RscReadEnumerator.hxx

//
//  Copyright PHOENIX CONTACT Electronics GmbH
//
#pragma once
#include "Arp/System/Rsc/Services/Rsc.h"
#include "Arp/System/Commons/Logging.h"
#include "Arp/System/Commons/Exceptions/Exceptions.h"
#include "Arp/System/Rsc/Services/RscException.hpp"
#include "Arp/System/Rsc/Services/IRscReadEnumerator.hxx"
#include "Arp/System/Rsc/Services/RscReader.hpp"
#include "Arp/System/Rsc/Services/RscArrayReader.hpp"


namespace Arp { namespace System { namespace Rsc { namespace Services
{

template<class T>
class RscReadEnumerator : public IRscReadEnumerator<T>
{
public: // construction/destruction
    RscReadEnumerator(RscReader& rscReader, bool isArrayEnumerator);
    RscReadEnumerator(const RscReadEnumerator& arg) = default;
    ~RscReadEnumerator(void);

public: // operations of IRscReadEnumerator
    size_t  BeginRead(void)override;
    bool    ReadNext(T& current)override;
    bool    ReadNext(RscArrayReader& current)override;
    void    EndRead(void)override;

private: // deleted methods
    RscReadEnumerator& operator=(const RscReadEnumerator& arg) = delete;

private: // fields
    RemotingReader& remotingReader;
    size_t          arrayLength = UndefinedArrayLength;
    bool            isArrayEnumerator;
    RscType         rscType;
    bool            ended = false;
    size_t          fieldCount = 0;

public:
    static constexpr size_t UndefinedArrayLength = std::numeric_limits<size_t>::max();
};

// inline methods of class RscEnumerator
template<class T>
inline RscReadEnumerator<T>::RscReadEnumerator(RscReader& rscReader, bool isArrayEnumeratorArg)
    : remotingReader(rscReader.GetRemotingReader())
    , isArrayEnumerator(isArrayEnumeratorArg)
    , rscType(GetRscTypeFrom(T()))
    , fieldCount(StructInfo<T>().FieldCount)
{
}

template<class T>
inline RscReadEnumerator<T>::~RscReadEnumerator()
{
    if(!ended)
    {
        Log::Error("Rsc Enumerating was not ended properly, call EndRead() method when reading was finished.");
    }
}

template<class T>
inline size_t RscReadEnumerator<T>::BeginRead(void)
{
    if(this->isArrayEnumerator)
    {
        this->remotingReader.ReadTag(RscType::Array);
        if(this->rscType == RscType::Struct)
        {
            this->remotingReader.ReadBeginStruct(this->fieldCount);
        }
        else
        {
            this->remotingReader.ReadTag(this->rscType);
        }
        this->arrayLength = this->remotingReader.ReadArrayLength();
    }
    else // use standard enumerator
    {
        this->remotingReader.ReadTag(RscType::Enumerator);
    }
    return this->arrayLength;
}

template<class T>
inline bool RscReadEnumerator<T>::ReadNext(T& current)
{
    if(this->isArrayEnumerator)
    {
        if(this->arrayLength == 0)
        {
            return false;    // end of array reached
        }
        // else
        --this->arrayLength;
    }
    else // use standard enumerator
    {
        if(this->ended)
        {
            return false;
        }
        RscType currentTypeCode = this->remotingReader.ReadEnumeratorTag(this->ended);
        if(this->ended)
        {
            return false; // end of sequence
        }
        // check if 'currentTypeCode' matches 'T' else ProtocolViolation occurs
        if(currentTypeCode != this->rscType)
        {
            throw RscException((int)RscErrors::ProtocolViolation, "Read false enumerator Tag: expected '{0}', received '{1}'", this->rscType, currentTypeCode);
        }
        if(this->rscType == RscType::Struct)
        {
            size_t readFieldCount = this->remotingReader.ReadFieldCount();
            if(readFieldCount != this->fieldCount)
            {
                throw RscException((int)RscErrors::ProtocolViolation, "Read false struct field count: expected '{0}', received '{1}'", this->fieldCount, readFieldCount);
            }
        }
    }
    RscValueAdapter<T> valueAdapter(current);
    valueAdapter.Read(this->remotingReader, false);
    return true;
}

template<class T>
inline bool RscReadEnumerator<T>::ReadNext(RscArrayReader& current)
{
    if (this->arrayLength == 0)
    {
        return false;    // end of array reached
    }
    // else
    this->remotingReader.ReadTag(RscType::Array);
    RscType elementType = this->remotingReader.ReadTag();
    size_t arraySize = this->remotingReader.ReadArrayLength();
    current = RscArrayReader(arraySize, elementType, this->remotingReader);
    return true;
}

template<class T>
inline void RscReadEnumerator<T>::EndRead(void)
{
    if(this->isArrayEnumerator)
    {
        if(this->arrayLength != 0)
        {
            throw InvalidOperationException("End of array enumerator was not reached yet");
        }
        this->ended = true;

    }
    else // use standard enumerator
    {
    }
}

}}}} // end of namespace Arp::System::Rsc::Services