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| pub trait Pattern<T: ?Sized>: Sized { | |
| type Searcher: Search<T>; | |
| fn into_searcher(self) -> Self::Searcher; | |
| fn search(self, haystack: &T) -> SearchSteps<'_, Self::Searcher, T> { | |
| self.into_searcher().search(haystack) | |
| } | |
| fn search_back(self, haystack: &T) -> SearchStepsBack<'_, Self::Searcher, T> | |
| where Self::Searcher: SearchBack<T> | |
| { | |
| self.into_searcher().search_back(haystack) | |
| } | |
| } | |
| // Safety requirements | |
| // | |
| // The safety requirements are determined by the type `T` | |
| // | |
| // For `str`: | |
| // - `start` and `end` of `SearchStep` returned by `step` | |
| // are both on a utf-8 code point boundary within haystack | |
| pub unsafe trait Search<T: ?Sized>: Sized { | |
| fn step(&mut self, haystack: &T) -> Option<SearchStep>; | |
| fn search(self, haystack: &T) -> SearchSteps<'_, Self, T> { | |
| SearchSteps { haystack, searcher: self } | |
| } | |
| } | |
| // Safety requirements | |
| // | |
| // The safety requirements are determined by the type `T` | |
| // | |
| // For `str`: | |
| // - `start` and `end` of `SearchStep` returned by `step_back` | |
| // are both on a utf-8 code point boundary within haystack | |
| pub unsafe trait SearchBack<T: ?Sized>: Search<T> { | |
| fn step_back(&mut self, haystack: &T) -> Option<SearchStep>; | |
| fn search_back(self, haystack: &T) -> SearchStepsBack<'_, Self, T> { | |
| SearchStepsBack { haystack, searcher: self } | |
| } | |
| } | |
| pub struct SearchStep { | |
| pub matches: bool, | |
| pub start: usize, | |
| pub end: usize, | |
| } | |
| pub struct SearchSteps<'a, S, T: ?Sized> { | |
| haystack: &'a T, | |
| searcher: S, | |
| } | |
| impl<'a, S: Search<T>, T: ?Sized> Iterator for SearchSteps<'a, S, T> { | |
| type Item = SearchStep; | |
| fn next(&mut self) -> Option<SearchStep> { | |
| self.searcher.step(self.haystack) | |
| } | |
| } | |
| pub struct SearchStepsBack<'a, S, T: ?Sized> { | |
| haystack: &'a T, | |
| searcher: S, | |
| } | |
| impl<'a, S: SearchBack<T>, T: ?Sized> Iterator for SearchStepsBack<'a, S, T> { | |
| type Item = SearchStep; | |
| fn next(&mut self) -> Option<SearchStep> { | |
| self.searcher.step_back(self.haystack) | |
| } | |
| } | |
| // For example: | |
| pub fn str_contains(s: &str, pat: impl Pattern<str>) -> bool { | |
| pat.search(s).any(|step| step.matches) | |
| } | |
| pub fn slice_contains<T>(s: &[T], pat: impl Pattern<[T]>) -> bool { | |
| pat.search(s).any(|step| step.matches) | |
| } |
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