stdio-common/translated_number_width.c

   1 /* Compute the printf width of a sequence of ASCII digits.
   2    Copyright (C) 2022-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <limits.h>
  21 #include <locale/localeinfo.h>
  22 #include <printf.h>
  23
  24 int
  25 __translated_number_width (locale_t loc, const char *first, const char *last)
  26 {
  27   struct lc_ctype_data *ctype = loc->__locales[LC_CTYPE]->private;
  28
  29   if (ctype->outdigit_bytes_all_equal > 0)
  30     return (last - first) * ctype->outdigit_bytes_all_equal;
  31   else
  32     {
  33       /* Digits have varying length, so the fast path cannot be used.  */
  34       int digits = 0;
  35       for (const char *p = first; p < last; ++p)
  36         {
  37           assert ('0' <= *p && *p <= '9');
  38           digits += ctype->outdigit_bytes[*p - '0'];
  39         }
  40       return digits;
  41     }
  42 }