1 files changed, 43 insertions, 0 deletions
diff --git a/contrib/unbound/compat/memmove.c b/contrib/unbound/compat/memmove.c
new file mode 100644
index 000000000000..0035bbf7533d
--- /dev/null
+++ b/contrib/unbound/compat/memmove.c
@@ -0,0 +1,43 @@
+/*
+ *	memmove.c: memmove compat implementation.
+ *
+ *	Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
+ *
+ * See LICENSE for the license.
+*/
+
+#include <config.h>
+#include <stdlib.h>
+
+void *memmove(void *dest, const void *src, size_t n);
+
+void *memmove(void *dest, const void *src, size_t n)
+{
+	uint8_t* from = (uint8_t*) src;
+	uint8_t* to = (uint8_t*) dest;
+
+	if (from == to || n == 0)
+		return dest;
+	if (to > from && to-from < (int)n) {
+		/* to overlaps with from */
+		/*  <from......>         */
+		/*         <to........>  */
+		/* copy in reverse, to avoid overwriting from */
+		int i;
+		for(i=n-1; i>=0; i--)
+			to[i] = from[i];
+		return dest;
+	}
+	if (from > to  && from-to < (int)n) {
+		/* to overlaps with from */
+		/*        <from......>   */
+		/*  <to........>         */
+		/* copy forwards, to avoid overwriting from */
+		size_t i;
+		for(i=0; i<n; i++)
+			to[i] = from[i];
+		return dest;
+	}
+	memcpy(dest, src, n);
+	return dest;
+}