diff options
| author | Tom Rondeau <tom@trondeau.com> | 2014-05-17 19:23:44 -0400 |
|---|---|---|
| committer | Tom Rondeau <tom@trondeau.com> | 2014-05-17 19:23:44 -0400 |
| commit | 91b5f380b6c511624064f1b64ae3ebfd710d7272 (patch) | |
| tree | 5c157b11cebf25e110d26f8829287f0b97fb0bfd /gr-fec/lib/cc_encoder_impl.cc | |
| parent | 3245fde378417687db10f7cdeb274c9fa126d4e8 (diff) | |
fec: wip: adding concept of padding for CC encoder/decoder.
When using terminated mode, the CC encoder adds K-1 bits to the output, which doesn't fit a full byte and will throw off the book-keeping in PDU or tagged mode. Padding to fill a byte tells both encoder and decoder to handle the extra bits.
Diffstat (limited to 'gr-fec/lib/cc_encoder_impl.cc')
| -rw-r--r-- | gr-fec/lib/cc_encoder_impl.cc | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/gr-fec/lib/cc_encoder_impl.cc b/gr-fec/lib/cc_encoder_impl.cc index abbf1a8f1b..90d2ee4c1c 100644 --- a/gr-fec/lib/cc_encoder_impl.cc +++ b/gr-fec/lib/cc_encoder_impl.cc @@ -42,21 +42,21 @@ namespace gr { generic_encoder::sptr cc_encoder::make(int frame_size, int k, int rate, std::vector<int> polys, int start_state, - cc_mode_t mode) + cc_mode_t mode, bool padded) { return generic_encoder::sptr (new cc_encoder_impl(frame_size, k, rate, polys, start_state, - mode)); + mode, padded)); } cc_encoder_impl::cc_encoder_impl(int frame_size, int k, int rate, std::vector<int> polys, int start_state, - cc_mode_t mode) + cc_mode_t mode, bool padded) : generic_encoder("cc_encoder"), d_rate(rate), d_k(k), d_polys(polys), d_start_state(start_state), - d_mode(mode) + d_mode(mode), d_padding(0) { if(static_cast<size_t>(d_rate) != d_polys.size()) { throw std::runtime_error("cc_encoder: Number of polynomials must be the same as the value of rate"); @@ -64,6 +64,12 @@ namespace gr { partab_init(); + // set up a padding factor. If padding, extends the encoding + // by this many bits to fit into a full byte. + if(padded && (mode == CC_TERMINATED)) { + d_padding = static_cast<int>(8.0f*ceilf(d_rate*(d_k-1)/8.0f) - (d_rate*(d_k-1))); + } + d_max_frame_size = frame_size; set_frame_size(frame_size); } @@ -98,7 +104,7 @@ namespace gr { d_frame_size = frame_size; if(d_mode == CC_TERMINATED) { - d_output_size = d_rate * (d_frame_size + d_k - 1); + d_output_size = d_rate * (d_frame_size + d_k - 1) + d_padding; } /* else if(d_trunc_intrinsic) { |