tuple.h

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/*
 * Copyright (c) 2021 Universita' degli Studi di Napoli Federico II
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Stefano Avallone <stavallo@unina.it>
 */
 
#ifndef TUPLE_H
#define TUPLE_H
 
#include <ns3/attribute-helper.h>
#include <ns3/string.h>
 
#include <algorithm>
#include <sstream>
#include <tuple>
#include <type_traits>
#include <utility>
 
namespace ns3
{
 
template <class... Args>
std::ostream&
operator<<(std::ostream& os, const std::tuple<Args...>& t)
{
    std::apply(
        [&os](auto&&... args) {
            std::size_t n{0};
            ((os << args << (++n != sizeof...(Args) ? ", " : "")), ...);
        },
        t);
    return os;
}
 
// Doxygen for this class is auto-generated by
// utils/print-introspected-doxygen.h
 
template <class... Args>
class TupleValue : public AttributeValue
{
  public:
    typedef std::tuple<Args...> value_type;
    typedef std::tuple<std::invoke_result_t<decltype(&Args::Get), Args>...> result_type;
 
    TupleValue();
 
    TupleValue(const result_type& value);
 
    Ptr<AttributeValue> Copy() const override;
    bool DeserializeFromString(std::string value, Ptr<const AttributeChecker> checker) override;
    std::string SerializeToString(Ptr<const AttributeChecker> checker) const override;
 
    result_type Get() const;
    void Set(const result_type& value);
 
    value_type GetValue() const;
 
    template <typename T>
    bool GetAccessor(T& value) const;
 
  private:
    template <std::size_t... Is>
    bool SetValueImpl(std::index_sequence<Is...>, const std::vector<Ptr<AttributeValue>>& values);
 
    value_type m_value; 
};
 
template <class T1, class T2>
auto MakeTupleValue(T2 t);
 
class TupleChecker : public AttributeChecker
{
  public:
    virtual const std::vector<Ptr<const AttributeChecker>>& GetCheckers() const = 0;
};
 
template <class... Args, class... Ts>
Ptr<const AttributeChecker> MakeTupleChecker(Ts... checkers);
 
template <class... Args, class T1>
Ptr<const AttributeAccessor> MakeTupleAccessor(T1 a1);
 
template <class... Args, class T1, class T2>
Ptr<const AttributeAccessor> MakeTupleAccessor(T1 a1, T2 a2);
 
} // namespace ns3
 
/*****************************************************************************
 * Implementation below
 *****************************************************************************/
 
namespace ns3
{
 
template <class... Args>
TupleValue<Args...>::TupleValue()
    : m_value(std::make_tuple(Args()...))
{
}
 
template <class... Args>
TupleValue<Args...>::TupleValue(const result_type& value)
{
    Set(value);
}
 
template <class... Args>
Ptr<AttributeValue>
TupleValue<Args...>::Copy() const
{
    return Create<TupleValue<Args...>>(Get());
}
 
template <class... Args>
template <std::size_t... Is>
bool
TupleValue<Args...>::SetValueImpl(std::index_sequence<Is...>,
                                  const std::vector<Ptr<AttributeValue>>& values)
{
    auto valueTuple = std::make_tuple(DynamicCast<Args>(values[Is])...);
 
    bool ok = ((std::get<Is>(valueTuple) != nullptr) && ...);
 
    if (ok)
    {
        m_value = std::make_tuple(Args(*std::get<Is>(valueTuple))...);
    }
    return ok;
}
 
template <class... Args>
bool
TupleValue<Args...>::DeserializeFromString(std::string value, Ptr<const AttributeChecker> checker)
{
    auto tupleChecker = DynamicCast<const TupleChecker>(checker);
    if (!tupleChecker)
    {
        return false;
    }
 
    auto count = tupleChecker->GetCheckers().size();
    if (count != sizeof...(Args))
    {
        return false;
    }
 
    if (value.empty() || value.front() != '{' || value.back() != '}')
    {
        return false;
    }
 
    value.erase(value.begin());
    value.pop_back();
    std::replace(value.data(), value.data() + value.size(), ',', ' ');
 
    std::istringstream iss(value);
    std::vector<Ptr<AttributeValue>> values;
    std::size_t i = 0;
 
    while (iss >> value)
    {
        if (i >= count)
        {
            return false;
        }
        values.push_back(tupleChecker->GetCheckers().at(i++)->CreateValidValue(StringValue(value)));
        if (!values.back())
        {
            return false;
        }
    }
 
    if (i != count)
    {
        return false;
    }
 
    return SetValueImpl(std::index_sequence_for<Args...>{}, values);
}
 
template <class... Args>
std::string
TupleValue<Args...>::SerializeToString(Ptr<const AttributeChecker> checker) const
{
    std::ostringstream oss;
    oss << "{" << Get() << "}";
    return oss.str();
}
 
template <class... Args>
typename TupleValue<Args...>::result_type
TupleValue<Args...>::Get() const
{
    return std::apply([](Args... values) { return std::make_tuple(values.Get()...); }, m_value);
}
 
template <class... Args>
void
TupleValue<Args...>::Set(const typename TupleValue<Args...>::result_type& value)
{
    m_value = std::apply([](auto&&... args) { return std::make_tuple(Args(args)...); }, value);
}
 
template <class... Args>
typename TupleValue<Args...>::value_type
TupleValue<Args...>::GetValue() const
{
    return m_value;
}
 
template <class... Args>
template <typename T>
bool
TupleValue<Args...>::GetAccessor(T& value) const
{
    value = T(Get());
    return true;
}
 
// This internal class defines templated TupleChecker class that is instantiated
// in MakeTupleChecker. The non-templated base ns3::TupleChecker is returned in that
// function. This is the same pattern as ObjectPtrContainer.
namespace internal
{
 
template <class... Args>
class TupleChecker : public ns3::TupleChecker
{
  public:
    template <class... Ts>
    TupleChecker(Ts... checkers)
        : m_checkers{checkers...}
    {
    }
 
    const std::vector<Ptr<const AttributeChecker>>& GetCheckers() const override
    {
        return m_checkers;
    }
 
    bool Check(const AttributeValue& value) const override
    {
        const TupleValue<Args...>* v = dynamic_cast<const TupleValue<Args...>*>(&value);
        if (v == nullptr)
        {
            return false;
        }
        return std::apply(
            [this](Args... values) {
                std::size_t n{0};
                return (m_checkers[n++]->Check(values) && ...);
            },
            v->GetValue());
    }
 
    std::string GetValueTypeName() const override
    {
        return "ns3::TupleValue";
    }
 
    bool HasUnderlyingTypeInformation() const override
    {
        return false;
    }
 
    std::string GetUnderlyingTypeInformation() const override
    {
        return "";
    }
 
    Ptr<AttributeValue> Create() const override
    {
        return ns3::Create<TupleValue<Args...>>();
    }
 
    bool Copy(const AttributeValue& source, AttributeValue& destination) const override
    {
        const TupleValue<Args...>* src = dynamic_cast<const TupleValue<Args...>*>(&source);
        TupleValue<Args...>* dst = dynamic_cast<TupleValue<Args...>*>(&destination);
        if (src == nullptr || dst == nullptr)
        {
            return false;
        }
        *dst = *src;
        return true;
    }
 
  private:
    std::vector<Ptr<const AttributeChecker>> m_checkers; 
};
 
template <class... Args>
struct TupleHelper
{
    template <class... Ts>
    static Ptr<const AttributeChecker> MakeTupleChecker(Ts... checkers)
    {
        return Create<internal::TupleChecker<Args...>>(checkers...);
    }
 
    template <class T1>
    static Ptr<const AttributeAccessor> MakeTupleAccessor(T1 a1)
    {
        return MakeAccessorHelper<TupleValue<Args...>>(a1);
    }
 
    template <class T1, class T2>
    static Ptr<const AttributeAccessor> MakeTupleAccessor(T1 a1, T2 a2)
    {
        return MakeAccessorHelper<TupleValue<Args...>>(a1, a2);
    }
};
 
template <class... Args>
struct TupleHelper<std::tuple<Args...>>
{
    static TupleValue<Args...> MakeTupleValue(const typename TupleValue<Args...>::result_type& t)
    {
        return TupleValue<Args...>(t);
    }
 
    template <class... Ts>
    static Ptr<const AttributeChecker> MakeTupleChecker(Ts... checkers)
    {
        return Create<internal::TupleChecker<Args...>>(checkers...);
    }
 
    template <class T1>
    static Ptr<const AttributeAccessor> MakeTupleAccessor(T1 a1)
    {
        return MakeAccessorHelper<TupleValue<Args...>>(a1);
    }
 
    template <class T1, class T2>
    static Ptr<const AttributeAccessor> MakeTupleAccessor(T1 a1, T2 a2)
    {
        return MakeAccessorHelper<TupleValue<Args...>>(a1, a2);
    }
};
 
} // namespace internal
 
template <class T1, class T2>
auto
MakeTupleValue(T2 t)
{
    return internal::TupleHelper<T1>::MakeTupleValue(t);
}
 
template <class... Args, class... Ts>
Ptr<const AttributeChecker>
MakeTupleChecker(Ts... checkers)
{
    return internal::TupleHelper<Args...>::template MakeTupleChecker<Ts...>(checkers...);
}
 
template <class... Args, class T1>
Ptr<const AttributeAccessor>
MakeTupleAccessor(T1 a1)
{
    return internal::TupleHelper<Args...>::template MakeTupleAccessor<T1>(a1);
}
 
template <class... Args, class T1, class T2>
Ptr<const AttributeAccessor>
MakeTupleAccessor(T1 a1, T2 a2)
{
    return internal::TupleHelper<Args...>::template MakeTupleAccessor<T1, T2>(a1, a2);
}
 
} // namespace ns3
 
#endif // TUPLE_H