Compress the String str
blocks specifies the block size to be used for compression. It
should be a value between 1 and 9 inclusive, and the actual block size used
is 100000 x this value
work controls how the compression phase behaves when presented
with worst case, highly repetitive, input data.Allowable values range from
0 to 250 inclusive
Uncompress the String str
If small is true, the library will use an alternative
decompression algorithm which uses less memory but at the cost of
decompressing more slowly