56 lines
2.1 KiB
Zig
56 lines
2.1 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2021 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const std = @import("std");
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const builtin = std.builtin;
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const testing = std.testing;
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/// Thread-safe, lock-free boolean
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pub const Bool = extern struct {
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unprotected_value: bool,
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pub const Self = @This();
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pub fn init(init_val: bool) Self {
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return Self{ .unprotected_value = init_val };
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}
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// xchg is only valid rmw operation for a bool
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/// Atomically modifies memory and then returns the previous value.
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pub fn xchg(self: *Self, operand: bool, comptime ordering: std.builtin.AtomicOrder) bool {
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switch (ordering) {
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.Monotonic, .Acquire, .Release, .AcqRel, .SeqCst => {},
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else => @compileError("Invalid ordering '" ++ @tagName(ordering) ++ "' for a RMW operation"),
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}
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return @atomicRmw(bool, &self.unprotected_value, .Xchg, operand, ordering);
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}
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pub fn load(self: *Self, comptime ordering: std.builtin.AtomicOrder) bool {
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switch (ordering) {
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.Unordered, .Monotonic, .Acquire, .SeqCst => {},
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else => @compileError("Invalid ordering '" ++ @tagName(ordering) ++ "' for a load operation"),
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}
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return @atomicLoad(bool, &self.unprotected_value, ordering);
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}
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pub fn store(self: *Self, value: bool, comptime ordering: std.builtin.AtomicOrder) void {
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switch (ordering) {
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.Unordered, .Monotonic, .Release, .SeqCst => {},
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else => @compileError("Invalid ordering '" ++ @tagName(ordering) ++ "' for a store operation"),
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}
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@atomicStore(bool, &self.unprotected_value, value, ordering);
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}
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};
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test "std.atomic.Bool" {
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var a = Bool.init(false);
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testing.expectEqual(false, a.xchg(false, .SeqCst));
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testing.expectEqual(false, a.load(.SeqCst));
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a.store(true, .SeqCst);
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testing.expectEqual(true, a.xchg(false, .SeqCst));
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testing.expectEqual(false, a.load(.SeqCst));
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}
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