varlen_packet_framer.h

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/* -*- c++ -*- */
/*
 * Copyright 2017 Glenn Richardson <glenn@spacequest.com> 
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>
 */

#ifndef INCLUDED_VARLEN_PACKET_FRAMER_H
#define INCLUDED_VARLEN_PACKET_FRAMER_H

#include <satellites/api.h>
#include <gnuradio/block.h>
#include <gnuradio/endianness.h>
#include <pmt/pmt.h>

namespace gr {
  namespace satellites {
    /*!
     * \brief insert a packet length field into a tagged stream 
     * \ingroup satellites
     *
     * \details
     * input: stream of bits (unpacked bytes) with packet_len tags
     * output: a tagged stream of bits containing field length + packet bits
     *
     * This block prepends a packet length field into a tagged stream.
     *
     */
    class SATELLITES_API varlen_packet_framer : virtual public gr::block
    {
    public:
      typedef boost::shared_ptr<varlen_packet_framer> sptr;

      /*!
       * \param packet_key        tag key used to mark packets
       * \param length_field_size size of the packet length header
       * \param endianness        header inserted msb or lsb
       * \param use_golay         compute 24-bit golay header from 12-bit length
       * \param sync_word         optional pre-header sync pattern
       */
      static sptr make(const std::string &packet_key,
                       int length_field_size,
                       endianness_t endianness,
                       bool use_golay,
                       const std::vector<uint8_t> sync_word);
    };

  } // namespace satellites
} // namespace gr

#endif