
writer.rs
