progress

gpx-rs/engine/src/core/gpx/categories.rs

@@ -0,0 +1,90 @@
+/// Maps the values of a category of trackpoint data (the surface, the highway...) to small codes,
+/// so that the trackpoints only hold a `u8` instead of a string.
+///
+/// The codes are the positions of the names in the order of first appearance. The table only
+/// grows: a code never changes meaning, so it stays valid in every state of the history.
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct Categories(Vec<String>);
+
+impl Categories {
+    /// Maximum number of distinct values.
+    pub const CAPACITY: usize = u8::MAX as usize;
+
+    /// The code of `name`, which is added to the table if it is new. `None` if the table is full.
+    pub fn code(&mut self, name: &str) -> Option<u8> {
+        let index = match self.0.iter().position(|known| known == name) {
+            Some(index) => index,
+            None if self.0.len() < Self::CAPACITY => {
+                self.0.push(name.to_owned());
+                self.0.len() - 1
+            }
+            None => return None,
+        };
+        u8::try_from(index).ok()
+    }
+
+    /// The name of a code, `None` if it is unknown.
+    pub fn name(&self, code: u8) -> Option<&str> {
+        self.0.get(usize::from(code)).map(String::as_str)
+    }
+
+    /// All the names, in the order of their codes.
+    pub fn names(&self) -> &[String] {
+        &self.0
+    }
+}
+
+/// The categories of the data of the trackpoints. There is one table per engine, shared by all
+/// its files.
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct TrackpointCategories {
+    pub surface: Categories,
+    pub highway: Categories,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_codes_follow_the_order_of_appearance() {
+        let mut categories = Categories::default();
+        assert_eq!(categories.code("asphalt"), Some(0));
+        assert_eq!(categories.code("gravel"), Some(1));
+        // a known name keeps its code
+        assert_eq!(categories.code("asphalt"), Some(0));
+        assert_eq!(categories.names(), ["asphalt", "gravel"]);
+    }
+
+    #[test]
+    fn test_names_of_codes() {
+        let mut categories = Categories::default();
+        let code = categories.code("asphalt").unwrap();
+        assert_eq!(categories.name(code), Some("asphalt"));
+        assert_eq!(categories.name(code + 1), None);
+        assert_eq!(Categories::default().name(0), None);
+    }
+
+    #[test]
+    fn test_a_full_table_gives_no_code_to_new_names() {
+        let mut categories = Categories::default();
+        for i in 0..Categories::CAPACITY {
+            assert_eq!(categories.code(&i.to_string()), Some(i as u8));
+        }
+        assert_eq!(categories.code("one too many"), None);
+        assert_eq!(categories.names().len(), Categories::CAPACITY);
+        // the known ones still have their code, the last one included
+        assert_eq!(categories.code("0"), Some(0));
+        assert_eq!(categories.code("254"), Some(254));
+        assert_eq!(categories.name(254), Some("254"));
+    }
+
+    #[test]
+    fn test_the_categories_are_independent() {
+        let mut categories = TrackpointCategories::default();
+        categories.surface.code("asphalt");
+        assert_eq!(categories.highway.code("path"), Some(0));
+        assert_eq!(categories.surface.names(), ["asphalt"]);
+        assert_eq!(categories.highway.names(), ["path"]);
+    }
+}

gpx-rs/engine/src/core/gpx/mod.rs

@@ -1,3 +1,4 @@
+mod categories;
 mod chunk;
 mod common;
 mod file;
@@ -6,6 +7,7 @@ mod track;
 mod trackpoint;
 mod waypoint;
 
+pub use categories::*;
 pub use chunk::*;
 pub use common::*;
 pub use file::*;

gpx-rs/engine/src/core/gpx/trackpoint.rs

@@ -9,5 +9,8 @@ pub struct Trackpoint {
     pub hr: Option<u16>,
     pub cad: Option<u16>,
     pub power: Option<u16>,
-    // TODO OSM data? or store intervals at a higher level?
+    /// Code of the surface, see [`crate::TrackpointCategories`].
+    pub surface: Option<u8>,
+    /// Code of the highway, see [`crate::TrackpointCategories`].
+    pub highway: Option<u8>,
 }