aboutsummaryrefslogtreecommitdiff
path: root/lib/std/atomic/bool.zig
blob: c686fdfae08e4069e88a8ba884dc096d77e36739 (plain)
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
// SPDX-License-Identifier: MIT
// Copyright (c) 2015-2020 Zig Contributors
// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
// The MIT license requires this copyright notice to be included in all copies
// and substantial portions of the software.

const std = @import("std");
const builtin = std.builtin;
const testing = std.testing;

/// Thread-safe, lock-free boolean
pub const Bool = extern struct {
    unprotected_value: bool,

    pub const Self = @This();

    pub fn init(init_val: bool) Self {
        return Self{ .unprotected_value = init_val };
    }

    // xchg is only valid rmw operation for a bool
    /// Atomically modifies memory and then returns the previous value.
    pub fn xchg(self: *Self, operand: bool, comptime ordering: std.builtin.AtomicOrder) bool {
        return @atomicRmw(bool, &self.unprotected_value, .Xchg, operand, ordering);
    }

    pub fn load(self: *Self, comptime ordering: std.builtin.AtomicOrder) bool {
        return @atomicLoad(bool, &self.unprotected_value, ordering);
    }

    pub fn store(self: *Self, value: bool, comptime ordering: std.builtin.AtomicOrder) void {
        @atomicStore(bool, &self.unprotected_value, value, ordering);
    }
};

test "std.atomic.Bool" {
    var a = Bool.init(false);
    testing.expectEqual(false, a.xchg(false, .SeqCst));
    testing.expectEqual(false, a.load(.SeqCst));
    a.store(true, .SeqCst);
    testing.expectEqual(true, a.xchg(false, .SeqCst));
    testing.expectEqual(false, a.load(.SeqCst));
}