Struct diem_crypto::hash::HashValue

pub struct HashValue { /* private fields */ }

Output value of our hash function. Intentionally opaque for safety and modularity.

Implementations

impl HashValue

pub const LENGTH: usize = 32usize

The length of the hash in bytes.

pub const LENGTH_IN_BITS: usize = 256usize

The length of the hash in bits.

pub fn new(hash: [u8; 32]) -> Self

Create a new HashValue from a byte array.

pub fn from_slice<T: AsRef<[u8]>>(bytes: T) -> Result<Self, HashValueParseError>

Create from a slice (e.g. retrieved from storage).

pub fn to_vec(&self) -> Vec<u8>

Dumps into a vector.

pub const fn zero() -> Self

Creates a zero-initialized instance.

pub fn random() -> Self

Create a cryptographically random instance.

pub fn random_with_rng<R: Rng>(rng: &mut R) -> Self

Creates a random instance with given rng. Useful in unit tests.

pub fn sha3_256_of(buffer: &[u8]) -> Self

Convenience function that computes a HashValue internally equal to the sha3_256 of a byte buffer. It will handle hasher creation, data feeding and finalization.

Note this will not result in the <T as CryptoHash>::hash() for any reasonable struct T, as this computes a sha3 without any ornaments.

pub fn iter_bits(&self) -> HashValueBitIterator<'_>

Returns a HashValueBitIterator over all the bits that represent this HashValue.

pub fn from_bit_iter( iter: impl ExactSizeIterator<Item = bool> ) -> Result<Self, HashValueParseError>

Constructs a HashValue from an iterator of bits.

pub fn common_prefix_bits_len(&self, other: HashValue) -> usize

Returns the length of common prefix of self and other in bits.

pub fn to_hex(&self) -> String

Full hex representation of a given hash value.

pub fn from_hex<T: AsRef<[u8]>>(hex: T) -> Result<Self, HashValueParseError>

Parse a given hex string to a hash value.

pub fn to_u256(&self) -> U256

Convert a hash to big int (U256).

Methods from Deref<Target = [u8; 32]>

pub fn as_ascii(&self) -> Option<&[AsciiChar; N]>

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

Converts this array of bytes into a array of ASCII characters, or returns None if any of the characters is non-ASCII.

Examples

#![feature(ascii_char)]
#![feature(const_option)]

const HEX_DIGITS: [std::ascii::Char; 16] =
    *b"0123456789abcdef".as_ascii().unwrap();

assert_eq!(HEX_DIGITS[1].as_str(), "1");
assert_eq!(HEX_DIGITS[10].as_str(), "a");

pub unsafe fn as_ascii_unchecked(&self) -> &[AsciiChar; N]

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

Converts this array of bytes into a array of ASCII characters, without checking whether they’re valid.

Safety

Every byte in the array must be in 0..=127, or else this is UB.

pub fn as_slice(&self) -> &[T]

Returns a slice containing the entire array. Equivalent to &s[..].

pub fn each_ref(&self) -> [&T; N]

Borrows each element and returns an array of references with the same size as self.

Example

let floats = [3.1, 2.7, -1.0];
let float_refs: [&f64; 3] = floats.each_ref();
assert_eq!(float_refs, [&3.1, &2.7, &-1.0]);

This method is particularly useful if combined with other methods, like map. This way, you can avoid moving the original array if its elements are not Copy.

let strings = ["Ferris".to_string(), "♥".to_string(), "Rust".to_string()];
let is_ascii = strings.each_ref().map(|s| s.is_ascii());
assert_eq!(is_ascii, [true, false, true]);

// We can still access the original array: it has not been moved.
assert_eq!(strings.len(), 3);

pub fn split_array_ref<const M: usize>(&self) -> (&[T; M], &[T])

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

Divides one array reference into two at an index.

The first will contain all indices from [0, M) (excluding the index M itself) and the second will contain all indices from [M, N) (excluding the index N itself).

Panics

Panics if M > N.

Examples

#![feature(split_array)]

let v = [1, 2, 3, 4, 5, 6];

{
   let (left, right) = v.split_array_ref::<0>();
   assert_eq!(left, &[]);
   assert_eq!(right, &[1, 2, 3, 4, 5, 6]);
}

{
    let (left, right) = v.split_array_ref::<2>();
    assert_eq!(left, &[1, 2]);
    assert_eq!(right, &[3, 4, 5, 6]);
}

{
    let (left, right) = v.split_array_ref::<6>();
    assert_eq!(left, &[1, 2, 3, 4, 5, 6]);
    assert_eq!(right, &[]);
}

pub fn rsplit_array_ref<const M: usize>(&self) -> (&[T], &[T; M])

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

Divides one array reference into two at an index from the end.

The first will contain all indices from [0, N - M) (excluding the index N - M itself) and the second will contain all indices from [N - M, N) (excluding the index N itself).

Panics

Panics if M > N.

Examples

#![feature(split_array)]

let v = [1, 2, 3, 4, 5, 6];

{
   let (left, right) = v.rsplit_array_ref::<0>();
   assert_eq!(left, &[1, 2, 3, 4, 5, 6]);
   assert_eq!(right, &[]);
}

{
    let (left, right) = v.rsplit_array_ref::<2>();
    assert_eq!(left, &[1, 2, 3, 4]);
    assert_eq!(right, &[5, 6]);
}

{
    let (left, right) = v.rsplit_array_ref::<6>();
    assert_eq!(left, &[]);
    assert_eq!(right, &[1, 2, 3, 4, 5, 6]);
}

Trait Implementations

impl AsRef<[u8; 32]> for HashValue

fn as_ref(&self) -> &[u8; 32]

Converts this type into a shared reference of the (usually inferred) input type.

impl Binary for HashValue

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

Formats the value using the given formatter.

impl Clone for HashValue

fn clone(&self) -> HashValue

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for HashValue

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

Formats the value using the given formatter.

impl Default for HashValue

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for HashValue

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for HashValue

Will print shortened (4 bytes) hash

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

Formats the value using the given formatter.

impl From<HashValue> for Bytes

fn from(value: HashValue) -> Bytes

Converts to this type from the input type.

impl FromStr for HashValue

type Err = HashValueParseError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, HashValueParseError>

Parses a string s to return a value of this type.

impl Hash for HashValue

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

Feeds this value into the given Hasher.

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

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Index<usize> for HashValue

type Output = u8

The returned type after indexing.

fn index(&self, s: usize) -> &u8

Performs the indexing (container[index]) operation.

impl LowerHex for HashValue

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

Formats the value using the given formatter.

impl Ord for HashValue

fn cmp(&self, other: &HashValue) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for HashValue

fn eq(&self, other: &HashValue) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl PartialOrd for HashValue

fn partial_cmp(&self, other: &HashValue) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for HashValue

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl Deref for HashValue

type Target = [u8; 32]

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Copy for HashValue

impl Eq for HashValue

impl StructuralPartialEq for HashValue