Start on the convolution FEC.
This commit is contained in:
Jonathan Naylor
parent
c549cf3594
commit
5b57557a79
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@ -156,18 +156,8 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
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m_rfLICH.reset();
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CM17Convolution conv;
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conv.start();
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unsigned int n = 2U + M17_SYNC_LENGTH_BYTES;
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for (unsigned int i = 0U; i < (M17_LICH_LENGTH_BYTES / 2U); i++) {
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uint8_t s0 = data[n++];
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uint8_t s1 = data[n++];
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conv.decode(s0, s1);
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}
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unsigned char frame[M17_LICH_LENGTH_BYTES];
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conv.chainback(frame, M17_LICH_LENGTH_BITS);
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conv.decodeLinkSetup(data, frame);
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bool valid = CM17CRC::checkCRC(frame, M17_LICH_LENGTH_BYTES);
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if (valid) {
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@ -224,12 +214,9 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
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unsigned char setup[M17_LICH_LENGTH_BYTES];
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m_rfLICH.getLinkSetup(data + 2U);
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// Add the CRC
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CM17CRC::encodeCRC(data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
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// Add the convolution FEC
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CM17Convolution conv;
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conv.encode(setup, data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.encodeLinkSetup(setup, data + 2U + M17_SYNC_LENGTH_BYTES);
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unsigned char temp[M17_FRAME_LENGTH_BYTES];
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interleaver(data + 2U, temp);
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@ -244,18 +231,8 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
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if (m_rfState == RS_RF_LATE_ENTRY) {
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CM17Convolution conv;
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conv.start();
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unsigned int n = 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES;
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for (unsigned int i = 0U; i < (M17_LICH_LENGTH_BYTES / 2U); i++) {
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uint8_t s0 = data[n++];
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uint8_t s1 = data[n++];
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conv.decode(s0, s1);
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}
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unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
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conv.chainback(frame, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.decodeData(data, frame);
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bool valid = CM17CRC::checkCRC(frame, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
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if (valid) {
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@ -322,12 +299,9 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
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unsigned char setup[M17_LICH_LENGTH_BYTES];
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m_rfLICH.getLinkSetup(data + 2U);
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// Add the CRC
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CM17CRC::encodeCRC(data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
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// Add the convolution FEC
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CM17Convolution conv;
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conv.encode(setup, data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.encodeLinkSetup(setup, data + 2U + M17_SYNC_LENGTH_BYTES);
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unsigned char temp[M17_FRAME_LENGTH_BYTES];
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interleaver(data + 2U, temp);
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@ -344,18 +318,8 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
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writeFile(data + 2U);
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#endif
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CM17Convolution conv;
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conv.start();
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unsigned int n = 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES;
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for (unsigned int i = 0U; i < ((M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES) / 2U); i++) {
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uint8_t s0 = data[n++];
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uint8_t s1 = data[n++];
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conv.decode(s0, s1);
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}
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unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
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conv.chainback(frame, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.decodeData(data, frame);
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bool valid = CM17CRC::checkCRC(frame, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
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if (valid) {
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@ -399,7 +363,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
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// XXX TODO Golay on LICH fragment
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// Re-encode the payload
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conv.encode(frame, rfData + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.encodeData(frame, rfData + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES);
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// Calculate the BER
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if (valid) {
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@ -551,12 +515,9 @@ void CM17Control::writeNetwork()
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unsigned char setup[M17_LICH_LENGTH_BYTES];
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m_netLICH.getLinkSetup(start + 2U);
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// Add the CRC
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CM17CRC::encodeCRC(start + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
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// Add the convolution FEC
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CM17Convolution conv;
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conv.encode(setup, start + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.encodeLinkSetup(setup, start + 2U + M17_SYNC_LENGTH_BYTES);
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unsigned char temp[M17_FRAME_LENGTH_BYTES];
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interleaver(start + 2U, temp);
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@ -616,7 +577,7 @@ void CM17Control::writeNetwork()
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// Add the Convolution FEC
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CM17Convolution conv;
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conv.encode(payload, p, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
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conv.encodeData(payload, p);
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unsigned char temp[M17_FRAME_LENGTH_BYTES];
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interleaver(data + 2U, temp);
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276
M17Convolution.cpp
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276
M17Convolution.cpp
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@ -0,0 +1,276 @@
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/*
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* Copyright (C) 2009-2016,2018 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 "M17Convolution.h"
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#include <cstdio>
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#include <cassert>
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#include <cstring>
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#include <cstdlib>
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const unsigned int PUNCTURE_LIST_LINK_SETUP[] = { 3U, 11U, 17U, 25U, 31U, 39U, 45U, 53U, 59U, 67U,
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73U, 81U, 87U, 95U, 101U, 109U, 115U, 123U, 129U, 137U,
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143U, 151U, 157U, 165U, 171U, 179U, 185U, 193U, 199U, 207U,
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213U, 221U, 227U, 235U, 241U, 249U, 255U, 263U, 269U, 277U,
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283U, 291U, 297U, 305U, 311U, 319U, 325U, 333U, 339U, 347U,
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353U, 361U, 367U, 375U, 381U, 389U, 395U, 403U };
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const unsigned int PUNCTURE_LIST_DATA[] = { 3U, 11U, 17U, 25U, 31U, 39U, 45U, 53U, 59U, 67U,
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73U, 81U, 87U, 95U, 101U, 109U, 115U, 123U, 129U, 137U,
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143U, 151U, 157U, 165U, 171U, 179U, 185U, 193U, 199U, 207U,
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213U, 221U, 227U, 235U, 241U, 249U, 255U, 263U, 269U, 277U,
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283U, 291U, 297U, 305U, 311U, 319U, 325U, 333U, 339U, 347U,
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353U, 361U, 367U, 375U, 381U, 389U, 395U, 403U };
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const unsigned char BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
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#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
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#define READ_BIT1(p,i) (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
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const uint8_t BRANCH_TABLE1[] = {0U, 0U, 0U, 0U, 2U, 2U, 2U, 2U};
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const uint8_t BRANCH_TABLE2[] = {0U, 2U, 2U, 0U, 0U, 2U, 2U, 0U};
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const unsigned int NUM_OF_STATES_D2 = 8U;
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const unsigned int NUM_OF_STATES = 16U;
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const uint32_t M = 4U;
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const unsigned int K = 5U;
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CM17Convolution::CM17Convolution() :
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m_metrics1(NULL),
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m_metrics2(NULL),
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m_oldMetrics(NULL),
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m_newMetrics(NULL),
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m_decisions(NULL),
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m_dp(NULL)
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{
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m_metrics1 = new uint16_t[16U];
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m_metrics2 = new uint16_t[16U];
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m_decisions = new uint64_t[300U];
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}
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CM17Convolution::~CM17Convolution()
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{
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delete[] m_metrics1;
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delete[] m_metrics2;
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delete[] m_decisions;
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}
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void CM17Convolution::encodeLinkSetup(const unsigned char* in, unsigned char* out) const
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{
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assert(in != NULL);
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assert(out != NULL);
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unsigned char temp1[31U];
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::memset(temp1, 0x00U, 31U);
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::memcpy(temp1, in, 30U);
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unsigned char temp2[61U];
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encode(temp1, temp2, 244U);
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unsigned int n = 0U;
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unsigned int index = 0U;
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for (unsigned int i = 0U; i < 488U; i++) {
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if (i != PUNCTURE_LIST_LINK_SETUP[index]) {
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bool b = READ_BIT1(temp2, i);
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WRITE_BIT1(out, n, b);
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n++;
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} else {
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index++;
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}
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}
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}
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void CM17Convolution::encodeData(const unsigned char* in, unsigned char* out) const
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{
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assert(in != NULL);
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assert(out != NULL);
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unsigned char temp1[21U];
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::memset(temp1, 0x00U, 21U);
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::memcpy(temp1, in, 20U);
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unsigned char temp2[41U];
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encode(temp1, temp2, 164U);
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unsigned int n = 0U;
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unsigned int index = 0U;
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for (unsigned int i = 0U; i < 328U; i++) {
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if (i != PUNCTURE_LIST_DATA[index]) {
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bool b = READ_BIT1(temp2, i);
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WRITE_BIT1(out, n, b);
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n++;
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} else {
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index++;
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}
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}
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}
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void CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned char* out)
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{
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assert(in != NULL);
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assert(out != NULL);
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uint8_t temp[488U];
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unsigned int n = 0U;
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unsigned int index = 0U;
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for (unsigned int i = 0U; i < 368U; i++) {
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if (n == PUNCTURE_LIST_LINK_SETUP[index]) {
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temp[n++] = 1U;
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index++;
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}
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bool b = READ_BIT1(in, i);
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temp[n++] = b ? 2U : 0U;
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}
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for (unsigned int i = 0U; i < 8U; i++)
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temp[n++] = 0U;
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start();
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n = 0U;
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for (unsigned int i = 0U; i < 244U; i++) {
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uint8_t s0 = temp[n++];
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uint8_t s1 = temp[n++];
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decode(s0, s1);
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}
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chainback(out, 244U);
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}
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void CM17Convolution::decodeData(const unsigned char* in, unsigned char* out)
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{
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assert(in != NULL);
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assert(out != NULL);
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uint8_t temp[328U];
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unsigned int n = 0U;
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unsigned int index = 0U;
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for (unsigned int i = 0U; i < 272U; i++) {
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if (n == PUNCTURE_LIST_DATA[index]) {
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temp[n++] = 1U;
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index++;
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}
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bool b = READ_BIT1(in, i);
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temp[n++] = b ? 2U : 0U;
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}
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for (unsigned int i = 0U; i < 8U; i++)
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temp[n++] = 0U;
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start();
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n = 0U;
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for (unsigned int i = 0U; i < 164U; i++) {
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uint8_t s0 = temp[n++];
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uint8_t s1 = temp[n++];
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decode(s0, s1);
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}
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chainback(out, 164U);
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}
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void CM17Convolution::start()
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{
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::memset(m_metrics1, 0x00U, NUM_OF_STATES * sizeof(uint16_t));
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::memset(m_metrics2, 0x00U, NUM_OF_STATES * sizeof(uint16_t));
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m_oldMetrics = m_metrics1;
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m_newMetrics = m_metrics2;
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m_dp = m_decisions;
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}
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void CM17Convolution::decode(uint8_t s0, uint8_t s1)
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{
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*m_dp = 0U;
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for (uint8_t i = 0U; i < NUM_OF_STATES_D2; i++) {
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uint8_t j = i * 2U;
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uint16_t metric = std::abs(BRANCH_TABLE1[i] - s0) + std::abs(BRANCH_TABLE2[i] - s1);
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uint16_t m0 = m_oldMetrics[i] + metric;
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uint16_t m1 = m_oldMetrics[i + NUM_OF_STATES_D2] + (M - metric);
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uint8_t decision0 = (m0 >= m1) ? 1U : 0U;
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m_newMetrics[j + 0U] = decision0 != 0U ? m1 : m0;
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m0 = m_oldMetrics[i] + (M - metric);
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m1 = m_oldMetrics[i + NUM_OF_STATES_D2] + metric;
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uint8_t decision1 = (m0 >= m1) ? 1U : 0U;
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m_newMetrics[j + 1U] = decision1 != 0U ? m1 : m0;
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*m_dp |= (uint64_t(decision1) << (j + 1U)) | (uint64_t(decision0) << (j + 0U));
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}
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++m_dp;
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assert((m_dp - m_decisions) <= 300);
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uint16_t* tmp = m_oldMetrics;
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m_oldMetrics = m_newMetrics;
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m_newMetrics = tmp;
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}
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void CM17Convolution::chainback(unsigned char* out, unsigned int nBits)
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{
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assert(out != NULL);
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uint32_t state = 0U;
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while (nBits-- > 0) {
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--m_dp;
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uint32_t i = state >> (9 - K);
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uint8_t bit = uint8_t(*m_dp >> i) & 1;
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state = (bit << 7) | (state >> 1);
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WRITE_BIT1(out, nBits, bit != 0U);
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}
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}
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void CM17Convolution::encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const
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{
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assert(in != NULL);
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assert(out != NULL);
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assert(nBits > 0U);
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uint8_t d1 = 0U, d2 = 0U, d3 = 0U, d4 = 0U;
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uint32_t k = 0U;
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for (unsigned int i = 0U; i < nBits; i++) {
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uint8_t d = READ_BIT1(in, i) ? 1U : 0U;
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uint8_t g1 = (d + d3 + d4) & 1;
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uint8_t g2 = (d + d1 + d2 + d4) & 1;
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d4 = d3;
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d3 = d2;
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d2 = d1;
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d1 = d;
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WRITE_BIT1(out, k, g1 != 0U);
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k++;
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WRITE_BIT1(out, k, g2 != 0U);
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k++;
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}
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}
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@ -26,11 +26,11 @@ public:
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CM17Convolution();
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~CM17Convolution();
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void start();
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void decode(uint8_t s0, uint8_t s1);
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void chainback(unsigned char* out, unsigned int nBits);
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void decodeLinkSetup(const unsigned char* in, unsigned char* out);
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void decodeData(const unsigned char* in, unsigned char* out);
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void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;
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void encodeLinkSetup(const unsigned char* in, unsigned char* out) const;
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void encodeData(const unsigned char* in, unsigned char* out) const;
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private:
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uint16_t* m_metrics1;
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@ -39,6 +39,12 @@ private:
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uint16_t* m_newMetrics;
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uint64_t* m_decisions;
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uint64_t* m_dp;
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void start();
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void decode(uint8_t s0, uint8_t s1);
|
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void chainback(unsigned char* out, unsigned int nBits);
|
||||
|
||||
void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;
|
||||
};
|
||||
|
||||
#endif
|
||||
|
|
|
|||
11
M17LICH.cpp
11
M17LICH.cpp
|
|
@ -22,17 +22,6 @@
|
|||
|
||||
#include <cassert>
|
||||
|
||||
CM17LICH::CM17LICH(const CM17LICH& lich) :
|
||||
m_lich(NULL),
|
||||
m_valid(false)
|
||||
{
|
||||
m_lich = new unsigned char[30U];
|
||||
|
||||
::memcpy(m_lich, lich.m_lich, 30U);
|
||||
|
||||
m_valid = lich.m_valid;
|
||||
}
|
||||
|
||||
CM17LICH::CM17LICH() :
|
||||
m_lich(NULL),
|
||||
m_valid(false)
|
||||
|
|
|
|||
|
|
@ -23,7 +23,6 @@
|
|||
|
||||
class CM17LICH {
|
||||
public:
|
||||
CM17LICH(const CM17LICH& lich);
|
||||
CM17LICH();
|
||||
~CM17LICH();
|
||||
|
||||
|
|
@ -48,8 +47,6 @@ public:
|
|||
void getFragment(unsigned char* data, unsigned short fn) const;
|
||||
void setFragment(const unsigned char* data, unsigned short fn);
|
||||
|
||||
CM17LICH& operator=(const CM17LICH& lich);
|
||||
|
||||
private:
|
||||
unsigned char* m_lich;
|
||||
bool m_valid;
|
||||
|
|
|
|||
|
|
@ -291,6 +291,7 @@
|
|||
<ClCompile Include="LCDproc.cpp" />
|
||||
<ClCompile Include="Log.cpp" />
|
||||
<ClCompile Include="M17Control.cpp" />
|
||||
<ClCompile Include="M17Convolution.cpp" />
|
||||
<ClCompile Include="M17CRC.cpp" />
|
||||
<ClCompile Include="M17LICH.cpp" />
|
||||
<ClCompile Include="M17Network.cpp" />
|
||||
|
|
|
|||
|
|
@ -598,5 +598,8 @@
|
|||
<ClCompile Include="M17LICH.cpp">
|
||||
<Filter>Source Files</Filter>
|
||||
</ClCompile>
|
||||
<ClCompile Include="M17Convolution.cpp">
|
||||
<Filter>Source Files</Filter>
|
||||
</ClCompile>
|
||||
</ItemGroup>
|
||||
</Project>
|
||||
Loading…
Reference in a new issue