sysdeps/generic/strtok.c

   1 /* Copyright (C) 1991, 1996, 1997 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <string.h>
  20
  21
  22 static char *olds = NULL;
  23
  24 #undef strtok
  25
  26 /* Parse S into tokens separated by characters in DELIM.
  27    If S is NULL, the last string strtok() was called with is
  28    used.  For example:
  29         char s[] = "-abc-=-def";
  30         x = strtok(s, "-");             // x = "abc"
  31         x = strtok(NULL, "-=");         // x = "def"
  32         x = strtok(NULL, "=");          // x = NULL
  33                 // s = "abc\0-def\0"
  34 */
  35 char *
  36 strtok (s, delim)
  37      char *s;
  38      const char *delim;
  39 {
  40   char *token;
  41
  42   if (s == NULL)
  43     s = olds;
  44
  45   /* Scan leading delimiters.  */
  46   s += strspn (s, delim);
  47   if (*s == '\0')
  48     return NULL;
  49
  50   /* Find the end of the token.  */
  51   token = s;
  52   s = strpbrk (token, delim);
  53   if (s == NULL)
  54     /* This token finishes the string.  */
  55     olds = strchr (token, '\0');
  56   else
  57     {
  58       /* Terminate the token and make OLDS point past it.  */
  59       *s = '\0';
  60       olds = s + 1;
  61     }
  62   return token;
  63 }