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

   1 //-----------------------------------------------------------------------------
   2 // boost variant/detail/hash_variant.hpp header file
   3 // See http://www.boost.org for updates, documentation, and revision history.
   4 //-----------------------------------------------------------------------------
   5 //
   6 // Copyright (c) 2011-2019 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_HASH_VARIANT_FUNCTION_HPP
  14 #define BOOST_HASH_VARIANT_FUNCTION_HPP
  15
  16 #if defined(_MSC_VER)
  17 # pragma once
  18 #endif
  19
  20 #include <boost/variant/variant_fwd.hpp>
  21 #include <boost/variant/static_visitor.hpp>
  22 #include <boost/variant/apply_visitor.hpp>
  23 #include <boost/functional/hash_fwd.hpp>
  24
  25 namespace boost {
  26
  27     namespace detail { namespace variant {
  28         struct variant_hasher: public boost::static_visitor<std::size_t> {
  29             template <class T>
  30             std::size_t operator()(T const& val) const {
  31                 boost::hash<T> hasher;
  32                 return hasher(val);
  33             }
  34         };
  35     }}
  36
  37     template < BOOST_VARIANT_ENUM_PARAMS(typename T) >
  38     std::size_t hash_value(variant< BOOST_VARIANT_ENUM_PARAMS(T) > const& val) {
  39         std::size_t seed = boost::apply_visitor(detail::variant::variant_hasher(), val);
  40         hash_combine(seed, val.which());
  41         return seed;
  42     }
  43 }
  44
  45 #endif
  46