string/strtok.c

   1 /* Copyright (C) 1991-2013 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
  21 static char *olds;
  22
  23 #undef strtok
  24
  25 /* Parse S into tokens separated by characters in DELIM.
  26    If S is NULL, the last string strtok() was called with is
  27    used.  For example:
  28         char s[] = "-abc-=-def";
  29         x = strtok(s, "-");             // x = "abc"
  30         x = strtok(NULL, "-=");         // x = "def"
  31         x = strtok(NULL, "=");          // x = NULL
  32                 // s = "abc\0=-def\0"
  33 */
  34 char *
  35 strtok (s, delim)
  36      char *s;
  37      const char *delim;
  38 {
  39   char *token;
  40
  41   if (s == NULL)
  42     s = olds;
  43
  44   /* Scan leading delimiters.  */
  45   s += strspn (s, delim);
  46   if (*s == '\0')
  47     {
  48       olds = s;
  49       return NULL;
  50     }
  51
  52   /* Find the end of the token.  */
  53   token = s;
  54   s = strpbrk (token, delim);
  55   if (s == NULL)
  56     /* This token finishes the string.  */
  57     olds = __rawmemchr (token, '\0');
  58   else
  59     {
  60       /* Terminate the token and make OLDS point past it.  */
  61       *s = '\0';
  62       olds = s + 1;
  63     }
  64   return token;
  65 }