/// <summary>
/// A pairwise invariant for a list of elements.
/// </summary>
/// <param name="list">The list.</param>
/// <param name="f">The pairwise invariant.</param>
/// <returns>A zen value for the invariant.</returns>
internal static Zen <bool> PairwiseInvariant <T>(Zen <IList <T> > list, Func <Zen <T>, Zen <T>, Zen <bool> > f)
{
return(list.Case(
empty: true,
cons: (hd1, tl1) => tl1.Case(
empty: true,
cons: (hd2, tl2) => And(f(hd1, hd2), PairwiseInvariant(tl1, f)))));
}
/// <summary>
/// Ensure all storms are ended.
/// </summary>
/// <param name="es">The events.</param>
/// <param name="isPreviousStart">Whether a start is open and waiting to be closed.</param>
/// <param name="priorityClass">The priority class.</param>
/// <returns></returns>
private static Zen <bool> AreStartEndStormsValid(Zen <IList <Event> > es, Zen <bool> isPreviousStart, byte priorityClass)
{
var startType = Event.EventTypeAsByte(EventType.PfcStormStartEvent);
var endType = Event.EventTypeAsByte(EventType.PfcStormEndEvent);
return(es.Case(empty: Not(isPreviousStart), cons: (hd, tl) =>
{
var isCorrectPriority = hd.GetPriorityClass() == priorityClass;
var isStart = And(hd.GetEventType() == startType, isCorrectPriority);
var isEnd = And(hd.GetEventType() == endType, isCorrectPriority);
var isEvent = Or(isStart, isEnd);
var isInvalid = Or(And(isPreviousStart, isStart), And(Not(isPreviousStart), isEnd));
var previousStart = If(isStart, true, If(isEnd, false, isPreviousStart));
return And(Not(isInvalid), AreStartEndStormsValid(tl, previousStart, priorityClass));
}));
}
static Zen <ushort> IsolatedCheckHelper(Zen <IList <bool> > list, Zen <ushort> index, Zen <ushort> quota)
{
return(list.Case(
empty: index,
cons: (hd, tl) => If(Not(hd), IsolatedCheckHelper(tl, index, quota), If(quota > 0, IsolatedCheckHelper(tl, index, quota - 1), ushort.MaxValue))));
}
