From cf2f8ee3c8df8c6eaedf3f7f15d4bef3fbe14210 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Tue, 23 Jan 2018 21:29:25 +0000
Subject: [PATCH] Make the punctured convolution code processed correctly.

---
 NXDNControl.cpp     |  2 ++
 NXDNConvolution.cpp |  6 +++---
 NXDNSACCH.cpp       | 35 ++++++++++++++++++++++-------------
 3 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/NXDNControl.cpp b/NXDNControl.cpp
index 742f34f..f1761e9 100644
--- a/NXDNControl.cpp
+++ b/NXDNControl.cpp
@@ -165,6 +165,8 @@ bool CNXDNControl::processVoice(unsigned char usc, unsigned char option, unsigne
 	CNXDNSACCH sacch;
 	sacch.decode(data + 2U);
 
+	sacch.encode(data + 2U);
+
 #ifdef notdef
 	unsigned char fi = m_lastFICH.getFI();
 	if (valid && fi == YSF_FI_HEADER) {
diff --git a/NXDNConvolution.cpp b/NXDNConvolution.cpp
index 7120d6b..83f73a0 100644
--- a/NXDNConvolution.cpp
+++ b/NXDNConvolution.cpp
@@ -27,12 +27,12 @@ const unsigned char BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U
 #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])
 
-const uint8_t BRANCH_TABLE1[] = {0U, 0U, 0U, 0U, 1U, 1U, 1U, 1U};
-const uint8_t BRANCH_TABLE2[] = {0U, 1U, 1U, 0U, 0U, 1U, 1U, 0U};
+const uint8_t BRANCH_TABLE1[] = {0U, 0U, 0U, 0U, 2U, 2U, 2U, 2U};
+const uint8_t BRANCH_TABLE2[] = {0U, 2U, 2U, 0U, 0U, 2U, 2U, 0U};
 
 const unsigned int NUM_OF_STATES_D2 = 8U;
 const unsigned int NUM_OF_STATES = 16U;
-const uint32_t     M = 2U;
+const uint32_t     M = 4U;
 const unsigned int K = 5U;
 
 CNXDNConvolution::CNXDNConvolution() :
diff --git a/NXDNSACCH.cpp b/NXDNSACCH.cpp
index 073f764..b1e7ea6 100644
--- a/NXDNSACCH.cpp
+++ b/NXDNSACCH.cpp
@@ -22,6 +22,7 @@
 #include "NXDNDefines.h"
 #include "NXDNCRC.h"
 #include "Utils.h"
+#include "Log.h"
 
 #include <cstdio>
 #include <cassert>
@@ -76,41 +77,41 @@ bool CNXDNSACCH::decode(const unsigned char* data)
 
 	CUtils::dump("NXDN, SACCH de-interleaved", temp1, 8U);
 
-	unsigned char temp2[9U];
+	uint8_t temp2[72U];
+
+	char text[500U];
+	::strcpy(text, "NXDN, SACCH de-punctured: ");
 
 	unsigned int n = 0U;
 	unsigned int index = 0U;
 	for (unsigned int i = 0U; i < NXDN_SACCH_LENGTH_BITS; i++) {
-		if (i == PUNCTURE_LIST[index]) {
-			WRITE_BIT1(temp2, n, false);
+		if (n == PUNCTURE_LIST[index]) {
+			::strcat(text, "1, ");
+			temp2[n++] = 1U;
 			index++;
-			n++;
 		}
 
 		bool b = READ_BIT1(temp1, i);
-		WRITE_BIT1(temp2, n, b);
-		n++;
+		temp2[n++] = b ? 2U : 0U;
+		::strcat(text, b ? "2, " : "0, ");
 	}
 
-	CUtils::dump("NXDN, SACCH de-punctured", temp2, 9U);
+	LogMessage(text);
 
 	CNXDNConvolution conv;
 	conv.start();
 
 	n = 0U;
 	for (unsigned int i = 0U; i < 36U; i++) {
-		uint8_t s0 = READ_BIT1(temp2, n) ? 1U : 0U;
-		n++;
-
-		uint8_t s1 = READ_BIT1(temp2, n) ? 1U : 0U;
-		n++;
+		uint8_t s0 = temp2[n++];
+		uint8_t s1 = temp2[n++];
 
 		conv.decode(s0, s1);
 	}
 
 	conv.chainback(m_data, 36U);
 
-	CUtils::dump("NXDN, SACCH", m_data, 5U);
+	CUtils::dump("NXDN, SACCH decoded", m_data, 5U);
 
 	return CNXDNCRC::checkCRC6(m_data, 26U);
 }
@@ -129,11 +130,15 @@ void CNXDNSACCH::encode(unsigned char* data) const
 
 	CNXDNCRC::encodeCRC6(temp1, 26U);
 
+	CUtils::dump("NXDN, SACCH encoded with CRC", temp1, 5U);
+
 	unsigned char temp2[9U];
 
 	CNXDNConvolution conv;
 	conv.encode(temp1, temp2, 36U);
 
+	CUtils::dump("NXDN, SACCH convolved", temp2, 9U);
+
 	unsigned char temp3[8U];
 
 	unsigned int n = 0U;
@@ -148,11 +153,15 @@ void CNXDNSACCH::encode(unsigned char* data) const
 		}
 	}
 
+	CUtils::dump("NXDN, SACCH punctured", temp3, 8U);
+
 	for (unsigned int i = 0U; i < NXDN_SACCH_LENGTH_BITS; i++) {
 		unsigned int n = INTERLEAVE_TABLE[i] + NXDN_FSW_LENGTH_BITS + NXDN_LICH_LENGTH_BITS;
 		bool b = READ_BIT1(temp3, i);
 		WRITE_BIT1(data, n, b);
 	}
+
+	CUtils::dump("NXDN, SACCH re-encoded", data, 12U);
 }
 
 unsigned char CNXDNSACCH::getRAN() const