1 files changed, 22 insertions, 0 deletions
diff --git a/src/util/hash_impl.hpp b/src/util/hash_impl.hpp
new file mode 100644
index 0000000..146cfa0
--- /dev/null
+++ b/src/util/hash_impl.hpp
@@ -0,0 +1,22 @@
+#pragma once
+
+#include "hash.hpp"
+
+#include <cstdint>
+#include <functional>
+
+/**
+ * Combines the hash 'seed' with the hash of 'value'.
+ *
+ * @param seed A hash that will be mutated
+ * @param value A hashable value
+ */
+template <typename Value>
+void hash_combine(std::size_t &seed, const Value &value) noexcept
+{
+	constexpr uint32_t shift_left = 6;
+	constexpr uint32_t shift_right = 2;
+
+	seed ^= std::hash<Value>()(value) + GOLDEN_RATIO + (seed << shift_left) +
+			(seed >> shift_right);
+}