pub struct AHasher { /* private fields */ }
Expand description
A Hasher
for hashing an arbitrary stream of bytes.
Instances of AHasher
represent state that is updated while hashing data.
Each method updates the internal state based on the new data provided. Once
all of the data has been provided, the resulting hash can be obtained by calling
finish()
Clone is also provided in case you wish to calculate hashes for two different items that start with the same data.
Implementations§
source§impl AHasher
impl AHasher
sourcepub fn new_with_keys(key1: u128, key2: u128) -> Self
pub fn new_with_keys(key1: u128, key2: u128) -> Self
Creates a new hasher keyed to the provided keys.
Normally hashers are created via AHasher::default()
for fixed keys or RandomState::new()
for randomly
generated keys and RandomState::with_seeds(a,b)
for seeds that are set and can be reused. All of these work at
map creation time (and hence don’t have any overhead on a per-item bais).
This method directly creates the hasher instance and performs no transformation on the provided seeds. This may be useful where a HashBuilder is not desired, such as for testing purposes.
Example
use std::hash::Hasher;
use ahash::AHasher;
let mut hasher = AHasher::new_with_keys(1234, 5678);
hasher.write_u32(1989);
hasher.write_u8(11);
hasher.write_u8(9);
hasher.write(b"Huh?");
println!("Hash is {:x}!", hasher.finish());
Trait Implementations§
source§impl Default for AHasher
impl Default for AHasher
Provides a default Hasher compile time generated constants for keys. This is typically used in conjunction with BuildHasherDefault to create AHashers in order to hash the keys of the map.
Generally it is preferable to use RandomState instead, so that different hashmaps will have different keys. However if fixed keys are desireable this may be used instead.
Example
use std::hash::BuildHasherDefault;
use ahash::{AHasher, RandomState};
use std::collections::HashMap;
let mut map: HashMap<i32, i32, BuildHasherDefault<AHasher>> = HashMap::default();
map.insert(12, 34);
source§fn default() -> AHasher
fn default() -> AHasher
Constructs a new AHasher with compile time generated constants for keys if the
compile-time-rng
feature is enabled. Otherwise the keys will be fixed constants.
This means the keys will be the same from one instance to another,
but different from build to the next. So if it is possible for a potential
attacker to have access to the compiled binary it would be better
to specify keys generated at runtime.
Examples
use ahash::AHasher;
use std::hash::Hasher;
let mut hasher_1 = AHasher::default();
let mut hasher_2 = AHasher::default();
hasher_1.write_u32(1234);
hasher_2.write_u32(1234);
assert_eq!(hasher_1.finish(), hasher_2.finish());
source§impl Hasher for AHasher
impl Hasher for AHasher
Provides methods to hash all of the primitive types.
source§fn write_u128(&mut self, i: u128)
fn write_u128(&mut self, i: u128)
u128
into this hasher.source§fn write_usize(&mut self, i: usize)
fn write_usize(&mut self, i: usize)
usize
into this hasher.1.26.0 · source§fn write_i128(&mut self, i: i128)
fn write_i128(&mut self, i: i128)
i128
into this hasher.1.3.0 · source§fn write_isize(&mut self, i: isize)
fn write_isize(&mut self, i: isize)
isize
into this hasher.source§fn write_length_prefix(&mut self, len: usize)
fn write_length_prefix(&mut self, len: usize)
hasher_prefixfree_extras
)