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Revert "Rework the LICH parity."

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This reverts commit 5a22b3d0a6.
This commit is contained in:
Jonathan Naylor 2018-03-20 20:36:23 +00:00
parent 5a22b3d0a6
commit 5b45767fea
3 changed files with 20 additions and 46 deletions
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30
NXDNCRC.cpp
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@ -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 CNXDNCRC::createCRC6(const unsigned char* in, unsigned int length)
{ {
uint8_t crc = 0x3FU; uint8_t crc = 0x3FU;
@ -202,14 +183,3 @@ uint16_t CNXDNCRC::createCRC15(const unsigned char* in, unsigned int length)
return crc & 0x7FFFU; return crc & 0x7FFFU;
} }
bool CNXDNCRC::createLICHParity(unsigned char in)
{
switch (in & 0xF0U) {
case 0x80U:
case 0xB0U:
return true;
default:
return false;
}
}

4
NXDNCRC.h
View file

@ -33,14 +33,10 @@ public:
static bool checkCRC15(const unsigned char* in, unsigned int length); static bool checkCRC15(const unsigned char* in, unsigned int length);
static void encodeCRC15(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: private:
static uint8_t createCRC6(const unsigned char* in, unsigned int length); 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 createCRC12(const unsigned char* in, unsigned int length);
static uint16_t createCRC15(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 #endif

32
NXDNLICH.cpp
View file

@ -18,7 +18,6 @@
#include "NXDNDefines.h" #include "NXDNDefines.h"
#include "NXDNLICH.h" #include "NXDNLICH.h"
#include "NXDNCRC.h"
#include <cstdio> #include <cstdio>
#include <cassert> #include <cassert>
@ -51,26 +50,37 @@ bool CNXDNLICH::decode(const unsigned char* bytes)
{ {
assert(bytes != NULL); assert(bytes != NULL);
unsigned int offset = NXDN_FSW_LENGTH_BITS; bool b[8U];
for (unsigned int i = 0U; i < (NXDN_LICH_LENGTH_BITS / 2U); i++, offset += 2U) { unsigned int offset1 = NXDN_FSW_LENGTH_BITS;
bool b = READ_BIT1(bytes, offset); unsigned int offset2 = 7U;
WRITE_BIT1(m_lich, i, b); 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) void CNXDNLICH::encode(unsigned char* bytes)
{ {
assert(bytes != NULL); 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 offset1 = NXDN_FSW_LENGTH_BITS;
unsigned int offset2 = 7U; unsigned int offset2 = 7U;
for (unsigned int i = 0U; i < (NXDN_LICH_LENGTH_BITS / 2U); i++, offset2--) { 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[offset2]);
WRITE_BIT1(bytes, offset1, b);
offset1++; offset1++;
WRITE_BIT1(bytes, offset1, true); WRITE_BIT1(bytes, offset1, true);
offset1++; offset1++;
@ -99,8 +109,6 @@ unsigned char CNXDNLICH::getDirection() const
unsigned char CNXDNLICH::getRaw() const unsigned char CNXDNLICH::getRaw() const
{ {
CNXDNCRC::encodeLICHParity(m_lich[0U]);
return m_lich[0U]; return m_lich[0U];
} }
@ -119,7 +127,7 @@ void CNXDNLICH::setFCT(unsigned char usc)
void CNXDNLICH::setOption(unsigned char option) void CNXDNLICH::setOption(unsigned char option)
{ {
m_lich[0U] &= 0xF3U; m_lich[0U] &= 0xF3U;
m_lich[0U] |= (option << 2) & 0x0CU; m_lich[0u] |= (option << 2) & 0x0CU;
} }
void CNXDNLICH::setDirection(unsigned char direction) void CNXDNLICH::setDirection(unsigned char direction)