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/// Implement memeory safe indexing (circular indexing)
///
/// When the index is out of bound (being negative or out of bound), the index
/// will try to fetch the item from the other end of the vector as if it's a
/// cylinder or circular array
fn circular_index(mut idx: isize, length: isize) -> usize {
while idx.is_negative() {
idx += length;
}
(idx % length) as usize
}
#[cfg(test)]
mod circular_index {
use super::*;
#[test]
fn negative_index() {
assert_eq!(circular_index(-1, 3), 2);
assert_eq!(circular_index(-2, 3), 1);
assert_eq!(circular_index(-3, 3), 0);
assert_eq!(circular_index(-4, 3), 2);
assert_eq!(circular_index(-5, 3), 1);
assert_eq!(circular_index(-6, 3), 0);
assert_eq!(circular_index(-7, 3), 2);
assert_eq!(circular_index(-8, 3), 1);
assert_eq!(circular_index(-9, 3), 0);
}
#[test]
fn positve_index() {
assert_eq!(circular_index(0, 3), 0);
assert_eq!(circular_index(1, 3), 1);
assert_eq!(circular_index(2, 3), 2);
assert_eq!(circular_index(3, 3), 0);
assert_eq!(circular_index(4, 3), 1);
assert_eq!(circular_index(5, 3), 2);
assert_eq!(circular_index(6, 3), 0);
assert_eq!(circular_index(7, 3), 1);
assert_eq!(circular_index(8, 3), 2);
}
}
/// Circular Plane used in Universe traversing
pub(crate) mod plane;
/// Universe object used for simulation
pub(crate) mod universe;
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