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/* -*- c++ -*- */
/* Copyright 2016 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 <gnuradio/digital/header_buffer.h>
#include <gnuradio/digital/header_format_crc.h>
#include <volk/volk_alloc.hh>
#include <cstring>
namespace gr {
namespace digital {
header_format_crc::sptr header_format_crc::make(const std::string& len_key_name,
const std::string& num_key_name)
{
return header_format_crc::sptr(new header_format_crc(len_key_name, num_key_name));
}
header_format_crc::header_format_crc(const std::string& len_key_name,
const std::string& num_key_name)
: header_format_base(), d_header_number(0)
{
d_len_key_name = pmt::intern(len_key_name);
d_num_key_name = pmt::intern(num_key_name);
}
header_format_crc::~header_format_crc() {}
bool header_format_crc::format(int nbytes_in,
const unsigned char* input,
pmt::pmt_t& output,
pmt::pmt_t& info)
{
// Creating the output pmt copies data; free our own here when done.
volk::vector<uint8_t> bytes_out(header_nbytes());
// Should this throw instead of mask if the payload is too big
// for 12-bit representation?
nbytes_in &= 0x0FFF;
d_crc_impl.reset();
d_crc_impl.process_bytes((void const*)&nbytes_in, 2);
d_crc_impl.process_bytes((void const*)&d_header_number, 2);
uint8_t crc = d_crc_impl();
// Form 2 12-bit items into 1 2-byte item
uint32_t concat = 0;
concat = (d_header_number << 12) | (nbytes_in);
header_buffer header(bytes_out.data());
header.add_field32(concat, 24, true);
header.add_field8(crc);
d_header_number++;
d_header_number &= 0x0FFF;
// Package output data into a PMT vector
output = pmt::init_u8vector(header_nbytes(), bytes_out.data());
return true;
}
bool header_format_crc::parse(int nbits_in,
const unsigned char* input,
std::vector<pmt::pmt_t>& info,
int& nbits_processed)
{
while (nbits_processed <= nbits_in) {
d_hdr_reg.insert_bit(input[nbits_processed++]);
if (d_hdr_reg.length() == header_nbits()) {
if (header_ok()) {
int payload_len = header_payload();
enter_have_header(payload_len);
info.push_back(d_info);
d_hdr_reg.clear();
return true;
} else {
d_hdr_reg.clear();
return false;
}
break;
}
}
return true;
}
size_t header_format_crc::header_nbits() const { return 32; }
bool header_format_crc::header_ok()
{
uint32_t pkt = d_hdr_reg.extract_field32(0, 24, true);
uint16_t pktlen = static_cast<uint16_t>((pkt >> 8) & 0x0fff);
uint16_t pktnum = static_cast<uint16_t>((pkt >> 20) & 0x0fff);
uint8_t crc_rcvd = d_hdr_reg.extract_field8(24);
// Check CRC8
d_crc_impl.reset();
d_crc_impl.process_bytes((void const*)&pktlen, 2);
d_crc_impl.process_bytes((void const*)&pktnum, 2);
uint8_t crc_clcd = d_crc_impl();
return (crc_rcvd == crc_clcd);
}
int header_format_crc::header_payload()
{
uint32_t pkt = d_hdr_reg.extract_field32(0, 24, true);
uint16_t pktlen = static_cast<uint16_t>((pkt >> 8) & 0x0fff);
uint16_t pktnum = static_cast<uint16_t>((pkt >> 20) & 0x0fff);
d_info = pmt::make_dict();
d_info = pmt::dict_add(d_info, d_len_key_name, pmt::from_long(8 * pktlen));
d_info = pmt::dict_add(d_info, d_num_key_name, pmt::from_long(pktnum));
return static_cast<int>(pktlen);
}
} /* namespace digital */
} /* namespace gr */
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