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#![no_std]
#[cfg(feature="pdqsort")]
extern crate pdqsort;
use core::cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd};
use core::mem::transmute;
#[derive(Clone, Copy)]
pub struct FloatOrd<T>(pub T);
macro_rules! float_ord_impl {
($f:ident, $i:ident, $n:expr) => {
impl FloatOrd<$f> {
fn convert(self) -> $i {
let u = unsafe { transmute::<$f, $i>(self.0) };
let bit = 1 << ($n - 1);
if u & bit == 0 {
u | bit
} else {
!u
}
}
}
impl PartialEq for FloatOrd<$f> {
fn eq(&self, other: &Self) -> bool {
self.convert() == other.convert()
}
}
impl Eq for FloatOrd<$f> {}
impl PartialOrd for FloatOrd<$f> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.convert().partial_cmp(&other.convert())
}
}
impl Ord for FloatOrd<$f> {
fn cmp(&self, other: &Self) -> Ordering {
self.convert().cmp(&other.convert())
}
}
}
}
float_ord_impl!(f32, u32, 32);
float_ord_impl!(f64, u64, 64);
#[cfg(feature="pdqsort")]
pub fn sort<T>(v: &mut [T]) where FloatOrd<T>: Ord {
let v_: &mut [FloatOrd<T>] = unsafe { transmute(v) };
pdqsort::sort(v_);
}
#[cfg(test)]
mod tests {
extern crate std;
extern crate rand;
use self::rand::{Rng, thread_rng};
use self::std::prelude::v1::*;
use super::FloatOrd;
#[test]
fn test_ord() {
assert!(FloatOrd(1.0f64) < FloatOrd(2.0f64));
assert!(FloatOrd(2.0f32) > FloatOrd(1.0f32));
assert!(FloatOrd(1.0f64) == FloatOrd(1.0f64));
assert!(FloatOrd(1.0f32) == FloatOrd(1.0f32));
assert!(FloatOrd(0.0f64) > FloatOrd(-0.0f64));
assert!(FloatOrd(0.0f32) > FloatOrd(-0.0f32));
assert!(FloatOrd(::core::f64::NAN) == FloatOrd(::core::f64::NAN));
assert!(FloatOrd(::core::f32::NAN) == FloatOrd(::core::f32::NAN));
assert!(FloatOrd(-::core::f64::NAN) < FloatOrd(::core::f64::NAN));
assert!(FloatOrd(-::core::f32::NAN) < FloatOrd(::core::f32::NAN));
assert!(FloatOrd(-::core::f64::INFINITY) < FloatOrd(::core::f64::INFINITY));
assert!(FloatOrd(-::core::f32::INFINITY) < FloatOrd(::core::f32::INFINITY));
assert!(FloatOrd(::core::f64::INFINITY) < FloatOrd(::core::f64::NAN));
assert!(FloatOrd(::core::f32::INFINITY) < FloatOrd(::core::f32::NAN));
assert!(FloatOrd(-::core::f64::NAN) < FloatOrd(::core::f64::INFINITY));
assert!(FloatOrd(-::core::f32::NAN) < FloatOrd(::core::f32::INFINITY));
}
#[test]
fn test_ord_numbers() {
let mut rng = thread_rng();
for n in 0..16 {
for l in 0..16 {
let v = rng.gen_iter::<f64>()
.map(|x| x % (1 << l) as i64 as f64)
.take((1 << n))
.collect::<Vec<_>>();
assert!(v.windows(2).all(|w| (w[0] <= w[1]) == (FloatOrd(w[0]) <= FloatOrd(w[1]))));
}
}
}
#[cfg(feature="pdqsort")]
#[test]
fn test_sort_numbers() {
let mut rng = thread_rng();
for n in 0..16 {
for l in 0..16 {
let mut v = rng.gen_iter::<f64>()
.map(|x| x % (1 << l) as i64 as f64)
.take((1 << n))
.collect::<Vec<_>>();
let mut v1 = v.clone();
super::sort(&mut v);
assert!(v.windows(2).all(|w| w[0] <= w[1]));
v1.sort_by(|a, b| a.partial_cmp(b).unwrap());
assert!(v1.windows(2).all(|w| w[0] <= w[1]));
v1.sort_by(|a, b| b.partial_cmp(a).unwrap());
assert!(v1.windows(2).all(|w| w[0] >= w[1]));
}
}
let mut v = [5.0];
super::sort(&mut v);
assert!(v == [5.0]);
}
#[cfg(feature="pdqsort")]
#[test]
fn test_sort_nan() {
let nan = ::core::f64::NAN;
let mut v = [-1.0, 5.0, 0.0, -0.0, nan, 1.5, nan, 3.7];
super::sort(&mut v);
assert!(v[0] == -1.0);
assert!(v[1] == 0.0 && v[1].is_sign_negative());
assert!(v[2] == 0.0 && !v[2].is_sign_negative());
assert!(v[3] == 1.5);
assert!(v[4] == 3.7);
assert!(v[5] == 5.0);
assert!(v[6].is_nan());
assert!(v[7].is_nan());
}
}