.. _program_listing_file__tmp_ws_src_message_filters_include_message_filters_message_traits.h:

Program Listing for File message_traits.h
=========================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_message_filters_include_message_filters_message_traits.h>` (``/tmp/ws/src/message_filters/include/message_filters/message_traits.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   /*
    * Copyright (C) 2009, Willow Garage, Inc.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions are met:
    *   * Redistributions of source code must retain the above copyright notice,
    *     this list of conditions and the following disclaimer.
    *   * Redistributions in binary form must reproduce the above copyright
    *     notice, this list of conditions and the following disclaimer in the
    *     documentation and/or other materials provided with the distribution.
    *   * Neither the names of Willow Garage, Inc. nor the names of its
    *     contributors may be used to endorse or promote products derived from
    *     this software without specific prior written permission.
    *
    * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
    * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    * POSSIBILITY OF SUCH DAMAGE.
    */
   
   // File imported from
   // https://github.com/ros/roscpp_core/blob/38b9663/roscpp_traits/include/ros/message_traits.h
   
   #ifndef MESSAGE_FILTERS__MESSAGE_TRAITS_H_
   #define MESSAGE_FILTERS__MESSAGE_TRAITS_H_
   
   #include <type_traits>
   
   #include <rclcpp/rclcpp.hpp>
   #include <std_msgs/msg/header.hpp>
   
   namespace message_filters
   {
   namespace message_traits
   {
   
   template<typename M, typename = void>
   struct HasHeader : public std::false_type {};
   
   template <typename M>
   struct HasHeader<M, typename std::enable_if<std::is_same<std_msgs::msg::Header,
     decltype(M().header)>::value>::type>: public std::true_type {};
   
   template<typename M, typename Enable = void>
   struct FrameId
   {
     static std::string* pointer(M& m) { (void)m; return nullptr; }
     static std::string const* pointer(const M& m) { (void)m; return nullptr; }
   };
   template<typename M>
   struct FrameId<M, typename std::enable_if<HasHeader<M>::value>::type >
   {
     static std::string* pointer(M& m) { return &m.header.frame_id; }
     static std::string const* pointer(const M& m) { return &m.header.frame_id; }
     static std::string value(const M& m) { return m.header.frame_id; }
   };
   
   template<typename M, typename Enable = void>
   struct TimeStamp
   {
     static rclcpp::Time value(const M& m) {
       (void)m;
       return rclcpp::Time();
     }
   };
   
   template<typename M>
   struct TimeStamp<M, typename std::enable_if<HasHeader<M>::value>::type >
   {
     static rclcpp::Time value(const M& m) {
       return rclcpp::Time(m.header.stamp, RCL_ROS_TIME);
     }
   };
   
   }  // namespace message_traits
   }  // namespace message_filters
   
   #endif  // MESSAGE_FILTERS__MESSAGE_TRAITS_H_