match memmove() implementation without malloc()

1 files changed, 19 insertions, 4 deletions

diff --git a/src/wchar/wmemmove.c b/src/wchar/wmemmove.c
index 11fd35dc..75b58f87 100644
--- a/src/wchar/wmemmove.c
+++ b/src/wchar/wmemmove.c
@@ -1,12 +1,27 @@
 #include <wchar.h>
 #include "stdlib.h"
+#include "nonstd/assert.h"
 
 wchar_t * wmemmove(wchar_t * s1, const wchar_t * s2, size_t n)
 {
-	wchar_t *tmp = malloc(n * sizeof(wchar_t));
-	wmemcpy(tmp, s2, n);
-	wmemcpy(s1, tmp, n);
-	free(tmp);
+	ASSERT_NONNULL(s1);
+	ASSERT_NONNULL(s2);
+
+	if (s1 < s2) {
+		return wmemcpy(s1, s2, n);
+	}
+
+	/* reverse memcpy() */
+	while (n > 0) {
+		s1[n] = s2[n];
+		n--;
+	}
+	/* last byte */
+	s1[n] = s2[n];
+
+	/*
+	RETURN_ALWAYS(ARGUMENT(s1));
+	*/
 	return s1;
 }