use crate::{ PacketLine, {DELIMITER_LINE, FLUSH_LINE, MAX_DATA_LEN, MAX_LINE_LEN, RESPONSE_END_LINE, U16_HEX_BYTES},};use bstr::BString;use quick_error::quick_error; quick_error! { #[derive(Debug)] pub enum Error { HexDecode(err: hex::FromHexError) { display("Failed to decode the first four hex bytes indicating the line length") from() source(err) } DataLengthLimitExceeded(length_in_bytes: usize) { display("The data received claims to be larger than than the maximum allowed size: got {}, exceeds {}", length_in_bytes, MAX_DATA_LEN) } DataIsEmpty { display("Received an invalid empty line") } InvalidLineLength { display("Received an invalid line of length 3") } Line(data: BString, bytes_consumed: usize) { display("{}", data) } }} #[derive(Debug, Clone)]pub enum Stream<'a> { Complete { line: PacketLine<'a>, bytes_consumed: usize, }, Incomplete { /// The amount of additional bytes needed for the parsing to complete bytes_needed: usize, },} pub enum PacketLineOrWantedSize<'a> { Line(PacketLine<'a>), Wanted(u16),} pub fn hex_prefix(four_bytes: &[u8]) -> Result<PacketLineOrWantedSize, Error> { debug_assert_eq!(four_bytes.len(), 4, "need four hex bytes"); for (line_bytes, line_type) in &[ (FLUSH_LINE, PacketLine::Flush), (DELIMITER_LINE, PacketLine::Delimiter), (RESPONSE_END_LINE, PacketLine::ResponseEnd), ] { if four_bytes == *line_bytes { return Ok(PacketLineOrWantedSize::Line(*line_type)); } } let mut buf = [0u8; U16_HEX_BYTES / 2]; hex::decode_to_slice(four_bytes, &mut buf)?; let wanted_bytes = u16::from_be_bytes(buf); if wanted_bytes == 3 { return Err(Error::InvalidLineLength); } if wanted_bytes == 4 { return Err(Error::DataIsEmpty); } debug_assert!( wanted_bytes as usize > U16_HEX_BYTES, "by now there should be more wanted bytes than prefix bytes" ); Ok(PacketLineOrWantedSize::Wanted(wanted_bytes - U16_HEX_BYTES as u16))} pub fn to_data_line(data: &[u8]) -> Result<PacketLine, Error> { if data.len() > MAX_LINE_LEN { return Err(Error::DataLengthLimitExceeded(data.len())); } Ok(PacketLine::Data(data))} // TODO: verify this one is actually needed in the endpub 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(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, })}
use crate::{
PacketLine, {DELIMITER_LINE, FLUSH_LINE, MAX_DATA_LEN, MAX_LINE_LEN, RESPONSE_END_LINE, U16_HEX_BYTES},
};
use bstr::BString;
use quick_error::quick_error;
quick_error! {
#[derive(Debug)]
pub enum Error {
HexDecode(err: hex::FromHexError) {
display("Failed to decode the first four hex bytes indicating the line length")
from()
source(err)
}
DataLengthLimitExceeded(length_in_bytes: usize) {
display("The data received claims to be larger than than the maximum allowed size: got {}, exceeds {}", length_in_bytes, MAX_DATA_LEN)
}
DataIsEmpty {
display("Received an invalid empty line")
}
InvalidLineLength {
display("Received an invalid line of length 3")
}
Line(data: BString, bytes_consumed: usize) {
display("{}", data)
}
}
}
#[derive(Debug, Clone)]
pub enum Stream<'a> {
Complete {
line: PacketLine<'a>,
bytes_consumed: usize,
},
Incomplete {
/// The amount of additional bytes needed for the parsing to complete
bytes_needed: usize,
},
}
pub enum PacketLineOrWantedSize<'a> {
Line(PacketLine<'a>),
Wanted(u16),
}
pub fn hex_prefix(four_bytes: &[u8]) -> Result<PacketLineOrWantedSize, Error> {
debug_assert_eq!(four_bytes.len(), 4, "need four hex bytes");
for (line_bytes, line_type) in &[
(FLUSH_LINE, PacketLine::Flush),
(DELIMITER_LINE, PacketLine::Delimiter),
(RESPONSE_END_LINE, PacketLine::ResponseEnd),
] {
if four_bytes == *line_bytes {
return Ok(PacketLineOrWantedSize::Line(*line_type));
}
}
let mut buf = [0u8; U16_HEX_BYTES / 2];
hex::decode_to_slice(four_bytes, &mut buf)?;
let wanted_bytes = u16::from_be_bytes(buf);
if wanted_bytes == 3 {
return Err(Error::InvalidLineLength);
}
if wanted_bytes == 4 {
return Err(Error::DataIsEmpty);
}
debug_assert!(
wanted_bytes as usize > U16_HEX_BYTES,
"by now there should be more wanted bytes than prefix bytes"
);
Ok(PacketLineOrWantedSize::Wanted(wanted_bytes - U16_HEX_BYTES as u16))
}
pub fn to_data_line(data: &[u8]) -> Result<PacketLine, Error> {
if data.len() > MAX_LINE_LEN {
return Err(Error::DataLengthLimitExceeded(data.len()));
}
Ok(PacketLine::Data(data))
}
// TODO: verify this one is actually needed in the end
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(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,
})
}