diff --git a/src/main/c/util/pipe.c b/src/main/c/util/pipe.c
index 71f107d..9842b07 100644
--- a/src/main/c/util/pipe.c
+++ b/src/main/c/util/pipe.c
@@ -17,6 +17,7 @@ typedef struct hbu_pipe_s {
   hbu_fstreamin_t input;
   void *output;
   hbu_pipe_writer_cb_t writer;
+  int output_masked;
 
   hbu_buffer_t buffer;
 
@@ -116,7 +117,9 @@ static void _hbu_pipe_assert_not_eoi(hbu_pipe_t pipe, hb_eod_char_t c) {
 }
 
 static void _hbu_pipe_write_to_output(hbu_pipe_t pipe, hb_char_t c) {
-  (*pipe->writer)(pipe->output, c);
+  if (!pipe->output_masked) {
+    (*pipe->writer)(pipe->output, c);
+  }
 }
 
 /*
@@ -130,6 +133,7 @@ hbu_pipe_t hbu_pipe_create(hbu_fstreamin_t input, void *output, hbu_pipe_writer_
   pipe->input = input;
   pipe->output = output;
   pipe->writer = writer;
+  pipe->output_masked = 0;
 
   pipe->buffer = hbu_buffer_create();
 
@@ -146,6 +150,10 @@ void hbu_pipe_destroy(hbu_pipe_t pipe) {
   free(pipe);
 }
 
+void hbu_pipe_toggle_output_mask(hbu_pipe_t pipe, int output_masked) {
+  pipe->output_masked = output_masked;
+}
+
 /*
  *
  * BUILDER FUNCTIONS