使用 C# 将字符串转换为 GSM 7 位

Question

如何将字符串转换为正确的 GSM 编码值以发送给移动运营商？

Answer 1

下面是gnibbler's answer的端口，稍作修改并附有详细解释。

例子：

string output = GSMConverter.StringToGSMHexString("Hello World");
// output = "48-65-6C-6C-6F-20-57-6F-72-6C-64"

实施：

// Data/info taken from http://en.wikipedia.org/wiki/GSM_03.38
public static class GSMConverter
{
    // The index of the character in the string represents the index
    // of the character in the respective character set

    // Basic Character Set
    private const string BASIC_SET = 
            "@£$¥èéùìòÇ\nØø\rÅåΔ_ΦΓΛΩΠΨΣΘΞ\x1bÆæßÉ !\"#¤%&'()*+,-./0123456789:;<=>?" +
            "¡ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÑܧ¿abcdefghijklmnopqrstuvwxyzäöñüà";

    // Basic Character Set Extension 
    private const string EXTENSION_SET =
            "````````````````````^```````````````````{}`````\\````````````[~]`" +
            "|````````````````````````````````````€``````````````````````````";

    // If the character is in the extension set, it must be preceded
    // with an 'ESC' character whose index is '27' in the Basic Character Set
    private const int ESC_INDEX = 27;

    public static string StringToGSMHexString(string text, bool delimitWithDash = true)
    {
        // Replace \r\n with \r to reduce character count
        text = text.Replace(Environment.NewLine, "\r");

        // Use this list to store the index of the character in 
        // the basic/extension character sets
        var indicies = new List<int>();

        foreach (var c in text)
        {
            int index = BASIC_SET.IndexOf(c);
            if(index != -1) {
                indicies.Add(index);
                continue;
            }

            index = EXTENSION_SET.IndexOf(c);
            if(index != -1) {
                // Add the 'ESC' character index before adding 
                // the extension character index
                indicies.Add(ESC_INDEX);
                indicies.Add(index);
                continue;
            }
        }

      // Convert indicies to 2-digit hex
      var hex = indicies.Select(i => i.ToString("X2")).ToArray();

      string delimiter = delimitWithDash ? "-" : "";

      // Delimit output
      string delimited = string.Join(delimiter, hex);
      return delimited;
    }
}

Answer 2

Omar 的代码对我不起作用。但我发现了有效的实际代码：

public static string Encode7bit(string s)
        {
            string empty = string.Empty;
            for (int index = s.Length - 1; index >= 0; --index)
                empty += Convert.ToString((byte)s[index], 2).PadLeft(8, '0').Substring(1);
            string str1 = empty.PadLeft((int)Math.Ceiling((Decimal)empty.Length / new Decimal(8)) * 8, '0');
            List<byte> byteList = new List<byte>();
            while (str1 != string.Empty)
            {
                string str2 = str1.Substring(0, str1.Length > 7 ? 8 : str1.Length).PadRight(8, '0');
                str1 = str1.Length > 7 ? str1.Substring(8) : string.Empty;
                byteList.Add(Convert.ToByte(str2, 2));
            }
            byteList.Reverse();
            var messageBytes = byteList.ToArray();
            var encodedData = "";
            foreach (byte b in messageBytes)
            {
                encodedData += Convert.ToString(b, 16).PadLeft(2, '0'); 
            }
            return encodedData.ToUpper();
        }