Microsoft.Scripting.Math.BigInteger.IFormattable C# (CSharp) Method

    string IFormattable.ToString(string format, IFormatProvider formatProvider) {
      if (format == null) return this.ToString();

      switch (format[0]) {
        case 'd':
        case 'D':
          if (format.Length > 1) {
            int precision = Convert.ToInt32(format.Substring(1), CultureInfo.InvariantCulture.NumberFormat);
            string baseStr = ToString(10);
            if (baseStr.Length < precision) {
              string additional = new String('0', precision - baseStr.Length);
              if (baseStr[0] != '-') {
                return additional + baseStr;
              } else {
                return "-" + additional + baseStr.Substring(1);
              }
            }
            return baseStr;
          }
          return ToString(10);
        case 'x':
        case 'X':
          StringBuilder res = new StringBuilder(ToString(16));
          if (format[0] == 'x') {
            for (int i = 0; i < res.Length; i++) {
              if (res[i] >= 'A' && res[i] <= 'F') {
                res[i] = Char.ToLower(res[i], CultureInfo.InvariantCulture);
              }
            }
          }

          if (format.Length > 1) {
            int precision = Convert.ToInt32(format.Substring(1), CultureInfo.InvariantCulture.NumberFormat);
            if (res.Length < precision) {
              string additional = new String('0', precision - res.Length);
              if (res[0] != '-') {
                res.Insert(0, additional);
              } else {
                res.Insert(1, additional);
              }
            }
          }

          return res.ToString();
        default:
          throw new NotImplementedException(MathResources.FormatNotImplemented);
      }
    }