Changes

If we're at position 1000 in our output, and we need to read in a new control byte because we've finished with the last one. The next data to look it is:

We read in a control byte: 0xFC. In binary, that's 11111100. That informs us that the current block of data has two compressed offsets (@ 2 bytes each), followed by 6 literal data bytes. Once we'd read in the next 10 bytes (the compressed data plus the literal data), we'd be ready to read in our next control byte and start again.