memcmp.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

// 
//  Visopsys
//  Copyright (C) 1998-2007 J. Andrew McLaughlin
//  
//  This 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.
//
//  This 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 this library; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//  memcmp.c
//

// This is the standard "memcmp" function, as found in standard C libraries

#include <string.h>


int memcmp(const void *first, const void *second, size_t length)
{
  size_t count;

  // We loop through the bytes making sure they match.  If "length" bytes
  // match, we return 0.  Otherwise, we return whether the byte from 'first'
  // is less than or greater than the byte from 'second'.

  for (count = 0; count < length; count ++)
    if (((unsigned char *) first)[count] != ((unsigned char *) second)[count])
      {
	if (((unsigned char *) first)[count] <
	    ((unsigned char *) second)[count])
	  return (-1);
	else
	  return (1);
      }		
  
  // If we fall through to here, we matched.
  return (0);
}