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/* Timer.h
* * Copyright (c) 1993-1995 by DataBeam Corporation, Lexington, KY * * Abstract: * This class maintains the current time and dispathes function calls * when timers expire. If a routine wants to be called in X amount of * time, it creates a timer event with this class. When the time expires, * the function is called. If the user wants to cancel the timer before * it expires, he can use the DeleteTimerEvent() function. * * When a person creates a timer event, one of the parameters is the * control flags. The user can set the flag so that the event is a * one-time thing or a constant event that occurs every X milliseconds. * * This timer has a millisecond granularity. The time passed into the * CreateEventTimer() function is assumed to be in milliseconds. * * The ProcessTimerEvents() function must be called frequently and * regularly so that the timeouts occur promptly. * * Caveats: * None. * * Author: * James P. Galvin * James W. Lawwill */#ifndef _TIMER_
#define _TIMER_
/*
** Possible Error values*/typedef enum{ TIMER_NO_ERROR, TIMER_NO_TIMERS_AVAILABLE, TIMER_NO_TIMER_MEMORY, TIMER_INVALID_TIMER_HANDLE} TimerError, * PTimerError;
/*
** These defines are used in the control_flags variable in the TimerEvent** structure. TIMER_EVENT_IN_USE is a flag used internal to the timer** procedure. TIMER_EVENT_ONE_SHOT can be passed in by the user to ** signify that the timer should only occur once.*/#define TIMER_EVENT_IN_USE 0x0001
#define TIMER_EVENT_ONE_SHOT 0x0002
#define TRANSPORT_HASHING_BUCKETS 3
typedef USHORT TimerEventHandle;typedef TimerEventHandle *PTimerEventHandle;
typedef void (IObject::*PTimerFunction) (TimerEventHandle);
/*
** Each timer event has a TimerEvent structure associated with it.*/typedef struct TimerEventStruct{ TimerEventHandle event_handle; ULong timer_duration; ULong total_duration; IObject *object_ptr; PTimerFunction timer_func_ptr; USHORT control_flags; TimerEventStruct *next_timer_event; TimerEventStruct *previous_timer_event;} TimerEvent, * PTimerEvent;
class Timer{ public: Timer ( Void); ~Timer ( Void); TimerEventHandle CreateTimerEvent ( ULong timer_duration, USHORT control_flags, IObject * object_ptr, PTimerFunction timer_function); TimerError DeleteTimerEvent ( TimerEventHandle timer_event); Void ProcessTimerEvents ( Void);
private: USHORT Maximum_Timer_Events; USHORT Timer_Event_Count; SListClass Timer_Event_Free_Stack; PTimerEvent First_Timer_Event_In_Chain; DWORD Last_Timer_Value; DictionaryClass Timer_List;};typedef Timer * PTimer;
extern PTimer System_Timer;
#define InstallTimerEvent(duration, control, func) \
(g_pSystemTimer->CreateTimerEvent((duration),(control),this,(PTimerFunction)(func)))
#endif
/*
* Timer (Void) * * Functional Description: * This is the constructor for the timer class. This procedure gets * thc current Windows system time. * * Formal Parameters: * None * * Return Value: * None * * Side Effects: * None * * Caveats: * None */
/*
* ~Timer (Void) * * Functional Description: * This is the destructor for the timer class. This routine frees all * memory associated with timer events. * * Formal Parameters: * None * * Return Value: * None * * Side Effects: * None * * Caveats: * None */
/*
* TimerEventHandle CreateTimerEvent ( * ULong timer_duration, * USHORT control_flags, * IObject * object_ptr, * PTimerFunction timer_function); * * Functional Description: * This routine is called to create a timer event. The routine stores the * information passed-in in a TimerEvent structure. When the timer expires * the function will be called. * * Formal Parameters: * timer_duration - (i) Amount of time to wait before calling the * function. The granularity of the timer * is milliseconds. * control_flags - (i) This is a USHORT but currently we only * look at one of the bits. The * TIMER_EVENT_ONE_SHOT can be passed-in by * the user if they only want this timeout * to occur once. If this value is 0, the * event will occur time after time. * object_ptr - (i) This is the data address of the object. It * is the 'this' pointer of the calling object. * timer_function - (i) This is the address of the function to * call after the timer expires. * * Return Value: * TimerEventHandle - This is a handle to the timer event. If you * need to delete the timer event, pass this * handle to the DeleteTimer() function. A NULL * handle is returned if the create failed. * * Side Effects: * None * * Caveats: * None */
/*
* TimerError DeleteTimerEvent (TimerEventHandle timer_event) * * Functional Description: * This routine is called by the user to delete a timer event that is * currently active. * * Formal Parameters: * timer_event - (i) Handle to a timer event * * Return Value: * TIMER_NO_ERROR - Successful Delete * TIMER_NO_TIMER_MEMORY - The timer_event can't exist because * there was never any Timer memory * TIMER_INVALID_TIMER_HANDLE - timer_event is not in our list * of timers * * Side Effects: * None * * Caveats: * None */
/*
* Void ProcessTimerEvents (Void) * * Functional Description: * This routine MUST be called frequently and regularly so that we can * manage our timers. This function gets the current system time and * goes through each of the timers to see which have expired. If a timer * has expired, we call the function associated with it. Upon return, * if the timer was marked as a one-shot event, we remove it from our * list of timers. * * Formal Parameters: * None * * Return Value: * None * * Side Effects: * None * * Caveats: * None */
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