247 lines
7.7 KiB
C++
247 lines
7.7 KiB
C++
/*
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* Copyright (C) 2015,2016 by Jonathan Naylor G4KLX
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Hamming.h"
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#include <cstdio>
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#include <cassert>
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// Hamming (15,11,3) check a boolean data array
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bool CHamming::decode15113(bool* d)
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{
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assert(d != NULL);
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// Calculate the checksum this row should have
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bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
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bool c1 = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
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bool c2 = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
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bool c3 = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
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unsigned char n = 0x00U;
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n |= (c0 != d[11]) ? 0x01U : 0x00U;
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n |= (c1 != d[12]) ? 0x02U : 0x00U;
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n |= (c2 != d[13]) ? 0x04U : 0x00U;
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n |= (c3 != d[14]) ? 0x08U : 0x00U;
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switch (n) {
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// Parity bit errors
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case 0x01U: d[11] = !d[11]; return true;
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case 0x02U: d[12] = !d[12]; return true;
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case 0x04U: d[13] = !d[13]; return true;
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case 0x08U: d[14] = !d[14]; return true;
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// Data bit errors
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case 0x09U: d[0] = !d[0]; return true;
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case 0x0BU: d[1] = !d[1]; return true;
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case 0x0FU: d[2] = !d[2]; return true;
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case 0x07U: d[3] = !d[3]; return true;
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case 0x0EU: d[4] = !d[4]; return true;
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case 0x05U: d[5] = !d[5]; return true;
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case 0x0AU: d[6] = !d[6]; return true;
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case 0x0DU: d[7] = !d[7]; return true;
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case 0x03U: d[8] = !d[8]; return true;
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case 0x06U: d[9] = !d[9]; return true;
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case 0x0CU: d[10] = !d[10]; return true;
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// No bit errors
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default: return false;
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}
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}
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void CHamming::encode15113(bool* d)
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{
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assert(d != NULL);
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// Calculate the checksum this row should have
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d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
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d[12] = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
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d[13] = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
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d[14] = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
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}
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// Hamming (13,9,3) check a boolean data array
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bool CHamming::decode1393(bool* d)
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{
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assert(d != NULL);
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// Calculate the checksum this column should have
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bool c0 = d[0] ^ d[1] ^ d[3] ^ d[5] ^ d[6];
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bool c1 = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7];
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bool c2 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
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bool c3 = d[0] ^ d[2] ^ d[4] ^ d[5] ^ d[8];
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unsigned char n = 0x00U;
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n |= (c0 != d[9]) ? 0x01U : 0x00U;
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n |= (c1 != d[10]) ? 0x02U : 0x00U;
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n |= (c2 != d[11]) ? 0x04U : 0x00U;
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n |= (c3 != d[12]) ? 0x08U : 0x00U;
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switch (n) {
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// Parity bit errors
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case 0x01U: d[9] = !d[9]; return true;
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case 0x02U: d[10] = !d[10]; return true;
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case 0x04U: d[11] = !d[11]; return true;
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case 0x08U: d[12] = !d[12]; return true;
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// Data bit erros
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case 0x0FU: d[0] = !d[0]; return true;
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case 0x07U: d[1] = !d[1]; return true;
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case 0x0EU: d[2] = !d[2]; return true;
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case 0x05U: d[3] = !d[3]; return true;
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case 0x0AU: d[4] = !d[4]; return true;
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case 0x0DU: d[5] = !d[5]; return true;
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case 0x03U: d[6] = !d[6]; return true;
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case 0x06U: d[7] = !d[7]; return true;
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case 0x0CU: d[8] = !d[8]; return true;
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// No bit errors
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default: return false;
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}
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}
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void CHamming::encode1393(bool* d)
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{
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assert(d != NULL);
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// Calculate the checksum this column should have
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d[9] = d[0] ^ d[1] ^ d[3] ^ d[5] ^ d[6];
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d[10] = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7];
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d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
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d[12] = d[0] ^ d[2] ^ d[4] ^ d[5] ^ d[8];
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}
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// A Hamming (16,11,4) Check
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bool CHamming::decode16114(bool* d)
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{
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assert(d != NULL);
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// Calculate the checksum this column should have
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bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
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bool c1 = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
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bool c2 = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
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bool c3 = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
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bool c4 = d[0] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[9] ^ d[10];
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// Compare these with the actual bits
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unsigned char n = 0x00U;
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n |= (c0 != d[11]) ? 0x01U : 0x00U;
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n |= (c1 != d[12]) ? 0x02U : 0x00U;
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n |= (c2 != d[13]) ? 0x04U : 0x00U;
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n |= (c3 != d[14]) ? 0x08U : 0x00U;
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n |= (c4 != d[15]) ? 0x10U : 0x00U;
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switch (n) {
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// Parity bit errors
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case 0x01U: d[11] = !d[11]; return true;
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case 0x02U: d[12] = !d[12]; return true;
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case 0x04U: d[13] = !d[13]; return true;
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case 0x08U: d[14] = !d[14]; return true;
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case 0x10U: d[15] = !d[15]; return true;
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// Data bit errors
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case 0x19U: d[0] = !d[0]; return true;
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case 0x0BU: d[1] = !d[1]; return true;
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case 0x1FU: d[2] = !d[2]; return true;
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case 0x07U: d[3] = !d[3]; return true;
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case 0x0EU: d[4] = !d[4]; return true;
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case 0x15U: d[5] = !d[5]; return true;
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case 0x1AU: d[6] = !d[6]; return true;
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case 0x0DU: d[7] = !d[7]; return true;
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case 0x13U: d[8] = !d[8]; return true;
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case 0x16U: d[9] = !d[9]; return true;
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case 0x1CU: d[10] = !d[10]; return true;
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// No bit errors
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case 0x00U: return true;
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// Unrecoverable errors
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default: return false;
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}
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}
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void CHamming::encode16114(bool* d)
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{
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assert(d != NULL);
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d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[5] ^ d[7] ^ d[8];
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d[12] = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[6] ^ d[8] ^ d[9];
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d[13] = d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[7] ^ d[9] ^ d[10];
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d[14] = d[0] ^ d[1] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[10];
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d[15] = d[0] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[9] ^ d[10];
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}
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// A Hamming (17,12,3) Check
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bool CHamming::decode17123(bool* d)
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{
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assert(d != NULL);
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// Calculate the checksum this column should have
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bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[6] ^ d[7] ^ d[9];
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bool c1 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[7] ^ d[8] ^ d[10];
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bool c2 = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[8] ^ d[9] ^ d[11];
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bool c3 = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[10];
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bool c4 = d[0] ^ d[1] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[11];
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// Compare these with the actual bits
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unsigned char n = 0x00U;
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n |= (c0 != d[12]) ? 0x01U : 0x00U;
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n |= (c1 != d[13]) ? 0x02U : 0x00U;
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n |= (c2 != d[14]) ? 0x04U : 0x00U;
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n |= (c3 != d[15]) ? 0x08U : 0x00U;
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n |= (c4 != d[16]) ? 0x10U : 0x00U;
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switch (n) {
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// Parity bit errors
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case 0x01U: d[12] = !d[12]; return true;
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case 0x02U: d[13] = !d[13]; return true;
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case 0x04U: d[14] = !d[14]; return true;
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case 0x08U: d[15] = !d[15]; return true;
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case 0x10U: d[16] = !d[16]; return true;
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// Data bit errors
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case 0x1BU: d[0] = !d[0]; return true;
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case 0x1FU: d[1] = !d[1]; return true;
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case 0x17U: d[2] = !d[2]; return true;
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case 0x07U: d[3] = !d[3]; return true;
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case 0x0EU: d[4] = !d[4]; return true;
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case 0x1CU: d[5] = !d[5]; return true;
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case 0x11U: d[6] = !d[6]; return true;
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case 0x0BU: d[7] = !d[7]; return true;
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case 0x16U: d[8] = !d[8]; return true;
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case 0x05U: d[9] = !d[9]; return true;
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case 0x0AU: d[10] = !d[10]; return true;
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case 0x14U: d[11] = !d[11]; return true;
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// No bit errors
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case 0x00U: return true;
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// Unrecoverable errors
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default: return false;
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}
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}
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void CHamming::encode17123(bool* d)
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{
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assert(d != NULL);
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d[12] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[6] ^ d[7] ^ d[9];
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d[13] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[7] ^ d[8] ^ d[10];
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d[14] = d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[8] ^ d[9] ^ d[11];
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d[15] = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[10];
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d[16] = d[0] ^ d[1] ^ d[2] ^ d[5] ^ d[6] ^ d[8] ^ d[11];
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}
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