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bigint: add From implementations #138

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merged 2 commits into from
Dec 13, 2015
Merged

bigint: add From implementations #138

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8e1c6a3
bigint: add From implementations
ollie27 Dec 6, 2015
9c7c995
bigint: add tests for From implementations
ollie27 Dec 12, 2015
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190 changes: 166 additions & 24 deletions src/bigint.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1105,27 +1105,47 @@ impl ToPrimitive for BigUint {
impl FromPrimitive for BigUint {
#[inline]
fn from_i64(n: i64) -> Option<BigUint> {
if n > 0 {
FromPrimitive::from_u64(n as u64)
} else if n == 0 {
Some(Zero::zero())
if n >= 0 {
Some(BigUint::from(n as u64))
} else {
None
}
}

// `DoubleBigDigit` size dependent
#[inline]
fn from_u64(n: u64) -> Option<BigUint> {
let n = match big_digit::from_doublebigdigit(n) {
(0, 0) => Zero::zero(),
(0, n0) => BigUint::new(vec!(n0)),
(n1, n0) => BigUint::new(vec!(n0, n1))
};
Some(n)
Some(BigUint::from(n))
}
}

impl From<u64> for BigUint {
// `DoubleBigDigit` size dependent
#[inline]
fn from(n: u64) -> Self {
match big_digit::from_doublebigdigit(n) {
(0, 0) => BigUint::zero(),
(0, n0) => BigUint { data: vec![n0] },
(n1, n0) => BigUint { data: vec![n0, n1] },
}
}
}

macro_rules! impl_biguint_from_uint {
($T:ty) => {
impl From<$T> for BigUint {
#[inline]
fn from(n: $T) -> Self {
BigUint::from(n as u64)
}
}
}
}

impl_biguint_from_uint!(u8);
impl_biguint_from_uint!(u16);
impl_biguint_from_uint!(u32);
impl_biguint_from_uint!(usize);

/// A generic trait for converting a value to a `BigUint`.
pub trait ToBigUint {
/// Converts the value of `self` to a `BigUint`.
Expand Down Expand Up @@ -1973,24 +1993,77 @@ impl ToPrimitive for BigInt {
impl FromPrimitive for BigInt {
#[inline]
fn from_i64(n: i64) -> Option<BigInt> {
Some(BigInt::from(n))
}

#[inline]
fn from_u64(n: u64) -> Option<BigInt> {
Some(BigInt::from(n))
}
}

impl From<i64> for BigInt {
#[inline]
fn from(n: i64) -> Self {
if n >= 0 {
FromPrimitive::from_u64(n as u64)
BigInt::from(n as u64)
} else {
let u = u64::MAX - (n as u64) + 1;
FromPrimitive::from_u64(u).map(|n| {
BigInt::from_biguint(Minus, n)
})
BigInt { sign: Minus, data: BigUint::from(u) }
}
}
}

macro_rules! impl_bigint_from_int {
($T:ty) => {
impl From<$T> for BigInt {
#[inline]
fn from(n: $T) -> Self {
BigInt::from(n as i64)
}
}
}
}

impl_bigint_from_int!(i8);
impl_bigint_from_int!(i16);
impl_bigint_from_int!(i32);
impl_bigint_from_int!(isize);

impl From<u64> for BigInt {
#[inline]
fn from_u64(n: u64) -> Option<BigInt> {
if n == 0 {
Some(Zero::zero())
fn from(n: u64) -> Self {
if n > 0 {
BigInt { sign: Plus, data: BigUint::from(n) }
} else {
BigInt::zero()
}
}
}

macro_rules! impl_bigint_from_uint {
($T:ty) => {
impl From<$T> for BigInt {
#[inline]
fn from(n: $T) -> Self {
BigInt::from(n as u64)
}
}
}
}

impl_bigint_from_uint!(u8);
impl_bigint_from_uint!(u16);
impl_bigint_from_uint!(u32);
impl_bigint_from_uint!(usize);

impl From<BigUint> for BigInt {
#[inline]
fn from(n: BigUint) -> Self {
if n.is_zero() {
BigInt::zero()
} else {
FromPrimitive::from_u64(n).map(|n| {
BigInt::from_biguint(Plus, n)
})
BigInt { sign: Plus, data: n }
}
}
}
Expand Down Expand Up @@ -2339,7 +2412,7 @@ mod biguint_tests {
use std::i64;
use std::iter::repeat;
use std::str::FromStr;
use std::u64;
use std::{u8, u16, u32, u64, usize};

use rand::thread_rng;
use {Num, Zero, One, CheckedAdd, CheckedSub, CheckedMul, CheckedDiv};
Expand Down Expand Up @@ -2834,6 +2907,24 @@ mod biguint_tests {
BigInt::from_biguint(Plus, BigUint::new(vec!(1,2,3))));
}

#[test]
fn test_convert_from_uint() {
macro_rules! check {
($ty:ident, $max:expr) => {
assert_eq!(BigUint::from($ty::zero()), BigUint::zero());
assert_eq!(BigUint::from($ty::one()), BigUint::one());
assert_eq!(BigUint::from($ty::MAX - $ty::one()), $max - BigUint::one());
assert_eq!(BigUint::from($ty::MAX), $max);
}
}

check!(u8, BigUint::from_slice(&[u8::MAX as BigDigit]));
check!(u16, BigUint::from_slice(&[u16::MAX as BigDigit]));
check!(u32, BigUint::from_slice(&[u32::MAX]));
check!(u64, BigUint::from_slice(&[u32::MAX, u32::MAX]));
check!(usize, BigUint::from(usize::MAX as u64));
}

const SUM_TRIPLES: &'static [(&'static [BigDigit],
&'static [BigDigit],
&'static [BigDigit])] = &[
Expand Down Expand Up @@ -3338,9 +3429,9 @@ mod bigint_tests {
use super::Sign::{Minus, NoSign, Plus};

use std::cmp::Ordering::{Less, Equal, Greater};
use std::i64;
use std::{i8, i16, i32, i64, isize};
use std::iter::repeat;
use std::u64;
use std::{u8, u16, u32, u64, usize};
use std::ops::{Neg};

use rand::thread_rng;
Expand Down Expand Up @@ -3564,6 +3655,57 @@ mod bigint_tests {
assert_eq!(negative.to_biguint(), None);
}

#[test]
fn test_convert_from_uint() {
macro_rules! check {
($ty:ident, $max:expr) => {
assert_eq!(BigInt::from($ty::zero()), BigInt::zero());
assert_eq!(BigInt::from($ty::one()), BigInt::one());
assert_eq!(BigInt::from($ty::MAX - $ty::one()), $max - BigInt::one());
assert_eq!(BigInt::from($ty::MAX), $max);
}
}

check!(u8, BigInt::from_slice(Plus, &[u8::MAX as BigDigit]));
check!(u16, BigInt::from_slice(Plus, &[u16::MAX as BigDigit]));
check!(u32, BigInt::from_slice(Plus, &[u32::MAX as BigDigit]));
check!(u64, BigInt::from_slice(Plus, &[u32::MAX as BigDigit, u32::MAX as BigDigit]));
check!(usize, BigInt::from(usize::MAX as u64));
}

#[test]
fn test_convert_from_int() {
macro_rules! check {
($ty:ident, $min:expr, $max:expr) => {
assert_eq!(BigInt::from($ty::MIN), $min);
assert_eq!(BigInt::from($ty::MIN + $ty::one()), $min + BigInt::one());
assert_eq!(BigInt::from(-$ty::one()), -BigInt::one());
assert_eq!(BigInt::from($ty::zero()), BigInt::zero());
assert_eq!(BigInt::from($ty::one()), BigInt::one());
assert_eq!(BigInt::from($ty::MAX - $ty::one()), $max - BigInt::one());
assert_eq!(BigInt::from($ty::MAX), $max);
}
}

check!(i8, BigInt::from_slice(Minus, &[1 << 7]),
BigInt::from_slice(Plus, &[i8::MAX as BigDigit]));
check!(i16, BigInt::from_slice(Minus, &[1 << 15]),
BigInt::from_slice(Plus, &[i16::MAX as BigDigit]));
check!(i32, BigInt::from_slice(Minus, &[1 << 31]),
BigInt::from_slice(Plus, &[i32::MAX as BigDigit]));
check!(i64, BigInt::from_slice(Minus, &[0, 1 << 31]),
BigInt::from_slice(Plus, &[u32::MAX as BigDigit, i32::MAX as BigDigit]));
check!(isize, BigInt::from(isize::MIN as i64),
BigInt::from(isize::MAX as i64));
}

#[test]
fn test_convert_from_biguint() {
assert_eq!(BigInt::from(BigUint::zero()), BigInt::zero());
assert_eq!(BigInt::from(BigUint::one()), BigInt::one());
assert_eq!(BigInt::from(BigUint::from_slice(&[1, 2, 3])), BigInt::from_slice(Plus, &[1, 2, 3]));
}

const N1: BigDigit = -1i32 as BigDigit;
const N2: BigDigit = -2i32 as BigDigit;

Expand Down