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/* -*- c++ -*- */
/* Copyright 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/packet_header_default.h>
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::pmt_string_to_symbol(len_tag_key)),
d_num_tag_key(pmt::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<gr_tag_t> &tags
)
{
packet_len &= 0x0FFF;
memset(out, 0x00, d_header_len);
int parity = 0;
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);
parity += out[k];
}
for (int i = 0; i < 16 && k < d_header_len; i += d_bits_per_byte, k++) {
out[k] = (unsigned char) ((d_header_number >> i) & d_mask);
parity += out[k];
}
if (k < d_header_len) {
out[k] = (unsigned char) (parity % 2);
}
d_header_number++;
return true;
}
bool packet_header_default::header_parser(
const unsigned char *in,
std::vector<gr_tag_t> &tags)
{
unsigned header_len = 0;
unsigned header_num = 0;
gr_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::pmt_from_long(header_len);
tags.push_back(tag);
if (k >= d_header_len) {
return true;
}
for (int i = 0; i < 16 && 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::pmt_from_long(header_num);
tags.push_back(tag);
if (k >= d_header_len) {
return true;
}
int parity = in[k];
for (int i = 0; i < 28; i++) {
parity += in[i];
}
return !(parity % 2);
}
} /* namespace digital */
} /* namespace gr */
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