Skip to content

Implemented checked arithmetic for Big(U)Ints #12672

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Mar 4, 2014
Merged

Implemented checked arithmetic for Big(U)Ints #12672

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
233 changes: 233 additions & 0 deletions src/libnum/bigint.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ use Integer;
use std::cmp;
use std::fmt;
use std::from_str::FromStr;
use std::num::CheckedDiv;
use std::num::{Bitwise, ToPrimitive, FromPrimitive};
use std::num::{Zero, One, ToStrRadix, FromStrRadix};
use std::rand::Rng;
Expand Down Expand Up @@ -338,6 +339,40 @@ impl Neg<BigUint> for BigUint {
fn neg(&self) -> BigUint { fail!() }
}

impl CheckedAdd for BigUint {
#[inline]
fn checked_add(&self, v: &BigUint) -> Option<BigUint> {
return Some(self.add(v));
}
}

impl CheckedSub for BigUint {
#[inline]
fn checked_sub(&self, v: &BigUint) -> Option<BigUint> {
if *self < *v {
return None;
}
return Some(self.sub(v));
}
}

impl CheckedMul for BigUint {
#[inline]
fn checked_mul(&self, v: &BigUint) -> Option<BigUint> {
return Some(self.mul(v));
}
}

impl CheckedDiv for BigUint {
#[inline]
fn checked_div(&self, v: &BigUint) -> Option<BigUint> {
if v.is_zero() {
return None;
}
return Some(self.div(v));
}
}

impl Integer for BigUint {
#[inline]
fn div_rem(&self, other: &BigUint) -> (BigUint, BigUint) {
Expand Down Expand Up @@ -1053,6 +1088,38 @@ impl Neg<BigInt> for BigInt {
}
}

impl CheckedAdd for BigInt {
#[inline]
fn checked_add(&self, v: &BigInt) -> Option<BigInt> {
return Some(self.add(v));
}
}

impl CheckedSub for BigInt {
#[inline]
fn checked_sub(&self, v: &BigInt) -> Option<BigInt> {
return Some(self.sub(v));
}
}

impl CheckedMul for BigInt {
#[inline]
fn checked_mul(&self, v: &BigInt) -> Option<BigInt> {
return Some(self.mul(v));
}
}

impl CheckedDiv for BigInt {
#[inline]
fn checked_div(&self, v: &BigInt) -> Option<BigInt> {
if v.is_zero() {
return None;
}
return Some(self.div(v));
}
}


impl Integer for BigInt {
#[inline]
fn div_rem(&self, other: &BigInt) -> (BigInt, BigInt) {
Expand Down Expand Up @@ -1402,6 +1469,7 @@ mod biguint_tests {
use std::i64;
use std::num::{Zero, One, FromStrRadix, ToStrRadix};
use std::num::{ToPrimitive, FromPrimitive};
use std::num::CheckedDiv;
use std::rand::{task_rng};
use std::str;
use std::u64;
Expand Down Expand Up @@ -1822,6 +1890,82 @@ mod biguint_tests {
}
}

#[test]
fn test_checked_add() {
for elm in sum_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigUint::from_slice(aVec);
let b = BigUint::from_slice(bVec);
let c = BigUint::from_slice(cVec);

assert!(a.checked_add(&b).unwrap() == c);
assert!(b.checked_add(&a).unwrap() == c);
}
}

#[test]
fn test_checked_sub() {
for elm in sum_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigUint::from_slice(aVec);
let b = BigUint::from_slice(bVec);
let c = BigUint::from_slice(cVec);

assert!(c.checked_sub(&a).unwrap() == b);
assert!(c.checked_sub(&b).unwrap() == a);

if a > c {
assert!(a.checked_sub(&c).is_none());
}
if b > c {
assert!(b.checked_sub(&c).is_none());
}
}
}

#[test]
fn test_checked_mul() {
for elm in mul_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigUint::from_slice(aVec);
let b = BigUint::from_slice(bVec);
let c = BigUint::from_slice(cVec);

assert!(a.checked_mul(&b).unwrap() == c);
assert!(b.checked_mul(&a).unwrap() == c);
}

for elm in div_rem_quadruples.iter() {
let (aVec, bVec, cVec, dVec) = *elm;
let a = BigUint::from_slice(aVec);
let b = BigUint::from_slice(bVec);
let c = BigUint::from_slice(cVec);
let d = BigUint::from_slice(dVec);

assert!(a == b.checked_mul(&c).unwrap() + d);
assert!(a == c.checked_mul(&b).unwrap() + d);
}
}

#[test]
fn test_checked_div() {
for elm in mul_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigUint::from_slice(aVec);
let b = BigUint::from_slice(bVec);
let c = BigUint::from_slice(cVec);

if !a.is_zero() {
assert!(c.checked_div(&a).unwrap() == b);
}
if !b.is_zero() {
assert!(c.checked_div(&b).unwrap() == a);
}

assert!(c.checked_div(&Zero::zero()).is_none());
}
}

#[test]
fn test_gcd() {
fn check(a: uint, b: uint, c: uint) {
Expand Down Expand Up @@ -2058,6 +2202,7 @@ mod bigint_tests {

use std::cmp::{Less, Equal, Greater};
use std::i64;
use std::num::CheckedDiv;
use std::num::{Zero, One, FromStrRadix, ToStrRadix};
use std::num::{ToPrimitive, FromPrimitive};
use std::rand::{task_rng};
Expand Down Expand Up @@ -2399,6 +2544,94 @@ mod bigint_tests {
}
}

#[test]
fn test_checked_add() {
for elm in sum_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigInt::from_slice(Plus, aVec);
let b = BigInt::from_slice(Plus, bVec);
let c = BigInt::from_slice(Plus, cVec);

assert!(a.checked_add(&b).unwrap() == c);
assert!(b.checked_add(&a).unwrap() == c);
assert!(c.checked_add(&(-a)).unwrap() == b);
assert!(c.checked_add(&(-b)).unwrap() == a);
assert!(a.checked_add(&(-c)).unwrap() == (-b));
assert!(b.checked_add(&(-c)).unwrap() == (-a));
assert!((-a).checked_add(&(-b)).unwrap() == (-c))
assert!(a.checked_add(&(-a)).unwrap() == Zero::zero());
}
}

#[test]
fn test_checked_sub() {
for elm in sum_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigInt::from_slice(Plus, aVec);
let b = BigInt::from_slice(Plus, bVec);
let c = BigInt::from_slice(Plus, cVec);

assert!(c.checked_sub(&a).unwrap() == b);
assert!(c.checked_sub(&b).unwrap() == a);
assert!((-b).checked_sub(&a).unwrap() == (-c))
assert!((-a).checked_sub(&b).unwrap() == (-c))
assert!(b.checked_sub(&(-a)).unwrap() == c);
assert!(a.checked_sub(&(-b)).unwrap() == c);
assert!((-c).checked_sub(&(-a)).unwrap() == (-b));
assert!(a.checked_sub(&a).unwrap() == Zero::zero());
}
}

#[test]
fn test_checked_mul() {
for elm in mul_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigInt::from_slice(Plus, aVec);
let b = BigInt::from_slice(Plus, bVec);
let c = BigInt::from_slice(Plus, cVec);

assert!(a.checked_mul(&b).unwrap() == c);
assert!(b.checked_mul(&a).unwrap() == c);

assert!((-a).checked_mul(&b).unwrap() == -c);
assert!((-b).checked_mul(&a).unwrap() == -c);
}

for elm in div_rem_quadruples.iter() {
let (aVec, bVec, cVec, dVec) = *elm;
let a = BigInt::from_slice(Plus, aVec);
let b = BigInt::from_slice(Plus, bVec);
let c = BigInt::from_slice(Plus, cVec);
let d = BigInt::from_slice(Plus, dVec);

assert!(a == b.checked_mul(&c).unwrap() + d);
assert!(a == c.checked_mul(&b).unwrap() + d);
}
}
#[test]
fn test_checked_div() {
for elm in mul_triples.iter() {
let (aVec, bVec, cVec) = *elm;
let a = BigInt::from_slice(Plus, aVec);
let b = BigInt::from_slice(Plus, bVec);
let c = BigInt::from_slice(Plus, cVec);

if !a.is_zero() {
assert!(c.checked_div(&a).unwrap() == b);
assert!((-c).checked_div(&(-a)).unwrap() == b);
assert!((-c).checked_div(&a).unwrap() == -b);
}
if !b.is_zero() {
assert!(c.checked_div(&b).unwrap() == a);
assert!((-c).checked_div(&(-b)).unwrap() == a);
assert!((-c).checked_div(&b).unwrap() == -a);
}

assert!(c.checked_div(&Zero::zero()).is_none());
assert!((-c).checked_div(&Zero::zero()).is_none());
}
}

#[test]
fn test_gcd() {
fn check(a: int, b: int, c: int) {
Expand Down