codecvt_specializations.h

俄罗斯高人Mamaich的Pocket gcc编译器（运行在PocketPC上）的全部源代码。

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

// Copyright (C) 2000, 2001, 2002 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// 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
//

// Warning: this file is not meant for user inclusion.  Use <locale>.

// Written by Benjamin Kosnik <[e-mail]>

  // XXX
  // Define this here to codecvt.cc can have _S_max_size definition.
#define _GLIBCPP_USE___ENC_TRAITS 1

  // Extension to use icov for dealing with character encodings,
  // including conversions and comparisons between various character
  // sets.  This object encapsulates data that may need to be shared between
  // char_traits, codecvt and ctype.
  class __enc_traits
  {
  public:
    // Types: 
    // NB: A conversion descriptor subsumes and enhances the
    // functionality of a simple state type such as mbstate_t.
    typedef iconv_t	__desc_type;
    
  protected:
    // Data Members:
    // Max size of charset encoding name
    static const int 	_S_max_size = 32;
    // Name of internal character set encoding.
    char	       	_M_int_enc[_S_max_size];
    // Name of external character set encoding.
    char  	       	_M_ext_enc[_S_max_size];

    // Conversion descriptor between external encoding to internal encoding.
    __desc_type		_M_in_desc;
    // Conversion descriptor between internal encoding to external encoding.
    __desc_type		_M_out_desc;

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

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

  public:
    explicit __enc_traits() 
    : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0) 
    {
      memset(_M_int_enc, 0, _S_max_size);
      memset(_M_ext_enc, 0, _S_max_size);
    }

    explicit __enc_traits(const char* __int, const char* __ext, 
			  int __ibom = 0, int __ebom = 0)
    : _M_in_desc(0), _M_out_desc(0), _M_ext_bom(0), _M_int_bom(0)
    {
      strncpy(_M_int_enc, __int, _S_max_size);
      strncpy(_M_ext_enc, __ext, _S_max_size);
    }

    // 21.1.2 traits typedefs
    // p4
    // typedef STATE_T state_type
    // requires: state_type shall meet the requirements of
    // CopyConstructible types (20.1.3)
    __enc_traits(const __enc_traits& __obj): _M_in_desc(0), _M_out_desc(0)
    {
      strncpy(_M_int_enc, __obj._M_int_enc, _S_max_size);
      strncpy(_M_ext_enc, __obj._M_ext_enc, _S_max_size);
      _M_ext_bom = __obj._M_ext_bom;
      _M_int_bom = __obj._M_int_bom;
    }

    // Need assignment operator as well.
    __enc_traits&
    operator=(const __enc_traits& __obj)
    {
      strncpy(_M_int_enc, __obj._M_int_enc, _S_max_size);
      strncpy(_M_ext_enc, __obj._M_ext_enc, _S_max_size);
      _M_in_desc = 0;
      _M_out_desc = 0;
      _M_ext_bom = __obj._M_ext_bom;
      _M_int_bom = __obj._M_int_bom;
      return *this;
    }

    ~__enc_traits()
    {
      __desc_type __err = reinterpret_cast<iconv_t>(-1);
      if (_M_in_desc && _M_in_desc != __err) 
	iconv_close(_M_in_desc);
      if (_M_out_desc && _M_out_desc != __err) 
	iconv_close(_M_out_desc);
    } 

    void
    _M_init()
    {
      const __desc_type __err = reinterpret_cast<iconv_t>(-1);
      if (!_M_in_desc)
	{
	  _M_in_desc = iconv_open(_M_int_enc, _M_ext_enc);
	  if (_M_in_desc == __err)
	    __throw_runtime_error("creating iconv input descriptor failed.");
	}
      if (!_M_out_desc)
	{
	  _M_out_desc = iconv_open(_M_ext_enc, _M_int_enc);
	  if (_M_out_desc == __err)
	    __throw_runtime_error("creating iconv output descriptor failed.");
	}
    }

    bool
    _M_good()
    { 
      const __desc_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;
    }

    const __desc_type* 
    _M_get_in_descriptor()
    { return &_M_in_desc; }

    const __desc_type* 
    _M_get_out_descriptor()
    { return &_M_out_desc; }

    int 
    _M_get_external_bom()
    { return _M_ext_bom; }

    int 
    _M_get_internal_bom()
    { return _M_int_bom; }

    const char* 
    _M_get_internal_enc()
    { return _M_int_enc; }

    const char* 
    _M_get_external_enc()
    { return _M_ext_enc; }
  };

  // Partial specialization
  // This 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, __enc_traits>
    : public __codecvt_abstract_base<_InternT, _ExternT, __enc_traits>
    {
    public:      
      // Types:
      typedef codecvt_base::result			result;
      typedef _InternT 					intern_type;
      typedef _ExternT 					extern_type;
      typedef __enc_traits 				state_type;
      typedef __enc_traits::__desc_type 		__desc_type;
      typedef __enc_traits				__enc_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(__enc_type* __enc, size_t __refs = 0)
      : __codecvt_abstract_base<intern_type, extern_type, state_type>(__refs)
      { }

    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();