81 lines
1.7 KiB
Rust
81 lines
1.7 KiB
Rust
//! A none hashing [`Hasher`] implementation.
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use std::{
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hash::{BuildHasher, Hasher},
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marker::PhantomData,
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};
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pub type NoHashHashMap<K, V> = std::collections::HashMap<K, V, NoHashHasherBuilder<K>>;
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pub type NoHashHashSet<K> = std::collections::HashSet<K, NoHashHasherBuilder<K>>;
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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pub struct NoHashHasherBuilder<T>(PhantomData<T>);
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impl<T> Default for NoHashHasherBuilder<T> {
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fn default() -> Self {
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Self(Default::default())
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}
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}
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pub trait NoHashHashable {}
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impl NoHashHashable for usize {}
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impl NoHashHashable for u32 {}
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pub struct NoHashHasher(u64);
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impl<T: NoHashHashable> BuildHasher for NoHashHasherBuilder<T> {
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type Hasher = NoHashHasher;
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fn build_hasher(&self) -> Self::Hasher {
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NoHashHasher(0)
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}
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}
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impl Hasher for NoHashHasher {
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fn finish(&self) -> u64 {
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self.0
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}
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fn write(&mut self, _: &[u8]) {
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unimplemented!("NoHashHasher should only be used for hashing primitive integers")
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}
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fn write_u8(&mut self, i: u8) {
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self.0 = i as u64;
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}
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fn write_u16(&mut self, i: u16) {
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self.0 = i as u64;
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}
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fn write_u32(&mut self, i: u32) {
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self.0 = i as u64;
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}
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fn write_u64(&mut self, i: u64) {
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self.0 = i as u64;
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}
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fn write_usize(&mut self, i: usize) {
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self.0 = i as u64;
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}
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fn write_i8(&mut self, i: i8) {
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self.0 = i as u64;
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}
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fn write_i16(&mut self, i: i16) {
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self.0 = i as u64;
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}
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fn write_i32(&mut self, i: i32) {
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self.0 = i as u64;
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}
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fn write_i64(&mut self, i: i64) {
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self.0 = i as u64;
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}
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fn write_isize(&mut self, i: isize) {
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self.0 = i as u64;
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}
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}
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