Add HDT sentence parser

README.md

@@ -21,6 +21,7 @@ NMEA Standard Sentences
 - GNS *
 - GSA *
 - GSV *
+- HDT
 - MDA
 - MTW
 - MWV

src/lib.rs

@@ -19,6 +19,7 @@
 //! - GNS *
 //! - GSA *
 //! - GSV *
+//! - HDT
 //! - MDA
 //! - MWV
 //! - RMC *

src/parse.rs

@@ -107,6 +107,7 @@ pub enum ParseResult {
     GNS(GnsData),
     GSA(GsaData),
     GSV(GsvData),
+    HDT(HdtData),
     MDA(MdaData),
     MTW(MtwData),
     MWV(MwvData),
@@ -131,6 +132,7 @@ impl From<&ParseResult> for SentenceType {
             ParseResult::GNS(_) => SentenceType::GNS,
             ParseResult::GSA(_) => SentenceType::GSA,
             ParseResult::GSV(_) => SentenceType::GSV,
+            ParseResult::HDT(_) => SentenceType::HDT,
             ParseResult::MDA(_) => SentenceType::MDA,
             ParseResult::MTW(_) => SentenceType::MTW,
             ParseResult::MWV(_) => SentenceType::MWV,
@@ -178,6 +180,7 @@ pub fn parse_str(sentence_input: &str) -> Result<ParseResult, Error> {
             SentenceType::GBS => parse_gbs(nmea_sentence).map(ParseResult::GBS),
             SentenceType::GGA => parse_gga(nmea_sentence).map(ParseResult::GGA),
             SentenceType::GSV => parse_gsv(nmea_sentence).map(ParseResult::GSV),
+            SentenceType::HDT => parse_hdt(nmea_sentence).map(ParseResult::HDT),
             SentenceType::RMC => parse_rmc(nmea_sentence).map(ParseResult::RMC),
             SentenceType::GSA => parse_gsa(nmea_sentence).map(ParseResult::GSA),
             SentenceType::VTG => parse_vtg(nmea_sentence).map(ParseResult::VTG),

src/parser.rs

@@ -357,6 +357,7 @@ impl<'a> Nmea {
             | ParseResult::GBS(_)
             | ParseResult::AAM(_)
             | ParseResult::ALM(_)
+            | ParseResult::HDT(_)
             | ParseResult::PGRMZ(_)
             | ParseResult::MTW(_)
             | ParseResult::MWV(_)

src/sentences/hdt.rs

@@ -0,0 +1,84 @@
+use nom::{
+    bytes::complete::take_until,
+    character::complete::char,
+    combinator::{map_res, opt},
+    IResult,
+};
+
+use super::utils::parse_float_num;
+use crate::{Error, NmeaSentence, SentenceType};
+
+/// HDT - Heading - True
+///
+/// <https://gpsd.gitlab.io/gpsd/NMEA.html#_hdt_heading_true>
+///
+/// ```text
+///        1   2 3
+///        |   | |
+/// $--HDT,x.x,T*hh<CR><LF>
+/// ```
+/// 1. Heading, degrees True
+/// 2. T = True
+/// 3. Checksum
+#[derive(Debug, PartialEq)]
+pub struct HdtData {
+    /// Heading, degrees True
+    pub heading: Option<f32>,
+}
+
+/// # Parse HDT message
+///
+/// From gpsd/driver_nmea0183.c
+///
+/// ```text
+/// $HEHDT,341.8,T*21
+///
+/// HDT,x.x*hh<cr><lf>
+/// ```
+///
+/// The only data field is true heading in degrees.
+/// The following field is required to be 'T' indicating a true heading.
+/// It is followed by a mandatory nmea_checksum.
+pub fn parse_hdt(sentence: NmeaSentence) -> Result<HdtData, Error> {
+    if sentence.message_id != SentenceType::HDT {
+        Err(Error::WrongSentenceHeader {
+            expected: SentenceType::HDT,
+            found: sentence.message_id,
+        })
+    } else {
+        Ok(do_parse_hdt(sentence.data)?.1)
+    }
+}
+
+fn do_parse_hdt(i: &str) -> IResult<&str, HdtData> {
+    let (i, heading) = opt(map_res(take_until(","), parse_float_num::<f32>))(i)?;
+    let (i, _) = char(',')(i)?;
+    let (i, _) = char('T')(i)?;
+    Ok((i, HdtData { heading }))
+}
+
+#[cfg(test)]
+mod tests {
+    use approx::assert_relative_eq;
+
+    use super::*;
+    use crate::parse::parse_nmea_sentence;
+
+    #[test]
+    fn test_parse_hdt_full() {
+        let data = parse_hdt(NmeaSentence {
+            talker_id: "GP",
+            message_id: SentenceType::HDT,
+            data: "274.07,T",
+            checksum: 0x03,
+        })
+        .unwrap();
+        assert_relative_eq!(data.heading.unwrap(), 274.07);
+
+        let s = parse_nmea_sentence("$GPHDT,,T*1B").unwrap();
+        assert_eq!(s.checksum, s.calc_checksum());
+
+        let data = parse_hdt(s);
+        assert_eq!(data, Ok(HdtData { heading: None }));
+    }
+}

src/sentences/mod.rs

@@ -10,6 +10,7 @@ mod gll;
 mod gns;
 mod gsa;
 mod gsv;
+mod hdt;
 mod mda;
 mod mtw;
 mod mwv;
@@ -37,6 +38,7 @@ pub use {
     gnss_type::GnssType,
     gsa::{parse_gsa, GsaData},
     gsv::{parse_gsv, GsvData},
+    hdt::{parse_hdt, HdtData},
     mda::{parse_mda, MdaData},
     mtw::{parse_mtw, MtwData, MtwUnit},
     mwv::{parse_mwv, MwvData, MwvReference, MwvWindSpeedUnits},

tests/all_supported_messages.rs

@@ -21,6 +21,8 @@ fn test_all_supported_messages() {
         (SentenceType::GSA, "$GPGSA,A,3,23,31,22,16,03,07,,,,,,,1.8,1.1,1.4*3E"),
         // GSV
         (SentenceType::GSV, "$GPGSV,3,1,12,01,49,196,41,03,71,278,32,06,02,323,27,11,21,196,39*72"),
+        // HDT
+        (SentenceType::HDT, "$GPHDT,274.07,T*03"),
         // MDA
         (SentenceType::MDA, "$WIMWV,041.1,R,01.0,N,A*16"),
         // MWV