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371 lines
10 KiB
C++
371 lines
10 KiB
C++
/*
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* Copyright (C) 2012 by Ian Wraith
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* Copyright (C) 2015 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 "cbptc19696.h"
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#include "chamming.h"
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//#include "cutils.h"
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#include <cstdio>
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#include <cassert>
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#include <cstring>
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CBPTC19696::CBPTC19696()
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{
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}
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CBPTC19696::~CBPTC19696()
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{
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}
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// The main decode function
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void CBPTC19696::decode(const uint8_t* in, uint8_t* out)
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{
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assert(in != NULL);
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assert(out != NULL);
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// Get the raw binary
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decodeExtractBinary(in);
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// Deinterleave
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decodeDeInterleave();
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// Error check
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decodeErrorCheck();
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// Extract Data
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decodeExtractData(out);
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}
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// The main encode function
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void CBPTC19696::encode(const uint8_t* in, uint8_t* out)
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{
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assert(in != NULL);
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assert(out != NULL);
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// Extract Data
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encodeExtractData(in);
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// Error check
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encodeErrorCheck();
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// Deinterleave
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encodeInterleave();
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// Get the raw binary
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encodeExtractBinary(out);
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}
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void CBPTC19696::byteToBitsBE(uint8_t byte, bool* bits)
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{
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assert(bits != NULL);
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bits[0U] = (byte & 0x80U) == 0x80U;
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bits[1U] = (byte & 0x40U) == 0x40U;
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bits[2U] = (byte & 0x20U) == 0x20U;
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bits[3U] = (byte & 0x10U) == 0x10U;
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bits[4U] = (byte & 0x08U) == 0x08U;
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bits[5U] = (byte & 0x04U) == 0x04U;
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bits[6U] = (byte & 0x02U) == 0x02U;
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bits[7U] = (byte & 0x01U) == 0x01U;
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}
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void CBPTC19696::bitsToByteBE(bool* bits, uint8_t& byte)
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{
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assert(bits != NULL);
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byte = bits[0U] ? 0x80U : 0x00U;
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byte |= bits[1U] ? 0x40U : 0x00U;
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byte |= bits[2U] ? 0x20U : 0x00U;
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byte |= bits[3U] ? 0x10U : 0x00U;
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byte |= bits[4U] ? 0x08U : 0x00U;
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byte |= bits[5U] ? 0x04U : 0x00U;
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byte |= bits[6U] ? 0x02U : 0x00U;
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byte |= bits[7U] ? 0x01U : 0x00U;
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}
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void CBPTC19696::decodeExtractBinary(const uint8_t* in)
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{
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// First block
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byteToBitsBE(in[0U], m_rawData + 0U);
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byteToBitsBE(in[1U], m_rawData + 8U);
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byteToBitsBE(in[2U], m_rawData + 16U);
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byteToBitsBE(in[3U], m_rawData + 24U);
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byteToBitsBE(in[4U], m_rawData + 32U);
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byteToBitsBE(in[5U], m_rawData + 40U);
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byteToBitsBE(in[6U], m_rawData + 48U);
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byteToBitsBE(in[7U], m_rawData + 56U);
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byteToBitsBE(in[8U], m_rawData + 64U);
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byteToBitsBE(in[9U], m_rawData + 72U);
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byteToBitsBE(in[10U], m_rawData + 80U);
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byteToBitsBE(in[11U], m_rawData + 88U);
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byteToBitsBE(in[12U], m_rawData + 96U);
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// Handle the two bits
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bool bits[8U];
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byteToBitsBE(in[20U], bits);
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m_rawData[98U] = bits[6U];
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m_rawData[99U] = bits[7U];
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// Second block
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byteToBitsBE(in[21U], m_rawData + 100U);
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byteToBitsBE(in[22U], m_rawData + 108U);
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byteToBitsBE(in[23U], m_rawData + 116U);
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byteToBitsBE(in[24U], m_rawData + 124U);
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byteToBitsBE(in[25U], m_rawData + 132U);
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byteToBitsBE(in[26U], m_rawData + 140U);
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byteToBitsBE(in[27U], m_rawData + 148U);
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byteToBitsBE(in[28U], m_rawData + 156U);
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byteToBitsBE(in[29U], m_rawData + 164U);
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byteToBitsBE(in[30U], m_rawData + 172U);
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byteToBitsBE(in[31U], m_rawData + 180U);
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byteToBitsBE(in[32U], m_rawData + 188U);
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}
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// Deinterleave the raw data
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void CBPTC19696::decodeDeInterleave()
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{
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for (uint32_t i = 0U; i < 196U; i++)
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m_deInterData[i] = false;
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// The first bit is R(3) which is not used so can be ignored
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for (uint32_t a = 0U; a < 196U; a++) {
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// Calculate the interleave sequence
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uint32_t interleaveSequence = (a * 181U) % 196U;
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// Shuffle the data
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m_deInterData[a] = m_rawData[interleaveSequence];
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}
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}
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// Check each row with a Hamming (15,11,3) code and each column with a Hamming (13,9,3) code
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void CBPTC19696::decodeErrorCheck()
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{
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bool fixing;
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uint32_t count = 0U;
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do {
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fixing = false;
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// Run through each of the 15 columns
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bool col[13U];
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for (uint32_t c = 0U; c < 15U; c++) {
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uint32_t pos = c + 1U;
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for (uint32_t a = 0U; a < 13U; a++) {
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col[a] = m_deInterData[pos];
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pos = pos + 15U;
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}
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if (CHamming::decode1393(col)) {
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uint32_t pos = c + 1U;
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for (uint32_t a = 0U; a < 13U; a++) {
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m_deInterData[pos] = col[a];
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pos = pos + 15U;
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}
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fixing = true;
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}
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}
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// Run through each of the 9 rows containing data
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for (uint32_t r = 0U; r < 9U; r++) {
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uint32_t pos = (r * 15U) + 1U;
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if (CHamming::decode15113_2(m_deInterData + pos))
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fixing = true;
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}
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count++;
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} while (fixing && count < 5U);
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}
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// Extract the 96 bits of payload
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void CBPTC19696::decodeExtractData(uint8_t* data)
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{
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bool bData[96U];
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uint32_t pos = 0U;
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for(uint32_t a = 4U; a <= 11U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 16U; a <= 26U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 31U; a <= 41U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 46U; a <= 56U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 61U; a <= 71U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 76U; a <= 86U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 91U; a <= 101U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 106U; a <= 116U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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for(uint32_t a = 121U; a <= 131U; a++, pos++){
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bData[pos] = m_deInterData[a];
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}
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bitsToByteBE(bData + 0U, data[0U]);
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bitsToByteBE(bData + 8U, data[1U]);
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bitsToByteBE(bData + 16U, data[2U]);
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bitsToByteBE(bData + 24U, data[3U]);
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bitsToByteBE(bData + 32U, data[4U]);
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bitsToByteBE(bData + 40U, data[5U]);
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bitsToByteBE(bData + 48U, data[6U]);
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bitsToByteBE(bData + 56U, data[7U]);
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bitsToByteBE(bData + 64U, data[8U]);
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bitsToByteBE(bData + 72U, data[9U]);
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bitsToByteBE(bData + 80U, data[10U]);
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bitsToByteBE(bData + 88U, data[11U]);
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}
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// Extract the 96 bits of payload
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void CBPTC19696::encodeExtractData(const uint8_t* in)
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{
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bool bData[96U];
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byteToBitsBE(in[0U], bData + 0U);
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byteToBitsBE(in[1U], bData + 8U);
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byteToBitsBE(in[2U], bData + 16U);
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byteToBitsBE(in[3U], bData + 24U);
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byteToBitsBE(in[4U], bData + 32U);
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byteToBitsBE(in[5U], bData + 40U);
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byteToBitsBE(in[6U], bData + 48U);
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byteToBitsBE(in[7U], bData + 56U);
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byteToBitsBE(in[8U], bData + 64U);
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byteToBitsBE(in[9U], bData + 72U);
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byteToBitsBE(in[10U], bData + 80U);
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byteToBitsBE(in[11U], bData + 88U);
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for (uint32_t i = 0U; i < 196U; i++)
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m_deInterData[i] = false;
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uint32_t pos = 0U;
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for (uint32_t a = 4U; a <= 11U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 16U; a <= 26U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 31U; a <= 41U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 46U; a <= 56U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 61U; a <= 71U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 76U; a <= 86U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 91U; a <= 101U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 106U; a <= 116U; a++, pos++)
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m_deInterData[a] = bData[pos];
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for (uint32_t a = 121U; a <= 131U; a++, pos++)
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m_deInterData[a] = bData[pos];
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}
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// Check each row with a Hamming (15,11,3) code and each column with a Hamming (13,9,3) code
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void CBPTC19696::encodeErrorCheck()
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{
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// Run through each of the 9 rows containing data
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for (uint32_t r = 0U; r < 9U; r++) {
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uint32_t pos = (r * 15U) + 1U;
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CHamming::encode15113_2(m_deInterData + pos);
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}
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// Run through each of the 15 columns
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bool col[13U];
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for (uint32_t c = 0U; c < 15U; c++) {
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uint32_t pos = c + 1U;
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for (uint32_t a = 0U; a < 13U; a++) {
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col[a] = m_deInterData[pos];
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pos = pos + 15U;
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}
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CHamming::encode1393(col);
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pos = c + 1U;
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for (uint32_t a = 0U; a < 13U; a++) {
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m_deInterData[pos] = col[a];
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pos = pos + 15U;
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}
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}
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}
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// Interleave the raw data
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void CBPTC19696::encodeInterleave()
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{
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for (uint32_t i = 0U; i < 196U; i++)
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m_rawData[i] = false;
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// The first bit is R(3) which is not used so can be ignored
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for (uint32_t a = 0U; a < 196U; a++) {
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// Calculate the interleave sequence
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uint32_t interleaveSequence = (a * 181U) % 196U;
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// Unshuffle the data
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m_rawData[interleaveSequence] = m_deInterData[a];
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}
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}
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void CBPTC19696::encodeExtractBinary(uint8_t* data)
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{
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// First block
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bitsToByteBE(m_rawData + 0U, data[0U]);
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bitsToByteBE(m_rawData + 8U, data[1U]);
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bitsToByteBE(m_rawData + 16U, data[2U]);
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bitsToByteBE(m_rawData + 24U, data[3U]);
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bitsToByteBE(m_rawData + 32U, data[4U]);
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bitsToByteBE(m_rawData + 40U, data[5U]);
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bitsToByteBE(m_rawData + 48U, data[6U]);
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bitsToByteBE(m_rawData + 56U, data[7U]);
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bitsToByteBE(m_rawData + 64U, data[8U]);
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bitsToByteBE(m_rawData + 72U, data[9U]);
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bitsToByteBE(m_rawData + 80U, data[10U]);
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bitsToByteBE(m_rawData + 88U, data[11U]);
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// Handle the two bits
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uint8_t byte;
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bitsToByteBE(m_rawData + 96U, byte);
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data[12U] = (data[12U] & 0x3FU) | ((byte >> 0) & 0xC0U);
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data[20U] = (data[20U] & 0xFCU) | ((byte >> 4) & 0x03U);
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// Second block
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bitsToByteBE(m_rawData + 100U, data[21U]);
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bitsToByteBE(m_rawData + 108U, data[22U]);
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bitsToByteBE(m_rawData + 116U, data[23U]);
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bitsToByteBE(m_rawData + 124U, data[24U]);
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bitsToByteBE(m_rawData + 132U, data[25U]);
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bitsToByteBE(m_rawData + 140U, data[26U]);
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bitsToByteBE(m_rawData + 148U, data[27U]);
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bitsToByteBE(m_rawData + 156U, data[28U]);
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bitsToByteBE(m_rawData + 164U, data[29U]);
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bitsToByteBE(m_rawData + 172U, data[30U]);
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bitsToByteBE(m_rawData + 180U, data[31U]);
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bitsToByteBE(m_rawData + 188U, data[32U]);
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}
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