Import 'regex' package vesion 1.3.6
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Bug: 152884384
Test: make
Change-Id: I455caf7833b6c437c1c133bc7b2f47b83da9cbce
diff --git a/examples/shootout-regex-dna-cheat.rs b/examples/shootout-regex-dna-cheat.rs
new file mode 100644
index 0000000..27c5308
--- /dev/null
+++ b/examples/shootout-regex-dna-cheat.rs
@@ -0,0 +1,92 @@
+// The Computer Language Benchmarks Game
+// http://benchmarksgame.alioth.debian.org/
+//
+// contributed by the Rust Project Developers
+// contributed by TeXitoi
+// contributed by BurntSushi
+
+// This technically solves the problem posed in the `regex-dna` benchmark, but
+// it cheats by combining all of the replacements into a single regex and
+// replacing them with a single linear scan. i.e., it re-implements
+// `replace_all`. As a result, this is around 25% faster. ---AG
+
+extern crate regex;
+
+use std::io::{self, Read};
+use std::sync::Arc;
+use std::thread;
+
+macro_rules! regex {
+ ($re:expr) => {
+ ::regex::Regex::new($re).unwrap()
+ };
+}
+
+fn main() {
+ let mut seq = String::with_capacity(50 * (1 << 20));
+ io::stdin().read_to_string(&mut seq).unwrap();
+ let ilen = seq.len();
+
+ seq = regex!(">[^\n]*\n|\n").replace_all(&seq, "").into_owned();
+ let clen = seq.len();
+ let seq_arc = Arc::new(seq.clone());
+
+ let variants = vec![
+ regex!("agggtaaa|tttaccct"),
+ regex!("[cgt]gggtaaa|tttaccc[acg]"),
+ regex!("a[act]ggtaaa|tttacc[agt]t"),
+ regex!("ag[act]gtaaa|tttac[agt]ct"),
+ regex!("agg[act]taaa|ttta[agt]cct"),
+ regex!("aggg[acg]aaa|ttt[cgt]ccct"),
+ regex!("agggt[cgt]aa|tt[acg]accct"),
+ regex!("agggta[cgt]a|t[acg]taccct"),
+ regex!("agggtaa[cgt]|[acg]ttaccct"),
+ ];
+ let mut counts = vec![];
+ for variant in variants {
+ let seq = seq_arc.clone();
+ let restr = variant.to_string();
+ let future = thread::spawn(move || variant.find_iter(&seq).count());
+ counts.push((restr, future));
+ }
+
+ let substs = vec![
+ (b'B', "(c|g|t)"),
+ (b'D', "(a|g|t)"),
+ (b'H', "(a|c|t)"),
+ (b'K', "(g|t)"),
+ (b'M', "(a|c)"),
+ (b'N', "(a|c|g|t)"),
+ (b'R', "(a|g)"),
+ (b'S', "(c|g)"),
+ (b'V', "(a|c|g)"),
+ (b'W', "(a|t)"),
+ (b'Y', "(c|t)"),
+ ]; // combined into one regex in `replace_all`
+ let seq = replace_all(&seq, substs);
+
+ for (variant, count) in counts {
+ println!("{} {}", variant, count.join().unwrap());
+ }
+ println!("\n{}\n{}\n{}", ilen, clen, seq.len());
+}
+
+fn replace_all(text: &str, substs: Vec<(u8, &str)>) -> String {
+ let mut replacements = vec![""; 256];
+ let mut alternates = vec![];
+ for (re, replacement) in substs {
+ replacements[re as usize] = replacement;
+ alternates.push((re as char).to_string());
+ }
+
+ let re = regex!(&alternates.join("|"));
+ let mut new = String::with_capacity(text.len());
+ let mut last_match = 0;
+ for m in re.find_iter(text) {
+ new.push_str(&text[last_match..m.start()]);
+ new.push_str(replacements[text.as_bytes()[m.start()] as usize]);
+ last_match = m.end();
+ }
+ new.push_str(&text[last_match..]);
+ new
+}