codecvt_specializations.h

linux下编程用 编译软件

// 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 <[e-mail]>

/** @file bits/codecvt_specializations.h
 *  This file is a GNU extension to the Standard C++ Library.
 */

  // XXX
  // Define this here so codecvt.cc can have _S_max_size definition.
#define _GLIBCXX_USE_ENCODING_STATE 1

namespace __gnu_cxx
{
  /// @brief  Extension to use icov for dealing with character encodings.
  // This includes conversions and comparisons between various character
  // sets.  This object encapsulates data that may need to be shared between
  // char_traits, codecvt and ctype.
  class encoding_state
  {
  public:
    // Types: 
    // NB: A conversion descriptor subsumes and enhances the
    // functionality of a simple state type such as mbstate_t.
    typedef iconv_t	descriptor_type;
    
  protected:
    // Name of internal character set encoding.
    std::string	       	_M_int_enc;

    // Name of external character set encoding.
    std::string  	_M_ext_enc;

    // Conversion descriptor between external encoding to internal encoding.
    descriptor_type	_M_in_desc;

    // Conversion descriptor between internal encoding to external encoding.
    descriptor_type	_M_out_desc;

    // The byte-order marker for the external encoding, if necessary.
    int			_M_ext_bom;

    // The byte-order marker for the internal encoding, if necessary.
    int			_M_int_bom;

    // Number of external bytes needed to construct one complete
    // character in the internal encoding.
    // NB: -1 indicates variable, or stateful, encodings.
    int 		_M_bytes;

  public:
    explicit 
    encoding_state() 
    : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0), _M_bytes(0)
    { }

    explicit 
    encoding_state(const char* __int, const char* __ext, 
		   int __ibom = 0, int __ebom = 0, int __bytes = 1)
    : _M_int_enc(__int), _M_ext_enc(__ext), _M_in_desc(0), _M_out_desc(0), 
      _M_ext_bom(__ebom), _M_int_bom(__ibom), _M_bytes(__bytes)
    { init(); }

    // 21.1.2 traits typedefs
    // p4
    // typedef STATE_T state_type
    // requires: state_type shall meet the requirements of
    // CopyConstructible types (20.1.3)
    // NB: This does not preseve the actual state of the conversion
    // descriptor member, but it does duplicate the encoding
    // information.
    encoding_state(const encoding_state& __obj) : _M_in_desc(0), _M_out_desc(0)
    { construct(__obj); }

    // Need assignment operator as well.
    encoding_state&
    operator=(const encoding_state& __obj)
    {
      construct(__obj);
      return *this;
    }

    ~encoding_state()
    { destroy(); } 

    bool
    good() const throw()
    { 
      const descriptor_type __err = reinterpret_cast<iconv_t>(-1);
      bool __test = _M_in_desc && _M_in_desc != __err; 
      __test &=  _M_out_desc && _M_out_desc != __err;
      return __test;
    }
    
    int
    character_ratio() const
    { return _M_bytes; }

    const std::string
    internal_encoding() const
    { return _M_int_enc; }

    int 
    internal_bom() const
    { return _M_int_bom; }

    const std::string
    external_encoding() const
    { return _M_ext_enc; }

    int 
    external_bom() const
    { return _M_ext_bom; }

    const descriptor_type&
    in_descriptor() const
    { return _M_in_desc; }

    const descriptor_type&
    out_descriptor() const
    { return _M_out_desc; }

  protected:
    void
    init()
    {
      const descriptor_type __err = reinterpret_cast<iconv_t>(-1);
      const bool __have_encodings = _M_int_enc.size() && _M_ext_enc.size();
      if (!_M_in_desc && __have_encodings)
	{
	  _M_in_desc = iconv_open(_M_int_enc.c_str(), _M_ext_enc.c_str());
	  if (_M_in_desc == __err)
	    std::__throw_runtime_error(__N("encoding_state::_M_init "
				    "creating iconv input descriptor failed"));
	}
      if (!_M_out_desc && __have_encodings)
	{
	  _M_out_desc = iconv_open(_M_ext_enc.c_str(), _M_int_enc.c_str());
	  if (_M_out_desc == __err)
	    std::__throw_runtime_error(__N("encoding_state::_M_init "
				  "creating iconv output descriptor failed"));
	}
    }

    void
    construct(const encoding_state& __obj)
    {
      destroy();
      _M_int_enc = __obj._M_int_enc;
      _M_ext_enc = __obj._M_ext_enc;
      _M_ext_bom = __obj._M_ext_bom;
      _M_int_bom = __obj._M_int_bom;
      _M_bytes = __obj._M_bytes;
      init();
    }

    void
    destroy() throw()
    {
      const descriptor_type __err = reinterpret_cast<iconv_t>(-1);
      if (_M_in_desc && _M_in_desc != __err) 
	{
	  iconv_close(_M_in_desc);
	  _M_in_desc = 0;
	}
      if (_M_out_desc && _M_out_desc != __err) 
	{
	  iconv_close(_M_out_desc);
	  _M_out_desc = 0;
	}
    }
  };

  /// @brief  encoding_char_traits.
  // Custom traits type with encoding_state for the state type, and the
  // associated fpos<encoding_state> for the position type, all other
  // bits equivalent to the required char_traits instantiations.
  template<typename _CharT>
    struct encoding_char_traits : public std::char_traits<_CharT>
    {
      typedef encoding_state				state_type;
      typedef typename std::fpos<state_type>		pos_type;
    };
} // namespace __gnu_cxx

namespace std
{
  using __gnu_cxx::encoding_state;

  /// @brief  codecvt<InternT, _ExternT, encoding_state> specialization.
  // This partial specialization takes advantage of iconv to provide
  // code conversions between a large number of character encodings.
  template<typename _InternT, typename _ExternT>
    class codecvt<_InternT, _ExternT, encoding_state>
    : public __codecvt_abstract_base<_InternT, _ExternT, encoding_state>
    {
    public:      
      // Types:
      typedef codecvt_base::result			result;
      typedef _InternT 					intern_type;
      typedef _ExternT 					extern_type;
      typedef __gnu_cxx::encoding_state 		state_type;
      typedef state_type::descriptor_type 		descriptor_type;

      // Data Members:
      static locale::id 		id;

      explicit 
      codecvt(size_t __refs = 0)
      : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
      { }

      explicit 
      codecvt(state_type& __enc, size_t __refs = 0)
      : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
      { }

     protected:
      virtual 
      ~codecvt() { }