private void ProcessRange(int destStart, int destEnd, int sourceStart, int sourceEnd)
{
int curBestIndex = -1;
int curBestLength = -1;
int maxPossibleDestLength = 0;
DiffState curItem = null;
DiffState bestItem = null;
for (int destIndex = destStart; destIndex <= destEnd; destIndex++)
{
maxPossibleDestLength = (destEnd - destIndex) + 1;
if (maxPossibleDestLength <= curBestLength)
{
//we won't find a longer one even if we looked
break;
}
curItem = _stateList.GetByIndex(destIndex);
if (!curItem.HasValidLength(sourceStart, sourceEnd, maxPossibleDestLength))
{
//recalc new best length since it isn't valid or has never been done.
GetLongestSourceMatch(curItem, destIndex, destEnd, sourceStart, sourceEnd);
}
if (curItem.Status == DiffStatus.Matched)
{
switch (_level)
{
case DiffEngineLevel.FastImperfect:
if (curItem.Length > curBestLength)
{
//this is longest match so far
curBestIndex = destIndex;
curBestLength = curItem.Length;
bestItem = curItem;
}
//Jump over the match
destIndex += curItem.Length - 1;
break;
case DiffEngineLevel.Medium:
if (curItem.Length > curBestLength)
{
//this is longest match so far
curBestIndex = destIndex;
curBestLength = curItem.Length;
bestItem = curItem;
//Jump over the match
destIndex += curItem.Length - 1;
}
break;
default:
if (curItem.Length > curBestLength)
{
//this is longest match so far
curBestIndex = destIndex;
curBestLength = curItem.Length;
bestItem = curItem;
}
break;
}
}
}
if (curBestIndex < 0)
{
//we are done - there are no matches in this span
}
else
{
int sourceIndex = bestItem.StartIndex;
_matchList.Add(DiffResultSpan.CreateNoChange(curBestIndex, sourceIndex, curBestLength));
if (destStart < curBestIndex)
{
//Still have more lower destination data
if (sourceStart < sourceIndex)
{
//Still have more lower source data
// Recursive call to process lower indexes
ProcessRange(destStart, curBestIndex - 1, sourceStart, sourceIndex - 1);
}
}
int upperDestStart = curBestIndex + curBestLength;
int upperSourceStart = sourceIndex + curBestLength;
if (destEnd > upperDestStart)
{
//we still have more upper dest data
if (sourceEnd > upperSourceStart)
{
//set still have more upper source data
// Recursive call to process upper indexes
ProcessRange(upperDestStart, destEnd, upperSourceStart, sourceEnd);
}
}
}
}