sysdeps/generic/strtok.c

   1 /* Copyright (C) 1991, 1996 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
  16 not, 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 /* Parse S into tokens separated by characters in DELIM.
  25    If S is NULL, the last string strtok() was called with is
  26    used.  For example:
  27         char s[] = "-abc-=-def";
  28         x = strtok(s, "-");             // x = "abc"
  29         x = strtok(NULL, "-=");         // x = "def"
  30         x = strtok(NULL, "=");          // x = NULL
  31                 // s = "abc\0-def\0"
  32 */
  33 char *
  34 strtok (s, delim)
  35      char *s;
  36      const char *delim;
  37 {
  38   char *token;
  39
  40   if (s == NULL)
  41     s = olds;
  42
  43   /* Scan leading delimiters.  */
  44   s += strspn (s, delim);
  45   if (*s == '\0')
  46     {
  47       olds = NULL;
  48       return NULL;
  49     }
  50
  51   /* Find the end of the token.  */
  52   token = s;
  53   s = strpbrk (token, delim);
  54   if (s == NULL)
  55     /* This token finishes the string.  */
  56     olds = strchr (token, '\0');
  57   else
  58     {
  59       /* Terminate the token and make OLDS point past it.  */
  60       *s = '\0';
  61       olds = s + 1;
  62     }
  63   return token;
  64 }