Message serialization refactoring

build/parser.rs

@@ -182,7 +182,7 @@ impl MavProfile {
             #[allow(unused_imports)]
             use heapless::Vec;
 
-            use crate::{Message, error::*, MAX_FRAME_SIZE, bytes::Bytes, bytes_mut::BytesMut};
+            use crate::{Message, error::*, bytes::Bytes, bytes_mut::BytesMut};
 
             #[cfg(feature = "serde")]
             use serde::{Serialize, Deserialize};
@@ -330,9 +330,9 @@ impl MavProfile {
 
     fn emit_mav_message_serialize(&self, enums: &Vec<TokenStream>) -> TokenStream {
         quote! {
-            fn ser(&self, version: MavlinkVersion) -> BytesMut<MAX_FRAME_SIZE> {
+            fn ser(&self, version: MavlinkVersion, bytes: &mut [u8]) -> usize {
                 match *self {
-                    #(MavMessage::#enums(ref body) => body.ser(version),)*
+                    #(MavMessage::#enums(ref body) => body.ser(version, bytes),)*
                 }
             }
         }
@@ -542,12 +542,14 @@ impl MavMessage {
     fn emit_serialize_vars(&self) -> TokenStream {
         let ser_vars = self.fields.iter().map(|f| f.rust_writer());
         quote! {
-            let mut _tmp = BytesMut::new();
+            let mut _tmp = BytesMut::new(bytes);
             #(#ser_vars)*
             if matches!(version, MavlinkVersion::V2) {
-                crate::remove_trailing_zeroes(&mut _tmp);
+                let len = _tmp.len();
+                crate::remove_trailing_zeroes(&mut bytes[..len])
+            } else {
+                _tmp.len()
             }
-            _tmp
         }
     }
 
@@ -612,7 +614,7 @@ impl MavMessage {
                     #deser_vars
                 }
 
-                pub fn ser(&self, version: MavlinkVersion) -> BytesMut<MAX_FRAME_SIZE> {
+                pub fn ser(&self, version: MavlinkVersion, bytes: &mut [u8]) -> usize {
                     #serialize_vars
                 }
             }

src/bytes_mut.rs

@@ -1,14 +1,11 @@
-pub struct BytesMut<const N: usize> {
-    data: [u8; N],
+pub struct BytesMut<'a> {
+    data: &'a mut [u8],
     len: usize,
 }
 
-impl<const N: usize> BytesMut<N> {
-    pub fn new() -> Self {
-        Self {
-            data: [0; N],
-            len: 0,
-        }
+impl<'a> BytesMut<'a> {
+    pub fn new(data: &'a mut [u8]) -> Self {
+        Self { data, len: 0 }
     }
 
     #[inline]
@@ -18,13 +15,7 @@ impl<const N: usize> BytesMut<N> {
 
     #[inline]
     pub fn remaining(&self) -> usize {
-        N - self.len
-    }
-
-    pub fn set_len(&mut self, len: usize) {
-        assert!(len >= 1);
-        assert!(len <= N);
-        self.len = len;
+        self.data.len() - self.len
     }
 
     #[inline]
@@ -132,12 +123,3 @@ impl<const N: usize> BytesMut<N> {
         self.len += SIZE;
     }
 }
-
-impl<const N: usize> core::ops::Deref for BytesMut<N> {
-    type Target = [u8];
-
-    #[inline]
-    fn deref(&self) -> &[u8] {
-        &self.data[..self.len]
-    }
-}

src/embedded.rs

@@ -1,17 +1,9 @@
-use byteorder::ByteOrder;
-
 use crate::error::*;
 
 /// Replacement for std::io::Read + byteorder::ReadBytesExt in no_std envs
 pub trait Read {
     fn read_u8(&mut self) -> Result<u8, MessageReadError>;
 
-    fn read_u16<B: ByteOrder>(&mut self) -> Result<u16, MessageReadError> {
-        let mut buffer = [0; 2];
-        self.read_exact(&mut buffer)?;
-        Ok(B::read_u16(&buffer))
-    }
-
     fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), MessageReadError> {
         for i in 0..buf.len() {
             buf[i] = self.read_u8()?;
@@ -30,12 +22,6 @@ impl<R: embedded_hal::serial::Read<u8>> Read for R {
 /// Replacement for std::io::Write + byteorder::WriteBytesExt in no_std envs
 pub trait Write {
     fn write_all(&mut self, buf: &[u8]) -> Result<(), MessageWriteError>;
-
-    fn write_u16<B: ByteOrder>(&mut self, n: u16) -> Result<(), MessageWriteError> {
-        let mut buffer = [0; 2];
-        B::write_u16(&mut buffer, n);
-        self.write_all(&buffer)
-    }
 }
 
 impl<W: embedded_hal::serial::Write<u8>> Write for W {