Rebex.IO.Compression.ZStream.flush_pending C# (CSharp) Method

        internal void flush_pending()
        {
            int len = dstate.pending;

            if (len > avail_out)
                len = avail_out;
            if (len == 0)
                return ;

            if (dstate.pending_buf.Length <= dstate.pending_out || next_out.Length <= next_out_index || dstate.pending_buf.Length < (dstate.pending_out + len) || next_out.Length < (next_out_index + len))
            {
                //System.Console.Out.WriteLine(dstate.pending_buf.Length + ", " + dstate.pending_out + ", " + next_out.Length + ", " + next_out_index + ", " + len);
                //System.Console.Out.WriteLine("avail_out=" + avail_out);
            }

            Array.Copy(dstate.pending_buf, dstate.pending_out, next_out, next_out_index, len);

            next_out_index += len;
            dstate.pending_out += len;
            total_out += len;
            avail_out -= len;
            dstate.pending -= len;
            if (dstate.pending == 0)
            {
                dstate.pending_out = 0;
            }
        }

        internal int deflate(ZStream strm, int flush)
        {
            int old_flush;

            if (flush > Z_FINISH || flush < 0)
            {
                return Z_STREAM_ERROR;
            }

            if (strm.next_out == null || (strm.next_in == null && strm.avail_in != 0) || (status == FINISH_STATE && flush != Z_FINISH))
            {
                strm.msg = z_errmsg[Z_NEED_DICT - (Z_STREAM_ERROR)];
                return Z_STREAM_ERROR;
            }
            if (strm.avail_out == 0)
            {
                strm.msg = z_errmsg[Z_NEED_DICT - (Z_BUF_ERROR)];
                return Z_BUF_ERROR;
            }

            this.strm = strm; // just in case
            old_flush = last_flush;
            last_flush = flush;

            // Write the zlib header
            if (status == INIT_STATE)
            {
                int header = (Z_DEFLATED + ((w_bits - 8) << 4)) << 8;
                int level_flags = ((level - 1) & 0xff) >> 1;

                if (level_flags > 3)
                    level_flags = 3;
                header |= (level_flags << 6);
                if (strstart != 0)
                    header |= PRESET_DICT;
                header += 31 - (header % 31);

                status = BUSY_STATE;

                //nanook
                //putShortMSB(header);

                // Save the adler32 of the preset dictionary:
                if (strstart != 0)
                {
                    putShortMSB((int) (SupportClass.URShift(strm.adler, 16)));
                    putShortMSB((int) (strm.adler & 0xffff));
                }
                strm.adler = strm._adler.adler32(0, null, 0, 0);
            }

            // Flush as much pending output as possible
            if (pending != 0)
            {
                strm.flush_pending();
                if (strm.avail_out == 0)
                {
                    //System.out.println("  avail_out==0");
                    // Since avail_out is 0, deflate will be called again with
                    // more output space, but possibly with both pending and
                    // avail_in equal to zero. There won't be anything to do,
                    // but this is not an error situation so make sure we
                    // return OK instead of BUF_ERROR at next call of deflate:
                    last_flush = - 1;
                    return Z_OK;
                }

                // Make sure there is something to do and avoid duplicate consecutive
                // flushes. For repeated and useless calls with Z_FINISH, we keep
                // returning Z_STREAM_END instead of Z_BUFF_ERROR.
            }
            else if (strm.avail_in == 0 && flush <= old_flush && flush != Z_FINISH)
            {
                strm.msg = z_errmsg[Z_NEED_DICT - (Z_BUF_ERROR)];
                return Z_BUF_ERROR;
            }

            // User must not provide more input after the first FINISH:
            if (status == FINISH_STATE && strm.avail_in != 0)
            {
                strm.msg = z_errmsg[Z_NEED_DICT - (Z_BUF_ERROR)];
                return Z_BUF_ERROR;
            }

            // Start a new block or continue the current one.
            if (strm.avail_in != 0 || lookahead != 0 || (flush != Z_NO_FLUSH && status != FINISH_STATE))
            {
                int bstate = - 1;
                switch (config_table[level].func)
                {

                    case STORED:
                        bstate = deflate_stored(flush);
                        break;

                    case FAST:
                        bstate = deflate_fast(flush);
                        break;

                    case SLOW:
                        bstate = deflate_slow(flush);
                        break;

                    default:
                        break;

                }

                if (bstate == FinishStarted || bstate == FinishDone)
                {
                    status = FINISH_STATE;
                }
                if (bstate == NeedMore || bstate == FinishStarted)
                {
                    if (strm.avail_out == 0)
                    {
                        last_flush = - 1; // avoid BUF_ERROR next call, see above
                    }
                    return Z_OK;
                    // If flush != Z_NO_FLUSH && avail_out == 0, the next call
                    // of deflate should use the same flush parameter to make sure
                    // that the flush is complete. So we don't have to output an
                    // empty block here, this will be done at next call. This also
                    // ensures that for a very small output buffer, we emit at most
                    // one empty block.
                }

                if (bstate == BlockDone)
                {
                    if (flush == Z_PARTIAL_FLUSH)
                    {
                        _tr_align();
                    }
                    else
                    {
                        // FULL_FLUSH or SYNC_FLUSH
                        _tr_stored_block(0, 0, false);
                        // For a full flush, this empty block will be recognized
                        // as a special marker by inflate_sync().
                        if (flush == Z_FULL_FLUSH)
                        {
                            //state.head[s.hash_size-1]=0;
                            for (int i = 0; i < hash_size; i++)
                            // forget history
                                head[i] = 0;
                        }
                    }
                    strm.flush_pending();
                    if (strm.avail_out == 0)
                    {
                        last_flush = - 1; // avoid BUF_ERROR at next call, see above
                        return Z_OK;
                    }
                }
            }

            if (flush != Z_FINISH)
                return Z_OK;
            if (noheader != 0)
                return Z_STREAM_END;

            // Write the zlib trailer (adler32)
            //Nanook - no trailer
            //putShortMSB((int) (SupportClass.URShift(strm.adler, 16)));
            //putShortMSB((int) (strm.adler & 0xffff));
            strm.flush_pending();

            // If avail_out is zero, the application will call deflate again
            // to flush the rest.
            noheader = - 1; // write the trailer only once!
            return pending != 0?Z_OK:Z_STREAM_END;
        }