glibc/wcsmbs/wmemcmp.c

/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include <wchar.h>


int
wmemcmp (s1, s2, n)
     const wchar_t *s1;
     const wchar_t *s2;
     size_t n;
{
  register wint_t c1;
  register wint_t c2;

  while (n >= 4)
    {
      c1 = (wint_t) s1[0];
      c2 = (wint_t) s2[0];
      if (c1 - c2 != 0)
	return c1 - c2;
      c1 = (wint_t) s1[1];
      c2 = (wint_t) s2[1];
      if (c1 - c2 != 0)
	return c1 - c2;
      c1 = (wint_t) s1[2];
      c2 = (wint_t) s2[2];
      if (c1 - c2 != 0)
	return c1 - c2;
      c1 = (wint_t) s1[3];
      c2 = (wint_t) s2[3];
      if (c1 - c2 != 0)
	return c1 - c2;
      s1 += 4;
      s2 += 4;
      n -= 4;
    }

  if (n > 0)
    {
      c1 = (wint_t) s1[0];
      c2 = (wint_t) s2[0];
      if (c1 - c2 != 0)
	return c1 - c2;
      ++s1;
      ++s2;
      --n;
    }
  if (n > 0)
    {
      c1 = (wint_t) s1[0];
      c2 = (wint_t) s2[0];
      if (c1 - c2 != 0)
	return c1 - c2;
      ++s1;
      ++s2;
      --n;
    }
  if (n > 0)
    {
      c1 = (wint_t) s1[0];
      c2 = (wint_t) s2[0];
      if (c1 - c2 != 0)
	return c1 - c2;
    }

  return 0;
}