From b560594caca9e2fa392b37121bda1572c928b67e Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Tue, 19 Apr 2016 06:50:51 +0100
Subject: [PATCH] Add new Hamming for YSF.

---
 BPTC19696.cpp |  4 ++--
 Hamming.cpp   | 58 +++++++++++++++++++++++++++++++++++++++++++++++++--
 Hamming.h     |  9 +++++---
 3 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/BPTC19696.cpp b/BPTC19696.cpp
index 01df707..289005a 100644
--- a/BPTC19696.cpp
+++ b/BPTC19696.cpp
@@ -162,7 +162,7 @@ void CBPTC19696::decodeErrorCheck()
 		// Run through each of the 9 rows containing data
 		for (unsigned int r = 0U; r < 9U; r++) {
 			unsigned int pos = (r * 15U) + 1U;
-			if (CHamming::decode15113(m_deInterData + pos))
+			if (CHamming::decode15113_2(m_deInterData + pos))
 				fixing = true;
 		}
 
@@ -272,7 +272,7 @@ void CBPTC19696::encodeErrorCheck()
 	// Run through each of the 9 rows containing data
 	for (unsigned int r = 0U; r < 9U; r++) {
 		unsigned int pos = (r * 15U) + 1U;
-		CHamming::encode15113(m_deInterData + pos);
+		CHamming::encode15113_2(m_deInterData + pos);
 	}
 	
 	// Run through each of the 15 columns
diff --git a/Hamming.cpp b/Hamming.cpp
index 6652197..fd02392 100644
--- a/Hamming.cpp
+++ b/Hamming.cpp
@@ -21,8 +21,62 @@
 #include <cstdio>
 #include <cassert>
 
+ // Hamming (15,11,3) check a boolean data array
+bool CHamming::decode15113_1(bool* d)
+{
+	assert(d != NULL);
+
+	// Calculate the parity it should have
+	bool c0 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[6];
+	bool c1 = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[7] ^ d[8] ^ d[9];
+	bool c2 = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[8] ^ d[10];
+	bool c3 = d[0] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[9] ^ d[10];
+
+	unsigned char n = 0U;
+	n |= (c0 != d[11]) ? 0x01U : 0x00U;
+	n |= (c1 != d[12]) ? 0x02U : 0x00U;
+	n |= (c2 != d[13]) ? 0x04U : 0x00U;
+	n |= (c3 != d[14]) ? 0x08U : 0x00U;
+
+	switch (n)
+	{
+		// Parity bit errors
+		case 0x01U: d[11] = !d[11]; return true;
+		case 0x02U: d[12] = !d[12]; return true;
+		case 0x04U: d[13] = !d[13]; return true;
+		case 0x08U: d[14] = !d[14]; return true;
+
+		// Data bit errors
+		case 0x0FU: d[0]  = !d[0];  return true;
+		case 0x07U: d[1]  = !d[1];  return true;
+		case 0x0BU: d[2]  = !d[2];  return true;
+		case 0x03U: d[3]  = !d[3];  return true;
+		case 0x0DU: d[4]  = !d[4];  return true;
+		case 0x05U: d[5]  = !d[5];  return true;
+		case 0x09U: d[6]  = !d[6];  return true;
+		case 0x0EU: d[7]  = !d[7];  return true;
+		case 0x06U: d[8]  = !d[8];  return true;
+		case 0x0AU: d[9]  = !d[9];  return true;
+		case 0x0CU: d[10] = !d[10]; return true;
+
+		// No bit errors
+		default: return false;
+	}
+}
+
+void CHamming::encode15113_1(bool* d)
+{
+	assert(d != NULL);
+
+	// Calculate the checksum this row should have
+	d[11] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[4] ^ d[5] ^ d[6];
+	d[12] = d[0] ^ d[1] ^ d[2] ^ d[3] ^ d[7] ^ d[8] ^ d[9];
+	d[13] = d[0] ^ d[1] ^ d[4] ^ d[5] ^ d[7] ^ d[8] ^ d[10];
+	d[14] = d[0] ^ d[2] ^ d[4] ^ d[6] ^ d[7] ^ d[9] ^ d[10];
+}
+
 // Hamming (15,11,3) check a boolean data array
-bool CHamming::decode15113(bool* d)
+bool CHamming::decode15113_2(bool* d)
 {
 	assert(d != NULL);
 
@@ -63,7 +117,7 @@ bool CHamming::decode15113(bool* d)
 	}
 }
 
-void CHamming::encode15113(bool* d)
+void CHamming::encode15113_2(bool* d)
 {
 	assert(d != NULL);
 
diff --git a/Hamming.h b/Hamming.h
index db0cad5..ce9b90b 100644
--- a/Hamming.h
+++ b/Hamming.h
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015,2016 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
@@ -21,8 +21,11 @@
 
 class CHamming {
 public:
-	static void encode15113(bool* d);
-	static bool decode15113(bool* d);
+	static void encode15113_1(bool* d);
+	static bool decode15113_1(bool* d);
+
+	static void encode15113_2(bool* d);
+	static bool decode15113_2(bool* d);
 
 	static void encode1393(bool* d);
 	static bool decode1393(bool* d);