lib/strnlen.c

   1 /* Find the length of STRING, but scan at most MAXLEN characters.
   2    Copyright (C) 1996, 1997, 1998, 2000-2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 #if HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #if HAVE_STRING_H
  24 # if !STDC_HEADERS && HAVE_MEMORY_H
  25 #  include <memory.h>
  26 # endif
  27 /* Temporarily redefine strnlen so that an inconsistent prototype
  28    (on at least AIX4.3.2.0 w/gcc-2.95.3) doesn't cause trouble.  */
  29 # define strnlen system_strnlen
  30 # include <string.h>
  31 # undef strnlen
  32 #else
  33 # include <strings.h>
  34 #endif
  35
  36 #ifndef HAVE_DECL_MEMCHR
  37 "this configure-time declaration test was not run"
  38 #endif
  39 #if !HAVE_DECL_MEMCHR
  40 char *memchr ();
  41 #endif
  42
  43 #undef __strnlen
  44 #undef strnlen
  45
  46 #ifndef weak_alias
  47 # define __strnlen strnlen
  48 #endif
  49
  50 /* Find the length of STRING, but scan at most MAXLEN characters.
  51    If no '\0' terminator is found in that many characters, return MAXLEN.  */
  52
  53 size_t
  54 __strnlen (const char *string, size_t maxlen)
  55 {
  56   const char *end = memchr (string, '\0', maxlen);
  57   return end ? (size_t) (end - string) : maxlen;
  58 }
  59 #ifdef weak_alias
  60 weak_alias (__strnlen, strnlen)
  61 #endif