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|
//! Default hasher for IndexMap.
use core::fmt::Debug;
use core::hash::{BuildHasher, Hasher};
use foldhash::fast::RandomState;
use static_assertions::assert_impl_all;
/// Default hash builder for IndexMap.
#[derive(Clone, Debug, Default)]
pub struct DefaultHashBuilder {
inner: RandomState,
}
impl BuildHasher for DefaultHashBuilder {
type Hasher = DefaultHasher;
#[inline(always)]
fn build_hasher(&self) -> Self::Hasher {
DefaultHasher {
inner: self.inner.build_hasher(),
}
}
}
/// Default hasher.
#[derive(Clone)]
pub struct DefaultHasher {
inner: <RandomState as BuildHasher>::Hasher,
}
impl Hasher for DefaultHasher {
#[inline(always)]
fn write(&mut self, bytes: &[u8]) {
self.inner.write(bytes);
}
#[inline(always)]
fn write_u8(&mut self, i: u8) {
self.inner.write_u8(i);
}
#[inline(always)]
fn write_u16(&mut self, i: u16) {
self.inner.write_u16(i);
}
#[inline(always)]
fn write_u32(&mut self, i: u32) {
self.inner.write_u32(i);
}
#[inline(always)]
fn write_u64(&mut self, i: u64) {
self.inner.write_u64(i);
}
#[inline(always)]
fn write_u128(&mut self, i: u128) {
self.inner.write_u128(i);
}
#[inline(always)]
fn write_usize(&mut self, i: usize) {
self.inner.write_usize(i);
}
#[inline(always)]
fn write_i8(&mut self, i: i8) {
self.inner.write_i8(i);
}
#[inline(always)]
fn write_i16(&mut self, i: i16) {
self.inner.write_i16(i);
}
#[inline(always)]
fn write_i32(&mut self, i: i32) {
self.inner.write_i32(i);
}
#[inline(always)]
fn write_i64(&mut self, i: i64) {
self.inner.write_i64(i);
}
#[inline(always)]
fn write_i128(&mut self, i: i128) {
self.inner.write_i128(i);
}
#[inline(always)]
fn write_isize(&mut self, i: isize) {
self.inner.write_isize(i);
}
#[inline(always)]
fn finish(&self) -> u64 {
self.inner.finish()
}
}
assert_impl_all!(DefaultHashBuilder: Clone, Debug, Default, BuildHasher);
assert_impl_all!(DefaultHasher: Clone, Hasher);
#[cfg(test)]
mod tests {
use super::*;
use core::hash::{BuildHasher, Hasher};
#[test]
fn write_order_affects_hash() {
let builder = DefaultHashBuilder::default();
let hasher = builder.build_hasher();
let mut h1 = hasher.clone();
let mut h2 = hasher.clone();
h1.write(b"a");
h1.write(b"b");
h2.write(b"b");
h2.write(b"a");
assert_ne!(h1.finish(), h2.finish());
}
}
|
