如何判断 NMEA 或 TAIP 句子是否有效

本文关键字：TAIP 句子 是否 有效 NMEA 何判断 判断 | 更新日期: 2023-09-27 18:30:53

这个问题（我打算自己回答，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...... 本质上是计算校验和应该是什么，并将其与给定的校验和进行比较，并返回真或假......

如何判断 NMEA 或 TAIP 句子是否有效

这是我想出的代码...一些功劳归功于 Carson63000 提供的答案

这里 
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;
    }
}
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