libstdc++-v3/config/locale/generic/codecvt_members.cc

   1 // std::codecvt implementation details, generic version -*- C++ -*-
   2
   3 // Copyright (C) 2002-2013 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 //
  26 // ISO C++ 14882: 22.2.1.5 - Template class codecvt
  27 //
  28
  29 // Written by Benjamin Kosnik <bkoz@redhat.com>
  30
  31 #include <locale>
  32 #include <cstdlib>  // For MB_CUR_MAX
  33 #include <climits>  // For MB_LEN_MAX
  34 #include <cstring>
  35
  36 namespace std _GLIBCXX_VISIBILITY(default)
  37 {
  38 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  39
  40   // Specializations.
  41 #ifdef _GLIBCXX_USE_WCHAR_T
  42   codecvt_base::result
  43   codecvt<wchar_t, char, mbstate_t>::
  44   do_out(state_type& __state, const intern_type* __from,
  45          const intern_type* __from_end, const intern_type*& __from_next,
  46          extern_type* __to, extern_type* __to_end,
  47          extern_type*& __to_next) const
  48   {
  49     result __ret = ok;
  50     // The conversion must be done using a temporary destination buffer
  51     // since it is not possible to pass the size of the buffer to wcrtomb
  52     state_type __tmp_state(__state);
  53
  54     // The conversion must be done by calling wcrtomb in a loop rather
  55     // than using wcsrtombs because wcsrtombs assumes that the input is
  56     // zero-terminated.
  57
  58     // Either we can upper bound the total number of external characters to
  59     // something smaller than __to_end - __to or the conversion must be done
  60     // using a temporary destination buffer since it is not possible to
  61     // pass the size of the buffer to wcrtomb
  62     if (MB_CUR_MAX * (__from_end - __from) - (__to_end - __to) <= 0)
  63       while (__from < __from_end)
  64         {
  65           const size_t __conv = wcrtomb(__to, *__from, &__tmp_state);
  66           if (__conv == static_cast<size_t>(-1))
  67             {
  68               __ret = error;
  69               break;
  70             }
  71           __state = __tmp_state;
  72           __to += __conv;
  73           __from++;
  74         }
  75     else
  76       {
  77         extern_type __buf[MB_LEN_MAX];
  78         while (__from < __from_end && __to < __to_end)
  79           {
  80             const size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
  81             if (__conv == static_cast<size_t>(-1))
  82               {
  83                 __ret = error;
  84                 break;
  85               }
  86             else if (__conv > static_cast<size_t>(__to_end - __to))
  87               {
  88                 __ret = partial;
  89                 break;
  90               }
  91
  92             memcpy(__to, __buf, __conv);
  93             __state = __tmp_state;
  94             __to += __conv;
  95             __from++;
  96           }
  97       }
  98
  99     if (__ret == ok && __from < __from_end)
 100       __ret = partial;
 101
 102     __from_next = __from;
 103     __to_next = __to;
 104     return __ret;
 105   }
 106
 107   codecvt_base::result
 108   codecvt<wchar_t, char, mbstate_t>::
 109   do_in(state_type& __state, const extern_type* __from,
 110         const extern_type* __from_end, const extern_type*& __from_next,
 111         intern_type* __to, intern_type* __to_end,
 112         intern_type*& __to_next) const
 113   {
 114     result __ret = ok;
 115     // This temporary state object is neccessary so __state won't be modified
 116     // if [__from, __from_end) is a partial multibyte character.
 117     state_type __tmp_state(__state);
 118
 119     // Conversion must be done by calling mbrtowc in a loop rather than
 120     // by calling mbsrtowcs because mbsrtowcs assumes that the input
 121     // sequence is zero-terminated.
 122     while (__from < __from_end && __to < __to_end)
 123       {
 124         size_t __conv = mbrtowc(__to, __from, __from_end - __from,
 125                                 &__tmp_state);
 126         if (__conv == static_cast<size_t>(-1))
 127           {
 128             __ret = error;
 129             break;
 130           }
 131         else if (__conv == static_cast<size_t>(-2))
 132           {
 133             // It is unclear what to return in this case (see DR 382).
 134             __ret = partial;
 135             break;
 136           }
 137         else if (__conv == 0)
 138           {
 139             // XXX Probably wrong for stateful encodings
 140             __conv = 1;
 141             *__to = L'\0';
 142           }
 143
 144         __state = __tmp_state;
 145         __to++;
 146         __from += __conv;
 147       }
 148
 149     // It is not clear that __from < __from_end implies __ret != ok
 150     // (see DR 382).
 151     if (__ret == ok && __from < __from_end)
 152       __ret = partial;
 153
 154     __from_next = __from;
 155     __to_next = __to;
 156     return __ret;
 157   }
 158
 159   int
 160   codecvt<wchar_t, char, mbstate_t>::
 161   do_encoding() const throw()
 162   {
 163     // XXX This implementation assumes that the encoding is
 164     // stateless and is either single-byte or variable-width.
 165     int __ret = 0;
 166     if (MB_CUR_MAX == 1)
 167       __ret = 1;
 168     return __ret;
 169   }
 170
 171   int
 172   codecvt<wchar_t, char, mbstate_t>::
 173   do_max_length() const throw()
 174   {
 175     // XXX Probably wrong for stateful encodings.
 176     int __ret = MB_CUR_MAX;
 177     return __ret;
 178   }
 179
 180   int
 181   codecvt<wchar_t, char, mbstate_t>::
 182   do_length(state_type& __state, const extern_type* __from,
 183             const extern_type* __end, size_t __max) const
 184   {
 185     int __ret = 0;
 186     state_type __tmp_state(__state);
 187
 188     while (__from < __end && __max)
 189       {
 190         size_t __conv = mbrtowc(0, __from, __end - __from, &__tmp_state);
 191         if (__conv == static_cast<size_t>(-1))
 192           {
 193             // Invalid source character
 194             break;
 195           }
 196         else if (__conv == static_cast<size_t>(-2))
 197           {
 198             // Remainder of input does not form a complete destination
 199             // character.
 200             break;
 201           }
 202         else if (__conv == 0)
 203           {
 204             // XXX Probably wrong for stateful encodings
 205             __conv = 1;
 206           }
 207
 208         __state = __tmp_state;
 209         __from += __conv;
 210         __ret += __conv;
 211         __max--;
 212       }
 213
 214     return __ret;
 215   }
 216 #endif
 217
 218 _GLIBCXX_END_NAMESPACE_VERSION
 219 } // namespace