1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121

// This file is part of linux-support. It is subject to the license terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/linux-support/master/COPYRIGHT. No part of linux-support, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file.
// Copyright © 2020 The developers of linux-support. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/linux-support/master/COPYRIGHT.


/// Loads an `Atomic*` (eg `AtomicU8`) non-atomically without any synchronization.
pub trait LoadNonAtomically
{
	/// Non-atomic type.
	type NonAtomic: Sized + Copy;

	/// Loads from, say, an AtomicU32 non-atomically
	fn load_non_atomically(self) -> Self::NonAtomic;
}

macro_rules! load_non_atomically
{
	($atomic_type: ident, $non_atomic_type: ty) =>
	{
		impl<'a> LoadNonAtomically for &'a std::sync::atomic::$atomic_type
		{
			type NonAtomic = $non_atomic_type;

			#[inline(always)]
			fn load_non_atomically(self) -> Self::NonAtomic
			{
				let pointer: *const Self = unsafe { transmute(self) };
				unsafe { pointer.cast::<Self::NonAtomic>().read() }
			}
		}

		impl LoadNonAtomically for std::ptr::NonNull<std::sync::atomic::$atomic_type>
		{
			type NonAtomic = $non_atomic_type;

			#[inline(always)]
			fn load_non_atomically(self) -> Self::NonAtomic
			{
				(unsafe { self.as_ref() }).load_non_atomically()
			}
		}

		impl LoadNonAtomically for *const std::sync::atomic::$atomic_type
		{
			type NonAtomic = $non_atomic_type;

			#[inline(always)]
			fn load_non_atomically(self) -> Self::NonAtomic
			{
				(unsafe { & * self }).load_non_atomically()
			}
		}

		impl LoadNonAtomically for *mut std::sync::atomic::$atomic_type
		{
			type NonAtomic = $non_atomic_type;

			#[inline(always)]
			fn load_non_atomically(self) -> Self::NonAtomic
			{
				(unsafe { & * self }).load_non_atomically()
			}
		}
	}
}

load_non_atomically!(AtomicBool, bool);
load_non_atomically!(AtomicU8, u8);
load_non_atomically!(AtomicU16, u16);
load_non_atomically!(AtomicU32, u32);
load_non_atomically!(AtomicU64, u64);
load_non_atomically!(AtomicUsize, usize);
load_non_atomically!(AtomicI8, i8);
load_non_atomically!(AtomicI16, i16);
load_non_atomically!(AtomicI32, i32);
load_non_atomically!(AtomicI64, i64);
load_non_atomically!(AtomicIsize, isize);

impl<'a, T: 'a> LoadNonAtomically for &'a std::sync::atomic::AtomicPtr<T>
{
	type NonAtomic = *mut T;

	#[inline(always)]
	fn load_non_atomically(self) -> Self::NonAtomic
	{
		let pointer: *const Self = unsafe { transmute(self) };
		unsafe { pointer.cast::<Self::NonAtomic>().read() }
	}
}

impl<'a, T: 'a> LoadNonAtomically for std::ptr::NonNull<std::sync::atomic::AtomicPtr<T>>
{
	type NonAtomic = *mut T;

	#[inline(always)]
	fn load_non_atomically(self) -> Self::NonAtomic
	{
		(unsafe { self.as_ref() }).load_non_atomically()
	}
}

impl<'a, T: 'a> LoadNonAtomically for *const std::sync::atomic::AtomicPtr<T>
{
	type NonAtomic = *mut T;

	#[inline(always)]
	fn load_non_atomically(self) -> Self::NonAtomic
	{
		(unsafe { & * self }).load_non_atomically()
	}
}

impl<'a, T: 'a> LoadNonAtomically for *mut std::sync::atomic::AtomicPtr<T>
{
	type NonAtomic = *mut T;

	#[inline(always)]
	fn load_non_atomically(self) -> Self::NonAtomic
	{
		(unsafe { & * self }).load_non_atomically()
	}
}