Struct ReadChunks 

pub struct ReadChunks<'a, R: ?Sized + Read> { /* private fields */ }

A lending iterator that allows reading chunks of n bytes at a time from a reader.

Implementations

impl<R: Read + ?Sized> ReadChunks<'_, R>

pub fn next_chunk(&mut self) -> Option<Result<&mut [u8]>>

Reads the next chunk of bytes from R with a size n specified by ReadExt::read_chunks.

This method is meant to be called repeatedly until None is returned, at which EOF is assumed to have occurred (when Read::read returns Ok(0)).

Errors

If this function encounters ErrorKind::Interrupted it will continue to attempt to fill the buffer until a different error is encountered, the buffer is filled, or R returns Ok(0).

If a different read error occurs, this function will return the error, and the amount that was read into the internal buffer before the error is unspecified (another call to next_chunk will clobber this data). In the future, a way to extract the leftover buffer after an error may be added. This method was chosen as it mirrors what Read::read_exact does on an error.

Examples

let mut slice: &[u8] = &[0u8, 1, 2, 3];

let mut it = slice.read_chunks(2);

while let Some(chunk) = it.next_chunk() {
    // unwrap the io error, real code should handle this
    let chunk = chunk.unwrap();

    assert!(chunk == &[0, 1] || chunk == &[2, 3]);
}

// The slice implementation of `Read` will empty the slice.
// It is notable that read_chunks did not take ownership of
// slice however, only an exclusive borrow.
assert!(slice.is_empty());