ceph/src/boost/boost/variant/detail/std_hash.hpp

   1 //-----------------------------------------------------------------------------
   2 // boost variant/detail/std_hash.hpp header file
   3 // See http://www.boost.org for updates, documentation, and revision history.
   4 //-----------------------------------------------------------------------------
   5 //
   6 // Copyright (c) 2018-2019 Antony Polukhin
   7 //
   8 // Distributed under the Boost Software License, Version 1.0. (See
   9 // accompanying file LICENSE_1_0.txt or copy at
  10 // http://www.boost.org/LICENSE_1_0.txt)
  11
  12
  13 #ifndef BOOST_VARIANT_DETAIL_STD_HASH_HPP
  14 #define BOOST_VARIANT_DETAIL_STD_HASH_HPP
  15
  16 #include <boost/config.hpp>
  17 #ifdef BOOST_HAS_PRAGMA_ONCE
  18 # pragma once
  19 #endif
  20
  21 #include <boost/variant/variant_fwd.hpp>
  22 #include <boost/variant/detail/hash_variant.hpp>
  23
  24 ///////////////////////////////////////////////////////////////////////////////
  25 // macro BOOST_VARIANT_DO_NOT_SPECIALIZE_STD_HASH
  26 //
  27 // Define this macro if you do not with to have a std::hash specialization for
  28 // boost::variant.
  29
  30 #if !defined(BOOST_VARIANT_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
  31
  32 #include <functional> // for std::hash
  33
  34 namespace std {
  35     template < BOOST_VARIANT_ENUM_PARAMS(typename T) >
  36     struct hash<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) > > {
  37         std::size_t operator()(const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& val) const {
  38             return ::boost::hash_value(val);
  39         }
  40     };
  41 }
  42
  43 #endif // #if !defined(BOOST_VARIANT_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
  44
  45 #endif // BOOST_VARIANT_DETAIL_STD_HASH_HPP
  46