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