text: /* Convert multibyte character to wide character.
     Copyright (C) 1999-2002, 2005-2020 Free Software Foundation, Inc.
  
     This program 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 of the License, or
     (at your option) any later version.
  
     This program 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 program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  /* Written by Bruno Haible <bruno@clisp.org>, 2008.  */
  
  /* This file contains the part of the body of the mbrtowc and mbrtoc32 functions
     that handles the special case of the UTF-8 encoding.  */
  
          /* Cf. unistr/u8-mbtouc.c.  */
          unsigned char c = (unsigned char) p[0];
  
          if (c < 0x80)
            {
              if (pwc != NULL)
                *pwc = c;
              res = (c == 0 ? 0 : 1);
              goto success;
            }
          if (c >= 0xc2)
            {
              if (c < 0xe0)
                {
                  if (m == 1)
                    goto incomplete;
                  else /* m >= 2 */
                    {
                      unsigned char c2 = (unsigned char) p[1];
  
                      if ((c2 ^ 0x80) < 0x40)
                        {
                          if (pwc != NULL)
                            *pwc = ((unsigned int) (c & 0x1f) << 6)
                                   | (unsigned int) (c2 ^ 0x80);
                          res = 2;
                          goto success;
                        }
                    }
                }
              else if (c < 0xf0)
                {
                  if (m == 1)
                    goto incomplete;
                  else
                    {
                      unsigned char c2 = (unsigned char) p[1];
  
                      if ((c2 ^ 0x80) < 0x40
                          && (c >= 0xe1 || c2 >= 0xa0)
                          && (c != 0xed || c2 < 0xa0))
                        {
                          if (m == 2)
                            goto incomplete;
                          else /* m >= 3 */
                            {
                              unsigned char c3 = (unsigned char) p[2];
  
                              if ((c3 ^ 0x80) < 0x40)
                                {
                                  unsigned int wc =
                                    (((unsigned int) (c & 0x0f) << 12)
                                     | ((unsigned int) (c2 ^ 0x80) << 6)
                                     | (unsigned int) (c3 ^ 0x80));
  
                                  if (FITS_IN_CHAR_TYPE (wc))
                                    {
                                      if (pwc != NULL)
                                        *pwc = wc;
                                      res = 3;
                                      goto success;
                                    }
                                }
                            }
                        }
                    }
                }
              else if (c <= 0xf4)
                {
                  if (m == 1)
                    goto incomplete;
                  else
                    {
                      unsigned char c2 = (unsigned char) p[1];
  
                      if ((c2 ^ 0x80) < 0x40
                          && (c >= 0xf1 || c2 >= 0x90)
                          && (c < 0xf4 || (c == 0xf4 && c2 < 0x90)))
                        {
                          if (m == 2)
                            goto incomplete;
                          else
                            {
                              unsigned char c3 = (unsigned char) p[2];
  
                              if ((c3 ^ 0x80) < 0x40)
                                {
                                  if (m == 3)
                                    goto incomplete;
                                  else /* m >= 4 */
                                    {
                                      unsigned char c4 = (unsigned char) p[3];
  
                                      if ((c4 ^ 0x80) < 0x40)
                                        {
                                          unsigned int wc =
                                            (((unsigned int) (c & 0x07) << 18)
                                             | ((unsigned int) (c2 ^ 0x80) << 12)
                                             | ((unsigned int) (c3 ^ 0x80) << 6)
                                             | (unsigned int) (c4 ^ 0x80));
  
                                          if (FITS_IN_CHAR_TYPE (wc))
                                            {
                                              if (pwc != NULL)
                                                *pwc = wc;
                                              res = 4;
                                              goto success;
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
          goto invalid;
  