--- /dev/null
+package net.mograsim.logic.core.timeline;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.PriorityQueue;
+import java.util.function.BooleanSupplier;
+import java.util.function.Consumer;
+import java.util.function.LongSupplier;
+
+/**
+ * Orders Events by the time they are due to be executed. Can execute Events individually.
+ *
+ * @author Fabian Stemmler
+ *
+ */
+public class Timeline
+{
+ private PriorityQueue<InnerEvent> events;
+ private LongSupplier time;
+ private long lastTimeUpdated = 0;
+
+ private final List<Consumer<TimelineEvent>> eventAddedListener;
+
+ public Timeline(int initCapacity)
+ {
+ events = new PriorityQueue<InnerEvent>(initCapacity);
+
+ eventAddedListener = new ArrayList<>();
+ time = () -> lastTimeUpdated;
+ }
+
+ /**
+ * @param timestamp exclusive
+ * @return true if the first event is later than the timestamp
+ */
+ public BooleanSupplier laterThan(long timestamp)
+ {
+ return () -> timeCmp(events.peek().getTiming(), timestamp) > 0;
+ }
+
+ public boolean hasNext()
+ {
+ return !events.isEmpty();
+ }
+
+ /**
+ * Executes all events at the next timestamp, at which there are any
+ */
+ public void executeNext()
+ {
+ InnerEvent first = events.peek();
+ if (first != null)
+ executeUntil(laterThan(first.getTiming()), -1);
+ }
+
+ public void executeAll()
+ {
+ while (hasNext())
+ executeNext();
+ }
+
+ /**
+ * Executes all events until a given condition is met. The simulation process can be constrained by a real world timestamp.
+ *
+ * @param condition the condition until which the events are be processed
+ * @param stopMillis the System.currentTimeMillis() when simulation definitely needs to stop. A value of -1 means no timeout.
+ * @return State of the event execution
+ * @formatter:off
+ * <code>NOTHING_DONE</code> if the {@link Timeline} was already empty
+ * <code>EXEC_OUT_OF_TIME</code> if the given maximum time was reached
+ * <code>EXEC_UNTIL_CONDITION</code> if the condition was met
+ * <code>EXEC_UNTIL_EMPTY</code> if events were executed until the {@link Timeline} was empty
+ * @formatter:on
+ * @author Christian Femers, Fabian Stemmler
+ */
+ public ExecutionResult executeUntil(BooleanSupplier condition, long stopMillis)
+ {
+ if (events.isEmpty())
+ {
+ lastTimeUpdated = getSimulationTime();
+ return ExecutionResult.NOTHING_DONE;
+ }
+ int checkStop = 0;
+ InnerEvent first = events.peek();
+ while (hasNext() && !condition.getAsBoolean())
+ {
+ events.remove();
+ lastTimeUpdated = first.getTiming();
+ first.run();
+ // Don't check after every run
+ checkStop = (checkStop + 1) % 10;
+ if (checkStop == 0 && System.currentTimeMillis() >= stopMillis)
+ return ExecutionResult.EXEC_OUT_OF_TIME;
+ first = events.peek();
+ }
+ lastTimeUpdated = getSimulationTime();
+ return hasNext() ? ExecutionResult.EXEC_UNTIL_EMPTY : ExecutionResult.EXEC_UNTIL_CONDITION;
+ }
+
+ public void setTimeFunction(LongSupplier time)
+ {
+ this.time = time;
+ }
+
+ public long getSimulationTime()
+ {
+ return time.getAsLong();
+ }
+
+ public long nextEventTime()
+ {
+ if (!hasNext())
+ return -1;
+ return events.peek().getTiming();
+ }
+
+ public void reset()
+ {
+ events.clear();
+ lastTimeUpdated = 0;
+ }
+
+ public void addEventAddedListener(Consumer<TimelineEvent> listener)
+ {
+ eventAddedListener.add(listener);
+ }
+
+ public void removeEventAddedListener(Consumer<TimelineEvent> listener)
+ {
+ eventAddedListener.remove(listener);
+ }
+
+ /**
+ * Adds an Event to the {@link Timeline}
+ *
+ * @param function The {@link TimelineEventHandler} that will be executed, when the {@link InnerEvent} occurs on the timeline.
+ * @param relativeTiming The amount of MI ticks in which the {@link InnerEvent} is called, starting from the current time.
+ */
+ public void addEvent(TimelineEventHandler function, int relativeTiming)
+ {
+ long timing = getSimulationTime() + relativeTiming;
+ TimelineEvent event = new TimelineEvent(timing);
+ events.add(new InnerEvent(function, event));
+ eventAddedListener.forEach(l -> l.accept(event));
+ }
+
+ private class InnerEvent implements Runnable, Comparable<InnerEvent>
+ {
+ private final TimelineEventHandler function;
+ private final TimelineEvent event;
+
+ /**
+ * Creates an {@link InnerEvent}
+ *
+ * @param function {@link TimelineEventHandler} to be executed when the {@link InnerEvent} occurs
+ * @param timing Point in the MI simulation {@link Timeline}, at which the {@link InnerEvent} is executed;
+ */
+ InnerEvent(TimelineEventHandler function, TimelineEvent event)
+ {
+ this.function = function;
+ this.event = event;
+ }
+
+ public long getTiming()
+ {
+ return event.getTiming();
+ }
+
+ @Override
+ public void run()
+ {
+ function.handle(event);
+ }
+
+ @Override
+ public String toString()
+ {
+ return event.toString();
+ }
+
+ @Override
+ public int compareTo(InnerEvent o)
+ {
+ return timeCmp(getTiming(), o.getTiming());
+ }
+ }
+
+ public static int timeCmp(long a, long b)
+ {
+ return Long.signum(a - b);
+ }
+
+ @Override
+ public String toString()
+ {
+ return String.format("Simulation time: %s, Last update: %d, Events: %s", getSimulationTime(), lastTimeUpdated, events.toString());
+ }
+
+ public enum ExecutionResult
+ {
+ NOTHING_DONE, EXEC_UNTIL_EMPTY, EXEC_UNTIL_CONDITION, EXEC_OUT_OF_TIME
+ }
+}
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