Add criterion benchmarks

Cargo.toml

@@ -12,8 +12,13 @@ edition = "2021"
 rust-version = "1.71.1"
 
 [dev-dependencies]
+criterion = { version = "0.5.1", features = ["html_reports"] }
 paste = "1.0.14"
 
+[[bench]]
+name = "benchmark"
+harness = false
+
 [badges]
 codecov = { repository = "nordzilla/count-digits", branch = "main", service = "github" }
 

benches/benchmark.rs

@@ -0,0 +1,68 @@
+use count_digits::CountDigits;
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion};
+
+macro_rules! bench_function {
+    ($group:expr, $type:ty, $fn:ident, $input:expr) => {
+        $group.bench_with_input(
+            BenchmarkId::new(stringify!($type), $input),
+            $input,
+            |b, n| b.iter(|| CountDigits::$fn(black_box(*n as $type))),
+        );
+    };
+}
+
+macro_rules! bench_group {
+    ($criterion:expr, $group_name:ident, $fn:ident, $input:expr, $($type:ty),+ $(,)?) => {{
+        paste::paste! {
+            let mut group = $criterion.benchmark_group(stringify!([<$group_name _ $fn>]));
+            for input in $input.iter() {
+                $(bench_function!(group, $type, $fn, input);)+
+            }
+            group.finish();
+        }
+    }};
+}
+
+macro_rules! create_bench {
+    ($fn:ident) => {
+        fn $fn(c: &mut Criterion) {
+            bench_group!(
+                c,
+                signed,
+                $fn,
+                [i8::MIN, -64, 0, 64, i8::MAX],
+                i8,
+                i16,
+                i32,
+                i64,
+                i128
+            );
+            bench_group!(
+                c,
+                unsigned,
+                $fn,
+                [u8::MIN, 64, 128, 192, u8::MAX],
+                u8,
+                u16,
+                u32,
+                u64,
+                u128
+            );
+        }
+    };
+}
+
+create_bench!(count_bits);
+create_bench!(count_octal_digits);
+create_bench!(count_digits);
+create_bench!(count_hex_digits);
+
+criterion_group!(
+    benches,
+    count_bits,
+    count_octal_digits,
+    count_digits,
+    count_hex_digits
+);
+
+criterion_main!(benches);