c# - 如何判断 NMEA 或 TAIP 句子是否有效

Question

问题（我打算回答自己以自私地提高我的微观声誉）是 C# 代码，用于判断 NMEA 或 TAIP 格式的给定句子是否有效......基本上计算校验和应该是什么并进行比较使用给定的校验和，并返回真或假...

Answer 1

这是我想出的代码...一些功劳归功于 Carson63000在这里提供的答案

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine(IsNMEAMessageValid("$GPRMC,102957.92,A,4104.8569,N,00836.4700,W,0.000,5.822,230211,0,W,A*2B").ToString());
        Console.WriteLine(IsNMEAMessageValid("$GPRMC,102957.92,A,4104.8569,N,00836.4700,W,0.000,5.822,230211,0,W,A*1B").ToString());   // should be false, changed the checksum from 2B to 1B

        Console.WriteLine(IsTAIPMessageValid(">RPV68168+4008572-0828021400026912;ID=M123;*d<").ToString());
        Console.WriteLine(IsTAIPMessageValid(">RPV68168+4008572-0828021400026912;ID=M123;*c<").ToString());    // should be false, changed the checksum from d to c

        Console.WriteLine(IsTAIPMessageValid(">RPV54366+4001403-0828656300005512;ID=GH75;*7c<").ToString());
        Console.WriteLine(IsTAIPMessageValid(">RPV54366+4001403-0828656300005512;ID=GH75;*7b<").ToString());    // should be false, changed the checksum from 7c to 7b

        Console.ReadLine();
    }

    private static bool IsNMEAMessageValid(string sentence)
    {
        // Checksum for NMEA includes XOR on all characters between (not including) the $ and the *, including the commas...
        int checksum = Convert.ToByte(sentence[sentence.IndexOf('$') + 1]);
        for (int i = sentence.IndexOf('$') + 2; i < sentence.IndexOf('*'); i++)
        {
            checksum ^= Convert.ToByte(sentence[i]);
        }
        int givenChecksum = Convert.ToInt16(sentence.Split('*')[1], 16);
        return checksum == givenChecksum;
    }

    private static bool IsTAIPMessageValid(string sentence)
    {
        // Checksum for TAIP includes XOR on all characters starting with > and up to and including *
        int checksum = Convert.ToByte(sentence[sentence.IndexOf('>')]);
        for (int i = sentence.IndexOf('>') + 1; i < sentence.IndexOf('*') + 1; i++)
        {
            checksum ^= Convert.ToByte(sentence[i]);
        }
        char[] splitChars = { '*', '<' };
        int givenChecksum = Convert.ToInt16(sentence.Split(splitChars)[1], 16);
        return checksum == givenChecksum;
    }
}