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/* -*- c++ -*- */
/*
* Copyright 2005 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_GR_PACKET_SINK_H
#define INCLUDED_GR_PACKET_SINK_H
#include <gr_core_api.h>
#include <gr_sync_block.h>
#include <gr_msg_queue.h>
class gr_packet_sink;
typedef boost::shared_ptr<gr_packet_sink> gr_packet_sink_sptr;
GR_CORE_API gr_packet_sink_sptr
gr_make_packet_sink (const std::vector<unsigned char>& sync_vector,
gr_msg_queue_sptr target_queue,
int threshold = -1 // -1 -> use default
);
/*!
* \brief process received bits looking for packet sync, header, and process bits into packet
* \ingroup sink_blk
*/
class GR_CORE_API gr_packet_sink : public gr_sync_block
{
friend GR_CORE_API gr_packet_sink_sptr
gr_make_packet_sink (const std::vector<unsigned char>& sync_vector,
gr_msg_queue_sptr target_queue,
int threshold);
private:
enum state_t {STATE_SYNC_SEARCH, STATE_HAVE_SYNC, STATE_HAVE_HEADER};
static const int MAX_PKT_LEN = 4096;
static const int HEADERBITLEN = 32;
gr_msg_queue_sptr d_target_queue; // where to send the packet when received
unsigned long long d_sync_vector; // access code to locate start of packet
unsigned int d_threshold; // how many bits may be wrong in sync vector
state_t d_state;
unsigned long long d_shift_reg; // used to look for sync_vector
unsigned int d_header; // header bits
int d_headerbitlen_cnt; // how many so far
unsigned char d_packet[MAX_PKT_LEN]; // assembled payload
unsigned char d_packet_byte; // byte being assembled
int d_packet_byte_index; // which bit of d_packet_byte we're working on
int d_packetlen; // length of packet
int d_packetlen_cnt; // how many so far
protected:
gr_packet_sink(const std::vector<unsigned char>& sync_vector,
gr_msg_queue_sptr target_queue,
int threshold);
void enter_search();
void enter_have_sync();
void enter_have_header(int payload_len);
int slice(float x) { return x > 0 ? 1 : 0; }
bool header_ok()
{
// confirm that two copies of header info are identical
return ((d_header >> 16) ^ (d_header & 0xffff)) == 0;
}
int header_payload_len()
{
// header consists of two 16-bit shorts in network byte order
int t = (d_header >> 16) & 0xffff;
return t;
}
public:
~gr_packet_sink();
int work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items);
//! return true if we detect carrier
bool carrier_sensed() const
{
return d_state != STATE_SYNC_SEARCH;
}
};
#endif /* INCLUDED_GR_PACKET_SINK_H */
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