| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/regex-syntax-0.7.2/src/hir/interval.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>interval.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../regex_syntax/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../regex_syntax/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| <span id="540">540</span> |
| <span id="541">541</span> |
| <span id="542">542</span> |
| <span id="543">543</span> |
| <span id="544">544</span> |
| <span id="545">545</span> |
| <span id="546">546</span> |
| <span id="547">547</span> |
| <span id="548">548</span> |
| <span id="549">549</span> |
| <span id="550">550</span> |
| <span id="551">551</span> |
| <span id="552">552</span> |
| <span id="553">553</span> |
| <span id="554">554</span> |
| <span id="555">555</span> |
| <span id="556">556</span> |
| <span id="557">557</span> |
| <span id="558">558</span> |
| <span id="559">559</span> |
| <span id="560">560</span> |
| <span id="561">561</span> |
| <span id="562">562</span> |
| <span id="563">563</span> |
| <span id="564">564</span> |
| <span id="565">565</span> |
| <span id="566">566</span> |
| <span id="567">567</span> |
| <span id="568">568</span> |
| <span id="569">569</span> |
| <span id="570">570</span> |
| <span id="571">571</span> |
| <span id="572">572</span> |
| <span id="573">573</span> |
| <span id="574">574</span> |
| <span id="575">575</span> |
| <span id="576">576</span> |
| <span id="577">577</span> |
| <span id="578">578</span> |
| <span id="579">579</span> |
| <span id="580">580</span> |
| <span id="581">581</span> |
| </pre><pre class="rust"><code><span class="kw">use </span>core::{char, cmp, fmt::Debug, slice}; |
| |
| <span class="kw">use </span>alloc::vec::Vec; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::unicode; |
| |
| <span class="comment">// This module contains an *internal* implementation of interval sets. |
| // |
| // The primary invariant that interval sets guards is canonical ordering. That |
| // is, every interval set contains an ordered sequence of intervals where |
| // no two intervals are overlapping or adjacent. While this invariant is |
| // occasionally broken within the implementation, it should be impossible for |
| // callers to observe it. |
| // |
| // Since case folding (as implemented below) breaks that invariant, we roll |
| // that into this API even though it is a little out of place in an otherwise |
| // generic interval set. (Hence the reason why the `unicode` module is imported |
| // here.) |
| // |
| // Some of the implementation complexity here is a result of me wanting to |
| // preserve the sequential representation without using additional memory. |
| // In many cases, we do use linear extra memory, but it is at most 2x and it |
| // is amortized. If we relaxed the memory requirements, this implementation |
| // could become much simpler. The extra memory is honestly probably OK, but |
| // character classes (especially of the Unicode variety) can become quite |
| // large, and it would be nice to keep regex compilation snappy even in debug |
| // builds. (In the past, I have been careless with this area of code and it has |
| // caused slow regex compilations in debug mode, so this isn't entirely |
| // unwarranted.) |
| // |
| // Tests on this are relegated to the public API of HIR in src/hir.rs. |
| |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>IntervalSet<I> { |
| <span class="doccomment">/// A sorted set of non-overlapping ranges. |
| </span>ranges: Vec<I>, |
| <span class="doccomment">/// While not required at all for correctness, we keep track of whether an |
| /// interval set has been case folded or not. This helps us avoid doing |
| /// redundant work if, for example, a set has already been cased folded. |
| /// And note that whether a set is folded or not is preserved through |
| /// all of the pairwise set operations. That is, if both interval sets |
| /// have been case folded, then any of difference, union, intersection or |
| /// symmetric difference all produce a case folded set. |
| /// |
| /// Note that when this is true, it *must* be the case that the set is case |
| /// folded. But when it's false, the set *may* be case folded. In other |
| /// words, we only set this to true when we know it to be case, but we're |
| /// okay with it being false if it would otherwise be costly to determine |
| /// whether it should be true. This means code cannot assume that a false |
| /// value necessarily indicates that the set is not case folded. |
| /// |
| /// Bottom line: this is a performance optimization. |
| </span>folded: bool, |
| } |
| |
| <span class="kw">impl</span><I: Interval> Eq <span class="kw">for </span>IntervalSet<I> {} |
| |
| <span class="comment">// We implement PartialEq manually so that we don't consider the set's internal |
| // 'folded' property to be part of its identity. The 'folded' property is |
| // strictly an optimization. |
| </span><span class="kw">impl</span><I: Interval> PartialEq <span class="kw">for </span>IntervalSet<I> { |
| <span class="kw">fn </span>eq(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span>IntervalSet<I>) -> bool { |
| <span class="self">self</span>.ranges.eq(<span class="kw-2">&</span>other.ranges) |
| } |
| } |
| |
| <span class="kw">impl</span><I: Interval> IntervalSet<I> { |
| <span class="doccomment">/// Create a new set from a sequence of intervals. Each interval is |
| /// specified as a pair of bounds, where both bounds are inclusive. |
| /// |
| /// The given ranges do not need to be in any specific order, and ranges |
| /// may overlap. |
| </span><span class="kw">pub fn </span>new<T: IntoIterator<Item = I>>(intervals: T) -> IntervalSet<I> { |
| <span class="kw">let </span>ranges: Vec<I> = intervals.into_iter().collect(); |
| <span class="comment">// An empty set is case folded. |
| </span><span class="kw">let </span>folded = ranges.is_empty(); |
| <span class="kw">let </span><span class="kw-2">mut </span>set = IntervalSet { ranges, folded }; |
| set.canonicalize(); |
| set |
| } |
| |
| <span class="doccomment">/// Add a new interval to this set. |
| </span><span class="kw">pub fn </span>push(<span class="kw-2">&mut </span><span class="self">self</span>, interval: I) { |
| <span class="comment">// TODO: This could be faster. e.g., Push the interval such that |
| // it preserves canonicalization. |
| </span><span class="self">self</span>.ranges.push(interval); |
| <span class="self">self</span>.canonicalize(); |
| <span class="comment">// We don't know whether the new interval added here is considered |
| // case folded, so we conservatively assume that the entire set is |
| // no longer case folded if it was previously. |
| </span><span class="self">self</span>.folded = <span class="bool-val">false</span>; |
| } |
| |
| <span class="doccomment">/// Return an iterator over all intervals in this set. |
| /// |
| /// The iterator yields intervals in ascending order. |
| </span><span class="kw">pub fn </span>iter(<span class="kw-2">&</span><span class="self">self</span>) -> IntervalSetIter<<span class="lifetime">'_</span>, I> { |
| IntervalSetIter(<span class="self">self</span>.ranges.iter()) |
| } |
| |
| <span class="doccomment">/// Return an immutable slice of intervals in this set. |
| /// |
| /// The sequence returned is in canonical ordering. |
| </span><span class="kw">pub fn </span>intervals(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>[I] { |
| <span class="kw-2">&</span><span class="self">self</span>.ranges |
| } |
| |
| <span class="doccomment">/// Expand this interval set such that it contains all case folded |
| /// characters. For example, if this class consists of the range `a-z`, |
| /// then applying case folding will result in the class containing both the |
| /// ranges `a-z` and `A-Z`. |
| /// |
| /// This returns an error if the necessary case mapping data is not |
| /// available. |
| </span><span class="kw">pub fn </span>case_fold_simple(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><(), unicode::CaseFoldError> { |
| <span class="kw">if </span><span class="self">self</span>.folded { |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| <span class="kw">let </span>len = <span class="self">self</span>.ranges.len(); |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..len { |
| <span class="kw">let </span>range = <span class="self">self</span>.ranges[i]; |
| <span class="kw">if let </span><span class="prelude-val">Err</span>(err) = range.case_fold_simple(<span class="kw-2">&mut </span><span class="self">self</span>.ranges) { |
| <span class="self">self</span>.canonicalize(); |
| <span class="kw">return </span><span class="prelude-val">Err</span>(err); |
| } |
| } |
| <span class="self">self</span>.canonicalize(); |
| <span class="self">self</span>.folded = <span class="bool-val">true</span>; |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="doccomment">/// Union this set with the given set, in place. |
| </span><span class="kw">pub fn </span>union(<span class="kw-2">&mut </span><span class="self">self</span>, other: <span class="kw-2">&</span>IntervalSet<I>) { |
| <span class="kw">if </span>other.ranges.is_empty() || <span class="self">self</span>.ranges == other.ranges { |
| <span class="kw">return</span>; |
| } |
| <span class="comment">// This could almost certainly be done more efficiently. |
| </span><span class="self">self</span>.ranges.extend(<span class="kw-2">&</span>other.ranges); |
| <span class="self">self</span>.canonicalize(); |
| <span class="self">self</span>.folded = <span class="self">self</span>.folded && other.folded; |
| } |
| |
| <span class="doccomment">/// Intersect this set with the given set, in place. |
| </span><span class="kw">pub fn </span>intersect(<span class="kw-2">&mut </span><span class="self">self</span>, other: <span class="kw-2">&</span>IntervalSet<I>) { |
| <span class="kw">if </span><span class="self">self</span>.ranges.is_empty() { |
| <span class="kw">return</span>; |
| } |
| <span class="kw">if </span>other.ranges.is_empty() { |
| <span class="self">self</span>.ranges.clear(); |
| <span class="comment">// An empty set is case folded. |
| </span><span class="self">self</span>.folded = <span class="bool-val">true</span>; |
| <span class="kw">return</span>; |
| } |
| |
| <span class="comment">// There should be a way to do this in-place with constant memory, |
| // but I couldn't figure out a simple way to do it. So just append |
| // the intersection to the end of this range, and then drain it before |
| // we're done. |
| </span><span class="kw">let </span>drain_end = <span class="self">self</span>.ranges.len(); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>ita = <span class="number">0</span>..drain_end; |
| <span class="kw">let </span><span class="kw-2">mut </span>itb = <span class="number">0</span>..other.ranges.len(); |
| <span class="kw">let </span><span class="kw-2">mut </span>a = ita.next().unwrap(); |
| <span class="kw">let </span><span class="kw-2">mut </span>b = itb.next().unwrap(); |
| <span class="kw">loop </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(ab) = <span class="self">self</span>.ranges[a].intersect(<span class="kw-2">&</span>other.ranges[b]) { |
| <span class="self">self</span>.ranges.push(ab); |
| } |
| <span class="kw">let </span>(it, aorb) = |
| <span class="kw">if </span><span class="self">self</span>.ranges[a].upper() < other.ranges[b].upper() { |
| (<span class="kw-2">&mut </span>ita, <span class="kw-2">&mut </span>a) |
| } <span class="kw">else </span>{ |
| (<span class="kw-2">&mut </span>itb, <span class="kw-2">&mut </span>b) |
| }; |
| <span class="kw">match </span>it.next() { |
| <span class="prelude-val">Some</span>(v) => <span class="kw-2">*</span>aorb = v, |
| <span class="prelude-val">None </span>=> <span class="kw">break</span>, |
| } |
| } |
| <span class="self">self</span>.ranges.drain(..drain_end); |
| <span class="self">self</span>.folded = <span class="self">self</span>.folded && other.folded; |
| } |
| |
| <span class="doccomment">/// Subtract the given set from this set, in place. |
| </span><span class="kw">pub fn </span>difference(<span class="kw-2">&mut </span><span class="self">self</span>, other: <span class="kw-2">&</span>IntervalSet<I>) { |
| <span class="kw">if </span><span class="self">self</span>.ranges.is_empty() || other.ranges.is_empty() { |
| <span class="kw">return</span>; |
| } |
| |
| <span class="comment">// This algorithm is (to me) surprisingly complex. A search of the |
| // interwebs indicate that this is a potentially interesting problem. |
| // Folks seem to suggest interval or segment trees, but I'd like to |
| // avoid the overhead (both runtime and conceptual) of that. |
| // |
| // The following is basically my Shitty First Draft. Therefore, in |
| // order to grok it, you probably need to read each line carefully. |
| // Simplifications are most welcome! |
| // |
| // Remember, we can assume the canonical format invariant here, which |
| // says that all ranges are sorted, not overlapping and not adjacent in |
| // each class. |
| </span><span class="kw">let </span>drain_end = <span class="self">self</span>.ranges.len(); |
| <span class="kw">let </span>(<span class="kw-2">mut </span>a, <span class="kw-2">mut </span>b) = (<span class="number">0</span>, <span class="number">0</span>); |
| <span class="lifetime">'LOOP</span>: <span class="kw">while </span>a < drain_end && b < other.ranges.len() { |
| <span class="comment">// Basically, the easy cases are when neither range overlaps with |
| // each other. If the `b` range is less than our current `a` |
| // range, then we can skip it and move on. |
| </span><span class="kw">if </span>other.ranges[b].upper() < <span class="self">self</span>.ranges[a].lower() { |
| b += <span class="number">1</span>; |
| <span class="kw">continue</span>; |
| } |
| <span class="comment">// ... similarly for the `a` range. If it's less than the smallest |
| // `b` range, then we can add it as-is. |
| </span><span class="kw">if </span><span class="self">self</span>.ranges[a].upper() < other.ranges[b].lower() { |
| <span class="kw">let </span>range = <span class="self">self</span>.ranges[a]; |
| <span class="self">self</span>.ranges.push(range); |
| a += <span class="number">1</span>; |
| <span class="kw">continue</span>; |
| } |
| <span class="comment">// Otherwise, we have overlapping ranges. |
| </span><span class="macro">assert!</span>(!<span class="self">self</span>.ranges[a].is_intersection_empty(<span class="kw-2">&</span>other.ranges[b])); |
| |
| <span class="comment">// This part is tricky and was non-obvious to me without looking |
| // at explicit examples (see the tests). The trickiness stems from |
| // two things: 1) subtracting a range from another range could |
| // yield two ranges and 2) after subtracting a range, it's possible |
| // that future ranges can have an impact. The loop below advances |
| // the `b` ranges until they can't possible impact the current |
| // range. |
| // |
| // For example, if our `a` range is `a-t` and our next three `b` |
| // ranges are `a-c`, `g-i`, `r-t` and `x-z`, then we need to apply |
| // subtraction three times before moving on to the next `a` range. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>range = <span class="self">self</span>.ranges[a]; |
| <span class="kw">while </span>b < other.ranges.len() |
| && !range.is_intersection_empty(<span class="kw-2">&</span>other.ranges[b]) |
| { |
| <span class="kw">let </span>old_range = range; |
| range = <span class="kw">match </span>range.difference(<span class="kw-2">&</span>other.ranges[b]) { |
| (<span class="prelude-val">None</span>, <span class="prelude-val">None</span>) => { |
| <span class="comment">// We lost the entire range, so move on to the next |
| // without adding this one. |
| </span>a += <span class="number">1</span>; |
| <span class="kw">continue </span><span class="lifetime">'LOOP</span>; |
| } |
| (<span class="prelude-val">Some</span>(range1), <span class="prelude-val">None</span>) | (<span class="prelude-val">None</span>, <span class="prelude-val">Some</span>(range1)) => range1, |
| (<span class="prelude-val">Some</span>(range1), <span class="prelude-val">Some</span>(range2)) => { |
| <span class="self">self</span>.ranges.push(range1); |
| range2 |
| } |
| }; |
| <span class="comment">// It's possible that the `b` range has more to contribute |
| // here. In particular, if it is greater than the original |
| // range, then it might impact the next `a` range *and* it |
| // has impacted the current `a` range as much as possible, |
| // so we can quit. We don't bump `b` so that the next `a` |
| // range can apply it. |
| </span><span class="kw">if </span>other.ranges[b].upper() > old_range.upper() { |
| <span class="kw">break</span>; |
| } |
| <span class="comment">// Otherwise, the next `b` range might apply to the current |
| // `a` range. |
| </span>b += <span class="number">1</span>; |
| } |
| <span class="self">self</span>.ranges.push(range); |
| a += <span class="number">1</span>; |
| } |
| <span class="kw">while </span>a < drain_end { |
| <span class="kw">let </span>range = <span class="self">self</span>.ranges[a]; |
| <span class="self">self</span>.ranges.push(range); |
| a += <span class="number">1</span>; |
| } |
| <span class="self">self</span>.ranges.drain(..drain_end); |
| <span class="self">self</span>.folded = <span class="self">self</span>.folded && other.folded; |
| } |
| |
| <span class="doccomment">/// Compute the symmetric difference of the two sets, in place. |
| /// |
| /// This computes the symmetric difference of two interval sets. This |
| /// removes all elements in this set that are also in the given set, |
| /// but also adds all elements from the given set that aren't in this |
| /// set. That is, the set will contain all elements in either set, |
| /// but will not contain any elements that are in both sets. |
| </span><span class="kw">pub fn </span>symmetric_difference(<span class="kw-2">&mut </span><span class="self">self</span>, other: <span class="kw-2">&</span>IntervalSet<I>) { |
| <span class="comment">// TODO(burntsushi): Fix this so that it amortizes allocation. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>intersection = <span class="self">self</span>.clone(); |
| intersection.intersect(other); |
| <span class="self">self</span>.union(other); |
| <span class="self">self</span>.difference(<span class="kw-2">&</span>intersection); |
| } |
| |
| <span class="doccomment">/// Negate this interval set. |
| /// |
| /// For all `x` where `x` is any element, if `x` was in this set, then it |
| /// will not be in this set after negation. |
| </span><span class="kw">pub fn </span>negate(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="kw">if </span><span class="self">self</span>.ranges.is_empty() { |
| <span class="kw">let </span>(min, max) = (I::Bound::min_value(), I::Bound::max_value()); |
| <span class="self">self</span>.ranges.push(I::create(min, max)); |
| <span class="comment">// The set containing everything must case folded. |
| </span><span class="self">self</span>.folded = <span class="bool-val">true</span>; |
| <span class="kw">return</span>; |
| } |
| |
| <span class="comment">// There should be a way to do this in-place with constant memory, |
| // but I couldn't figure out a simple way to do it. So just append |
| // the negation to the end of this range, and then drain it before |
| // we're done. |
| </span><span class="kw">let </span>drain_end = <span class="self">self</span>.ranges.len(); |
| |
| <span class="comment">// We do checked arithmetic below because of the canonical ordering |
| // invariant. |
| </span><span class="kw">if </span><span class="self">self</span>.ranges[<span class="number">0</span>].lower() > I::Bound::min_value() { |
| <span class="kw">let </span>upper = <span class="self">self</span>.ranges[<span class="number">0</span>].lower().decrement(); |
| <span class="self">self</span>.ranges.push(I::create(I::Bound::min_value(), upper)); |
| } |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">1</span>..drain_end { |
| <span class="kw">let </span>lower = <span class="self">self</span>.ranges[i - <span class="number">1</span>].upper().increment(); |
| <span class="kw">let </span>upper = <span class="self">self</span>.ranges[i].lower().decrement(); |
| <span class="self">self</span>.ranges.push(I::create(lower, upper)); |
| } |
| <span class="kw">if </span><span class="self">self</span>.ranges[drain_end - <span class="number">1</span>].upper() < I::Bound::max_value() { |
| <span class="kw">let </span>lower = <span class="self">self</span>.ranges[drain_end - <span class="number">1</span>].upper().increment(); |
| <span class="self">self</span>.ranges.push(I::create(lower, I::Bound::max_value())); |
| } |
| <span class="self">self</span>.ranges.drain(..drain_end); |
| <span class="comment">// We don't need to update whether this set is folded or not, because |
| // it is conservatively preserved through negation. Namely, if a set |
| // is not folded, then it is possible that its negation is folded, for |
| // example, [^☃]. But we're fine with assuming that the set is not |
| // folded in that case. (`folded` permits false negatives but not false |
| // positives.) |
| // |
| // But what about when a set is folded, is its negation also |
| // necessarily folded? Yes. Because if a set is folded, then for every |
| // character in the set, it necessarily included its equivalence class |
| // of case folded characters. Negating it in turn means that all |
| // equivalence classes in the set are negated, and any equivalence |
| // class that was previously not in the set is now entirely in the set. |
| </span>} |
| |
| <span class="doccomment">/// Converts this set into a canonical ordering. |
| </span><span class="kw">fn </span>canonicalize(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="kw">if </span><span class="self">self</span>.is_canonical() { |
| <span class="kw">return</span>; |
| } |
| <span class="self">self</span>.ranges.sort(); |
| <span class="macro">assert!</span>(!<span class="self">self</span>.ranges.is_empty()); |
| |
| <span class="comment">// Is there a way to do this in-place with constant memory? I couldn't |
| // figure out a way to do it. So just append the canonicalization to |
| // the end of this range, and then drain it before we're done. |
| </span><span class="kw">let </span>drain_end = <span class="self">self</span>.ranges.len(); |
| <span class="kw">for </span>oldi <span class="kw">in </span><span class="number">0</span>..drain_end { |
| <span class="comment">// If we've added at least one new range, then check if we can |
| // merge this range in the previously added range. |
| </span><span class="kw">if </span><span class="self">self</span>.ranges.len() > drain_end { |
| <span class="kw">let </span>(last, rest) = <span class="self">self</span>.ranges.split_last_mut().unwrap(); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(union) = last.union(<span class="kw-2">&</span>rest[oldi]) { |
| <span class="kw-2">*</span>last = union; |
| <span class="kw">continue</span>; |
| } |
| } |
| <span class="kw">let </span>range = <span class="self">self</span>.ranges[oldi]; |
| <span class="self">self</span>.ranges.push(range); |
| } |
| <span class="self">self</span>.ranges.drain(..drain_end); |
| } |
| |
| <span class="doccomment">/// Returns true if and only if this class is in a canonical ordering. |
| </span><span class="kw">fn </span>is_canonical(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="kw">for </span>pair <span class="kw">in </span><span class="self">self</span>.ranges.windows(<span class="number">2</span>) { |
| <span class="kw">if </span>pair[<span class="number">0</span>] >= pair[<span class="number">1</span>] { |
| <span class="kw">return </span><span class="bool-val">false</span>; |
| } |
| <span class="kw">if </span>pair[<span class="number">0</span>].is_contiguous(<span class="kw-2">&</span>pair[<span class="number">1</span>]) { |
| <span class="kw">return </span><span class="bool-val">false</span>; |
| } |
| } |
| <span class="bool-val">true |
| </span>} |
| } |
| |
| <span class="doccomment">/// An iterator over intervals. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>IntervalSetIter<<span class="lifetime">'a</span>, I>(slice::Iter<<span class="lifetime">'a</span>, I>); |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, I> Iterator <span class="kw">for </span>IntervalSetIter<<span class="lifetime">'a</span>, I> { |
| <span class="kw">type </span>Item = <span class="kw-2">&</span><span class="lifetime">'a </span>I; |
| |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'a </span>I> { |
| <span class="self">self</span>.<span class="number">0</span>.next() |
| } |
| } |
| |
| <span class="kw">pub trait </span>Interval: |
| Clone + Copy + Debug + Default + Eq + PartialEq + PartialOrd + Ord |
| { |
| <span class="kw">type </span>Bound: Bound; |
| |
| <span class="kw">fn </span>lower(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Bound; |
| <span class="kw">fn </span>upper(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Bound; |
| <span class="kw">fn </span>set_lower(<span class="kw-2">&mut </span><span class="self">self</span>, bound: <span class="self">Self</span>::Bound); |
| <span class="kw">fn </span>set_upper(<span class="kw-2">&mut </span><span class="self">self</span>, bound: <span class="self">Self</span>::Bound); |
| <span class="kw">fn </span>case_fold_simple( |
| <span class="kw-2">&</span><span class="self">self</span>, |
| intervals: <span class="kw-2">&mut </span>Vec<<span class="self">Self</span>>, |
| ) -> <span class="prelude-ty">Result</span><(), unicode::CaseFoldError>; |
| |
| <span class="doccomment">/// Create a new interval. |
| </span><span class="kw">fn </span>create(lower: <span class="self">Self</span>::Bound, upper: <span class="self">Self</span>::Bound) -> <span class="self">Self </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>int = <span class="self">Self</span>::default(); |
| <span class="kw">if </span>lower <= upper { |
| int.set_lower(lower); |
| int.set_upper(upper); |
| } <span class="kw">else </span>{ |
| int.set_lower(upper); |
| int.set_upper(lower); |
| } |
| int |
| } |
| |
| <span class="doccomment">/// Union the given overlapping range into this range. |
| /// |
| /// If the two ranges aren't contiguous, then this returns `None`. |
| </span><span class="kw">fn </span>union(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>> { |
| <span class="kw">if </span>!<span class="self">self</span>.is_contiguous(other) { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">let </span>lower = cmp::min(<span class="self">self</span>.lower(), other.lower()); |
| <span class="kw">let </span>upper = cmp::max(<span class="self">self</span>.upper(), other.upper()); |
| <span class="prelude-val">Some</span>(<span class="self">Self</span>::create(lower, upper)) |
| } |
| |
| <span class="doccomment">/// Intersect this range with the given range and return the result. |
| /// |
| /// If the intersection is empty, then this returns `None`. |
| </span><span class="kw">fn </span>intersect(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>> { |
| <span class="kw">let </span>lower = cmp::max(<span class="self">self</span>.lower(), other.lower()); |
| <span class="kw">let </span>upper = cmp::min(<span class="self">self</span>.upper(), other.upper()); |
| <span class="kw">if </span>lower <= upper { |
| <span class="prelude-val">Some</span>(<span class="self">Self</span>::create(lower, upper)) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">None |
| </span>} |
| } |
| |
| <span class="doccomment">/// Subtract the given range from this range and return the resulting |
| /// ranges. |
| /// |
| /// If subtraction would result in an empty range, then no ranges are |
| /// returned. |
| </span><span class="kw">fn </span>difference(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> (<span class="prelude-ty">Option</span><<span class="self">Self</span>>, <span class="prelude-ty">Option</span><<span class="self">Self</span>>) { |
| <span class="kw">if </span><span class="self">self</span>.is_subset(other) { |
| <span class="kw">return </span>(<span class="prelude-val">None</span>, <span class="prelude-val">None</span>); |
| } |
| <span class="kw">if </span><span class="self">self</span>.is_intersection_empty(other) { |
| <span class="kw">return </span>(<span class="prelude-val">Some</span>(<span class="self">self</span>.clone()), <span class="prelude-val">None</span>); |
| } |
| <span class="kw">let </span>add_lower = other.lower() > <span class="self">self</span>.lower(); |
| <span class="kw">let </span>add_upper = other.upper() < <span class="self">self</span>.upper(); |
| <span class="comment">// We know this because !self.is_subset(other) and the ranges have |
| // a non-empty intersection. |
| </span><span class="macro">assert!</span>(add_lower || add_upper); |
| <span class="kw">let </span><span class="kw-2">mut </span>ret = (<span class="prelude-val">None</span>, <span class="prelude-val">None</span>); |
| <span class="kw">if </span>add_lower { |
| <span class="kw">let </span>upper = other.lower().decrement(); |
| ret.<span class="number">0 </span>= <span class="prelude-val">Some</span>(<span class="self">Self</span>::create(<span class="self">self</span>.lower(), upper)); |
| } |
| <span class="kw">if </span>add_upper { |
| <span class="kw">let </span>lower = other.upper().increment(); |
| <span class="kw">let </span>range = <span class="self">Self</span>::create(lower, <span class="self">self</span>.upper()); |
| <span class="kw">if </span>ret.<span class="number">0</span>.is_none() { |
| ret.<span class="number">0 </span>= <span class="prelude-val">Some</span>(range); |
| } <span class="kw">else </span>{ |
| ret.<span class="number">1 </span>= <span class="prelude-val">Some</span>(range); |
| } |
| } |
| ret |
| } |
| |
| <span class="doccomment">/// Compute the symmetric difference the given range from this range. This |
| /// returns the union of the two ranges minus its intersection. |
| </span><span class="kw">fn </span>symmetric_difference( |
| <span class="kw-2">&</span><span class="self">self</span>, |
| other: <span class="kw-2">&</span><span class="self">Self</span>, |
| ) -> (<span class="prelude-ty">Option</span><<span class="self">Self</span>>, <span class="prelude-ty">Option</span><<span class="self">Self</span>>) { |
| <span class="kw">let </span>union = <span class="kw">match </span><span class="self">self</span>.union(other) { |
| <span class="prelude-val">None </span>=> <span class="kw">return </span>(<span class="prelude-val">Some</span>(<span class="self">self</span>.clone()), <span class="prelude-val">Some</span>(other.clone())), |
| <span class="prelude-val">Some</span>(union) => union, |
| }; |
| <span class="kw">let </span>intersection = <span class="kw">match </span><span class="self">self</span>.intersect(other) { |
| <span class="prelude-val">None </span>=> <span class="kw">return </span>(<span class="prelude-val">Some</span>(<span class="self">self</span>.clone()), <span class="prelude-val">Some</span>(other.clone())), |
| <span class="prelude-val">Some</span>(intersection) => intersection, |
| }; |
| union.difference(<span class="kw-2">&</span>intersection) |
| } |
| |
| <span class="doccomment">/// Returns true if and only if the two ranges are contiguous. Two ranges |
| /// are contiguous if and only if the ranges are either overlapping or |
| /// adjacent. |
| </span><span class="kw">fn </span>is_contiguous(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> bool { |
| <span class="kw">let </span>lower1 = <span class="self">self</span>.lower().as_u32(); |
| <span class="kw">let </span>upper1 = <span class="self">self</span>.upper().as_u32(); |
| <span class="kw">let </span>lower2 = other.lower().as_u32(); |
| <span class="kw">let </span>upper2 = other.upper().as_u32(); |
| cmp::max(lower1, lower2) <= cmp::min(upper1, upper2).saturating_add(<span class="number">1</span>) |
| } |
| |
| <span class="doccomment">/// Returns true if and only if the intersection of this range and the |
| /// other range is empty. |
| </span><span class="kw">fn </span>is_intersection_empty(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> bool { |
| <span class="kw">let </span>(lower1, upper1) = (<span class="self">self</span>.lower(), <span class="self">self</span>.upper()); |
| <span class="kw">let </span>(lower2, upper2) = (other.lower(), other.upper()); |
| cmp::max(lower1, lower2) > cmp::min(upper1, upper2) |
| } |
| |
| <span class="doccomment">/// Returns true if and only if this range is a subset of the other range. |
| </span><span class="kw">fn </span>is_subset(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> bool { |
| <span class="kw">let </span>(lower1, upper1) = (<span class="self">self</span>.lower(), <span class="self">self</span>.upper()); |
| <span class="kw">let </span>(lower2, upper2) = (other.lower(), other.upper()); |
| (lower2 <= lower1 && lower1 <= upper2) |
| && (lower2 <= upper1 && upper1 <= upper2) |
| } |
| } |
| |
| <span class="kw">pub trait </span>Bound: |
| Copy + Clone + Debug + Eq + PartialEq + PartialOrd + Ord |
| { |
| <span class="kw">fn </span>min_value() -> <span class="self">Self</span>; |
| <span class="kw">fn </span>max_value() -> <span class="self">Self</span>; |
| <span class="kw">fn </span>as_u32(<span class="self">self</span>) -> u32; |
| <span class="kw">fn </span>increment(<span class="self">self</span>) -> <span class="self">Self</span>; |
| <span class="kw">fn </span>decrement(<span class="self">self</span>) -> <span class="self">Self</span>; |
| } |
| |
| <span class="kw">impl </span>Bound <span class="kw">for </span>u8 { |
| <span class="kw">fn </span>min_value() -> <span class="self">Self </span>{ |
| u8::MIN |
| } |
| <span class="kw">fn </span>max_value() -> <span class="self">Self </span>{ |
| u8::MAX |
| } |
| <span class="kw">fn </span>as_u32(<span class="self">self</span>) -> u32 { |
| u32::from(<span class="self">self</span>) |
| } |
| <span class="kw">fn </span>increment(<span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="self">self</span>.checked_add(<span class="number">1</span>).unwrap() |
| } |
| <span class="kw">fn </span>decrement(<span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="self">self</span>.checked_sub(<span class="number">1</span>).unwrap() |
| } |
| } |
| |
| <span class="kw">impl </span>Bound <span class="kw">for </span>char { |
| <span class="kw">fn </span>min_value() -> <span class="self">Self </span>{ |
| <span class="string">'\x00' |
| </span>} |
| <span class="kw">fn </span>max_value() -> <span class="self">Self </span>{ |
| <span class="string">'\u{10FFFF}' |
| </span>} |
| <span class="kw">fn </span>as_u32(<span class="self">self</span>) -> u32 { |
| u32::from(<span class="self">self</span>) |
| } |
| |
| <span class="kw">fn </span>increment(<span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="kw">match </span><span class="self">self </span>{ |
| <span class="string">'\u{D7FF}' </span>=> <span class="string">'\u{E000}'</span>, |
| c => char::from_u32(u32::from(c).checked_add(<span class="number">1</span>).unwrap()).unwrap(), |
| } |
| } |
| |
| <span class="kw">fn </span>decrement(<span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="kw">match </span><span class="self">self </span>{ |
| <span class="string">'\u{E000}' </span>=> <span class="string">'\u{D7FF}'</span>, |
| c => char::from_u32(u32::from(c).checked_sub(<span class="number">1</span>).unwrap()).unwrap(), |
| } |
| } |
| } |
| |
| <span class="comment">// Tests for interval sets are written in src/hir.rs against the public API. |
| </span></code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="regex_syntax" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |