ValueContainer.h

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// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
// This software owned by Onix Solutions Limited [OnixS] and is
// protected by copyright law and international copyright treaties.
//
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// OnixS Software Services Agreement (the Agreement) and Customer end user license
// agreements granting a non-assignable, non-transferable and non-exclusive license
// to use the software for it's own data processing purposes under the terms defined
// in the Agreement.
//
// Except as otherwise granted within the terms of the Agreement, copying or
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// amendments to this copyright notice, are expressly prohibited.
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#pragma once
 
#include <OnixS/CME/MDH/ABI.h>
#include <OnixS/CME/MDH/messaging/Memory.h>
 
#include <new>
 
ONIXS_CMEMDH_MESSAGING_TAGBASED_NAMESPACE_BEGIN

class ValueContainer
{
    enum
    {
        Capacity = 16
    };
 
    Byte bytes_[Capacity];

    void* place() noexcept
    {
        return static_cast<void*>(bytes_);
    }

    const void* place() const noexcept
    {
        return static_cast<const void*>(bytes_);
    }
 
public:
    ValueContainer() = default;

    template <typename Value>
    ONIXS_CMEMDH_NODISCARD Value& get() noexcept
    {
        static_assert(
            (sizeof(Value) <= static_cast<size_t>(Capacity)),
            "Capacity is not sufficient for storing values of the given type."
        );
 
        return *static_cast<Value*>(place());
    }

    template <typename Value>
    ONIXS_CMEMDH_NODISCARD const Value& get() const noexcept
    {
        static_assert(
            (sizeof(Value) <= static_cast<size_t>(Capacity)),
            "Capacity of the storage is not sufficient to store values of the specified type."
        );
 
        return *static_cast<const Value*>(place());
    }

    template <class Value>
    ValueContainer& assign(const Value& value) noexcept
    {
        static_assert(
            (sizeof(Value) <= static_cast<size_t>(Capacity)),
            "Capacity of the storage is not sufficient to store values of the specified type."
        );
 
        static_assert(std::is_nothrow_copy_constructible<Value>::value, "must be noexcept");
 
        new (place()) Value(value);
 
        return *this;
    }
};
 
ONIXS_CMEMDH_MESSAGING_TAGBASED_NAMESPACE_END