1 files changed, 152 insertions, 0 deletions
diff --git a/gr-fec/lib/ccsds_encoder_impl.cc b/gr-fec/lib/ccsds_encoder_impl.cc
new file mode 100644
index 0000000000..2a2228a8ed
--- /dev/null
+++ b/gr-fec/lib/ccsds_encoder_impl.cc
@@ -0,0 +1,152 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2014 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 "ccsds_encoder_impl.h"
+#include <gnuradio/fec/generic_encoder.h>
+#include <cstdio>
+
+extern "C" {
+#include <gnuradio/fec/viterbi.h>
+}
+
+namespace gr {
+  namespace fec {
+    namespace code {
+
+      generic_encoder::sptr
+      ccsds_encoder::make(int frame_size, int start_state,
+                          cc_mode_t mode)
+      {
+        return generic_encoder::sptr
+          (new ccsds_encoder_impl(frame_size, start_state, mode));
+      }
+
+      ccsds_encoder_impl::ccsds_encoder_impl(int frame_size, int start_state,
+                                             cc_mode_t mode)
+        : generic_encoder("ccsds_encoder"),
+          d_start_state(static_cast<unsigned char>(start_state)),
+          d_mode(mode)
+      {
+        d_max_frame_size = frame_size;
+        set_frame_size(frame_size);
+      }
+
+      ccsds_encoder_impl::~ccsds_encoder_impl()
+      {
+      }
+
+      int
+      ccsds_encoder_impl::get_output_size()
+      {
+        return d_output_size;
+      }
+
+      int
+      ccsds_encoder_impl::get_input_size()
+      {
+        return d_frame_size/8; // packed byte input
+      }
+
+      const char*
+      ccsds_encoder_impl::get_input_conversion()
+      {
+        // Expects packed data input; tell wrapper to pack it.
+        return "pack";
+      }
+
+      bool
+      ccsds_encoder_impl::set_frame_size(unsigned int frame_size)
+      {
+        bool ret = true;
+        if(frame_size > d_max_frame_size) {
+          GR_LOG_INFO(d_logger, boost::format("tried to set frame to %1%; max possible is %2%") \
+                      % frame_size % d_max_frame_size);
+          frame_size = d_max_frame_size;
+          ret = false;
+        }
+
+        d_frame_size = frame_size;
+
+        if(d_mode == CC_TERMINATED) {
+          d_output_size = 2*(d_frame_size + 7 - 1);
+        }
+        else {
+          d_output_size = 2*d_frame_size;
+        }
+
+        return ret;
+      }
+
+      double
+      ccsds_encoder_impl::rate()
+      {
+        return 0.5;
+      }
+
+      void
+      ccsds_encoder_impl::generic_work(void *in_buffer, void *out_buffer)
+      {
+        unsigned char *in = (unsigned char*) in_buffer;
+        unsigned char *out = (unsigned char*) out_buffer;
+
+        unsigned char my_state = d_start_state;
+
+        if(d_mode == CC_TAILBITING) {
+          // Grab K-1 (6) bits of data from the last input byte to add
+          // onto the from of the encoding stream for tailbiting mode.
+          unsigned char sym = in[d_frame_size/8 - 1];
+          for(unsigned int i = 0; i < 7 - 1; ++i) {
+            my_state = (my_state << 1) | ((sym >> (5 - i)) & 1);
+          }
+        }
+
+        my_state = encode(out, in, d_frame_size/8, my_state);
+
+        if(d_mode == CC_TERMINATED) {
+          // encode works on bytes, but we are only adding some number
+          // of bits to the end of the frame, so we abuse the encode
+          // function by reshifting the start state within the
+          // for-loop and only taking the last two bits out of the
+          // encoded 2-bytes.
+          unsigned char end_bits[16];
+          for(unsigned int i = 0; i < (7 - 1); ++i) {
+            my_state = (my_state << 1) | ((d_start_state >> (7 - 2 - i)) & 1);
+            encode(&end_bits[0], &my_state, 1, my_state);
+            out[(i + d_frame_size) * 2 + 0] = end_bits[14];
+            out[(i + d_frame_size) * 2 + 1] = end_bits[15];
+          }
+        }
+
+        if(d_mode == CC_TRUNCATED) {
+          my_state = d_start_state;
+        }
+
+        d_start_state = my_state;
+      }
+
+    } /* namespace code */
+  } /* namespace fec */
+} /* namespace gr */