// std::codecvt implementation details, generic version -*- C++ -*-
// Copyright (C) 2002-2015 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 3, 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.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
//
// ISO C++ 14882: 22.2.1.5 - Template class codecvt
//
// Written by Benjamin Kosnik <bkoz@redhat.com>
#include <locale>
#include <cstdlib> // For MB_CUR_MAX
#include <climits> // For MB_LEN_MAX
#include <cstring>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// 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;
// The conversion must be done using a temporary destination buffer
// since it is not possible to pass the size of the buffer to wcrtomb
state_type __tmp_state(__state);
// The conversion must be done by calling wcrtomb in a loop rather
// than using wcsrtombs because wcsrtombs assumes that the input is
// zero-terminated.
// Either we can upper bound the total number of external characters to
// something smaller than __to_end - __to or the conversion must be done
// using a temporary destination buffer since it is not possible to
// pass the size of the buffer to wcrtomb
if (MB_CUR_MAX * (__from_end - __from) - (__to_end - __to) <= 0)
while (__from < __from_end)
{
const size_t __conv = wcrtomb(__to, *__from, &__tmp_state);
if (__conv == static_cast<size_t>(-1))
{
__ret = error;
break;
}
__state = __tmp_state;
__to += __conv;
__from++;
}
else
{
extern_type __buf[MB_LEN_MAX];
while (__from < __from_end && __to < __to_end)
{
const size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
if (__conv == static_cast<size_t>(-1))
{
__ret = error;
break;
}
else if (__conv > static_cast<size_t>(__to_end - __to))
{
__ret = partial;
break;
}
memcpy(__to, __buf, __conv);
__state = __tmp_state;
__to += __conv;
__from++;
}
}
if (__ret == ok && __from < __from_end)
__ret = partial;
__from_next = __from;
__to_next = __to;
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 necessary so __state won't be modified
// if [__from, __from_end) is a partial multibyte character.
state_type __tmp_state(__state);
// 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;
}
// 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 (MB_CUR_MAX == 1)
__ret = 1;
return __ret;
}
int
codecvt<wchar_t, char, mbstate_t>::
do_max_length() const throw()
{
// XXX Probably wrong for stateful encodings.
int __ret = MB_CUR_MAX;
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);
while (__from < __end && __max)
{
size_t __conv = mbrtowc(0, __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--;
}
return __ret;
}
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace