use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
use toolchain::lexer;

/// "Speed of light" benchmarking. Intended to capture the absolute fastest throughput a
/// byte-for-byte analysis of an input string is likely to be able to achieve. This gives the
/// other benchmarks a reference comparison for the limiting factors on a given hardware platform.
pub fn string_validation(c: &mut Criterion) {
  let mut group = c.benchmark_group("validate_utf8");
  for size in [1024, 2 * 1024, 4 * 1024, 8 * 1024, 16 * 1024].iter() {
    group.throughput(Throughput::Bytes(*size as u64));
    group.bench_with_input(BenchmarkId::from_parameter(size), size, |b, &size| {
      let mut s = String::new();
      while s.len() < size {
        s.push_str("abcdefghijklmnopqrstuvwxyz012345");
      }

      b.iter(|| {
        lexer::validate_utf8(black_box(s.as_bytes()));
      });
    });
  }
  group.finish();
}

criterion_group!(speed_of_light, string_validation);
criterion_main!(speed_of_light);