78 lines
2.4 KiB
Zig
78 lines
2.4 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2020 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 integer
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pub fn Int(comptime T: type) type {
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return extern struct {
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unprotected_value: T,
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pub const Self = @This();
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pub fn init(init_val: T) Self {
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return Self{ .unprotected_value = init_val };
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}
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/// Read, Modify, Write
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pub fn rmw(self: *Self, comptime op: builtin.AtomicRmwOp, operand: T, comptime ordering: builtin.AtomicOrder) T {
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return @atomicRmw(T, &self.unprotected_value, op, operand, ordering);
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}
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pub fn load(self: *Self, comptime ordering: builtin.AtomicOrder) T {
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return @atomicLoad(T, &self.unprotected_value, ordering);
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}
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pub fn store(self: *Self, value: T, comptime ordering: builtin.AtomicOrder) void {
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@atomicStore(T, &self.unprotected_value, value, ordering);
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}
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/// Twos complement wraparound increment
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/// Returns previous value
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pub fn incr(self: *Self) T {
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return self.rmw(.Add, 1, .SeqCst);
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}
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/// Twos complement wraparound decrement
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/// Returns previous value
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pub fn decr(self: *Self) T {
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return self.rmw(.Sub, 1, .SeqCst);
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}
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pub fn get(self: *Self) T {
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return self.load(.SeqCst);
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}
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pub fn set(self: *Self, new_value: T) void {
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self.store(new_value, .SeqCst);
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}
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pub fn xchg(self: *Self, new_value: T) T {
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return self.rmw(.Xchg, new_value, .SeqCst);
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}
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/// Twos complement wraparound add
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/// Returns previous value
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pub fn fetchAdd(self: *Self, op: T) T {
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return self.rmw(.Add, op, .SeqCst);
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}
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};
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}
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test "std.atomic.Int" {
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var a = Int(u8).init(0);
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testing.expectEqual(@as(u8, 0), a.incr());
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testing.expectEqual(@as(u8, 1), a.load(.SeqCst));
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a.store(42, .SeqCst);
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testing.expectEqual(@as(u8, 42), a.decr());
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testing.expectEqual(@as(u8, 41), a.xchg(100));
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testing.expectEqual(@as(u8, 100), a.fetchAdd(5));
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testing.expectEqual(@as(u8, 105), a.get());
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a.set(200);
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}
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