| use rand::Rng; |
| use test::{black_box, Bencher}; |
| |
| macro_rules! int_log_bench { |
| ($t:ty, $predictable:ident, $random:ident, $random_small:ident) => { |
| #[bench] |
| fn $predictable(bench: &mut Bencher) { |
| bench.iter(|| { |
| for n in 0..(<$t>::BITS / 8) { |
| for i in 1..=(100 as $t) { |
| let x = black_box(i << (n * 8)); |
| black_box(x.ilog10()); |
| } |
| } |
| }); |
| } |
| |
| #[bench] |
| fn $random(bench: &mut Bencher) { |
| let mut rng = crate::bench_rng(); |
| /* Exponentially distributed random numbers from the whole range of the type. */ |
| let numbers: Vec<$t> = (0..256) |
| .map(|_| { |
| let x = rng.gen::<$t>() >> rng.gen_range(0, <$t>::BITS); |
| if x != 0 { x } else { 1 } |
| }) |
| .collect(); |
| bench.iter(|| { |
| for x in &numbers { |
| black_box(black_box(x).ilog10()); |
| } |
| }); |
| } |
| |
| #[bench] |
| fn $random_small(bench: &mut Bencher) { |
| let mut rng = crate::bench_rng(); |
| /* Exponentially distributed random numbers from the range 0..256. */ |
| let numbers: Vec<$t> = (0..256) |
| .map(|_| { |
| let x = (rng.gen::<u8>() >> rng.gen_range(0, u8::BITS)) as $t; |
| if x != 0 { x } else { 1 } |
| }) |
| .collect(); |
| bench.iter(|| { |
| for x in &numbers { |
| black_box(black_box(x).ilog10()); |
| } |
| }); |
| } |
| }; |
| } |
| |
| int_log_bench! {u8, u8_log10_predictable, u8_log10_random, u8_log10_random_small} |
| int_log_bench! {u16, u16_log10_predictable, u16_log10_random, u16_log10_random_small} |
| int_log_bench! {u32, u32_log10_predictable, u32_log10_random, u32_log10_random_small} |
| int_log_bench! {u64, u64_log10_predictable, u64_log10_random, u64_log10_random_small} |
| int_log_bench! {u128, u128_log10_predictable, u128_log10_random, u128_log10_random_small} |