compilers/linux86-0.16.17/libc/string/strtok.c

   1 /* Copyright (C) 1991 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., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <string.h>
  20
  21
  22 static char *olds = 0;
  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 register char *s;
  36 register char *delim;
  37 {
  38   char *token;
  39
  40   if (s == 0)
  41     {
  42       if (olds == 0)
  43         {
  44           return 0;
  45         }
  46       else
  47         s = olds;
  48     }
  49
  50   /* Scan leading delimiters.  */
  51   s += strspn(s, delim);
  52   if (*s == '\0')
  53     {
  54       olds = 0;
  55       return 0;
  56     }
  57
  58   /* Find the end of the token.  */
  59   token = s;
  60   s = strpbrk(token, delim);
  61   if (s == 0)
  62     /* This token finishes the string.  */
  63     olds = 0;
  64   else
  65     {
  66       /* Terminate the token and make OLDS point past it.  */
  67       *s = '\0';
  68       olds = s + 1;
  69     }
  70   return token;
  71 }