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Revert "Rework the LICH parity."
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This reverts commit 5a22b3d.
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g4klx committed Mar 20, 2018
1 parent 5a22b3d commit 5b45767
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Showing 3 changed files with 20 additions and 46 deletions.
30 changes: 0 additions & 30 deletions NXDNCRC.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -133,25 +133,6 @@ void CNXDNCRC::encodeCRC15(unsigned char* in, unsigned int length)
}
}

bool CNXDNCRC::checkLICHParity(unsigned char in)
{
bool newParity = createLICHParity(in);

bool oldParity = (in & 0x01U) == 0x01U;

return newParity == oldParity;
}

void CNXDNCRC::encodeLICHParity(unsigned char& in)
{
bool parity = createLICHParity(in);

if (parity)
in |= 0x01U;
else
in &= 0xFEU;
}

uint8_t CNXDNCRC::createCRC6(const unsigned char* in, unsigned int length)
{
uint8_t crc = 0x3FU;
Expand Down Expand Up @@ -202,14 +183,3 @@ uint16_t CNXDNCRC::createCRC15(const unsigned char* in, unsigned int length)

return crc & 0x7FFFU;
}

bool CNXDNCRC::createLICHParity(unsigned char in)
{
switch (in & 0xF0U) {
case 0x80U:
case 0xB0U:
return true;
default:
return false;
}
}
4 changes: 0 additions & 4 deletions NXDNCRC.h
Original file line number Diff line number Diff line change
Expand Up @@ -33,14 +33,10 @@ class CNXDNCRC
static bool checkCRC15(const unsigned char* in, unsigned int length);
static void encodeCRC15(unsigned char* in, unsigned int length);

static bool checkLICHParity(unsigned char in);
static void encodeLICHParity(unsigned char& in);

private:
static uint8_t createCRC6(const unsigned char* in, unsigned int length);
static uint16_t createCRC12(const unsigned char* in, unsigned int length);
static uint16_t createCRC15(const unsigned char* in, unsigned int length);
static bool createLICHParity(unsigned char in);
};

#endif
32 changes: 20 additions & 12 deletions NXDNLICH.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,6 @@

#include "NXDNDefines.h"
#include "NXDNLICH.h"
#include "NXDNCRC.h"

#include <cstdio>
#include <cassert>
Expand Down Expand Up @@ -51,26 +50,37 @@ bool CNXDNLICH::decode(const unsigned char* bytes)
{
assert(bytes != NULL);

unsigned int offset = NXDN_FSW_LENGTH_BITS;
for (unsigned int i = 0U; i < (NXDN_LICH_LENGTH_BITS / 2U); i++, offset += 2U) {
bool b = READ_BIT1(bytes, offset);
WRITE_BIT1(m_lich, i, b);
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]);
}

return CNXDNCRC::checkLICHParity(m_lich[0U]);
bool parity = b[7U] ^ b[6U] ^ b[5U] ^ b[4U];

if (parity != b[0U])
return false;

return true;
}

void CNXDNLICH::encode(unsigned char* bytes)
{
assert(bytes != NULL);

CNXDNCRC::encodeLICHParity(m_lich[0U]);
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, i);

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--) {
bool b = READ_BIT1(m_lich, offset2);
WRITE_BIT1(bytes, offset1, b);
WRITE_BIT1(bytes, offset1, b[offset2]);
offset1++;
WRITE_BIT1(bytes, offset1, true);
offset1++;
Expand Down Expand Up @@ -99,8 +109,6 @@ unsigned char CNXDNLICH::getDirection() const

unsigned char CNXDNLICH::getRaw() const
{
CNXDNCRC::encodeLICHParity(m_lich[0U]);

return m_lich[0U];
}

Expand All @@ -119,7 +127,7 @@ void CNXDNLICH::setFCT(unsigned char usc)
void CNXDNLICH::setOption(unsigned char option)
{
m_lich[0U] &= 0xF3U;
m_lich[0U] |= (option << 2) & 0x0CU;
m_lich[0u] |= (option << 2) & 0x0CU;
}

void CNXDNLICH::setDirection(unsigned char direction)
Expand Down

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