public static IPRanges Negate(IPRange r1, IPRanges negatedRanges)
{
if (!r1.IsValid())
{
return(null);
}
// merge subnets to negate
var mergedNegatedRanges = Merge(negatedRanges).Ranges;
var res = new List <IPRange>();
// no overlap
if (r1.Maximum < mergedNegatedRanges[0].Minimum || r1.Minimum > mergedNegatedRanges.Last().Maximum)
{
res.Add(r1);
return(new IPRanges(res));
}
var lastRange = new IPRange(r1.Minimum, r1.Maximum);
foreach (IPRange negatedRange in mergedNegatedRanges)
{
if (lastRange.Minimum < negatedRange.Minimum)
{
res.Add(new IPRange(lastRange.Minimum, negatedRange.Minimum - 1));
lastRange.Minimum = negatedRange.Maximum + 1;
}
else
{
if (negatedRange.Maximum < lastRange.Minimum)
{
// do nothing - ignore this range
}
else
{
if (negatedRange.Maximum < lastRange.Maximum)
{
lastRange.Minimum = negatedRange.Maximum + 1;
}
}
}
}
if (!lastRange.IsEmpty())
{
res.Add(lastRange);
}
return(new IPRanges(res));
}
public static IPRanges Merge(IPRanges rangesToMerge)
{
if (rangesToMerge.Ranges.Count == 1)
{
return(new IPRanges(rangesToMerge.Ranges));
}
var mergedRanges = new List <IPRange>();
var rangesToMergeSorted = rangesToMerge.Ranges.OrderBy(o => o.Minimum).ThenBy(y => y.Maximum).ToList();
IPRange rangeA = rangesToMergeSorted[0].Copy();
IPRange rangeB = new IPRange();
bool addA = false;
bool addB = false;
for (int i = 1; i < rangesToMergeSorted.Count; i++)
{
rangeB = rangesToMergeSorted[i];
if (rangeB.Minimum > rangeA.Maximum)
{
mergedRanges.Add(rangeA.Copy());
rangeA = rangeB.Copy();
addB = true;
addA = false;
}
else
{
if (rangeB.Maximum > rangeA.Maximum)
{
rangeA.Maximum = rangeB.Maximum;
}
addA = true;
addB = false;
}
}
if (addA)
{
mergedRanges.Add(rangeA);
}
if (addB)
{
mergedRanges.Add(rangeB);
}
return(new IPRanges(mergedRanges));
}
public IPRanges(IPRange range)
{
Ranges.Add(range);
}