/* -*- c++ -*- */

/*

 * Copyright 2004,2006,2010 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_framer_sink_1.h>

#include <gr_io_signature.h>

#include <cstdio>

#include <stdexcept>

#include <string.h>

#define VERBOSE 0

inline void

gr_framer_sink_1::enter_search()

{

  if (VERBOSE)

    fprintf(stderr, "@ enter_search\n");

  d_state = STATE_SYNC_SEARCH;

}

inline void

gr_framer_sink_1::enter_have_sync()

{

  if (VERBOSE)

    fprintf(stderr, "@ enter_have_sync\n");

  d_state = STATE_HAVE_SYNC;

  d_header = 0;

  d_headerbitlen_cnt = 0;

}

inline void

gr_framer_sink_1::enter_have_header(int payload_len, int whitener_offset)

{

  if (VERBOSE)

    fprintf(stderr, "@ enter_have_header (payload_len = %d) (offset = %d)\n", payload_len, whitener_offset);

  d_state = STATE_HAVE_HEADER;

  d_packetlen = payload_len;

  d_packet_whitener_offset = whitener_offset;

  d_packetlen_cnt = 0;

  d_packet_byte = 0;

  d_packet_byte_index = 0;

}

gr_framer_sink_1_sptr

gr_make_framer_sink_1(gr_msg_queue_sptr target_queue)

{

  return gnuradio::get_initial_sptr(new gr_framer_sink_1(target_queue));

}

gr_framer_sink_1::gr_framer_sink_1(gr_msg_queue_sptr target_queue)

  : gr_sync_block ("framer_sink_1",

                   gr_make_io_signature (1, 1, sizeof(unsigned char)),

                   gr_make_io_signature (0, 0, 0)),

    d_target_queue(target_queue)

{

  enter_search();

}

gr_framer_sink_1::~gr_framer_sink_1 ()

{

}

int

gr_framer_sink_1::work (int noutput_items,

                        gr_vector_const_void_star &input_items,

                        gr_vector_void_star &output_items)

{

  const unsigned char *in = (const unsigned char *) input_items[0];

  int count=0;

  if (VERBOSE)

    fprintf(stderr,">>> Entering state machine\n");

  while (count < noutput_items){

    switch(d_state) {

    case STATE_SYNC_SEARCH:    // Look for flag indicating beginning of pkt

      if (VERBOSE)

        fprintf(stderr,"SYNC Search, noutput=%d\n", noutput_items);

      while (count < noutput_items) {

        if (in[count] & 0x2){  // Found it, set up for header decode

          enter_have_sync();

          break;

        }

        count++;

      }

      break;

    case STATE_HAVE_SYNC:

      if (VERBOSE)

        fprintf(stderr,"Header Search bitcnt=%d, header=0x%08x\n",

                d_headerbitlen_cnt, d_header);

      while (count < noutput_items) {        // Shift bits one at a time into header

        d_header = (d_header << 1) | (in[count++] & 0x1);

        if (++d_headerbitlen_cnt == HEADERBITLEN) {

          if (VERBOSE)

            fprintf(stderr, "got header: 0x%08x\n", d_header);

          // we have a full header, check to see if it has been received properly

          if (header_ok()){

            int payload_len;

            int whitener_offset;

            header_payload(&payload_len, &whitener_offset);

            enter_have_header(payload_len, whitener_offset);

            if (d_packetlen == 0){            // check for zero-length payload

              // build a zero-length message

              // NOTE: passing header field as arg1 is not scalable

              gr_message_sptr msg =

                gr_make_message(0, d_packet_whitener_offset, 0, 0);

              d_target_queue->insert_tail(msg);                // send it

              msg.reset();                                  // free it up

              enter_search();                                

            }

          }

          else

            enter_search();                                // bad header

          break;                                        // we're in a new state

        }

      }

      break;

    case STATE_HAVE_HEADER:

      if (VERBOSE)

        fprintf(stderr,"Packet Build\n");

      while (count < noutput_items) {   // shift bits into bytes of packet one at a time

        d_packet_byte = (d_packet_byte << 1) | (in[count++] & 0x1);

        if (d_packet_byte_index++ == 7) {                  // byte is full so move to next byte

          d_packet[d_packetlen_cnt++] = d_packet_byte;

          d_packet_byte_index = 0;

          if (d_packetlen_cnt == d_packetlen){                // packet is filled

            // build a message

            // NOTE: passing header field as arg1 is not scalable

            gr_message_sptr msg =

              gr_make_message(0, d_packet_whitener_offset, 0, d_packetlen_cnt);

            memcpy(msg->msg(), d_packet, d_packetlen_cnt);

            d_target_queue->insert_tail(msg);                // send it

            msg.reset();                                  // free it up

            enter_search();

            break;

          }

        }

      }

      break;

    default:

      assert(0);

    } // switch

  }   // while

  return noutput_items;

}