Struct HasherFnv

pub struct HasherFnv<T> { /* private fields */ }

Available on crate features hash and cast only.

A Fowler–Noll–Vo hasher, implemented for u32, u64, u128 & usize.

It uses the fnv-1a variation which gives better avalanche characteristics.

See

• https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function
• http://www.isthe.com/chongo/tech/comp/fnv

Implementations

impl HasherFnv<u32>

pub const fn new() -> Self

Returns a default FNV hasher.

pub const fn with(input: &[u8]) -> Self

Returns an FNV hasher with the given input data.

pub const fn get(&self) -> u32

Returns the current hash value.

pub const fn get_hash_mod_lazy(&self, range: u32) -> u32

Returns the hash value with lazy mod mapping to the given range.

pub const fn get_hash_mod_retry(&self, range: u32) -> u32

Returns the hash value with retried mod mapping to the given range.

pub const fn get_hash_n_bits(&self, n: usize) -> u32

Returns the hash value xor folded to n bits.

Panics

Panics in debug if n exceeds u32::BITS.

pub const fn update(&mut self, input: &[u8])

Updates the hasher with more data.

Allows the hasher to receive additional bytes incrementally.

pub const fn reset(&mut self)

Resets the inner state to the default basis value.

pub const fn hash(input: &[u8]) -> u32

Computes the FNV hash of the provided byte slice.

pub const fn hash_mod_lazy(input: &[u8], range: u32) -> u32

Maps the computed FNV hash to the given range using lazy mod mapping.

This method only does an additional mod at the end. But there’s a small bias against the larger values.

pub const fn hash_mod_retry(input: &[u8], range: u32) -> u32

Maps the computed FNV hash to the given range using retried mod mapping.

pub const fn hash_n_bits(input: &[u8], n: usize) -> u32

Computes the FNV hash of the provided byte slice, xor folded to n bits.

Panics

Panics in debug if n exceeds u32::BITS.

pub const fn fold_hash(hash: u32, n: usize) -> u32

Reduces a hash to n bits using xor folding.

Panics

Panics in debug if n exceeds u32::BITS.

pub const fn mod_retry_hash(hash: u32, range: u32) -> u32

Maps a hash to the given range using retried mod mapping.

Ensures that the hash value is uniform and unbiased within the range.

impl HasherFnv<u64>

pub const fn new() -> Self

Returns a default FNV hasher.

pub const fn with(input: &[u8]) -> Self

Returns an FNV hasher with the given input data.

pub const fn get(&self) -> u64

Returns the current hash value.

pub const fn get_hash_mod_lazy(&self, range: u64) -> u64

Returns the hash value with lazy mod mapping to the given range.

pub const fn get_hash_mod_retry(&self, range: u64) -> u64

Returns the hash value with retried mod mapping to the given range.

pub const fn get_hash_n_bits(&self, n: usize) -> u64

Returns the hash value xor folded to n bits.

Panics

Panics in debug if n exceeds u64::BITS.

pub const fn update(&mut self, input: &[u8])

Updates the hasher with more data.

Allows the hasher to receive additional bytes incrementally.

pub const fn reset(&mut self)

Resets the inner state to the default basis value.

pub const fn hash(input: &[u8]) -> u64

Computes the FNV hash of the provided byte slice.

pub const fn hash_mod_lazy(input: &[u8], range: u64) -> u64

Maps the computed FNV hash to the given range using lazy mod mapping.

This method only does an additional mod at the end. But there’s a small bias against the larger values.

pub const fn hash_mod_retry(input: &[u8], range: u64) -> u64

Maps the computed FNV hash to the given range using retried mod mapping.

pub const fn hash_n_bits(input: &[u8], n: usize) -> u64

Computes the FNV hash of the provided byte slice, xor folded to n bits.

Panics

Panics in debug if n exceeds u64::BITS.

pub const fn fold_hash(hash: u64, n: usize) -> u64

Reduces a hash to n bits using xor folding.

Panics

Panics in debug if n exceeds u64::BITS.

pub const fn mod_retry_hash(hash: u64, range: u64) -> u64

Maps a hash to the given range using retried mod mapping.

Ensures that the hash value is uniform and unbiased within the range.

impl HasherFnv<u128>

pub const fn new() -> Self

Returns a default FNV hasher.

pub const fn with(input: &[u8]) -> Self

Returns an FNV hasher with the given input data.

pub const fn get(&self) -> u128

Returns the current hash value.

pub const fn get_hash_mod_lazy(&self, range: u128) -> u128

Returns the hash value with lazy mod mapping to the given range.

pub const fn get_hash_mod_retry(&self, range: u128) -> u128

Returns the hash value with retried mod mapping to the given range.

pub const fn get_hash_n_bits(&self, n: usize) -> u128

Returns the hash value xor folded to n bits.

Panics

Panics in debug if n exceeds u128::BITS.

pub const fn update(&mut self, input: &[u8])

Updates the hasher with more data.

Allows the hasher to receive additional bytes incrementally.

pub const fn reset(&mut self)

Resets the inner state to the default basis value.

pub const fn hash(input: &[u8]) -> u128

Computes the FNV hash of the provided byte slice.

pub const fn hash_mod_lazy(input: &[u8], range: u128) -> u128

Maps the computed FNV hash to the given range using lazy mod mapping.

This method only does an additional mod at the end. But there’s a small bias against the larger values.

pub const fn hash_mod_retry(input: &[u8], range: u128) -> u128

Maps the computed FNV hash to the given range using retried mod mapping.

pub const fn hash_n_bits(input: &[u8], n: usize) -> u128

Computes the FNV hash of the provided byte slice, xor folded to n bits.

Panics

Panics in debug if n exceeds u128::BITS.

pub const fn fold_hash(hash: u128, n: usize) -> u128

Reduces a hash to n bits using xor folding.

Panics

Panics in debug if n exceeds u128::BITS.

pub const fn mod_retry_hash(hash: u128, range: u128) -> u128

Maps a hash to the given range using retried mod mapping.

Ensures that the hash value is uniform and unbiased within the range.

impl HasherFnv<usize>

pub const fn new() -> Self

Returns a default FNV hasher.

pub const fn with(input: &[u8]) -> Self

Returns an FNV hasher with the given input data.

pub const fn get(&self) -> usize

Returns the current hash value.

pub const fn get_hash_mod_lazy(&self, range: usize) -> usize

Returns the hash value with lazy mod mapping to the given range.

pub const fn get_hash_mod_retry(&self, range: usize) -> usize

Returns the hash value with retried mod mapping to the given range.

pub const fn get_hash_n_bits(&self, n: usize) -> usize

Returns the hash value xor folded to n bits.

Panics

Panics in debug if n exceeds usize::BITS.

pub const fn update(&mut self, input: &[u8])

Updates the hasher with more data.

Allows the hasher to receive additional bytes incrementally.

pub const fn reset(&mut self)

Resets the inner state to the default basis value.

pub const fn hash(input: &[u8]) -> usize

Computes the FNV hash of the provided byte slice.

pub const fn hash_mod_lazy(input: &[u8], range: usize) -> usize

Maps the computed FNV hash to the given range using lazy mod mapping.

This method only does an additional mod at the end. But there’s a small bias against the larger values.

pub const fn hash_mod_retry(input: &[u8], range: usize) -> usize

Maps the computed FNV hash to the given range using retried mod mapping.

pub const fn hash_n_bits(input: &[u8], n: usize) -> usize

Computes the FNV hash of the provided byte slice, xor folded to n bits.

Panics

Panics in debug if n exceeds usize::BITS.

pub const fn fold_hash(hash: usize, n: usize) -> usize

Reduces a hash to n bits using xor folding.

Panics

Panics in debug if n exceeds usize::BITS.

pub const fn mod_retry_hash(hash: usize, range: usize) -> usize

Maps a hash to the given range using retried mod mapping.

Ensures that the hash value is uniform and unbiased within the range.

Trait Implementations

impl<T: Clone> Clone for HasherFnv<T>

fn clone(&self) -> HasherFnv<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ConstDefault for HasherFnv<u128>

const DEFAULT: Self

Returns the compile-time “default value” for a type.

impl ConstDefault for HasherFnv<u32>

const DEFAULT: Self

Returns the compile-time “default value” for a type.

impl ConstDefault for HasherFnv<u64>

const DEFAULT: Self

Returns the compile-time “default value” for a type.

impl ConstDefault for HasherFnv<usize>

const DEFAULT: Self

Returns the compile-time “default value” for a type.

impl<T: Debug> Debug for HasherFnv<T>

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

Formats the value using the given formatter.

impl Default for HasherFnv<u128>

fn default() -> Self

Returns the “default value” for a type.

impl Default for HasherFnv<u32>

fn default() -> Self

Returns the “default value” for a type.

impl Default for HasherFnv<u64>

fn default() -> Self

Returns the “default value” for a type.

impl Default for HasherFnv<usize>

fn default() -> Self

Returns the “default value” for a type.

impl Hasher for HasherFnv<u128>

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

Writes some data into this Hasher.

fn finish(&self) -> u64

Returns the hash value for the values written so far.

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_u64(&mut self, i: u64)

Writes a single u64 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.

impl Hasher for HasherFnv<u32>

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

Writes some data into this Hasher.

fn finish(&self) -> u64

Returns the hash value for the values written so far.

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_u64(&mut self, i: u64)

Writes a single u64 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.

impl Hasher for HasherFnv<u64>

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

Writes some data into this Hasher.

fn finish(&self) -> u64

Returns the hash value for the values written so far.

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_u64(&mut self, i: u64)

Writes a single u64 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.

impl Hasher for HasherFnv<usize>

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

Writes some data into this Hasher.

fn finish(&self) -> u64

Returns the hash value for the values written so far.

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_u64(&mut self, i: u64)

Writes a single u64 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.

impl<T: PartialEq> PartialEq for HasherFnv<T>

fn eq(&self, other: &HasherFnv<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Copy> Copy for HasherFnv<T>

impl<T: Eq> Eq for HasherFnv<T>

impl<T> StructuralPartialEq for HasherFnv<T>