#ifndef BOOST_UTF8_CODECVT_FACET_HPP
#define BOOST_UTF8_CODECVT_FACET_HPP

// MS compatible compilers support #pragma once
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif

/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
// utf8_codecvt_facet.hpp

// Copyright © 2001 Ronald Garcia, Indiana University (garcia@osl.iu.edu)
// Andrew Lumsdaine, Indiana University (lums@osl.iu.edu). Permission to copy, 
// use, modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided "as is"
// without express or implied warranty, and with no claim as to its suitability
// for any purpose.

// Note:(Robert Ramey).  I have made the following alterations in the original
// code.
// a) Rendered utf8_codecvt<wchar_t, char>  with using templates
// b) Move longer functions outside class definition to prevent inlining
// and make code smaller
// c) added on a derived class to permit translation to/from current
// locale to utf8

//  See http://www.boost.org for updates, documentation, and revision history.

// archives stored as text - note these ar templated on the basic
// stream templates to accommodate wide (and other?) kind of characters
//
// note the fact that on libraries without wide characters, ostream is
// is not a specialization of basic_ostream which in fact is not defined
// in such cases.   So we can't use basic_ostream<OStream::char_type> but rather
// use two template parameters
//
// utf8_codecvt_facet
//   This is an implementation of a std::codecvt facet for translating 
//   from UTF-8 externally to UCS-4.  Note that this is not tied to
//   any specific types in order to allow customization on platforms
//   where wchar_t is not big enough.
//
// NOTES:  The current implementation jumps through some unpleasant hoops in
// order to deal with signed character types.  As a std::codecvt_base::result,
// it is necessary  for the ExternType to be convertible to unsigned  char.
// I chose not to tie the extern_type explicitly to char. But if any combination
// of types other than <wchar_t,char_t> is used, then std::codecvt must be
// specialized on those types for this to work.

#include <locale>
// for mbstate_t
#include <wchar.h>

#include <boost/program_options/config.hpp>

#include <boost/detail/workaround.hpp>
#if BOOST_WORKAROUND(__BORLANDC__,BOOST_TESTED_AT(0x551))
    #ifndef _RWSTD_NO_NAMESPACE
    using std::codecvt;
    using std::min;
    #ifdef _RWSTD_NO_MBSTATE_T
    using std::mbstate_t;
    #endif
    #endif
#elif defined(__COMO__) || defined(_MSC_VER) && _MSC_VER <= 1300 
    typedef ::mbstate_t mbstate_t;
#elif defined(BOOST_NO_STDC_NAMESPACE)
    typedef std::mbstate_t mbstate_t;
    namespace std{ 
        using ::codecvt; 
    } // namespace std
#endif

// maximum lenght of a multibyte string
#define MB_LENGTH_MAX 8

namespace boost { namespace program_options { namespace detail {

struct BOOST_PROGRAM_OPTIONS_DECL utf8_codecvt_facet_wchar_t :
    public std::codecvt<wchar_t, char, mbstate_t>  
{
public:
    explicit utf8_codecvt_facet_wchar_t(std::size_t no_locale_manage=0)
        : std::codecvt<wchar_t, char, mbstate_t>(no_locale_manage) 
    {}
protected:
    virtual std::codecvt_base::result do_in(
        mbstate_t& state, 
        const char * from,
        const char * from_end, 
        const char * & from_next,
        wchar_t * to, 
        wchar_t * to_end, 
        wchar_t*& to_next
    ) const;

    virtual std::codecvt_base::result do_out(
        mbstate_t & state, const wchar_t * from,
        const wchar_t * from_end, const wchar_t*  & from_next,
        char * to, char * to_end, char * & to_next
    ) const;

    bool invalid_continuing_octet(unsigned char octet_1) const {
        return (octet_1 < 0x80|| 0xbf< octet_1);
    }

    bool invalid_leading_octet(unsigned char octet_1)   const {
        return (0x7f < octet_1 && octet_1 < 0xc0) ||
            (octet_1 > 0xfd);
    }

    // continuing octets = octets except for the leading octet
    static unsigned int get_cont_octet_count(unsigned   char lead_octet) {
        return get_octet_count(lead_octet) - 1;
    }

    static unsigned int get_octet_count(unsigned char   lead_octet);

    // How many "continuing octets" will be needed for this word
    // ==   total octets - 1.
    int get_cont_octet_out_count(wchar_t word) const ;

    virtual bool do_always_noconv() const throw() { return false; }

    // UTF-8 isn't really stateful since we rewind on partial conversions
    virtual std::codecvt_base::result do_unshift(
        mbstate_t&,
        char * from,
        char * to,
        char * & next
    ) const 
    {
        next = from;
        return ok;
    }

    virtual int do_encoding() const throw() {
        const int variable_byte_external_encoding=0;
        return variable_byte_external_encoding;
    }

    // How many char objects can I process to get <= max_limit
    // wchar_t objects?
    virtual int do_length(
        mbstate_t &,
        const char * from,
        const char * from_end, 
        std::size_t max_limit
#if BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
        ) const throw();
#else
        ) const;
#endif

    // Largest possible value do_length(state,from,from_end,1) could return.
    virtual int do_max_length() const throw () {
        return 6; // largest UTF-8 encoding of a UCS-4 character
    }
};

#if 0 // not used - incorrect in any case
// Robert Ramey - use the above to make a code converter from multi-byte
// char strings to utf8 encoding
struct utf8_codecvt_facet_char : public utf8_codecvt_facet_wchar_t
{
    typedef utf8_codecvt_facet_wchar_t base_class;
public:
    explicit utf8_codecvt_facet_char(size_t no_locale_manage=0)
        : base_class(no_locale_manage)
    {}
protected:
    virtual std::codecvt_base::result do_in(
        mbstate_t & state, 
        const char * from, 
        const char * from_end, 
        const char * & from_next,
        char * to, 
        char * to_end, 
        char * & to_next
    ) const;

    virtual std::codecvt_base::result do_out(
        mbstate_t & state, 
        const char * from,
        const char * from_end, 
        const char*  & from_next,
        char * to, 
        char * to_end, 
        char * & to_next
    ) const;

    // How many char objects can I process to get <= max_limit
    // char objects?
    virtual int do_length(
        const mbstate_t&, 
        const char * from,
        const char * from_end, 
        size_t max_limit
    ) const;
};
#endif

template<class Internal, class External>
struct utf8_codecvt_facet
{};

template<>
struct BOOST_PROGRAM_OPTIONS_DECL utf8_codecvt_facet<wchar_t, char>
    : public utf8_codecvt_facet_wchar_t
{};

#if 0
template<>
struct utf8_codecvt_facet<char, char>
    : public utf8_codecvt_facet_char
{};
#endif

}}}

#endif // BOOST_UTF8_CODECVT_FACET_HPP
