/* -*- c++ -*- */
/* Copyright 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.
 */

#ifndef INCLUDED_DIGITAL_PACKET_HEADER_DEFAULT_H
#define INCLUDED_DIGITAL_PACKET_HEADER_DEFAULT_H

#include <gr_tags.h>
#include <digital/api.h>
#include <boost/enable_shared_from_this.hpp>

namespace gr {
  namespace digital {

    /*!
     * \brief <+description of block+>
     * \ingroup digital
     *
     */
    class DIGITAL_API packet_header_default : public boost::enable_shared_from_this<gr::digital::packet_header_default>
    {
     public:
      typedef boost::shared_ptr<packet_header_default> sptr;

      packet_header_default(
		      long header_len,
		      const std::string &len_tag_key="packet_len",
		      const std::string &num_tag_key="packet_num",
		      int bits_per_byte=1);
      ~packet_header_default();

      sptr base() { return shared_from_this(); };
      sptr formatter() { return shared_from_this(); };

      void set_header_num(unsigned header_num) { d_header_number = header_num; };
      long header_len() { return d_header_len; };
      pmt::pmt_t len_tag_key() { return d_len_tag_key; };

      /* \brief Encodes the header information in the given tags into bits and places them into \p out
       *
       * Uses the following header format:
       * Bits 0-11: The packet length (what was stored in the tag with key \p len_tag_key)
       * Bits 12-27: The header number (counts up everytime this function is called)
       * Bit 28: Even parity bit
       * All other bits: Are set to zero
       *
       * If the header length is smaller than 29, bits are simply left out. For this
       * reason, they always start with the LSB.
       */
      bool header_formatter(
	  long packet_len,
	  unsigned char *out,
	  const std::vector<gr_tag_t> &tags=std::vector<gr_tag_t>()
      );

      /* \brief Inverse function to header_formatter().
       *
       * Reads the bit stream in \in and writes a corresponding tag into \p tags.
       *
       */
      bool header_parser(
	const unsigned char *header,
	std::vector<gr_tag_t> &tags);

      static sptr make(
	      long header_len,
	      const std::string &len_tag_key="packet_len",
	      const std::string &num_tag_key="packet_num",
	      int bits_per_byte=1);

    protected:
      long d_header_len;
      pmt::pmt_t d_len_tag_key;
      pmt::pmt_t d_num_tag_key;
      int d_bits_per_byte;
      unsigned d_header_number;
      unsigned d_mask;
    };

  } // namespace digital
} // namespace gr

#endif /* INCLUDED_DIGITAL_PACKET_HEADER_DEFAULT_H */