danicoin/src/serialization/variant.h

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// Copyright (c) 2014-2017, The Monero Project
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//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. 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.
//
// 3. Neither the name of the copyright holder 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 HOLDER 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.
//
// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
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/*! \file variant.h
*
* \brief for dealing with variants
*
* \detailed Variant: OOP Union
*/
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#pragma once
#include <boost/variant/variant.hpp>
#include <boost/variant/apply_visitor.hpp>
#include <boost/variant/static_visitor.hpp>
#include <boost/mpl/empty.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/front.hpp>
#include <boost/mpl/pop_front.hpp>
#include "serialization.h"
/*! \struct variant_serialization_triats
*
* \brief used internally to contain a variant's traits/possible types
*
* \detailed see the macro VARIANT_TAG in serialization.h:140
*/
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template <class Archive, class T>
struct variant_serialization_traits
{
};
/*! \struct variant_reader
*
* \brief reads a variant
*/
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template <class Archive, class Variant, class TBegin, class TEnd>
struct variant_reader
{
typedef typename Archive::variant_tag_type variant_tag_type;
typedef typename boost::mpl::next<TBegin>::type TNext;
typedef typename boost::mpl::deref<TBegin>::type current_type;
// A tail recursive inline function.... okay...
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static inline bool read(Archive &ar, Variant &v, variant_tag_type t)
{
if(variant_serialization_traits<Archive, current_type>::get_tag() == t) {
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current_type x;
if(!::do_serialize(ar, x))
{
ar.stream().setstate(std::ios::failbit);
return false;
}
v = x;
} else {
// Tail recursive.... but no mutation is going on. Why?
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return variant_reader<Archive, Variant, TNext, TEnd>::read(ar, v, t);
}
return true;
}
};
// This one just fails when you call it.... okay
// So the TEnd parameter must be specified/differnt from TBegin
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template <class Archive, class Variant, class TBegin>
struct variant_reader<Archive, Variant, TBegin, TBegin>
{
typedef typename Archive::variant_tag_type variant_tag_type;
static inline bool read(Archive &ar, Variant &v, variant_tag_type t)
{
ar.stream().setstate(std::ios::failbit);
return false;
}
};
template <template <bool> class Archive, BOOST_VARIANT_ENUM_PARAMS(typename T)>
struct serializer<Archive<false>, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
{
typedef boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> variant_type;
typedef typename Archive<false>::variant_tag_type variant_tag_type;
typedef typename variant_type::types types;
static bool serialize(Archive<false> &ar, variant_type &v) {
variant_tag_type t;
ar.begin_variant();
ar.read_variant_tag(t);
if(!variant_reader<Archive<false>, variant_type,
typename boost::mpl::begin<types>::type,
typename boost::mpl::end<types>::type>::read(ar, v, t))
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{
ar.stream().setstate(std::ios::failbit);
return false;
}
ar.end_variant();
return true;
}
};
template <template <bool> class Archive, BOOST_VARIANT_ENUM_PARAMS(typename T)>
struct serializer<Archive<true>, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
{
typedef boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> variant_type;
//typedef typename Archive<true>::variant_tag_type variant_tag_type;
struct visitor : public boost::static_visitor<bool>
{
Archive<true> &ar;
visitor(Archive<true> &a) : ar(a) { }
template <class T>
bool operator ()(T &rv) const
{
ar.begin_variant();
ar.write_variant_tag(variant_serialization_traits<Archive<true>, T>::get_tag());
if(!::do_serialize(ar, rv))
{
ar.stream().setstate(std::ios::failbit);
return false;
}
ar.end_variant();
return true;
}
};
static bool serialize(Archive<true> &ar, variant_type &v) {
return boost::apply_visitor(visitor(ar), v);
}
};