string/strtok.c

   1 /* Copyright (C) 1991-2015 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 #ifndef STRTOK
  26 # define STRTOK strtok
  27 #endif
  28
  29 /* Parse S into tokens separated by characters in DELIM.
  30    If S is NULL, the last string strtok() was called with is
  31    used.  For example:
  32         char s[] = "-abc-=-def";
  33         x = strtok(s, "-");             // x = "abc"
  34         x = strtok(NULL, "-=");         // x = "def"
  35         x = strtok(NULL, "=");          // x = NULL
  36                 // s = "abc\0=-def\0"
  37 */
  38 char *
  39 STRTOK (char *s, const char *delim)
  40 {
  41   char *token;
  42
  43   if (s == NULL)
  44     s = olds;
  45
  46   /* Scan leading delimiters.  */
  47   s += strspn (s, delim);
  48   if (*s == '\0')
  49     {
  50       olds = s;
  51       return NULL;
  52     }
  53
  54   /* Find the end of the token.  */
  55   token = s;
  56   s = strpbrk (token, delim);
  57   if (s == NULL)
  58     /* This token finishes the string.  */
  59     olds = __rawmemchr (token, '\0');
  60   else
  61     {
  62       /* Terminate the token and make OLDS point past it.  */
  63       *s = '\0';
  64       olds = s + 1;
  65     }
  66   return token;
  67 }