From 2b65380c563312389644b36c8db3b930ce466e6a Mon Sep 17 00:00:00 2001
From: Zachary Dremann <dremann@gmail.com>
Date: Sat, 14 Oct 2023 15:47:07 -0400
Subject: [PATCH] Add the "teddy" algorithm from aho-corasick

Per suggestion from @BurntSushi [here](https://github.com/tafia/quick-xml/pull/664#issuecomment-1763371610)

On my M1, tt appears to be slower but competitive with memchr up to memchr3,
then start being the from 5-16
---
 Cargo.toml            |  1 +
 benches/benchmarks.rs | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/Cargo.toml b/Cargo.toml
index 064f8c6..1bccce0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,6 +20,7 @@ benchmarks = []
 pattern = []
 
 [dev-dependencies]
+aho-corasick = "1.1.0"
 proptest = "1.0.0"
 lazy_static = "1.0.0"
 region = "3.0.0"
diff --git a/benches/benchmarks.rs b/benches/benchmarks.rs
index 1f2124d..4e9a3ef 100644
--- a/benches/benchmarks.rs
+++ b/benches/benchmarks.rs
@@ -40,6 +40,10 @@ fn spaces(c: &mut Criterion) {
     group.bench_function("stdlib_iter_position", |b| {
         b.iter(|| haystack.bytes().position(|c| c == b' '));
     });
+    group.bench_function("teddy", |b| {
+        let searcher = aho_corasick::packed::Searcher::new([" "]).unwrap();
+        b.iter(|| searcher.find(&haystack).map(|m| m.start()));
+    });
     group.bench_function("memchr", |b| {
         b.iter(|| memchr::memchr(b' ', haystack.as_bytes()));
     });
@@ -69,6 +73,10 @@ fn xml3(c: &mut Criterion) {
                 .position(|c| c == b'<' || c == b'>' || c == b'&')
         });
     });
+    group.bench_function("teddy", |b| {
+        let searcher = aho_corasick::packed::Searcher::new(["<", ">", "&"]).unwrap();
+        b.iter(|| searcher.find(&haystack).map(|m| m.start()));
+    });
     group.bench_function("memchr", |b| {
         b.iter(|| memchr::memchr3(b'<', b'>', b'&', haystack.as_bytes()));
     });
@@ -98,6 +106,10 @@ fn xml5(c: &mut Criterion) {
                 .position(|c| c == b'<' || c == b'>' || c == b'&' || c == b'\'' || c == b'"')
         });
     });
+    group.bench_function("teddy", |b| {
+        let searcher = aho_corasick::packed::Searcher::new(["<", ">", "&", "'", "\""]).unwrap();
+        b.iter(|| searcher.find(&haystack).map(|m| m.start()));
+    });
     group.bench_function("memchr", |b| {
         b.iter(|| {
             let bytes = haystack.as_bytes();
@@ -174,6 +186,10 @@ fn big_16(c: &mut Criterion) {
             })
         });
     });
+    group.bench_function("teddy", |b| {
+        let searcher = aho_corasick::packed::Searcher::new(b"ABCDEFGHIJKLMNOP".iter().map(|b| std::array::from_ref(b))).unwrap();
+        b.iter(|| searcher.find(&haystack).map(|m| m.start()));
+    });
     group.bench_function("memchr", |b| {
         b.iter(|| {
             let bytes = haystack.as_bytes();
@@ -253,6 +269,10 @@ fn big_16(c: &mut Criterion) {
             })
         });
     });
+    group.bench_function("teddy", |b| {
+        let searcher = aho_corasick::packed::Searcher::new(b"ABCDEFGHIJKLMNOP".iter().map(|b| std::array::from_ref(b))).unwrap();
+        b.iter(|| searcher.find(&haystack).map(|m| m.start()));
+    });
     group.bench_function("memchr", |b| {
         b.iter(|| {
             let bytes = haystack.as_bytes();