lib/strtok_r.c

/* Reentrant string tokenizer.  Generic version.
   Copyright (C) 1991, 1996-1999, 2001, 2004, 2007, 2009-2026 Free Software
   Foundation, Inc.
   This file is part of the GNU C Library.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <string.h>

#ifdef _LIBC
# undef strtok_r
# undef __strtok_r
#else
# define __strtok_r strtok_r
# define __rawmemchr strchr
#endif

/* Parse S into tokens separated by characters in DELIM.
   If S is NULL, the saved pointer in SAVE_PTR is used as
   the next starting point.  For example:
        char s[] = "-abc-=-def";
        char *sp;
        x = strtok_r(s, "-", &sp);      // x = "abc", sp = "=-def"
        x = strtok_r(NULL, "-=", &sp);  // x = "def", sp = NULL
        x = strtok_r(NULL, "=", &sp);   // x = NULL
                // s = "abc\0-def\0"
*/
char *
__strtok_r (char *s, const char *delim, char **save_ptr)
{
  if (s == NULL)
    s = *save_ptr;

  /* Scan leading delimiters.  */
  s += strspn (s, delim);
  if (*s == '\0')
    {
      *save_ptr = s;
      return NULL;
    }

  /* Find the end of the token.  */
  char *token = s;
  s = strpbrk (token, delim);
  if (s == NULL)
    /* This token finishes the string.  */
    *save_ptr = __rawmemchr (token, '\0');
  else
    {
      /* Terminate the token and make *SAVE_PTR point past it.  */
      *s = '\0';
      *save_ptr = s + 1;
    }
  return token;
}
#ifdef weak_alias
libc_hidden_def (__strtok_r)
weak_alias (__strtok_r, strtok_r)
#endif