http://qkpm2ov2rjhjkhfsftskqho77uj5rewd5y44unkf6cb7tdhaxwcvh2id.onion/books/dbpf/DBPF%20Compression%20-%20SC4D%20Encyclopaedia.html
$len = $this->read_UL4($handle);
// Read the next 5 bytes (they are not used in this code,
// and are simply read and stashed out of the way).
$garbagedata = fread($handle, 5);
// Decompress the chunk.
// We do $len - 9 here because we are ignoring the first 9 bytes
// of the chunk (4 for the length value itself, 5 for other data).
// See later for a description of $this->decompress.