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/* -*- c++ -*- */
/*
* Copyright 2016 Free Software Foundation, Inc.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "catv_reed_solomon_enc_bb_impl.h"
#include <gnuradio/io_signature.h>
namespace gr {
namespace dtv {
catv_reed_solomon_enc_bb::sptr catv_reed_solomon_enc_bb::make()
{
return gnuradio::get_initial_sptr(new catv_reed_solomon_enc_bb_impl());
}
/*
* The private constructor
*/
catv_reed_solomon_enc_bb_impl::catv_reed_solomon_enc_bb_impl()
: gr::block("catv_reed_solomon_enc_bb",
gr::io_signature::make(1, 1, sizeof(unsigned char)),
gr::io_signature::make(1, 1, sizeof(unsigned char)))
{
set_output_multiple(128);
init_rs();
}
/*
* Our virtual destructor.
*/
catv_reed_solomon_enc_bb_impl::~catv_reed_solomon_enc_bb_impl() {}
void catv_reed_solomon_enc_bb_impl::init_rs()
{
unsigned char x;
int i, j;
gf_exp[0] = 1;
gf_log[1] = 0;
x = 1;
for (i = 1; i < 127; i++) {
x <<= 1;
if (x & 0x80) {
x = (x & 0x7F) ^ 0x09;
}
gf_exp[i] = x;
gf_log[x] = i;
}
for (; i < 256; i++) {
gf_exp[i] = gf_exp[i - 127];
}
for (i = 0; i < 128; i++) {
for (j = 0; j < 128; j++) {
if ((i == 0) || (j == 0)) {
gf_mul_table[i][j] = 0;
} else {
gf_mul_table[i][j] = gf_exp[gf_log[i] + gf_log[j]];
}
}
}
}
unsigned char
catv_reed_solomon_enc_bb_impl::gf_poly_eval(unsigned char* p, int len, unsigned char x)
{
unsigned char y = p[0];
int i;
for (i = 1; i < len; i++) {
y = gf_mul_table[y][x] ^ p[i];
}
return y;
}
void catv_reed_solomon_enc_bb_impl::reed_solomon_enc(const unsigned char* message,
unsigned char* output)
{
// Generator polynomial from p.7 of ANSI/SCTE 07 2013
unsigned char g[] = {
1, gf_exp[52], gf_exp[116], gf_exp[119], gf_exp[61], gf_exp[15]
};
int i, j;
memcpy(output, message, 122);
memset(output + 122, 0, 6);
for (i = 0; i < 122; i++) {
for (j = 1; j < 6; j++) {
output[i + j] ^= gf_mul_table[output[i]][g[j]];
}
output[i] = message[i];
}
output[127] = gf_poly_eval(output, 127, gf_exp[6]);
}
void catv_reed_solomon_enc_bb_impl::forecast(int noutput_items,
gr_vector_int& ninput_items_required)
{
ninput_items_required[0] = (noutput_items / 128) * 122;
}
int catv_reed_solomon_enc_bb_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 = (const unsigned char*)input_items[0];
unsigned char* out = (unsigned char*)output_items[0];
int j = 0;
for (int i = 0; i < noutput_items; i += 128) {
reed_solomon_enc(in + j, out + i);
j += 122;
}
// Tell runtime system how many input items we consumed on
// each input stream.
consume_each(j);
// Tell runtime system how many output items we produced.
return noutput_items;
}
} /* namespace dtv */
} /* namespace gr */
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