//  test_codecvt.hpp  ------------------------------------------------------------------//

//  Copyright Beman Dawes 2009, 2010

//  Distributed under the Boost Software License, Version 1.0.
//  See http://www.boost.org/LICENSE_1_0.txt

//  Library home page: http://www.boost.org/libs/filesystem

#ifndef BOOST_FILESYSTEM_TEST_CODECVT_HPP
#define BOOST_FILESYSTEM_TEST_CODECVT_HPP

#include <boost/filesystem/config.hpp>
#include <locale>
#include <cwchar> // for mbstate_t

//------------------------------------------------------------------------------------//
//                                                                                    //
//                              class test_codecvt                                    //
//                                                                                    //
//  Warning: partial implementation; even do_in and do_out only partially meet the    //
//  standard library specifications as the "to" buffer must hold the entire result.   //
//                                                                                    //
//  The value of a wide character is the value of the corresponding narrow character  //
//  plus 1. This ensures that compares against expected values will fail if the       //
//  code conversion did not occur as expected.                                        //
//                                                                                    //
//------------------------------------------------------------------------------------//

class test_codecvt :
    public std::codecvt< wchar_t, char, std::mbstate_t >
{
public:
    explicit test_codecvt() :
        std::codecvt< wchar_t, char, std::mbstate_t >()
    {
    }

protected:
    virtual bool do_always_noconv() const throw() { return false; }
    virtual int do_encoding() const throw() { return 0; }

    virtual std::codecvt_base::result do_in(std::mbstate_t&, const char* from, const char* from_end, const char*& from_next, wchar_t* to, wchar_t* to_end, wchar_t*& to_next) const
    {
        for (; from != from_end && to != to_end; ++from, ++to)
            *to = wchar_t(*from + 1);
        if (to == to_end)
            return error;
        *to = L'\0';
        from_next = from;
        to_next = to;
        return ok;
    }

    virtual std::codecvt_base::result do_out(std::mbstate_t&, const wchar_t* from, const wchar_t* from_end, const wchar_t*& from_next, char* to, char* to_end, char*& to_next) const
    {
        for (; from != from_end && to != to_end; ++from, ++to)
            *to = static_cast< char >(*from - 1);
        if (to == to_end)
            return error;
        *to = '\0';
        from_next = from;
        to_next = to;
        return ok;
    }

    virtual std::codecvt_base::result do_unshift(std::mbstate_t&, char* /*from*/, char* /*to*/, char*& /*next*/) const { return ok; }
    virtual int do_length(std::mbstate_t&, const char* /*from*/, const char* /*from_end*/, std::size_t /*max*/) const { return 0; }
    virtual int do_max_length() const throw() { return 0; }
};

#endif // BOOST_FILESYSTEM_TEST_CODECVT_HPP
