aterm/
bad_idea.rs

1use std::mem;
2use std::hash;
3
4/// An f32 with broken Eq and Hash implementations.
5/// To quote shepmaster (except this is an f32):
6/// > Basically, if you want to treat a f64 as a set of bits that have no meaning, well, we can
7/// > treat them as an equivalently sized bag of bits that know how to be hashed and
8/// > bitwise-compared.
9/// > Don't be surprised when one of the 16 million NaN values doesn't equal another one.
10/// http://stackoverflow.com/q/39638363/859279
11#[derive(Debug, Clone, Copy)]
12pub struct BrokenF32(pub f32);
13
14impl BrokenF32 {
15    fn key(&self) -> u32 {
16        unsafe { mem::transmute(self.0) }
17    }
18}
19
20impl hash::Hash for BrokenF32 {
21    fn hash<H>(&self, state: &mut H)
22    where
23        H: hash::Hasher,
24    {
25        self.key().hash(state)
26    }
27}
28
29impl PartialEq for BrokenF32 {
30    fn eq(&self, other: &Self) -> bool {
31        self.key() == other.key()
32    }
33}
34
35impl Eq for BrokenF32 {}
aterm/bad_idea.rs

aterm/
bad_idea.rs
