distinctPairs() and overlappingPairs() should always return a result

Outdooractive · Oct 25, 2023 · 8e9d269 · 8e9d269
1 parent 03a4a1d
commit 8e9d269
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Showing 4 changed files with 25 additions and 13 deletions.
diff --git a/Sources/GISTools/Extensions/ArrayExtensions.swift b/Sources/GISTools/Extensions/ArrayExtensions.swift
@@ -126,9 +126,13 @@ extension Array {
     /// let a = [1, 2, 3, 4, 5]
     /// a.distinctPairs() -> [(1, 2), (3, 4)]
     /// ```
-    func distinctPairs() -> [(first: Element, second: Element)] {
+    func distinctPairs() -> [(first: Element, second: Element?)] {
         guard !isEmpty else { return [] }
 
+        if count == 1 {
+            return [(first: self[0], second: nil)]
+        }
+
         return (0 ..< (self.count / 2)).map { (index) in
             let i = index * 2
             return (first: self[i], second: self[i+1])
@@ -141,9 +145,13 @@ extension Array {
     /// let a = [1, 2, 3, 4, 5]
     /// a.overlappingPairs() -> [(1, 2), (2, 3), (3, 4), (4, 5)]
     /// ```
-    func overlappingPairs() -> [(first: Element, second: Element)] {
+    func overlappingPairs() -> [(first: Element, second: Element?)] {
         guard !isEmpty else { return [] }
 
+        if count == 1 {
+            return [(first: self[0], second: nil)]
+        }
+
         return (0 ..< (self.count - 1)).map { (index) in
             return (first: self[index], second: self[index + 1])
         }

diff --git a/Sources/GISTools/GeoJson/LineString.swift b/Sources/GISTools/GeoJson/LineString.swift
@@ -74,11 +74,13 @@ public struct LineString:
                 }
             }
 
-            if current.first != previous.second {
-                coordinates.append(current.first)
-            }
-            if current.second != current.first {
-                coordinates.append(current.second)
+            if let current {
+                if current.first != previous.second {
+                    coordinates.append(current.first)
+                }
+                if current.second != current.first {
+                    coordinates.append(current.second)
+                }
             }
         }
 

diff --git a/Sources/GISTools/Turf/LineSegments.swift b/Sources/GISTools/Turf/LineSegments.swift
@@ -34,17 +34,19 @@ extension GeoJson {
             return []
 
         case let lineString as LineString:
-            return lineString.coordinates.overlappingPairs().map { (first, second) in
-                LineSegment(first: first, second: second)
+            return lineString.coordinates.overlappingPairs().compactMap { (first, second) in
+                guard let second else { return nil }
+                return LineSegment(first: first, second: second)
             }
 
         case let multiLineString as MultiLineString:
             return multiLineString.lineStrings.flatMap { $0.lineSegments }
 
         case let polygon as Polygon:
             return polygon.rings.flatMap({ (ring) in
-                ring.coordinates.overlappingPairs().map { (first, second) in
-                    LineSegment(first: first, second: second)
+                ring.coordinates.overlappingPairs().compactMap { (first, second) in
+                    guard let second else { return nil }
+                    return LineSegment(first: first, second: second)
                 }
             })
 

diff --git a/Tests/GISToolsTests/Extensions/ArrayExtensionsTests.swift b/Tests/GISToolsTests/Extensions/ArrayExtensionsTests.swift
@@ -34,7 +34,7 @@ final class ArrayExtensionsTests: XCTestCase {
         let smallPairs = small.distinctPairs()
 
         XCTAssertEqual(emptyPairs.count, 0)
-        XCTAssertEqual(smallPairs.count, 0)
+        XCTAssertEqual(smallPairs.count, 1)
     }
 
     func testOverlappingPairs() {
@@ -76,7 +76,7 @@ final class ArrayExtensionsTests: XCTestCase {
         let smallPairs = small.overlappingPairs()
 
         XCTAssertEqual(emptyPairs.count, 0)
-        XCTAssertEqual(smallPairs.count, 0)
+        XCTAssertEqual(smallPairs.count, 1)
     }
 
     func testGet() {