/**
* Digital Voice Modem - Host Software
* GPLv2 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* @package DVM / Host Software
*
*/
//
// Based on code from the MMDVMHost project. (https://github.com/g4klx/MMDVMHost)
// Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
//
/*
*   Copyright (C) 2015,2016 by Jonathan Naylor G4KLX
*
*   This program 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 2 of the License, or
*   (at your option) any later version.
*
*   This program 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 this program; if not, write to the Free Software
*   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "edac/Hamming.h"

using namespace edac;

#include <cstdio>
#include <cassert>

// ---------------------------------------------------------------------------
//  Static Class Members
// ---------------------------------------------------------------------------
/// <summary>
/// Decode Hamming (15,11,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
/// <returns>True, if bit errors are detected, otherwise false.</returns>
bool Hamming::decode15113_1(bool* d)
{
    assert(d != NULL);

    // Calculate the parity it should have
    bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[6];
    bool c1 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[7] ^ d[8] ^ d[9];
    bool c2 = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[8] ^ d[10];
    bool c3 = d[0] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[9] ^ d[10];

    unsigned char n = 0U;
    n |= (c0 != d[11]) ? 0x01U : 0x00U;
    n |= (c1 != d[12]) ? 0x02U : 0x00U;
    n |= (c2 != d[13]) ? 0x04U : 0x00U;
    n |= (c3 != d[14]) ? 0x08U : 0x00U;

    switch (n) {
        // Parity bit errors
        case 0x01U: d[11] = !d[11]; return true;
        case 0x02U: d[12] = !d[12]; return true;
        case 0x04U: d[13] = !d[13]; return true;
        case 0x08U: d[14] = !d[14]; return true;

        // Data bit errors
        case 0x0FU: d[0] = !d[0];  return true;
        case 0x07U: d[1] = !d[1];  return true;
        case 0x0BU: d[2] = !d[2];  return true;
        case 0x03U: d[3] = !d[3];  return true;
        case 0x0DU: d[4] = !d[4];  return true;
        case 0x05U: d[5] = !d[5];  return true;
        case 0x09U: d[6] = !d[6];  return true;
        case 0x0EU: d[7] = !d[7];  return true;
        case 0x06U: d[8] = !d[8];  return true;
        case 0x0AU: d[9] = !d[9];  return true;
        case 0x0CU: d[10] = !d[10]; return true;

        // No bit errors
        default: return false;
    }
}

/// <summary>
/// Encode Hamming (15,11,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
void Hamming::encode15113_1(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this row should have
    d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[6];
    d[12] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[7] ^ d[8] ^ d[9];
    d[13] = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[8] ^ d[10];
    d[14] = d[0] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[9] ^ d[10];
}

/// <summary>
/// Decode Hamming (15,11,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
/// <returns>True, if bit errors are detected, otherwise false.</returns>
bool Hamming::decode15113_2(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this row should have
    bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
    bool c1 = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
    bool c2 = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
    bool c3 = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];

    unsigned char n = 0x00U;
    n |= (c0 != d[11]) ? 0x01U : 0x00U;
    n |= (c1 != d[12]) ? 0x02U : 0x00U;
    n |= (c2 != d[13]) ? 0x04U : 0x00U;
    n |= (c3 != d[14]) ? 0x08U : 0x00U;

    switch (n) {
        // Parity bit errors
        case 0x01U: d[11] = !d[11]; return true;
        case 0x02U: d[12] = !d[12]; return true;
        case 0x04U: d[13] = !d[13]; return true;
        case 0x08U: d[14] = !d[14]; return true;

        // Data bit errors
        case 0x09U: d[0] = !d[0];  return true;
        case 0x0BU: d[1] = !d[1];  return true;
        case 0x0FU: d[2] = !d[2];  return true;
        case 0x07U: d[3] = !d[3];  return true;
        case 0x0EU: d[4] = !d[4];  return true;
        case 0x05U: d[5] = !d[5];  return true;
        case 0x0AU: d[6] = !d[6];  return true;
        case 0x0DU: d[7] = !d[7];  return true;
        case 0x03U: d[8] = !d[8];  return true;
        case 0x06U: d[9] = !d[9];  return true;
        case 0x0CU: d[10] = !d[10]; return true;

        // No bit errors
        default: return false;
    }
}

/// <summary>
/// Encode Hamming (15,11,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
void Hamming::encode15113_2(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this row should have
    d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
    d[12] = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
    d[13] = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
    d[14] = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
}

/// <summary>
/// Decode Hamming (13,9,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
/// <returns>True, if bit errors are detected, otherwise false.</returns>
bool Hamming::decode1393(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this column should have
    bool c0 = d[0] ^ d[1] ^ d[3] ^ d[5] ^ d[6];
    bool c1 = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7];
    bool c2 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
    bool c3 = d[0] ^ d[2] ^ d[4] ^ d[5] ^ d[8];

    unsigned char n = 0x00U;
    n |= (c0 != d[9]) ? 0x01U : 0x00U;
    n |= (c1 != d[10]) ? 0x02U : 0x00U;
    n |= (c2 != d[11]) ? 0x04U : 0x00U;
    n |= (c3 != d[12]) ? 0x08U : 0x00U;

    switch (n) {
        // Parity bit errors
        case 0x01U: d[9] = !d[9];  return true;
        case 0x02U: d[10] = !d[10]; return true;
        case 0x04U: d[11] = !d[11]; return true;
        case 0x08U: d[12] = !d[12]; return true;

        // Data bit erros
        case 0x0FU: d[0] = !d[0]; return true;
        case 0x07U: d[1] = !d[1]; return true;
        case 0x0EU: d[2] = !d[2]; return true;
        case 0x05U: d[3] = !d[3]; return true;
        case 0x0AU: d[4] = !d[4]; return true;
        case 0x0DU: d[5] = !d[5]; return true;
        case 0x03U: d[6] = !d[6]; return true;
        case 0x06U: d[7] = !d[7]; return true;
        case 0x0CU: d[8] = !d[8]; return true;

        // No bit errors
        default: return false;
    }
}

/// <summary>
/// Encode Hamming (13,9,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
void Hamming::encode1393(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this column should have
    d[9] = d[0] ^ d[1] ^ d[3] ^ d[5] ^ d[6];
    d[10] = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7];
    d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
    d[12] = d[0] ^ d[2] ^ d[4] ^ d[5] ^ d[8];
}

/// <summary>
/// Decode Hamming (10,6,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
/// <returns>True, if bit errors are detected, otherwise false.</returns>
bool Hamming::decode1063(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this column should have
    bool c0 = d[0] ^ d[1] ^ d[2] ^ d[5];
    bool c1 = d[0] ^ d[1] ^ d[3] ^ d[5];
    bool c2 = d[0] ^ d[2] ^ d[3] ^ d[4];
    bool c3 = d[1] ^ d[2] ^ d[3] ^ d[4];

    unsigned char n = 0x00U;
    n |= (c0 != d[6]) ? 0x01U : 0x00U;
    n |= (c1 != d[7]) ? 0x02U : 0x00U;
    n |= (c2 != d[8]) ? 0x04U : 0x00U;
    n |= (c3 != d[9]) ? 0x08U : 0x00U;

    switch (n) {
        // Parity bit errors
        case 0x01U: d[6] = !d[6]; return true;
        case 0x02U: d[7] = !d[7]; return true;
        case 0x04U: d[8] = !d[8]; return true;
        case 0x08U: d[9] = !d[9]; return true;

        // Data bit erros
        case 0x07U: d[0] = !d[0]; return true;
        case 0x0BU: d[1] = !d[1]; return true;
        case 0x0DU: d[2] = !d[2]; return true;
        case 0x0EU: d[3] = !d[3]; return true;
        case 0x0CU: d[4] = !d[4]; return true;
        case 0x03U: d[5] = !d[5]; return true;

        // No bit errors
        default: return false;
    }
}

/// <summary>
/// Encode Hamming (10,6,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
void Hamming::encode1063(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this column should have
    d[6] = d[0] ^ d[1] ^ d[2] ^ d[5];
    d[7] = d[0] ^ d[1] ^ d[3] ^ d[5];
    d[8] = d[0] ^ d[2] ^ d[3] ^ d[4];
    d[9] = d[1] ^ d[2] ^ d[3] ^ d[4];
}

/// <summary>
/// Decode Hamming (16,11,4).
/// </summary>
/// <param name="d">Boolean bit array.</param>
/// <returns>True, if bit errors are detected or no bit errors, otherwise false if unrecoverable errors are detected.</returns>
bool Hamming::decode16114(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this column should have
    bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
    bool c1 = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
    bool c2 = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
    bool c3 = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
    bool c4 = d[0] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[9] ^ d[10];

    // Compare these with the actual bits
    unsigned char n = 0x00U;
    n |= (c0 != d[11]) ? 0x01U : 0x00U;
    n |= (c1 != d[12]) ? 0x02U : 0x00U;
    n |= (c2 != d[13]) ? 0x04U : 0x00U;
    n |= (c3 != d[14]) ? 0x08U : 0x00U;
    n |= (c4 != d[15]) ? 0x10U : 0x00U;

    switch (n) {
        // Parity bit errors
        case 0x01U: d[11] = !d[11]; return true;
        case 0x02U: d[12] = !d[12]; return true;
        case 0x04U: d[13] = !d[13]; return true;
        case 0x08U: d[14] = !d[14]; return true;
        case 0x10U: d[15] = !d[15]; return true;

        // Data bit errors
        case 0x19U: d[0] = !d[0];  return true;
        case 0x0BU: d[1] = !d[1];  return true;
        case 0x1FU: d[2] = !d[2];  return true;
        case 0x07U: d[3] = !d[3];  return true;
        case 0x0EU: d[4] = !d[4];  return true;
        case 0x15U: d[5] = !d[5];  return true;
        case 0x1AU: d[6] = !d[6];  return true;
        case 0x0DU: d[7] = !d[7];  return true;
        case 0x13U: d[8] = !d[8];  return true;
        case 0x16U: d[9] = !d[9];  return true;
        case 0x1CU: d[10] = !d[10]; return true;

        // No bit errors
        case 0x00U: return true;

        // Unrecoverable errors
        default: return false;
    }
}

/// <summary>
/// Encode Hamming (10,6,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
void Hamming::encode16114(bool* d)
{
    assert(d != NULL);

    d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
    d[12] = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
    d[13] = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
    d[14] = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
    d[15] = d[0] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[9] ^ d[10];
}

/// <summary>
/// Decode Hamming (17,12,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
/// <returns>True, if bit errors are detected or no bit errors, otherwise false if unrecoverable errors are detected.</returns>
bool Hamming::decode17123(bool* d)
{
    assert(d != NULL);

    // Calculate the checksum this column should have
    bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[6] ^ d[7] ^ d[9];
    bool c1 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[7] ^ d[8] ^ d[10];
    bool c2 = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[8] ^ d[9] ^ d[11];
    bool c3 = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[10];
    bool c4 = d[0] ^ d[1] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[11];

    // Compare these with the actual bits
    unsigned char n = 0x00U;
    n |= (c0 != d[12]) ? 0x01U : 0x00U;
    n |= (c1 != d[13]) ? 0x02U : 0x00U;
    n |= (c2 != d[14]) ? 0x04U : 0x00U;
    n |= (c3 != d[15]) ? 0x08U : 0x00U;
    n |= (c4 != d[16]) ? 0x10U : 0x00U;

    switch (n) {
        // Parity bit errors
        case 0x01U: d[12] = !d[12]; return true;
        case 0x02U: d[13] = !d[13]; return true;
        case 0x04U: d[14] = !d[14]; return true;
        case 0x08U: d[15] = !d[15]; return true;
        case 0x10U: d[16] = !d[16]; return true;

        // Data bit errors
        case 0x1BU: d[0] = !d[0];  return true;
        case 0x1FU: d[1] = !d[1];  return true;
        case 0x17U: d[2] = !d[2];  return true;
        case 0x07U: d[3] = !d[3];  return true;
        case 0x0EU: d[4] = !d[4];  return true;
        case 0x1CU: d[5] = !d[5];  return true;
        case 0x11U: d[6] = !d[6];  return true;
        case 0x0BU: d[7] = !d[7];  return true;
        case 0x16U: d[8] = !d[8];  return true;
        case 0x05U: d[9] = !d[9];  return true;
        case 0x0AU: d[10] = !d[10]; return true;
        case 0x14U: d[11] = !d[11]; return true;

        // No bit errors
        case 0x00U: return true;

        // Unrecoverable errors
        default: return false;
    }
}

/// <summary>
/// Encode Hamming (17,12,3).
/// </summary>
/// <param name="d">Boolean bit array.</param>
void Hamming::encode17123(bool* d)
{
    assert(d != NULL);

    d[12] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[6] ^ d[7] ^ d[9];
    d[13] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[7] ^ d[8] ^ d[10];
    d[14] = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[8] ^ d[9] ^ d[11];
    d[15] = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[10];
    d[16] = d[0] ^ d[1] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[11];
}