feat: add get_feature_as for i32 and i16 support

Use num-traits as direct dependency. geo-types already uses num-traits. Fixes #578

Author: codeart1st

Cargo.lock

@@ -18,7 +18,8 @@ protoc = ["prost-build"]
 protoc-generated = ["prost-build"]
 
 [dependencies]
-geo-types = "0.7"
+geo-types = { version = "0.7", default-features = false }
+num-traits = { version = "0.2", default-features = false, features = ["libm"] }
 prost = { version = "0.13", default-features = false, features = ["prost-derive", "std"] }
 wasm-bindgen = { version = "0.2", optional = true }
 serde-wasm-bindgen = { version = "0.6", optional = true }

Cargo.toml

@@ -9,8 +9,7 @@
 //! - `Feature`: Represents a feature with geometry, an optional id and optional properties.
 
 use std::collections::HashMap;
-
-use geo_types::Geometry;
+use geo_types::{CoordNum, Geometry};
 
 /// An enumeration representing the value of a property associated with a feature.
 #[derive(Debug, Clone, PartialEq, PartialOrd)]
@@ -27,9 +26,9 @@ pub enum Value {
 
 /// A structure representing a feature in a vector tile.
 #[derive(Debug, Clone)]
-pub struct Feature {
+pub struct Feature<T: CoordNum = f32> {
   /// The geometry of the feature.
-  pub geometry: Geometry<f32>,
+  pub geometry: Geometry<T>,
 
   /// Optional identifier for the feature.
   pub id: Option<u64>,
@@ -38,7 +37,7 @@ pub struct Feature {
   pub properties: Option<HashMap<String, Value>>,
 }
 
-impl Feature {
+impl<T: CoordNum> Feature<T> {
   /// Retrieves the geometry of the feature.
   ///
   /// # Returns
@@ -60,7 +59,7 @@ impl Feature {
   /// let geometry = feature.get_geometry();
   /// println!("{:?}", geometry);
   /// ```
-  pub fn get_geometry(&self) -> &Geometry<f32> {
+  pub fn get_geometry(&self) -> &Geometry<T> {
     &self.geometry
   }
 }

src/feature.rs

@@ -73,9 +73,10 @@ mod vector_tile;
 
 use feature::{Feature, Value};
 use geo_types::{
-  Coord, Geometry, LineString, MultiLineString, MultiPoint, MultiPolygon, Point, Polygon,
+  Coord, CoordNum, Geometry, LineString, MultiLineString, MultiPoint, MultiPolygon, Point, Polygon,
 };
 use layer::Layer;
+use num_traits::NumCast;
 use prost::{Message, bytes::Bytes};
 use vector_tile::{Tile, tile::GeomType};
 
@@ -210,6 +211,41 @@ impl Reader {
   /// }
   /// ```
   pub fn get_features(&self, layer_index: usize) -> Result<Vec<Feature>, error::ParserError> {
+    self.get_features_as::<f32>(layer_index)
+  }
+
+  /// Retrieves the features of a specific layer with geometry coordinates in the specified numeric type.
+  ///
+  /// This is a generic version of [`get_features`](Reader::get_features) that allows you to choose
+  /// the coordinate type for the geometry. Supported types include `f32` (default), `i32`, and `i16`.
+  ///
+  /// # Arguments
+  ///
+  /// * `layer_index` - The index of the layer.
+  ///
+  /// # Type Parameters
+  ///
+  /// * `T` - The numeric type for geometry coordinates (e.g. `f32`, `i32`, `i16`).
+  ///
+  /// # Returns
+  ///
+  /// A result containing a vector of features if successful, or a `ParserError` if there is an error parsing the tile or accessing the layer.
+  ///
+  /// # Examples
+  ///
+  /// ```
+  /// use mvt_reader::Reader;
+  ///
+  /// let data = vec![/* Vector tile data */];
+  /// let reader = Reader::new(data).unwrap();
+  ///
+  /// // Get features with i32 coordinates
+  /// let features = reader.get_features_as::<i32>(0);
+  ///
+  /// // Get features with i16 coordinates
+  /// let features = reader.get_features_as::<i16>(0);
+  /// ```
+  pub fn get_features_as<T: CoordNum>(&self, layer_index: usize) -> Result<Vec<Feature<T>>, error::ParserError> {
     let layer = self.tile.layers.get(layer_index);
     match layer {
       Some(layer) => {
@@ -218,7 +254,7 @@ impl Reader {
           if let Some(geom_type) = feature.r#type {
             match GeomType::try_from(geom_type) {
               Ok(geom_type) => {
-                let parsed_geometry = match parse_geometry(&feature.geometry, geom_type) {
+                let parsed_geometry = match parse_geometry::<T>(&feature.geometry, geom_type) {
                   Ok(parsed_geometry) => parsed_geometry,
                   Err(error) => {
                     return Err(error);
@@ -321,29 +357,33 @@ fn map_value(value: vector_tile::tile::Value) -> Value {
   Value::Null
 }
 
-fn shoelace_formula(points: &[Point<f32>]) -> f32 {
+fn shoelace_formula<T: CoordNum>(points: &[Point<T>]) -> f32 {
   let mut area: f32 = 0.0;
   let n = points.len();
   let mut v1 = points[n - 1];
   for v2 in points.iter().take(n) {
-    area += (v2.y() - v1.y()) * (v2.x() + v1.x());
+    let v2y: f32 = NumCast::from(v2.y()).unwrap_or(0.0);
+    let v1y: f32 = NumCast::from(v1.y()).unwrap_or(0.0);
+    let v2x: f32 = NumCast::from(v2.x()).unwrap_or(0.0);
+    let v1x: f32 = NumCast::from(v1.x()).unwrap_or(0.0);
+    area += (v2y - v1y) * (v2x + v1x);
     v1 = *v2;
   }
   area * 0.5
 }
 
-fn parse_geometry(
+fn parse_geometry<T: CoordNum>(
   geometry_data: &[u32],
   geom_type: GeomType,
-) -> Result<Geometry<f32>, error::ParserError> {
+) -> Result<Geometry<T>, error::ParserError> {
   if geom_type == GeomType::Unknown {
     return Err(error::ParserError::new(error::GeometryError::new()));
   }
 
   // worst case capacity to prevent reallocation. not needed to be exact.
-  let mut coordinates: Vec<Coord<f32>> = Vec::with_capacity(geometry_data.len());
-  let mut polygons: Vec<Polygon<f32>> = Vec::new();
-  let mut linestrings: Vec<LineString<f32>> = Vec::new();
+  let mut coordinates: Vec<Coord<T>> = Vec::with_capacity(geometry_data.len());
+  let mut polygons: Vec<Polygon<T>> = Vec::new();
+  let mut linestrings: Vec<LineString<T>> = Vec::new();
 
   let mut cursor: [i32; 2] = [0, 0];
   let mut parameter_count: u32 = 0;
@@ -412,8 +452,8 @@ fn parse_geometry(
           None => i32::MAX, // clip value
         };
         coordinates.push(Coord {
-          x: cursor[0] as f32,
-          y: cursor[1] as f32,
+          x: NumCast::from(cursor[0]).unwrap_or_else(T::zero),
+          y: NumCast::from(cursor[1]).unwrap_or_else(T::zero),
         });
       }
       parameter_count -= 1;

src/lib.rs

@@ -3,6 +3,7 @@ use std::fs::{DirEntry, read, read_dir};
 use std::path::PathBuf;
 use std::{io, result::Result};
 
+use geo_types::CoordNum;
 use mvt_reader::error::TagsError;
 use mvt_reader::{Reader, error::GeometryError};
 
@@ -69,33 +70,37 @@ fn read_corrupted_tags_fixture() -> Result<(), io::Error> {
 }
 
 #[test]
-fn read_all_fixtures() -> Result<(), io::Error> {
+fn read_all_fixtures_f32() -> Result<(), io::Error> {
+  assert_all_fixtures_readable::<f32>("f32")
+}
+
+#[test]
+fn read_all_fixtures_i32() -> Result<(), io::Error> {
+  assert_all_fixtures_readable::<i32>("i32")
+}
+
+#[test]
+fn read_all_fixtures_i16() -> Result<(), io::Error> {
+  assert_all_fixtures_readable::<i16>("i16")
+}
+
+fn assert_all_fixtures_readable<T: CoordNum>(label: &str) -> Result<(), io::Error> {
   for mvt_file in get_all_real_world_fixtures()?.iter() {
     if !mvt_file.extension().unwrap().eq_ignore_ascii_case("mvt") {
       println!("Skipped file {:?}", mvt_file);
       continue;
     }
-    println!("Read {:?}", mvt_file);
+
+    println!("Read {:?} ({})", mvt_file, label);
+
     let bytes = read(mvt_file)?;
-    let reader_result = Reader::new(bytes.to_vec());
-    match reader_result {
-      Ok(reader) => {
-        let layer_names = match reader.get_layer_names() {
-          Ok(layer_names) => layer_names,
-          Err(error) => {
-            panic!("{}", error);
-          }
-        };
-        for (i, _) in layer_names.iter().enumerate() {
-          let features = reader.get_features(i);
-          assert!(!features.unwrap().is_empty());
-        }
-        println!("found layer names: {:?}", layer_names);
-      }
-      Err(_) => {
-        panic!("Parsing failed unexpectedly")
-      }
+    let reader = Reader::new(bytes.to_vec()).expect("Parsing failed unexpectedly");
+    let layer_names = reader.get_layer_names().expect("Failed to get layer names");
+    for (i, _) in layer_names.iter().enumerate() {
+      let features = reader.get_features_as::<T>(i);
+      assert!(!features.unwrap().is_empty());
     }
+    println!("found layer names: {:?}", layer_names);
   }
   Ok(())
 }