MMDVMHost-Private/NXDNLICH.cpp

143 lines
3.4 KiB
C++

/*
* Copyright (C) 2018 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 "NXDNDefines.h"
#include "NXDNLICH.h"
#include "Log.h"
#include <cstdio>
#include <cassert>
#include <cstring>
const unsigned char BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
#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])
#define READ_BIT1(p,i) (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
CNXDNLICH::CNXDNLICH(const CNXDNLICH& lich) :
m_lich(NULL)
{
m_lich = new unsigned char[1U];
m_lich[0U] = lich.m_lich[0U];
}
CNXDNLICH::CNXDNLICH() :
m_lich(NULL)
{
m_lich = new unsigned char[1U];
}
CNXDNLICH::~CNXDNLICH()
{
delete[] m_lich;
}
bool CNXDNLICH::decode(const unsigned char* bytes)
{
assert(bytes != NULL);
bool b[8U];
unsigned int offset1 = NXDN_FSW_LENGTH_BITS;
unsigned int offset2 = 7U;
for (unsigned int i = 0U; i < (NXDN_LICH_LENGTH_BITS / 2U); i++, offset1 += 2U, offset2--) {
b[offset2] = READ_BIT1(bytes, offset1);
WRITE_BIT1(m_lich, i, b[offset2]);
}
bool parity = b[7U] ^ b[6U] ^ b[5U] ^ b[4U];
// LogMessage("NXDN, LICH bits: %d%d %d%d %d%d %d - %d, parity: %d", b[7U] ? 1 : 0, b[6U] ? 1 : 0, b[5U] ? 1 : 0, b[4U] ? 1 : 0, b[3U] ? 1 : 0, b[2U] ? 1 : 0, b[1U] ? 1 : 0, b[0U] ? 1 : 0, parity ? 1 : 0);
if (parity != b[0U])
return false;
return true;
}
void CNXDNLICH::encode(unsigned char* bytes)
{
assert(bytes != NULL);
bool b[8U];
unsigned int offset = 7U;
for (unsigned int i = 0U; i < (NXDN_LICH_LENGTH_BITS / 2U); i++, offset--)
b[offset] = READ_BIT1(m_lich, offset);
b[0U] = b[7U] ^ b[6U] ^ b[5U] ^ b[4U];
unsigned int offset1 = NXDN_FSW_LENGTH_BITS;
unsigned int offset2 = 7U;
for (unsigned int i = 0U; i < (NXDN_LICH_LENGTH_BITS / 2U); i++, offset2--) {
WRITE_BIT1(bytes, offset1, b[offset2]);
offset1++;
WRITE_BIT1(bytes, offset1, true);
offset1++;
}
}
unsigned char CNXDNLICH::getRFCT() const
{
return (m_lich[0U] >> 6) & 0x03U;
}
unsigned char CNXDNLICH::getFCT() const
{
return (m_lich[0U] >> 4) & 0x03U;
}
unsigned char CNXDNLICH::getOption() const
{
return (m_lich[0U] >> 2) & 0x03U;
}
unsigned char CNXDNLICH::getDirection() const
{
return (m_lich[0U] >> 1) & 0x01U;
}
void CNXDNLICH::setRFCT(unsigned char rfct)
{
m_lich[0U] &= 0x3FU;
m_lich[0U] |= (rfct << 6) & 0xC0U;
}
void CNXDNLICH::setFCT(unsigned char usc)
{
m_lich[0U] &= 0xCFU;
m_lich[0U] |= (usc << 4) & 0x30U;
}
void CNXDNLICH::setOption(unsigned char option)
{
m_lich[0U] &= 0xF3U;
m_lich[0u] |= (option << 2) & 0x0CU;
}
void CNXDNLICH::setDirection(unsigned char direction)
{
m_lich[0U] &= 0xFDU;
m_lich[0U] |= (direction << 1) & 0x02U;
}
CNXDNLICH& CNXDNLICH::operator=(const CNXDNLICH& lich)
{
if (&lich != this)
m_lich[0U] = lich.m_lich[0U];
return *this;
}