rust/library/core/tests/hash/mod.rs
2021-08-15 13:00:25 -04:00

149 lines
3.3 KiB
Rust

mod sip;
use std::default::Default;
use std::hash::{BuildHasher, Hash, Hasher};
use std::rc::Rc;
struct MyHasher {
hash: u64,
}
impl Default for MyHasher {
fn default() -> MyHasher {
MyHasher { hash: 0 }
}
}
impl Hasher for MyHasher {
fn write(&mut self, buf: &[u8]) {
for byte in buf {
self.hash += *byte as u64;
}
}
fn finish(&self) -> u64 {
self.hash
}
}
#[test]
fn test_writer_hasher() {
fn hash<T: Hash>(t: &T) -> u64 {
let mut s = MyHasher { hash: 0 };
t.hash(&mut s);
s.finish()
}
assert_eq!(hash(&()), 0);
assert_eq!(hash(&5_u8), 5);
assert_eq!(hash(&5_u16), 5);
assert_eq!(hash(&5_u32), 5);
assert_eq!(hash(&5_u64), 5);
assert_eq!(hash(&5_usize), 5);
assert_eq!(hash(&5_i8), 5);
assert_eq!(hash(&5_i16), 5);
assert_eq!(hash(&5_i32), 5);
assert_eq!(hash(&5_i64), 5);
assert_eq!(hash(&5_isize), 5);
assert_eq!(hash(&false), 0);
assert_eq!(hash(&true), 1);
assert_eq!(hash(&'a'), 97);
let s: &str = "a";
assert_eq!(hash(&s), 97 + 0xFF);
let s: Box<str> = String::from("a").into_boxed_str();
assert_eq!(hash(&s), 97 + 0xFF);
let s: Rc<&str> = Rc::new("a");
assert_eq!(hash(&s), 97 + 0xFF);
let cs: &[u8] = &[1, 2, 3];
assert_eq!(hash(&cs), 9);
let cs: Box<[u8]> = Box::new([1, 2, 3]);
assert_eq!(hash(&cs), 9);
let cs: Rc<[u8]> = Rc::new([1, 2, 3]);
assert_eq!(hash(&cs), 9);
let ptr = 5_usize as *const i32;
assert_eq!(hash(&ptr), 5);
let ptr = 5_usize as *mut i32;
assert_eq!(hash(&ptr), 5);
if cfg!(miri) {
// Miri cannot hash pointers
return;
}
let cs: &mut [u8] = &mut [1, 2, 3];
let ptr = cs.as_ptr();
let slice_ptr = cs as *const [u8];
assert_eq!(hash(&slice_ptr), hash(&ptr) + cs.len() as u64);
let slice_ptr = cs as *mut [u8];
assert_eq!(hash(&slice_ptr), hash(&ptr) + cs.len() as u64);
}
struct Custom {
hash: u64,
}
struct CustomHasher {
output: u64,
}
impl Hasher for CustomHasher {
fn finish(&self) -> u64 {
self.output
}
fn write(&mut self, _: &[u8]) {
panic!()
}
fn write_u64(&mut self, data: u64) {
self.output = data;
}
}
impl Default for CustomHasher {
fn default() -> CustomHasher {
CustomHasher { output: 0 }
}
}
impl Hash for Custom {
fn hash<H: Hasher>(&self, state: &mut H) {
state.write_u64(self.hash);
}
}
#[test]
fn test_custom_state() {
fn hash<T: Hash>(t: &T) -> u64 {
let mut c = CustomHasher { output: 0 };
t.hash(&mut c);
c.finish()
}
assert_eq!(hash(&Custom { hash: 5 }), 5);
}
// FIXME: Instantiated functions with i128 in the signature is not supported in Emscripten.
// See https://github.com/kripken/emscripten-fastcomp/issues/169
#[cfg(not(target_os = "emscripten"))]
#[test]
fn test_indirect_hasher() {
let mut hasher = MyHasher { hash: 0 };
{
let mut indirect_hasher: &mut dyn Hasher = &mut hasher;
5u32.hash(&mut indirect_hasher);
}
assert_eq!(hasher.hash, 5);
}
#[test]
fn test_build_hasher_object_safe() {
use std::collections::hash_map::{DefaultHasher, RandomState};
let _: &dyn BuildHasher<Hasher = DefaultHasher> = &RandomState::new();
}