core/lib/memmove.c

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 * Copyright (c) 2012-2019 Google, Inc.  All rights reserved.
 * **********************************************************/

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/*
 * Private memmove for inclusion in libdrmemfuncs for isolation from libc in
 * shared DR but not in static DR.  We need this in addition to memcpy
 * and memset because the compiler will auto-issue a call to "memmove" when
 * it cannot prove there are is no overlap and that memcpy is safe to call.
 *
 * We assume that this is not performance-critical as it is rarely called
 * (in fact it only shows up once in the internal release build and not at
 * all in the external release build) and so we just use simple C code.
 */

#include "../globals.h"

#undef memmove

void *
memmove(void *dst, const void *src, size_t n)
{
    ssize_t i;
    byte *dst_b = (byte *)dst;
    const byte *src_b = (const byte *)src;
    if (dst < src)
        return memcpy(dst, src, n);
    for (i = n - 1; i >= 0; i--) {
        dst_b[i] = src_b[i];
    }
    return dst;
}