StringWrapper.h

//
// Copyright 2015 - 2024 (C). Alex Robenko. All rights reserved.
//
 
// This file is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// 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, see <http://www.gnu.org/licenses/>.
 
 
#pragma once
 
 
#pragma once
 
#include <cstdint>
#include <cassert>
#include <memory>
#include <limits>
 
#include "comms/comms.h"
 
#include "FieldWrapper.h"
 
namespace cc_tools_qt
{
 
namespace field_wrapper
{
 
class CC_API StringWrapper : public FieldWrapper
{
public:
 
    typedef std::unique_ptr<StringWrapper> Ptr;
 
    StringWrapper();
    virtual ~StringWrapper() noexcept;
 
    QString getValue() const;
 
    void setValue(const QString& val);
 
    int maxSize() const;
 
    Ptr clone();
 
protected:
    virtual QString getValueImpl() const = 0;
    virtual void setValueImpl(const QString& val) = 0;
    virtual int maxSizeImpl() const = 0;
    virtual Ptr cloneImpl() = 0;
 
    void dispatchImpl(FieldWrapperHandler& handler);
};
 
template <typename TField>
class StringWrapperT : public FieldWrapperT<StringWrapper, TField>
{
    using Base = FieldWrapperT<StringWrapper, TField>;
    using Field = TField;
 
public:
    using SerialisedSeq = typename Base::SerialisedSeq;
    using Ptr = typename Base::Ptr;
 
    explicit StringWrapperT(Field& fieldRef)
      : Base(fieldRef)
    {
    }
 
    StringWrapperT(const StringWrapperT&) = default;
    StringWrapperT(StringWrapperT&&) = default;
    virtual ~StringWrapperT() noexcept = default;
 
    StringWrapperT& operator=(const StringWrapperT&) = delete;
 
protected:
 
    virtual QString getValueImpl() const override
    {
        auto& strField = Base::field();
        return QString::fromUtf8(strField.getValue().c_str(), static_cast<int>(strField.getValue().size()));
    }
 
    virtual void setValueImpl(const QString& val) override
    {
        Base::field().setValue(val.toStdString().c_str());
    }
 
    virtual bool setSerialisedValueImpl([[maybe_unused]] const SerialisedSeq& value) override
    {
        [[maybe_unused]] static constexpr bool Must_not_be_called = false;
        assert(Must_not_be_called); 
        return false;
    }
 
    virtual int maxSizeImpl() const override
    {
        return maxSizeInternal(SizeExistanceTag());
    }
 
    virtual Ptr cloneImpl() override
    {
        return Ptr(new StringWrapperT<TField>(Base::field()));
    }
 
private:
    struct SizeFieldExistsTag {};
    struct SerLengthFieldExistsTag {};
    struct NoSizeFieldTag {};
 
    typedef typename std::conditional<
        Field::hasSizeFieldPrefix(),
        SizeFieldExistsTag,
        typename std::conditional<
            Field::hasSerLengthFieldPrefix(),
            SerLengthFieldExistsTag,
            NoSizeFieldTag
        >::type
    >::type SizeExistanceTag;
 
    template <typename TPrefixField>
    static int maxSizeByPrefix()
    {
        if (sizeof(int) <= TPrefixField::maxLength()) {
            return std::numeric_limits<int>::max();
        }
 
        auto shift =
            TPrefixField::maxLength() * std::numeric_limits<std::uint8_t>::digits;
 
        return static_cast<int>((1U << shift) - 1);
    }
 
    static int maxSizeInternal(SizeFieldExistsTag)
    {
        typedef typename Field::SizeFieldPrefix SizeField;
        return maxSizeByPrefix<SizeField>();
    }
 
    static int maxSizeInternal(SerLengthFieldExistsTag)
    {
        typedef typename Field::SerLengthFieldPrefix LengthField;
        return maxSizeByPrefix<LengthField>();
    }
 
    int maxSizeInternal(NoSizeFieldTag) const
    {
        return
            static_cast<int>(
                std::min(
                    static_cast<std::size_t>(std::numeric_limits<int>::max()),
                    Base::field().getValue().max_size()));
    }
};
 
using StringWrapperPtr = StringWrapper::Ptr;
 
template <typename TField>
StringWrapperPtr
makeStringWrapper(TField& field)
{
    return
        StringWrapperPtr(
            new StringWrapperT<TField>(field));
}
 
}  // namespace field_wrapper
 
}  // namespace cc_tools_qt