TripleEncodingChars

StringExtensions.cs

public static string TripleEncodeSymbol(this string input, string targetSymbol, string firstSymbol = "$", string secondSymbol = "Z")
{
    if (targetSymbol == firstSymbol)
        throw new ArgumentOutOfRangeException($"{nameof(targetSymbol)} can't be equal {nameof(firstSymbol)}");

    if (targetSymbol == secondSymbol)
        throw new ArgumentOutOfRangeException($"{nameof(targetSymbol)} can't be equal {nameof(secondSymbol)}");

    //return input.Replace("$", "$$$").Replace("Z", "$$Z").Replace(":", "$ZZ");

    return input
        .Replace(firstSymbol, firstSymbol + firstSymbol + firstSymbol)
        .Replace(secondSymbol, firstSymbol + firstSymbol + secondSymbol)
        .Replace(targetSymbol, firstSymbol + secondSymbol + secondSymbol);
}

public static string TripleDecodeSymbol(this string input, string targetSymbol, string firstSymbol = "$", string secondSymbol = "Z")
{
    if (targetSymbol == firstSymbol)
        throw new ArgumentOutOfRangeException($"{nameof(targetSymbol)} can't be equal {nameof(firstSymbol)}");

    if (targetSymbol == secondSymbol)
        throw new ArgumentOutOfRangeException($"{nameof(targetSymbol)} can't be equal {nameof(secondSymbol)}");

    //return input.Replace("$ZZ", ":").Replace("$$Z", "Z").Replace("$$$", "$");

    return input
        .Replace(firstSymbol + secondSymbol + secondSymbol, targetSymbol)
        .Replace(firstSymbol + firstSymbol + secondSymbol, secondSymbol)
        .Replace(firstSymbol + firstSymbol + firstSymbol, firstSymbol);
}