Struct CtByteArray

pub struct CtByteArray<const N: usize>(/* private fields */);

A byte array of length N for which comparisons are performed in constant time.

Limitations

It is possible to avoid constant time comparisons here, just by using the as_ref() and as_mut() methods. They should therefore be approached with some caution.

(The decision to avoid implementing Deref/DerefMut is deliberate.)

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

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

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

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

Examples

#![feature(ascii_char)]

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 an 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<const N: usize> AsMut<[u8; N]> for CtByteArray<N>

fn as_mut(&mut self) -> &mut [u8; N]

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

impl<const N: usize> AsRef<[u8; N]> for CtByteArray<N>

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

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

impl<const N: usize> Clone for CtByteArray<N>

fn clone(&self) -> CtByteArray<N>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<const N: usize> ConstantTimeEq for CtByteArray<N>

fn ct_eq(&self, other: &Self) -> Choice

Determine if two items are equal.

fn ct_ne(&self, other: &Self) -> Choice

Determine if two items are NOT equal.

impl<const N: usize> Debug for CtByteArray<N>

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

Formats the value using the given formatter.

impl<const N: usize> Deref for CtByteArray<N>

type Target = [u8; N]

The resulting type after dereferencing.

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

Dereferences the value.

impl<const N: usize> From<[u8; N]> for CtByteArray<N>

fn from(value: [u8; N]) -> Self

Converts to this type from the input type.

impl<const N: usize> From<CtByteArray<N>> for [u8; N]

fn from(value: CtByteArray<N>) -> Self

Converts to this type from the input type.

impl<const N: usize> HasMemoryCostStructural for CtByteArray<N>

fn indirect_memory_cost(&self, et: EnabledToken) -> usize

Memory cost of data stored out-of-line

impl<const N: usize> Hash for CtByteArray<N>

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<const N: usize> Ord for CtByteArray<N>

fn cmp(&self, other: &Self) -> 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,

Restrict a value to a certain interval.

impl<const N: usize> PartialEq for CtByteArray<N>

fn eq(&self, other: &Self) -> 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<const N: usize> PartialOrd for CtByteArray<N>

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

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

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

Tests less than (for self and other) and is used by the < operator.

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

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

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

Tests greater than (for self and other) and is used by the > operator.

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

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

impl<const N: usize> Zeroize for CtByteArray<N>

fn zeroize(&mut self)

Zero out this object from memory using Rust intrinsics which ensure the zeroization operation is not “optimized away” by the compiler.

impl<const N: usize> Copy for CtByteArray<N>

impl<const N: usize> Eq for CtByteArray<N>