/* * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009 * The President and Fellows of Harvard College. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * This file is shared between libc and the kernel, so don't put anything * in here that won't work in both contexts. */ #ifdef _KERNEL #include <types.h> #include <lib.h> #else #include <stdint.h> #include <string.h> #endif /* * C standard function - copy a block of memory. */ void * memcpy(void *dst, const void *src, size_t len) { size_t i; /* * memcpy does not support overlapping buffers, so always do it * forwards. (Don't change this without adjusting memmove.) * * For speedy copying, optimize the common case where both pointers * and the length are word-aligned, and copy word-at-a-time instead * of byte-at-a-time. Otherwise, copy by bytes. * * The alignment logic below should be portable. We rely on * the compiler to be reasonably intelligent about optimizing * the divides and modulos out. Fortunately, it is. */ if ((uintptr_t)dst % sizeof(long) == 0 && (uintptr_t)src % sizeof(long) == 0 && len % sizeof(long) == 0) { long *d = dst; const long *s = src; for (i=0; i<len/sizeof(long); i++) { d[i] = s[i]; } } else { char *d = dst; const char *s = src; for (i=0; i<len; i++) { d[i] = s[i]; } } return dst; }