orx_priority_queue/
has_index.rs

1/// A struct which provides an index of type [usize].
2/// Index of the struct can be considered its unchanging id
3/// defined its position in a collection.
4///
5/// For instance consider a tour generation problem for cities in the collection {X, Y, Z}.
6/// Provided that this collection does not change, the cities can be identified by their indices:
7/// X => 0, Y => 1, Z => 2.
8///
9/// In certain algorithms, as well as, in certain priority queue implementations in this crate,
10/// this convention allows to replace a hashmap with an array.
11/// This may be useful in simplifying the algorithms and improving performance when
12/// the elements entering the queue are sampled from a closed and known set, as the cities above.
13pub trait HasIndex: Clone {
14    /// Returns the index of the element.
15    fn index(&self) -> usize;
16}
17
18impl HasIndex for usize {
19    #[inline(always)]
20    fn index(&self) -> usize {
21        *self
22    }
23}
24impl HasIndex for u64 {
25    #[inline(always)]
26    fn index(&self) -> usize {
27        *self as usize
28    }
29}
30impl HasIndex for u32 {
31    #[inline(always)]
32    fn index(&self) -> usize {
33        *self as usize
34    }
35}
36impl HasIndex for u16 {
37    #[inline(always)]
38    fn index(&self) -> usize {
39        *self as usize
40    }
41}
42impl HasIndex for u8 {
43    #[inline(always)]
44    fn index(&self) -> usize {
45        *self as usize
46    }
47}
orx_priority_queue/has_index.rs

orx_priority_queue/
has_index.rs
