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/* -*- c++ -*- */
/*
* Copyright 2016,2017 Free Software Foundation, Inc.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "catv_randomizer_bb_impl.h"
#include <gnuradio/io_signature.h>
namespace gr {
namespace dtv {
catv_randomizer_bb::sptr catv_randomizer_bb::make(catv_constellation_t constellation)
{
return gnuradio::get_initial_sptr(new catv_randomizer_bb_impl(constellation));
}
/*
* The private constructor
*/
catv_randomizer_bb_impl::catv_randomizer_bb_impl(catv_constellation_t constellation)
: gr::sync_block("catv_randomizer_bb",
gr::io_signature::make(1, 1, sizeof(unsigned char)),
gr::io_signature::make(1, 1, sizeof(unsigned char)))
{
offset = 0;
if (constellation == CATV_MOD_64QAM) {
max_offset = 60 * 128;
} else {
max_offset = 88 * 128;
}
init_rand();
}
/*
* Our virtual destructor.
*/
catv_randomizer_bb_impl::~catv_randomizer_bb_impl() {}
void catv_randomizer_bb_impl::init_rand()
{
unsigned char c2 = 0x7F, c1 = 0x7F, c0 = 0x7F;
unsigned char c2_new, c1_new, c0_new;
int n, i;
for (n = 0; n < max_offset; n++) {
rseq[n] = c2;
c2_new = c1;
c1_new = c0 ^ c2;
c0_new = c2;
for (i = 0; i < 3; i++) {
c0_new <<= 1;
if (c0_new & 0x80) {
c0_new = (c0_new & 0x7F) ^ 0x09;
}
}
c2 = c2_new;
c1 = c1_new;
c0 = c0_new;
}
}
int catv_randomizer_bb_impl::work(int noutput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items)
{
const unsigned char* in = (const unsigned char*)input_items[0];
unsigned char* out = (unsigned char*)output_items[0];
for (int i = 0; i < noutput_items; i++) {
out[i] = in[i] ^ rseq[offset++];
if (offset == max_offset) {
offset = 0;
}
}
// Tell runtime system how many output items we produced.
return noutput_items;
}
} /* namespace dtv */
} /* namespace gr */
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