Struct KeyHasher 

pub struct KeyHasher { /* private fields */ }

A no-op hasher for pre-hashed Key types.

This hasher is designed for use with Key, which pre-computes its hash at construction time. When Key::hash() is called, it writes the pre-computed hash via write_u64(), and finish() simply returns that value.

This ensures that HashMap<Key, V, BuildHasherDefault<KeyHasher>> lookups work correctly when using raw_entry APIs with pre-computed hashes.

Panics

Panics if finish() is called without first calling write_u64(), or if any write method other than write_u64() is called. This hasher is specifically for pre-hashed keys only.

Trait Implementations

impl Debug for KeyHasher

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for KeyHasher

fn default() -> KeyHasher

Returns the “default value” for a type.

impl Hasher for KeyHasher

fn finish(&self) -> u64

Returns the hash value for the values written so far.

fn write(&mut self, _bytes: &[u8])

Writes some data into this Hasher.

fn write_u64(&mut self, i: u64)

Writes a single u64 into this hasher.

fn write_u8(&mut self, i: u8)

Writes a single u8 into this hasher.

fn write_u16(&mut self, i: u16)

Writes a single u16 into this hasher.

fn write_u32(&mut self, i: u32)

Writes a single u32 into this hasher.

fn write_u128(&mut self, i: u128)

Writes a single u128 into this hasher.

fn write_usize(&mut self, i: usize)

Writes a single usize into this hasher.

fn write_i8(&mut self, i: i8)

Writes a single i8 into this hasher.

fn write_i16(&mut self, i: i16)

Writes a single i16 into this hasher.

fn write_i32(&mut self, i: i32)

Writes a single i32 into this hasher.

fn write_i64(&mut self, i: i64)

Writes a single i64 into this hasher.

fn write_i128(&mut self, i: i128)

Writes a single i128 into this hasher.

fn write_isize(&mut self, i: isize)

Writes a single isize into this hasher.

fn write_length_prefix(&mut self, len: usize)

🔬This is a nightly-only experimental API. (hasher_prefixfree_extras)

Writes a length prefix into this hasher, as part of being prefix-free.

fn write_str(&mut self, s: &str)

🔬This is a nightly-only experimental API. (hasher_prefixfree_extras)

Writes a single str into this hasher.