/* -*- c++ -*- */
/*
 * Copyright 2015 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */

#include <gnuradio/fec/cldpc.h>
#include <stdexcept>

cldpc::cldpc(const GF2Mat X)
{
    H = X;
    M = H.get_M();
    N = H.get_N();
    G = H.get_G(permute, rank_H);
    K = N - rank_H;
}

cldpc::cldpc(const alist _list)
{
    H = GF2Mat(_list);
    M = H.get_M();
    N = H.get_N();
    G = H.get_G(permute, rank_H);
    K = N - rank_H;
}

void cldpc::set_alist(const alist _list)
{
    H = GF2Mat(_list);
    M = H.get_M();
    N = H.get_N();
    G = H.get_G(permute, rank_H);
    K = N - rank_H;
}

std::vector<uint8_t> cldpc::get_systematic_bits(std::vector<uint8_t> in)
{
    std::vector<uint8_t> data;
    data.resize(K);
    int index;
    for (size_t i = 0; i < K; i++) {
        index = permute[i + rank_H];
        data[i] = in[index];
    }
    return data;
}

void cldpc::print_permute()
{
    for (size_t i = 0; i < permute.size(); i++) {
        std::cout << permute[i] << ", ";
    }
    std::cout << "\n";
}

std::vector<uint8_t> cldpc::syndrome(const std::vector<uint8_t> in)
{
    std::vector<uint8_t> synd;
    synd.resize(rank_H);
    GF2Vec in_bvec;
    in_bvec.set_vec(in);
    for (int i = 0; i < rank_H; i++) {
        synd[i] = H[i] * in_bvec;
    }
    return synd;
}

bool cldpc::is_codeword(const std::vector<uint8_t> in)
{
    std::vector<uint8_t> synd;
    synd = syndrome(in);
    bool is_code;
    is_code = true;
    for (int i = 0; i < rank_H; i++) {
        if (synd[i] != char(0)) {
            is_code = false;
        }
    }
    return is_code;
}

std::vector<uint8_t> cldpc::encode(std::vector<uint8_t> dataword)
{
    if (dataword.size() == K) {
        GF2Vec x(N);
        GF2Vec data(K);
        data.set_vec(dataword);
        for (int i = rank_H; i < N; i++) {
            x[i] = dataword[i - rank_H];
        }
        for (int i = 0; i < rank_H; i++) {
            x[i] = G[i].sub_vector(N - K, N) * data;
        }
        GF2Vec y(N);
        for (int i = 0; i < N; i++) {
            y[permute[i]] = x[i];
        }
        return y.get_vec();
    } else {
        throw std::runtime_error("bad vector length!");
        return std::vector<uint8_t>();
    }
}

int cldpc::dimension() { return K; }

int cldpc::get_M() { return M; }

int cldpc::get_N() { return N; }

GF2Mat cldpc::get_H() { return H; }

GF2Mat cldpc::get_G() { return G; }
