gcc/libstdc++-v3/config/locale/gnu/codecvt_members.cc

// std::codecvt implementation details, GNU version -*- C++ -*-

// Copyright (C) 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
//

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

#include <locale>
#include <bits/c++locale_internal.h>

namespace std
{
  // Specializations.
#ifdef _GLIBCXX_USE_WCHAR_T
  codecvt_base::result
  codecvt<wchar_t, char, mbstate_t>::
  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
  {
    result __ret = ok;
    state_type __tmp_state(__state);

#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __c_locale __old = __uselocale(_M_c_locale_codecvt);
#endif

    // wcsnrtombs is *very* fast but stops if encounters NUL characters:
    // in case we fall back to wcrtomb and then continue, in a loop.
    // NB: wcsnrtombs is a GNU extension
    __from_next = __from;
    __to_next = __to;
    while (__from_next < __from_end && __to_next < __to_end
	   && __ret == ok)
      {
	const intern_type* __from_chunk_end = wmemchr(__from_next, L'\0',
						      __from_end - __from_next);
	if (!__from_chunk_end)
	  __from_chunk_end = __from_end;

	const intern_type* __tmp_from = __from_next;
	const size_t __conv = wcsnrtombs(__to_next, &__from_next,
					 __from_chunk_end - __from_next,
					 __to_end - __to_next, &__state);
	if (__conv == static_cast<size_t>(-1))
	  {
	    // In case of error, in order to stop at the exact place we
	    // have to start again from the beginning with a series of
	    // wcrtomb.
	    while (__tmp_from < __from_next)
	      __to_next += wcrtomb(__to_next, *__tmp_from++, &__tmp_state);
	    __state = __tmp_state;	    
	    __ret = error;
	  }
	else if (__from_next && __from_next < __from_chunk_end)
	  {
	    __to_next += __conv;
	    __ret = partial;
	  }
	else
	  {
	    __from_next = __from_chunk_end;
	    __to_next += __conv;
	  }

	if (__from_next < __from_end && __ret == ok)
	  {
	    extern_type __buf[MB_LEN_MAX];
	    __tmp_state = __state;
	    const size_t __conv = wcrtomb(__buf, *__from_next, &__tmp_state);
	    if (__conv == static_cast<size_t>(-1))
	      __ret = error;
	    else if (__conv > static_cast<size_t>(__to_end - __to_next))
	      __ret = partial;
	    else
	      {
		memcpy(__to_next, __buf, __conv);
		__state = __tmp_state;
		__to_next += __conv;
		++__from_next;
	      }
	  }
      }

#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __uselocale(__old);
#endif

    return __ret; 
  }
  
  codecvt_base::result
  codecvt<wchar_t, char, mbstate_t>::
  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
  {
    result __ret = ok;
    // This temporary state object is neccessary so __state won't be modified
    // if [__from, __from_end) is a partial multibyte character.
    state_type __tmp_state(__state);
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __c_locale __old = __uselocale(_M_c_locale_codecvt);
#endif

    // Conversion must be done by calling mbrtowc in a loop rather than
    // by calling mbsrtowcs because mbsrtowcs assumes that the input
    // sequence is zero-terminated.
    while (__from < __from_end && __to < __to_end)
      {
	size_t __conv = mbrtowc(__to, __from, __from_end - __from,
				&__tmp_state);
	if (__conv == static_cast<size_t>(-1))
	  {
	    __ret = error;
	    break;
	  }
	else if (__conv == static_cast<size_t>(-2))
	  {
	    // It is unclear what to return in this case (see DR 382).
	    __ret = partial;
	    break;
	  }
	else if (__conv == 0)
	  {
	    // XXX Probably wrong for stateful encodings
	    __conv = 1;
	    *__to = L'\0';
	  }

	__state = __tmp_state;
	__to++;
	__from += __conv;
      }

#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __uselocale(__old);
#endif

    // It is not clear that __from < __from_end implies __ret != ok
    // (see DR 382).
    if (__ret == ok && __from < __from_end)
      __ret = partial;

    __from_next = __from;
    __to_next = __to;
    return __ret; 
  }

  int 
  codecvt<wchar_t, char, mbstate_t>::
  do_encoding() const throw()
  {
    // XXX This implementation assumes that the encoding is
    // stateless and is either single-byte or variable-width.
    int __ret = 0;
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __c_locale __old = __uselocale(_M_c_locale_codecvt);
#endif
    if (MB_CUR_MAX == 1)
      __ret = 1;
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __uselocale(__old);
#endif
    return __ret;
  }  

  int 
  codecvt<wchar_t, char, mbstate_t>::
  do_max_length() const throw()
  {
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __c_locale __old = __uselocale(_M_c_locale_codecvt);
#endif
    // XXX Probably wrong for stateful encodings.
    int __ret = MB_CUR_MAX;
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __uselocale(__old);
#endif
    return __ret;
  }
  
  int 
  codecvt<wchar_t, char, mbstate_t>::
  do_length(state_type& __state, const extern_type* __from,
	    const extern_type* __end, size_t __max) const
  {
    int __ret = 0;
    state_type __tmp_state(__state);
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __c_locale __old = __uselocale(_M_c_locale_codecvt);
#endif

    while (__from < __end && __max)
      {
	size_t __conv = mbrtowc(NULL, __from, __end - __from, &__tmp_state);
	if (__conv == static_cast<size_t>(-1))
	  {
	    // Invalid source character
	    break;
	  }
	else if (__conv == static_cast<size_t>(-2))
	  {
	    // Remainder of input does not form a complete destination
	    // character.
	    break;
	  }
	else if (__conv == 0)
	  {
	    // XXX Probably wrong for stateful encodings
	    __conv = 1;
	  }

	__state = __tmp_state;
	__from += __conv;
	__ret += __conv;
	__max--;
      }

#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
    __uselocale(__old);
#endif
    return __ret; 
  }
#endif
}