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// Locale support (codecvt) -*- C++ -*-

// Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005

//  Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 2, or (at your option)

// any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along

// with this library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// USA.

// As a special exception, you may use this file as part of a free software

// library without restriction.  Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License.  This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

//

// ISO C++ 14882: 22.2.1.5 Template class codecvt

//

// Written by Benjamin Kosnik <bkoz@redhat.com>

/** @file bits/codecvt.h

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 */

#ifndef _CODECVT_H

#define _CODECVT_H 1

#pragma GCC system_header

  /// @brief  Empty base class for codecvt facet [22.2.1.5].

  class codecvt_base

  {

  public:

    enum result

    {

      ok,

      partial,

      error,

      noconv

    };

  };

  /**

   *  @brief  Common base for codecvt functions.

   *

   *  This template class provides implementations of the public functions

   *  that forward to the protected virtual functions.

   *

   *  This template also provides abstract stubs for the protected virtual

   *  functions.

  */

  template<typename _InternT, typename _ExternT, typename _StateT>

    class __codecvt_abstract_base

    : public locale::facet, public codecvt_base

    {

    public:

      // Types:

      typedef codecvt_base::result      result;

      typedef _InternT                  intern_type;

      typedef _ExternT                  extern_type;

      typedef _StateT                   state_type;

      // 22.2.1.5.1 codecvt members

      /**

       *  @brief  Convert from internal to external character set.

       *

       *  Converts input string of intern_type to output string of

       *  extern_type.  This is analogous to wcsrtombs.  It does this by

       *  calling codecvt::do_out.

       *

       *  The source and destination character sets are determined by the

       *  facet's locale, internal and external types.

       *

       *  The characters in [from,from_end) are converted and written to

       *  [to,to_end).  from_next and to_next are set to point to the

       *  character following the last successfully converted character,

       *  respectively.  If the result needed no conversion, from_next and

       *  to_next are not affected.

       *

       *  The @a state argument should be intialized if the input is at the

       *  beginning and carried from a previous call if continuing

       *  conversion.  There are no guarantees about how @a state is used.

       *

       *  The result returned is a member of codecvt_base::result.  If

       *  all the input is converted, returns codecvt_base::ok.  If no

       *  conversion is necessary, returns codecvt_base::noconv.  If

       *  the input ends early or there is insufficient space in the

       *  output, returns codecvt_base::partial.  Otherwise the

       *  conversion failed and codecvt_base::error is returned.

       *

       *  @param  state  Persistent conversion state data.

       *  @param  from  Start of input.

       *  @param  from_end  End of input.

       *  @param  from_next  Returns start of unconverted data.

       *  @param  to  Start of output buffer.

       *  @param  to_end  End of output buffer.

       *  @param  to_next  Returns start of unused output area.

       *  @return  codecvt_base::result.

      */

      result

      out(state_type& __state, const intern_type* __from,

          const intern_type* __from_end, const intern_type*& __from_next,

          extern_type* __to, extern_type* __to_end,

          extern_type*& __to_next) const

      {

        return this->do_out(__state, __from, __from_end, __from_next,

                            __to, __to_end, __to_next);

      }

      /**

       *  @brief  Reset conversion state.

       *

       *  Writes characters to output that would restore @a state to initial

       *  conditions.  The idea is that if a partial conversion occurs, then

       *  the converting the characters written by this function would leave

       *  the state in initial conditions, rather than partial conversion

       *  state.  It does this by calling codecvt::do_unshift().

       *

       *  For example, if 4 external characters always converted to 1 internal

       *  character, and input to in() had 6 external characters with state

       *  saved, this function would write two characters to the output and

       *  set the state to initialized conditions.

       *

       *  The source and destination character sets are determined by the

       *  facet's locale, internal and external types.

       *

       *  The result returned is a member of codecvt_base::result.  If the

       *  state could be reset and data written, returns codecvt_base::ok.  If

       *  no conversion is necessary, returns codecvt_base::noconv.  If the

       *  output has insufficient space, returns codecvt_base::partial.

       *  Otherwise the reset failed and codecvt_base::error is returned.

       *

       *  @param  state  Persistent conversion state data.

       *  @param  to  Start of output buffer.

       *  @param  to_end  End of output buffer.

       *  @param  to_next  Returns start of unused output area.

       *  @return  codecvt_base::result.

      */

      result

      unshift(state_type& __state, extern_type* __to, extern_type* __to_end,

              extern_type*& __to_next) const

      { return this->do_unshift(__state, __to,__to_end,__to_next); }

      /**

       *  @brief  Convert from external to internal character set.

       *

       *  Converts input string of extern_type to output string of

       *  intern_type.  This is analogous to mbsrtowcs.  It does this by

       *  calling codecvt::do_in.

       *

       *  The source and destination character sets are determined by the

       *  facet's locale, internal and external types.

       *

       *  The characters in [from,from_end) are converted and written to

       *  [to,to_end).  from_next and to_next are set to point to the

       *  character following the last successfully converted character,

       *  respectively.  If the result needed no conversion, from_next and

       *  to_next are not affected.

       *

       *  The @a state argument should be intialized if the input is at the

       *  beginning and carried from a previous call if continuing

       *  conversion.  There are no guarantees about how @a state is used.

       *

       *  The result returned is a member of codecvt_base::result.  If

       *  all the input is converted, returns codecvt_base::ok.  If no

       *  conversion is necessary, returns codecvt_base::noconv.  If

       *  the input ends early or there is insufficient space in the

       *  output, returns codecvt_base::partial.  Otherwise the

       *  conversion failed and codecvt_base::error is returned.

       *

       *  @param  state  Persistent conversion state data.

       *  @param  from  Start of input.

       *  @param  from_end  End of input.

       *  @param  from_next  Returns start of unconverted data.

       *  @param  to  Start of output buffer.

       *  @param  to_end  End of output buffer.

       *  @param  to_next  Returns start of unused output area.

       *  @return  codecvt_base::result.

      */

      result

      in(state_type& __state, const extern_type* __from,

         const extern_type* __from_end, const extern_type*& __from_next,

         intern_type* __to, intern_type* __to_end,

         intern_type*& __to_next) const

      {

        return this->do_in(__state, __from, __from_end, __from_next,

                           __to, __to_end, __to_next);

      }

      int

      encoding() const throw()

      { return this->do_encoding(); }

      bool

      always_noconv() const throw()

      { return this->do_always_noconv(); }

      int

      length(state_type& __state, const extern_type* __from,

             const extern_type* __end, size_t __max) const

      { return this->do_length(__state, __from, __end, __max); }

      int

      max_length() const throw()

      { return this->do_max_length(); }

    protected:

      explicit

      __codecvt_abstract_base(size_t __refs = 0) : locale::facet(__refs) { }

      virtual

      ~__codecvt_abstract_base() { }

      /**

       *  @brief  Convert from internal to external character set.

       *

       *  Converts input string of intern_type to output string of

       *  extern_type.  This function is a hook for derived classes to change

       *  the value returned.  @see out for more information.

      */

      virtual result

      do_out(state_type& __state, const intern_type* __from,

             const intern_type* __from_end, const intern_type*& __from_next,

             extern_type* __to, extern_type* __to_end,

             extern_type*& __to_next) const = 0;

      virtual result

      do_unshift(state_type& __state, extern_type* __to,

                 extern_type* __to_end, extern_type*& __to_next) const = 0;

      virtual result

      do_in(state_type& __state, const extern_type* __from,

            const extern_type* __from_end, const extern_type*& __from_next,

            intern_type* __to, intern_type* __to_end,

            intern_type*& __to_next) const = 0;

      virtual int

      do_encoding() const throw() = 0;

      virtual bool

      do_always_noconv() const throw() = 0;

      virtual int

      do_length(state_type&, const extern_type* __from,

                const extern_type* __end, size_t __max) const = 0;

      virtual int

      do_max_length() const throw() = 0;

    };

  /// @brief class codecvt [22.2.1.5].

  /// NB: Generic, mostly useless implementation.

  template<typename _InternT, typename _ExternT, typename _StateT>

    class codecvt

    : public __codecvt_abstract_base<_InternT, _ExternT, _StateT>

    {

    public:

      // Types:

      typedef codecvt_base::result      result;

      typedef _InternT                  intern_type;

      typedef _ExternT                  extern_type;

      typedef _StateT                   state_type;

    protected:

      __c_locale                        _M_c_locale_codecvt;

    public:

      static locale::id                 id;

      explicit

      codecvt(size_t __refs = 0)

      : __codecvt_abstract_base<_InternT, _ExternT, _StateT> (__refs) { }

      explicit

      codecvt(__c_locale __cloc, size_t __refs = 0);

    protected:

      virtual

      ~codecvt() { }

      virtual result

      do_out(state_type& __state, const intern_type* __from,

             const intern_type* __from_end, const intern_type*& __from_next,

             extern_type* __to, extern_type* __to_end,

             extern_type*& __to_next) const;

      virtual result

      do_unshift(state_type& __state, extern_type* __to,

                 extern_type* __to_end, extern_type*& __to_next) const;

      virtual result

      do_in(state_type& __state, const extern_type* __from,

            const extern_type* __from_end, const extern_type*& __from_next,

            intern_type* __to, intern_type* __to_end,

            intern_type*& __to_next) const;

      virtual int

      do_encoding() const throw();

      virtual bool

      do_always_noconv() const throw();

      virtual int

      do_length(state_type&, const extern_type* __from,

                const extern_type* __end, size_t __max) const;

      virtual int

      do_max_length() const throw();

    };

  template<typename _InternT, typename _ExternT, typename _StateT>

    locale::id codecvt<_InternT, _ExternT, _StateT>::id;

  /// @brief class codecvt<char, char, mbstate_t> specialization.

  template<>

    class codecvt<char, char, mbstate_t>

    : public __codecvt_abstract_base<char, char, mbstate_t>

    {

    public:

      // Types:

      typedef char                      intern_type;

      typedef char                      extern_type;

      typedef mbstate_t                 state_type;

    protected:

      __c_locale                        _M_c_locale_codecvt;

    public:

      static locale::id id;

      explicit

      codecvt(size_t __refs = 0);

      explicit

      codecvt(__c_locale __cloc, size_t __refs = 0);

    protected:

      virtual

      ~codecvt();

      virtual result

      do_out(state_type& __state, const intern_type* __from,

             const intern_type* __from_end, const intern_type*& __from_next,

             extern_type* __to, extern_type* __to_end,

             extern_type*& __to_next) const;

      virtual result

      do_unshift(state_type& __state, extern_type* __to,

                 extern_type* __to_end, extern_type*& __to_next) const;

      virtual result

      do_in(state_type& __state, const extern_type* __from,

            const extern_type* __from_end, const extern_type*& __from_next,

            intern_type* __to, intern_type* __to_end,

            intern_type*& __to_next) const;

      virtual int

      do_encoding() const throw();

      virtual bool

      do_always_noconv() const throw();

      virtual int

      do_length(state_type&, const extern_type* __from,

                const extern_type* __end, size_t __max) const;

      virtual int

      do_max_length() const throw();

  };

#ifdef _GLIBCXX_USE_WCHAR_T

  /// @brief  class codecvt<wchar_t, char, mbstate_t> specialization.

  template<>

    class codecvt<wchar_t, char, mbstate_t>

    : public __codecvt_abstract_base<wchar_t, char, mbstate_t>

    {

    public:

      // Types:

      typedef wchar_t                   intern_type;

      typedef char                      extern_type;

      typedef mbstate_t                 state_type;

    protected:

      __c_locale                        _M_c_locale_codecvt;

    public:

      static locale::id                 id;

      explicit

      codecvt(size_t __refs = 0);

      explicit

      codecvt(__c_locale __cloc, size_t __refs = 0);

    protected:

      virtual

      ~codecvt();

      virtual result

      do_out(state_type& __state, const intern_type* __from,

             const intern_type* __from_end, const intern_type*& __from_next,

             extern_type* __to, extern_type* __to_end,

             extern_type*& __to_next) const;

      virtual result

      do_unshift(state_type& __state,

                 extern_type* __to, extern_type* __to_end,

                 extern_type*& __to_next) const;

      virtual result

      do_in(state_type& __state,

             const extern_type* __from, const extern_type* __from_end,

             const extern_type*& __from_next,

             intern_type* __to, intern_type* __to_end,

             intern_type*& __to_next) const;

      virtual

      int do_encoding() const throw();

      virtual

      bool do_always_noconv() const throw();

      virtual

      int do_length(state_type&, const extern_type* __from,

                    const extern_type* __end, size_t __max) const;

      virtual int

      do_max_length() const throw();

    };

#endif //_GLIBCXX_USE_WCHAR_T

  /// @brief class codecvt_byname [22.2.1.6].

  template<typename _InternT, typename _ExternT, typename _StateT>

    class codecvt_byname : public codecvt<_InternT, _ExternT, _StateT>

    {

    public:

      explicit

      codecvt_byname(const char* __s, size_t __refs = 0)

      : codecvt<_InternT, _ExternT, _StateT>(__refs)

      {

        if (std::strcmp(__s, "C") != 0 && std::strcmp(__s, "POSIX") != 0)

          {

            this->_S_destroy_c_locale(this->_M_c_locale_codecvt);

            this->_S_create_c_locale(this->_M_c_locale_codecvt, __s);

          }

      }

    protected:

      virtual

      ~codecvt_byname() { }

    };

#endif // _CODECVT_H