Specialize std::hash for RecordRef

alpaka-group · Aug 9, 2023 · 550a685 · 550a685
1 parent a3de119
commit 550a685
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diff --git a/include/llama/RecordRef.hpp b/include/llama/RecordRef.hpp
@@ -9,6 +9,7 @@
 #include "View.hpp"
 #include "macros.hpp"
 
+#include <boost/functional/hash.hpp>
 #include <iosfwd>
 #include <type_traits>
 
@@ -1011,6 +1012,19 @@ struct std::tuple_element<I, const llama::RecordRef<View, BoundRecordCoord, OwnV
     using type = decltype(std::declval<const llama::RecordRef<View, BoundRecordCoord, OwnView>>().template get<I>());
 };
 
+template<typename View, typename BoundRecordCoord, bool OwnView>
+struct std::hash<llama::RecordRef<View, BoundRecordCoord, OwnView>>
+{
+    auto operator()(const llama::RecordRef<View, BoundRecordCoord, OwnView>& rr) const -> std::size_t
+    {
+        std::size_t acc = 0;
+        llama::forEachLeaf(
+            rr,
+            [&](auto&& ref) LLAMA_LAMBDA_INLINE { boost::hash_combine(acc, llama::decayCopy(ref)); });
+        return acc;
+    }
+};
+
 #if CAN_USE_RANGES
 template<
     typename ViewA,

diff --git a/tests/recordref.cpp b/tests/recordref.cpp
@@ -1108,6 +1108,20 @@ TEST_CASE("RecordRef.operator<<")
     CHECK(ss.str() == expected);
 }
 
+TEST_CASE("RecordRef.hash")
+{
+    llama::One<Vec3I> v;
+    llama::forEachLeaf(v, [i = 0](auto& ref) mutable { ref = ++i; });
+
+    std::size_t reference = 0;
+    boost::hash_combine(reference, v(tag::X{}));
+    boost::hash_combine(reference, v(tag::Y{}));
+    boost::hash_combine(reference, v(tag::Z{}));
+
+    CHECK(std::hash<decltype(v)>{}(v) == reference);
+    CHECK(std::hash<decltype(v())>{}(v()) == reference);
+}
+
 TEST_CASE("RecordRef.swap")
 {
     llama::One<Vec3I> p1{1};