Function file_source::buffer::read_until_with_max_size
source · pub fn read_until_with_max_size<R: BufRead + ?Sized>(
reader: &mut R,
position: &mut FilePosition,
delim: &[u8],
buf: &mut BytesMut,
max_size: usize,
) -> Result<Option<usize>>Expand description
Read up to max_size bytes from reader, splitting by delim
The function reads up to max_size bytes from reader, splitting the input
by delim. If a delim is not found in reader before max_size bytes
are read then the reader is polled until delim is found and the results
are discarded. Else, the result is written into buf.
The return is unusual. In the Err case this function has not written into
buf and the caller should not examine its contents. In the Ok case if the
inner value is None the caller should retry the call as the buffering read
hit the end of the buffer but did not find a delim yet, indicating that
we’ve sheered a write or that there were no bytes available in the reader
and the reader was very sure about it. If the inner value is Some the
interior usize is the number of bytes written into buf.
§Performance
Benchmarks indicate that this function processes in the high single-digit GiB/s range for buffers of length 1KiB. For buffers any smaller than this the overhead of setup dominates our benchmarks.