Merge pull request #92 from google/recovery-rust

Fix recovery bug in Rust

Author: drinckes

rust/src/interface.rs

@@ -272,23 +272,23 @@ pub fn recover_nearest(_code: &str, ref_pt: Point<f64>) -> Result<String, String
 
     let code_area = decode(code.as_str()).unwrap();
 
-    let area_range = compute_latitude_precision(prefix_len);
-    let area_edge = area_range / 2f64;
+    let resolution = compute_latitude_precision(prefix_len);
+    let half_res = resolution / 2f64;
 
     let mut latitude = code_area.center.lat();
     let mut longitude = code_area.center.lng();
 
-    let latitude_diff = latitude - clip_latitude(ref_pt.lat());
-    if latitude_diff > area_edge {
-        latitude -= area_range;
-    } else if latitude_diff < -area_edge {
-        latitude += area_range;
+    let ref_lat = clip_latitude(ref_pt.lat());
+    let ref_lng = normalize_longitude(ref_pt.lng());
+    if ref_lat + half_res < latitude && latitude - resolution >= -LATITUDE_MAX {
+        latitude -= resolution;
+    } else if ref_lat - half_res > latitude && latitude + resolution <= LATITUDE_MAX {
+        latitude += resolution;
     }
-    let longitude_diff = longitude - normalize_longitude(ref_pt.lng());
-    if longitude_diff > area_edge {
-        longitude -= area_range;
-    } else if longitude_diff < -area_edge {
-        longitude += area_range;
+    if ref_lng + half_res < longitude {
+        longitude -= resolution;
+    } else if ref_lng - half_res > longitude {
+        longitude += resolution;
     }
     Ok(encode(Point::new(longitude, latitude), code_area.code_length))
 }

rust/tests/all_test.rs

@@ -77,13 +77,18 @@ fn shorten_recovery_test() {
         let lat = cols[1].parse::<f64>().unwrap();
         let lng = cols[2].parse::<f64>().unwrap();
         let short_code = cols[3];
-
-        assert_eq!(shorten(full_code, Point::new(lng, lat)).unwrap(), short_code, "shorten");
-        assert_eq!(
-            recover_nearest(short_code, Point::new(lng, lat)),
-            Ok(full_code.to_string()),
-            "recover"
-        );
+        let test_type = cols[4];
+
+        if test_type == "B" || test_type == "S" {
+            assert_eq!(shorten(full_code, Point::new(lng, lat)).unwrap(), short_code, "shorten");
+        }
+        if test_type == "B" || test_type == "R" {
+            assert_eq!(
+                recover_nearest(short_code, Point::new(lng, lat)),
+                Ok(full_code.to_string()),
+                "recover"
+            );
+        }
 
         tested += 1;
     }