Plupload.PngEncoder.DeflaterEngine.DeflateSlow C# (CSharp) Method

        bool DeflateSlow(bool flush, bool finish)
        {
            if (lookahead < MIN_LOOKAHEAD && !flush) {
                return false;
            }

            while (lookahead >= MIN_LOOKAHEAD || flush) {
                if (lookahead == 0) {
                    if (prevAvailable) {
                        huffman.TallyLit(window[strstart - 1] & 0xff);
                    }
                    prevAvailable = false;

                    // We are flushing everything
            #if DebugDeflation
                    if (DeflaterConstants.DEBUGGING && !flush)
                    {
                        throw new SharpZipBaseException("Not flushing, but no lookahead");
                    }
            #endif
                    huffman.FlushBlock(window, blockStart, strstart - blockStart,
                        finish);
                    blockStart = strstart;
                    return false;
                }

                if (strstart >= 2 * WSIZE - MIN_LOOKAHEAD) {
                    /* slide window, as FindLongestMatch needs this.
                     * This should only happen when flushing and the window
                     * is almost full.
                     */
                    SlideWindow();
                }

                int prevMatch = matchStart;
                int prevLen = matchLen;
                if (lookahead >= MIN_MATCH) {

                    int hashHead = InsertString();

                    if (strategy != DeflateStrategy.HuffmanOnly &&
                        hashHead != 0 &&
                        strstart - hashHead <= MAX_DIST &&
                        FindLongestMatch(hashHead)) {

                        // longestMatch sets matchStart and matchLen

                        // Discard match if too small and too far away
                        if (matchLen <= 5 && (strategy == DeflateStrategy.Filtered || (matchLen == MIN_MATCH && strstart - matchStart > TooFar))) {
                            matchLen = MIN_MATCH - 1;
                        }
                    }
                }

                // previous match was better
                if ((prevLen >= MIN_MATCH) && (matchLen <= prevLen)) {
            #if DebugDeflation
                    if (DeflaterConstants.DEBUGGING)
                    {
                       for (int i = 0 ; i < matchLen; i++) {
                          if (window[strstart-1+i] != window[prevMatch + i])
                             throw new SharpZipBaseException();
                        }
                    }
            #endif
                    huffman.TallyDist(strstart - 1 - prevMatch, prevLen);
                    prevLen -= 2;
                    do {
                        strstart++;
                        lookahead--;
                        if (lookahead >= MIN_MATCH) {
                            InsertString();
                        }
                    } while (--prevLen > 0);

                    strstart++;
                    lookahead--;
                    prevAvailable = false;
                    matchLen = MIN_MATCH - 1;
                } else {
                    if (prevAvailable) {
                        huffman.TallyLit(window[strstart - 1] & 0xff);
                    }
                    prevAvailable = true;
                    strstart++;
                    lookahead--;
                }

                if (huffman.IsFull()) {
                    int len = strstart - blockStart;
                    if (prevAvailable) {
                        len--;
                    }
                    bool lastBlock = (finish && (lookahead == 0) && !prevAvailable);
                    huffman.FlushBlock(window, blockStart, len, lastBlock);
                    blockStart += len;
                    return !lastBlock;
                }
            }
            return true;
        }