internal RangeLiteral(int ch)
{
list = new RangeList(false);
list.Add(new CharRange(ch, ch)); // AddToRange
}
internal RangeLiteral(bool invert)
{
list = new RangeList(invert);
}
/// <summary>
/// Return a new RangeList that is the intersection of
/// "this" and rhOp. Neither operand is mutated.
/// </summary>
/// <param name="rhOp"></param>
/// <returns></returns>
internal RangeList AND(RangeList rhOp)
{
if (!isCanonical || !rhOp.isCanonical)
{
throw new GplexInternalException("RangeList non canonicalized");
}
if (this.ranges.Count == 0 || rhOp.ranges.Count == 0)
{
return(new RangeList(false)); // return empty RangeList
}
int thisIx;
int rhOpIx = 0;
int thisNm = this.ranges.Count;
int rhOpNm = rhOp.ranges.Count;
List <CharRange> newList = new List <CharRange>();
RangeList result = new RangeList(newList, false);
CharRange rhOpElem = rhOp.ranges[rhOpIx++];
for (thisIx = 0; thisIx < thisNm; thisIx++)
{
CharRange thisElem = this.ranges[thisIx];
// Attempt to find an overlapping element.
// If necessary fetch new elements from rhOp
// until maxChr of the new element is greater
// than minChr of the current thisElem.
while (rhOpElem.maxChr < thisElem.minChr)
{
if (rhOpIx < rhOpNm)
{
rhOpElem = rhOp.ranges[rhOpIx++];
}
else
{
return(result);
}
}
// It is possible that the rhOpElem is entirely beyond thisElem
// It is also possible that rhOpElem and several following
// elements are all overlapping with thisElem.
while (rhOpElem.minChr <= thisElem.maxChr)
{
// process overlap
newList.Add(new CharRange(
(thisElem.minChr < rhOpElem.minChr ? rhOpElem.minChr : thisElem.minChr),
(thisElem.maxChr < rhOpElem.maxChr ? thisElem.maxChr : rhOpElem.maxChr)));
// If rhOpElem extends beyond thisElem.maxChr it is possible that
// it will overlap with the next thisElem, so do not advance rhOpIx.
if (rhOpElem.maxChr > thisElem.maxChr)
{
break;
}
else if (rhOpIx == rhOpNm)
{
return(result);
}
else
{
rhOpElem = rhOp.ranges[rhOpIx++];
}
}
}
return(result);
}
internal PartitionElement(List <CharRange> ranges, bool invert)
{
ord = nextOrd++;
list = new RangeList(ranges, invert);
}
/// <summary>
/// Refine the current partition with respect
/// to the given range literal "lit".
/// </summary>
/// <param name="lit">The Range Literal</param>
internal void Refine(RangeLiteral lit)
{
int idx;
int max = elements.Count; // because this varies inside the loop
//
// For each of the *current* elements of the partition do:
//
for (idx = 0; idx < max; idx++)
{
PartitionElement elem = elements[idx];
RangeList intersection = lit.list.AND(elem.list);
//
// There are four cases here:
// (1) No intersection of lit and elem ... do nothing
// (2) Literal properly contains the partition element ...
// Add this element to the equivClasses list of this lit.
// Add this lit to the list of literals dependent on "elem".
// The intersection of other parts of the literal with other
// elements will be processed by other iterations of the loop.
// (3) Literal is properly contained in the partition element ...
// Split the element into two: a new element containing the
// intersection, and an updated "elem" with the intersection
// subtracted. All literals dependent on the old element are
// now dependent on the new element and (the new version of)
// this element. The literal cannot overlap with any other
// element, so the iteration can be terminated.
// (4) Literal partially overlaps the partition element ...
// Split the element as for case 2. Overlaps of the rest
// of the literal with other elements will be dealt with by
// other iterations of the loop.
//
if (!intersection.IsEmpty) // not empty intersection
{
// Test if elem is properly contained in lit
// If so, intersection == elem ...
if (intersection.EQU(elem.list))
{
elem.literals.Add(lit);
lit.equivClasses.Add(elem.ord);
}
else
{
PartitionElement newElem =
new PartitionElement(intersection.Ranges, false);
elements.Add(newElem);
lit.equivClasses.Add(newElem.ord);
newElem.literals.Add(lit);
//
// We are about to split elem.
// All literals that include elem
// must now also include newElem
//
foreach (RangeLiteral rngLit in elem.literals)
{
rngLit.equivClasses.Add(newElem.ord);
newElem.literals.Add(rngLit);
}
elem.list = elem.list.SUB(intersection);
//
// Test if lit is a subset of elem
// If so, intersection == lit and we can
// assert that no other loop iteration has
// a non-empty intersection with this lit.
//
if (intersection.EQU(lit.list))
{
return;
}
}
}
}
}
