feat: Add a benchmark harness

Cargo.toml

@@ -17,6 +17,14 @@ maintenance = { status = "actively-developed" }
 rand = { version = "0.8", optional = true }
 thiserror = "1.0"
 
+[dev-dependencies]
+divan = "0.1"
+rand = { version = "0.8" }
+
 [features]
 default = []
 use-rand = ["rand"]
+
+[[bench]]
+name = "kensler"
+harness = false

benches/kensler.rs

@@ -0,0 +1,32 @@
+use divan::Bencher;
+use hashed_permutation::HashedPermutation;
+use rand::seq::SliceRandom;
+use rand::thread_rng;
+use std::num::NonZeroU32;
+
+const SIZES: [u32; 4] = [100, 1000, 10000, 100000];
+const SEED: u32 = 1209;
+
+#[divan::bench(consts = SIZES)]
+fn kensler_shuffle<const N: u32>(bencher: Bencher) {
+    let perm = HashedPermutation::new_with_seed(NonZeroU32::new(N).unwrap(), SEED);
+
+    bencher.bench_local(move || {
+        for i in 0..N {
+            perm.shuffle(i).unwrap();
+        }
+    });
+}
+
+#[divan::bench(consts = SIZES)]
+fn naive_random_shuffle<const N: u32>(bencher: Bencher) {
+    let mut v: Vec<u32> = (0..N).collect();
+    let mut rng = thread_rng();
+    bencher.bench_local(move || {
+        v.shuffle(&mut rng);
+    })
+}
+
+fn main() {
+    divan::main();
+}