System.util.zlib.ZStream.deflate C# (CSharp) Method

        public int deflate(int flush){
            if(dstate==null){
                return Z_STREAM_ERROR;
            }
            return dstate.deflate(this, flush);
        }
        public int deflateEnd(){

        public override int Read(byte[] b, int off, int len)
        {
            if (len == 0)
            {
                return(0);
            }

            z.next_out       = b;
            z.next_out_index = off;
            z.avail_out      = len;

            int err;

            do
            {
                if (z.avail_in == 0 && !nomoreinput)
                {
                    // if buffer is empty and more input is available, refill it
                    z.next_in_index = 0;
                    z.avail_in      = input.Read(buf, 0, buf.Length);                //(bufsize<z.avail_out ? bufsize : z.avail_out));

                    if (z.avail_in <= 0)
                    {
                        z.avail_in  = 0;
                        nomoreinput = true;
                    }
                }

                err = compress
                                        ?       z.deflate(flushLevel)
                                        :       z.inflate(flushLevel);

                if (nomoreinput && err == JZlib.Z_BUF_ERROR)
                {
                    return(0);
                }
                if (err != JZlib.Z_OK && err != JZlib.Z_STREAM_END)
                {
                    // TODO
//					throw new ZStreamException((compress ? "de" : "in") + "flating: " + z.msg);
                    throw new IOException((compress ? "de" : "in") + "flating: " + z.msg);
                }
                if ((nomoreinput || err == JZlib.Z_STREAM_END) && z.avail_out == len)
                {
                    return(0);
                }
            }while(z.avail_out == len && err == JZlib.Z_OK);
            //Console.Error.WriteLine("("+(len-z.avail_out)+")");
            return(len - z.avail_out);
        }