New function n_points() to get the number of points in any geometry

src/flex-lua-geom.cpp

@@ -114,6 +114,20 @@ int geom_centroid(lua_State *lua_state)
     return 1;
 }
 
+int geom_n_points(lua_State *lua_state)
+{
+    auto const *const input_geometry = unpack_geometry(lua_state);
+
+    try {
+        lua_pushinteger(lua_state,
+                        static_cast<lua_Integer>(input_geometry->n_points()));
+    } catch (...) {
+        return luaL_error(lua_state, "Unknown error in 'n_points()'.\n");
+    }
+
+    return 1;
+}
+
 int geom_geometry_n(lua_State *lua_state)
 {
     auto const *const input_geometry = unpack_geometry(lua_state);
@@ -313,6 +327,7 @@ void init_geometry_class(lua_State *lua_state)
          {"geometry_type", geom_geometry_type},
          {"is_null", geom_is_null},
          {"line_merge", geom_line_merge},
+         {"n_points", geom_n_points},
          {"reverse", geom_reverse},
          {"num_geometries", geom_num_geometries},
          {"pole_of_inaccessibility", geom_pole_of_inaccessibility},

src/geom.cpp

@@ -30,6 +30,25 @@ bool operator!=(polygon_t const &a, polygon_t const &b) noexcept
     return !(a == b);
 }
 
+[[nodiscard]] std::size_t polygon_t::n_points() const
+{
+    return m_outer.size() +
+           std::accumulate(m_inners.cbegin(), m_inners.cend(), std::size_t{0},
+                           [](std::size_t sum, ring_t const &ring) {
+                               return sum + ring.size();
+                           });
+}
+
+[[nodiscard]] std::size_t geometry_t::n_points() const
+{
+    return visit([](auto const &input) { return input.n_points(); });
+}
+
+std::size_t n_points(geometry_t const &geom)
+{
+    return geom.visit([](auto const &input) { return input.n_points(); });
+}
+
 std::size_t dimension(collection_t const &geom)
 {
     return std::accumulate(geom.cbegin(), geom.cend(), 0ULL,

src/geom.hpp

@@ -24,6 +24,7 @@
 #include <cassert>
 #include <cmath>
 #include <initializer_list>
+#include <numeric>
 #include <type_traits>
 #include <utility>
 #include <variant>
@@ -39,6 +40,11 @@ class nullgeom_t
         return 0;
     }
 
+    [[nodiscard]] constexpr static std::size_t n_points() noexcept
+    {
+        return 0;
+    }
+
     [[nodiscard]] constexpr friend bool operator==(nullgeom_t,
                                                    nullgeom_t) noexcept
     {
@@ -69,6 +75,11 @@ class point_t
         return 1;
     }
 
+    [[nodiscard]] constexpr static std::size_t n_points() noexcept
+    {
+        return 1;
+    }
+
     [[nodiscard]] constexpr double x() const noexcept { return m_x; }
     [[nodiscard]] constexpr double y() const noexcept { return m_y; }
 
@@ -148,6 +159,11 @@ class linestring_t : public point_list_t
         return 1;
     }
 
+    [[nodiscard]] std::size_t n_points() const noexcept
+    {
+        return size();
+    }
+
 }; // class linestring_t
 
 class ring_t : public point_list_t
@@ -186,6 +202,8 @@ class polygon_t
 
     friend bool operator!=(polygon_t const &a, polygon_t const &b) noexcept;
 
+    [[nodiscard]] std::size_t n_points() const;
+
 private:
     ring_t m_outer;
     std::vector<ring_t> m_inners;
@@ -257,6 +275,15 @@ class multigeometry_t
 
     void reserve(std::size_t size) { m_geometry.reserve(size); }
 
+    [[nodiscard]] std::size_t n_points() const
+    {
+        return std::accumulate(m_geometry.cbegin(), m_geometry.cend(),
+                               std::size_t{0},
+                               [](std::size_t sum, auto const &geom) {
+                                   return sum + geom.n_points();
+                               });
+    }
+
 private:
     std::vector<GEOM> m_geometry;
 
@@ -400,6 +427,8 @@ class geometry_t
         return !(a == b);
     }
 
+    [[nodiscard]] std::size_t n_points() const;
+
 private:
     std::variant<nullgeom_t, point_t, linestring_t, polygon_t, multipoint_t,
                  multilinestring_t, multipolygon_t, collection_t>

tests/bdd/flex/geometry-linestring.feature

@@ -16,14 +16,16 @@ Feature: Creating linestring features from way
                 { column = 'sgeom', type = 'linestring', projection = 4326 },
                 { column = 'mgeom', type = 'multilinestring', projection = 4326 },
                 { column = 'xgeom', type = 'multilinestring', projection = 4326 },
+                { column = 'npoints', type = 'int' },
             })
 
             function osm2pgsql.process_way(object)
                 if object.tags.highway == 'motorway' then
                     lines:insert({
                         sgeom = object:as_linestring(),
                         mgeom = object:as_multilinestring(),
-                        xgeom = object:as_linestring()
+                        xgeom = object:as_linestring(),
+                        npoints = object:as_linestring():n_points(),
                     })
                 end
             end
@@ -32,9 +34,9 @@ Feature: Creating linestring features from way
         When running osm2pgsql flex
 
         Then table osm2pgsql_test_lines contains exactly
-            | way_id | sgeom!geo | mgeom!geo   | xgeom!geo   |
-            | 20     | 1, 2, 3   | [ 1, 2, 3 ] | [ 1, 2, 3 ] |
-            | 21     | 4, 5      | [ 4, 5 ]    | [ 4, 5 ]    |
+            | way_id | sgeom!geo | mgeom!geo   | xgeom!geo   | npoints |
+            | 20     | 1, 2, 3   | [ 1, 2, 3 ] | [ 1, 2, 3 ] | 3       |
+            | 21     | 4, 5      | [ 4, 5 ]    | [ 4, 5 ]    | 2       |
 
     Scenario:
         Given the grid

tests/test-geom-collections.cpp

@@ -24,6 +24,7 @@ TEST_CASE("geometry collection with point", "[NoDB]")
     c.add_geometry(geom::geometry_t{geom::point_t{1, 1}});
 
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
+    REQUIRE(geom.n_points() == 1);
     REQUIRE(dimension(geom) == 0);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
@@ -46,6 +47,7 @@ TEST_CASE("geometry collection with multipoint", "[NoDB]")
     c.add_geometry(std::move(mpgeom));
 
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
+    REQUIRE(geom.n_points() == 4);
     REQUIRE(dimension(geom) == 0);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
@@ -62,6 +64,7 @@ TEST_CASE("geometry collection with several geometries", "[NoDB]")
     c.add_geometry(geom::geometry_t{geom::point_t{2, 2}});
 
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
+    REQUIRE(geom.n_points() == 4);
     REQUIRE(dimension(geom) == 1);
     REQUIRE(num_geometries(geom) == 3);
     REQUIRE(area(geom) == Approx(0.0));
@@ -83,6 +86,7 @@ TEST_CASE("geometry collection with polygon", "[NoDB]")
         geom::polygon_t{geom::ring_t{{1, 1}, {1, 2}, {2, 2}, {2, 1}, {1, 1}}}});
 
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
+    REQUIRE(geom.n_points() == 6);
     REQUIRE(num_geometries(geom) == 2);
     REQUIRE(area(geom) == Approx(1.0));
     REQUIRE(length(geom) == Approx(0.0));
@@ -100,6 +104,7 @@ TEST_CASE("create_collection from OSM data", "[NoDB]")
     auto const geom = geom::create_collection(buffer.buffer());
 
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
+    REQUIRE(geom.n_points() == 8);
     REQUIRE(dimension(geom) == 1);
     REQUIRE(num_geometries(geom) == 3);
 

tests/test-geom-linestrings.cpp

@@ -52,6 +52,7 @@ TEST_CASE("line geometry", "[NoDB]")
 {
     geom::geometry_t const geom{geom::linestring_t{{1, 1}, {2, 2}}};
 
+    REQUIRE(geom.n_points() == 2);
     REQUIRE(dimension(geom) == 1);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));

tests/test-geom-multilinestrings.cpp

@@ -32,6 +32,7 @@ TEST_CASE("create_multilinestring with single line", "[NoDB]")
 
     REQUIRE(geom.is_multilinestring());
     REQUIRE(geometry_type(geom) == "MULTILINESTRING");
+    REQUIRE(geom.n_points() == 2);
     REQUIRE(dimension(geom) == 1);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
@@ -59,6 +60,7 @@ TEST_CASE("create_multilinestring with single line and no force_multi",
 
     REQUIRE(geom.is_linestring());
     REQUIRE(geometry_type(geom) == "LINESTRING");
+    REQUIRE(geom.n_points() == 2);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
     REQUIRE(spherical_area(geom) == Approx(0.0));
@@ -132,6 +134,7 @@ TEST_CASE("create_multilinestring from two non-joined lines", "[NoDB]")
         geom::line_merge(geom::create_multilinestring(buffer.buffer()));
 
     REQUIRE(geom.is_multilinestring());
+    REQUIRE(geom.n_points() == 4);
     REQUIRE(dimension(geom) == 1);
     auto const &ml = geom.get<geom::multilinestring_t>();
     REQUIRE(ml.num_geometries() == 2);
@@ -152,6 +155,7 @@ TEST_CASE("create_multilinestring from two lines end to end", "[NoDB]")
 
     REQUIRE(geom.is_multilinestring());
     auto const &ml = geom.get<geom::multilinestring_t>();
+    REQUIRE(ml.n_points() == 3);
     REQUIRE(ml.num_geometries() == 1);
     REQUIRE(ml[0] == expected);
 }
@@ -292,6 +296,7 @@ TEST_CASE("create_multilinestring from Y shape", "[NoDB]")
     REQUIRE(geom.is_multilinestring());
     auto const &ml = geom.get<geom::multilinestring_t>();
     REQUIRE(ml.num_geometries() == 2);
+    REQUIRE(ml.n_points() == 5);
     REQUIRE(ml[0] == expected[0]);
     REQUIRE(ml[1] == expected[1]);
 }

tests/test-geom-multipoints.cpp

@@ -29,6 +29,7 @@ TEST_CASE("multipoint_t with a single point", "[NoDB]")
 
     REQUIRE(geom.is_multipoint());
     REQUIRE(geometry_type(geom) == "MULTIPOINT");
+    REQUIRE(geom.n_points() == 1);
     REQUIRE(dimension(geom) == 0);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
@@ -54,6 +55,7 @@ TEST_CASE("multipoint_t with several points", "[NoDB]")
 
     REQUIRE(geom.is_multipoint());
     REQUIRE(geometry_type(geom) == "MULTIPOINT");
+    REQUIRE(geom.n_points() == 3);
     REQUIRE(num_geometries(geom) == 3);
     REQUIRE(area(geom) == Approx(0.0));
     REQUIRE(spherical_area(geom) == Approx(0.0));
@@ -85,6 +87,7 @@ TEST_CASE("create_multipoint from OSM data", "[NoDB]")
 
     REQUIRE(geometry_type(geom) == "MULTIPOINT");
     REQUIRE(dimension(geom) == 0);
+    REQUIRE(geom.n_points() == 4);
     REQUIRE(num_geometries(geom) == 4);
 
     auto const &c = geom.get<geom::multipoint_t>();

tests/test-geom-multipolygons.cpp

@@ -26,6 +26,7 @@ TEST_CASE("multipolygon geometry with single outer, no inner", "[NoDB]")
         geom::polygon_t{geom::ring_t{{0, 0}, {0, 1}, {1, 1}, {1, 0}, {0, 0}}});
 
     REQUIRE(geometry_type(geom) == "MULTIPOLYGON");
+    REQUIRE(geom.n_points() == 5);
     REQUIRE(dimension(geom) == 2);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(1.0));
@@ -56,6 +57,7 @@ TEST_CASE("multipolygon geometry with two polygons", "[NoDB]")
     mp.add_geometry(std::move(polygon));
 
     REQUIRE(geometry_type(geom) == "MULTIPOLYGON");
+    REQUIRE(geom.n_points() == 15);
     REQUIRE(dimension(geom) == 2);
     REQUIRE(num_geometries(geom) == 2);
     REQUIRE(area(geom) == Approx(9.0));
@@ -76,6 +78,7 @@ TEST_CASE("create_multipolygon creates simple polygon from OSM data", "[NoDB]")
 
     REQUIRE(geom.is_polygon());
     REQUIRE(geometry_type(geom) == "POLYGON");
+    REQUIRE(geom.n_points() == 5);
     REQUIRE(dimension(geom) == 2);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(1.0));
@@ -99,6 +102,7 @@ TEST_CASE("create_multipolygon from OSM data", "[NoDB]")
         geom::create_multipolygon(relation, buffer.buffer(), &area_buffer);
 
     REQUIRE(geom.is_multipolygon());
+    REQUIRE(geom.n_points() == 9);
     REQUIRE(geometry_type(geom) == "MULTIPOLYGON");
     REQUIRE(num_geometries(geom) == 2);
     REQUIRE(area(geom) == Approx(51.0));

tests/test-geom-null.cpp

@@ -18,6 +18,7 @@ TEST_CASE("null geometry", "[NoDB]")
 {
     geom::geometry_t const geom{};
 
+    REQUIRE(geom.n_points() == 0);
     REQUIRE(dimension(geom) == 0);
     REQUIRE(num_geometries(geom) == 0);
     REQUIRE(area(geom) == Approx(0.0));

tests/test-geom-points.cpp

@@ -65,6 +65,7 @@ TEST_CASE("create_point from OSM data", "[NoDB]")
 
     REQUIRE(geom.is_point());
     REQUIRE(geometry_type(geom) == "POINT");
+    REQUIRE(geom.n_points() == 1);
     REQUIRE(dimension(geom) == 0);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));

tests/test-geom-polygons.cpp

@@ -22,6 +22,7 @@ TEST_CASE("polygon geometry without inner", "[NoDB]")
     geom::geometry_t const geom{
         geom::polygon_t{geom::ring_t{{0, 0}, {0, 1}, {1, 1}, {1, 0}, {0, 0}}}};
 
+    REQUIRE(geom.n_points() == 5);
     REQUIRE(dimension(geom) == 2);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(1.0));
@@ -38,6 +39,7 @@ TEST_CASE("polygon geometry without inner (reverse)", "[NoDB]")
     geom::geometry_t const geom{
         geom::polygon_t{geom::ring_t{{0, 0}, {1, 0}, {1, 1}, {0, 1}, {0, 0}}}};
 
+    REQUIRE(geom.n_points() == 5);
     REQUIRE(dimension(geom) == 2);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(1.0));
@@ -62,6 +64,7 @@ TEST_CASE("geom::polygon_t", "[NoDB]")
     REQUIRE(polygon.inners().size() == 1);
 
     geom::geometry_t const geom{std::move(polygon)};
+    REQUIRE(geom.n_points() == 10);
     REQUIRE(dimension(geom) == 2);
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(8.0));