Initial commit

owCRC8.cs

@@ -0,0 +1,76 @@
+using System;
+
+namespace OneWireAPI
+{
+	internal class owCRC8
+	{
+		#region Member variables
+
+		private static byte[]		m_aDataTable;		// Lookup table of CRC8 values
+
+		#endregion
+
+		#region Constructor
+
+		static owCRC8()
+		{
+			// Initialize the CRC lookup table
+			InitializeCRCTable();
+		}
+
+		#endregion
+
+		#region Private methods
+
+		private static void InitializeCRCTable()
+		{
+			int		iAccumulator;		// Accumulator value
+			int		iCRC;				// CRC value
+			int		iOuter;				// Outer loop control
+			int		iInner;				// Inner loop control
+
+			// Initialize the size of the lookup table
+			m_aDataTable = new byte[256];
+
+			for (iOuter = 0; iOuter < 256; iOuter++)
+			{
+				iAccumulator = iOuter;
+				iCRC = 0;
+
+				for (iInner = 0; iInner < 8; iInner++)
+				{
+					if (((iAccumulator ^ iCRC) & 0x01) == 0x01)
+						iCRC = ((iCRC ^ 0x18) >> 1) | 0x80;
+					else
+						iCRC = iCRC >> 1;
+
+					iAccumulator = iAccumulator >> 1;
+				}
+
+				m_aDataTable[iOuter] = (byte) iCRC;
+			}
+		}
+
+		#endregion
+
+		#region Public methods
+
+		public static short Calculate(byte[] nData, int iStart, int iEnd)
+		{
+			int		iIndex;						// Loop index
+			short	nCurrentCRC		= 0;		// Current CRC accumulator
+
+			// Loop over all bytes in the input array
+			for (iIndex = iStart; iIndex <= iEnd; iIndex++)
+			{
+				// Calculate the current CRC for this position
+				nCurrentCRC = m_aDataTable[nCurrentCRC ^ nData[iIndex]];
+			}
+
+			// Return the final CRC value
+			return nCurrentCRC;			
+		}
+
+		#endregion
+	}
+}