38 lines
1.1 KiB
Zig
38 lines
1.1 KiB
Zig
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/// Many reader, many writer, non-allocating, thread-safe, lock-free
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pub fn Queue(comptime T: type) type {
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return struct {
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head: &Node,
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tail: &Node,
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root: Node,
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pub const Self = this;
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pub const Node = struct {
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next: ?&Node,
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data: T,
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};
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// TODO: well defined copy elision
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pub fn init(self: &Self) void {
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self.root.next = null;
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self.head = &self.root;
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self.tail = &self.root;
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}
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pub fn put(self: &Self, node: &Node) void {
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node.next = null;
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const tail = @atomicRmw(&Node, &self.tail, AtomicRmwOp.Xchg, node, AtomicOrder.SeqCst);
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_ = @atomicRmw(?&Node, &tail.next, AtomicRmwOp.Xchg, node, AtomicOrder.SeqCst);
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}
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pub fn get(self: &Self) ?&Node {
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var head = @atomicLoad(&Node, &self.head, AtomicOrder.Acquire);
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while (true) {
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const node = head.next ?? return null;
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head = @cmpxchgWeak(&Node, &self.head, head, node, AtomicOrder.Release, AtomicOrder.Acquire) ?? return node;
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}
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}
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};
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}
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