[buffer] fix for integer overflow

include/boost/geometry/strategies/cartesian/buffer_end_round.hpp

@@ -24,8 +24,6 @@
 #include <boost/geometry/strategies/buffer.hpp>
 
 
-#include <boost/geometry/io/wkt/wkt.hpp>
-
 namespace boost { namespace geometry
 {
 

include/boost/geometry/strategies/cartesian/buffer_join_miter.hpp

@@ -89,8 +89,8 @@ public:
         // Check the distance ip-vertex (= miter distance)
         // (We calculate it manually (not using Pythagoras strategy) to reuse
         //  dx and dy)
-        coordinate_type const dx = get<0>(p) - get<0>(vertex);
-        coordinate_type const dy = get<1>(p) - get<1>(vertex);
+        promoted_type const dx = get<0>(p) - get<0>(vertex);
+        promoted_type const dy = get<1>(p) - get<1>(vertex);
 
         promoted_type const distance = geometry::math::sqrt(dx * dx + dy * dy);
 

include/boost/geometry/strategies/cartesian/buffer_join_round.hpp

@@ -149,20 +149,8 @@ public :
             return false;
         }
 
-        // Generate 'vectors'
-        coordinate_type vix = (get<0>(ip) - get<0>(vertex));
-        coordinate_type viy = (get<1>(ip) - get<1>(vertex));
-
-        promoted_type length_i = geometry::math::sqrt(vix * vix + viy * viy);
-        DistanceType const bd = geometry::math::abs(buffer_distance);
-        promoted_type prop = bd / length_i;
-
-        Point bp;
-        set<0>(bp, get<0>(vertex) + vix * prop);
-        set<1>(bp, get<1>(vertex) + viy * prop);
-
         range_out.push_back(perp1);
-        generate_points<promoted_type>(vertex, perp1, perp2, bd, range_out);
+        generate_points<promoted_type>(vertex, perp1, perp2, geometry::math::abs(buffer_distance), range_out);
         range_out.push_back(perp2);
         return true;
     }

include/boost/geometry/strategies/cartesian/buffer_join_round_by_divide.hpp

@@ -48,23 +48,21 @@ public :
                 RangeOut& range_out,
                 std::size_t level = 1) const
     {
-        typedef typename coordinate_type<Point>::type coordinate_type;
-
         // Generate 'vectors'
-        coordinate_type const vp1_x = get<0>(p1) - get<0>(vertex);
-        coordinate_type const vp1_y = get<1>(p1) - get<1>(vertex);
+        PromotedType const vp1_x = get<0>(p1) - get<0>(vertex);
+        PromotedType const vp1_y = get<1>(p1) - get<1>(vertex);
 
-        coordinate_type const vp2_x = (get<0>(p2) - get<0>(vertex));
-        coordinate_type const vp2_y = (get<1>(p2) - get<1>(vertex));
+        PromotedType const vp2_x = (get<0>(p2) - get<0>(vertex));
+        PromotedType const vp2_y = (get<1>(p2) - get<1>(vertex));
 
         // Average them to generate vector in between
-        coordinate_type const two = 2;
-        coordinate_type const v_x = (vp1_x + vp2_x) / two;
-        coordinate_type const v_y = (vp1_y + vp2_y) / two;
+        PromotedType const two = 2;
+        PromotedType const v_x = (vp1_x + vp2_x) / two;
+        PromotedType const v_y = (vp1_y + vp2_y) / two;
 
         PromotedType const length2 = geometry::math::sqrt(v_x * v_x + v_y * v_y);
 
-        PromotedType prop = buffer_distance / length2;
+        PromotedType const prop = buffer_distance / length2;
 
         Point mid_point;
         set<0>(mid_point, get<0>(vertex) + v_x * prop);
@@ -106,13 +104,13 @@ public :
         }
 
         // Generate 'vectors'
-        coordinate_type const vix = (get<0>(ip) - get<0>(vertex));
-        coordinate_type const viy = (get<1>(ip) - get<1>(vertex));
+        promoted_type const vix = (get<0>(ip) - get<0>(vertex));
+        promoted_type const viy = (get<1>(ip) - get<1>(vertex));
 
         promoted_type const length_i = geometry::math::sqrt(vix * vix + viy * viy);
 
         promoted_type const bd = geometry::math::abs(buffer_distance);
-        promoted_type prop = bd / length_i;
+        promoted_type const prop = bd / length_i;
 
         Point bp;
         set<0>(bp, get<0>(vertex) + vix * prop);

include/boost/geometry/strategies/cartesian/buffer_side_straight.hpp

@@ -76,8 +76,8 @@ public :
         // Generate a block along (left or right of) the segment
 
         // Simulate a vector d (dx,dy)
-        coordinate_type const dx = get<0>(input_p2) - get<0>(input_p1);
-        coordinate_type const dy = get<1>(input_p2) - get<1>(input_p1);
+        promoted_type const dx = get<0>(input_p2) - get<0>(input_p1);
+        promoted_type const dy = get<1>(input_p2) - get<1>(input_p1);
 
         // For normalization [0,1] (=dot product d.d, sqrt)
         promoted_type const length = geometry::math::sqrt(dx * dx + dy * dy);

test/strategies/Jamfile

@@ -18,6 +18,8 @@
 test-suite boost-geometry-strategies
     :
     [ run andoyer.cpp                        : : : : strategies_andoyer ]
+    [ run buffer_join.cpp                    : : : : strategies_buffer_join ]
+    [ run buffer_side_straight.cpp           : : : : strategies_buffer_side_straight ]
     [ run cross_track.cpp                    : : : : strategies_cross_track ]
     [ run crossings_multiply.cpp             : : : : strategies_crossings_multiply ]
     [ run distance_default_result.cpp        : : : : strategies_distance_default_result ]

test/strategies/buffer_join.cpp

@@ -0,0 +1,87 @@
+// Boost.Geometry
+// Unit Test
+
+// Copyright (c) 2022 Barend Gehrels, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <geometry_test_common.hpp>
+
+#include <boost/geometry/geometries/point.hpp>
+#include <boost/geometry/geometries/ring.hpp>
+#include <boost/geometry/strategies/cartesian/buffer_join_round.hpp>
+#include <boost/geometry/strategies/cartesian/buffer_join_round_by_divide.hpp>
+#include <boost/geometry/io/wkt/wkt.hpp>
+#include <boost/geometry/algorithms/area.hpp>
+#include <boost/geometry/algorithms/distance.hpp>
+#include <boost/geometry/algorithms/equals.hpp>
+
+template <typename JoinStrategy, typename P, typename T>
+void test_join(JoinStrategy const& join,
+               P const& ip, P const& vertex,
+               P const& perp1, P const& perp2,
+               T const& buffer_distance, std::size_t expected_size)
+{
+    // Use a deque to be able to use push_front
+    bg::model::ring<P, true, true, std::deque> output_ring;
+
+    auto const result = join.apply(ip, vertex, perp1, perp2, buffer_distance, output_ring);
+    BOOST_CHECK_EQUAL(true, result);
+    BOOST_CHECK_EQUAL(expected_size , output_ring.size());
+    BOOST_CHECK(bg::equals(perp1, output_ring.front()));
+    BOOST_CHECK(bg::equals(perp2, output_ring.back()));
+
+    // All the generated points should be located
+    // at or close to the specified buffer distance from the vertex
+    for (const auto& p : output_ring)
+    {
+        auto const d = bg::distance(vertex, p);
+        auto const fraction = d / buffer_distance;
+        BOOST_CHECK_MESSAGE(fraction > 0.92 && fraction < 1.02,
+            "Unexpected distance = " << d << " fraction=" << fraction);
+    }
+
+    // Start with the vertex itself, and close it,
+    // to calculate the area of the buffered corner
+    output_ring.push_front(vertex);
+    output_ring.push_back(vertex);
+
+    // Area should be around 0.25 * PI * sqr(specified buffer distance)
+    // It is a bit less because there are less than infinite points in the circle
+    double const area = bg::area(output_ring) ;
+    double const expected = 0.25 * buffer_distance * buffer_distance * 3.1415;
+    double const fraction_area = area / expected;
+    BOOST_CHECK_MESSAGE(fraction_area > 0.95 && fraction_area < 1.05,
+        "Unexpected area = " << area << " fraction=" << fraction_area);
+}
+
+template <typename P>
+void test_case(typename bg::coordinate_type<P>::type c)
+{
+    // For round strategy (36 points per circle) we expect 10 points in a corner.
+    // Using divide on level 3, we get 17
+    test_join(bg::strategy::buffer::join_round(36), P{c, c}, P{0, 0}, P{0, c}, P{c, 0}, double(c), 10);
+    test_join(bg::strategy::buffer::join_round_by_divide(3), P{c, c}, P{0, 0}, P{0, c}, P{c, 0}, double(c), 17);
+}
+
+template <typename P>
+void test_all()
+{
+    // Also test for large coordinates.
+    // For integer coordinates there was an overflow with them (now fixed)
+    test_case<P>(100);
+    test_case<P>(10000);
+    test_case<P>(1000000);
+    test_case<P>(100000000);
+}
+
+int test_main(int, char *[])
+{
+    test_all<bg::model::point<int, 2, bg::cs::cartesian>>();
+    test_all<bg::model::point<float, 2, bg::cs::cartesian>>();
+    test_all<bg::model::point<double, 2, bg::cs::cartesian>>();
+
+    return 0;
+}

test/strategies/buffer_side_straight.cpp

@@ -0,0 +1,59 @@
+// Boost.Geometry
+// Unit Test
+
+// Copyright (c) 2022 Barend Gehrels, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <geometry_test_common.hpp>
+
+#include <boost/geometry/geometries/point.hpp>
+
+#include <boost/geometry/strategies/cartesian/buffer_side_straight.hpp>
+#include <boost/geometry/strategies/agnostic/buffer_distance_symmetric.hpp>
+
+#include <boost/geometry/algorithms/distance.hpp>
+
+template <typename P>
+void test_side_straight(P const &input_p1, P const &input_p2)
+{
+    using bg::strategy::buffer::side_straight;
+
+    bg::strategy::buffer::distance_symmetric<typename bg::coordinate_type<P>::type> ds(1.0);
+
+    std::vector<P> output_range;
+
+    auto const result = side_straight::apply(input_p1, input_p2, bg::strategy::buffer::buffer_side_right, ds, output_range);
+
+    BOOST_CHECK_EQUAL(bg::strategy::buffer::result_normal, result);
+    BOOST_CHECK_EQUAL(2u, output_range.size());
+
+#ifdef BOOST_GEOMETRY_TEST_DEBUG
+    if (output_range.size() == 2)
+    {
+        std::cout << bg::distance(output_range.front(), output_range.back()) << std::endl;
+    }
+#endif
+}
+
+template <typename P>
+void test_all()
+{
+    // Also test for large coordinates.
+    // For integer coordinates there was an overflow with them (now fixed)
+    test_side_straight(P{0, 0}, P{1, 1});
+    test_side_straight(P{0, 0}, P{100, 100});
+    test_side_straight(P{0, 0}, P{10000, 10000});
+    test_side_straight(P{0, 0}, P{1000000, 1000000});
+    test_side_straight(P{0, 0}, P{100000000, 100000000});
+}
+
+int test_main(int, char *[])
+{
+    test_all<bg::model::point<int, 2, bg::cs::cartesian>>();
+    test_all<bg::model::point<double, 2, bg::cs::cartesian>>();
+
+    return 0;
+}