dashmap 2.1.0

//! This module is full of hackery and dark magic.
//! Either spend a day fixing it and quietly submit a PR or don't mention it to anybody.

use std::{mem, ptr};

#[inline(always)]
pub const fn ptr_size_bits() -> usize {
    mem::size_of::<usize>() * 8
}

#[inline(always)]
pub fn map_in_place_2<T, U, F: FnOnce(U, T) -> T>(a: (U, &mut T), f: F) {
    unsafe {
        ptr::write(a.1, f(a.0, ptr::read(a.1)));
    }
}

/// # Safety
///
/// Requires that you ensure the reference does not become invalid.
/// The object has to outlive the reference.
#[inline(always)]
pub unsafe fn change_lifetime_const<'a, 'b, T>(x: &'a T) -> &'b T {
    &*(x as *const T)
}

/// # Safety
///
/// Requires that you ensure the reference does not become invalid.
/// The object has to outlive the reference.
#[inline(always)]
pub unsafe fn change_lifetime_mut<'a, 'b, T>(x: &'a mut T) -> &'b mut T {
    &mut *(x as *mut T)
}

/// # Safety
///
/// Make a immutable ref mutable.
/// Not sure we can do this but you have to guarantee it's the only mut ref in existance.
/// It works anyway.
#[allow(clippy::cast_ref_to_mut)]
#[allow(clippy::mut_from_ref)]
#[allow(clippy::needless_lifetimes)]
#[inline(always)]
pub unsafe fn to_mut<'a, T>(x: &'a T) -> &'a mut T {
    &mut *(x as *const T as *mut T)
}