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https://gitee.com/openharmony/third_party_rust_regex
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ab72269b23
In other words, `\b` in a `bytes::Regex` can now be used in the DFA. This leads to a big performance boost: ``` sherlock::word_ending_n 115,465,261 (5 MB/s) 3,038,621 (195 MB/s) -112,426,640 -97.37% ``` Unfortunately, Unicode word boundaries continue to elude the DFA. This state of affairs is lamentable, but after a lot of thought, I've concluded there are only two ways to speed up Unicode word boundaries: 1. Come up with a hairbrained scheme to add multi-byte look-behind/ahead to the lazy DFA. (The theory says it's possible. Figuring out how to do this without combinatorial state explosion is not within my grasp at the moment.) 2. Build a second lazy DFA with transitions on Unicode codepoints instead of bytes. (The looming inevitability of this makes me queasy for a number of reasons.) To ameliorate this state of affairs, it is now possible to disable Unicode support in `Regex::new` with `(?-u)`. In other words, one can now use an ASCII word boundary with `(?-u:\b)`. Disabling Unicode support does not violate any invariants around UTF-8. In particular, if the regular expression could lead to a match of invalid UTF-8, then the parser will return an error. (This only happens for `Regex::new`. `bytes::Regex::new` still of course allows matching arbitrary bytes.) Finally, a new `PERFORMANCE.md` guide was written.
59 lines
1.2 KiB
Rust
59 lines
1.2 KiB
Rust
// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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extern crate rand;
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extern crate regex;
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macro_rules! regex_new {
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($re:expr) => {{
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use regex::bytes::Regex;
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Regex::new($re)
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}}
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}
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macro_rules! regex_set_new {
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($res:expr) => {{
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use regex::bytes::RegexSet;
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RegexSet::new($res)
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}}
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}
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macro_rules! regex {
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($re:expr) => {
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regex_new!($re).unwrap()
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}
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}
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macro_rules! regex_set {
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($res:expr) => {
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regex_set_new!($res).unwrap()
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}
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}
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// Must come before other module definitions.
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include!("macros_bytes.rs");
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include!("macros.rs");
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mod api;
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mod bytes;
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mod crazy;
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mod flags;
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mod fowler;
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mod multiline;
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mod noparse;
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mod regression;
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mod replace;
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mod set;
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mod shortest_match;
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mod suffix_reverse;
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mod unicode;
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mod word_boundary;
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mod word_boundary_ascii;
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