lib/wcswidth-impl.h

   1 /* Determine number of screen columns needed for a size-bounded wide string.
   2    Copyright (C) 1999, 2011-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 1999.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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
  13    GNU 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 int
  19 FUNC (const UNIT *s, size_t n)
  20 {
  21   int count = 0;
  22   for (; n > 0; s++, n--)
  23     {
  24       UNIT c = *s;
  25       if (c == (UNIT)'\0')
  26         break;
  27       {
  28         int width = CHARACTER_WIDTH (c);
  29         if (width < 0)
  30           goto found_nonprinting;
  31         if (width > INT_MAX - count)
  32           goto overflow;
  33         count += width;
  34       }
  35     }
  36   return count;
  37
  38   /* The total width has become > INT_MAX.
  39      Continue searching for a non-printing wide character.  */
  40   for (; n > 0; s++, n--)
  41     {
  42       UNIT c = *s;
  43       if (c == (UNIT)'\0')
  44         break;
  45       {
  46         int width = CHARACTER_WIDTH (c);
  47         if (width < 0)
  48           goto found_nonprinting;
  49       }
  50      overflow: ;
  51     }
  52   return INT_MAX;
  53
  54  found_nonprinting:
  55   return -1;
  56 }