dictionary which is empty, and that it will always be
invalid at this place.
- 17 : bitstream version. If the first byte is 17, the next byte
- gives the bitstream version (version 1 only). If the first byte
- is not 17, the bitstream version is 0.
+ 17 : bitstream version. If the first byte is 17, and compressed
+ stream length is at least 5 bytes (length of shortest possible
+ versioned bitstream), the next byte gives the bitstream version
+ (version 1 only).
+ Otherwise, the bitstream version is 0.
18..21 : copy 0..3 literals
state = (byte - 17) = 0..3 [ copy <state> literals ]