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# xdrfile
Read and write xdr trajectory files in .xtc and .trr file format

This crate is mainly intended to be a wrapper around the GROMACS libxdrfile
XTC library and provides basic functionality to read and write xtc and trr
files with a safe api.

## Examples
### Basic usage
```rust
use xdrfile::*;

fn main() -> Result<()> {
    // get a handle to the file
    let mut trj = XTCTrajectory::open_read("tests/1l2y.xtc")?;

    // find number of atoms in the file
    let num_atoms = trj.get_num_atoms()?;

    // a frame object is used to get to read or write from a trajectory
    // without instantiating data arrays for every step
    let mut frame = Frame::with_len(num_atoms);

    // read the first frame of the trajectory
    trj.read(&mut frame)?;

    assert_eq!(frame.step, 1);
    assert_eq!(frame.len(), num_atoms);

    let first_atom_coords = frame.coords[0];
    assert_eq!(first_atom_coords, [-0.8901, 0.4127, -0.055499997]);

    Ok(())
}
```

### Frame iteration
For convenience, the trajectory implementations provide "into_iter" to
be turned into an iterator that yields Rc<Frame>. If a frame is not kept
during iteration, the Iterator reuses it for better performance (and hence,
Rc is required)

```rust
use xdrfile::*;

fn main() -> Result<()> {
    // get a handle to the file
    let trj = XTCTrajectory::open_read("tests/1l2y.xtc")?;

    // iterate over all frames
    for (idx, result) in trj.into_iter().enumerate() {
        let frame = result?;
        println!("{}", frame.time);
        assert_eq!(idx+1, frame.step);
    }
    Ok(())
}
```

## xdrfile
Uses the lowlevel xdrfile c library version 1.1.4 with some minor fixes and additions copied from [mdtraj](https://github.com/mdtraj/mdtraj).



## License
Licensed under LGPL because this is what the underlying c library (xdrfile) uses