NAME
ACE_Timer_Heap_T - Provides a very fast and predictable timer implementation.
SYNOPSIS
#include <ace/Timer_Heap_T.h>
template<class TYPE, class FUNCTOR, class ACE_LOCK>
class ACE_Timer_Heap_T :
public ACE_Timer_Queue_T<TYPE, FUNCTOR, ACE_LOCK>
{
public:
typedef ACE_Timer_Heap_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> HEAP_ITERATOR;
friend class ACE_Timer_Heap_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>;
typedef ACE_Timer_Queue_T<TYPE, FUNCTOR, ACE_LOCK> INHERITED;
ACE_Timer_Heap_T (
size_t size,
int preallocated = 0,
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
ACE_Timer_Heap_T (
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
virtual ~ACE_Timer_Heap_T (void);
virtual int is_empty (void) const;
virtual const ACE_Time_Value &earliest_time (void) const;
virtual long schedule (
const TYPE &type,
const void *act,
const ACE_Time_Value &delay,
const ACE_Time_Value &interval = ACE_Time_Value::zero
);
virtual int reset_interval (
long timer_id,
const ACE_Time_Value &interval
);
virtual int cancel (
const TYPE &type,
int dont_call_handle_close = 1
);
virtual int cancel (
long timer_id,
const void **act = 0,
int dont_call_handle_close = 1
);
virtual ACE_Timer_Queue_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> &iter (
void
);
ACE_Timer_Node_T <TYPE> *remove_first (void);
virtual void dump (void) const;
virtual ACE_Timer_Node_T<TYPE> *get_first (void);
protected:
virtual void reschedule (ACE_Timer_Node_T<TYPE> *);
virtual ACE_Timer_Node_T<TYPE> *alloc_node (void);
virtual void free_node (ACE_Timer_Node_T<TYPE> *);
private:
ACE_Timer_Node_T<TYPE> *remove (size_t slot);
void insert (ACE_Timer_Node_T<TYPE> *new_node);
void grow_heap (void);
void reheap_up (
ACE_Timer_Node_T<TYPE> *new_node,
size_t slot,
size_t parent
);
void reheap_down (
ACE_Timer_Node_T<TYPE> *moved_node,
size_t slot,
size_t child
);
void copy (int slot, ACE_Timer_Node_T<TYPE> *moved_node);
int timer_id (void);
int pop_freelist (void);
void push_freelist (int old_id);
size_t max_size_;
size_t cur_size_;
HEAP_ITERATOR *iterator_;
ACE_Timer_Node_T<TYPE> **heap_;
long *timer_ids_;
long timer_ids_freelist_;
ACE_Timer_Node_T<TYPE> *preallocated_nodes_;
ACE_Timer_Node_T<TYPE> *preallocated_nodes_freelist_;
ACE_Unbounded_Set<ACE_Timer_Node_T<TYPE> *> preallocated_node_set_;
inline ACE_UNIMPLEMENTED_FUNC (
ACE_Timer_Heap_T (const ACE_Timer_Heap_T<TYPE, FUNCTOR, ACE_LOCK> &)
);
};
DESCRIPTION
This implementation uses a heap-based callout queue of absolute times. Therefore, in the average and worst case, scheduling, canceling, and expiring timers is O(log N) (where N is the total number of timers). In addition, we can also preallocate as many ACE_Timer_Nodes as there are slots in the heap. This allows us to completely remove the need for dynamic memory allocation, which is important for real-time systems.
Initialization and termination methods.
ACE_Timer_Heap_T (
size_t size,
int preallocated = 0,
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
The Constructor creates a heap with size elements. If preallocated is non-0 then we'll pre-allocate all the memory for the ACE_Timer_Nodes. This saves time and is more predictable (though it requires more space). Otherwise, we'll just allocate the nodes as we need them. This can also take in a upcall functor and freelist (if 0, then defaults will be created)
ACE_Timer_Heap_T (
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
Default constructor. upcall_functor is the instance of the FUNCTOR to be used by the queue. If upcall_functor is 0, Timer Heap will create a default FUNCTOR. freelist the freelist of timer nodes. If 0, then a default freelist will be created. The default size will be ACE_DEFAULT_TIMERS and there will be no preallocation.
virtual ~ACE_Timer_Heap_T (void);
Destructor.
virtual int is_empty (void) const;
True if heap is empty, else false.
virtual const ACE_Time_Value &earliest_time (void) const;
Returns the time of the earlier node in the Timer_Queue.
virtual long schedule (
const TYPE &type,
const void *act,
const ACE_Time_Value &delay,
const ACE_Time_Value &interval = ACE_Time_Value::zero
);
Schedule type that will expire after delay amount of time, which is specified in absolute time. If it expires then act is passed in as the value to the functor. If interval is != to ACE_Time_Value::zero then it is used to reschedule the type automatically, using relative time to the current gettimeofday. This method returns a timer_id that uniquely identifies the the type entry in an internal list. This timer_id can be used to cancel the timer before it expires. The cancellation ensures that timer_ids are unique up to values of greater than 2 billion timers. As long as timers don't stay around longer than this there should be no problems with accidentally deleting the wrong timer. Returns -1 on failure (which is guaranteed never to be a valid timer_id).
virtual int reset_interval (
long timer_id,
const ACE_Time_Value &interval
);
Resets the interval of the timer represented by timer_id to interval, which is specified in relative time to the current gettimeofday. If interval is equal to ACE_Time_Value::zero, the timer will become a non-rescheduling timer. Returns 0 if successful, -1 if not.
virtual int cancel (const TYPE &type, int dont_call_handle_close = 1);
Cancel all timer associated with type. If dont_call is 0 then the functor will be invoked. Returns number of timers cancelled.
virtual int cancel (
long timer_id,
const void **act = 0,
int dont_call_handle_close = 1
);
Cancel the single timer that matches the timer_id value (which was returned from the schedule method). If act is non-NULL then it will be set to point to the ``magic cookie'' argument passed in when the timer was registered. This makes it possible to free up the memory and avoid memory leaks. If dont_call is 0 then the functor will be invoked. Returns 1 if cancellation succeeded and 0 if the timer_id wasn't found.
virtual ACE_Timer_Queue_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> &iter (
void
);
Returns a pointer to this ACE_Timer_Queue's iterator.
ACE_Timer_Node_T <TYPE> *remove_first (void);
Removes the earliest node from the queue and returns it
virtual void dump (void) const;
Dump the state of an object.
virtual ACE_Timer_Node_T<TYPE> *get_first (void);
Reads the earliest node from the queue and returns it.
Don't allow these operations for now.
inline ACE_UNIMPLEMENTED_FUNC (
ACE_Timer_Heap_T (const ACE_Timer_Heap_T<TYPE, FUNCTOR, ACE_LOCK> &)
);
AUTHOR
Doug Schmidt
LIBRARY
ace