Trait tract_core::internal::Hash
1.0.0 · source · pub trait Hash {
// Required method
fn hash<H>(&self, state: &mut H)
where H: Hasher;
// Provided method
fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher,
Self: Sized { ... }
}
Expand description
A hashable type.
Types implementing Hash
are able to be hash
ed with an instance of
Hasher
.
§Implementing Hash
You can derive Hash
with #[derive(Hash)]
if all fields implement Hash
.
The resulting hash will be the combination of the values from calling
hash
on each field.
#[derive(Hash)]
struct Rustacean {
name: String,
country: String,
}
If you need more control over how a value is hashed, you can of course
implement the Hash
trait yourself:
use std::hash::{Hash, Hasher};
struct Person {
id: u32,
name: String,
phone: u64,
}
impl Hash for Person {
fn hash<H: Hasher>(&self, state: &mut H) {
self.id.hash(state);
self.phone.hash(state);
}
}
§Hash
and Eq
When implementing both Hash
and Eq
, it is important that the following
property holds:
k1 == k2 -> hash(k1) == hash(k2)
In other words, if two keys are equal, their hashes must also be equal.
HashMap
and HashSet
both rely on this behavior.
Thankfully, you won’t need to worry about upholding this property when
deriving both Eq
and Hash
with #[derive(PartialEq, Eq, Hash)]
.
Violating this property is a logic error. The behavior resulting from a logic error is not
specified, but users of the trait must ensure that such logic errors do not result in
undefined behavior. This means that unsafe
code must not rely on the correctness of these
methods.
§Prefix collisions
Implementations of hash
should ensure that the data they
pass to the Hasher
are prefix-free. That is,
values which are not equal should cause two different sequences of values to be written,
and neither of the two sequences should be a prefix of the other.
For example, the standard implementation of Hash
for &str
passes an extra
0xFF
byte to the Hasher
so that the values ("ab", "c")
and ("a", "bc")
hash differently.
§Portability
Due to differences in endianness and type sizes, data fed by Hash
to a Hasher
should not be considered portable across platforms. Additionally the data passed by most
standard library types should not be considered stable between compiler versions.
This means tests shouldn’t probe hard-coded hash values or data fed to a Hasher
and
instead should check consistency with Eq
.
Serialization formats intended to be portable between platforms or compiler versions should
either avoid encoding hashes or only rely on Hash
and Hasher
implementations that
provide additional guarantees.
Required Methods§
Provided Methods§
1.3.0 · sourcefn hash_slice<H>(data: &[Self], state: &mut H)
fn hash_slice<H>(data: &[Self], state: &mut H)
Feeds a slice of this type into the given Hasher
.
This method is meant as a convenience, but its implementation is
also explicitly left unspecified. It isn’t guaranteed to be
equivalent to repeated calls of hash
and implementations of
Hash
should keep that in mind and call hash
themselves
if the slice isn’t treated as a whole unit in the PartialEq
implementation.
For example, a VecDeque
implementation might naïvely call
as_slices
and then hash_slice
on each slice, but this
is wrong since the two slices can change with a call to
make_contiguous
without affecting the PartialEq
result. Since these slices aren’t treated as singular
units, and instead part of a larger deque, this method cannot
be used.
§Examples
use std::hash::{DefaultHasher, Hash, Hasher};
let mut hasher = DefaultHasher::new();
let numbers = [6, 28, 496, 8128];
Hash::hash_slice(&numbers, &mut hasher);
println!("Hash is {:x}!", hasher.finish());
Object Safety§
Implementors§
impl Hash for PadMode
impl Hash for AxisOp
impl Hash for InOut
impl Hash for KernelFormat
impl Hash for PaddingSpec
impl Hash for Cost
impl Hash for Validation
impl Hash for DataFormat
impl Hash for Reducer
impl Hash for SoftmaxExp
impl Hash for InputMapping
impl Hash for DatumType
impl Hash for QParams
impl Hash for TDim
impl Hash for AsciiChar
impl Hash for core::cmp::Ordering
impl Hash for Infallible
impl Hash for IpAddr
impl Hash for Ipv6MulticastScope
impl Hash for SocketAddr
impl Hash for core::sync::atomic::Ordering
impl Hash for std::io::error::ErrorKind
impl Hash for Level
impl Hash for LevelFilter
impl Hash for nom::error::ErrorKind
impl Hash for BinOp
impl Hash for RoundingPolicy
impl Hash for OutputStoreSpec
impl Hash for SliceInfoElem
impl Hash for bool
impl Hash for char
impl Hash for i8
impl Hash for i16
impl Hash for i32
impl Hash for i64
impl Hash for i128
impl Hash for isize
impl Hash for !
impl Hash for str
impl Hash for u8
impl Hash for u16
impl Hash for u32
impl Hash for u64
impl Hash for u128
impl Hash for ()
impl Hash for usize
impl Hash for AxesMapping
impl Hash for tract_core::axes::Axis
impl Hash for InletId
impl Hash for OutletId
impl Hash for ShapeFact
impl Hash for TypedFact
impl Hash for DynSlice
impl Hash for StridedSlice
impl Hash for FiniteReshape
impl Hash for Gather
impl Hash for GatherElements
impl Hash for GatherNd
impl Hash for MultiBroadcastTo
impl Hash for OneHot
impl Hash for Pad
impl Hash for tract_core::ops::array::Range
impl Hash for ScatterElements
impl Hash for ScatterNd
impl Hash for tract_core::ops::array::Slice
impl Hash for Tile
impl Hash for Topk
impl Hash for TypedConcat
impl Hash for Cast
impl Hash for AxisChange
impl Hash for Conv
impl Hash for Im2Col
impl Hash for Deconv
impl Hash for ConcretePoolGeometry
impl Hash for PoolSpec
impl Hash for SymbolicPoolGeometry
impl Hash for MaxPool
impl Hash for Patch
impl Hash for PatchSpec
impl Hash for SumPool
impl Hash for Downsample
impl Hash for Dummy
impl Hash for EinSum
impl Hash for Fft
impl Hash for Stft
impl Hash for Identity
impl Hash for Const
impl Hash for And
impl Hash for BitAnd
impl Hash for BitOr
impl Hash for BitXor
impl Hash for Equals
impl Hash for Greater
impl Hash for GreaterEqual
impl Hash for Iff
impl Hash for Less
impl Hash for LessEqual
impl Hash for NotEquals
impl Hash for Or
impl Hash for Xor
impl Hash for Add
impl Hash for Div
impl Hash for Max
impl Hash for Min
impl Hash for Mul
impl Hash for Pow
impl Hash for Rem
impl Hash for ShiftLeft
impl Hash for ShiftRight
impl Hash for Sub
impl Hash for ConcreteMatrixGeometry
impl Hash for SymbolicMatrixGeometry
impl Hash for MatMatMulPack
impl Hash for Reduce
impl Hash for Softmax
impl Hash for Scale
impl Hash for ScanInfo
impl Hash for TypedSource
impl Hash for UnimplementedOp
impl Hash for TypeId
impl Hash for CStr
impl Hash for PhantomPinned
impl Hash for Ipv4Addr
impl Hash for Ipv6Addr
impl Hash for SocketAddrV4
impl Hash for SocketAddrV6
impl Hash for RangeFull
impl Hash for Alignment
impl Hash for Duration
impl Hash for OsStr
impl Hash for OsString
impl Hash for FileType
impl Hash for UCred
impl Hash for Path
impl Hash for PathBuf
impl Hash for PrefixComponent<'_>
impl Hash for ThreadId
impl Hash for Instant
impl Hash for SystemTime
impl Hash for aho_corasick::util::primitives::PatternID
impl Hash for aho_corasick::util::primitives::StateID
impl Hash for aho_corasick::util::search::Match
impl Hash for aho_corasick::util::search::Span
impl Hash for LazyStateID
impl Hash for Transition
impl Hash for NonMaxUsize
impl Hash for regex_automata::util::primitives::PatternID
impl Hash for SmallIndex
impl Hash for regex_automata::util::primitives::StateID
impl Hash for HalfMatch
impl Hash for regex_automata::util::search::Match
impl Hash for regex_automata::util::search::Span
impl Hash for SymbolU16
impl Hash for SymbolU32
impl Hash for SymbolUsize
impl Hash for EagerPackedInput
impl Hash for Packer
impl Hash for GenericLut8
impl Hash for Scaler
impl Hash for Blob
impl Hash for Opaque
impl Hash for Symbol
impl Hash for SymbolTable
impl Hash for Tensor
impl Hash for tract_core::internal::tract_ndarray::Axis
impl Hash for IxDynImpl
impl Hash for tract_core::internal::tract_ndarray::Slice
impl Hash for Layout
impl Hash for Box<dyn MatMatMul>
impl Hash for CString
impl Hash for Error
impl Hash for String
impl<'a> Hash for Component<'a>
impl<'a> Hash for Prefix<'a>
impl<'a> Hash for Location<'a>
impl<'a> Hash for Metadata<'a>
impl<'a> Hash for MetadataBuilder<'a>
impl<'hash> Hash for dyn DynHash + 'hash
impl<'hash> Hash for dyn DynHash + Send + 'hash
impl<'hash> Hash for dyn DynHash + Send + Sync + 'hash
impl<'hash> Hash for dyn DynHash + Sync + 'hash
impl<'hash> Hash for dyn MMMInput + 'hash
impl<'hash> Hash for dyn MMMInput + Send + 'hash
impl<'hash> Hash for dyn MMMInput + Send + Sync + 'hash
impl<'hash> Hash for dyn MMMInput + Sync + 'hash
impl<'hash> Hash for dyn OpaquePayload + 'hash
impl<'hash> Hash for dyn OpaquePayload + Send + 'hash
impl<'hash> Hash for dyn OpaquePayload + Send + Sync + 'hash
impl<'hash> Hash for dyn OpaquePayload + Sync + 'hash
impl<A> Hash for SmallVec<A>
impl<A, B> Hash for EitherOrBoth<A, B>
impl<B> Hash for Cow<'_, B>
impl<B> Hash for BitSet<B>where
B: BitBlock,
impl<B> Hash for BitVec<B>where
B: BitBlock,
impl<B, C> Hash for ControlFlow<B, C>
impl<D, S> Hash for BaseDataShape<D, S>
impl<Dyn> Hash for DynMetadata<Dyn>where
Dyn: ?Sized,
impl<F> Hash for Fwhere
F: FnPtr,
impl<F: Hash + Clone> Hash for OutputMapping<F>
impl<I> Hash for Dim<I>
impl<Idx> Hash for core::ops::range::Range<Idx>where
Idx: Hash,
impl<Idx> Hash for RangeFrom<Idx>where
Idx: Hash,
impl<Idx> Hash for RangeInclusive<Idx>where
Idx: Hash,
impl<Idx> Hash for RangeTo<Idx>where
Idx: Hash,
impl<Idx> Hash for RangeToInclusive<Idx>where
Idx: Hash,
impl<K> Hash for LutImpl<K>
impl<K, V, A> Hash for BTreeMap<K, V, A>
impl<L, R> Hash for Either<L, R>
impl<Ptr> Hash for Pin<Ptr>
impl<S, D> Hash for ArrayBase<S, D>
impl<Symbolic: Hash, Concrete: Hash> Hash for GeometryBound<Symbolic, Concrete>
impl<T> Hash for Bound<T>where
T: Hash,
impl<T> Hash for Option<T>where
T: Hash,
impl<T> Hash for Poll<T>where
T: Hash,
impl<T> Hash for *const Twhere
T: ?Sized,
impl<T> Hash for *mut Twhere
T: ?Sized,
impl<T> Hash for &T
impl<T> Hash for &mut T
impl<T> Hash for [T]where
T: Hash,
impl<T> Hash for (T₁, T₂, …, Tₙ)
This trait is implemented for tuples up to twelve items long.
impl<T> Hash for Reverse<T>where
T: Hash,
impl<T> Hash for ManuallyDrop<T>
impl<T> Hash for Discriminant<T>
impl<T> Hash for NonZero<T>where
T: ZeroablePrimitive + Hash,
impl<T> Hash for Saturating<T>where
T: Hash,
impl<T> Hash for Wrapping<T>where
T: Hash,
impl<T> Hash for NonNull<T>where
T: ?Sized,
impl<T> Hash for Complex<T>where
T: Hash,
impl<T> Hash for Unalign<T>
impl<T> Hash for PhantomData<T>where
T: ?Sized,
impl<T, A> Hash for Box<T, A>
impl<T, A> Hash for BTreeSet<T, A>
impl<T, A> Hash for LinkedList<T, A>
impl<T, A> Hash for VecDeque<T, A>
impl<T, A> Hash for Rc<T, A>
impl<T, A> Hash for Arc<T, A>
impl<T, A> Hash for Vec<T, A>
The hash of a vector is the same as that of the corresponding slice,
as required by the core::borrow::Borrow
implementation.
use std::hash::BuildHasher;
let b = std::hash::RandomState::new();
let v: Vec<u8> = vec![0xa8, 0x3c, 0x09];
let s: &[u8] = &[0xa8, 0x3c, 0x09];
assert_eq!(b.hash_one(v), b.hash_one(s));
impl<T, E> Hash for Result<T, E>
impl<T, const N: usize> Hash for [T; N]where
T: Hash,
The hash of an array is the same as that of the corresponding slice,
as required by the Borrow
implementation.
use std::hash::BuildHasher;
let b = std::hash::RandomState::new();
let a: [u8; 3] = [0xa8, 0x3c, 0x09];
let s: &[u8] = &[0xa8, 0x3c, 0x09];
assert_eq!(b.hash_one(a), b.hash_one(s));