implement isc_dynbuffer_reset()

lib/isc/buffer.c

@@ -379,6 +379,14 @@ isc_dynbuffer_allocate(isc_mem_t *mctx, isc_dynbuffer_t **dynbuffer,
 	return (ISC_R_SUCCESS);
 }
 
+void
+isc_dynbuffer_reset(isc_dynbuffer_t *dynbuffer)
+{
+	REQUIRE(VALID_DYNBUFFER(dynbuffer));
+
+	isc_buffer_clear(&dynbuffer->buffer);
+}
+
 void
 isc_dynbuffer_free(isc_mem_t *mctx, isc_dynbuffer_t **dynbuffer)
 {

lib/isc/include/isc/buffer.h

@@ -171,6 +171,13 @@ isc_dynbuffer_allocate(isc_mem_t *mctx, isc_dynbuffer_t **dynbuffer,
  *	ISC_R_NOMEMORY		- no memory available
  */
 
+void
+isc_dynbuffer_reset(isc_dynbuffer_t *dynbuffer);
+/*
+ * Reset the dynamic buffer to the initial state
+ */
+
+
 void
 isc_dynbuffer_free(isc_mem_t *mctx, isc_dynbuffer_t **dynbuffer);
 /*