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/* -*- c++ -*- */
/*
* Copyright 2015,2016 Free Software Foundation, Inc.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "dvbt_symbol_inner_interleaver_impl.h"
#include <gnuradio/io_signature.h>
namespace gr {
namespace dtv {
const char dvbt_symbol_inner_interleaver_impl::d_bit_perm_2k[] = { 4, 3, 9, 6, 2,
8, 1, 5, 7, 0 };
const char dvbt_symbol_inner_interleaver_impl::d_bit_perm_8k[] = { 7, 1, 4, 2, 9, 6,
8, 10, 0, 3, 11, 5 };
void dvbt_symbol_inner_interleaver_impl::generate_H()
{
const int Mmax = d_fft_length;
const int Nmax = d_payload_length;
const int Nr = int(ceil(log2(d_fft_length)));
int q = 0;
for (int i = 0; i < Mmax; i++) {
d_h[q] = ((i % 2) << (Nr - 1)) + calculate_R(i);
if (d_h[q] < Nmax) {
q++;
}
}
}
int dvbt_symbol_inner_interleaver_impl::H(int q) { return d_h[q]; }
int dvbt_symbol_inner_interleaver_impl::calculate_R(int i)
{
const int Nr = int(ceil(log2(d_fft_length)));
int reg = 0;
if (i == 0) {
reg = 0;
} else if (i == 1) {
reg = 0;
} else {
reg = 1;
for (int k = 3; k <= i; k++) {
char new_bit = 0;
if (d_transmission_mode == T2k) {
new_bit = (reg ^ (reg >> 3)) & 1;
} else if (d_transmission_mode == T8k) {
new_bit = (reg ^ (reg >> 1) ^ (reg >> 4) ^ (reg >> 6)) & 1;
} else {
new_bit = (reg ^ (reg >> 3)) & 1;
}
int mask = (1 << Nr) - 1;
reg = ((reg >> 1) | (new_bit << (Nr - 2))) & mask;
}
}
int newreg = 0;
for (int k = 0; k < (Nr - 1); k++) {
char bit = (reg >> k) & 1;
newreg = newreg | (bit << d_bit_perm[k]);
}
return newreg;
}
dvbt_symbol_inner_interleaver::sptr dvbt_symbol_inner_interleaver::make(
int nsize, dvbt_transmission_mode_t transmission, int direction)
{
return gnuradio::make_block_sptr<dvbt_symbol_inner_interleaver_impl>(
nsize, transmission, direction);
}
/*
* The private constructor
*/
dvbt_symbol_inner_interleaver_impl::dvbt_symbol_inner_interleaver_impl(
int nsize, dvbt_transmission_mode_t transmission, int direction)
: block("dvbt_symbol_inner_interleaver",
io_signature::make(1, 1, sizeof(unsigned char) * nsize),
io_signature::make(1, 1, sizeof(unsigned char) * nsize)),
config(gr::dtv::MOD_16QAM,
gr::dtv::NH,
gr::dtv::C1_2,
gr::dtv::C1_2,
gr::dtv::GI_1_32,
transmission),
d_nsize(nsize),
d_direction(direction),
d_fft_length(0),
d_payload_length(0),
d_symbol_index(0)
{
d_symbols_per_frame = config.d_symbols_per_frame;
d_transmission_mode = config.d_transmission_mode;
d_fft_length = config.d_fft_length;
d_payload_length = config.d_payload_length;
d_direction = direction;
// Verify if transmission mode matches with size of block
assert(d_payload_length == d_nsize);
// Allocate memory for h vector
d_h = new (std::nothrow) int[d_fft_length];
if (d_h == NULL) {
GR_LOG_FATAL(d_logger,
"Symbol Inner Interleaver, cannot allocate memory for d_h.");
throw std::bad_alloc();
}
// Setup bit permutation vectors
if (d_transmission_mode == T2k) {
d_bit_perm = d_bit_perm_2k;
} else if (d_transmission_mode == T8k) {
d_bit_perm = d_bit_perm_8k;
} else {
d_bit_perm = d_bit_perm_2k;
}
// Generate the h function
generate_H();
}
/*
* Our virtual destructor.
*/
dvbt_symbol_inner_interleaver_impl::~dvbt_symbol_inner_interleaver_impl()
{
delete[] d_h;
}
void dvbt_symbol_inner_interleaver_impl::forecast(int noutput_items,
gr_vector_int& ninput_items_required)
{
ninput_items_required[0] = noutput_items;
}
int dvbt_symbol_inner_interleaver_impl::general_work(
int noutput_items,
gr_vector_int& ninput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items)
{
const unsigned char* in = (unsigned char*)input_items[0];
unsigned char* out = (unsigned char*)output_items[0];
// Demod reference signals sends a tag per OFDM frame
// containing the symbol index.
std::vector<tag_t> tags;
const uint64_t nread = this->nitems_read(0); // number of items read on port 0
// Read all tags on the input buffer
this->get_tags_in_range(
tags, 0, nread, nread + noutput_items, pmt::string_to_symbol("symbol_index"));
for (int k = 0; k < noutput_items; k++) {
int blocks = k * d_nsize;
if (d_direction) {
// Interleave
for (int q = 0; q < d_nsize; q++) {
if (d_symbol_index % 2) {
out[blocks + q] = in[blocks + H(q)];
} else {
out[blocks + H(q)] = in[blocks + q];
}
}
++d_symbol_index;
d_symbol_index = d_symbol_index % d_symbols_per_frame;
} else {
// Deinterleave
d_symbol_index = pmt::to_long(tags[k].value);
for (int q = 0; q < d_nsize; q++) {
if (d_symbol_index % 2) {
out[blocks + H(q)] = in[blocks + q];
} else {
out[blocks + q] = in[blocks + H(q)];
}
}
}
}
// Tell runtime system how many input items we consumed on
// each input stream.
consume_each(noutput_items);
// Tell runtime system how many output items we produced.
return noutput_items;
}
} /* namespace dtv */
} /* namespace gr */
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