will automatically truncate or repeat input as needed,
to create the requested nb of blocks.
default: nb of files, eventually increased appropriately if blockSize is set
measures :
- compression ratio with / without dictionary
- create one dictionary per block
- memory budget for dictionaries
- decompression speed, using one different dictionary per block
current limitations :
- only one file
- 4K blocks only
- automatic dictionary built with 4K size
dictionary can be selected on command line, with -D
