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use num_rational::Rational;
use num_traits::{Signed, Zero};
use std::fmt::{self, Write};
use std::ops::{Add, Div, Mul, Neg, Sub};
use std::sync::atomic::{AtomicUsize, Ordering};
static PRECISION: AtomicUsize = AtomicUsize::new(5);
pub fn set_precision(precision: usize) {
PRECISION.store(precision, Ordering::Relaxed);
}
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct Number {
pub value: Rational,
pub plus_sign: bool,
pub lead_zero: bool,
}
impl Number {
pub fn abs(self) -> Self {
Number {
value: self.value.abs(),
plus_sign: self.plus_sign,
lead_zero: self.lead_zero,
}
}
pub fn is_integer(&self) -> bool {
self.value.is_integer()
}
pub fn to_integer(&self) -> isize {
self.value.to_integer()
}
}
impl<T> From<T> for Number
where
T: Into<Rational>,
{
fn from(value: T) -> Number {
Number {
value: value.into(),
plus_sign: false,
lead_zero: true,
}
}
}
impl Add for Number {
type Output = Number;
fn add(self, rhs: Self) -> Self::Output {
Number::from(self.value + rhs.value)
}
}
impl<'a> Div for &'a Number {
type Output = Number;
fn div(self, rhs: Self) -> Self::Output {
Number::from(self.value / rhs.value)
}
}
impl<'a> Mul for &'a Number {
type Output = Number;
fn mul(self, rhs: Self) -> Self::Output {
Number::from(self.value * rhs.value)
}
}
impl<'a> Neg for &'a Number {
type Output = Number;
fn neg(self) -> Number {
Number::from(-self.value)
}
}
impl<'a> Sub for &'a Number {
type Output = Number;
fn sub(self, rhs: Self) -> Self::Output {
Number::from(self.value - rhs.value)
}
}
impl Zero for Number {
fn zero() -> Self {
Number::from(0)
}
fn is_zero(&self) -> bool {
self.value.is_zero()
}
}
impl fmt::Display for Number {
fn fmt(&self, out: &mut fmt::Formatter) -> fmt::Result {
let t = self.value.to_integer();
let skip_zero = out.alternate() || !self.lead_zero;
if t == 0 {
if self.value.is_negative() {
out.write_str("-")?;
if !skip_zero {
out.write_str("0")?;
}
} else if self.plus_sign {
out.write_str("+0")?;
} else if self.value.is_zero() || !skip_zero {
out.write_char('0')?;
}
} else {
if self.plus_sign && !t.is_negative() {
out.write_char('+')?;
}
write!(out, "{}", t)?;
}
let mut f = self.value.fract().abs();
if !f.is_zero() {
out.write_char('.')?;
for _ in 0..(PRECISION.load(Ordering::Relaxed) - 1) {
f *= 10;
write!(out, "{}", f.to_integer())?;
f = f.fract();
if f.is_zero() {
break;
}
}
if !f.is_zero() {
write!(out, "{}", (f * 10).round().to_integer())?;
}
}
Ok(())
}
}