32 lines
927 B
C
32 lines
927 B
C
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/*
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* Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <string.h>
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void *memmove(void *dst, const void *src, size_t len)
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{
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/*
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* The following test makes use of unsigned arithmetic overflow to
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* more efficiently test the condition !(src <= dst && dst < str+len).
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* It also avoids the situation where the more explicit test would give
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* incorrect results were the calculation str+len to overflow (though
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* that issue is probably moot as such usage is probably undefined
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* behaviour and a bug anyway.
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*/
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if ((size_t)dst - (size_t)src >= len) {
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/* destination not in source data, so can safely use memcpy */
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return memcpy(dst, src, len);
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} else {
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/* copy backwards... */
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const char *end = dst;
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const char *s = (const char *)src + len;
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char *d = (char *)dst + len;
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while (d != end)
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*--d = *--s;
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}
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return dst;
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}
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