Struct Limb

#[repr(transparent)]
pub struct Limb(pub Word);

Big integers are represented as an array/vector of smaller CPU word-size integers called “limbs”.

The Limb type uses a 32-bit or 64-bit saturated representation, depending on the target. All bits of an inner Word are used to represent larger big integer types.

Tuple Fields

0: Word

Implementations

impl Limb

pub const fn overflowing_add(self, rhs: Limb) -> (Limb, Limb)

Computes self + rhs, returning the result along with the carry.

pub const fn adc(self, rhs: Limb, carry: Limb) -> (Limb, Limb)

Computes self + rhs + carry, returning the result along with the new carry.

pub const fn saturating_add(&self, rhs: Self) -> Self

Perform saturating addition.

pub const fn wrapping_add(&self, rhs: Self) -> Self

Perform wrapping addition, discarding overflow.

impl Limb

pub const fn bitand(self, rhs: Self) -> Self

Calculates a & b.

impl Limb

pub const fn not(self) -> Self

Calculates !a.

impl Limb

pub const fn bitor(self, rhs: Self) -> Self

Calculates a | b.

impl Limb

pub const fn bitxor(self, rhs: Self) -> Self

Calculates a ^ b.

impl Limb

pub const fn bits(self) -> u32

Calculate the number of bits needed to represent this number.

pub const fn leading_zeros(self) -> u32

Calculate the number of leading zeros in the binary representation of this number.

pub const fn trailing_zeros(self) -> u32

Calculate the number of trailing zeros in the binary representation of this number.

pub const fn trailing_ones(self) -> u32

Calculate the number of trailing ones the binary representation of this number.

impl Limb

pub fn is_odd(&self) -> Choice

Is this limb an odd number?

pub fn cmp_vartime(&self, other: &Self) -> Ordering

Perform a comparison of the inner value in variable-time.

Note that the PartialOrd and Ord impls wrap constant-time comparisons using the subtle crate.

pub const fn eq_vartime(&self, other: &Self) -> bool

Performs an equality check in variable-time.

impl Limb

pub const fn from_u8(n: u8) -> Self

Create a Limb from a u8 integer (const-friendly)

pub const fn from_u16(n: u16) -> Self

Create a Limb from a u16 integer (const-friendly)

pub const fn from_u32(n: u32) -> Self

Create a Limb from a u32 integer (const-friendly)

impl Limb

pub const fn mac(self, b: Limb, c: Limb, carry: Limb) -> (Limb, Limb)

Computes self + (b * c) + carry, returning the result along with the new carry.

pub const fn saturating_mul(&self, rhs: Self) -> Self

Perform saturating multiplication.

pub const fn wrapping_mul(&self, rhs: Self) -> Self

Perform wrapping multiplication, discarding overflow.

impl Limb

pub const fn wrapping_neg(self) -> Self

Perform wrapping negation.

impl Limb

pub const fn shl(self, shift: u32) -> Self

Computes self << shift. Panics if shift overflows Limb::BITS.

impl Limb

pub const fn shr(self, shift: u32) -> Self

Computes self >> shift. Panics if shift overflows Limb::BITS.

impl Limb

pub const fn sbb(self, rhs: Limb, borrow: Limb) -> (Limb, Limb)

Computes self - (rhs + borrow), returning the result along with the new borrow.

pub const fn saturating_sub(&self, rhs: Self) -> Self

Perform saturating subtraction.

pub const fn wrapping_sub(&self, rhs: Self) -> Self

Perform wrapping subtraction, discarding underflow and wrapping around the boundary of the type.

impl Limb

pub const ZERO: Self

The value 0.

pub const ONE: Self

The value 1.

pub const MAX: Self

Maximum value this Limb can express.

pub const BITS: u32 = 32u32

Available on 32-bit only.

Size of the inner integer in bits.

pub const BYTES: usize = 4usize

Available on 32-bit only.

Size of the inner integer in bytes.

pub const fn to_nz(self) -> ConstCtOption<NonZero<Self>>

Convert to a NonZero<Limb>.

Returns some if the original value is non-zero, and false otherwise.

Trait Implementations

impl Add for Limb

type Output = Limb

The resulting type after applying the + operator.

fn add(self, rhs: Self) -> Self

Performs the + operation.

impl Binary for Limb

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

Formats the value using the given formatter.

impl BitAnd for Limb

type Output = Limb

The resulting type after applying the & operator.

fn bitand(self, rhs: Self) -> Self::Output

Performs the & operation.

impl BitAndAssign<&Limb> for Limb

fn bitand_assign(&mut self, rhs: &Limb)

Performs the &= operation.

impl BitAndAssign for Limb

fn bitand_assign(&mut self, rhs: Self)

Performs the &= operation.

impl BitOr for Limb

type Output = Limb

The resulting type after applying the | operator.

fn bitor(self, rhs: Self) -> Self::Output

Performs the | operation.

impl BitOrAssign<&Limb> for Limb

fn bitor_assign(&mut self, other: &Self)

Performs the |= operation.

impl BitOrAssign for Limb

fn bitor_assign(&mut self, other: Self)

Performs the |= operation.

impl BitXor for Limb

type Output = Limb

The resulting type after applying the ^ operator.

fn bitxor(self, rhs: Self) -> Self::Output

Performs the ^ operation.

impl BitXorAssign for Limb

fn bitxor_assign(&mut self, rhs: Self)

Performs the ^= operation.

impl Bounded for Limb

const BITS: u32 = 32u32

Size of this integer in bits.

const BYTES: usize = 4usize

Size of this integer in bytes.

impl CheckedAdd for Limb

fn checked_add(&self, rhs: &Self) -> CtOption<Self>

Perform checked addition, returning a CtOption which is_some only if the operation did not overflow.

impl CheckedMul for Limb

fn checked_mul(&self, rhs: &Self) -> CtOption<Self>

Perform checked multiplication, returning a CtOption which is_some only if the operation did not overflow.

impl CheckedSub for Limb

fn checked_sub(&self, rhs: &Self) -> CtOption<Self>

Perform checked subtraction, returning a CtOption which is_some only if the operation did not underflow.

impl Clone for Limb

fn clone(&self) -> Limb

Returns a copy of the value.

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

Performs copy-assignment from source.

impl ConditionallySelectable for Limb

fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self

Select a or b according to choice.

fn conditional_assign(&mut self, other: &Self, choice: Choice)

Conditionally assign other to self, according to choice.

fn conditional_swap(a: &mut Self, b: &mut Self, choice: Choice)

Conditionally swap self and other if choice == 1; otherwise, reassign both unto themselves.

impl ConstZero for Limb

const ZERO: Self = Self::ZERO

The additive identity element of Self, 0.

impl ConstantTimeEq for Limb

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 ConstantTimeGreater for Limb

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

Determine whether self > other.

impl ConstantTimeLess for Limb

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

Determine whether self < other.

impl Constants for Limb

const ONE: Self = Self::ONE

The value 1.

const MAX: Self = Self::MAX

Maximum value this integer can express.

impl Debug for Limb

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

Formats the value using the given formatter.

impl Default for Limb

fn default() -> Limb

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Limb

Available on crate feature serde only.

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

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for Limb

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

Formats the value using the given formatter.

impl Encoding for Limb

type Repr = [u8; 4]

Byte array representation.

fn from_be_bytes(bytes: Self::Repr) -> Self

Decode from big endian bytes.

fn from_le_bytes(bytes: Self::Repr) -> Self

Decode from little endian bytes.

fn to_be_bytes(&self) -> Self::Repr

Encode to big endian bytes.

fn to_le_bytes(&self) -> Self::Repr

Encode to little endian bytes.

impl From<Limb> for BoxedUint

Available on crate feature alloc only.

fn from(limb: Limb) -> Self

Converts to this type from the input type.

impl<const LIMBS: usize> From<Limb> for Uint<LIMBS>

fn from(limb: Limb) -> Self

Converts to this type from the input type.

impl From<Limb> for Word

fn from(limb: Limb) -> Word

Converts to this type from the input type.

impl From<Limb> for WideWord

fn from(limb: Limb) -> WideWord

Converts to this type from the input type.

impl From<u16> for Limb

fn from(n: u16) -> Limb

Converts to this type from the input type.

impl From<u32> for Limb

fn from(n: u32) -> Limb

Converts to this type from the input type.

impl From<u8> for Limb

fn from(n: u8) -> Limb

Converts to this type from the input type.

impl Hash for Limb

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 LowerHex for Limb

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

Formats the value using the given formatter.

impl Mul<&Limb> for &Limb

type Output = Limb

The resulting type after applying the * operator.

fn mul(self, rhs: &Limb) -> Self::Output

Performs the * operation.

impl Mul<&Limb> for Limb

type Output = Limb

The resulting type after applying the * operator.

fn mul(self, rhs: &Limb) -> Self

Performs the * operation.

impl Mul<Limb> for &Limb

type Output = Limb

The resulting type after applying the * operator.

fn mul(self, rhs: Limb) -> Self::Output

Performs the * operation.

impl Mul for Limb

type Output = Limb

The resulting type after applying the * operator.

fn mul(self, rhs: Limb) -> Self

Performs the * operation.

impl Not for Limb

type Output = Limb

The resulting type after applying the ! operator.

fn not(self) -> <Self as Not>::Output

Performs the unary ! operation.

impl One for Limb

fn one() -> Self

Returns the multiplicative identity element of Self, 1.

fn is_one(&self) -> bool

Returns true if self is equal to the multiplicative identity.

fn set_one(&mut self)

Sets self to the multiplicative identity element of Self, 1.

impl Ord for Limb

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 PartialEq for Limb

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 PartialOrd for Limb

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 Random for Limb

Available on crate feature rand_core only.

fn random(rng: &mut (impl RngCore + ?Sized)) -> Self

Generate a random value.

impl RandomMod for Limb

Available on crate feature rand_core only.

fn random_mod( rng: &mut (impl RngCore + ?Sized), modulus: &NonZero<Self>, ) -> Self

Generate a random number which is less than a given modulus.

impl Serialize for Limb

Available on crate feature serde only.

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

where S: Serializer,

Serialize this value into the given Serde serializer.

impl Shl<i32> for &Limb

type Output = Limb

The resulting type after applying the << operator.

fn shl(self, shift: i32) -> Limb

Performs the << operation.

impl Shl<i32> for Limb

type Output = Limb

The resulting type after applying the << operator.

fn shl(self, shift: i32) -> Limb

Performs the << operation.

impl Shl<u32> for &Limb

type Output = Limb

The resulting type after applying the << operator.

fn shl(self, shift: u32) -> Limb

Performs the << operation.

impl Shl<u32> for Limb

type Output = Limb

The resulting type after applying the << operator.

fn shl(self, shift: u32) -> Limb

Performs the << operation.

impl Shl<usize> for &Limb

type Output = Limb

The resulting type after applying the << operator.

fn shl(self, shift: usize) -> Limb

Performs the << operation.

impl Shl<usize> for Limb

type Output = Limb

The resulting type after applying the << operator.

fn shl(self, shift: usize) -> Limb

Performs the << operation.

impl ShlAssign<i32> for Limb

fn shl_assign(&mut self, shift: i32)

Performs the <<= operation.

impl ShlAssign<u32> for Limb

fn shl_assign(&mut self, shift: u32)

Performs the <<= operation.

impl ShlAssign<usize> for Limb

fn shl_assign(&mut self, shift: usize)

Performs the <<= operation.

impl Shr<i32> for &Limb

type Output = Limb

The resulting type after applying the >> operator.

fn shr(self, shift: i32) -> Limb

Performs the >> operation.

impl Shr<i32> for Limb

type Output = Limb

The resulting type after applying the >> operator.

fn shr(self, shift: i32) -> Limb

Performs the >> operation.

impl Shr<u32> for &Limb

type Output = Limb

The resulting type after applying the >> operator.

fn shr(self, shift: u32) -> Limb

Performs the >> operation.

impl Shr<u32> for Limb

type Output = Limb

The resulting type after applying the >> operator.

fn shr(self, shift: u32) -> Limb

Performs the >> operation.

impl Shr<usize> for &Limb

type Output = Limb

The resulting type after applying the >> operator.

fn shr(self, shift: usize) -> Limb

Performs the >> operation.

impl Shr<usize> for Limb

type Output = Limb

The resulting type after applying the >> operator.

fn shr(self, shift: usize) -> Limb

Performs the >> operation.

impl ShrAssign<i32> for Limb

fn shr_assign(&mut self, shift: i32)

Performs the >>= operation.

impl ShrAssign<u32> for Limb

fn shr_assign(&mut self, shift: u32)

Performs the >>= operation.

impl ShrAssign<usize> for Limb

fn shr_assign(&mut self, shift: usize)

Performs the >>= operation.

impl Sub<&Limb> for Limb

type Output = Limb

The resulting type after applying the - operator.

fn sub(self, rhs: &Self) -> Self

Performs the - operation.

impl Sub for Limb

type Output = Limb

The resulting type after applying the - operator.

fn sub(self, rhs: Self) -> Self

Performs the - operation.

impl UpperHex for Limb

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

Formats the value using the given formatter.

impl WrappingAdd for Limb

fn wrapping_add(&self, v: &Self) -> Self

Wrapping (modular) addition. Computes self + other, wrapping around at the boundary of the type.

impl WrappingMul for Limb

fn wrapping_mul(&self, v: &Self) -> Self

Wrapping (modular) multiplication. Computes self * other, wrapping around at the boundary of the type.

impl WrappingNeg for Limb

fn wrapping_neg(&self) -> Self

Wrapping (modular) negation. Computes -self, wrapping around at the boundary of the type.

impl WrappingShl for Limb

fn wrapping_shl(&self, shift: u32) -> Limb

Panic-free bitwise shift-left; yields self << mask(rhs), where mask removes any high order bits of rhs that would cause the shift to exceed the bitwidth of the type.

impl WrappingShr for Limb

fn wrapping_shr(&self, shift: u32) -> Limb

Panic-free bitwise shift-right; yields self >> mask(rhs), where mask removes any high order bits of rhs that would cause the shift to exceed the bitwidth of the type.

impl WrappingSub for Limb

fn wrapping_sub(&self, v: &Self) -> Self

Wrapping (modular) subtraction. Computes self - other, wrapping around at the boundary of the type.

impl Zero for Limb

fn zero() -> Self

Returns the additive identity element of Self, 0.

fn is_zero(&self) -> bool

Returns true if self is equal to the additive identity.

fn set_zero(&mut self)

Sets self to the additive identity element of Self, 0.

impl Copy for Limb

impl DefaultIsZeroes for Limb

Available on crate feature zeroize only.

impl Eq for Limb