string/strtok_r.c

   1 /* Reentrant string tokenizer.  Generic version.
   2    Copyright (C) 1991,1996-1999,2001,2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <string.h>
  25
  26 #undef strtok_r
  27 #undef __strtok_r
  28
  29 #ifndef _LIBC
  30 /* Get specification.  */
  31 # include "strtok_r.h"
  32 # define __strtok_r strtok_r
  33 # define __rawmemchr strchr
  34 #endif
  35
  36 /* Parse S into tokens separated by characters in DELIM.
  37    If S is NULL, the saved pointer in SAVE_PTR is used as
  38    the next starting point.  For example:
  39         char s[] = "-abc-=-def";
  40         char *sp;
  41         x = strtok_r(s, "-", &sp);      // x = "abc", sp = "=-def"
  42         x = strtok_r(NULL, "-=", &sp);  // x = "def", sp = NULL
  43         x = strtok_r(NULL, "=", &sp);   // x = NULL
  44                 // s = "abc\0-def\0"
  45 */
  46 char *
  47 __strtok_r (char *s, const char *delim, char **save_ptr)
  48 {
  49   char *token;
  50
  51   if (s == NULL)
  52     s = *save_ptr;
  53
  54   /* Scan leading delimiters.  */
  55   s += strspn (s, delim);
  56   if (*s == '\0')
  57     {
  58       *save_ptr = s;
  59       return NULL;
  60     }
  61
  62   /* Find the end of the token.  */
  63   token = s;
  64   s = strpbrk (token, delim);
  65   if (s == NULL)
  66     /* This token finishes the string.  */
  67     *save_ptr = __rawmemchr (token, '\0');
  68   else
  69     {
  70       /* Terminate the token and make *SAVE_PTR point past it.  */
  71       *s = '\0';
  72       *save_ptr = s + 1;
  73     }
  74   return token;
  75 }
  76 #ifdef weak_alias
  77 libc_hidden_def (__strtok_r)
  78 weak_alias (__strtok_r, strtok_r)
  79 #endif