Merge pull request #15 from nsforth/12-gpgga-nmea-sentence-is-too-long

Added "strict" feature, enabled by default. If disabled NMEA max sent…

.github/workflows/rust.yml

@@ -2,21 +2,22 @@ name: master
 
 on:
   push:
-    branches: [ "master" ]
+    branches: ["master"]
   pull_request:
-    branches: [ "master" ]
+    branches: ["master"]
 
 env:
   CARGO_TERM_COLOR: always
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
-    - name: Build
-      run: cargo build --verbose
-    - name: Run tests
-      run: cargo test --verbose --features mtk
+      - uses: actions/checkout@v4
+      - name: Build
+        run: cargo build --verbose
+      - name: Run tests strict
+        run: cargo test --no-default-features -F mtk,strict
+      - name: Run tests non strict
+        run: cargo test --no-default-features -F mtk

Cargo.toml

@@ -14,12 +14,13 @@ readme = "README.md"
 [dependencies]
 
 [features]
-default = []
+default = ["strict"]
 mtk = []
+strict = []
 
 [badges]
 travis-ci = { repository = "nsforth/nmea0183", branch = "v0.4.0" }
-codecov = { repository = "nsforth/nmea0183"}
+codecov = { repository = "nsforth/nmea0183" }
 is-it-maintained-issue-resolution = { repository = "nsforth/nmea0183" }
 is-it-maintained-open-issues = { repository = "nsforth/nmea0183" }
 maintenance = { status = "actively-developed" }

README.md

@@ -13,6 +13,7 @@ You do not need to do any preprocessing such as split data to strings or NMEA se
 # Optional features
 
 Parser supports Mediatek-related PMTKSPF non-standard sentence. It is disabled by default. Use "mtk" feature if you need it.
+If your receives somehow violates NMEA spec, try disable "strict" feature which enabled by default. For example, without "strict" feauture sentence size is set to 120 chars instead of standart NMEA 79 chars.
 
 # Examples
 
@@ -77,5 +78,3 @@ Should not panic. If so please report issue on project page.
 `NMEA format error!` - Possible data corruption. Parser drops all accumulated data and starts seek new sentences.
 
 It's possible to got other very rare error messages that relates to protocol errors. Receivers nowadays mostly do not violate NMEA specs.
-
-

src/lib.rs

@@ -175,8 +175,8 @@ impl TryFrom<&str> for Source {
             "GL" => Ok(Source::GLONASS),
             "GA" => Ok(Source::Gallileo),
             "BD" => Ok(Source::Beidou),
-            "GN" => Ok(Source::GNSS),   
-            #[cfg(feature = "mtk")]     
+            "GN" => Ok(Source::GNSS),
+            #[cfg(feature = "mtk")]
             "PM" => Ok(Source::MTK),
             _ => Err("Source is not supported!"),
         }
@@ -280,10 +280,18 @@ pub enum ParseResult {
     GSA(Option<GSA>),
 }
 
+#[cfg(feature = "strict")]
+/// Maximum allowed sentence length, according to NMEA 183 docs should be not more than 79 chars. Disable strict feature to parse up to 120 chars.
+pub const MAX_SENTENCE_LENGTH: usize = 79usize;
+
+#[cfg(not(feature = "strict"))]
+/// Maximum allowed sentence length.
+pub const MAX_SENTENCE_LENGTH: usize = 120usize;
+
 /// Parses NMEA sentences and stores intermediate parsing state.
 /// Parser is tolerant for errors so you should not reinitialize it after errors.
 pub struct Parser {
-    buffer: [u8; 79],
+    buffer: [u8; MAX_SENTENCE_LENGTH],
     buflen: usize,
     chksum: u8,
     expected_chksum: u8,
@@ -334,7 +342,7 @@ impl Parser {
     /// Constructs new Parser.
     pub fn new() -> Parser {
         Parser {
-            buffer: [0u8; 79],
+            buffer: [0u8; MAX_SENTENCE_LENGTH],
             buflen: 0,
             chksum: 0,
             expected_chksum: 0,

tests/parsing.rs

@@ -17,6 +17,7 @@ use nmea0183::VTG;
 use nmea0183::{ParseResult, Parser, Source};
 
 #[test]
+#[cfg(feature = "strict")]
 fn test_too_long_sentence() {
     let line = "$01234567890123456789012345678901234567890123456789012345678901234567890123456789";
     let mut caught_error = false;
@@ -33,6 +34,24 @@ fn test_too_long_sentence() {
     assert!(caught_error);
 }
 
+#[test]
+#[cfg(not(feature = "strict"))]
+fn test_too_long_sentence_non_strict() {
+    let line = "$01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890012345678901234567890";
+    let mut caught_error = false;
+    for result in Parser::new().parse_from_bytes(line.as_bytes()) {
+        match result {
+            Ok(_) => continue,
+            Err("NMEA sentence is too long!") => {
+                caught_error = true;
+                break;
+            }
+            Err(_) => panic!("Unexpected error caught in test!"),
+        }
+    }
+    assert!(caught_error);
+}
+
 #[test]
 fn test_correct_but_unsupported_source() {
     let mut p = Parser::new();