1  /* Convert multibyte character to wide character.
       2     Copyright (C) 1999-2002, 2005-2023 Free Software Foundation, Inc.
       3  
       4     This file is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU Lesser General Public License as
       6     published by the Free Software Foundation; either version 2.1 of the
       7     License, or (at your option) any later version.
       8  
       9     This file is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Bruno Haible <bruno@clisp.org>, 2008.  */
      18  
      19  /* This file contains the part of the body of the mbrtowc and mbrtoc32 functions
      20     that handles the special case of the UTF-8 encoding.  */
      21  
      22          /* Cf. unistr/u8-mbtouc.c.  */
      23          unsigned char c = (unsigned char) p[0];
      24  
      25          if (c < 0x80)
      26            {
      27              if (pwc != NULL)
      28                *pwc = c;
      29              res = (c == 0 ? 0 : 1);
      30              goto success;
      31            }
      32          if (c >= 0xc2)
      33            {
      34              if (c < 0xe0)
      35                {
      36                  if (m == 1)
      37                    goto incomplete;
      38                  else /* m >= 2 */
      39                    {
      40                      unsigned char c2 = (unsigned char) p[1];
      41  
      42                      if ((c2 ^ 0x80) < 0x40)
      43                        {
      44                          if (pwc != NULL)
      45                            *pwc = ((unsigned int) (c & 0x1f) << 6)
      46                                   | (unsigned int) (c2 ^ 0x80);
      47                          res = 2;
      48                          goto success;
      49                        }
      50                    }
      51                }
      52              else if (c < 0xf0)
      53                {
      54                  if (m == 1)
      55                    goto incomplete;
      56                  else
      57                    {
      58                      unsigned char c2 = (unsigned char) p[1];
      59  
      60                      if ((c2 ^ 0x80) < 0x40
      61                          && (c >= 0xe1 || c2 >= 0xa0)
      62                          && (c != 0xed || c2 < 0xa0))
      63                        {
      64                          if (m == 2)
      65                            goto incomplete;
      66                          else /* m >= 3 */
      67                            {
      68                              unsigned char c3 = (unsigned char) p[2];
      69  
      70                              if ((c3 ^ 0x80) < 0x40)
      71                                {
      72                                  unsigned int wc =
      73                                    (((unsigned int) (c & 0x0f) << 12)
      74                                     | ((unsigned int) (c2 ^ 0x80) << 6)
      75                                     | (unsigned int) (c3 ^ 0x80));
      76  
      77                                  if (FITS_IN_CHAR_TYPE (wc))
      78                                    {
      79                                      if (pwc != NULL)
      80                                        *pwc = wc;
      81                                      res = 3;
      82                                      goto success;
      83                                    }
      84                                }
      85                            }
      86                        }
      87                    }
      88                }
      89              else if (c <= 0xf4)
      90                {
      91                  if (m == 1)
      92                    goto incomplete;
      93                  else
      94                    {
      95                      unsigned char c2 = (unsigned char) p[1];
      96  
      97                      if ((c2 ^ 0x80) < 0x40
      98                          && (c >= 0xf1 || c2 >= 0x90)
      99                          && (c < 0xf4 || (/* c == 0xf4 && */ c2 < 0x90)))
     100                        {
     101                          if (m == 2)
     102                            goto incomplete;
     103                          else
     104                            {
     105                              unsigned char c3 = (unsigned char) p[2];
     106  
     107                              if ((c3 ^ 0x80) < 0x40)
     108                                {
     109                                  if (m == 3)
     110                                    goto incomplete;
     111                                  else /* m >= 4 */
     112                                    {
     113                                      unsigned char c4 = (unsigned char) p[3];
     114  
     115                                      if ((c4 ^ 0x80) < 0x40)
     116                                        {
     117                                          unsigned int wc =
     118                                            (((unsigned int) (c & 0x07) << 18)
     119                                             | ((unsigned int) (c2 ^ 0x80) << 12)
     120                                             | ((unsigned int) (c3 ^ 0x80) << 6)
     121                                             | (unsigned int) (c4 ^ 0x80));
     122  
     123                                          if (FITS_IN_CHAR_TYPE (wc))
     124                                            {
     125                                              if (pwc != NULL)
     126                                                *pwc = wc;
     127                                              res = 4;
     128                                              goto success;
     129                                            }
     130                                        }
     131                                    }
     132                                }
     133                            }
     134                        }
     135                    }
     136                }
     137            }
     138          goto invalid;