1 files changed, 69 insertions, 0 deletions
diff --git a/gr-digital/lib/digital_additive_scrambler_bb.cc b/gr-digital/lib/digital_additive_scrambler_bb.cc
new file mode 100644
index 000000000..a8affaa78
--- /dev/null
+++ b/gr-digital/lib/digital_additive_scrambler_bb.cc
@@ -0,0 +1,69 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2010,2012 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <digital_additive_scrambler_bb.h>
+#include <gr_io_signature.h>
+
+digital_additive_scrambler_bb_sptr
+digital_make_additive_scrambler_bb(int mask, int seed, int len, int count)
+{
+  return gnuradio::get_initial_sptr(new digital_additive_scrambler_bb
+				    (mask, seed, len, count));
+}
+
+digital_additive_scrambler_bb::digital_additive_scrambler_bb(int mask,
+							     int seed,
+							     int len,
+							     int count)
+  : gr_sync_block("additive_scrambler_bb",
+		  gr_make_io_signature (1, 1, sizeof (unsigned char)),
+		  gr_make_io_signature (1, 1, sizeof (unsigned char))),
+    d_lfsr(mask, seed, len),
+    d_count(count),
+    d_bits(0)
+{
+}
+
+int
+digital_additive_scrambler_bb::work(int noutput_items,
+				    gr_vector_const_void_star &input_items,
+				    gr_vector_void_star &output_items)
+{
+  const unsigned char *in = (const unsigned char *) input_items[0];
+  unsigned char *out = (unsigned char *) output_items[0];
+
+  for (int i = 0; i < noutput_items; i++) {
+    out[i] = in[i]^d_lfsr.next_bit();
+    if (d_count > 0) {
+      if (++d_bits == d_count) {
+	d_lfsr.reset();
+	d_bits = 0;
+      }
+    }
+  }
+
+  return noutput_items;
+}