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68 lines
2.6 KiB
68 lines
2.6 KiB
#ifndef PRIORITY_QUEUE_H
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#define PRIORITY_QUEUE_H
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#include "lock.h"
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#include "runtime.h"
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#include "worker_thread.h"
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/**
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* How to get the priority out of the generic element
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* We assume priority is expressed as an unsigned 64-bit integer (i.e. cycles or
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* UNIX time in ms). This is used to maintain a read replica of the highest
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* priority element that can be used to maintain a read replica
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* @param element
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* @returns priority (a uint64_t)
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*/
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typedef uint64_t (*priority_queue_get_priority_fn_t)(void *element);
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/* We assume that priority is expressed in terms of a 64 bit unsigned integral */
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struct priority_queue {
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priority_queue_get_priority_fn_t get_priority_fn;
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bool use_lock;
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lock_t lock;
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uint64_t highest_priority;
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size_t size;
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size_t capacity;
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void * items[];
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};
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/**
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* Peek at the priority of the highest priority task without having to take the lock
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* Because this is a min-heap PQ, the highest priority is the lowest 64-bit integer
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* This is used to store an absolute deadline
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* @returns value of highest priority value in queue or ULONG_MAX if empty
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*/
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static inline uint64_t
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priority_queue_peek(struct priority_queue *self)
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{
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return self->highest_priority;
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}
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struct priority_queue *
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priority_queue_initialize(size_t capacity, bool use_lock, priority_queue_get_priority_fn_t get_priority_fn);
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void priority_queue_free(struct priority_queue *self);
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int priority_queue_length(struct priority_queue *self);
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int priority_queue_length_nolock(struct priority_queue *self);
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int priority_queue_enqueue(struct priority_queue *self, void *value);
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int priority_queue_enqueue_nolock(struct priority_queue *self, void *value);
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int priority_queue_delete(struct priority_queue *self, void *value);
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int priority_queue_delete_nolock(struct priority_queue *self, void *value);
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int priority_queue_dequeue(struct priority_queue *self, void **dequeued_element);
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int priority_queue_dequeue_nolock(struct priority_queue *self, void **dequeued_element);
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int priority_queue_dequeue_if_earlier(struct priority_queue *self, void **dequeued_element, uint64_t target_deadline);
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int priority_queue_dequeue_if_earlier_nolock(struct priority_queue *self, void **dequeued_element,
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uint64_t target_deadline);
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uint64_t priority_queue_peek(struct priority_queue *self);
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int priority_queue_top(struct priority_queue *self, void **dequeued_element);
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int priority_queue_top_nolock(struct priority_queue *self, void **dequeued_element);
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#endif /* PRIORITY_QUEUE_H */
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