private static IEnumerable <BigIntRange> EnumerateIncludedRanges(IEnumerable <BigIntRangeBound> sortedBounds)
{
BigInteger?prevBound = null; //only non-null when the previous bound is incomplete and needs the next bound before anything can be returned
foreach (var bound in sortedBounds)
{
if (bound.Direction == Direction.Nowhere)
{
if (prevBound != null)
{
throw new InvalidOperationException("Underlying sorted set of range bounds is corrupt - previous bound (at value " + prevBound.Value + ") expected a matching closing bound next but current bound (at value " + bound.Bound + ") represents a single point.");
}
yield return(BigIntRange.Single(bound.Bound));
}
else if (bound.Direction == Direction.Up)
{
if (prevBound != null)
{
throw new InvalidOperationException("Underlying sorted set of range bounds is corrupt - previous bound (at value " + prevBound.Value + ") expected a matching closing bound next but current bound (at value " + bound.Bound + ") represents the start of a new range.");
}
prevBound = bound.Bound;
}
else
{
if (prevBound == null)
{
throw new InvalidOperationException("Underlying sorted set of range bounds is corrupt - current bound (at value " + bound.Bound + ") represents the end of a range, but the previous bound was a complete range or there was no previous bound");
}
yield return(BigIntRange.CreateStartEnd(prevBound.Value, bound.Bound));
prevBound = null;
}
}
}
public bool TryGetSurroundingRange(BigInteger x, out BigIntRange range, out bool rangeIsIncluded)
{
BigIntRangeBound below;
BigIntRangeBound above;
if (TryGetSurroundingBounds(x, out below, out above))
{
switch (below.Direction)
{
case Direction.Nowhere:
range = BigIntRange.Single(below.Bound); //below == above
rangeIsIncluded = true;
return(true);
case Direction.Down:
switch (above.Direction)
{
case Direction.Down: throw new InvalidOperationException(
"Underlying sorted set of range bounds is corrupt - the bound below or equal to " + nameof(x) + "=" + x + " "
+ "(at value " + below.Bound + ") represents the end of a range, but the bound above or equal "
+ "to " + nameof(x) + "=" + x + " (at value " + above.Bound + ") also represents the end of a range, meaning "
+ "this second range would have no starting value."
);
case Direction.Nowhere: //Same behaviour as for Direction.Up
case Direction.Up:
if (BigInteger.Abs(below.Bound - above.Bound) >= 2) //If there is a gap between the bounds
{
range = BigIntRange.CreateStartEnd(below.Bound + 1, above.Bound - 1);
rangeIsIncluded = false;
return(true);
}
else
{
range = default(BigIntRange);
rangeIsIncluded = default(bool);
return(false);
}
default: break;
}
break;
case Direction.Up:
switch (above.Direction)
{
case Direction.Nowhere: throw new InvalidOperationException(
"Underlying sorted set of range bounds is corrupt - the bound below or equal to " + nameof(x) + "=" + x + " "
+ "(at value " + below.Bound + ") represents the start of a range, so and end to this range is expected next, "
+ "but the bound above or equal to " + nameof(x) + "=" + x + " (at value " + above.Bound + ") represents a range "
+ "containing only single value."
);
case Direction.Up: throw new InvalidOperationException(
"Underlying sorted set of range bounds is corrupt - the bound below or equal to " + nameof(x) + "=" + x + " "
+ "(at value " + below.Bound + ") represents the end of a range, so and end to this range is expected next, "
+ "but the bound above or equal to " + nameof(x) + "=" + x + " (at value " + above.Bound + ") represents "
+ "the start of another range."
);
case Direction.Down:
range = BigIntRange.CreateStartEnd(below.Bound, above.Bound);
rangeIsIncluded = true;
return(true);
default: break;
}
break;
default: break;
}
}
range = default(BigIntRange);
rangeIsIncluded = default(bool);
return(false);
}