u32hash.rs

//! ```cargo
//! [dependencies]
//! seahash = "3.0"
//! ordermap = "0.2.8"
//! fnv = "1.0"
//! rand = "0.3"
//! bencher = "0.1"
//! ```
#[macro_use]
extern crate bencher;
extern crate rand;
extern crate fnv;
extern crate seahash;

use fnv::FnvHasher;
use std::hash::BuildHasherDefault;
type FnvBuilder = BuildHasherDefault<FnvHasher>;
type ShBuilder = BuildHasherDefault<seahash::SeaHasher>;

use bencher::Bencher;

extern crate ordermap;

//use ordermap::OrderMap;
use std::collections::HashMap;
use std::iter::FromIterator;

use rand::{weak_rng, Rng};

fn shuffled_keys<I>(iter: I) -> Vec<I::Item>
    where I: IntoIterator
{
    let mut v = Vec::from_iter(iter);
    let mut rng = weak_rng();
    rng.shuffle(&mut v);
    v
}

type KeyType = u32;

fn lookup_siphash(b: &mut Bencher) {
    let c = 10_000 as KeyType;
    let mut map = HashMap::with_capacity(c as usize);
    let keys = shuffled_keys(0..c);
    for &key in &keys {
        map.insert(key, 1);
    }
    let lookups = (5000..c).collect::<Vec<_>>();
    b.iter(|| {
        let mut found = 0;
        for key in &lookups {
            found += map.get(key).is_some() as i32;
        }
        found
    });
}

fn lookup_fnv(b: &mut Bencher) {
    let c = 10_000 as KeyType;
    let mut map = HashMap::with_capacity_and_hasher(c as usize, FnvBuilder::default());
    let keys = shuffled_keys(0..c);
    for &key in &keys {
        map.insert(key, 1);
    }
    let lookups = (5000..c).collect::<Vec<_>>();
    b.iter(|| {
        let mut found = 0;
        for key in &lookups {
            found += map.get(key).is_some() as i32;
        }
        found
    });
}

fn lookup_seahash(b: &mut Bencher) {
    let c = 10_000 as KeyType;
    let mut map = HashMap::with_capacity_and_hasher(c as usize, ShBuilder::default());
    let keys = shuffled_keys(0..c);
    for &key in &keys {
        map.insert(key, 1);
    }
    let lookups = (5000..c).collect::<Vec<_>>();
    b.iter(|| {
        let mut found = 0;
        for key in &lookups {
            found += map.get(key).is_some() as i32;
        }
        found
    });
}


benchmark_group!(benches,
                 lookup_siphash,
                 lookup_fnv,
                 lookup_seahash);
                            
benchmark_main!(benches);