//<summary>
        /// Read in a JSON string containing base-64 encoded data and decode it.
        ///</summary>
        private byte[] ReadJSONBase64()
        {
            byte[] b    = ReadJSONString(false);
            int    len  = b.Length;
            int    off  = 0;
            int    size = 0;

            while (len >= 4)
            {
                // Decode 4 bytes at a time
                TBase64Utils.decode(b, off, 4, b, size);                 // NB: decoded in place
                off  += 4;
                len  -= 4;
                size += 3;
            }
            // Don't decode if we hit the end or got a single leftover byte (invalid
            // base64 but legal for skip of regular string type)
            if (len > 1)
            {
                // Decode remainder
                TBase64Utils.decode(b, off, len, b, size);                 // NB: decoded in place
                size += len - 1;
            }
            // Sadly we must copy the byte[] (any way around this?)
            byte[] result = new byte[size];
            Array.Copy(b, 0, result, 0, size);
            return(result);
        }
        ///<summary>
        /// Write out contents of byte array b as a JSON string with base-64 encoded
        /// data
        ///</summary>
        private void WriteJSONBase64(byte[] b)
        {
            context.Write();
            trans.Write(QUOTE);

            int len = b.Length;
            int off = 0;

            while (len >= 3)
            {
                // Encode 3 bytes at a time
                TBase64Utils.encode(b, off, 3, tempBuffer, 0);
                trans.Write(tempBuffer, 0, 4);
                off += 3;
                len -= 3;
            }
            if (len > 0)
            {
                // Encode remainder
                TBase64Utils.encode(b, off, len, tempBuffer, 0);
                trans.Write(tempBuffer, 0, len + 1);
            }

            trans.Write(QUOTE);
        }