/* Copyright (C) 1991-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <string.h>

#include <memcopy.h>

#undef strncmp

#ifndef STRNCMP

#define STRNCMP strncmp

#endif

/* Compare no more than N characters of S1 and S2,

   returning less than, equal to or greater than zero

   if S1 is lexicographically less than, equal to or

   greater than S2.  */

int

STRNCMP (const char *s1, const char *s2, size_t n)

{

  unsigned char c1 = '\0';

  unsigned char c2 = '\0';

  if (n >= 4)

    {

      size_t n4 = n >> 2;

      do

	{

	  c1 = (unsigned char) *s1++;

	  c2 = (unsigned char) *s2++;

	  if (c1 == '\0' || c1 != c2)

	    return c1 - c2;

	  c1 = (unsigned char) *s1++;

	  c2 = (unsigned char) *s2++;

	  if (c1 == '\0' || c1 != c2)

	    return c1 - c2;

	  c1 = (unsigned char) *s1++;

	  c2 = (unsigned char) *s2++;

	  if (c1 == '\0' || c1 != c2)

	    return c1 - c2;

	  c1 = (unsigned char) *s1++;

	  c2 = (unsigned char) *s2++;

	  if (c1 == '\0' || c1 != c2)

	    return c1 - c2;

	} while (--n4 > 0);

      n &= 3;

    }

  while (n > 0)

    {

      c1 = (unsigned char) *s1++;

      c2 = (unsigned char) *s2++;

      if (c1 == '\0' || c1 != c2)

	return c1 - c2;

      n--;

    }

  return c1 - c2;

}

libc_hidden_builtin_def (STRNCMP)