Converters.h

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#pragma once

#include <string>
#include <codecvt>
#include <type_traits>

#include "swCommonLib/Common//RTTR.h"



class Convert
{
private:

    template< typename SrcType >
    static inline std::string           EnumToString        ( SrcType defaultVal );

    template< typename SrcType >
    static inline SrcType               StringToEnum        ( const std::string& value, SrcType defaultValue );

public:

    template< typename SrcType >
    static inline typename std::enable_if< std::is_enum< SrcType >::value, std::string >::type
                                        ToString            ( const SrcType& val );

    template< typename SrcType >
    static inline typename std::enable_if< std::is_enum< SrcType >::value, SrcType >::type
                                        FromString          ( const std::string& val, const SrcType& defaultValue );

    template< typename SrcType >
    static inline typename std::enable_if< !std::is_enum< SrcType >::value, std::string >::type
                                        ToString            ( const SrcType& val );

    template< typename SrcType >
    static inline typename std::enable_if< !std::is_enum< SrcType >::value, SrcType >::type
                                        FromString          ( const std::string& val, const SrcType& defaultValue );



    template<>
    static inline typename std::enable_if< !std::is_enum< std::wstring >::value, std::string >::type
                                        ToString< std::wstring >    ( const std::wstring& value );

    template<>
    static inline typename std::enable_if< !std::is_enum< std::wstring >::value, std::wstring >::type
                                        FromString< std::wstring >  ( const std::string& value, const std::wstring& defaultValue );

};


template< typename SrcType >
inline typename std::enable_if< !std::is_enum< SrcType >::value, std::string >::type
                            Convert::ToString       ( const SrcType& val )
{
    return std::to_string( val );
}

template< typename SrcType >
inline typename std::enable_if< !std::is_enum< SrcType >::value, SrcType >::type
                            Convert::FromString     ( const std::string& val, const SrcType& defaultValue )
{
    static_assert( false, "Specialize template" );
    return SrcType();
}


//====================================================================================//
//          Public template specialization for enum types
//====================================================================================//

template< typename SrcType >
inline typename std::enable_if< std::is_enum< SrcType >::value, std::string >::type
                            Convert::ToString       ( const SrcType& val )
{
    return EnumToString( val );
}

template< typename SrcType >
inline typename std::enable_if< std::is_enum< SrcType >::value, SrcType >::type
                            Convert::FromString     ( const std::string& val, const SrcType& defaultValue )
{
    return StringToEnum( val, defaultValue );
}

//====================================================================================//
//          Wstring to string   
//====================================================================================//

template<>
inline typename std::enable_if< !std::is_enum< std::wstring >::value, std::string >::type
                            Convert::ToString< std::wstring >   ( const std::wstring& value )
{
    typedef std::codecvt_utf8<wchar_t> convert_type;
    std::wstring_convert<convert_type, wchar_t> converter;
    return converter.to_bytes( value );
}

template<>
inline typename std::enable_if< !std::is_enum< std::wstring >::value, std::wstring >::type
                            Convert::FromString< std::wstring > ( const std::string& value, const std::wstring& defaultValue )
{
    typedef std::codecvt_utf8<wchar_t> convert_type;
    std::wstring_convert<convert_type, wchar_t> converter;
    return converter.from_bytes( value );
}

//====================================================================================//
//          Private enum helpers
//====================================================================================//


template< typename SrcType >
std::string             Convert::EnumToString       ( SrcType value )
{
    static_assert( std::is_enum< SrcType >::value, "Type is not enum" );

    auto type = rttr::type::get< SrcType >();
    
    assert( type.is_valid() );      
    assert( type.is_enumeration() );
    
    rttr::enumeration enumVal = type.get_enumeration();

    return enumVal.value_to_name( value );
}


template< typename SrcType >
SrcType             Convert::StringToEnum       ( const std::string& value, SrcType defaultValue )
{
    static_assert( std::is_enum< SrcType >::value, "Type is not enum" );

    auto type = rttr::type::get< SrcType >();

    assert( type.is_valid() );      
    assert( type.is_enumeration() );

    rttr::enumeration enumVal = type.get_enumeration();

    rttr::variant result = enumVal.value_to_name( value );
    if( !result.is_valid() )
        return defaultValue;

    return result.get_value< SrcType >();
}