diff options
Diffstat (limited to 'gr-digital/lib/crc32_bb_impl.cc')
| -rw-r--r-- | gr-digital/lib/crc32_bb_impl.cc | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/gr-digital/lib/crc32_bb_impl.cc b/gr-digital/lib/crc32_bb_impl.cc new file mode 100644 index 0000000000..608c5758ac --- /dev/null +++ b/gr-digital/lib/crc32_bb_impl.cc @@ -0,0 +1,105 @@ +/* -*- c++ -*- */ +/* + * Copyright 2013 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 <gr_io_signature.h> +#include "crc32_bb_impl.h" +#include <digital/crc32.h> + +namespace gr { + namespace digital { + + crc32_bb::sptr + crc32_bb::make(bool check, const std::string& lengthtagname) + { + return gnuradio::get_initial_sptr (new crc32_bb_impl(check, lengthtagname)); + } + + crc32_bb_impl::crc32_bb_impl(bool check, const std::string& lengthtagname) + : gr_tagged_stream_block("crc32_bb", + gr_make_io_signature(1, 1, sizeof (char)), + gr_make_io_signature(1, 1, sizeof (char)), + lengthtagname), + d_check(check) + { + set_tag_propagation_policy(TPP_DONT); + } + + crc32_bb_impl::~crc32_bb_impl() + { + } + + int + crc32_bb_impl::calculate_output_stream_length(const gr_vector_int &ninput_items) + { + if (d_check) { + return ninput_items[0] - 4; + } else { + return ninput_items[0] + 4; + } + } + + int + crc32_bb_impl::work (int noutput_items, + gr_vector_int &ninput_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]; + long packet_length = ninput_items[0]; + int packet_size_diff = d_check ? -4 : 4; + unsigned int crc; + + if (d_check) { + crc = gr::digital::crc32(in, packet_length-4); + if (crc != *(unsigned int *)(in+packet_length-4)) { // Drop package + return 0; + } + memcpy((void *) out, (const void *) in, packet_length-4); + } else { + crc = gr::digital::crc32(in, packet_length); + memcpy((void *) out, (const void *) in, packet_length); + memcpy((void *) (out + packet_length), &crc, 4); // FIXME big-endian/little-endian, this might be wrong + } + + std::vector<gr_tag_t> tags; + get_tags_in_range(tags, 0, nitems_read(0), nitems_read(0)+packet_length); + for (unsigned i = 0; i < tags.size(); i++) { + tags[i].offset -= nitems_read(0); + if (d_check && tags[i].offset > packet_length+packet_size_diff) { + tags[i].offset = packet_length-5; + } + add_item_tag(0, nitems_written(0) + tags[i].offset, + tags[i].key, + tags[i].value); + } + + return packet_length + packet_size_diff; + } + + } /* namespace digital */ +} /* namespace gr */ + |