System.Text.EncoderNLS.GetByteCount C# (CSharp) Method

        public unsafe override int GetByteCount(char[] chars, int index, int count, bool flush)
        {
            // Validate input parameters
            if (chars == null)
                throw new ArgumentNullException(nameof(chars), SR.ArgumentNull_Array);

            if (index < 0 || count < 0)
                throw new ArgumentOutOfRangeException((index < 0 ? nameof(index): nameof(count)), SR.ArgumentOutOfRange_NeedNonNegNum);

            if (chars.Length - index < count)
                throw new ArgumentOutOfRangeException(nameof(chars), SR.ArgumentOutOfRange_IndexCountBuffer);
            Contract.EndContractBlock();

            // Avoid empty input problem
            if (chars.Length == 0)
                chars = new char[1];

            // Just call the pointer version
            int result = -1;
            fixed (char* pChars = chars)
            {
                result = GetByteCount(pChars + index, count, flush);
            }
            return result;
        }