lib/uniwidth/u8-width.c

   1 /* Determine display width of UTF-8 string.
   2    Copyright (C) 2001-2002, 2006-2007, 2009-2018 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2002.
   4
   5    This program is free software: you can redistribute it and/or modify it
   6    under the terms of the GNU Lesser General Public License as published
   7    by the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include "uniwidth.h"
  22
  23 #include "unistr.h"
  24
  25 int
  26 u8_width (const uint8_t *s, size_t n, const char *encoding)
  27 {
  28   const uint8_t *s_end = s + n;
  29   int width = 0;
  30
  31   while (s < s_end)
  32     {
  33       ucs4_t uc;
  34       int w;
  35
  36       s += u8_mbtouc_unsafe (&uc, s, s_end - s);
  37
  38       if (uc == 0)
  39         break; /* end of string reached */
  40
  41       w = uc_width (uc, encoding);
  42       if (w >= 0) /* ignore control characters in the string */
  43         width += w;
  44     }
  45
  46   return width;
  47 }