Fix bugs found with fuzzing

CDT/include/Triangulation.hpp

@@ -566,8 +566,6 @@ void Triangulation<T, TNearPointLocator>::insertEdgeIteration(
     polyR.push_back(iVR);
     outerTrisR.push_back(edgeNeighbor(t, iA, iVR));
     VertInd iV = iA;
-    IndexSizeType nChainedHangingEdgesL = 0;
-    IndexSizeType nChainedHangingEdgesR = 0;
 
     while(!t.containsVertex(iB))
     {
@@ -596,42 +594,14 @@ void Triangulation<T, TNearPointLocator>::insertEdgeIteration(
             locatePointLine(vertices[iVopo], a, b, distanceTolerance);
         if(loc == PtLineLocation::Left)
         {
-            // hanging edge check
-            // previous entry of the vertex in poly if edge is hanging
-            const IndexSizeType prev =
-                (polyL.size() - 2) - 2 * nChainedHangingEdgesL;
-            if(iVopo == polyL[prev])
-            { // hanging edge
-                ++nChainedHangingEdgesL;
-                outerTrisL[prev] = noNeighbor;
-                outerTrisL.push_back(noNeighbor);
-            }
-            else
-            { // normal case
-                nChainedHangingEdgesL = 0;
-                outerTrisL.push_back(edgeNeighbor(tOpo, polyL.back(), iVopo));
-            }
+            outerTrisL.push_back(edgeNeighbor(tOpo, polyL.back(), iVopo));
             polyL.push_back(iVopo);
             iV = iVL;
             iVL = iVopo;
         }
         else if(loc == PtLineLocation::Right)
         {
-            // hanging edge check
-            // previous entry of the vertex in poly if edge is hanging
-            const IndexSizeType prev =
-                (polyR.size() - 2) - 2 * nChainedHangingEdgesR;
-            if(iVopo == polyR[prev])
-            { // hanging edge
-                ++nChainedHangingEdgesR;
-                outerTrisR[prev] = noNeighbor;
-                outerTrisR.push_back(noNeighbor);
-            }
-            else
-            { // normal case
-                nChainedHangingEdgesR = 0;
-                outerTrisR.push_back(edgeNeighbor(tOpo, polyR.back(), iVopo));
-            }
+            outerTrisR.push_back(edgeNeighbor(tOpo, polyR.back(), iVopo));
             polyR.push_back(iVopo);
             iV = iVR;
             iVR = iVopo;
@@ -655,6 +625,15 @@ void Triangulation<T, TNearPointLocator>::insertEdgeIteration(
         pivotVertexTriangleCW(iA);
     if(m_vertTris[iB] == intersected.back())
         pivotVertexTriangleCW(iB);
+    // Handle outer triangles for the cases of hanging edges
+    typedef std::vector<TriInd>::iterator TriIndIt;
+    std::sort(intersected.begin(), intersected.end());
+    for(TriIndIt it = outerTrisR.begin(); it != outerTrisR.end(); ++it)
+        if(std::binary_search(intersected.begin(), intersected.end(), *it))
+            *it = noNeighbor;
+    for(TriIndIt it = outerTrisL.begin(); it != outerTrisL.end(); ++it)
+        if(std::binary_search(intersected.begin(), intersected.end(), *it))
+            *it = noNeighbor;
     // Remove intersected triangles
     typedef std::vector<TriInd>::const_iterator TriIndCit;
     for(TriIndCit it = intersected.begin(); it != intersected.end(); ++it)
@@ -969,6 +948,13 @@ void Triangulation<T, TNearPointLocator>::addSuperTriangle(const Box2d<T>& box)
     const T h = box.max.y - box.min.y;
     T r = std::sqrt(w * w + h * h) / T(2); // incircle radius
     r *= T(1.1);
+
+    // Note: for very large floating point numbers rounding can lead to wrong
+    // super-triangle coordinates. This is a very rare corner-case so the
+    // handling is very primitive.
+    while(center.y <= center.y - r) // '<=' means '==' but avoids the warning
+        r *= T(2);
+
     const T R = T(2) * r;                        // excircle radius
     const T shiftX = R * std::sqrt(T(3)) / T(2); // R * cos(30 deg)
     const V2d<T> posV1 = {center.x - shiftX, center.y - r};

CDT/tests/cdt.test.cpp

@@ -862,3 +862,82 @@ TEST_CASE("Regression test", "")
     cdt.insertEdges(ee);
     REQUIRE(CDT::verifyTopology(cdt));
 }
+
+TEST_CASE("Regression test issue #154 (1)", "")
+{
+    // Very large coordinate values lead to wrong super-triangle coordinates due
+    // to the floating-point rounding
+    auto cdt = Triangulation<double>{};
+    cdt.insertVertices({
+        {0.0, 1e38},
+        {1.0, 1e38},
+    });
+    REQUIRE(CDT::verifyTopology(cdt));
+    const auto outFile = "expected/154_1.txt";
+    if(updateFiles)
+        topologyToFile(outFile, cdt);
+    else
+    {
+        REQUIRE(topologyString(cdt) == topologyString(outFile));
+    }
+}
+
+TEST_CASE("Regression test issue #154 (2)", "")
+{
+    // Explanation: There was an incorrect assumptions that there are no 'loops'
+    // in the pseudo-polygons, only 'hanging' edges. The loops are possible as
+    // shown by this test case.
+    auto cdt = Triangulation<double>{};
+    cdt.insertVertices({
+        {2.0, -2.18933983E-5},
+        {-0.0896810815, -2.18407786E-5},
+        {-2.19008489E-5, -7.64692231E-6},
+        {8.73939061E-5, 0.00568488613},
+        {-0.00142463227, -0.00142461748},
+        {-7.67273832E-6, 8.7602064E-5},
+        {0.00569847599, -0.00142463227},
+        {-2.18156383E-5, -7.6295637E-6},
+    });
+    REQUIRE(CDT::verifyTopology(cdt));
+    cdt.insertEdges({
+        {0, 1},
+    });
+    REQUIRE(CDT::verifyTopology(cdt));
+    const auto outFile = "expected/154_2.txt";
+    if(updateFiles)
+        topologyToFile(outFile, cdt);
+    else
+    {
+        REQUIRE(topologyString(cdt) == topologyString(outFile));
+    }
+}
+
+TEST_CASE("Regression test issue #154 (3)", "")
+{
+    // Explanation: There was an incorrect assumptions that there are no 'loops'
+    // in the pseudo-polygons, only 'hanging' edges. The loops are possible as
+    // shown by this test case.
+    auto cdt = Triangulation<double>{};
+    cdt.insertVertices({
+        {-2.0, 1.47656155},
+        {-6.40527344, -40.4999084},
+        {0.0, -7.96960115},
+        {-2.00152564, 1.46877956},
+        {-2.70361328, -7.99999619},
+        {-2.70465064, -7.99901962},
+        {-7.97778273, -19.3754253},
+        {7.96885204, -5.37488127},
+        {-7.97180128, -39.7499695},
+    });
+    cdt.insertEdges({
+        {0, 8},
+    });
+    REQUIRE(CDT::verifyTopology(cdt));
+    const auto outFile = "expected/154_3.txt";
+    if(updateFiles)
+        topologyToFile(outFile, cdt);
+    else
+    {
+        REQUIRE(topologyString(cdt) == topologyString(outFile));
+    }
+}

CDT/tests/expected/154_1.txt

@@ -0,0 +1,12 @@
+5
+0 1 3   4294967295 3 1
+0 3 2   0 4 4294967295
+1 2 4   4294967295 4 3
+1 4 3   2 4 0
+2 3 4   1 3 2
+
+0
+
+0
+
+0

CDT/tests/expected/154_2.txt

@@ -0,0 +1,25 @@
+17
+0 1 4   4294967295 4 1
+0 4 2   0 6 4294967295
+1 2 3   4294967295 7 3
+1 3 9   2 8 5
+1 7 4   5 14 0
+1 9 7   3 14 4
+2 4 6   1 13 7
+2 6 3   6 10 2
+3 4 9   9 14 3
+3 5 4   12 13 8
+3 6 8   7 15 11
+3 8 10   10 16 12
+3 10 5   11 16 9
+4 5 6   9 15 6
+4 7 9   4 5 8
+5 8 6   16 10 13
+5 10 8   12 11 15
+
+1
+3 4
+
+0
+
+0

CDT/tests/expected/154_3.txt

@@ -0,0 +1,27 @@
+19
+0 1 4   4294967295 6 2
+0 3 2   3 7 4294967295
+0 4 11   0 13 4
+0 9 3   4 11 1
+0 11 9   2 17 3
+1 2 10   4294967295 7 6
+1 10 4   5 14 0
+2 3 10   1 8 5
+3 5 10   10 14 7
+3 6 11   11 17 12
+3 8 5   12 16 8
+3 9 6   3 17 9
+3 11 8   9 18 10
+4 5 11   14 15 2
+4 10 5   6 8 13
+5 7 11   16 18 13
+5 8 7   10 18 15
+6 9 11   11 4 9
+7 8 11   16 12 15
+
+1
+3 11
+
+0
+
+0

docs/README.md

@@ -261,6 +261,7 @@ For work-in-progress on Python bindings check-out [PythonCDT](https://github.com
 - [alkonior](https://github.com/alkonior): finding, reproducing, and reporting a bug ([#142](https://github.com/artem-ogre/CDT/issues/142))
 - [ldcMasa](https://github.com/ldcMasa): finding compilation issue ([#144](https://github.com/artem-ogre/CDT/issues/144))
 - [egladil86](https://github.com/egladil86): finding, reproducing, and reporting a bug ([#148](https://github.com/artem-ogre/CDT/issues/148))
+- [Som1Lse](https://github.com/Som1Lse): fuzzing CDT: finding, reproducing, and reporting bugs ([#154](https://github.com/artem-ogre/CDT/issues/148))
 
 <a name="contributing"></a>