Add spaceship for QuantityPoint

aurora-opensource · Dec 10, 2024 · 89c0a5c · 89c0a5c
1 parent 25090bf
commit 89c0a5c
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Showing 3 changed files with 19 additions and 0 deletions.
diff --git a/au/BUILD.bazel b/au/BUILD.bazel
@@ -72,6 +72,7 @@ cc_test(
     tags = ["manual"],
     deps = [
         ":quantity",
+        ":quantity_point",
         ":testing",
         ":units",
         "@com_google_googletest//:gtest_main",

diff --git a/au/code/au/cpp20_test.cc b/au/code/au/cpp20_test.cc
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include "au/quantity.hh"
+#include "au/quantity_point.hh"
 #include "au/testing.hh"
 #include "au/units/meters.hh"
 
@@ -26,6 +27,14 @@ struct Foo {
     QuantityD<Meters> thickness;
 };
 
+struct FooPt {
+    auto operator<=>(const FooPt &) const = default;
+
+    QuantityPointD<Meters> position;
+};
+
 TEST(Quantity, SupportsSpaceship) { EXPECT_LT(Foo{5 * m}, Foo{6 * m}); }
 
+TEST(QuantityPoint, SupportsSpaceship) { EXPECT_LT(FooPt{meters_pt(5)}, FooPt{meters_pt(6)}); }
+
 }  // namespace au
diff --git a/au/code/au/quantity_point.hh b/au/code/au/quantity_point.hh
@@ -370,6 +370,15 @@ constexpr auto operator-(QuantityPoint<U1, R1> p1, QuantityPoint<U2, R2> p2) {
     return detail::using_common_point_unit(p1, p2, detail::minus);
 }
 
+// Spaceship operator provides C++20 compatibility.
+#if __cplusplus >= 202002L
+template <typename U1, typename R1, typename U2, typename R2>
+constexpr auto operator<=>(const QuantityPoint<U1, R1> &lhs, const QuantityPoint<U2, R2> &rhs) {
+    using U = CommonPointUnitT<U1, U2>;
+    return lhs.in(U{}) <=> rhs.in(U{});
+}
+#endif
+
 namespace detail {
 
 template <typename TargetRep, typename U, typename R>