update ceph source to reef 18.1.2

[ceph.git] / ceph / src / jaegertracing / opentelemetry-cpp / api / include / opentelemetry / nostd / detail / type_pack_element.h

diff --git a/ceph/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/nostd/detail/type_pack_element.h b/ceph/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/nostd/detail/type_pack_element.h
new file mode 100644 (file)
index 0000000..0c522dd
--- /dev/null
+++ b/ceph/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/nostd/detail/type_pack_element.h
@@ -0,0 +1,50 @@
+#pragma once
+
+#include <cstddef>
+#include <type_traits>
+
+#include "opentelemetry/nostd/utility.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace nostd
+{
+namespace detail
+{
+template <std::size_t N>
+using size_constant = std::integral_constant<std::size_t, N>;
+
+template <std::size_t I, typename T>
+struct indexed_type : size_constant<I>
+{
+  using type = T;
+};
+
+template <std::size_t I, typename... Ts>
+struct type_pack_element_impl
+{
+private:
+  template <typename>
+  struct set;
+
+  template <std::size_t... Is>
+  struct set<index_sequence<Is...>> : indexed_type<Is, Ts>...
+  {};
+
+  template <typename T>
+  inline static std::enable_if<true, T> impl(indexed_type<I, T>);
+
+  inline static std::enable_if<false> impl(...);
+
+public:
+  using type = decltype(impl(set<index_sequence_for<Ts...>>{}));
+};
+
+template <std::size_t I, typename... Ts>
+using type_pack_element = typename type_pack_element_impl<I, Ts...>::type;
+
+template <std::size_t I, typename... Ts>
+using type_pack_element_t = typename type_pack_element<I, Ts...>::type;
+}  // namespace detail
+}  // namespace nostd
+OPENTELEMETRY_END_NAMESPACE