trie_rs/internal_data_structure/naive_trie/
naive_trie_b_f_iter.rs

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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
use super::NaiveTrie;
use std::collections::VecDeque;

#[derive(Debug)]
/// Iterates over NaiveTrie in Breadth-First manner.
pub struct NaiveTrieBFIter<Label, Value> {
    unvisited: VecDeque<NaiveTrie<Label, Value>>,
}

impl<Label, Value> NaiveTrieBFIter<Label, Value> {
    pub fn new(iter_start: NaiveTrie<Label, Value>) -> Self {
        let mut unvisited = VecDeque::new();
        unvisited.push_back(iter_start);
        Self { unvisited }
    }
}

impl<Label: Ord, Value> Iterator for NaiveTrieBFIter<Label, Value> {
    type Item = NaiveTrie<Label, Value>;

    /// Returns:
    ///
    /// - None: All nodes are visited.
    /// - Some(NaiveTrie::Root): Root node.
    /// - Some(NaiveTrie::IntermOrLeaf): Intermediate or leaf node.
    /// - Some(NaiveTrie::PhantomSibling): Marker to represent "all siblings are iterated".
    fn next(&mut self) -> Option<Self::Item> {
        self.unvisited.pop_front().map(|mut trie| {
            match trie {
                NaiveTrie::Root(_) | NaiveTrie::IntermOrLeaf(_) => {
                    for child in trie.drain_children() {
                        self.unvisited.push_back(child);
                    }
                    self.unvisited.push_back(NaiveTrie::PhantomSibling);
                }
                NaiveTrie::PhantomSibling => {}
            };
            trie
        })
    }
}

#[cfg(test)]
mod bf_iter_tests {
    type NaiveTrie<T> = super::NaiveTrie<T, ()>;
    const TRUE: Option<()> = Some(());
    const FALSE: Option<()> = None;

    macro_rules! parameterized_tests {
        ($($name:ident: $value:expr,)*) => {
        $(
            #[test]
            fn $name() {
                let (words, expected_nodes) = $value;
                let mut trie = NaiveTrie::make_root();
                for word in words {
                    trie.push(word.bytes().into_iter(), ());
                }
                let nodes: Vec<NaiveTrie<u8>> = trie.into_iter().collect();
                assert_eq!(nodes.len(), expected_nodes.len());
                for i in 0..nodes.len() {
                    let node = &nodes[i];
                    let expected_node = &expected_nodes[i];

                    assert!(std::mem::discriminant(node) == std::mem::discriminant(expected_node));

                    if let NaiveTrie::IntermOrLeaf(n) = node {
                        assert_eq!(n.label, *expected_node.label());
                        assert_eq!(n.value.is_some(), expected_node.value().is_some());
                    }
                }
            }
        )*
        }
    }

    parameterized_tests! {
        t1: (
            Vec::<&str>::new(),
            vec![
                NaiveTrie::make_root(),
                // parent = root
                NaiveTrie::PhantomSibling,
            ]
        ),
        t2: (
            vec!["a"],
            vec![
                NaiveTrie::make_root(),
                // parent = root
                NaiveTrie::make_interm_or_leaf(b'a', TRUE),
                NaiveTrie::PhantomSibling,
                // parent = a
                NaiveTrie::PhantomSibling,
            ]
        ),
        t3: (
            vec!["a", "a"],
            vec![
                NaiveTrie::make_root(),
                // parent = root
                NaiveTrie::make_interm_or_leaf(b'a', TRUE),
                NaiveTrie::PhantomSibling,
                // parent = a
                NaiveTrie::PhantomSibling,
            ]
        ),
        t4: (
            // root
            //  |-----------------------+-----------------------+
            //  |                       |                       |
            //  a (term)                b                       Ph
            //  |---------+             |-----------------+
            //  |         |             |                 |
            //  n (term)  Ph            a                 Ph
            //  |                       |--------+
            //  |                       |        |
            //  Ph                      d (term) Ph
            //                          |
            //                          |
            //                          Ph
            vec!["a", "bad", "an"],
            vec![
                NaiveTrie::make_root(),
                // parent = root
                NaiveTrie::make_interm_or_leaf(b'a', TRUE),
                NaiveTrie::make_interm_or_leaf(b'b', FALSE),
                NaiveTrie::PhantomSibling,
                // parent = [a]
                NaiveTrie::make_interm_or_leaf(b'n', TRUE),
                NaiveTrie::PhantomSibling,
                // parent = b
                NaiveTrie::make_interm_or_leaf(b'a', FALSE),
                NaiveTrie::PhantomSibling,
                // parent = n
                NaiveTrie::PhantomSibling,
                // parent = b[a]d
                NaiveTrie::make_interm_or_leaf(b'd', TRUE),
                NaiveTrie::PhantomSibling,
                // parent = d
                NaiveTrie::PhantomSibling,
            ]
        ),
        t5: (
            // 'り' => 227, 130, 138
            // 'ん' => 227, 130, 147
            // 'ご' => 227, 129, 148
            vec!["a", "an", "りんご", "りんりん"],
            vec![
                NaiveTrie::make_root(),
                // parent = root
                NaiveTrie::make_interm_or_leaf(b'a', TRUE),
                NaiveTrie::make_interm_or_leaf(227, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = a
                NaiveTrie::make_interm_or_leaf(b'n', TRUE),
                NaiveTrie::PhantomSibling,
                // parent = [227] 130 138 (り)
                NaiveTrie::make_interm_or_leaf(130, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = n
                NaiveTrie::PhantomSibling,
                // parent = 227 [130] 138 (り)
                NaiveTrie::make_interm_or_leaf(138, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = 227 130 [138] (り)
                NaiveTrie::make_interm_or_leaf(227, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = [227] 130 147 (ん)
                NaiveTrie::make_interm_or_leaf(130, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = 227 [130] 147 (ん)
                NaiveTrie::make_interm_or_leaf(147, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = 227 130 [147] (ん)
                NaiveTrie::make_interm_or_leaf(227, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = [227] _ _ (ご or り)
                NaiveTrie::make_interm_or_leaf(129, FALSE),
                NaiveTrie::make_interm_or_leaf(130, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = 227 [129] 148 (ご)
                NaiveTrie::make_interm_or_leaf(148, TRUE),
                NaiveTrie::PhantomSibling,
                // parent = 227 [130] 138 (り)
                NaiveTrie::make_interm_or_leaf(138, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = 227 129 [148] (ご)
                NaiveTrie::PhantomSibling,
                // parent = 227 130 [138] (り)
                NaiveTrie::make_interm_or_leaf(227, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = [227] 130 147 (ん)
                NaiveTrie::make_interm_or_leaf(130, FALSE),
                NaiveTrie::PhantomSibling,
                // parent = 227 [130] 147 (ん)
                NaiveTrie::make_interm_or_leaf(147, TRUE),
                NaiveTrie::PhantomSibling,
                // parent = 227 130 [147] (ん)
                NaiveTrie::PhantomSibling,
            ]
        ),
    }
}