string/strtok_r.c

   1 /* Reentrant string tokenizer.  Generic version.
   2    Copyright (C) 1991-2016 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifdef HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #include <string.h>
  24
  25 #undef strtok_r
  26 #undef __strtok_r
  27
  28 #ifndef _LIBC
  29 /* Get specification.  */
  30 # include "strtok_r.h"
  31 # define __strtok_r strtok_r
  32 # define __rawmemchr strchr
  33 #endif
  34
  35 /* Parse S into tokens separated by characters in DELIM.
  36    If S is NULL, the saved pointer in SAVE_PTR is used as
  37    the next starting point.  For example:
  38         char s[] = "-abc-=-def";
  39         char *sp;
  40         x = strtok_r(s, "-", &sp);      // x = "abc", sp = "=-def"
  41         x = strtok_r(NULL, "-=", &sp);  // x = "def", sp = NULL
  42         x = strtok_r(NULL, "=", &sp);   // x = NULL
  43                 // s = "abc\0-def\0"
  44 */
  45 char *
  46 __strtok_r (char *s, const char *delim, char **save_ptr)
  47 {
  48   char *token;
  49
  50   if (s == NULL)
  51     s = *save_ptr;
  52
  53   /* Scan leading delimiters.  */
  54   s += strspn (s, delim);
  55   if (*s == '\0')
  56     {
  57       *save_ptr = s;
  58       return NULL;
  59     }
  60
  61   /* Find the end of the token.  */
  62   token = s;
  63   s = strpbrk (token, delim);
  64   if (s == NULL)
  65     /* This token finishes the string.  */
  66     *save_ptr = __rawmemchr (token, '\0');
  67   else
  68     {
  69       /* Terminate the token and make *SAVE_PTR point past it.  */
  70       *s = '\0';
  71       *save_ptr = s + 1;
  72     }
  73   return token;
  74 }
  75 #ifdef weak_alias
  76 libc_hidden_def (__strtok_r)
  77 weak_alias (__strtok_r, strtok_r)
  78 #endif