solverforge-scoring 0.8.1

Incremental constraint scoring for SolverForge
Documentation 
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// Overlapping joiner for interval overlap detection.

use std::marker::PhantomData;

use super::Joiner;

/* Creates a joiner that matches when two intervals overlap.

Two intervals [start_a, end_a) and [start_b, end_b) overlap if:
- start_a < end_b AND start_b < end_a

This uses half-open intervals: the start is inclusive, the end is exclusive.

# Example

```
use solverforge_scoring::stream::joiner::{Joiner, overlapping};

#[derive(Clone)]
struct Shift { start: i64, end: i64 }

let overlap = overlapping(
|s: &Shift| s.start,
|s: &Shift| s.end,
|s: &Shift| s.start,
|s: &Shift| s.end
);

// Overlapping shifts: [0, 10) and [5, 15) overlap at [5, 10)
assert!(overlap.matches(
&Shift { start: 0, end: 10 },
&Shift { start: 5, end: 15 }
));

// Non-overlapping shifts: [0, 10) and [10, 20) touch but don't overlap
assert!(!overlap.matches(
&Shift { start: 0, end: 10 },
&Shift { start: 10, end: 20 }
));

// Non-overlapping shifts: [0, 5) and [10, 15) are disjoint
assert!(!overlap.matches(
&Shift { start: 0, end: 5 },
&Shift { start: 10, end: 15 }
));
```
*/
pub fn overlapping<A, B, T, Fsa, Fea, Fsb, Feb>(
    start_a: Fsa,
    end_a: Fea,
    start_b: Fsb,
    end_b: Feb,
) -> OverlappingJoiner<Fsa, Fea, Fsb, Feb, T>
where
    T: Ord,
    Fsa: Fn(&A) -> T + Send + Sync,
    Fea: Fn(&A) -> T + Send + Sync,
    Fsb: Fn(&B) -> T + Send + Sync,
    Feb: Fn(&B) -> T + Send + Sync,
{
    OverlappingJoiner {
        start_a,
        end_a,
        start_b,
        end_b,
        _phantom: PhantomData,
    }
}

/* A joiner that matches when two intervals overlap.

Created by the [`overlapping()`] function.
*/
pub struct OverlappingJoiner<Fsa, Fea, Fsb, Feb, T> {
    start_a: Fsa,
    end_a: Fea,
    start_b: Fsb,
    end_b: Feb,
    _phantom: PhantomData<fn() -> T>,
}

impl<A, B, T, Fsa, Fea, Fsb, Feb> Joiner<A, B> for OverlappingJoiner<Fsa, Fea, Fsb, Feb, T>
where
    T: Ord,
    Fsa: Fn(&A) -> T + Send + Sync,
    Fea: Fn(&A) -> T + Send + Sync,
    Fsb: Fn(&B) -> T + Send + Sync,
    Feb: Fn(&B) -> T + Send + Sync,
{
    #[inline]
    fn matches(&self, a: &A, b: &B) -> bool {
        let start_a = (self.start_a)(a);
        let end_a = (self.end_a)(a);
        let start_b = (self.start_b)(b);
        let end_b = (self.end_b)(b);

        // Half-open interval overlap: [start_a, end_a) ∩ [start_b, end_b) ≠ ∅
        // iff start_a < end_b AND start_b < end_a
        start_a < end_b && start_b < end_a
    }
}