Diff: Schedule.h

Revision:

0:03d36a9a088b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Schedule.h	Wed Apr 27 18:00:45 2011 +0000
@@ -0,0 +1,97 @@
+typedef unsigned int tick;
+typedef int value;
+typedef char flag;
+
+/** Simple library for scheduling events by polling time, that is, avoiding interrupts.
+ *  Can schedule up to 64 events.  The schedule is defined by the number of ticks making
+ *  up the initial period of the schedule, and either a start and end value or values
+ *  at specific tick values.
+ */
+class Schedule {
+    public:
+        /** Sets the behavior of getNext() after the initial schedule period has exceeded.
+         *
+         * @param repeat means the schedule values are repeated
+         * @param hold means the last schedule value is provided after the schdule is done
+         */
+        enum { repeat=0x02, hold=0x04 };
+
+        /** Creates an empty schedule
+         */
+        Schedule();
+        
+        /** Creates a schedule based on a linear function. See set()
+         *
+         *  @param scale
+         *  @param max the maximum tick value of the clock, sets the period
+         *  @param start is the value returned at tick == 0 
+         *  @param stop is the value returned at tick == ticks-1
+         *  @param m selects the mode / behavior of the schedule when getNext() called after period exceeded
+         */
+        Schedule(unsigned int scale, tick max, value start, value stop, flag m);
+            
+        /** Sets a ratio of time to ticks. See clockTicked()
+         *
+         * @param timePerTick specifies the number of time units per tick
+         */
+        void scale(unsigned int scale);
+        
+        /** Sets the total number of ticks to run the loop
+         */
+        void max(tick max);
+        
+        /** Sets behavior of getNext() when called after tickCount exceeded
+         */
+        void mode(flag m);
+        
+        /** sets the value at the specified tick
+         *
+         * @param t specifies the scheduled tick
+         * @param v specifies the value to return when tick==whichTick
+         */        
+        void set(tick t, value v);
+        
+        /** Set schedule based on a linear function
+         *
+         *  @param ticks total number of ticks over which the schedule is valid
+         *  @param startValue is the value returned at tick == 0 
+         *  @param stopValue is the value returned at tick == ticks-1
+         */
+        void set(unsigned int scale, tick max, value start, value stop, flag m); 
+        
+        /** get the next value for schedule's current time.  Use with ticked()
+         *
+         * @returns the value at the current schedule's time
+         */
+        value get();
+        
+        /** increment the clock and get the next value in the schedule
+         *
+         * @returns the value at the schedule's next clock tick
+         */
+         value next();
+         
+        /** Pass in some unit of time and determine if the 'clock' has ticked.
+         *  Suppose timePerTick == 20 and you pass in the elapsed time in milliseconds
+         *  then this function returns true every 20ms.
+         *
+         *  @param time the integer corresponding to elapsed time
+         *  @returns true if the elapsed time % timePerTick == 0
+         */
+        bool ticked(unsigned int time);
+        
+        /** Are we done with the schedule?
+         *
+         * @returns true if schedule is done; see max()
+         */
+        bool done();
+
+    private:
+        unsigned int _scale;
+        tick _max;
+        tick _clock;
+        flag _mode;
+        int _schedule[64];
+        bool _validTick(tick t);
+};
+        
\ No newline at end of file