icu_collections/
iterator_utils.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
// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

use crate::codepointtrie::CodePointMapRange;

/// This is an iterator that coalesces adjacent ranges in an iterator over code
/// point ranges
pub(crate) struct RangeListIteratorCoalescer<I, T> {
    iter: I,
    peek: Option<CodePointMapRange<T>>,
}

impl<I, T: Eq> RangeListIteratorCoalescer<I, T>
where
    I: Iterator<Item = CodePointMapRange<T>>,
{
    pub fn new(iter: I) -> Self {
        Self { iter, peek: None }
    }
}

impl<I, T: Eq> Iterator for RangeListIteratorCoalescer<I, T>
where
    I: Iterator<Item = CodePointMapRange<T>>,
{
    type Item = CodePointMapRange<T>;

    fn next(&mut self) -> Option<Self::Item> {
        // Get the initial range we're working with: either a leftover
        // range from last time, or the next range
        let mut ret = if let Some(peek) = self.peek.take() {
            peek
        } else if let Some(next) = self.iter.next() {
            next
        } else {
            // No ranges, exit early
            return None;
        };

        // Keep pulling ranges
        #[allow(clippy::while_let_on_iterator)]
        // can't move the iterator, also we want it to be explicit that we're not draining the iterator
        while let Some(next) = self.iter.next() {
            if *next.range.start() == ret.range.end() + 1 && next.value == ret.value {
                // Range has no gap, coalesce
                ret.range = *ret.range.start()..=*next.range.end();
            } else {
                // Range has a gap, return what we have so far, update
                // peek
                self.peek = Some(next);
                return Some(ret);
            }
        }

        // Ran out of elements, exit
        Some(ret)
    }
}

#[cfg(test)]
mod tests {
    use core::fmt::Debug;
    use icu::collections::codepointinvlist::CodePointInversionListBuilder;
    use icu::properties::props::{BinaryProperty, EnumeratedProperty};
    use icu::properties::{CodePointMapData, CodePointSetData};

    fn test_set<P: BinaryProperty>(name: &str) {
        let mut builder = CodePointInversionListBuilder::new();
        let mut builder_complement = CodePointInversionListBuilder::new();

        for range in CodePointSetData::new::<P>().iter_ranges() {
            builder.add_range32(range)
        }

        for range in CodePointSetData::new::<P>().iter_ranges_complemented() {
            builder_complement.add_range32(range)
        }

        builder.complement();
        let set1 = builder.build();
        let set2 = builder_complement.build();
        assert_eq!(set1, set2, "Set {name} failed to complement correctly");
    }

    fn test_map<T: EnumeratedProperty + Debug>(value: T, name: &str) {
        let mut builder = CodePointInversionListBuilder::new();
        let mut builder_complement = CodePointInversionListBuilder::new();

        for range in CodePointMapData::<T>::new().iter_ranges_for_value(value) {
            builder.add_range32(range)
        }

        for range in CodePointMapData::<T>::new().iter_ranges_for_value_complemented(value) {
            builder_complement.add_range32(range)
        }

        builder.complement();
        let set1 = builder.build();
        let set2 = builder_complement.build();
        assert_eq!(
            set1, set2,
            "Map {name} failed to complement correctly with value {value:?}"
        );
    }

    #[test]
    fn test_complement_sets() {
        use icu::properties::props::*;
        // Stress test the RangeListIteratorComplementer logic by ensuring it works for
        // a whole bunch of binary properties
        test_set::<AsciiHexDigit>("ASCII_Hex_Digit");
        test_set::<Alnum>("Alnum");
        test_set::<Alphabetic>("Alphabetic");
        test_set::<BidiControl>("Bidi_Control");
        test_set::<BidiMirrored>("Bidi_Mirrored");
        test_set::<Blank>("Blank");
        test_set::<Cased>("Cased");
        test_set::<CaseIgnorable>("Case_Ignorable");
        test_set::<FullCompositionExclusion>("Full_Composition_Exclusion");
        test_set::<ChangesWhenCasefolded>("Changes_When_Casefolded");
        test_set::<ChangesWhenCasemapped>("Changes_When_Casemapped");
        test_set::<ChangesWhenNfkcCasefolded>("Changes_When_NFKC_Casefolded");
        test_set::<ChangesWhenLowercased>("Changes_When_Lowercased");
        test_set::<ChangesWhenTitlecased>("Changes_When_Titlecased");
        test_set::<ChangesWhenUppercased>("Changes_When_Uppercased");
        test_set::<Dash>("Dash");
        test_set::<Deprecated>("Deprecated");
        test_set::<DefaultIgnorableCodePoint>("Default_Ignorable_Code_Point");
        test_set::<Diacritic>("Diacritic");
        test_set::<EmojiModifierBase>("Emoji_Modifier_Base");
        test_set::<EmojiComponent>("Emoji_Component");
        test_set::<EmojiModifier>("Emoji_Modifier");
        test_set::<Emoji>("Emoji");
        test_set::<EmojiPresentation>("Emoji_Presentation");
        test_set::<Extender>("Extender");
        test_set::<ExtendedPictographic>("Extended_Pictographic");
        test_set::<Graph>("Graph");
        test_set::<GraphemeBase>("Grapheme_Base");
        test_set::<GraphemeExtend>("Grapheme_Extend");
        test_set::<GraphemeLink>("Grapheme_Link");
        test_set::<HexDigit>("Hex_Digit");
        test_set::<Hyphen>("Hyphen");
        test_set::<IdContinue>("Id_Continue");
        test_set::<Ideographic>("Ideographic");
        test_set::<IdStart>("Id_Start");
        test_set::<IdsBinaryOperator>("Ids_Binary_Operator");
        test_set::<IdsTrinaryOperator>("Ids_Trinary_Operator");
        test_set::<JoinControl>("Join_Control");
        test_set::<LogicalOrderException>("Logical_Order_Exception");
        test_set::<Lowercase>("Lowercase");
        test_set::<Math>("Math");
        test_set::<NoncharacterCodePoint>("Noncharacter_Code_Point");
        test_set::<NfcInert>("NFC_Inert");
        test_set::<NfdInert>("NFD_Inert");
        test_set::<NfkcInert>("NFKC_Inert");
        test_set::<NfkdInert>("NFKD_Inert");
        test_set::<PatternSyntax>("Pattern_Syntax");
        test_set::<PatternWhiteSpace>("Pattern_White_Space");
        test_set::<PrependedConcatenationMark>("Prepended_Concatenation_Mark");
        test_set::<Print>("Print");
        test_set::<QuotationMark>("Quotation_Mark");
        test_set::<Radical>("Radical");
        test_set::<RegionalIndicator>("Regional_Indicator");
        test_set::<SoftDotted>("Soft_Dotted");
        test_set::<SegmentStarter>("Segment_Starter");
        test_set::<CaseSensitive>("Case_Sensitive");
        test_set::<SentenceTerminal>("Sentence_Terminal");
        test_set::<TerminalPunctuation>("Terminal_Punctuation");
        test_set::<UnifiedIdeograph>("Unified_Ideograph");
        test_set::<Uppercase>("Uppercase");
        test_set::<VariationSelector>("Variation_Selector");
        test_set::<WhiteSpace>("White_Space");
        test_set::<Xdigit>("Xdigit");
        test_set::<XidContinue>("XID_Continue");
        test_set::<XidStart>("XID_Start");
    }

    #[test]
    fn test_complement_maps() {
        use icu::properties::props::{GeneralCategory, Script};
        test_map(GeneralCategory::UppercaseLetter, "gc");
        test_map(GeneralCategory::OtherPunctuation, "gc");
        test_map(Script::Devanagari, "script");
        test_map(Script::Latin, "script");
        test_map(Script::Common, "script");
    }
}