1// This file is part of ICU4X. For terms of use, please see the file
2// called LICENSE at the top level of the ICU4X source tree
3// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5use crate::codepointtrie::CodePointMapRange;
6
7/// This is an iterator that coalesces adjacent ranges in an iterator over code
8/// point ranges
9pub(crate) struct RangeListIteratorCoalescer<I, T> {
10 iter: I,
11 peek: Option<CodePointMapRange<T>>,
12}
13
14impl<I, T: Eq> RangeListIteratorCoalescer<I, T>
15where
16 I: Iterator<Item = CodePointMapRange<T>>,
17{
18 pub fn new(iter: I) -> Self {
19 Self { iter, peek: None }
20 }
21}
22
23impl<I, T: Eq> Iterator for RangeListIteratorCoalescer<I, T>
24where
25 I: Iterator<Item = CodePointMapRange<T>>,
26{
27 type Item = CodePointMapRange<T>;
28
29 fn next(&mut self) -> Option<Self::Item> {
30 // Get the initial range we're working with: either a leftover
31 // range from last time, or the next range
32 let mut ret = if let Some(peek) = self.peek.take() {
33 peek
34 } else if let Some(next) = self.iter.next() {
35 next
36 } else {
37 // No ranges, exit early
38 return None;
39 };
40
41 // Keep pulling ranges
42 #[allow(clippy::while_let_on_iterator)]
43 // can't move the iterator, also we want it to be explicit that we're not draining the iterator
44 while let Some(next) = self.iter.next() {
45 if *next.range.start() == ret.range.end() + 1 && next.value == ret.value {
46 // Range has no gap, coalesce
47 ret.range = *ret.range.start()..=*next.range.end();
48 } else {
49 // Range has a gap, return what we have so far, update
50 // peek
51 self.peek = Some(next);
52 return Some(ret);
53 }
54 }
55
56 // Ran out of elements, exit
57 Some(ret)
58 }
59}
60
61#[cfg(test)]
62mod tests {
63 use core::fmt::Debug;
64 use icu::collections::codepointinvlist::CodePointInversionListBuilder;
65 use icu::collections::codepointtrie::TrieValue;
66 use icu::properties::maps::{self, CodePointMapDataBorrowed};
67 use icu::properties::sets::{self, CodePointSetDataBorrowed};
68 use icu::properties::{GeneralCategory, Script};
69
70 fn test_set(data: CodePointSetDataBorrowed<'static>, name: &str) {
71 let mut builder = CodePointInversionListBuilder::new();
72 let mut builder_complement = CodePointInversionListBuilder::new();
73
74 for range in data.iter_ranges() {
75 builder.add_range32(&range)
76 }
77
78 for range in data.iter_ranges_complemented() {
79 builder_complement.add_range32(&range)
80 }
81
82 builder.complement();
83 let set1 = builder.build();
84 let set2 = builder_complement.build();
85 assert_eq!(set1, set2, "Set {name} failed to complement correctly");
86 }
87
88 fn test_map<T: TrieValue + Debug>(
89 data: &CodePointMapDataBorrowed<'static, T>,
90 value: T,
91 name: &str,
92 ) {
93 let mut builder = CodePointInversionListBuilder::new();
94 let mut builder_complement = CodePointInversionListBuilder::new();
95
96 for range in data.iter_ranges_for_value(value) {
97 builder.add_range32(&range)
98 }
99
100 for range in data.iter_ranges_for_value_complemented(value) {
101 builder_complement.add_range32(&range)
102 }
103
104 builder.complement();
105 let set1 = builder.build();
106 let set2 = builder_complement.build();
107 assert_eq!(
108 set1, set2,
109 "Map {name} failed to complement correctly with value {value:?}"
110 );
111 }
112
113 #[test]
114 fn test_complement_sets() {
115 // Stress test the RangeListIteratorComplementer logic by ensuring it works for
116 // a whole bunch of binary properties
117 test_set(sets::ascii_hex_digit(), "ASCII_Hex_Digit");
118 test_set(sets::alnum(), "Alnum");
119 test_set(sets::alphabetic(), "Alphabetic");
120 test_set(sets::bidi_control(), "Bidi_Control");
121 test_set(sets::bidi_mirrored(), "Bidi_Mirrored");
122 test_set(sets::blank(), "Blank");
123 test_set(sets::cased(), "Cased");
124 test_set(sets::case_ignorable(), "Case_Ignorable");
125 test_set(
126 sets::full_composition_exclusion(),
127 "Full_Composition_Exclusion",
128 );
129 test_set(sets::changes_when_casefolded(), "Changes_When_Casefolded");
130 test_set(sets::changes_when_casemapped(), "Changes_When_Casemapped");
131 test_set(
132 sets::changes_when_nfkc_casefolded(),
133 "Changes_When_NFKC_Casefolded",
134 );
135 test_set(sets::changes_when_lowercased(), "Changes_When_Lowercased");
136 test_set(sets::changes_when_titlecased(), "Changes_When_Titlecased");
137 test_set(sets::changes_when_uppercased(), "Changes_When_Uppercased");
138 test_set(sets::dash(), "Dash");
139 test_set(sets::deprecated(), "Deprecated");
140 test_set(
141 sets::default_ignorable_code_point(),
142 "Default_Ignorable_Code_Point",
143 );
144 test_set(sets::diacritic(), "Diacritic");
145 test_set(sets::emoji_modifier_base(), "Emoji_Modifier_Base");
146 test_set(sets::emoji_component(), "Emoji_Component");
147 test_set(sets::emoji_modifier(), "Emoji_Modifier");
148 test_set(sets::emoji(), "Emoji");
149 test_set(sets::emoji_presentation(), "Emoji_Presentation");
150 test_set(sets::extender(), "Extender");
151 test_set(sets::extended_pictographic(), "Extended_Pictographic");
152 test_set(sets::graph(), "Graph");
153 test_set(sets::grapheme_base(), "Grapheme_Base");
154 test_set(sets::grapheme_extend(), "Grapheme_Extend");
155 test_set(sets::grapheme_link(), "Grapheme_Link");
156 test_set(sets::hex_digit(), "Hex_Digit");
157 test_set(sets::hyphen(), "Hyphen");
158 test_set(sets::id_continue(), "Id_Continue");
159 test_set(sets::ideographic(), "Ideographic");
160 test_set(sets::id_start(), "Id_Start");
161 test_set(sets::ids_binary_operator(), "Ids_Binary_Operator");
162 test_set(sets::ids_trinary_operator(), "Ids_Trinary_Operator");
163 test_set(sets::join_control(), "Join_Control");
164 test_set(sets::logical_order_exception(), "Logical_Order_Exception");
165 test_set(sets::lowercase(), "Lowercase");
166 test_set(sets::math(), "Math");
167 test_set(sets::noncharacter_code_point(), "Noncharacter_Code_Point");
168 test_set(sets::nfc_inert(), "NFC_Inert");
169 test_set(sets::nfd_inert(), "NFD_Inert");
170 test_set(sets::nfkc_inert(), "NFKC_Inert");
171 test_set(sets::nfkd_inert(), "NFKD_Inert");
172 test_set(sets::pattern_syntax(), "Pattern_Syntax");
173 test_set(sets::pattern_white_space(), "Pattern_White_Space");
174 test_set(
175 sets::prepended_concatenation_mark(),
176 "Prepended_Concatenation_Mark",
177 );
178 test_set(sets::print(), "Print");
179 test_set(sets::quotation_mark(), "Quotation_Mark");
180 test_set(sets::radical(), "Radical");
181 test_set(sets::regional_indicator(), "Regional_Indicator");
182 test_set(sets::soft_dotted(), "Soft_Dotted");
183 test_set(sets::segment_starter(), "Segment_Starter");
184 test_set(sets::case_sensitive(), "Case_Sensitive");
185 test_set(sets::sentence_terminal(), "Sentence_Terminal");
186 test_set(sets::terminal_punctuation(), "Terminal_Punctuation");
187 test_set(sets::unified_ideograph(), "Unified_Ideograph");
188 test_set(sets::uppercase(), "Uppercase");
189 test_set(sets::variation_selector(), "Variation_Selector");
190 test_set(sets::white_space(), "White_Space");
191 test_set(sets::xdigit(), "Xdigit");
192 test_set(sets::xid_continue(), "XID_Continue");
193 test_set(sets::xid_start(), "XID_Start");
194 }
195
196 #[test]
197 fn test_complement_maps() {
198 let gc = maps::general_category();
199 let script = maps::script();
200 test_map(&gc, GeneralCategory::UppercaseLetter, "gc");
201 test_map(&gc, GeneralCategory::OtherPunctuation, "gc");
202 test_map(&script, Script::Devanagari, "script");
203 test_map(&script, Script::Latin, "script");
204 test_map(&script, Script::Common, "script");
205 }
206}
207