// This file is under GNU General Public License 3.0
// see LICENSE.txt

#ifndef PEP_DATATYPES_STRING_VIEW_HH
#define PEP_DATATYPES_STRING_VIEW_HH

#if (__cplusplus >= 201606)  // std::string_view is C++17.
#   include <string_view>

namespace pEp
{
    template<class CharT>
    using basic_string_view = std::basic_string_view<CharT>;
    
    typedef std::string_view       string_view;
    typedef std::u16string_view u16string_view;
    typedef std::u32string_view u32string_view;
}

#else // in C++11 / C++14 use boost::string_view instead.
#   include <boost/utility/string_view.hpp>

namespace pEp
{
    template<class CharT>
    using basic_string_view = boost::basic_string_view<CharT>;
    
    typedef boost::string_view       string_view;
    typedef boost::u16string_view u16string_view;
    typedef boost::u32string_view u32string_view;

    // boost::string_view does not provide these operations, neither by boost nor by the stdlib. :-(
    template<class CharT>
    inline
    std::basic_string<CharT>& operator+=(std::basic_string<CharT>& s, const basic_string_view<CharT> v)
    {
        s.append(v.data(), v.size());
        return s;
    }

    template<class CharT>
    inline
    std::basic_string<CharT> operator+(std::basic_string<CharT> s, const basic_string_view<CharT> v)
    {
        return s += v;
    }

 
//    using ::std::operator+=;
//    using ::boost::operator+=;
} // end of namespace pEp

#endif // C++17 switch


namespace pEp
{
    constexpr
    string_view operator""_sv(const char* s, size_t sz) noexcept
    {
        return string_view(s,sz);
    }
}

#endif // PEP_DATATYPES_STRING_VIEW_HH