Add NfcC7_DLL project with initial implementation and solution integration

2025-09-29 09:58:09 +02:00
parent a75d66e028
commit 6571de7c32
5 changed files with 228 additions and 0 deletions
@@ -0,0 +1,160 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+//*****************************************************************************
+// Copyright 2020 Sensus GmbH Ludwigshafen. All rights reserved.
+// Author: Venkat, Rajeshwar
+//*****************************************************************************
+
+namespace Sensus.Poseidon.NfcHandler
+{
+	public static class Tools
+	{
+		public static bool ByteArrayCompare(byte[] a1, byte[] a2)
+		{
+			// thanks to https://stackoverflow.com/questions/43289/comparing-two-byte-arrays-in-net
+			if (a1.Length != a2.Length)
+				return false;
+
+			for (int i = 0; i < a1.Length; i++)
+				if (a1[i] != a2[i])
+					return false;
+
+			return true;
+		}
+		public static string SwapHex(string sHex)
+		{
+			string sResult = "";
+			int iPos = sHex.Length - 2;
+			while (iPos >= 0)
+			{
+				sResult += sHex.Substring(iPos, 2);
+				sHex = sHex.Remove(iPos, 2);
+				iPos = sHex.Length - 2;
+			}
+			return sResult;
+		}
+        public static string DecimalToHexString(string value, int size = 1)
+        {
+            try
+            {
+                long Lval = long.Parse(value);
+                if (size == 1) return Lval.ToString("X2");
+                if (size == 2) return Lval.ToString("X4");
+                if (size == 4) return Lval.ToString("X8");
+            }
+            catch (Exception)
+            {
+                if (size == 1) return "00";
+                if (size == 2) return "0000";
+                if (size == 4) return "00000000";
+            }
+            return "00";
+        }
+        public static string ByteToHexString(byte data)
+        {
+            List<byte> val = new List<byte>();
+            val.Add(data);
+            byte[] arr = val.ToArray();
+            return BytesToHex(arr); 
+        }
+        public static string BytesToHex(byte[] data)
+		{
+			StringBuilder sb = new StringBuilder();
+			foreach (byte b in data)
+				sb.Append(b.ToString("X2"));
+
+			return sb.ToString();
+
+		}
+		public static byte[] HexStringToByteArray(String hexString)
+		{
+			int numberChars = hexString.Length;
+			byte[] bytes = new byte[numberChars / 2];
+			for (int i = 0; i < numberChars; i += 2)
+			{
+				bytes[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
+			}
+			return bytes;
+		}
+        public enum InitialCrcValue
+		{
+			Zeros,
+			NonZero1 = 0xffff,
+			NonZero2 = 0x1D0F
+		}
+
+        public class Crc16Ccitt
+		{
+            private const ushort poly = 0x1021;
+			ushort[] table = new ushort[256];
+			ushort initialValue = 0;
+
+            public ushort ComputeChecksum(byte[] bytes)
+            {
+                ushort crc = this.initialValue;
+                for (int i = 0; i < bytes.Length; ++i)
+                {
+                    crc = (ushort)((crc << 8) ^ table[((crc >> 8) ^ (0xff & bytes[i]))]);
+                }
+                return crc;
+            }
+            public byte[] ComputeChecksumBytes(byte[] bytes)
+            {
+                ushort crc = ComputeChecksum(bytes);
+                return BitConverter.GetBytes(crc);
+            }
+            public Crc16Ccitt(InitialCrcValue initialValue)
+			{
+				this.initialValue = (ushort) initialValue;
+				ushort temp, a;
+				for (int i = 0; i < table.Length; ++i)
+				{
+					temp = 0;
+					a = (ushort) (i << 8);
+					for (int j = 0; j < 8; ++j)
+					{
+						if (((temp ^ a) & 0x8000) != 0)
+						{
+							temp = (ushort) ((temp << 1) ^ poly);
+						}
+						else
+						{
+							temp <<= 1;
+						}
+						a <<= 1;
+					}
+					table[i] = temp;
+				}
+			}
+			public byte[] calcCRCfromMessage(byte[] message)
+			{
+				// CRC calculation goes from MessageID to Password
+				// For Read this means MsgID (1) + Offset (2) + PayloadLength (1) + Password (2) = 6
+				// for write the length of the payload comes on top.
+				// STX(1), length(1), CRC(2) and ETX(1) are excluded, in total 5 bytes.
+				//
+				// the method works both for sending messages (where the CRC and ETX are not in message)
+				// and for receiving messages (where the CRC and ETX are included at the end)
+				byte[] crc_msg = new byte[message[1]];  // message length is 2nd byte
+				Array.Copy(message, 2, crc_msg, 0, crc_msg.Length);
+				return ComputeChecksumBytes(crc_msg);
+			}
+			public string commentCRC(byte[] crc_meter, byte[] crc_computed)
+            {
+				bool crc_do_match = Tools.ByteArrayCompare(crc_meter, crc_computed);
+				string crcComment = crc_do_match ? "ok." : "CRC DOESN'T MATCH!!";
+				return "CRC Meter: " + Tools.BytesToHex(crc_meter) + (crc_do_match ? " == " : " != ")
+					+ "CRC Computed: " + Tools.BytesToHex(crc_computed) + ". " + crcComment;
+			}
+			public bool crc_do_match(byte[] a, byte[] b)
+            {
+				return ByteArrayCompare(a, b);
+			}
+
+		}
+	}
+}