Repo created

TMessagesProj/jni/voip/webrtc/base/tuple.h

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+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Use std::tuple as tuple type. This file contains helper functions for
+// working with std::tuples.
+// The functions DispatchToMethod and DispatchToFunction take a function pointer
+// or instance and method pointer, and unpack a tuple into arguments to the
+// call.
+//
+// Example usage:
+//   // These two methods of creating a Tuple are identical.
+//   std::tuple<int, const char*> tuple_a(1, "wee");
+//   std::tuple<int, const char*> tuple_b = std::make_tuple(1, "wee");
+//
+//   void SomeFunc(int a, const char* b) { }
+//   DispatchToFunction(&SomeFunc, tuple_a);  // SomeFunc(1, "wee")
+//   DispatchToFunction(
+//       &SomeFunc, std::make_tuple(10, "foo"));    // SomeFunc(10, "foo")
+//
+//   struct { void SomeMeth(int a, int b, int c) { } } foo;
+//   DispatchToMethod(&foo, &Foo::SomeMeth, std::make_tuple(1, 2, 3));
+//   // foo->SomeMeth(1, 2, 3);
+
+#ifndef BASE_TUPLE_H_
+#define BASE_TUPLE_H_
+
+#include <stddef.h>
+#include <tuple>
+#include <utility>
+
+#include "build/build_config.h"
+
+namespace base {
+
+// Dispatchers ----------------------------------------------------------------
+//
+// Helper functions that call the given method on an object, with the unpacked
+// tuple arguments.  Notice that they all have the same number of arguments,
+// so you need only write:
+//   DispatchToMethod(object, &Object::method, args);
+// This is very useful for templated dispatchers, since they don't need to know
+// what type |args| is.
+
+// Non-Static Dispatchers with no out params.
+
+template <typename ObjT, typename Method, typename Tuple, size_t... Ns>
+inline void DispatchToMethodImpl(const ObjT& obj,
+                                 Method method,
+                                 Tuple&& args,
+                                 std::index_sequence<Ns...>) {
+  (obj->*method)(std::get<Ns>(std::forward<Tuple>(args))...);
+}
+
+template <typename ObjT, typename Method, typename Tuple>
+inline void DispatchToMethod(const ObjT& obj,
+                             Method method,
+                             Tuple&& args) {
+  constexpr size_t size = std::tuple_size<std::decay_t<Tuple>>::value;
+  DispatchToMethodImpl(obj, method, std::forward<Tuple>(args),
+                       std::make_index_sequence<size>());
+}
+
+// Static Dispatchers with no out params.
+
+template <typename Function, typename Tuple, size_t... Ns>
+inline void DispatchToFunctionImpl(Function function,
+                                   Tuple&& args,
+                                   std::index_sequence<Ns...>) {
+  (*function)(std::get<Ns>(std::forward<Tuple>(args))...);
+}
+
+template <typename Function, typename Tuple>
+inline void DispatchToFunction(Function function, Tuple&& args) {
+  constexpr size_t size = std::tuple_size<std::decay_t<Tuple>>::value;
+  DispatchToFunctionImpl(function, std::forward<Tuple>(args),
+                         std::make_index_sequence<size>());
+}
+
+// Dispatchers with out parameters.
+
+template <typename ObjT,
+          typename Method,
+          typename InTuple,
+          typename OutTuple,
+          size_t... InNs,
+          size_t... OutNs>
+inline void DispatchToMethodImpl(const ObjT& obj,
+                                 Method method,
+                                 InTuple&& in,
+                                 OutTuple* out,
+                                 std::index_sequence<InNs...>,
+                                 std::index_sequence<OutNs...>) {
+  (obj->*method)(std::get<InNs>(std::forward<InTuple>(in))...,
+                 &std::get<OutNs>(*out)...);
+}
+
+template <typename ObjT, typename Method, typename InTuple, typename OutTuple>
+inline void DispatchToMethod(const ObjT& obj,
+                             Method method,
+                             InTuple&& in,
+                             OutTuple* out) {
+  constexpr size_t in_size = std::tuple_size<std::decay_t<InTuple>>::value;
+  constexpr size_t out_size = std::tuple_size<OutTuple>::value;
+  DispatchToMethodImpl(obj, method, std::forward<InTuple>(in), out,
+                       std::make_index_sequence<in_size>(),
+                       std::make_index_sequence<out_size>());
+}
+
+}  // namespace base
+
+#endif  // BASE_TUPLE_H_