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Diffstat (limited to 'vendor/bstr/src/unicode/sentence.rs')
-rw-r--r-- | vendor/bstr/src/unicode/sentence.rs | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/vendor/bstr/src/unicode/sentence.rs b/vendor/bstr/src/unicode/sentence.rs new file mode 100644 index 0000000..0baf4df --- /dev/null +++ b/vendor/bstr/src/unicode/sentence.rs @@ -0,0 +1,228 @@ +use regex_automata::{dfa::Automaton, Anchored, Input}; + +use crate::{ + ext_slice::ByteSlice, + unicode::fsm::sentence_break_fwd::SENTENCE_BREAK_FWD, utf8, +}; + +/// An iterator over sentences in a byte string. +/// +/// This iterator is typically constructed by +/// [`ByteSlice::sentences`](trait.ByteSlice.html#method.sentences). +/// +/// Sentences typically include their trailing punctuation and whitespace. +/// +/// Since sentences are made up of one or more codepoints, this iterator yields +/// `&str` elements. When invalid UTF-8 is encountered, replacement codepoints +/// are [substituted](index.html#handling-of-invalid-utf-8). +/// +/// This iterator yields words in accordance with the default sentence boundary +/// rules specified in +/// [UAX #29](https://www.unicode.org/reports/tr29/tr29-33.html#Sentence_Boundaries). +#[derive(Clone, Debug)] +pub struct Sentences<'a> { + bs: &'a [u8], +} + +impl<'a> Sentences<'a> { + pub(crate) fn new(bs: &'a [u8]) -> Sentences<'a> { + Sentences { bs } + } + + /// View the underlying data as a subslice of the original data. + /// + /// The slice returned has the same lifetime as the original slice, and so + /// the iterator can continue to be used while this exists. + /// + /// # Examples + /// + /// ``` + /// use bstr::ByteSlice; + /// + /// let mut it = b"I want this. Not that. Right now.".sentences(); + /// + /// assert_eq!(&b"I want this. Not that. Right now."[..], it.as_bytes()); + /// it.next(); + /// assert_eq!(b"Not that. Right now.", it.as_bytes()); + /// it.next(); + /// it.next(); + /// assert_eq!(b"", it.as_bytes()); + /// ``` + #[inline] + pub fn as_bytes(&self) -> &'a [u8] { + self.bs + } +} + +impl<'a> Iterator for Sentences<'a> { + type Item = &'a str; + + #[inline] + fn next(&mut self) -> Option<&'a str> { + let (sentence, size) = decode_sentence(self.bs); + if size == 0 { + return None; + } + self.bs = &self.bs[size..]; + Some(sentence) + } +} + +/// An iterator over sentences in a byte string, along with their byte offsets. +/// +/// This iterator is typically constructed by +/// [`ByteSlice::sentence_indices`](trait.ByteSlice.html#method.sentence_indices). +/// +/// Sentences typically include their trailing punctuation and whitespace. +/// +/// Since sentences are made up of one or more codepoints, this iterator +/// yields `&str` elements (along with their start and end byte offsets). +/// When invalid UTF-8 is encountered, replacement codepoints are +/// [substituted](index.html#handling-of-invalid-utf-8). Because of this, the +/// indices yielded by this iterator may not correspond to the length of the +/// sentence yielded with those indices. For example, when this iterator +/// encounters `\xFF` in the byte string, then it will yield a pair of indices +/// ranging over a single byte, but will provide an `&str` equivalent to +/// `"\u{FFFD}"`, which is three bytes in length. However, when given only +/// valid UTF-8, then all indices are in exact correspondence with their paired +/// word. +/// +/// This iterator yields words in accordance with the default sentence boundary +/// rules specified in +/// [UAX #29](https://www.unicode.org/reports/tr29/tr29-33.html#Sentence_Boundaries). +#[derive(Clone, Debug)] +pub struct SentenceIndices<'a> { + bs: &'a [u8], + forward_index: usize, +} + +impl<'a> SentenceIndices<'a> { + pub(crate) fn new(bs: &'a [u8]) -> SentenceIndices<'a> { + SentenceIndices { bs, forward_index: 0 } + } + + /// View the underlying data as a subslice of the original data. + /// + /// The slice returned has the same lifetime as the original slice, and so + /// the iterator can continue to be used while this exists. + /// + /// # Examples + /// + /// ``` + /// use bstr::ByteSlice; + /// + /// let mut it = b"I want this. Not that. Right now.".sentence_indices(); + /// + /// assert_eq!(&b"I want this. Not that. Right now."[..], it.as_bytes()); + /// it.next(); + /// assert_eq!(b"Not that. Right now.", it.as_bytes()); + /// it.next(); + /// it.next(); + /// assert_eq!(b"", it.as_bytes()); + /// ``` + #[inline] + pub fn as_bytes(&self) -> &'a [u8] { + self.bs + } +} + +impl<'a> Iterator for SentenceIndices<'a> { + type Item = (usize, usize, &'a str); + + #[inline] + fn next(&mut self) -> Option<(usize, usize, &'a str)> { + let index = self.forward_index; + let (word, size) = decode_sentence(self.bs); + if size == 0 { + return None; + } + self.bs = &self.bs[size..]; + self.forward_index += size; + Some((index, index + size, word)) + } +} + +fn decode_sentence(bs: &[u8]) -> (&str, usize) { + if bs.is_empty() { + ("", 0) + } else if let Some(hm) = { + let input = Input::new(bs).anchored(Anchored::Yes); + SENTENCE_BREAK_FWD.try_search_fwd(&input).unwrap() + } { + // Safe because a match can only occur for valid UTF-8. + let sentence = unsafe { bs[..hm.offset()].to_str_unchecked() }; + (sentence, sentence.len()) + } else { + const INVALID: &'static str = "\u{FFFD}"; + // No match on non-empty bytes implies we found invalid UTF-8. + let (_, size) = utf8::decode_lossy(bs); + (INVALID, size) + } +} + +#[cfg(all(test, feature = "std"))] +mod tests { + #[cfg(not(miri))] + use ucd_parse::SentenceBreakTest; + + use crate::ext_slice::ByteSlice; + + #[test] + #[cfg(not(miri))] + fn forward_ucd() { + for (i, test) in ucdtests().into_iter().enumerate() { + let given = test.sentences.concat(); + let got = sentences(given.as_bytes()); + assert_eq!( + test.sentences, + got, + "\n\nsentence forward break test {} failed:\n\ + given: {:?}\n\ + expected: {:?}\n\ + got: {:?}\n", + i, + given, + strs_to_bstrs(&test.sentences), + strs_to_bstrs(&got), + ); + } + } + + // Some additional tests that don't seem to be covered by the UCD tests. + #[test] + fn forward_additional() { + assert_eq!(vec!["a.. ", "A"], sentences(b"a.. A")); + assert_eq!(vec!["a.. a"], sentences(b"a.. a")); + + assert_eq!(vec!["a... ", "A"], sentences(b"a... A")); + assert_eq!(vec!["a... a"], sentences(b"a... a")); + + assert_eq!(vec!["a...,..., a"], sentences(b"a...,..., a")); + } + + fn sentences(bytes: &[u8]) -> Vec<&str> { + bytes.sentences().collect() + } + + #[cfg(not(miri))] + fn strs_to_bstrs<S: AsRef<str>>(strs: &[S]) -> Vec<&[u8]> { + strs.iter().map(|s| s.as_ref().as_bytes()).collect() + } + + /// Return all of the UCD for sentence breaks. + #[cfg(not(miri))] + fn ucdtests() -> Vec<SentenceBreakTest> { + const TESTDATA: &'static str = + include_str!("data/SentenceBreakTest.txt"); + + let mut tests = vec![]; + for mut line in TESTDATA.lines() { + line = line.trim(); + if line.starts_with("#") || line.contains("surrogate") { + continue; + } + tests.push(line.parse().unwrap()); + } + tests + } +} |