This is partially a project to educate myself how things work. Beyond the educational aspect, the project is to add new compression algorithms to ROOT. It is based on previous work by Manuel Schiller, adding LZO and LZ4 to ROOT.
LZO should ship with your OS. otherwise: http://www.oberhumer.com/opensource/lzo/#download LZ4 is included in the repo. originally: https://github.com/Cyan4973/lz4 zopfli is forked (see below). originally:https://github.com/google/zopfli.git brotli is forkedly included. originally: https://github.com/google/brotli
Get zopfli and put it path/to/root-compression/zopfli.
Call make from path/to/root-compression.
Observe that this implicitly calls
cd path/to/root-compression/zopfli
make libzopfli
You should now have to shared libraries:
path/to/root-compression/libLzoRoot.so
path/to/root-compression/zopfli/libzopfli.so
path/to/root-compression/brotli/enc/libenc.so
path/to/root-compression/brotli/dec/libdec.so
Override the root default compression stuff by injecting the library into LD_PRELOAD:
cd path/to/root-compression
export LD_PRELOAD=$LD_PRELOAD:`pwd`/brotli/enc/libenc.so:`pwd`/brotli/dec/libdec.so:`pwd`/zopfli/libzopfli.so:`pwd`/libLzoRoot.so
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:`pwd`/brotli/enc:`pwd`/brotli/dec
test your setup by putting a root file with a TTree in it (at top level) as
org.root into the test subdirectory and run
cd path/to/root-compression/test
make
or
cd path/to/root-compression
make test
now you should have many many root files with your original TTree in various compressions.
I use zopfli from git@github.com:pseyfert/zopfli.git and the branch
myadditions. This is a fork from https://github.com/google/zopfli.git at
commit 89cf773beef75d7f4d6d378debdf299378c3314e.
facing the transition to automised tests (in the test-dev branch) I'd like to point to http://stackoverflow.com/questions/1490949/how-to-write-loop-in-makefile according to which one can specify the test range
make -C test size -j 10 LAST_LEVEL=4 # to only test compression levels 1..4
make -C test callgrind-write -j 20 ALGS="6 7" LEVELS="4 5" # test only zopfli and brotli, and only levels 4 and 5
Furthermore, one does not need to specify LD_PRELOAD and LD_LIBRARY_PATH by hand anymore to run tests.
see test/summary.txt