rust/src/test/bench/core-set.rs
Alex Crichton 511f0b8a3d std: Stabilize the std::hash module
This commit aims to prepare the `std::hash` module for alpha by formalizing its
current interface whileholding off on adding `#[stable]` to the new APIs.  The
current usage with the `HashMap` and `HashSet` types is also reconciled by
separating out composable parts of the design. The primary goal of this slight
redesign is to separate the concepts of a hasher's state from a hashing
algorithm itself.

The primary change of this commit is to separate the `Hasher` trait into a
`Hasher` and a `HashState` trait. Conceptually the old `Hasher` trait was
actually just a factory for various states, but hashing had very little control
over how these states were used. Additionally the old `Hasher` trait was
actually fairly unrelated to hashing.

This commit redesigns the existing `Hasher` trait to match what the notion of a
`Hasher` normally implies with the following definition:

    trait Hasher {
        type Output;
        fn reset(&mut self);
        fn finish(&self) -> Output;
    }

This `Hasher` trait emphasizes that hashing algorithms may produce outputs other
than a `u64`, so the output type is made generic. Other than that, however, very
little is assumed about a particular hasher. It is left up to implementors to
provide specific methods or trait implementations to feed data into a hasher.

The corresponding `Hash` trait becomes:

    trait Hash<H: Hasher> {
        fn hash(&self, &mut H);
    }

The old default of `SipState` was removed from this trait as it's not something
that we're willing to stabilize until the end of time, but the type parameter is
always required to implement `Hasher`. Note that the type parameter `H` remains
on the trait to enable multidispatch for specialization of hashing for
particular hashers.

Note that `Writer` is not mentioned in either of `Hash` or `Hasher`, it is
simply used as part `derive` and the implementations for all primitive types.

With these definitions, the old `Hasher` trait is realized as a new `HashState`
trait in the `collections::hash_state` module as an unstable addition for
now. The current definition looks like:

    trait HashState {
        type Hasher: Hasher;
        fn hasher(&self) -> Hasher;
    }

The purpose of this trait is to emphasize that the one piece of functionality
for implementors is that new instances of `Hasher` can be created.  This
conceptually represents the two keys from which more instances of a
`SipHasher` can be created, and a `HashState` is what's stored in a
`HashMap`, not a `Hasher`.

Implementors of custom hash algorithms should implement the `Hasher` trait, and
only hash algorithms intended for use in hash maps need to implement or worry
about the `HashState` trait.

The entire module and `HashState` infrastructure remains `#[unstable]` due to it
being recently redesigned, but some other stability decision made for the
`std::hash` module are:

* The `Writer` trait remains `#[experimental]` as it's intended to be replaced
  with an `io::Writer` (more details soon).
* The top-level `hash` function is `#[unstable]` as it is intended to be generic
  over the hashing algorithm instead of hardwired to `SipHasher`
* The inner `sip` module is now private as its one export, `SipHasher` is
  reexported in the `hash` module.

And finally, a few changes were made to the default parameters on `HashMap`.

* The `RandomSipHasher` default type parameter was renamed to `RandomState`.
  This renaming emphasizes that it is not a hasher, but rather just state to
  generate hashers. It also moves away from the name "sip" as it may not always
  be implemented as `SipHasher`. This type lives in the
  `std::collections::hash_map` module as `#[unstable]`

* The associated `Hasher` type of `RandomState` is creatively called...
  `Hasher`! This concrete structure lives next to `RandomState` as an
  implemenation of the "default hashing algorithm" used for a `HashMap`. Under
  the hood this is currently implemented as `SipHasher`, but it draws an
  explicit interface for now and allows us to modify the implementation over
  time if necessary.

There are many breaking changes outlined above, and as a result this commit is
a:

[breaking-change]
2015-01-07 12:18:08 -08:00

230 lines
6.6 KiB
Rust

// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// ignore-pretty very bad with line comments
#![feature(unboxed_closures)]
extern crate collections;
extern crate rand;
use std::collections::BTreeSet;
use std::collections::BitvSet;
use std::collections::HashSet;
use std::collections::hash_map::Hasher;
use std::hash::Hash;
use std::os;
use std::time::Duration;
use std::uint;
struct Results {
sequential_ints: Duration,
random_ints: Duration,
delete_ints: Duration,
sequential_strings: Duration,
random_strings: Duration,
delete_strings: Duration,
}
fn timed<F>(result: &mut Duration, op: F) where F: FnOnce() {
*result = Duration::span(op);
}
trait MutableSet<T> {
fn insert(&mut self, k: T);
fn remove(&mut self, k: &T) -> bool;
fn contains(&self, k: &T) -> bool;
}
impl<T: Hash<Hasher> + Eq> MutableSet<T> for HashSet<T> {
fn insert(&mut self, k: T) { self.insert(k); }
fn remove(&mut self, k: &T) -> bool { self.remove(k) }
fn contains(&self, k: &T) -> bool { self.contains(k) }
}
impl<T: Ord> MutableSet<T> for BTreeSet<T> {
fn insert(&mut self, k: T) { self.insert(k); }
fn remove(&mut self, k: &T) -> bool { self.remove(k) }
fn contains(&self, k: &T) -> bool { self.contains(k) }
}
impl MutableSet<uint> for BitvSet {
fn insert(&mut self, k: uint) { self.insert(k); }
fn remove(&mut self, k: &uint) -> bool { self.remove(k) }
fn contains(&self, k: &uint) -> bool { self.contains(k) }
}
impl Results {
pub fn bench_int<T:MutableSet<uint>,
R:rand::Rng,
F:FnMut() -> T>(
&mut self,
rng: &mut R,
num_keys: uint,
rand_cap: uint,
mut f: F) {
{
let mut set = f();
timed(&mut self.sequential_ints, || {
for i in range(0u, num_keys) {
set.insert(i);
}
for i in range(0u, num_keys) {
assert!(set.contains(&i));
}
})
}
{
let mut set = f();
timed(&mut self.random_ints, || {
for _ in range(0, num_keys) {
set.insert(rng.gen::<uint>() % rand_cap);
}
})
}
{
let mut set = f();
for i in range(0u, num_keys) {
set.insert(i);
}
timed(&mut self.delete_ints, || {
for i in range(0u, num_keys) {
assert!(set.remove(&i));
}
})
}
}
pub fn bench_str<T:MutableSet<String>,
R:rand::Rng,
F:FnMut() -> T>(
&mut self,
rng: &mut R,
num_keys: uint,
mut f: F) {
{
let mut set = f();
timed(&mut self.sequential_strings, || {
for i in range(0u, num_keys) {
set.insert(i.to_string());
}
for i in range(0u, num_keys) {
assert!(set.contains(&i.to_string()));
}
})
}
{
let mut set = f();
timed(&mut self.random_strings, || {
for _ in range(0, num_keys) {
let s = rng.gen::<uint>().to_string();
set.insert(s);
}
})
}
{
let mut set = f();
for i in range(0u, num_keys) {
set.insert(i.to_string());
}
timed(&mut self.delete_strings, || {
for i in range(0u, num_keys) {
assert!(set.remove(&i.to_string()));
}
})
}
}
}
fn write_header(header: &str) {
println!("{}", header);
}
fn write_row(label: &str, value: Duration) {
println!("{:30} {} s\n", label, value);
}
fn write_results(label: &str, results: &Results) {
write_header(label);
write_row("sequential_ints", results.sequential_ints);
write_row("random_ints", results.random_ints);
write_row("delete_ints", results.delete_ints);
write_row("sequential_strings", results.sequential_strings);
write_row("random_strings", results.random_strings);
write_row("delete_strings", results.delete_strings);
}
fn empty_results() -> Results {
Results {
sequential_ints: Duration::seconds(0),
random_ints: Duration::seconds(0),
delete_ints: Duration::seconds(0),
sequential_strings: Duration::seconds(0),
random_strings: Duration::seconds(0),
delete_strings: Duration::seconds(0),
}
}
fn main() {
let args = os::args();
let args = args.as_slice();
let num_keys = {
if args.len() == 2 {
args[1].parse::<uint>().unwrap()
} else {
100 // woefully inadequate for any real measurement
}
};
let seed: &[_] = &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
let max = 200000;
{
let mut rng: rand::IsaacRng = rand::SeedableRng::from_seed(seed);
let mut results = empty_results();
results.bench_int(&mut rng, num_keys, max, || {
let s: HashSet<uint> = HashSet::new();
s
});
results.bench_str(&mut rng, num_keys, || {
let s: HashSet<String> = HashSet::new();
s
});
write_results("collections::HashSet", &results);
}
{
let mut rng: rand::IsaacRng = rand::SeedableRng::from_seed(seed);
let mut results = empty_results();
results.bench_int(&mut rng, num_keys, max, || {
let s: BTreeSet<uint> = BTreeSet::new();
s
});
results.bench_str(&mut rng, num_keys, || {
let s: BTreeSet<String> = BTreeSet::new();
s
});
write_results("collections::BTreeSet", &results);
}
{
let mut rng: rand::IsaacRng = rand::SeedableRng::from_seed(seed);
let mut results = empty_results();
results.bench_int(&mut rng, num_keys, max, || BitvSet::new());
write_results("collections::bitv::BitvSet", &results);
}
}