CoordinateSequence: Fix logic error when adding another CoordSeq

dbaston · Sep 22, 2023 · 2499819 · 2499819
1 parent bd633c6
commit 2499819
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/src/geom/CoordinateSequence.cpp b/src/geom/CoordinateSequence.cpp
@@ -191,8 +191,13 @@ CoordinateSequence::add(const CoordinateSequence& cs, std::size_t from, std::siz
         }
     }
 
+    if (first > to) {
+        // No unique points to add.
+        return;
+    }
+
     std::size_t last = first + 1;
-    const CoordinateXY* last_unique = &cs.front<CoordinateXY>();
+    const CoordinateXY* last_unique = &cs.getAt<CoordinateXY>(first);
     while(last <= to) {
         const CoordinateXY* curr = &cs.getAt<CoordinateXY>(last);
         if (curr->equals2D(*last_unique)) {

diff --git a/tests/unit/geom/CoordinateSequenceTest.cpp b/tests/unit/geom/CoordinateSequenceTest.cpp
@@ -1493,4 +1493,21 @@ void object::test<54>
     ensure(xyz3_2.equalsIdentical(xyz3));
 }
 
+
+// test add(CoordinateSequence&, false) when last point of receiving sequence is found after the beginning of donor sequence
+template<>
+template<>
+void object::test<55>
+()
+{
+    CoordinateSequence seq1{CoordinateXY(1,2), CoordinateXY(3, 4)};
+    CoordinateSequence seq2{CoordinateXY(3, 4), CoordinateXY(3, 4), CoordinateXY(5, 6), CoordinateXY(3, 4), CoordinateXY(7, 8), CoordinateXY(7, 8), CoordinateXY(9, 10)};
+
+    CoordinateSequence expected{CoordinateXY(1, 2), CoordinateXY(3, 4), CoordinateXY(5, 6), CoordinateXY(3, 4), CoordinateXY(7, 8), CoordinateXY(9, 10)};
+
+    seq1.add(seq2, false);
+
+    ensure_equals(seq1, expected);
+}
+
 } // namespace tut