sysdeps/generic/strsep.c

   1 /* Copyright (C) 1992, 1993, 1996, 1997 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <string.h>
  20
  21 #undef strsep
  22
  23 char *
  24 __strsep (char **stringp, const char *delim)
  25 {
  26   char *begin, *end;
  27
  28   begin = *stringp;
  29   if (! begin || *begin == '\0')
  30     return NULL;
  31
  32   /* A frequent case is when the delimiter string contains only one
  33      character.  Here we don't need to call the expensive `strpbrk'
  34      function and instead work using `strchr'.  */
  35   if (delim[0] == '\0' || delim[1] == '\0')
  36     {
  37       char ch = delim[0];
  38
  39       if (ch == '\0')
  40         end = NULL;
  41       else
  42         {
  43           while (*begin == ch)
  44             ++begin;
  45
  46           end = strchr (begin, delim[0]);
  47         }
  48     }
  49   else
  50     /* Find the end of the token.  */
  51     end = strpbrk (begin, delim);
  52
  53   if (end)
  54     {
  55       /* Terminate the token and set *STRINGP past NUL character.  */
  56       *end++ = '\0';
  57       *stringp = end;
  58     }
  59   else
  60     /* No more delimiters; this is the last token.  */
  61     *stringp = NULL;
  62
  63   return begin;
  64 }
  65 weak_alias (__strsep, strsep)