moc 0.19.2

Library made to create and manipulate HEALPix Multi-Order Coverages maps (MOCs), see https://ivoa.net/documents/MOC/
Documentation 
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use std::mem;
use std::ops::Range;

pub fn flatten<T>(input: &mut Vec<Range<T>>) -> Vec<T> {
  let mut owned_input = Vec::<Range<T>>::new();
  // We swap the content referred by input with a new
  // allocated vector.
  // This fix the problem when ``input`` is freed by reaching out
  // the end of the caller scope.
  mem::swap(&mut owned_input, input);

  let len = owned_input.len() << 1;
  let cap = len;
  let ptr = owned_input.as_mut_ptr() as *mut T;

  mem::forget(owned_input);

  unsafe { Vec::from_raw_parts(ptr, len, cap) }
}

pub fn unflatten<T>(input: &mut Vec<T>) -> Vec<Range<T>> {
  let mut owned_input = Vec::<T>::new();
  // We swap the content refered by input with a new
  // allocated vector.
  // This fix the problem when ``input`` is freed by reaching out
  // the end of the caller scope.
  mem::swap(&mut owned_input, input);

  let len = owned_input.len() >> 1;
  let cap = len;
  let ptr = owned_input.as_mut_ptr() as *mut Range<T>;

  mem::forget(owned_input);

  unsafe { Vec::from_raw_parts(ptr, len, cap) }
}

#[cfg(test)]
mod tests {

  use crate::utils::{flatten, unflatten};
  use std::ops::Range;

  #[test]
  fn test_empty_flatten() {
    let mut empty_ranges = Vec::<Range<u64>>::new();

    let result = flatten(&mut empty_ranges);

    assert_eq!(result, Vec::<u64>::default());
  }

  #[test]
  fn test_empty_unflatten() {
    let mut empty_vec = Vec::<u64>::new();

    let result = unflatten(&mut empty_vec);

    assert_eq!(result, vec![]);
  }
}