compact_bitset 0.1.3

A type for storing fixed-size arrays of booleans densely to optimize space
Documentation 
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use crate::CompactBitset;
use num_traits::{Num, NumCast, PrimInt, ToPrimitive, Unsigned};
use std::{fmt::Debug, mem::size_of, ops::Deref};

#[inline(always)]
fn numcast<T: NumCast>(num: impl Num + ToPrimitive) -> T {
    T::from(num).unwrap()
}

#[derive(Clone)]
pub struct BitRef<'parent, T: PrimInt + Unsigned> {
    pub(crate) parent: &'parent CompactBitset<T>,
    pub(crate) idx: usize,
}

impl<'parent, T: PrimInt + Unsigned> BitRef<'parent, T> {
    pub const BITS: usize = size_of::<T>() * 8;
}

impl<'parent, T: PrimInt + Unsigned> Debug for BitRef<'parent, T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", **self)
    }
}

impl<'parent, T: PrimInt + Unsigned> Deref for BitRef<'parent, T> {
    type Target = bool;

    fn deref(&self) -> &Self::Target {
        if (self.parent.data >> self.idx & numcast(1)) != numcast(0) {
            &true
        } else {
            &false
        }
    }
}

impl<'parent, T: PrimInt + Unsigned> Into<bool> for BitRef<'parent, T> {
    fn into(self) -> bool {
        *self
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq for BitRef<'parent, T> {
    fn eq(&self, other: &Self) -> bool {
        self.deref() == other.deref()
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq<bool> for BitRef<'parent, T> {
    fn eq(&self, other: &bool) -> bool {
        self.deref() == other
    }
}

pub struct BitRefMut<'parent, T: PrimInt + Unsigned> {
    pub(crate) parent: &'parent mut CompactBitset<T>,
    pub(crate) idx: usize,
}

impl<'parent, T: PrimInt + Unsigned> BitRefMut<'parent, T> {
    pub const BITS: usize = size_of::<T>() * 8;

    pub fn set(&mut self, value: impl Into<bool>) {
        let value = value.into();
        let mask: T = numcast(1 << self.idx);
        self.parent.data = (self.parent.data & !mask) | (numcast((value as usize) << self.idx));
    }

    fn as_const(&'parent self) -> BitRef<'parent, T> {
        BitRef::<'parent, T> {
            parent: self.parent as &_,
            idx: self.idx,
        }
    }
}

impl<'parent, T: PrimInt + Unsigned> Debug for BitRefMut<'parent, T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", **self)
    }
}

impl<'parent, T: PrimInt + Unsigned> Deref for BitRefMut<'parent, T> {
    type Target = bool;

    fn deref(&self) -> &Self::Target {
        if *self.as_const().deref() {
            &true
        } else {
            &false
        }
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq for BitRefMut<'parent, T> {
    fn eq(&self, other: &Self) -> bool {
        (**self).eq(other)
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq<bool> for BitRefMut<'parent, T> {
    fn eq(&self, other: &bool) -> bool {
        (**self).eq(other)
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq<BitRef<'parent, T>> for BitRefMut<'parent, T> {
    fn eq(&self, other: &BitRef<'parent, T>) -> bool {
        self.as_const() == *other
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq<BitRef<'parent, T>> for bool {
    fn eq(&self, other: &BitRef<'parent, T>) -> bool {
        other == self
    }
}

impl<'parent, T: PrimInt + Unsigned> PartialEq<BitRefMut<'parent, T>> for bool {
    fn eq(&self, other: &BitRefMut<'parent, T>) -> bool {
        other == self
    }
}