Function git_packetline::decode::hex_prefix

source · 
pub fn hex_prefix(
    four_bytes: &[u8]
) -> Result<PacketLineOrWantedSize<'_>, Error>
Expand description

Decode the four_bytes packet line prefix provided in hexadecimal form and check it for validity.

Examples found in repository?
src/read/blocking_io.rs (line 19)
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    fn read_line_inner<'a>(reader: &mut T, buf: &'a mut [u8]) -> io::Result<Result<PacketLineRef<'a>, decode::Error>> {
        let (hex_bytes, data_bytes) = buf.split_at_mut(4);
        reader.read_exact(hex_bytes)?;
        let num_data_bytes = match decode::hex_prefix(hex_bytes) {
            Ok(decode::PacketLineOrWantedSize::Line(line)) => return Ok(Ok(line)),
            Ok(decode::PacketLineOrWantedSize::Wanted(additional_bytes)) => additional_bytes as usize,
            Err(err) => return Ok(Err(err)),
        };

        let (data_bytes, _) = data_bytes.split_at_mut(num_data_bytes);
        reader.read_exact(data_bytes)?;
        match decode::to_data_line(data_bytes) {
            Ok(line) => Ok(Ok(line)),
            Err(err) => Ok(Err(err)),
        }
    }
More examples
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src/decode.rs (line 110)
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pub fn streaming(data: &[u8]) -> Result<Stream<'_>, Error> {
    let data_len = data.len();
    if data_len < U16_HEX_BYTES {
        return Ok(Stream::Incomplete {
            bytes_needed: U16_HEX_BYTES - data_len,
        });
    }
    let wanted_bytes = match hex_prefix(&data[..U16_HEX_BYTES])? {
        PacketLineOrWantedSize::Wanted(s) => s as usize,
        PacketLineOrWantedSize::Line(line) => {
            return Ok(Stream::Complete {
                line,
                bytes_consumed: 4,
            })
        }
    } + U16_HEX_BYTES;
    if wanted_bytes > MAX_LINE_LEN {
        return Err(Error::DataLengthLimitExceeded {
            length_in_bytes: wanted_bytes,
        });
    }
    if data_len < wanted_bytes {
        return Ok(Stream::Incomplete {
            bytes_needed: wanted_bytes - data_len,
        });
    }

    Ok(Stream::Complete {
        line: to_data_line(&data[U16_HEX_BYTES..wanted_bytes])?,
        bytes_consumed: wanted_bytes,
    })
}