sysdeps/generic/strsep.c

   1 /* Copyright (C) 1992, 1993, 1996, 1997, 1998 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 #undef strsep
  23
  24 char *
  25 __strsep (char **stringp, const char *delim)
  26 {
  27   char *begin, *end;
  28
  29   begin = *stringp;
  30   if (begin == NULL)
  31     return NULL;
  32
  33   /* A frequent case is when the delimiter string contains only one
  34      character.  Here we don't need to call the expensive `strpbrk'
  35      function and instead work using `strchr'.  */
  36   if (delim[0] == '\0' || delim[1] == '\0')
  37     {
  38       char ch = delim[0];
  39
  40       if (ch == '\0')
  41         end = NULL;
  42       else
  43         {
  44           if (*begin == ch)
  45             end = begin;
  46           else
  47             end = strchr (begin + 1, ch);
  48         }
  49     }
  50   else
  51     /* Find the end of the token.  */
  52     end = strpbrk (begin, delim);
  53
  54   if (end)
  55     {
  56       /* Terminate the token and set *STRINGP past NUL character.  */
  57       *end++ = '\0';
  58       *stringp = end;
  59     }
  60   else
  61     /* No more delimiters; this is the last token.  */
  62     *stringp = NULL;
  63
  64   return begin;
  65 }
  66 weak_alias (__strsep, strsep)