1  /* Count characters in UTF-8 string.
       2     Copyright (C) 2007, 2009-2023 Free Software Foundation, Inc.
       3     Written by Bruno Haible <bruno@clisp.org>, 2007.
       4  
       5     This file is free software.
       6     It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
       7     You can redistribute it and/or modify it under either
       8       - the terms of the GNU Lesser General Public License as published
       9         by the Free Software Foundation, either version 3, or (at your
      10         option) any later version, or
      11       - the terms of the GNU General Public License as published by the
      12         Free Software Foundation; either version 2, or (at your option)
      13         any later version, or
      14       - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
      15  
      16     This file is distributed in the hope that it will be useful,
      17     but WITHOUT ANY WARRANTY; without even the implied warranty of
      18     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      19     Lesser General Public License and the GNU General Public License
      20     for more details.
      21  
      22     You should have received a copy of the GNU Lesser General Public
      23     License and of the GNU General Public License along with this
      24     program.  If not, see <https://www.gnu.org/licenses/>.  */
      25  
      26  #include <config.h>
      27  
      28  /* Specification.  */
      29  #include "unistr.h"
      30  
      31  size_t
      32  u8_mbsnlen (const uint8_t *s, size_t n)
      33  {
      34    size_t characters;
      35  
      36    characters = 0;
      37    while (n > 0)
      38      {
      39        ucs4_t uc;
      40        int count = u8_mbtoucr (&uc, s, n);
      41        characters++;
      42        if (count == -2)
      43          break;
      44        if (count < 0)
      45          count = u8_mbtouc (&uc, s, n);
      46        else if (count == 0)
      47          count = 1;
      48        s += count;
      49        n -= count;
      50      }
      51    return characters;
      52  }