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
   7 // Antony Polukhin
   8 //
   9 // Distributed under the Boost Software License, Version 1.0. (See
  10 // accompanying file LICENSE_1_0.txt or copy at
  11 // http://www.boost.org/LICENSE_1_0.txt)
  12
  13
  14 #ifndef BOOST_HASH_VARIANT_FUNCTION_HPP
  15 #define BOOST_HASH_VARIANT_FUNCTION_HPP
  16
  17 #if defined(_MSC_VER)
  18 # pragma once
  19 #endif
  20
  21 #include <boost/variant/variant_fwd.hpp>
  22 #include <boost/variant/static_visitor.hpp>
  23 #include <boost/variant/apply_visitor.hpp>
  24 #include <boost/functional/hash_fwd.hpp>
  25
  26 namespace boost {
  27
  28     namespace detail { namespace variant {
  29         struct variant_hasher: public boost::static_visitor<std::size_t> {
  30             template <class T>
  31             std::size_t operator()(T const& val) const {
  32                 boost::hash<T> hasher;
  33                 return hasher(val);
  34             }
  35         };
  36     }}
  37
  38     template < BOOST_VARIANT_ENUM_PARAMS(typename T) >
  39     std::size_t hash_value(variant< BOOST_VARIANT_ENUM_PARAMS(T) > const& val) {
  40         std::size_t seed = boost::apply_visitor(detail::variant::variant_hasher(), val);
  41         hash_combine(seed, val.which());
  42         return seed;
  43     }
  44 }
  45
  46 #endif
  47