memmove.c

来自「QNX ADS BSP code for i.MX27 chips」· C语言 代码 · 共 49 行

/*
 * $QNXLicenseC: 
 * Copyright 2007, QNX Software Systems.  
 *  
 * Licensed under the Apache License, Version 2.0 (the "License"). You  
 * may not reproduce, modify or distribute this software except in  
 * compliance with the License. You may obtain a copy of the License  
 * at: http://www.apache.org/licenses/LICENSE-2.0  
 *  
 * Unless required by applicable law or agreed to in writing, software  
 * distributed under the License is distributed on an "AS IS" basis,  
 * WITHOUT WARRANTIES OF ANY KIND, either express or implied. 
 * 
 * This file may contain contributions from others, either as  
 * contributors under the License or as licensors under other terms.   
 * Please review this entire file for other proprietary rights or license  
 * notices, as well as the QNX Development Suite License Guide at  
 * http://licensing.qnx.com/license-guide/ for other information. 
 * $
 */

 
 #include <string.h>

void *
memmove( void *dest, const void *src, size_t len ) {
	char		*d = dest;
	const char	*s = src;

	if( s < d && (s+len) > d ) {
		/* pointers overlapping, have to copy backwards */
		for( ;; ) {
			--len;
			if( len == (size_t)-1 ) break;
			d[len] = s[len];
		}
	} else {

	/*
     *	use optimized memcpy (duff's device based)
	 */	
     
		memcpy(dest,src,len);
	
	}
	return( dest );
}