queue.h File Reference

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Data Structures
struct	qnode

Macros
#define	queue_free(q)

Typedefs
typedef struct qnode	qnode_t
typedef qnode_t	q_t

Functions
q_t *	queue_init (void)
void	queue_destroy (q_t *q, void(*callback)(void *))
qnode_t *	enqueue (q_t *q, void *data)
qnode_t *	prequeue (q_t *q, void *data)
qnode_t *	queue_move_to_tail (q_t *q, qnode_t *nodenode)
	Move existing node to tail (MRU) without reallocation.
qnode_t *	queue_move_to_tail_of (q_t *from_q, q_t *to_q, qnode_t *nodenode)
	Move node from one queue to another without memory reallocation.
void *	dequeue (q_t *q)

Macro Definition Documentation

queue_free

#define queue_free

(

q

)

Value:

queue_destroy((q), free)

Typedef Documentation

q_t

typedef qnode_t q_t

qnode_t

typedef struct qnode qnode_t

Function Documentation

dequeue()

void * dequeue ( q_t * q )

extern

Take from head

enqueue()

qnode_t * enqueue ( q_t * q, void * data )

extern

Insert at tail

prequeue()

qnode_t * prequeue ( q_t * q, void * data )

extern

Insert at head

queue_destroy()

void queue_destroy ( q_t * q, void(* callback )(void *) )

extern

queue_init()

q_t * queue_init ( void )

extern

queue_move_to_tail()

qnode_t * queue_move_to_tail ( q_t * q, qnode_t * node )

extern

Move existing node to tail (MRU) without reallocation.

This function provides O(1) move-to-tail operation without malloc/free overhead. Used by ARC cache to efficiently update T2 on cache hits.

Parameters

[in]	q	Queue (circular doubly-linked list with sentinel)
[in]	node	Node to move to tail (must currently be in queue q)

Returns

The same node pointer (now at tail/MRU), or NULL on error

Note

The node pointer remains valid and unchanged - only its position changes

If node is already at tail, this is a no-op (fast path)

This is thread-safe if external locking is used (same as other queue ops)

queue_move_to_tail_of()

qnode_t * queue_move_to_tail_of ( q_t * from_q, q_t * to_q, qnode_t * node )

extern

Move node from one queue to another without memory reallocation.

Removes node from source queue and adds it to tail of destination queue. The node pointer remains valid and unchanged - enables zero-allocation transitions between ARC lists (T1→T2, T1→B1, T2→B2, B1→T2, B2→T2).

Parameters

[in]	from_q	Source queue (node must be in this queue)
[in]	to_q	Destination queue
[in]	node	Node to move

Returns

The same node pointer (now in dest queue), or NULL on error