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/* -*- c++ -*- */
/*
* Copyright 2004,2006,2010,2012 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "framer_sink_1_impl.h"
#include <gnuradio/io_signature.h>
#include <cstdio>
#include <string>
namespace gr {
namespace digital {
#define VERBOSE 0
inline void framer_sink_1_impl::enter_search()
{
if (VERBOSE)
fprintf(stderr, "@ enter_search\n");
d_state = STATE_SYNC_SEARCH;
}
inline void framer_sink_1_impl::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 framer_sink_1_impl::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;
}
framer_sink_1::sptr framer_sink_1::make(msg_queue::sptr target_queue)
{
return gnuradio::get_initial_sptr(new framer_sink_1_impl(target_queue));
}
framer_sink_1_impl::framer_sink_1_impl(msg_queue::sptr target_queue)
: sync_block("framer_sink_1",
io_signature::make(1, 1, sizeof(unsigned char)),
io_signature::make(0, 0, 0)),
d_target_queue(target_queue)
{
enter_search();
}
framer_sink_1_impl::~framer_sink_1_impl() {}
int framer_sink_1_impl::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
message::sptr msg =
message::make(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
message::sptr msg = message::make(
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;
}
} /* namespace digital */
} /* namespace gr */
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