Parse the whole packet in one go

Author: Lexicality

src/bin/test_parse.rs

@@ -4,9 +4,7 @@ use std::error;
 
 use winnow::{Bytes, Parser};
 
-use libmbus::parse::application_layer::frame::Frame;
 use libmbus::parse::link_layer::Packet;
-use libmbus::parse::transport_layer::CICode;
 
 fn do_file(fname: &str) -> Result<(), Box<dyn error::Error>> {
 	let data = std::fs::read(fname).map_err(Box::new)?;
@@ -15,24 +13,7 @@ fn do_file(fname: &str) -> Result<(), Box<dyn error::Error>> {
 		.parse(Bytes::new(&data[..]))
 		.map_err(|e| e.into_inner().to_string())?;
 
-	println!("{packet:?}");
-
-	match packet {
-		Packet::Long { data, .. } => {
-			let mut data = Bytes::new(data);
-			let ci = CICode::parse
-				.parse_next(&mut data)
-				.map_err(|e| e.to_string())?;
-			println!("{ci:#?}");
-
-			let frame = Frame::parse
-				.parse(data)
-				.map_err(|e| e.into_inner().to_string())?;
-
-			println!("{frame:#?}");
-		}
-		_ => todo!(),
-	}
+	println!("{packet:#?}");
 	Ok(())
 }
 

src/parse/link_layer.rs

@@ -10,6 +10,7 @@ use winnow::stream::Stream;
 use winnow::Bytes;
 
 use super::error::{MBResult, MBusError};
+use super::transport_layer::MBusMessage;
 
 const LONG_FRAME_HEADER: u8 = 0x68;
 const SHORT_FRAME_HEADER: u8 = 0x10;
@@ -113,7 +114,7 @@ impl Control {
 }
 
 #[derive(Debug)]
-pub enum Packet<'a> {
+pub enum Packet {
 	Ack,
 	Short {
 		control: Control,
@@ -122,11 +123,11 @@ pub enum Packet<'a> {
 	Long {
 		control: Control,
 		address: u8,
-		data: &'a [u8],
+		message: MBusMessage,
 	},
 }
 
-fn parse_variable<'a>(input: &mut &'a Bytes) -> MBResult<Packet<'a>> {
+fn parse_variable(input: &mut &Bytes) -> MBResult<Packet> {
 	let length = binary::u8
 		.context(StrContext::Label("length"))
 		.parse_next(input)?;
@@ -183,14 +184,18 @@ fn parse_variable<'a>(input: &mut &'a Bytes) -> MBResult<Packet<'a>> {
 		);
 	}
 
+	let mut data = Bytes::new(data);
+
+	let message = MBusMessage::parse.parse_next(&mut data)?;
+
 	Ok(Packet::Long {
 		control,
 		address,
-		data,
+		message,
 	})
 }
 
-fn parse_fixed<'a>(input: &mut &'a Bytes) -> MBResult<Packet<'a>> {
+fn parse_fixed(input: &mut &Bytes) -> MBResult<Packet> {
 	// mbus's fixed length datagrams are 2 bytes long, only control & address
 	let ((control, raw_control), address, checksum, _) = (
 		Control::parse
@@ -217,12 +222,12 @@ fn parse_fixed<'a>(input: &mut &'a Bytes) -> MBResult<Packet<'a>> {
 	Ok(Packet::Short { control, address })
 }
 
-fn parse_ack<'a>(_input: &mut &'a Bytes) -> MBResult<Packet<'a>> {
+fn parse_ack(_input: &mut &Bytes) -> MBResult<Packet> {
 	Ok(Packet::Ack)
 }
 
-impl<'a> Packet<'a> {
-	pub fn parse(input: &mut &'a Bytes) -> MBResult<Packet<'a>> {
+impl<'a> Packet {
+	pub fn parse(input: &mut &'a Bytes) -> MBResult<Packet> {
 		alt((
 			preceded(
 				LONG_FRAME_HEADER.void(),

src/parse/transport_layer.rs

@@ -4,4 +4,4 @@ pub mod control_info;
 pub mod header;
 pub mod manufacturer;
 
-pub use control_info::CICode;
+pub use control_info::MBusMessage;

src/parse/transport_layer/control_info.rs

@@ -7,6 +7,7 @@ use winnow::error::StrContext;
 use winnow::prelude::*;
 use winnow::Bytes;
 
+use crate::parse::application_layer::frame::Frame;
 use crate::parse::error::MBResult;
 
 use super::header::LongHeader;
@@ -25,12 +26,12 @@ pub enum BaudRate {
 }
 
 #[derive(Debug)]
-pub enum CICode {
+pub enum MBusMessage {
 	Dlms(u8, TPLHeader), // TODO: Unsupported "see EN 13757–1"
 	Reserved,
 	ApplicationReset(TPLHeader), // or "Select To Device", EN 13757–3:2018, Clause 7
 	CommandToDevice(TPLHeader),  // EN 13757–3:2018, Clause 6
-	ResponseFromDevice(TPLHeader), // EN 13757–3:2018, Clause 6, Annex G
+	ResponseFromDevice(TPLHeader, Frame), // EN 13757–3:2018, Clause 6, Annex G
 	SelectionOfDevice,           // EN 13757-7:2018, Clause 8.4
 	SelectedApplicationRequest(TPLHeader), // EN 13757–3:2018, Clause 7
 	SelectedApplicationResponse(TPLHeader), // EN 13757–3:2018, Clause 7
@@ -48,16 +49,18 @@ pub enum CICode {
 	SecurityTransfer(u8), // TODO: Unsupported - EN 13757–3:2018, Annex A
 }
 
-impl CICode {
-	pub fn parse(input: &mut &Bytes) -> MBResult<CICode> {
+impl MBusMessage {
+	pub fn parse(input: &mut &Bytes) -> MBResult<MBusMessage> {
 		let ci = binary::u8
 			.context(StrContext::Label("CI field"))
 			.parse_next(input)?;
 
-		let mut parse_long_header = LongHeader::parse.context(StrContext::Label("long header"));
+		let parse_long_header = LongHeader::parse.context(StrContext::Label("long header"));
 
 		Ok(match ci {
-			0x72 => CICode::ResponseFromDevice(parse_long_header.parse_next(input)?),
+			0x72 => (parse_long_header, Frame::parse)
+				.map(|(header, frame)| MBusMessage::ResponseFromDevice(header, frame))
+				.parse_next(input)?,
 			_ => todo!(),
 		})
 	}