solverforge_scoring/stream/joiner/
overlapping.rs

1// Overlapping joiner for interval overlap detection.
2
3use std::marker::PhantomData;
4
5use super::Joiner;
6
7/* Creates a joiner that matches when two intervals overlap.
8
9Two intervals [start_a, end_a) and [start_b, end_b) overlap if:
10- start_a < end_b AND start_b < end_a
11
12This uses half-open intervals: the start is inclusive, the end is exclusive.
13
14# Example
15
16```
17use solverforge_scoring::stream::joiner::{Joiner, overlapping};
18
19#[derive(Clone)]
20struct Shift { start: i64, end: i64 }
21
22let overlap = overlapping(
23|s: &Shift| s.start,
24|s: &Shift| s.end,
25|s: &Shift| s.start,
26|s: &Shift| s.end
27);
28
29// Overlapping shifts: [0, 10) and [5, 15) overlap at [5, 10)
30assert!(overlap.matches(
31&Shift { start: 0, end: 10 },
32&Shift { start: 5, end: 15 }
33));
34
35// Non-overlapping shifts: [0, 10) and [10, 20) touch but don't overlap
36assert!(!overlap.matches(
37&Shift { start: 0, end: 10 },
38&Shift { start: 10, end: 20 }
39));
40
41// Non-overlapping shifts: [0, 5) and [10, 15) are disjoint
42assert!(!overlap.matches(
43&Shift { start: 0, end: 5 },
44&Shift { start: 10, end: 15 }
45));
46```
47*/
48pub fn overlapping<T, Fsa, Fea, Fsb, Feb>(
49    start_a: Fsa,
50    end_a: Fea,
51    start_b: Fsb,
52    end_b: Feb,
53) -> OverlappingJoiner<Fsa, Fea, Fsb, Feb, T>
54where
55    T: Ord,
56    Fsa: Send + Sync,
57    Fea: Send + Sync,
58    Fsb: Send + Sync,
59    Feb: Send + Sync,
60{
61    OverlappingJoiner {
62        start_a,
63        end_a,
64        start_b,
65        end_b,
66        _phantom: PhantomData,
67    }
68}
69
70/* Creates a joiner matching when the left row's interval overlaps the right's.
71
72Row-aware form of [`overlapping`]: start/end closures for the left side
73receive the whole borrowed row; the right side sees only the new entity.
74Half-open endpoint semantics are unchanged: `[s, e)` overlaps iff
75`start_row < end_c AND start_c < end_row`. Bound extractors stay
76accessible for interval candidate planning.
77*/
78pub fn overlap_on<T, LS, LE, CS, CE>(
79    start_row: LS,
80    end_row: LE,
81    start_c: CS,
82    end_c: CE,
83) -> OverlappingJoiner<LS, LE, CS, CE, T>
84where
85    T: Ord,
86    LS: Send + Sync,
87    LE: Send + Sync,
88    CS: Send + Sync,
89    CE: Send + Sync,
90{
91    OverlappingJoiner {
92        start_a: start_row,
93        end_a: end_row,
94        start_b: start_c,
95        end_b: end_c,
96        _phantom: PhantomData,
97    }
98}
99
100/* A joiner that matches when two intervals overlap.
101
102Created by the [`overlapping()`] function.
103*/
104pub struct OverlappingJoiner<Fsa, Fea, Fsb, Feb, T> {
105    pub(super) start_a: Fsa,
106    pub(super) end_a: Fea,
107    pub(super) start_b: Fsb,
108    pub(super) end_b: Feb,
109    _phantom: PhantomData<fn() -> T>,
110}
111
112impl<Fsa, Fea, Fsb, Feb, T> OverlappingJoiner<Fsa, Fea, Fsb, Feb, T> {
113    /// Compose without prematurely binding a borrowed row lifetime.
114    pub fn and<J>(self, other: J) -> super::AndJoiner<Self, J> {
115        super::AndJoiner {
116            first: self,
117            second: other,
118        }
119    }
120    /* Consumes the joiner and returns the bound extractors for index planning. */
121    #[inline]
122    pub fn into_bounds(self) -> (Fsa, Fea, Fsb, Feb) {
123        (self.start_a, self.end_a, self.start_b, self.end_b)
124    }
125}
126
127impl<A, B, T, Fsa, Fea, Fsb, Feb> Joiner<A, B> for OverlappingJoiner<Fsa, Fea, Fsb, Feb, T>
128where
129    T: Ord,
130    Fsa: Fn(&A) -> T + Send + Sync,
131    Fea: Fn(&A) -> T + Send + Sync,
132    Fsb: Fn(&B) -> T + Send + Sync,
133    Feb: Fn(&B) -> T + Send + Sync,
134{
135    #[inline]
136    fn matches(&self, a: &A, b: &B) -> bool {
137        let start_a = (self.start_a)(a);
138        let end_a = (self.end_a)(a);
139        let start_b = (self.start_b)(b);
140        let end_b = (self.end_b)(b);
141
142        // Half-open interval overlap: [start_a, end_a) ∩ [start_b, end_b) ≠ ∅
143        // iff start_a < end_b AND start_b < end_a
144        start_a < end_b && start_b < end_a
145    }
146}
solverforge_scoring/stream/joiner/overlapping.rs

solverforge_scoring/stream/joiner/
overlapping.rs
