use binggan::{black_box, plugins::*, BenchRunner, PeakMemAlloc, INSTRUMENTED_SYSTEM};

#[global_allocator]
pub static GLOBAL: &PeakMemAlloc<std::alloc::System> = &INSTRUMENTED_SYSTEM;

pub fn factorial(mut n: usize) -> usize {
    let mut result = 1usize;
    while n > 0 {
        result = result.wrapping_mul(black_box(n));
        n -= 1;
    }
    result
}

fn bench_factorial() {
    let mut runner = BenchRunner::new();
    // Set the peak mem allocator. This will enable peak memory reporting.
    runner.add_plugin(PeakMemAllocPlugin::new(GLOBAL));

    for val in [100, 400] {
        runner.bench_function(format!("factorial {}", val), move |_| {
            factorial(black_box(val));
        });
    }

    let mut group = runner.new_group();
    group.register("factorial 100", |()| {
        factorial(black_box(100));
    });
    group.run();
}

fn main() {
    bench_factorial();
}