The timer scheduling implementation here is based on ACE library's ACE_Timer_Heap, with only little modification to suit our library's style (I even left most of the comments in the original source). More...

Data Structures
struct	pj_timer_entry

Typedefs
typedef int	pj_timer_id_t

typedef void	pj_timer_heap_callback(pj_timer_heap_t timer_heap, struct pj_timer_entry entry)

Functions
pj_size_t	pj_timer_heap_mem_size (pj_size_t count)

pj_status_t	pj_timer_heap_create (pj_pool_t pool, pj_size_t count, pj_timer_heap_t *ht)

void	pj_timer_heap_destroy (pj_timer_heap_t *ht)

void	pj_timer_heap_set_lock (pj_timer_heap_t ht, pj_lock_t lock, pj_bool_t auto_del)

unsigned	pj_timer_heap_set_max_timed_out_per_poll (pj_timer_heap_t *ht, unsigned count)

pj_timer_entry *	pj_timer_entry_init (pj_timer_entry entry, int id, void user_data, pj_timer_heap_callback *cb)

pj_bool_t	pj_timer_entry_running (pj_timer_entry *entry)

pj_status_t	pj_timer_heap_schedule (pj_timer_heap_t ht, pj_timer_entry entry, const pj_time_val *delay)

pj_status_t	pj_timer_heap_schedule_w_grp_lock (pj_timer_heap_t ht, pj_timer_entry entry, const pj_time_val delay, int id_val, pj_grp_lock_t grp_lock)

int	pj_timer_heap_cancel (pj_timer_heap_t ht, pj_timer_entry entry)

int	pj_timer_heap_cancel_if_active (pj_timer_heap_t ht, pj_timer_entry entry, int id_val)

pj_size_t	pj_timer_heap_count (pj_timer_heap_t *ht)

pj_status_t	pj_timer_heap_earliest_time (pj_timer_heap_t ht, pj_time_val timeval)

unsigned	pj_timer_heap_poll (pj_timer_heap_t ht, pj_time_val next_delay)

Detailed Description

The timer scheduling implementation here is based on ACE library's ACE_Timer_Heap, with only little modification to suit our library's style (I even left most of the comments in the original source).

To quote the original quote in ACE_Timer_Heap_T class:

 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 \a 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.

You can find the fine ACE library at: http://www.cs.wustl.edu/~schmidt/ACE.html

Examples

For some examples on how to use the timer heap, please see the link below.

Test: Timer

Typedef Documentation

◆ pj_timer_heap_callback

typedef void pj_timer_heap_callback(pj_timer_heap_t *timer_heap, struct pj_timer_entry *entry)

The type of callback function to be called by timer scheduler when a timer has expired.

Parameters

timer_heap	The timer heap.
entry	Timer entry which timer's has expired.

◆ pj_timer_id_t

typedef int pj_timer_id_t

The type for internal timer ID.

Function Documentation

◆ pj_timer_entry_init()

pj_timer_entry * pj_timer_entry_init	(	pj_timer_entry *	entry,
		int	id,
		void *	user_data,
		pj_timer_heap_callback *	cb
	)

Initialize a timer entry. Application should call this function at least once before scheduling the entry to the timer heap, to properly initialize the timer entry.

Parameters

entry	The timer entry to be initialized.
id	Arbitrary ID assigned by the user/owner of this entry. Applications can use this ID to distinguish multiple timer entries that share the same callback and user_data.
user_data	User data to be associated with this entry. Applications normally will put the instance of object that owns the timer entry in this field.
cb	Callback function to be called when the timer elapses.

Returns: The timer entry itself.

◆ pj_timer_entry_running()

pj_bool_t pj_timer_entry_running ( pj_timer_entry * entry )

Queries whether a timer entry is currently running.

Parameters

entry The timer entry to query.

Returns: PJ_TRUE if the timer is running. PJ_FALSE if not.

◆ pj_timer_heap_cancel()

int pj_timer_heap_cancel	(	pj_timer_heap_t *	ht,
		pj_timer_entry *	entry
	)

Cancel a previously registered timer. This will also decrement the reference counter of the group lock associated with the timer entry, if the entry was scheduled with one.

Parameters

ht	The timer heap.
entry	The entry to be cancelled.

Returns: The number of timer cancelled, which should be one if the entry has really been registered, or zero if no timer was cancelled.

◆ pj_timer_heap_cancel_if_active()

int pj_timer_heap_cancel_if_active	(	pj_timer_heap_t *	ht,
		pj_timer_entry *	entry,
		int	id_val
	)

Cancel only if the previously registered timer is active. This will also decrement the reference counter of the group lock associated with the timer entry, if the entry was scheduled with one. In any case, set the "id" to the specified value.

Parameters

ht	The timer heap.
entry	The entry to be cancelled.
id_val	Value to be set to "id"

Returns: The number of timer cancelled, which should be one if the entry has really been registered, or zero if no timer was cancelled.

◆ pj_timer_heap_count()

pj_size_t pj_timer_heap_count ( pj_timer_heap_t * ht )

Get the number of timer entries.

Parameters

ht	The timer heap.

Returns: The number of timer entries.

◆ pj_timer_heap_create()

pj_status_t pj_timer_heap_create	(	pj_pool_t *	pool,
		pj_size_t	count,
		pj_timer_heap_t **	ht
	)

Create a timer heap.

Parameters

pool	The pool where allocations in the timer heap will be allocated. The timer heap will dynamicly allocate more storate from the pool if the number of timer entries registered is more than the size originally requested when calling this function.
count	The maximum number of timer entries to be supported initially. If the application registers more entries during runtime, then the timer heap will resize.
ht	Pointer to receive the created timer heap.

Returns: PJ_SUCCESS, or the appropriate error code.

◆ pj_timer_heap_destroy()

void pj_timer_heap_destroy ( pj_timer_heap_t * ht )

Destroy the timer heap.

Parameters

ht	The timer heap.

◆ pj_timer_heap_earliest_time()

pj_status_t pj_timer_heap_earliest_time	(	pj_timer_heap_t *	ht,
		pj_time_val *	timeval
	)

Get the earliest time registered in the timer heap. The timer heap MUST have at least one timer being scheduled (application should use pj_timer_heap_count() before calling this function).

Parameters

ht	The timer heap.
timeval	The time deadline of the earliest timer entry.

Returns: PJ_SUCCESS, or PJ_ENOTFOUND if no entry is scheduled.

◆ pj_timer_heap_mem_size()

pj_size_t pj_timer_heap_mem_size ( pj_size_t count )

Calculate memory size required to create a timer heap.

Parameters

count Number of timer entries to be supported.

Returns: Memory size requirement in bytes.

◆ pj_timer_heap_poll()

unsigned pj_timer_heap_poll	(	pj_timer_heap_t *	ht,
		pj_time_val *	next_delay
	)

Poll the timer heap, check for expired timers and call the callback for each of the expired timers.

Note: polling the timer heap is not necessary in Symbian. Please see Symbian OS Specific for more info.

Parameters

ht	The timer heap.
next_delay	If this parameter is not NULL, it will be filled up with the time delay until the next timer elapsed, or PJ_MAXINT32 in the sec part if no entry exist.

Returns: The number of timers expired.

◆ pj_timer_heap_schedule()

pj_status_t pj_timer_heap_schedule	(	pj_timer_heap_t *	ht,
		pj_timer_entry *	entry,
		const pj_time_val *	delay
	)

Schedule a timer entry which will expire AFTER the specified delay.

Parameters

ht	The timer heap.
entry	The entry to be registered.
delay	The interval to expire.

Returns: PJ_SUCCESS, or the appropriate error code.

◆ pj_timer_heap_schedule_w_grp_lock()

pj_status_t pj_timer_heap_schedule_w_grp_lock	(	pj_timer_heap_t *	ht,
		pj_timer_entry *	entry,
		const pj_time_val *	delay,
		int	id_val,
		pj_grp_lock_t *	grp_lock
	)

Schedule a timer entry which will expire AFTER the specified delay, and increment the reference counter of the group lock while the timer entry is active. The group lock reference counter will automatically be released after the timer callback is called or when the timer is cancelled.

Parameters

ht	The timer heap.
entry	The entry to be registered.
delay	The interval to expire.
id_val	The value to be set to the "id" field of the timer entry once the timer is scheduled.
grp_lock	The group lock.

Returns: PJ_SUCCESS, or the appropriate error code.

◆ pj_timer_heap_set_lock()

void pj_timer_heap_set_lock	(	pj_timer_heap_t *	ht,
		pj_lock_t *	lock,
		pj_bool_t	auto_del
	)

Set lock object to be used by the timer heap. By default, the timer heap uses dummy synchronization.

Parameters

ht	The timer heap.
lock	The lock object to be used for synchronization.
auto_del	If nonzero, the lock object will be destroyed when the timer heap is destroyed.

◆ pj_timer_heap_set_max_timed_out_per_poll()

unsigned pj_timer_heap_set_max_timed_out_per_poll	(	pj_timer_heap_t *	ht,
		unsigned	count
	)

Set maximum number of timed out entries to process in a single poll.

Parameters

ht	The timer heap.
count	Number of entries.

Returns: The old number.

Data Structures

Typedefs

Functions

Detailed Description

Examples

Typedef Documentation

◆ pj_timer_heap_callback

◆ pj_timer_id_t

Function Documentation

◆ pj_timer_entry_init()

◆ pj_timer_entry_running()

◆ pj_timer_heap_cancel()

◆ pj_timer_heap_cancel_if_active()

◆ pj_timer_heap_count()

◆ pj_timer_heap_create()

◆ pj_timer_heap_destroy()

◆ pj_timer_heap_earliest_time()

◆ pj_timer_heap_mem_size()

◆ pj_timer_heap_poll()

◆ pj_timer_heap_schedule()

◆ pj_timer_heap_schedule_w_grp_lock()

◆ pj_timer_heap_set_lock()

◆ pj_timer_heap_set_max_timed_out_per_poll()