Google.Protobuf.JsonFormatter.ToCamelCase C# (CSharp) Method

        internal static string ToCamelCase(string input)
        {
            bool capitalizeNext = false;
            bool wasCap = true;
            bool isCap = false;
            bool firstWord = true;
            StringBuilder result = new StringBuilder(input.Length);

            for (int i = 0; i < input.Length; i++, wasCap = isCap)
            {
                isCap = char.IsUpper(input[i]);
                if (input[i] == '_')
                {
                    capitalizeNext = true;
                    if (result.Length != 0)
                    {
                        firstWord = false;
                    }
                    continue;
                }
                else if (firstWord)
                {
                    // Consider when the current character B is capitalized,
                    // first word ends when:
                    // 1) following a lowercase:   "...aB..."
                    // 2) followed by a lowercase: "...ABc..."
                    if (result.Length != 0 && isCap &&
                        (!wasCap || (i + 1 < input.Length && char.IsLower(input[i + 1]))))
                    {
                        firstWord = false;
                    }
                    else
                    {
                        result.Append(char.ToLowerInvariant(input[i]));
                        continue;
                    }
                }
                else if (capitalizeNext)
                {
                    capitalizeNext = false;
                    if (char.IsLower(input[i]))
                    {
                        result.Append(char.ToUpperInvariant(input[i]));
                        continue;
                    }
                }
                result.Append(input[i]);
            }
            return result.ToString();
        }
        

 public void ToCamelCase(string original, string expected)
 {
     Assert.AreEqual(expected, JsonFormatter.ToCamelCase(original));
 }