mitsein 0.9.0

Strongly typed APIs for non-empty collections, slices, and iterators.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

#![cfg(feature = "alloc")]

use core::borrow::Borrow;
use core::ops::{Bound, RangeBounds};

use crate::segment::range::{IntoRangeBounds, UnorderedError};

pub trait OptionExt<N> {
    fn contains<Q>(&self, key: &Q) -> bool
    where
        N: Borrow<Q> + Ord,
        Q: Ord + ?Sized;
}

impl<N> OptionExt<N> for Option<ItemRange<N>> {
    fn contains<Q>(&self, key: &Q) -> bool
    where
        N: Borrow<Q> + Ord,
        Q: Ord + ?Sized,
    {
        self.as_ref().is_some_and(|range| range.contains(key))
    }
}

#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub struct ItemRange<N> {
    start: Bound<N>,
    end: Bound<N>,
}

impl<N> ItemRange<N> {
    pub(crate) fn unchecked(start: Bound<N>, end: Bound<N>) -> Self {
        ItemRange { start, end }
    }

    pub fn bounded(start: N, end: N) -> Result<Self, UnorderedError<N>>
    where
        N: Ord,
    {
        if start <= end {
            Ok(ItemRange::unchecked(
                Bound::Included(start),
                Bound::Excluded(end),
            ))
        }
        else {
            Err(UnorderedError(start, end))
        }
    }

    pub fn empty_at(at: N) -> Self
    where
        N: Clone,
    {
        ItemRange::unchecked(Bound::Included(at.clone()), Bound::Excluded(at))
    }

    pub fn retain_in_range<'a, F>(&'a self, mut f: F) -> impl 'a + FnMut(&N) -> bool
    where
        N: Ord,
        F: 'a + FnMut(&N) -> bool,
    {
        let mut by_key_value = self.retain_key_value_in_range(move |key, _| f(key));
        move |item| by_key_value(item, &mut ())
    }

    pub fn retain_key_value_in_range<'a, T, F>(
        &'a self,
        mut f: F,
    ) -> impl 'a + FnMut(&N, &mut T) -> bool
    where
        N: Ord,
        F: 'a + FnMut(&N, &mut T) -> bool,
    {
        move |key, value| {
            if self.contains(key) {
                f(key, value)
            }
            else {
                true
            }
        }
    }

    pub fn as_ref(&self) -> ItemRange<&N> {
        ItemRange::unchecked(self.start.as_ref(), self.end.as_ref())
    }

    pub fn borrow<Q>(&self) -> ItemRange<&Q>
    where
        N: Borrow<Q>,
        Q: ?Sized,
    {
        ItemRange::unchecked(
            self.start.as_ref().map(N::borrow),
            self.end.as_ref().map(N::borrow),
        )
    }

    pub fn contains<Q>(&self, key: &Q) -> bool
    where
        N: Borrow<Q> + Ord,
        Q: Ord + ?Sized,
    {
        RangeBounds::contains(&self.borrow::<Q>(), key)
    }
}

impl<N> IntoRangeBounds<N> for ItemRange<N> {
    fn into_bounds(self) -> (Bound<N>, Bound<N>) {
        let ItemRange { start, end } = self;
        (start, end)
    }
}

impl<N> ItemRange<&'_ N> {
    pub fn cloned(&self) -> ItemRange<N>
    where
        N: Clone,
    {
        ItemRange::unchecked(self.start.cloned(), self.end.cloned())
    }
}

impl<N> RangeBounds<N> for ItemRange<N> {
    fn start_bound(&self) -> Bound<&N> {
        self.start.as_ref()
    }

    fn end_bound(&self) -> Bound<&N> {
        self.end.as_ref()
    }
}

impl<N> RangeBounds<N> for ItemRange<&'_ N>
where
    N: ?Sized,
{
    fn start_bound(&self) -> Bound<&N> {
        self.start
    }

    fn end_bound(&self) -> Bound<&N> {
        self.end
    }
}