use crate::error::{FendError, Interrupt};
use crate::format::Format;
use crate::interrupt::test_int;
use crate::num::{out_of_range, Base, Exact, Range, RangeBound};
use crate::serialize::{
deserialize_u64, deserialize_u8, deserialize_usize, serialize_u64, serialize_u8,
serialize_usize,
};
use std::cmp::{max, Ordering};
use std::{fmt, hash, io};
#[derive(Clone)]
pub(crate) enum BigUint {
Small(u64),
Large(Vec<u64>),
}
impl hash::Hash for BigUint {
fn hash<H: hash::Hasher>(&self, state: &mut H) {
match self {
Small(u) => u.hash(state),
Large(v) => {
for u in v {
u.hash(state);
}
}
}
}
}
use BigUint::{Large, Small};
#[allow(clippy::cast_possible_truncation)]
const fn truncate(n: u128) -> u64 {
n as u64
}
impl BigUint {
fn is_zero(&self) -> bool {
match self {
Small(n) => *n == 0,
Large(value) => {
for v in value.iter() {
if *v != 0 {
return false;
}
}
true
}
}
}
fn get(&self, idx: usize) -> u64 {
match self {
Small(n) => {
if idx == 0 {
*n
} else {
0
}
}
Large(value) => {
if idx < value.len() {
value[idx]
} else {
0
}
}
}
}
pub(crate) fn try_as_usize<I: Interrupt>(&self, int: &I) -> Result<usize, FendError> {
let error = || -> Result<_, FendError> {
Ok(out_of_range(
self.fm(int)?,
Range {
start: RangeBound::Closed(0),
end: RangeBound::Closed(usize::MAX),
},
))
};
Ok(match self {
Small(n) => {
if let Ok(res) = usize::try_from(*n) {
res
} else {
return Err(error()?);
}
}
Large(v) => {
if v.len() == 1 {
if let Ok(res) = usize::try_from(v[0]) {
res
} else {
return Err(error()?);
}
} else {
return Err(error()?);
}
}
})
}
#[allow(clippy::cast_precision_loss)]
pub(crate) fn as_f64(&self) -> f64 {
match self {
Small(n) => *n as f64,
Large(v) => {
let mut res = 0.0;
for &n in v.iter().rev() {
res *= u64::MAX as f64;
res += n as f64;
}
res
}
}
}
fn make_large(&mut self) {
match self {
Small(n) => {
*self = Large(vec![*n]);
}
Large(_) => (),
}
}
fn set(&mut self, idx: usize, new_value: u64) {
match self {
Small(n) => {
if idx == 0 {
*n = new_value;
} else if new_value == 0 {
} else {
self.make_large();
self.set(idx, new_value);
}
}
Large(value) => {
while idx >= value.len() {
value.push(0);
}
value[idx] = new_value;
}
}
}
fn value_len(&self) -> usize {
match self {
Small(_) => 1,
Large(value) => value.len(),
}
}
fn value_push(&mut self, new: u64) {
if new == 0 {
return;
}
self.make_large();
match self {
Small(_) => unreachable!(),
Large(v) => v.push(new),
}
}
pub(crate) fn gcd<I: Interrupt>(mut a: Self, mut b: Self, int: &I) -> Result<Self, FendError> {
while b >= 1.into() {
let r = a.rem(&b, int)?;
a = b;
b = r;
}
Ok(a)
}
pub(crate) fn pow<I: Interrupt>(a: &Self, b: &Self, int: &I) -> Result<Self, FendError> {
if a.is_zero() && b.is_zero() {
return Err(FendError::ZeroToThePowerOfZero);
}
if b.is_zero() {
return Ok(Self::from(1));
}
if b.value_len() > 1 {
return Err(FendError::ExponentTooLarge);
}
a.pow_internal(b.get(0), int)
}
pub(crate) fn root_n<I: Interrupt>(self, n: &Self, int: &I) -> Result<Exact<Self>, FendError> {
if self == 0.into() || self == 1.into() || n == &Self::from(1) {
return Ok(Exact::new(self, true));
}
let mut low_guess = Self::from(1);
let mut high_guess = self.clone();
while high_guess.clone().sub(&low_guess) > 1.into() {
test_int(int)?;
let mut guess = low_guess.clone().add(&high_guess);
guess.rshift(int)?;
let res = Self::pow(&guess, n, int)?;
match res.cmp(&self) {
Ordering::Equal => return Ok(Exact::new(guess, true)),
Ordering::Greater => high_guess = guess,
Ordering::Less => low_guess = guess,
}
}
Ok(Exact::new(low_guess, false))
}
fn pow_internal<I: Interrupt>(&self, mut exponent: u64, int: &I) -> Result<Self, FendError> {
let mut result = Self::from(1);
let mut base = self.clone();
while exponent > 0 {
test_int(int)?;
if exponent % 2 == 1 {
result = result.mul(&base, int)?;
}
exponent >>= 1;
base = base.clone().mul(&base, int)?;
}
Ok(result)
}
fn lshift<I: Interrupt>(&mut self, int: &I) -> Result<(), FendError> {
match self {
Small(n) => {
if *n & 0xc000_0000_0000_0000 == 0 {
*n <<= 1;
} else {
*self = Large(vec![*n << 1, *n >> 63]);
}
}
Large(value) => {
if value[value.len() - 1] & (1_u64 << 63) != 0 {
value.push(0);
}
for i in (0..value.len()).rev() {
test_int(int)?;
value[i] <<= 1;
if i != 0 {
value[i] |= value[i - 1] >> 63;
}
}
}
}
Ok(())
}
fn rshift<I: Interrupt>(&mut self, int: &I) -> Result<(), FendError> {
match self {
Small(n) => *n >>= 1,
Large(value) => {
for i in 0..value.len() {
test_int(int)?;
value[i] >>= 1;
let next = if i + 1 >= value.len() {
0
} else {
value[i + 1]
};
value[i] |= next << 63;
}
}
}
Ok(())
}
pub(crate) fn divmod<I: Interrupt>(
&self,
other: &Self,
int: &I,
) -> Result<(Self, Self), FendError> {
if let (Small(a), Small(b)) = (self, other) {
if let (Some(div_res), Some(mod_res)) = (a.checked_div(*b), a.checked_rem(*b)) {
return Ok((Small(div_res), Small(mod_res)));
}
return Err(FendError::DivideByZero);
}
if other.is_zero() {
return Err(FendError::DivideByZero);
}
if other == &Self::from(1) {
return Ok((self.clone(), Self::from(0)));
}
if self.is_zero() {
return Ok((Self::from(0), Self::from(0)));
}
if self < other {
return Ok((Self::from(0), self.clone()));
}
if self == other {
return Ok((Self::from(1), Self::from(0)));
}
if other == &Self::from(2) {
let mut div_result = self.clone();
div_result.rshift(int)?;
let modulo = self.get(0) & 1;
return Ok((div_result, Self::from(modulo)));
}
let mut q = Self::from(0);
let mut r = Self::from(0);
for i in (0..self.value_len()).rev() {
test_int(int)?;
for j in (0..64).rev() {
r.lshift(int)?;
let bit_of_self = u64::from((self.get(i) & (1 << j)) != 0);
r.set(0, r.get(0) | bit_of_self);
if &r >= other {
r = r.sub(other);
q.set(i, q.get(i) | (1 << j));
}
}
}
Ok((q, r))
}
fn mul_internal<I: Interrupt>(&mut self, other: &Self, int: &I) -> Result<(), FendError> {
if self.is_zero() || other.is_zero() {
*self = Self::from(0);
return Ok(());
}
let self_clone = self.clone();
self.make_large();
match self {
Small(_) => unreachable!(),
Large(v) => {
v.clear();
v.push(0);
}
}
for i in 0..other.value_len() {
test_int(int)?;
self.add_assign_internal(&self_clone, other.get(i), i);
}
Ok(())
}
fn add_assign_internal(&mut self, other: &Self, mul_digit: u64, shift: usize) {
let mut carry = 0;
for i in 0..max(self.value_len(), other.value_len() + shift) {
let a = self.get(i);
let b = if i >= shift { other.get(i - shift) } else { 0 };
let sum = u128::from(a) + (u128::from(b) * u128::from(mul_digit)) + u128::from(carry);
self.set(i, truncate(sum));
carry = truncate(sum >> 64);
}
if carry != 0 {
self.value_push(carry);
}
}
pub(crate) fn factorial<I: Interrupt>(mut self, int: &I) -> Result<Self, FendError> {
let mut res = Self::from(1);
while self > 1.into() {
test_int(int)?;
res = res.mul(&self, int)?;
self = self.sub(&1.into());
}
Ok(res)
}
pub(crate) fn mul<I: Interrupt>(mut self, other: &Self, int: &I) -> Result<Self, FendError> {
if let (Small(a), Small(b)) = (&self, &other) {
if let Some(res) = a.checked_mul(*b) {
return Ok(Self::from(res));
}
}
self.mul_internal(other, int)?;
Ok(self)
}
fn rem<I: Interrupt>(&self, other: &Self, int: &I) -> Result<Self, FendError> {
Ok(self.divmod(other, int)?.1)
}
pub(crate) fn is_even<I: Interrupt>(&self, int: &I) -> Result<bool, FendError> {
Ok(self.divmod(&Self::from(2), int)?.1 == 0.into())
}
pub(crate) fn div<I: Interrupt>(self, other: &Self, int: &I) -> Result<Self, FendError> {
Ok(self.divmod(other, int)?.0)
}
pub(crate) fn add(mut self, other: &Self) -> Self {
self.add_assign_internal(other, 1, 0);
self
}
pub(crate) fn sub(self, other: &Self) -> Self {
if let (Small(a), Small(b)) = (&self, &other) {
return Self::from(a - b);
}
match self.cmp(other) {
Ordering::Equal => return Self::from(0),
Ordering::Less => unreachable!("number would be less than 0"),
Ordering::Greater => (),
};
if other.is_zero() {
return self;
}
let mut carry = 0; let mut res = match self {
Large(x) => x,
Small(v) => vec![v],
};
if res.len() < other.value_len() {
res.resize(other.value_len(), 0);
}
for (i, a) in res.iter_mut().enumerate() {
let b = other.get(i);
if !(b == std::u64::MAX && carry == 1) && *a >= b + carry {
*a = *a - b - carry;
carry = 0;
} else {
let next_digit =
u128::from(*a) + ((1_u128) << 64) - u128::from(b) - u128::from(carry);
*a = truncate(next_digit);
carry = 1;
}
}
assert_eq!(carry, 0);
Large(res)
}
pub(crate) const fn is_definitely_zero(&self) -> bool {
match self {
Small(x) => *x == 0,
Large(_) => false,
}
}
pub(crate) const fn is_definitely_one(&self) -> bool {
match self {
Small(x) => *x == 1,
Large(_) => false,
}
}
pub(crate) fn serialize(&self, write: &mut impl io::Write) -> Result<(), FendError> {
match self {
Small(x) => {
serialize_u8(1, write)?;
serialize_u64(*x, write)?;
}
Large(v) => {
serialize_u8(2, write)?;
serialize_usize(v.len(), write)?;
for b in v {
serialize_u64(*b, write)?;
}
}
}
Ok(())
}
pub(crate) fn deserialize(read: &mut impl io::Read) -> Result<Self, FendError> {
let kind = deserialize_u8(read)?;
Ok(match kind {
1 => Self::Small(deserialize_u64(read)?),
2 => {
let len = deserialize_usize(read)?;
let mut v = Vec::with_capacity(len);
for _ in 0..len {
v.push(deserialize_u64(read)?);
}
Self::Large(v)
}
_ => return Err(FendError::DeserializationError),
})
}
pub(crate) fn bitwise_and(self, rhs: &Self) -> Self {
match (self, rhs) {
(Small(a), Small(b)) => Small(a & *b),
(Large(a), Small(b)) => Small(a[0] & *b),
(Small(a), Large(b)) => Small(a & b[0]),
(Large(a), Large(b)) => {
let mut result = b.clone();
for (i, res_i) in result.iter_mut().enumerate() {
*res_i &= a.get(i).unwrap_or(&0);
}
Large(result)
}
}
}
pub(crate) fn bitwise_or(self, rhs: &Self) -> Self {
match (self, rhs) {
(Small(a), Small(b)) => Small(a | *b),
(Large(mut a), Small(b)) => {
a[0] |= b;
Large(a)
}
(Small(a), Large(b)) => {
let mut result = b.clone();
result[0] |= a;
Large(result)
}
(Large(mut a), Large(b)) => {
while a.len() < b.len() {
a.push(0);
}
for i in 0..b.len() {
a[i] |= b[i];
}
Large(a)
}
}
}
pub(crate) fn bitwise_xor(self, rhs: &Self) -> Self {
match (self, rhs) {
(Small(a), Small(b)) => Small(a ^ *b),
(Large(mut a), Small(b)) => {
a[0] ^= b;
Large(a)
}
(Small(a), Large(b)) => {
let mut result = b.clone();
result[0] ^= a;
Large(result)
}
(Large(mut a), Large(b)) => {
while a.len() < b.len() {
a.push(0);
}
for i in 0..b.len() {
a[i] ^= b[i];
}
Large(a)
}
}
}
pub(crate) fn lshift_n<I: Interrupt>(mut self, rhs: &Self, int: &I) -> Result<Self, FendError> {
let mut rhs = rhs.try_as_usize(int)?;
if rhs > 64 {
self.make_large();
match &mut self {
Large(v) => {
while rhs >= 64 {
v.insert(0, 0);
rhs -= 64;
}
}
Small(_) => unreachable!(),
}
}
for _ in 0..rhs {
self.lshift(int)?;
}
Ok(self)
}
pub(crate) fn rshift_n<I: Interrupt>(mut self, rhs: &Self, int: &I) -> Result<Self, FendError> {
let rhs = rhs.try_as_usize(int)?;
for _ in 0..rhs {
if self.is_zero() {
break;
}
self.rshift(int)?;
}
Ok(self)
}
}
impl Ord for BigUint {
fn cmp(&self, other: &Self) -> Ordering {
if let (Small(a), Small(b)) = (self, other) {
return a.cmp(b);
}
let mut i = std::cmp::max(self.value_len(), other.value_len());
while i != 0 {
let v1 = self.get(i - 1);
let v2 = other.get(i - 1);
match v1.cmp(&v2) {
Ordering::Less => return Ordering::Less,
Ordering::Greater => return Ordering::Greater,
Ordering::Equal => (),
}
i -= 1;
}
Ordering::Equal
}
}
impl PartialOrd for BigUint {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for BigUint {
fn eq(&self, other: &Self) -> bool {
self.cmp(other) == Ordering::Equal
}
}
impl Eq for BigUint {}
impl From<u64> for BigUint {
fn from(val: u64) -> Self {
Small(val)
}
}
impl fmt::Debug for BigUint {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Small(n) => write!(f, "{n}")?,
Large(value) => {
write!(f, "[")?;
let mut first = true;
for v in value.iter().rev() {
if !first {
write!(f, ", ")?;
}
write!(f, "{v}")?;
first = false;
}
write!(f, "]")?;
}
}
Ok(())
}
}
#[derive(Default)]
pub(crate) struct FormatOptions {
pub(crate) base: Base,
pub(crate) write_base_prefix: bool,
pub(crate) sf_limit: Option<usize>,
}
impl Format for BigUint {
type Params = FormatOptions;
type Out = FormattedBigUint;
fn format<I: Interrupt>(
&self,
params: &Self::Params,
int: &I,
) -> Result<Exact<Self::Out>, FendError> {
let base_prefix = if params.write_base_prefix {
Some(params.base)
} else {
None
};
if self.is_zero() {
return Ok(Exact::new(
FormattedBigUint {
base: base_prefix,
ty: FormattedBigUintType::Zero,
},
true,
));
}
let mut num = self.clone();
Ok(
if num.value_len() == 1 && params.base.base_as_u8() == 10 && params.sf_limit.is_none() {
Exact::new(
FormattedBigUint {
base: base_prefix,
ty: FormattedBigUintType::Simple(num.get(0)),
},
true,
)
} else {
let base_as_u128: u128 = params.base.base_as_u8().into();
let mut divisor = base_as_u128;
let mut rounds = 1;
let mut num_trailing_zeroes = 0;
let mut num_leading_zeroes = 0;
let mut finished_counting_leading_zeroes = false;
while divisor
< u128::MAX
.checked_div(base_as_u128)
.expect("base appears to be 0")
{
divisor *= base_as_u128;
rounds += 1;
}
let divisor = Self::Large(vec![truncate(divisor), truncate(divisor >> 64)]);
let mut output = String::with_capacity(rounds);
while !num.is_zero() {
test_int(int)?;
let divmod_res = num.divmod(&divisor, int)?;
let mut digit_group_value =
u128::from(divmod_res.1.get(1)) << 64 | u128::from(divmod_res.1.get(0));
for _ in 0..rounds {
let digit_value = digit_group_value % base_as_u128;
digit_group_value /= base_as_u128;
let ch = Base::digit_as_char(truncate(digit_value)).unwrap();
if ch == '0' {
num_trailing_zeroes += 1;
} else {
for _ in 0..num_trailing_zeroes {
output.push('0');
if !finished_counting_leading_zeroes {
num_leading_zeroes += 1;
}
}
finished_counting_leading_zeroes = true;
num_trailing_zeroes = 0;
output.push(ch);
}
}
num = divmod_res.0;
}
let exact = params
.sf_limit
.map_or(true, |sf| sf >= output.len() - num_leading_zeroes);
Exact::new(
FormattedBigUint {
base: base_prefix,
ty: FormattedBigUintType::Complex(output, params.sf_limit),
},
exact,
)
},
)
}
}
#[derive(Debug)]
enum FormattedBigUintType {
Zero,
Simple(u64),
Complex(String, Option<usize>),
}
#[must_use]
#[derive(Debug)]
pub(crate) struct FormattedBigUint {
base: Option<Base>,
ty: FormattedBigUintType,
}
impl fmt::Display for FormattedBigUint {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
if let Some(base) = self.base {
base.write_prefix(f)?;
}
match &self.ty {
FormattedBigUintType::Zero => write!(f, "0")?,
FormattedBigUintType::Simple(i) => write!(f, "{i}")?,
FormattedBigUintType::Complex(s, sf_limit) => {
for (i, ch) in s.chars().rev().enumerate() {
if sf_limit.is_some() && &Some(i) >= sf_limit {
write!(f, "0")?;
} else {
write!(f, "{ch}")?;
}
}
}
}
Ok(())
}
}
impl FormattedBigUint {
pub(crate) fn num_digits(&self) -> usize {
match &self.ty {
FormattedBigUintType::Zero => 1,
FormattedBigUintType::Simple(i) => {
if *i <= 9 {
1
} else {
i.to_string().len()
}
}
FormattedBigUintType::Complex(s, _) => s.len(),
}
}
}
#[cfg(test)]
mod tests {
use super::BigUint;
type Res = Result<(), crate::error::FendError>;
#[test]
fn test_sqrt() -> Res {
let two = &BigUint::from(2);
let int = crate::interrupt::Never::default();
let test_sqrt_inner = |n, expected_root, exact| -> Res {
let actual = BigUint::from(n).root_n(two, &int)?;
assert_eq!(actual.value, BigUint::from(expected_root));
assert_eq!(actual.exact, exact);
Ok(())
};
test_sqrt_inner(0, 0, true)?;
test_sqrt_inner(1, 1, true)?;
test_sqrt_inner(2, 1, false)?;
test_sqrt_inner(3, 1, false)?;
test_sqrt_inner(4, 2, true)?;
test_sqrt_inner(5, 2, false)?;
test_sqrt_inner(6, 2, false)?;
test_sqrt_inner(7, 2, false)?;
test_sqrt_inner(8, 2, false)?;
test_sqrt_inner(9, 3, true)?;
test_sqrt_inner(10, 3, false)?;
test_sqrt_inner(11, 3, false)?;
test_sqrt_inner(12, 3, false)?;
test_sqrt_inner(13, 3, false)?;
test_sqrt_inner(14, 3, false)?;
test_sqrt_inner(15, 3, false)?;
test_sqrt_inner(16, 4, true)?;
test_sqrt_inner(17, 4, false)?;
test_sqrt_inner(18, 4, false)?;
test_sqrt_inner(19, 4, false)?;
test_sqrt_inner(20, 4, false)?;
test_sqrt_inner(200_000, 447, false)?;
test_sqrt_inner(1_740_123_984_719_364_372, 1_319_137_591, false)?;
let val = BigUint::Large(vec![0, 3_260_954_456_333_195_555]).root_n(two, &int)?;
assert_eq!(val.value, BigUint::from(7_755_900_482_342_532_476));
assert!(!val.exact);
Ok(())
}
#[test]
fn test_cmp() {
assert_eq!(BigUint::from(0), BigUint::from(0));
assert!(BigUint::from(0) < BigUint::from(1));
assert!(BigUint::from(100) > BigUint::from(1));
assert!(BigUint::from(10_000_000) > BigUint::from(1));
assert!(BigUint::from(10_000_000) > BigUint::from(9_999_999));
}
#[test]
fn test_addition() {
assert_eq!(BigUint::from(2).add(&BigUint::from(2)), BigUint::from(4));
assert_eq!(BigUint::from(5).add(&BigUint::from(3)), BigUint::from(8));
assert_eq!(
BigUint::from(0).add(&BigUint::Large(vec![0, 9_223_372_036_854_775_808, 0])),
BigUint::Large(vec![0, 9_223_372_036_854_775_808, 0])
);
}
#[test]
fn test_sub() {
assert_eq!(BigUint::from(5).sub(&BigUint::from(3)), BigUint::from(2));
assert_eq!(BigUint::from(0).sub(&BigUint::from(0)), BigUint::from(0));
}
#[test]
fn test_multiplication() -> Res {
let int = &crate::interrupt::Never::default();
assert_eq!(
BigUint::from(20).mul(&BigUint::from(3), int)?,
BigUint::from(60)
);
Ok(())
}
#[test]
fn test_small_division_by_two() -> Res {
let int = &crate::interrupt::Never::default();
let two = BigUint::from(2);
assert_eq!(BigUint::from(0).div(&two, int)?, BigUint::from(0));
assert_eq!(BigUint::from(1).div(&two, int)?, BigUint::from(0));
assert_eq!(BigUint::from(2).div(&two, int)?, BigUint::from(1));
assert_eq!(BigUint::from(3).div(&two, int)?, BigUint::from(1));
assert_eq!(BigUint::from(4).div(&two, int)?, BigUint::from(2));
assert_eq!(BigUint::from(5).div(&two, int)?, BigUint::from(2));
assert_eq!(BigUint::from(6).div(&two, int)?, BigUint::from(3));
assert_eq!(BigUint::from(7).div(&two, int)?, BigUint::from(3));
assert_eq!(BigUint::from(8).div(&two, int)?, BigUint::from(4));
Ok(())
}
#[test]
fn test_rem() -> Res {
let int = &crate::interrupt::Never::default();
let three = BigUint::from(3);
assert_eq!(BigUint::from(20).rem(&three, int)?, BigUint::from(2));
assert_eq!(BigUint::from(21).rem(&three, int)?, BigUint::from(0));
assert_eq!(BigUint::from(22).rem(&three, int)?, BigUint::from(1));
assert_eq!(BigUint::from(23).rem(&three, int)?, BigUint::from(2));
assert_eq!(BigUint::from(24).rem(&three, int)?, BigUint::from(0));
Ok(())
}
#[test]
fn test_lshift() -> Res {
let int = &crate::interrupt::Never::default();
let mut n = BigUint::from(1);
for _ in 0..100 {
n.lshift(int)?;
assert_eq!(n.get(0) & 1, 0);
}
Ok(())
}
#[test]
fn test_gcd() -> Res {
let int = &crate::interrupt::Never::default();
assert_eq!(BigUint::gcd(2.into(), 4.into(), int)?, 2.into());
assert_eq!(BigUint::gcd(4.into(), 2.into(), int)?, 2.into());
assert_eq!(BigUint::gcd(37.into(), 43.into(), int)?, 1.into());
assert_eq!(BigUint::gcd(43.into(), 37.into(), int)?, 1.into());
assert_eq!(BigUint::gcd(215.into(), 86.into(), int)?, 43.into());
assert_eq!(BigUint::gcd(86.into(), 215.into(), int)?, 43.into());
Ok(())
}
#[test]
fn test_add_assign_internal() {
let mut x = BigUint::from(0);
x.add_assign_internal(&BigUint::from(1), 1, 1);
assert_eq!(x, BigUint::Large(vec![0, 1]));
}
#[test]
fn test_large_lshift() -> Res {
let int = &crate::interrupt::Never::default();
let mut a = BigUint::from(9_223_372_036_854_775_808);
a.lshift(int)?;
assert!(!a.is_zero());
Ok(())
}
#[test]
fn test_big_multiplication() -> Res {
let int = &crate::interrupt::Never::default();
assert_eq!(
BigUint::from(1).mul(&BigUint::Large(vec![0, 1]), int)?,
BigUint::Large(vec![0, 1])
);
Ok(())
}
}