modules/core/include/dpl/bind.h

   1 /*
   2  * Copyright (c) 2013 Samsung Electronics Co., Ltd All Rights Reserved
   3  *
   4  *    Licensed under the Apache License, Version 2.0 (the "License");
   5  *    you may not use this file except in compliance with the License.
   6  *    You may obtain a copy of the License at
   7  *
   8  *        http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  *    Unless required by applicable law or agreed to in writing, software
  11  *    distributed under the License is distributed on an "AS IS" BASIS,
  12  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  *    See the License for the specific language governing permissions and
  14  *    limitations under the License.
  15  */
  16 /*
  17  * @file        bind.h
  18  * @author      Zbigniew Kostrzewa (z.kostrzewa@samsung.com)
  19  * @version     1.0
  20  * @brief       This file is the header file of bind
  21  */
  22
  23 /*
  24  * Remarks:
  25  * - Current implementation supports binding member functions (methods) only.
  26  * - Currently up to 8 std::placeholders are supported.
  27  * - Bound delegates are of type std::function<...>. This implies that
  28  *   passing arguments at bind-time is not supported (arguments MAY ONLY be
  29  *   passed at call-time).
  30  *
  31  * Usage:
  32  * - For usage see tests/core/test_bind.cpp. In general, usage comes down to:
  33  *   std::function<ResultType(Args...)> delegate =
  34  *      DPL::Bind(&ObjectType::MethodName, &object);
  35  */
  36
  37 #ifndef DPL_BIND_H_
  38 #define DPL_BIND_H_
  39
  40 #include <functional>
  41
  42 #include <boost/preprocessor/cat.hpp>
  43 #include <boost/preprocessor/arithmetic/add.hpp>
  44 #include <boost/preprocessor/repetition/repeat.hpp>
  45
  46 namespace DPL {
  47 namespace detail {
  48 template<size_t>
  49 struct PlaceholdersBindHelper;
  50
  51 #define DPL_PLACEHOLDERS_LIST_(z, n, t) ,BOOST_PP_CAT(std::placeholders::_,    \
  52                                                       BOOST_PP_ADD(n, 1))
  53 #define DPL_PLACEHOLDERS_(count) BOOST_PP_REPEAT(count,                        \
  54                                                  DPL_PLACEHOLDERS_LIST_,       \
  55                                                  count)
  56 #define DPL_PLACEHOLDERS_BIND_HELPER_(count)                                   \
  57 template<>                                                                     \
  58 struct PlaceholdersBindHelper<count>                                           \
  59 {                                                                              \
  60     template<typename Result, typename Type, typename ...Args>                 \
  61     static std::function<Result(Args...)>                                      \
  62     bind(Result(Type::*method)(Args...), Type* object) {                       \
  63         return std::bind(method, object DPL_PLACEHOLDERS_(count));             \
  64     }                                                                          \
  65 }
  66
  67 DPL_PLACEHOLDERS_BIND_HELPER_(0);
  68 DPL_PLACEHOLDERS_BIND_HELPER_(1);
  69 DPL_PLACEHOLDERS_BIND_HELPER_(2);
  70 DPL_PLACEHOLDERS_BIND_HELPER_(3);
  71 DPL_PLACEHOLDERS_BIND_HELPER_(4);
  72 DPL_PLACEHOLDERS_BIND_HELPER_(5);
  73 DPL_PLACEHOLDERS_BIND_HELPER_(6);
  74 DPL_PLACEHOLDERS_BIND_HELPER_(7);
  75 DPL_PLACEHOLDERS_BIND_HELPER_(8);
  76 }
  77
  78 template<typename Result, typename Type, typename ...Args>
  79 std::function<Result(Args...)> Bind(Result(Type::*method)(Args...),
  80                                     Type* object)
  81 {
  82     return detail::PlaceholdersBindHelper<sizeof...(Args)>::bind(method,
  83                                                                  object);
  84 }
  85 }
  86
  87 #endif // DPL_BIND_H_