150 lines
3.8 KiB
C++
150 lines
3.8 KiB
C++
/*
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* Copyright (C) 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 "NXDNCRC.h"
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#include <cstdio>
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#include <cassert>
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const uint8_t BIT_MASK_TABLE1[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
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const uint16_t BIT_MASK_TABLE2[] = { 0x8000U, 0x4000U, 0x2000U, 0x1000U, 0x0800U, 0x0400U, 0x0200U, 0x0100U,
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0x0080U, 0x0040U, 0x0020U, 0x0010U, 0x0008U, 0x0004U, 0x0002U, 0x0001U };
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#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE1[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE1[(i)&7])
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#define READ_BIT1(p,i) (p[(i)>>3] & BIT_MASK_TABLE1[(i)&7])
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#define READ_BIT2(p,i) (p[(i)>>4] & BIT_MASK_TABLE2[(i)&15])
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bool CNXDNCRC::checkCRC6(const unsigned char* in, unsigned int offset, unsigned int length)
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{
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assert(in != NULL);
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uint8_t crc[1U];
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crc[0U] = createCRC6(in, offset, length);
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unsigned int n = offset + length;
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for (unsigned int i = 0U; i < 6U; i++, n++) {
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bool b1 = READ_BIT1(crc, i);
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bool b2 = READ_BIT1(in, n);
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if (b1 != b2)
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return false;
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}
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return true;
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}
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void CNXDNCRC::encodeCRC6(unsigned char* in, unsigned int offset, unsigned int length)
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{
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assert(in != NULL);
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uint8_t crc[1U];
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crc[0U] = createCRC6(in, offset, length);
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unsigned int n = offset + length;
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for (unsigned int i = 0U; i < 6U; i++, n++) {
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bool b = READ_BIT1(crc, i);
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WRITE_BIT1(in, n, b);
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}
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}
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bool CNXDNCRC::checkCRC12(const unsigned char* in, unsigned int offset, unsigned int length)
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{
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assert(in != NULL);
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uint16_t crc[1U];
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crc[0U] = createCRC12(in, offset, length);
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unsigned int n = offset + length;
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for (unsigned int i = 0U; i < 12U; i++, n++) {
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bool b1 = READ_BIT2(crc, i);
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bool b2 = READ_BIT1(in, n);
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if (b1 != b2)
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return false;
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}
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return true;
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}
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void CNXDNCRC::encodeCRC12(unsigned char* in, unsigned int offset, unsigned int length)
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{
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assert(in != NULL);
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uint16_t crc[1U];
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crc[0U] = createCRC12(in, offset, length);
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unsigned int n = offset + length;
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for (unsigned int i = 0U; i < 12U; i++, n++) {
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bool b = READ_BIT2(crc, i);
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WRITE_BIT1(in, n, b);
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}
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}
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bool CNXDNCRC::checkCRC15(const unsigned char* in, unsigned int offset, unsigned int length)
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{
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assert(in != NULL);
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uint16_t crc[1U];
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crc[0U] = createCRC15(in, offset, length);
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unsigned int n = offset + length;
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for (unsigned int i = 0U; i < 15U; i++, n++) {
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bool b1 = READ_BIT2(crc, i);
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bool b2 = READ_BIT1(in, n);
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if (b1 != b2)
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return false;
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}
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return true;
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}
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void CNXDNCRC::encodeCRC15(unsigned char* in, unsigned int offset, unsigned int length)
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{
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assert(in != NULL);
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uint16_t crc[1U];
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crc[0U] = createCRC15(in, offset, length);
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unsigned int n = offset + length;
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for (unsigned int i = 0U; i < 15U; i++, n++) {
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bool b = READ_BIT2(crc, i);
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WRITE_BIT1(in, n, b);
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}
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}
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uint8_t CNXDNCRC::createCRC6(const unsigned char* in, unsigned int offset, unsigned int length)
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{
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uint8_t crc = 0x3FU;
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return crc;
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}
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uint16_t CNXDNCRC::createCRC12(const unsigned char* in, unsigned int offset, unsigned int length)
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{
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uint16_t crc = 0x0FFFU;
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return crc;
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}
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uint16_t CNXDNCRC::createCRC15(const unsigned char* in, unsigned int offset, unsigned int length)
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{
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uint16_t crc = 0x7FFFU;
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return crc;
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}
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