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/* -*- c++ -*- */
/* Copyright 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 <gnuradio/digital/packet_header_default.h>
#include <cstring>
namespace gr {
namespace digital {
packet_header_default::sptr packet_header_default::make(long header_len,
const std::string& len_tag_key,
const std::string& num_tag_key,
int bits_per_byte)
{
return packet_header_default::sptr(
new packet_header_default(header_len, len_tag_key, num_tag_key, bits_per_byte));
}
const unsigned MASK_LUT[9] = { 0x00, 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x2F, 0x7F, 0xFF };
packet_header_default::packet_header_default(long header_len,
const std::string& len_tag_key,
const std::string& num_tag_key,
int bits_per_byte)
: d_header_len(header_len),
d_len_tag_key(pmt::string_to_symbol(len_tag_key)),
d_num_tag_key(num_tag_key.empty() ? pmt::PMT_NIL
: pmt::string_to_symbol(num_tag_key)),
d_bits_per_byte(bits_per_byte),
d_header_number(0)
{
if (d_bits_per_byte < 1 || d_bits_per_byte > 8) {
throw std::invalid_argument("bits_per_byte must be in [1, 8]");
}
d_mask = MASK_LUT[d_bits_per_byte];
}
packet_header_default::~packet_header_default() {}
bool packet_header_default::header_formatter(long packet_len,
unsigned char* out,
const std::vector<tag_t>& tags)
{
packet_len &= 0x0FFF;
d_crc_impl.reset();
d_crc_impl.process_bytes((void const*)&packet_len, 2);
d_crc_impl.process_bytes((void const*)&d_header_number, 2);
unsigned char crc = d_crc_impl();
memset(out, 0x00, d_header_len);
int k = 0; // Position in out
for (int i = 0; i < 12 && k < d_header_len; i += d_bits_per_byte, k++) {
out[k] = (unsigned char)((packet_len >> i) & d_mask);
}
for (int i = 0; i < 12 && k < d_header_len; i += d_bits_per_byte, k++) {
out[k] = (unsigned char)((d_header_number >> i) & d_mask);
}
for (int i = 0; i < 8 && k < d_header_len; i += d_bits_per_byte, k++) {
out[k] = (unsigned char)((crc >> i) & d_mask);
}
d_header_number++;
d_header_number &= 0x0FFF;
return true;
}
bool packet_header_default::header_parser(const unsigned char* in,
std::vector<tag_t>& tags)
{
unsigned header_len = 0;
unsigned header_num = 0;
tag_t tag;
int k = 0; // Position in "in"
for (int i = 0; i < 12 && k < d_header_len; i += d_bits_per_byte, k++) {
header_len |= (((int)in[k]) & d_mask) << i;
}
tag.key = d_len_tag_key;
tag.value = pmt::from_long(header_len);
tags.push_back(tag);
if (k >= d_header_len) {
return true;
}
if (d_num_tag_key == pmt::PMT_NIL) {
k += 12;
} else {
for (int i = 0; i < 12 && k < d_header_len; i += d_bits_per_byte, k++) {
header_num |= (((int)in[k]) & d_mask) << i;
}
tag.key = d_num_tag_key;
tag.value = pmt::from_long(header_num);
tags.push_back(tag);
}
if (k >= d_header_len) {
return true;
}
d_crc_impl.reset();
d_crc_impl.process_bytes((void const*)&header_len, 2);
d_crc_impl.process_bytes((void const*)&header_num, 2);
unsigned char crc_calcd = d_crc_impl();
for (int i = 0; i < 8 && k < d_header_len; i += d_bits_per_byte, k++) {
if ((((int)in[k]) & d_mask) != (((int)crc_calcd >> i) & d_mask)) {
return false;
}
}
return true;
}
} /* namespace digital */
} /* namespace gr */
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