Struct sp_runtime::biguint::BigUint

pub struct BigUint { /* private fields */ }

Expand description

Simple wrapper around an infinitely large integer, represented as limbs of Single.

Implementations§

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impl BigUint

pub fn with_capacity(size: usize) -> BigUint

Create a new instance with size limbs. This prevents any number with zero limbs to be created.

The behavior of the type is undefined with zero limbs.

pub fn from_limbs(limbs: &[u32]) -> BigUint

Raw constructor from custom limbs. If limbs is empty, Zero::zero() implementation is used.

pub fn len(&self) -> usize

Number of limbs.

pub fn get(&self, index: usize) -> u32

A naive getter for limb at index. Note that the order is lsb -> msb.

§Panics

This panics if index is out of range.

pub fn checked_get(&self, index: usize) -> Option<u32>

A naive getter for limb at index. Note that the order is lsb -> msb.

pub fn set(&mut self, index: usize, value: u32)

A naive setter for limb at index. Note that the order is lsb -> msb.

§Panics

This panics if index is out of range.

pub fn lsb(&self) -> u32

returns the least significant limb of the number.

§Panics

While the constructor of the type prevents this, this can panic if self has no digits.

pub fn msb(&self) -> u32

returns the most significant limb of the number.

§Panics

While the constructor of the type prevents this, this can panic if self has no digits.

pub fn lstrip(&mut self)

Strips zeros from the left side (the most significant limbs) of self, if any.

pub fn lpad(&mut self, size: usize)

Zero-pad self from left to reach size limbs. Will not make any difference if self is already bigger than size limbs.

pub fn add(self, other: &BigUint) -> BigUint

Adds self with other. self and other do not have to have any particular size. Given that the n = max{size(self), size(other)}, it will produce a number with n + 1 limbs.

This function does not strip the output and returns the original allocated n + 1 limbs. The caller may strip the output if desired.

Taken from “The Art of Computer Programming” by D.E. Knuth, vol 2, chapter 4.

pub fn sub(self, other: &BigUint) -> Result<BigUint, BigUint>

Subtracts other from self. self and other do not have to have any particular size. Given that the n = max{size(self), size(other)}, it will produce a number of size n.

If other is bigger than self, Err(B - borrow) is returned.

Taken from “The Art of Computer Programming” by D.E. Knuth, vol 2, chapter 4.

pub fn mul(self, other: &BigUint) -> BigUint

Multiplies n-limb number self with m-limb number other.

The resulting number will always have n + m limbs.

This function does not strip the output and returns the original allocated n + m limbs. The caller may strip the output if desired.

Taken from “The Art of Computer Programming” by D.E. Knuth, vol 2, chapter 4.

pub fn div_unit(self, other: u32) -> BigUint

Divides self by a single limb other. This can be used in cases where the original division cannot work due to the divisor (other) being just one limb.

Invariant: other cannot be zero.

pub fn div(self, other: &BigUint, rem: bool) -> Option<(BigUint, BigUint)>

Divides an n + m limb self by a n limb other. The result is a m + 1 limb quotient and a n limb remainder, if enabled by passing true in rem argument, both in the form of an option’s Ok.