SerOffset.h

//
// Copyright 2015 - 2025 (C). Alex Robenko. All rights reserved.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
#pragma once
 
#include "comms/ErrorStatus.h"
#include "comms/util/access.h"
 
namespace comms
{
 
namespace field
{
 
namespace adapter
{
 
template <long long int TOffset, typename TBase>
class SerOffset : public TBase
{
    using BaseImpl = TBase;
    static const auto Offset = TOffset;
public:
 
    using ValueType = typename BaseImpl::ValueType;
    using SerialisedType = typename BaseImpl::SerialisedType;
    using Endian = typename BaseImpl::Endian;
 
    SerOffset() = default;
 
    explicit SerOffset(const ValueType& val)
      : BaseImpl(val)
    {
    }
 
    explicit SerOffset(ValueType&& val)
      : BaseImpl(std::move(val))
    {
    }
 
    SerOffset(const SerOffset&) = default;
    SerOffset(SerOffset&&) = default;
    SerOffset& operator=(const SerOffset&) = default;
    SerOffset& operator=(SerOffset&&) = default;
 
    template <typename TIter>
    ErrorStatus read(TIter& iter, std::size_t size)
    {
        if (size < BaseImpl::length()) {
            return ErrorStatus::NotEnoughData;
        }
 
        readNoStatus(iter);
        return ErrorStatus::Success;
    }
 
    template <typename TIter>
    void readNoStatus(TIter& iter)
    {
        auto serialisedValue =
            comms::util::readData<SerialisedType>(iter, Endian());
        BaseImpl::setValue(fromSerialised(serialisedValue));
    }
 
    template <typename TIter>
    ErrorStatus write(TIter& iter, std::size_t size) const
    {
        if (size < BaseImpl::length()) {
            return ErrorStatus::BufferOverflow;
        }
 
        writeNoStatus(iter);
        return ErrorStatus::Success;
    }
 
    template <typename TIter>
    void writeNoStatus(TIter& iter) const
    {
        comms::util::writeData(toSerialised(BaseImpl::getValue()), iter, Endian());
    }
 
    static constexpr SerialisedType toSerialised(ValueType val)
    {
        return adjustToSerialised(BaseImpl::toSerialised(val));
    }
 
    static constexpr ValueType fromSerialised(SerialisedType val)
    {
        return BaseImpl::fromSerialised(adjustFromSerialised(val));
    }
 
private:
    static SerialisedType adjustToSerialised(SerialisedType val)
    {
        return static_cast<SerialisedType>(Offset + val);
    }
 
    static SerialisedType adjustFromSerialised(SerialisedType val)
    {
        return static_cast<SerialisedType>((-Offset) + val);
    }
};
 
}  // namespace adapter
 
}  // namespace field
 
}  // namespace comms