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// 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
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::collections::codepointtrie::TrieValue;
use icu::properties::maps::{self, CodePointMapDataBorrowed};
use icu::properties::sets::{self, CodePointSetDataBorrowed};
use icu::properties::{GeneralCategory, Script};
fn test_set(data: CodePointSetDataBorrowed<'static>, name: &str) {
let mut builder = CodePointInversionListBuilder::new();
let mut builder_complement = CodePointInversionListBuilder::new();
for range in data.iter_ranges() {
builder.add_range32(&range)
}
for range in data.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: TrieValue + Debug>(
data: &CodePointMapDataBorrowed<'static, T>,
value: T,
name: &str,
) {
let mut builder = CodePointInversionListBuilder::new();
let mut builder_complement = CodePointInversionListBuilder::new();
for range in data.iter_ranges_for_value(value) {
builder.add_range32(&range)
}
for range in data.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() {
// Stress test the RangeListIteratorComplementer logic by ensuring it works for
// a whole bunch of binary properties
test_set(sets::ascii_hex_digit(), "ASCII_Hex_Digit");
test_set(sets::alnum(), "Alnum");
test_set(sets::alphabetic(), "Alphabetic");
test_set(sets::bidi_control(), "Bidi_Control");
test_set(sets::bidi_mirrored(), "Bidi_Mirrored");
test_set(sets::blank(), "Blank");
test_set(sets::cased(), "Cased");
test_set(sets::case_ignorable(), "Case_Ignorable");
test_set(
sets::full_composition_exclusion(),
"Full_Composition_Exclusion",
);
test_set(sets::changes_when_casefolded(), "Changes_When_Casefolded");
test_set(sets::changes_when_casemapped(), "Changes_When_Casemapped");
test_set(
sets::changes_when_nfkc_casefolded(),
"Changes_When_NFKC_Casefolded",
);
test_set(sets::changes_when_lowercased(), "Changes_When_Lowercased");
test_set(sets::changes_when_titlecased(), "Changes_When_Titlecased");
test_set(sets::changes_when_uppercased(), "Changes_When_Uppercased");
test_set(sets::dash(), "Dash");
test_set(sets::deprecated(), "Deprecated");
test_set(
sets::default_ignorable_code_point(),
"Default_Ignorable_Code_Point",
);
test_set(sets::diacritic(), "Diacritic");
test_set(sets::emoji_modifier_base(), "Emoji_Modifier_Base");
test_set(sets::emoji_component(), "Emoji_Component");
test_set(sets::emoji_modifier(), "Emoji_Modifier");
test_set(sets::emoji(), "Emoji");
test_set(sets::emoji_presentation(), "Emoji_Presentation");
test_set(sets::extender(), "Extender");
test_set(sets::extended_pictographic(), "Extended_Pictographic");
test_set(sets::graph(), "Graph");
test_set(sets::grapheme_base(), "Grapheme_Base");
test_set(sets::grapheme_extend(), "Grapheme_Extend");
test_set(sets::grapheme_link(), "Grapheme_Link");
test_set(sets::hex_digit(), "Hex_Digit");
test_set(sets::hyphen(), "Hyphen");
test_set(sets::id_continue(), "Id_Continue");
test_set(sets::ideographic(), "Ideographic");
test_set(sets::id_start(), "Id_Start");
test_set(sets::ids_binary_operator(), "Ids_Binary_Operator");
test_set(sets::ids_trinary_operator(), "Ids_Trinary_Operator");
test_set(sets::join_control(), "Join_Control");
test_set(sets::logical_order_exception(), "Logical_Order_Exception");
test_set(sets::lowercase(), "Lowercase");
test_set(sets::math(), "Math");
test_set(sets::noncharacter_code_point(), "Noncharacter_Code_Point");
test_set(sets::nfc_inert(), "NFC_Inert");
test_set(sets::nfd_inert(), "NFD_Inert");
test_set(sets::nfkc_inert(), "NFKC_Inert");
test_set(sets::nfkd_inert(), "NFKD_Inert");
test_set(sets::pattern_syntax(), "Pattern_Syntax");
test_set(sets::pattern_white_space(), "Pattern_White_Space");
test_set(
sets::prepended_concatenation_mark(),
"Prepended_Concatenation_Mark",
);
test_set(sets::print(), "Print");
test_set(sets::quotation_mark(), "Quotation_Mark");
test_set(sets::radical(), "Radical");
test_set(sets::regional_indicator(), "Regional_Indicator");
test_set(sets::soft_dotted(), "Soft_Dotted");
test_set(sets::segment_starter(), "Segment_Starter");
test_set(sets::case_sensitive(), "Case_Sensitive");
test_set(sets::sentence_terminal(), "Sentence_Terminal");
test_set(sets::terminal_punctuation(), "Terminal_Punctuation");
test_set(sets::unified_ideograph(), "Unified_Ideograph");
test_set(sets::uppercase(), "Uppercase");
test_set(sets::variation_selector(), "Variation_Selector");
test_set(sets::white_space(), "White_Space");
test_set(sets::xdigit(), "Xdigit");
test_set(sets::xid_continue(), "XID_Continue");
test_set(sets::xid_start(), "XID_Start");
}
#[test]
fn test_complement_maps() {
let gc = maps::general_category();
let script = maps::script();
test_map(&gc, GeneralCategory::UppercaseLetter, "gc");
test_map(&gc, GeneralCategory::OtherPunctuation, "gc");
test_map(&script, Script::Devanagari, "script");
test_map(&script, Script::Latin, "script");
test_map(&script, Script::Common, "script");
}
}