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/* -*- c++ -*- */
/*
* Copyright 2004,2006,2010,2012 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <digital_framer_sink_1.h>
#include <gr_io_signature.h>
#include <cstdio>
#include <stdexcept>
#include <string.h>
#define VERBOSE 0
inline void
digital_framer_sink_1::enter_search()
{
if (VERBOSE)
fprintf(stderr, "@ enter_search\n");
d_state = STATE_SYNC_SEARCH;
}
inline void
digital_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
digital_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;
}
digital_framer_sink_1_sptr
digital_make_framer_sink_1(gr_msg_queue_sptr target_queue)
{
return gnuradio::get_initial_sptr(new digital_framer_sink_1(target_queue));
}
digital_framer_sink_1::digital_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();
}
digital_framer_sink_1::~digital_framer_sink_1 ()
{
}
int
digital_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;
}
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