portable-atomic 0.3.4

Portable atomic types including support for 128-bit atomics, atomic float, etc.
Documentation
macro_rules! atomic128 {
    ($atomic_type:ident, $int_type:ident) => {
        #[repr(C, align(16))]
        pub(crate) struct $atomic_type {
            v: core::cell::UnsafeCell<$int_type>,
        }

        // Send is implicitly implemented.
        // SAFETY: any data races are prevented by atomic intrinsics.
        unsafe impl Sync for $atomic_type {}

        impl $atomic_type {
            #[inline]
            pub(crate) const fn new(v: $int_type) -> Self {
                Self { v: core::cell::UnsafeCell::new(v) }
            }

            #[inline]
            pub(crate) fn is_lock_free() -> bool {
                Self::is_always_lock_free()
            }
            #[inline]
            pub(crate) const fn is_always_lock_free() -> bool {
                true
            }

            #[inline]
            pub(crate) fn get_mut(&mut self) -> &mut $int_type {
                self.v.get_mut()
            }

            #[inline]
            pub(crate) fn into_inner(self) -> $int_type {
                self.v.into_inner()
            }

            #[inline]
            pub(crate) fn load(&self, order: Ordering) -> $int_type {
                crate::utils::assert_load_ordering(order);
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe { atomic_load(self.v.get().cast(), order) as $int_type }
            }

            #[inline]
            pub(crate) fn store(&self, val: $int_type, order: Ordering) {
                crate::utils::assert_store_ordering(order);
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe { atomic_store(self.v.get().cast(), val as u128, order) }
            }

            #[inline]
            pub(crate) fn swap(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe { atomic_swap(self.v.get().cast(), val as u128, order) as $int_type }
            }

            #[inline]
            pub(crate) fn compare_exchange(
                &self,
                current: $int_type,
                new: $int_type,
                success: Ordering,
                failure: Ordering,
            ) -> Result<$int_type, $int_type> {
                crate::utils::assert_compare_exchange_ordering(success, failure);
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    match atomic_compare_exchange(
                        self.v.get().cast(),
                        current as u128,
                        new as u128,
                        success,
                        failure,
                    ) {
                        Ok(v) => Ok(v as $int_type),
                        Err(v) => Err(v as $int_type),
                    }
                }
            }

            #[inline]
            pub(crate) fn compare_exchange_weak(
                &self,
                current: $int_type,
                new: $int_type,
                success: Ordering,
                failure: Ordering,
            ) -> Result<$int_type, $int_type> {
                crate::utils::assert_compare_exchange_ordering(success, failure);
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    match atomic_compare_exchange_weak(
                        self.v.get().cast(),
                        current as u128,
                        new as u128,
                        success,
                        failure,
                    ) {
                        Ok(v) => Ok(v as $int_type),
                        Err(v) => Err(v as $int_type),
                    }
                }
            }

            #[inline]
            pub(crate) fn fetch_add(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| x.wrapping_add(val as u128))
                        as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_sub(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| x.wrapping_sub(val as u128))
                        as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_and(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| x & val as u128) as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_nand(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| !(x & val as u128)) as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_or(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| x | val as u128) as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_xor(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| x ^ val as u128) as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_max(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| {
                        core::cmp::max(x as $int_type, val) as u128
                    }) as $int_type
                }
            }

            #[inline]
            pub(crate) fn fetch_min(&self, val: $int_type, order: Ordering) -> $int_type {
                // SAFETY: any data races are prevented by atomic intrinsics and the raw
                // pointer passed in is valid because we got it from a reference.
                unsafe {
                    atomic_update(self.v.get().cast(), order, |x| {
                        core::cmp::min(x as $int_type, val) as u128
                    }) as $int_type
                }
            }
        }
    };
}