diff --git a/src/lib9/utf/utfecpy.c b/src/lib9/utf/utfecpy.c
new file mode 100644
index 0000000..5715935
--- /dev/null
+++ b/src/lib9/utf/utfecpy.c
@@ -0,0 +1,36 @@
+/*
+ * The authors of this software are Rob Pike and Ken Thompson.
+ *              Copyright (c) 2002 by Lucent Technologies.
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose without fee is hereby granted, provided that this entire notice
+ * is included in all copies of any software which is or includes a copy
+ * or modification of this software and in all copies of the supporting
+ * documentation for such software.
+ * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
+ * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
+ * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
+ */
+#include <stdarg.h>
+#include <string.h>
+#include "utf.h"
+#include "utfdef.h"
+
+char*
+utfecpy(char *to, char *e, char *from)
+{
+	char *end;
+
+	if(to >= e)
+		return to;
+	end = memccpy(to, from, '\0', e - to);
+	if(end == nil){
+		end = e-1;
+		while(end>to && (*--end&0xC0)==0x80)
+			;
+		*end = '\0';
+	}else{
+		end--;
+	}
+	return end;
+}