denehoffman / oxyroot

Another attempt to make library reading and writing of `.root` binary files which are commonly used in particle physics

oxyroot

Another attempt to make library reading and writing .root binary files which are commonly used in particle physics

Inspiration

To make this library :

• heavy inspiration taken from groot for reading root file, even the code organisation
• inspiration taken from uproot to provide branch interface (for reading basket buffer)

Limitations

For now:

• only writing of primitive types is supported (i.e. i32, f64, bool, String, Fixed length arrays). Vec is also supported.
• can only write uncompressed file

See also

Another rust implementation of a root reader is root-io.

Getting started

Example: Iter over a branch tree containing i32 values

use oxyroot::RootFile;
let s = "examples/from_uproot/data/HZZ.root";
let tree = RootFile::open(s).unwrap().get_tree("events").unwrap();
let NJet = tree.branch("NJet").unwrap().as_iter::<i32>();
NJet.for_each( | v| trace!("v = {v}"));

# Example: Write i32 values in a branch

use oxyroot::{RootFile, WriterTree};
let s = "/tmp/simple.root";
let mut file = RootFile::create(s).expect("Can not create file");
let mut tree = WriterTree::new("mytree");
let it = (0..15);
tree.new_branch("it", it);
tree.write( & mut file).expect("Can not write tree");
file.close().expect("Can not close file");

Example: Iter over a branch tree containing Vec<i32> (aka std::vector<int32_t>) values

use oxyroot::RootFile;
let s = "tests/stl_containers/stl_containers.root";
let tree = RootFile::open(s).unwrap().get_tree("tree").unwrap();
let vector_int32 = tree.branch("vector_int32")
.unwrap().as_iter::<Vec<i32> > ()
.collect::<Vec<_ > > ();
assert_eq!(
    vector_int32,
    [
        vec![1],
        vec![1, 2],
        vec![1, 2, 3],
        vec![1, 2, 3, 4],
        vec![1, 2, 3, 4, 5]
    ]
);

Feature

oxyroot use flate2 to decompress zlib compressed data. The default backend is miniz_oxide, pure Rust crate.
If you want maximum performance, you can use the zlib-ng C library:

[dependencies]
oxyroot = { version = "0.1", features = ["zlib-ng"] }