From 102b0d2daa97dae68d3eed54d8fe37a9cc38a892 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 11:13:47 +0200 Subject: Adding upstream version 2.8.0+dfsg. Signed-off-by: Daniel Baumann --- lib/libc/memmove.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 lib/libc/memmove.c (limited to 'lib/libc/memmove.c') diff --git a/lib/libc/memmove.c b/lib/libc/memmove.c new file mode 100644 index 0000000..63acf26 --- /dev/null +++ b/lib/libc/memmove.c @@ -0,0 +1,31 @@ +/* + * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include + +void *memmove(void *dst, const void *src, size_t len) +{ + /* + * The following test makes use of unsigned arithmetic overflow to + * more efficiently test the condition !(src <= dst && dst < str+len). + * It also avoids the situation where the more explicit test would give + * incorrect results were the calculation str+len to overflow (though + * that issue is probably moot as such usage is probably undefined + * behaviour and a bug anyway. + */ + if ((size_t)dst - (size_t)src >= len) { + /* destination not in source data, so can safely use memcpy */ + return memcpy(dst, src, len); + } else { + /* copy backwards... */ + const char *end = dst; + const char *s = (const char *)src + len; + char *d = (char *)dst + len; + while (d != end) + *--d = *--s; + } + return dst; +} -- cgit v1.2.3