lib/strspn.c

   1 /* Copyright (C) 1991, 1997 Free Software Foundation, Inc.
   2
   3    NOTE: The canonical source of this file is maintained with the GNU
   4    C Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.
   5
   6    This program is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License
   8    as published by the Free Software Foundation; either version 2 of
   9    the License, or (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with this program; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place -
  19    Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 #if HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #if defined _LIBC || HAVE_STRING_H
  26 # include <string.h>
  27 #else
  28 # include <strings.h>
  29 # ifndef strchr
  30 #  define strchr index
  31 # endif
  32 #endif
  33
  34 #undef strspn
  35
  36 /* Return the length of the maximum initial segment
  37    of S which contains only characters in ACCEPT.  */
  38 size_t
  39 strspn (s, accept)
  40      const char *s;
  41      const char *accept;
  42 {
  43   const char *p;
  44   const char *a;
  45   size_t count = 0;
  46
  47   for (p = s; *p != '\0'; ++p)
  48     {
  49       for (a = accept; *a != '\0'; ++a)
  50         if (*p == *a)
  51           break;
  52       if (*a == '\0')
  53         return count;
  54       else
  55         ++count;
  56     }
  57
  58   return count;
  59 }