NCOF: secure possible index overflow by 1 due to float to int conversion

sdrbase/dsp/ncof.cpp

@@ -23,16 +23,19 @@
 #undef M_PI
 #define M_PI		3.14159265358979323846
 
-Real NCOF::m_table[NCOF::TableSize];
+Real NCOF::m_table[NCOF::TableSize+1];
 bool NCOF::m_tableInitialized = false;
+float NCOF::m_tableSizeLimit = (float) NCOF::TableSize;
 
 void NCOF::initTable()
 {
-	if(m_tableInitialized)
+	if(m_tableInitialized) {
 		return;
+	}
 
-	for(int i = 0; i < TableSize; i++)
+	for(int i = 0; i <= TableSize; i++) {
 		m_table[i] = cos((2.0 * M_PI * i) / TableSize);
+	}
 
 	m_tableInitialized = true;
 }

sdrbase/dsp/ncof.h

@@ -25,8 +25,9 @@ private:
 	enum {
 		TableSize = (1 << 12),
 	};
-	static Real m_table[TableSize];
+	static Real m_table[TableSize+1];
 	static bool m_tableInitialized;
+	static float m_tableSizeLimit;
 
 	static void initTable();
 
@@ -42,10 +43,12 @@ public:
 	int nextPhase()        //!< Increment phase and return its integer value
 	{
 		m_phase += m_phaseIncrement;
-		while(m_phase >= TableSize)
+		while(m_phase >= m_tableSizeLimit) {
 			m_phase -= TableSize;
-		while(m_phase < 0)
+		}
+		while(m_phase < 0.0) {
 			m_phase += TableSize;
+		}
 		return (int) m_phase;
 	}