public bool Next(int index, Tristate selected)
{
switch (state)
{
case State.Initial:
if (selected.IsYes())
{
state = State.InRun;
runCount = 1;
runStartIndex = index;
}
return(false);
case State.JustAfterRun:
if (selected.IsYes())
{
state = State.InRun;
runCount = 1;
runStartIndex = index;
goto checkCases;
}
else
{
state = State.Initial;
prevRunCount = 0;
runCount = 0;
}
return(false);
case State.InRun:
if (selected.IsYes())
{
state = State.InRun;
runCount += 1;
if (runCount > max)
{
// Immediate contradiction
return(true);
}
goto checkCases;
}
else
{
// Also case 1.
if (runCount == max)
{
if (selected.Possible())
{
banAt(index);
}
}
state = State.JustAfterRun;
prevRunCount = runCount;
runCount = 0;
}
return(false);
}
// Unreachable
throw new Exception("Unreachable");
checkCases:
// Have we entered case 1 or 2?
if (prevRunCount + runCount == max)
{
// Ban on the previous end of the run
if (runStartIndex == 0)
{
if (periodic)
{
banAt(indexCount - 1);
}
}
else
{
banAt(runStartIndex - 1);
}
}
return(false);
}
