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