hash: Add support for tuples
There is now builtin support for stdplus::hash<> and
stdplus::hashMulti(...) hashing std::tuple containers.
Change-Id: I0e0983c04d54302f00c811e5de0d949accee03d7
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/include/meson.build b/include/meson.build
index 358bc32..fc304f3 100644
--- a/include/meson.build
+++ b/include/meson.build
@@ -7,6 +7,7 @@
'stdplus/handle/copyable.hpp',
'stdplus/handle/managed.hpp',
'stdplus/hash.hpp',
+ 'stdplus/hash/tuple.hpp',
'stdplus/pinned.hpp',
'stdplus/raw.hpp',
'stdplus/signal.hpp',
diff --git a/include/stdplus/hash.hpp b/include/stdplus/hash.hpp
index 44cc6a6..f3aa8e6 100644
--- a/include/stdplus/hash.hpp
+++ b/include/stdplus/hash.hpp
@@ -1,5 +1,6 @@
#pragma once
#include <cstddef>
+#include <tuple>
#include <utility>
namespace std
@@ -65,4 +66,14 @@
struct hash : std::hash<Key>
{};
+template <typename... Ts>
+struct hash<std::tuple<Ts...>>
+{
+ constexpr std::size_t operator()(const std::tuple<Ts...>& ts) noexcept(
+ noexcept(hashMulti(std::declval<Ts>()...)))
+ {
+ return std::apply(hashMulti<Ts...>, ts);
+ }
+};
+
} // namespace stdplus
diff --git a/include/stdplus/hash/tuple.hpp b/include/stdplus/hash/tuple.hpp
new file mode 100644
index 0000000..be7a45e
--- /dev/null
+++ b/include/stdplus/hash/tuple.hpp
@@ -0,0 +1,14 @@
+#pragma once
+#include <stdplus/hash.hpp>
+
+#include <tuple>
+
+template <typename... Ts>
+struct std::hash<std::tuple<Ts...>>
+{
+ constexpr auto operator()(const std::tuple<Ts...>& ts) const noexcept(
+ noexcept(stdplus::hashMulti(std::declval<std::tuple<Ts...>>())))
+ {
+ return stdplus::hashMulti(ts);
+ }
+};