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Add std::hash specialization

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This commit is contained in:
Andrzej Krzemienski
2022-05-21 01:13:10 +02:00
parent 6117d08d79
commit 52abe4842e
4 changed files with 115 additions and 0 deletions
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49
include/boost/optional/detail/optional_hash.hpp Normal file
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// Copyright (C) 2022 Andrzej Krzemienski.
//
// Use, modification, and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/optional for documentation.
//
// You are welcome to contact the author at:
// akrzemi1@gmail.com
#ifndef BOOST_OPTIONAL_DETAIL_OPTIONAL_HASH_AJK_20MAY2022_HPP
#define BOOST_OPTIONAL_DETAIL_OPTIONAL_HASH_AJK_20MAY2022_HPP
#include <boost/optional/optional_fwd.hpp>
#include <boost/config.hpp>
#if !defined(BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
#include <functional>
namespace std
{
template <typename T>
struct hash<boost::optional<T> >
{
typedef typename hash<T>::result_type result_type;
typedef boost::optional<T> argument_type;
BOOST_CONSTEXPR result_type operator()(const argument_type& arg) const {
return arg ? std::hash<T>()(*arg) : result_type();
}
};
template <typename T>
struct hash<boost::optional<T&> >
{
typedef typename hash<T>::result_type result_type;
typedef boost::optional<T&> argument_type;
BOOST_CONSTEXPR result_type operator()(const argument_type& arg) const {
return arg ? std::hash<T>()(*arg) : result_type();
}
};
}
#endif // !defined(BOOST_OPTIONAL_CONFIG_DO_NOT_SPECIALIZE_STD_HASH) && !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
#endif // header guard

1
include/boost/optional/optional.hpp
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#include <boost/optional/detail/optional_config.hpp>
#include <boost/optional/detail/optional_factory_support.hpp>
#include <boost/optional/detail/optional_aligned_storage.hpp>
#include <boost/optional/detail/optional_hash.hpp>
namespace boost { namespace optional_detail {