protected void encode()

in pdfbox/src/main/java/org/apache/pdfbox/filter/RunLengthDecodeFilter.java [78:189]
102 lines of code
13 McCabe index (conditional complexity)

    protected void encode(InputStream input, OutputStream encoded, COSDictionary parameters)
            throws IOException
    {
        // Not used in PDFBox except for testing the decoder.
        int lastVal = -1;
        int byt;
        int count = 0;
        boolean equality = false;

        // buffer for "unequal" runs, size between 2 and 128
        byte[] buf = new byte[128];

        while ((byt = input.read()) != -1)
        {
            if (lastVal == -1)
            {
                // first time
                lastVal = byt;
                count = 1;
            }
            else
            {
                if (count == 128)
                {
                    if (equality)
                    {
                        // max length of equals
                        encoded.write(129); // = 257 - 128
                        encoded.write(lastVal);
                    }
                    else
                    {
                        // max length of unequals
                        encoded.write(127);
                        encoded.write(buf, 0, 128);
                    }
                    equality = false;
                    lastVal = byt;
                    count = 1;
                }
                else if (count == 1)
                {
                    if (byt == lastVal)
                    {
                        equality = true;
                    }
                    else
                    {
                        buf[0] = (byte) lastVal;
                        buf[1] = (byte) byt;
                        lastVal = byt;
                    }
                    count = 2;
                }
                else
                {
                    // 1 < count < 128
                    if (byt == lastVal)
                    {
                        if (equality)
                        {
                            ++count;
                        }
                        else
                        {
                            // write all we got except the last
                            encoded.write(count - 2);
                            encoded.write(buf, 0, count - 1);
                            count = 2;
                            equality = true;
                        }
                    }
                    else
                    {
                        if (equality)
                        {
                            // equality ends here
                            encoded.write(257 - count);
                            encoded.write(lastVal);
                            equality = false;
                            count = 1;
                        }
                        else
                        {
                            buf[count] = (byte) byt;
                            ++count;
                        }
                        lastVal = byt;
                    }
                }
            }
        }
        if (count > 0)
        {
            if (count == 1)
            {
                encoded.write(0);
                encoded.write(lastVal);
            }
            else if (equality)
            {
                encoded.write(257 - count);
                encoded.write(lastVal);
            }
            else
            {
                encoded.write(count - 1);
                encoded.write(buf, 0, count);
            }
        }
        encoded.write(RUN_LENGTH_EOD);
    }