Trait kvarn::prelude::utils::prelude::compact_str::core::hash::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 hashed 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§

1.0.0 · source

fn hash<H>(&self, state: &mut H)
where H: Hasher,

Feeds this value into the given Hasher.

§Examples
use std::hash::{DefaultHasher, Hash, Hasher};

let mut hasher = DefaultHasher::new();
7920.hash(&mut hasher);
println!("Hash is {:x}!", hasher.finish());

Provided Methods§

1.3.0 · source

fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

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§

This trait is not object safe.

Implementors§

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impl Hash for CachePreferenceError

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impl Hash for ClientCachePreference

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impl Hash for CompressPreference

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impl Hash for ServerCachePreference

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impl Hash for UriKey

1.7.0 · source§

impl Hash for kvarn::prelude::IpAddr

1.0.0 · source§

impl Hash for SocketAddr

1.0.0 · source§

impl Hash for kvarn::prelude::utils::prelude::io::ErrorKind

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impl Hash for Ipv6MulticastScope

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impl Hash for AsciiChar

1.0.0 · source§

impl Hash for kvarn::prelude::utils::prelude::compact_str::core::cmp::Ordering

1.44.0 · source§

impl Hash for Infallible

1.0.0 · source§

impl Hash for kvarn::prelude::utils::prelude::compact_str::core::sync::atomic::Ordering

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impl Hash for log::Level

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impl Hash for log::LevelFilter

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impl Hash for Direction

1.0.0 · source§

impl Hash for bool

1.0.0 · source§

impl Hash for char

1.0.0 · source§

impl Hash for i8

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impl Hash for i16

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impl Hash for i32

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impl Hash for i64

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impl Hash for i128

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impl Hash for isize

1.29.0 · source§

impl Hash for !

1.0.0 · source§

impl Hash for str

1.0.0 · source§

impl Hash for u8

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impl Hash for u16

1.0.0 · source§

impl Hash for u32

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impl Hash for u64

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impl Hash for u128

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impl Hash for ()

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impl Hash for usize

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impl Hash for PathQuery

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impl Hash for OffsetDateTime

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impl Hash for Mime

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impl Hash for Bytes

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impl Hash for BytesMut

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impl Hash for CompactString

1.3.0 · source§

impl Hash for kvarn::prelude::Duration

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impl Hash for HeaderName

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impl Hash for HeaderValue

1.8.0 · source§

impl Hash for kvarn::prelude::Instant

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impl Hash for Method

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impl Hash for Path

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impl Hash for PathBuf

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impl Hash for StatusCode

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impl Hash for Uri

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impl Hash for Version

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impl Hash for kvarn::prelude::utils::prelude::fmt::Error

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impl Hash for kvarn::prelude::utils::prelude::net::Ipv4Addr

1.0.0 · source§

impl Hash for kvarn::prelude::utils::prelude::net::Ipv6Addr

1.0.0 · source§

impl Hash for SocketAddrV4

1.0.0 · source§

impl Hash for SocketAddrV6

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impl Hash for Authority

Case-insensitive hashing

§Examples


let a: Authority = "HELLO.com".parse().unwrap();
let b: Authority = "hello.coM".parse().unwrap();

let mut s = DefaultHasher::new();
a.hash(&mut s);
let a = s.finish();

let mut s = DefaultHasher::new();
b.hash(&mut s);
let b = s.finish();

assert_eq!(a, b);
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impl Hash for PathAndQuery

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impl Hash for Scheme

Case-insensitive hashing

1.28.0 · source§

impl Hash for Layout

1.0.0 · source§

impl Hash for TypeId

1.64.0 · source§

impl Hash for CStr

1.33.0 · source§

impl Hash for PhantomPinned

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impl Hash for RangeFull

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impl Hash for Alignment

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impl Hash for CString

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impl Hash for String

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impl Hash for OsStr

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impl Hash for OsString

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impl Hash for FileType

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impl Hash for std::os::unix::net::ucred::UCred

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impl Hash for PrefixComponent<'_>

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impl Hash for ThreadId

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impl Hash for SystemTime

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impl Hash for FixedBitSet

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impl Hash for petgraph::visit::dfsvisit::Time

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impl Hash for ATerm

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impl Hash for B0

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impl Hash for B1

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impl Hash for Z0

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impl Hash for Equal

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impl Hash for Greater

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impl Hash for Less

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impl Hash for UTerm

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impl Hash for uuid::error::Error

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impl Hash for Braced

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impl Hash for Hyphenated

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impl Hash for Simple

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impl Hash for Urn

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impl Hash for Uuid

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impl Hash for Timestamp

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impl Hash for AccessKind

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impl Hash for AccessMode

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impl Hash for AnyDelimiterCodec

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impl Hash for BigEndian

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impl Hash for BytesCodec

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impl Hash for Code

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impl Hash for ComponentRange

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impl Hash for CompressionLevel

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impl Hash for CompressionStrategy

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impl Hash for Config

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impl Hash for ConnectionHandle

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impl Hash for ConnectionId

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impl Hash for CreateKind

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impl Hash for DataChange

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impl Hash for DataFormat

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impl Hash for Date

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impl Hash for Dir

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impl Hash for Duration

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impl Hash for ErrorKind

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impl Hash for ErrorLevel

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impl Hash for Event

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impl Hash for EventKind

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impl Hash for EventMask

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impl Hash for Field

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impl Hash for FileTime

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impl Hash for Flag

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impl Hash for Flags

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impl Hash for FsyncFlags

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impl Hash for Handle

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impl Hash for Id

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impl Hash for Identifier

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impl Hash for IdleTimeout

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impl Hash for Instant

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impl Hash for Instant

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impl Hash for IpAddr

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impl Hash for Ipv4Addr

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impl Hash for Ipv6Addr

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impl Hash for Level

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impl Hash for LevelFilter

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impl Hash for LinesCodec

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impl Hash for LiteralPredictionModeNibble

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impl Hash for LittleEndian

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impl Hash for MZError

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impl Hash for MZFlush

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impl Hash for MZStatus

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impl Hash for MetadataKind

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impl Hash for ModifyKind

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impl Hash for Month

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impl Hash for Null

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impl Hash for PacketDecodeError

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impl Hash for PollNext

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impl Hash for PrimitiveDateTime

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impl Hash for ReadError

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impl Hash for ReadableError

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impl Hash for RecursiveMode

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impl Hash for RemoveKind

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impl Hash for RenameMode

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impl Hash for SendDatagramError

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impl Hash for Side

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impl Hash for SockAddr

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impl Hash for Span

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impl Hash for StreamId

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impl Hash for StreamId

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impl Hash for StreamId

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impl Hash for StreamResult

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impl Hash for TDEFLFlush

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impl Hash for TDEFLStatus

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impl Hash for TINFLStatus

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impl Hash for Time

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impl Hash for TimeoutFlags

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impl Hash for Token

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impl Hash for UCred

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impl Hash for UtcOffset

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impl Hash for VarInt

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impl Hash for WatchDescriptor

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impl Hash for WatchMask

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impl Hash for WatcherKind

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impl Hash for Weekday

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impl Hash for WriteError

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impl Hash for ZSTD_EndDirective

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impl Hash for ZSTD_ResetDirective

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impl Hash for ZSTD_cParameter

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impl Hash for ZSTD_dParameter

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impl Hash for ZSTD_strategy

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impl Hash for point_conversion_form_t

1.0.0 · source§

impl<'a> Hash for Component<'a>

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impl<'a> Hash for Prefix<'a>

1.10.0 · source§

impl<'a> Hash for Location<'a>

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impl<'a> Hash for Metadata<'a>

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impl<'a> Hash for MetadataBuilder<'a>

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impl<'a> Hash for Name<'a>

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impl<'a> Hash for DnsName<'a>

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impl<'a> Hash for ServerName<'a>

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impl<'b, T> Hash for Ptr<'b, T>

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impl<'s, T> Hash for SliceVec<'s, T>
where T: Hash,

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impl<A> Hash for ArrayVec<A>
where A: Array, <A as Array>::Item: Hash,

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impl<A> Hash for SmallVec<A>
where A: Array, <A as Array>::Item: Hash,

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impl<A> Hash for TinyVec<A>
where A: Array, <A as Array>::Item: Hash,

1.0.0 · source§

impl<B> Hash for Cow<'_, B>
where B: Hash + ToOwned + ?Sized,

1.55.0 · source§

impl<B, C> Hash for ControlFlow<B, C>
where B: Hash, C: Hash,

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impl<Dyn> Hash for DynMetadata<Dyn>
where Dyn: ?Sized,

1.4.0 · source§

impl<F> Hash for F
where F: FnPtr,

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impl<H> Hash for HeaderWithLength<H>
where H: Hash,

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impl<H, T> Hash for HeaderSlice<H, T>
where H: Hash, T: Hash + ?Sized,

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impl<H, T> Hash for ThinArc<H, T>
where H: Hash, T: Hash,

1.0.0 · source§

impl<Idx> Hash for Range<Idx>
where Idx: Hash,

1.0.0 · source§

impl<Idx> Hash for RangeFrom<Idx>
where Idx: Hash,

1.26.0 · source§

impl<Idx> Hash for RangeInclusive<Idx>
where Idx: Hash,

1.0.0 · source§

impl<Idx> Hash for RangeTo<Idx>
where Idx: Hash,

1.26.0 · source§

impl<Idx> Hash for RangeToInclusive<Idx>
where Idx: Hash,

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impl<Ix> Hash for petgraph::adj::EdgeIndex<Ix>
where Ix: Hash + IndexType,

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impl<Ix> Hash for petgraph::graph_impl::EdgeIndex<Ix>
where Ix: Hash,

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impl<Ix> Hash for NodeIndex<Ix>
where Ix: Hash,

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impl<K, V> Hash for Slice<K, V>
where K: Hash, V: Hash,

1.0.0 · source§

impl<K, V, A> Hash for BTreeMap<K, V, A>
where K: Hash, V: Hash, A: Allocator + Clone,

1.41.0 · source§

impl<Ptr> Hash for Pin<Ptr>
where Ptr: Deref, <Ptr as Deref>::Target: Hash,

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impl<S> Hash for Ascii<S>
where S: AsRef<str>,

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impl<S> Hash for UniCase<S>
where S: AsRef<str>,

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impl<Storage> Hash for __BindgenBitfieldUnit<Storage>
where Storage: Hash,

1.36.0 · source§

impl<T> Hash for Poll<T>
where T: Hash,

1.17.0 · source§

impl<T> Hash for Bound<T>
where T: Hash,

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impl<T> Hash for Option<T>
where T: Hash,

1.0.0 · source§

impl<T> Hash for *const T
where T: ?Sized,

1.0.0 · source§

impl<T> Hash for *mut T
where T: ?Sized,

1.0.0 · source§

impl<T> Hash for &T
where T: Hash + ?Sized,

1.0.0 · source§

impl<T> Hash for &mut T
where T: Hash + ?Sized,

1.0.0 · source§

impl<T> Hash for [T]
where T: Hash,

1.0.0 · source§

impl<T> Hash for (T₁, T₂, …, Tₙ)
where T: Hash + ?Sized,

This trait is implemented for tuples up to twelve items long.

1.19.0 · source§

impl<T> Hash for Reverse<T>
where T: Hash,

1.0.0 · source§

impl<T> Hash for PhantomData<T>
where T: ?Sized,

1.21.0 · source§

impl<T> Hash for Discriminant<T>

1.20.0 · source§

impl<T> Hash for ManuallyDrop<T>
where T: Hash + ?Sized,

1.28.0 · source§

impl<T> Hash for NonZero<T>

1.74.0 · source§

impl<T> Hash for Saturating<T>
where T: Hash,

1.0.0 · source§

impl<T> Hash for Wrapping<T>
where T: Hash,

1.25.0 · source§

impl<T> Hash for NonNull<T>
where T: ?Sized,

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impl<T> Hash for AllowStdIo<T>
where T: Hash,

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impl<T> Hash for Arc<T>
where T: Hash + ?Sized,

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impl<T> Hash for CachePadded<T>
where T: Hash,

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impl<T> Hash for Slice<T>
where T: Hash,

1.0.0 · source§

impl<T, A> Hash for kvarn::prelude::Arc<T, A>
where T: Hash + ?Sized, A: Allocator,

1.0.0 · source§

impl<T, A> Hash for Box<T, A>
where T: Hash + ?Sized, A: Allocator,

1.0.0 · source§

impl<T, A> Hash for BTreeSet<T, A>
where T: Hash, A: Allocator + Clone,

1.0.0 · source§

impl<T, A> Hash for LinkedList<T, A>
where T: Hash, A: Allocator,

1.0.0 · source§

impl<T, A> Hash for VecDeque<T, A>
where T: Hash, A: Allocator,

1.0.0 · source§

impl<T, A> Hash for Rc<T, A>
where T: Hash + ?Sized, A: Allocator,

1.0.0 · source§

impl<T, A> Hash for Vec<T, A>
where T: Hash, A: Allocator,

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));
1.0.0 · source§

impl<T, E> Hash for Result<T, E>
where T: Hash, E: Hash,

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impl<T, N> Hash for GenericArray<T, N>
where T: Hash, N: ArrayLength<T>,

1.0.0 · source§

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));
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impl<T, const N: usize> Hash for Simd<T, N>

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impl<T, const N: usize> Hash for TagNonNull<T, N>

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impl<T, const N: usize> Hash for TagPtr<T, N>

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impl<U> Hash for NInt<U>
where U: Hash + Unsigned + NonZero,

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impl<U> Hash for PInt<U>
where U: Hash + Unsigned + NonZero,

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impl<U, B> Hash for UInt<U, B>
where U: Hash, B: Hash,

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impl<V, A> Hash for TArr<V, A>
where V: Hash, A: Hash,

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impl<V: Hash> Hash for CacheOut<V>

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impl<Y, R> Hash for CoroutineState<Y, R>
where Y: Hash, R: Hash,

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impl<const MIN: i8, const MAX: i8> Hash for OptionRangedI8<MIN, MAX>

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impl<const MIN: i8, const MAX: i8> Hash for RangedI8<MIN, MAX>

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impl<const MIN: i16, const MAX: i16> Hash for OptionRangedI16<MIN, MAX>

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impl<const MIN: i16, const MAX: i16> Hash for RangedI16<MIN, MAX>

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impl<const MIN: i32, const MAX: i32> Hash for OptionRangedI32<MIN, MAX>

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impl<const MIN: i32, const MAX: i32> Hash for RangedI32<MIN, MAX>

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impl<const MIN: i64, const MAX: i64> Hash for OptionRangedI64<MIN, MAX>

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impl<const MIN: i64, const MAX: i64> Hash for RangedI64<MIN, MAX>

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impl<const MIN: i128, const MAX: i128> Hash for OptionRangedI128<MIN, MAX>

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impl<const MIN: i128, const MAX: i128> Hash for RangedI128<MIN, MAX>

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impl<const MIN: isize, const MAX: isize> Hash for OptionRangedIsize<MIN, MAX>

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impl<const MIN: isize, const MAX: isize> Hash for RangedIsize<MIN, MAX>

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impl<const MIN: u8, const MAX: u8> Hash for OptionRangedU8<MIN, MAX>

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impl<const MIN: u8, const MAX: u8> Hash for RangedU8<MIN, MAX>

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impl<const MIN: u16, const MAX: u16> Hash for OptionRangedU16<MIN, MAX>

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impl<const MIN: u16, const MAX: u16> Hash for RangedU16<MIN, MAX>

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impl<const MIN: u32, const MAX: u32> Hash for OptionRangedU32<MIN, MAX>

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impl<const MIN: u32, const MAX: u32> Hash for RangedU32<MIN, MAX>

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impl<const MIN: u64, const MAX: u64> Hash for OptionRangedU64<MIN, MAX>

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impl<const MIN: u64, const MAX: u64> Hash for RangedU64<MIN, MAX>

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impl<const MIN: u128, const MAX: u128> Hash for OptionRangedU128<MIN, MAX>

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impl<const MIN: u128, const MAX: u128> Hash for RangedU128<MIN, MAX>

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impl<const MIN: usize, const MAX: usize> Hash for OptionRangedUsize<MIN, MAX>

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impl<const MIN: usize, const MAX: usize> Hash for RangedUsize<MIN, MAX>

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impl<const SIZE: usize> Hash for WriteBuffer<SIZE>