string/strspn.c

   1 /* Copyright (C) 1991-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <string.h>
  19
  20 #undef strspn
  21 #ifndef STRSPN
  22 #define STRSPN strspn
  23 #endif
  24
  25 /* Return the length of the maximum initial segment
  26    of S which contains only characters in ACCEPT.  */
  27 size_t
  28 STRSPN (const char *s, const char *accept)
  29 {
  30   const char *p;
  31   const char *a;
  32   size_t count = 0;
  33
  34   for (p = s; *p != '\0'; ++p)
  35     {
  36       for (a = accept; *a != '\0'; ++a)
  37         if (*p == *a)
  38           break;
  39       if (*a == '\0')
  40         return count;
  41       else
  42         ++count;
  43     }
  44
  45   return count;
  46 }
  47 libc_hidden_builtin_def (strspn)