51 lines
858 B
C
51 lines
858 B
C
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#include "lfmpscq.h"
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#include "foundation/atomics.h"
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void mpscq_init(mpscq_t* self)
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{
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self->head = &self->stub;
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self->tail = &self->stub;
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self->stub.Next = 0;
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}
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int mpscq_push(mpscq_t *self, queue_node_t *n)
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{
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queue_node_t *prev;
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n->Next = 0;
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prev = nx_atomic_swap_pointer(n, (void * volatile *)&self->head);
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//(*)
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prev->Next = n;
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return prev!=&self->stub;
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}
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queue_node_t *mpscq_pop(mpscq_t *self)
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{
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queue_node_t* tail = self->tail;
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queue_node_t* next = tail->Next;
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queue_node_t* head;
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if (tail == &self->stub)
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{
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if (0 == next)
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return 0;
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self->tail = next;
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tail = next;
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next = next->Next;
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}
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if (next)
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{
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self->tail = next;
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return tail;
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}
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head = self->head;
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if (tail != head)
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return (queue_node_t *)1;
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mpscq_push(self, &self->stub);
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next = tail->Next;
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if (next)
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{
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self->tail = next;
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return tail;
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}
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return 0;
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}
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