lib/strnlen.c

   1 /* Find the length of STRING, but scan at most MAXLEN characters.
   2    Copyright (C) 1996, 1997, 1998, 2000, 2001 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #if HAVE_STRING_H
  25 # if !STDC_HEADERS && HAVE_MEMORY_H
  26 #  include <memory.h>
  27 # endif
  28 # include <string.h>
  29 #else
  30 # include <strings.h>
  31 #endif
  32
  33 #ifndef HAVE_DECL_MEMCHR
  34 "this configure-time declaration test was not run"
  35 #endif
  36 #if !HAVE_DECL_MEMCHR
  37 char *memchr ();
  38 #endif
  39
  40 #undef __strnlen
  41 #undef strnlen
  42
  43 #ifndef weak_alias
  44 # define __strnlen strnlen
  45 #endif
  46
  47 /* Find the length of STRING, but scan at most MAXLEN characters.
  48    If no '\0' terminator is found in that many characters, return MAXLEN.  */
  49
  50 size_t
  51 __strnlen (const char *string, size_t maxlen)
  52 {
  53   const char *end = memchr (string, '\0', maxlen);
  54   return end ? (size_t) (end - string) : maxlen;
  55 }
  56 #ifdef weak_alias
  57 weak_alias (__strnlen, strnlen)
  58 #endif