Add formal benchmarking code

2021/Cargo.toml

@@ -9,6 +9,13 @@ clap = { version = "3.0.0-rc.0", features = ["derive"] }
 itertools = "0.10"
 nom = "7"
 
+[dev-dependencies]
+criterion = "0.3"
+
 [profile.release]
 # Keep debug information in release for better flamegraphs
 debug = true
+
+[[bench]]
+name = "days"
+harness = false

2021/benches/days.rs

@@ -0,0 +1,42 @@
+use std::fs::File;
+use std::io::Read;
+
+use aoc_2021::get_implementation;
+use criterion::criterion_group;
+use criterion::criterion_main;
+use criterion::BenchmarkId;
+use criterion::Criterion;
+
+const DAYS_IMPLEMENTED: usize = 12;
+
+fn read_input(day: usize) -> Vec<u8> {
+    let input_path = format!("inputs/{:02}.txt", day);
+
+    let mut buffer = Vec::new();
+    File::open(input_path)
+        .expect("Failed to open input file")
+        .read_to_end(&mut buffer)
+        .expect("Failed to read input file");
+
+    buffer
+}
+
+pub fn benchmark_days(c: &mut Criterion) {
+    for day in 1..=DAYS_IMPLEMENTED {
+        let input = read_input(day);
+
+        let part1 = get_implementation(day, false);
+        let part2 = get_implementation(day, true);
+
+        c.bench_with_input(BenchmarkId::new("part1", day), &input, |b, i| {
+            b.iter(|| part1(&mut &i[..]));
+        });
+
+        c.bench_with_input(BenchmarkId::new("part2", day), &input, |b, i| {
+            b.iter(|| part2(&mut &i[..]));
+        });
+    }
+}
+
+criterion_group!(benches, benchmark_days);
+criterion_main!(benches);