File: hasher.rs

package info (click to toggle)
chromium 135.0.7049.95-1~deb12u1
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 5,959,392 kB
  • sloc: cpp: 34,198,526; ansic: 7,100,035; javascript: 3,985,800; python: 1,395,489; asm: 896,754; xml: 722,891; pascal: 180,504; sh: 94,909; perl: 88,388; objc: 79,739; sql: 53,020; cs: 41,358; fortran: 24,137; makefile: 22,501; php: 13,699; tcl: 10,142; yacc: 8,822; ruby: 7,350; lisp: 3,096; lex: 1,327; ada: 727; jsp: 228; awk: 197; sed: 36
file content (65 lines) | stat: -rw-r--r-- 1,369 bytes parent folder | download | duplicates (16)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
//! Sanity check that alternate hashers work correctly.

#![cfg(not(miri))] // FIXME: takes too long

use hashbrown::HashSet;
use std::hash::{BuildHasher, BuildHasherDefault, Hasher};

fn check<S: BuildHasher + Default>() {
    let range = 0..1_000;

    let mut set = HashSet::<i32, S>::default();
    set.extend(range.clone());

    assert!(!set.contains(&i32::MIN));
    assert!(!set.contains(&(range.start - 1)));
    for i in range.clone() {
        assert!(set.contains(&i));
    }
    assert!(!set.contains(&range.end));
    assert!(!set.contains(&i32::MAX));
}

/// Use hashbrown's default hasher.
#[test]
fn default() {
    check::<hashbrown::DefaultHashBuilder>();
}

/// Use std's default hasher.
#[test]
fn random_state() {
    check::<std::collections::hash_map::RandomState>();
}

/// Use a constant 0 hash.
#[test]
fn zero() {
    #[derive(Default)]
    struct ZeroHasher;

    impl Hasher for ZeroHasher {
        fn finish(&self) -> u64 {
            0
        }
        fn write(&mut self, _: &[u8]) {}
    }

    check::<BuildHasherDefault<ZeroHasher>>();
}

/// Use a constant maximum hash.
#[test]
fn max() {
    #[derive(Default)]
    struct MaxHasher;

    impl Hasher for MaxHasher {
        fn finish(&self) -> u64 {
            u64::MAX
        }
        fn write(&mut self, _: &[u8]) {}
    }

    check::<BuildHasherDefault<MaxHasher>>();
}