Use own proc macro to generate code to deal with packets

.travis.yml

@@ -9,6 +9,9 @@ matrix:
   allow_failures:
     - rust: nightly
   fast_finish: true
+before_script:
+  - rustup component add rustfmt-preview
+  - which rustfmt
 script:
   - cargo test --verbose --workspace
   - cargo test --release --verbose --workspace

ublox/Cargo.toml

@@ -11,12 +11,12 @@ default = []
 serial = ["serialport", "crc"]
 
 [dependencies]
-serde = "1.0"
-serde_derive = "1.0"
-bincode = "1.2.1"
 chrono = "0.4"
-ublox_derive = "0.0.0"
+ublox_derive = "0.0.1"
 serialport = { version = "3.3.0", optional = true }
 crc = { version = "1.8.1", optional = true }
-num-derive = "0.3.0"
-num-traits = "0.2.11"
+bitflags = "1.2.1"
+
+[dev-dependencies]
+rand = "0.7.3"
+cpu-time = "1.0.0"

ublox/examples/serial.rs

@@ -6,24 +6,23 @@ mod serial {
 
     pub fn main() {
         let mut dev = Device::new("/dev/ttyUSB0").unwrap();
-
-        let pos = Position {
-            lon: -97.5,
-            lat: 30.2,
-            alt: 200.0,
-        };
-        println!("Setting AID data...");
-        match dev.load_aid_data(Some(pos), Some(Utc::now())) {
-            Err(e) => {
-                println!("Got error setting AID data: {:?}", e);
-            }
-            _ => {}
-        }
-
+        /*
+                let pos = Position {
+                    lon: -97.5,
+                    lat: 30.2,
+                    alt: 200.0,
+                };
+                println!("Setting AID data...");
+                match dev.load_aid_data(Some(pos), Some(Utc::now())) {
+                    Err(e) => {
+                        println!("Got error setting AID data: {:?}", e);
+                    }
+                    _ => {}
+                }
         loop {
             dev.poll_for(Duration::from_millis(500)).unwrap();
             println!("{:?}", dev.get_solution());
-        }
+        }        */
     }
 }
 

ublox/src/error.rs

@@ -1,25 +1,68 @@
-use std::convert;
-use std::io;
+use std::fmt;
 
 #[derive(Debug)]
-pub enum Error {
-    InvalidChecksum,
-    UnexpectedPacket,
-    TimedOutWaitingForAck(u8, u8),
-    IoError(io::Error),
-    BincodeError(bincode::Error),
+pub enum MemWriterError<E>
+where
+    E: std::error::Error,
+{
+    NotEnoughMem,
+    Custom(E),
 }
 
-impl convert::From<io::Error> for Error {
-    fn from(error: io::Error) -> Self {
-        Error::IoError(error)
+impl<E> fmt::Display for MemWriterError<E>
+where
+    E: std::error::Error,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            MemWriterError::NotEnoughMem => f.write_str("Not enough memory error"),
+            MemWriterError::Custom(e) => write!(f, "MemWriterError: {}", e),
+        }
     }
 }
 
-impl convert::From<bincode::Error> for Error {
-    fn from(error: bincode::Error) -> Self {
-        Error::BincodeError(error)
+impl<E> std::error::Error for MemWriterError<E> where E: std::error::Error {}
+
+/// Error that possible during packets parsing
+#[derive(Debug, PartialEq)]
+pub enum ParserError {
+    InvalidChecksum {
+        expect: u16,
+        got: u16,
+    },
+    InvalidField {
+        packet: &'static str,
+        field: &'static str,
+    },
+    InvalidPacketLen {
+        packet: &'static str,
+        expect: usize,
+        got: usize,
+    },
+}
+
+impl fmt::Display for ParserError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ParserError::InvalidChecksum { expect, got } => write!(
+                f,
+                "Not valid packet's checksum, expect {:x}, got {:x}",
+                expect, got
+            ),
+            ParserError::InvalidField { packet, field } => {
+                write!(f, "Invalid field {} of packet {}", field, packet)
+            }
+            ParserError::InvalidPacketLen {
+                packet,
+                expect,
+                got,
+            } => write!(
+                f,
+                "Invalid packet({}) length, expect {}, got {}",
+                packet, expect, got
+            ),
+        }
     }
 }
 
-pub type Result<T> = std::result::Result<T, Error>;
+impl std::error::Error for ParserError {}

ublox/src/lib.rs

@@ -4,13 +4,16 @@
 //! At time of writing this library is developed for a device which behaves like
 //! a NEO-6M device.
 
-pub use crate::segmenter::Segmenter;
 #[cfg(feature = "serial")]
 pub use crate::serialport::{Device, ResetType};
-pub use crate::ubx_packets::*;
+pub use crate::{
+    error::{MemWriterError, ParserError},
+    parser::{Parser, ParserIter},
+    ubx_packets::*,
+};
 
 mod error;
-mod segmenter;
+mod parser;
 #[cfg(feature = "serial")]
 mod serialport;
 mod ubx_packets;

ublox/src/parser.rs

@@ -0,0 +1,121 @@
+use crate::{
+    error::ParserError,
+    ubx_packets::{match_packet, ubx_checksum, PacketRef, SYNC_CHAR_1, SYNC_CHAR_2},
+};
+
+/// Some big number, TODO: need validation against all known packets
+const MAX_PACK_LEN: usize = 1022;
+
+/// Streaming parser for UBX protocol with buffer
+#[derive(Default)]
+pub struct Parser {
+    buf: Vec<u8>,
+}
+
+impl Parser {
+    pub fn is_buffer_empty(&self) -> bool {
+        self.buf.is_empty()
+    }
+    pub fn buffer_len(&self) -> usize {
+        self.buf.len()
+    }
+    pub fn consume<'a, 'b, 'c>(&'a mut self, new_data: &'b [u8]) -> ParserIter<'c>
+    where
+        'a: 'c,
+    {
+        match self
+            .buf
+            .iter()
+            .chain(new_data.iter())
+            .position(|x| *x == SYNC_CHAR_1)
+        {
+            Some(mut off) => {
+                if off >= self.buf.len() {
+                    off -= self.buf.len();
+                    self.buf.clear();
+                    self.buf.extend_from_slice(&new_data[off..]);
+                    off = 0;
+                } else {
+                    self.buf.extend_from_slice(new_data);
+                }
+                ParserIter {
+                    buf: &mut self.buf,
+                    off,
+                }
+            }
+            None => {
+                self.buf.clear();
+                ParserIter {
+                    buf: &mut self.buf,
+                    off: 0,
+                }
+            }
+        }
+    }
+}
+
+/// Iterator over data stored in `Parser` buffer
+pub struct ParserIter<'a> {
+    buf: &'a mut Vec<u8>,
+    off: usize,
+}
+
+impl<'a> Drop for ParserIter<'a> {
+    fn drop(&mut self) {
+        if self.off <= self.buf.len() {
+            self.buf.drain(0..self.off);
+        }
+    }
+}
+
+impl<'a> ParserIter<'a> {
+    /// Analog of `core::iter::Iterator::next`, should be switched to
+    /// trait implmentation after merge of https://github.com/rust-lang/rust/issues/44265
+    pub fn next(&mut self) -> Option<Result<PacketRef, ParserError>> {
+        while self.off < self.buf.len() {
+            let data = &self.buf[self.off..];
+            let pos = match data.iter().position(|x| *x == SYNC_CHAR_1) {
+                Some(x) => x,
+                None => return None,
+            };
+
+            if (pos + 1) >= data.len() {
+                return None;
+            }
+            if data[pos + 1] != SYNC_CHAR_2 {
+                self.off += pos + 1;
+                continue;
+            }
+
+            if (pos + 5) >= data.len() {
+                return None;
+            }
+
+            let pack_len: usize = u16::from_le_bytes([data[pos + 4], data[pos + 5]]).into();
+            if pack_len > MAX_PACK_LEN {
+                self.off += pos + 1;
+                continue;
+            }
+            if (pos + pack_len + 6 + 2 - 1) >= data.len() {
+                return None;
+            }
+            let (ck_a, ck_b) = ubx_checksum(&data[(pos + 2)..(pos + pack_len + 4 + 2)]);
+
+            let (expect_ck_a, expect_ck_b) =
+                (data[pos + 6 + pack_len], data[pos + 6 + pack_len + 1]);
+            if (ck_a, ck_b) != (expect_ck_a, expect_ck_b) {
+                self.off += pos + 2;
+                return Some(Err(ParserError::InvalidChecksum {
+                    expect: u16::from_le_bytes([expect_ck_a, expect_ck_b]),
+                    got: u16::from_le_bytes([ck_a, ck_b]),
+                }));
+            }
+            let msg_data = &data[(pos + 6)..(pos + 6 + pack_len)];
+            let class_id = data[pos + 2];
+            let msg_id = data[pos + 3];
+            self.off += pos + 6 + pack_len + 2;
+            return Some(match_packet(class_id, msg_id, msg_data));
+        }
+        None
+    }
+}