nifti 0.17.0

Rust implementation of the NIfTI file format
Documentation 
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//! Miscellaneous volume-related functions
use crate::error::{NiftiError, Result};
use num_traits::Zero;

pub fn hot_vector<T>(dim: usize, axis: usize, value: T) -> Vec<T>
where
    T: Zero,
    T: Clone,
{
    let mut v = vec![T::zero(); dim];
    v[axis] = value;
    v
}

pub fn coords_to_index(coords: &[u16], dim: &[u16]) -> Result<usize> {
    if coords.len() != dim.len() || coords.is_empty() {
        return Err(NiftiError::IncorrectVolumeDimensionality(
            dim.len() as u16,
            coords.len() as u16,
        ));
    }

    if !coords.iter().zip(dim).all(|(&i, &d)| i < d) {
        return Err(NiftiError::OutOfBounds(Vec::from(coords)));
    }

    let mut crds = coords.iter();
    let start = *crds.next_back().unwrap() as usize;
    let index = crds
        .zip(dim)
        .rev()
        .fold(start, |a, b| a * *b.1 as usize + *b.0 as usize);

    Ok(index)
}

#[cfg(test)]
mod tests {
    use super::coords_to_index;

    #[test]
    fn test_coords_to_index() {
        assert!(coords_to_index(&[0, 0], &[10, 10, 5]).is_err());
        assert!(coords_to_index(&[0, 0, 0, 0], &[10, 10, 5]).is_err());
        assert_eq!(coords_to_index(&[0, 0, 0], &[10, 10, 5]).unwrap(), 0);

        assert_eq!(coords_to_index(&[1, 0, 0], &[16, 16, 3]).unwrap(), 1);
        assert_eq!(coords_to_index(&[0, 1, 0], &[16, 16, 3]).unwrap(), 16);
        assert_eq!(coords_to_index(&[0, 0, 1], &[16, 16, 3]).unwrap(), 256);
        assert_eq!(coords_to_index(&[1, 1, 1], &[16, 16, 3]).unwrap(), 273);

        assert_eq!(
            coords_to_index(&[15, 15, 2], &[16, 16, 3]).unwrap(),
            16 * 16 * 3 - 1
        );

        assert!(coords_to_index(&[16, 15, 2], &[16, 16, 3]).is_err());
    }
}