From 5b45767fea6e331f8404f28dac6007b1597a5043 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Tue, 20 Mar 2018 20:36:23 +0000
Subject: [PATCH] Revert "Rework the LICH parity."

This reverts commit 5a22b3d0a6310201882ffd2b6b00b7ce863a2107.
---
 NXDNCRC.cpp  | 30 ------------------------------
 NXDNCRC.h    |  4 ----
 NXDNLICH.cpp | 32 ++++++++++++++++++++------------
 3 files changed, 20 insertions(+), 46 deletions(-)

diff --git a/NXDNCRC.cpp b/NXDNCRC.cpp
index 861ee7d1c..60278aeef 100644
--- a/NXDNCRC.cpp
+++ b/NXDNCRC.cpp
@@ -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;
@@ -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;
-	}
-}
diff --git a/NXDNCRC.h b/NXDNCRC.h
index 97842a519..12e2e408c 100644
--- a/NXDNCRC.h
+++ b/NXDNCRC.h
@@ -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
diff --git a/NXDNLICH.cpp b/NXDNLICH.cpp
index 40a739217..a61c72bb7 100644
--- a/NXDNLICH.cpp
+++ b/NXDNLICH.cpp
@@ -18,7 +18,6 @@
 
 #include "NXDNDefines.h"
 #include "NXDNLICH.h"
-#include "NXDNCRC.h"
 
 #include <cstdio>
 #include <cassert>
@@ -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++;
@@ -99,8 +109,6 @@ unsigned char CNXDNLICH::getDirection() const
 
 unsigned char CNXDNLICH::getRaw() const
 {
-	CNXDNCRC::encodeLICHParity(m_lich[0U]);
-
 	return m_lich[0U];
 }
 
@@ -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)