public ArrayList DiffResult()
{
ArrayList retval = new ArrayList();
int dcount = destList.Count();
int scount = sourceList.Count();
//Deal with the special case of empty files
if (dcount == 0)
{
if (scount > 0)
{
retval.Add(CompareResultSpan.CreateDeleteSource(0, scount));
}
return(retval);
}
if (scount == 0)
{
retval.Add(CompareResultSpan.CreateAddDestination(0, dcount));
return(retval);
}
matchList.Sort();
int curDest = 0;
int curSource = 0;
CompareResultSpan last = null;
//Process each match record
foreach (CompareResultSpan drs in matchList)
{
if ((!AddChanges(retval, curDest, drs.DestinationIndex, curSource, drs.SourceIndex)) &&
(last != null))
{
last.AddLength(drs.Length);
}
else
{
retval.Add(drs);
}
curDest = drs.DestinationIndex + drs.Length;
curSource = drs.SourceIndex + drs.Length;
last = drs;
}
//Process any tail end data
AddChanges(retval, curDest, dcount, curSource, scount);
return(retval);
}
private static bool AddChanges(
IList report,
int curDest,
int nextDest,
int curSource,
int nextSource)
{
bool retval = false;
int diffDest = nextDest - curDest;
int diffSource = nextSource - curSource;
if (diffDest > 0)
{
if (diffSource > 0)
{
int minDiff = Math.Min(diffDest, diffSource);
report.Add(CompareResultSpan.CreateReplace(curDest, curSource, minDiff));
if (diffDest > diffSource)
{
curDest += minDiff;
report.Add(CompareResultSpan.CreateAddDestination(curDest, diffDest - diffSource));
}
else
{
if (diffSource > diffDest)
{
curSource += minDiff;
report.Add(CompareResultSpan.CreateDeleteSource(curSource, diffSource - diffDest));
}
}
}
else
{
report.Add(CompareResultSpan.CreateAddDestination(curDest, diffDest));
}
retval = true;
}
else
{
if (diffSource > 0)
{
report.Add(CompareResultSpan.CreateDeleteSource(curSource, diffSource));
retval = true;
}
}
return(retval);
}
//This is the actual recursive search that looks for longes common-subsequence
private void RecursiveComparer(int destinationStart, int destinationEnd, int sourceStart, int sourceEnd)
{
int curBestIndex = -1;
int curBestLength = -1;
CompareState currentItem;
CompareState bestItem = null;
for (int count = destinationStart; count <= destinationEnd; count++)
{
int maxPossibleDestLength = (destinationEnd - count) + 1;
if (maxPossibleDestLength <= curBestLength)
{
//not enough text remaining to be larger then the current best
break;
}
currentItem = compareStateList.GetByIndex(count);
if (!currentItem.HasValidLength(sourceStart, sourceEnd, maxPossibleDestLength))
{
//recalc new best length since it isn't valid or has never been done.
GetLongestSourceMatch(currentItem, count, destinationEnd, sourceStart, sourceEnd);
}
if (currentItem.Status == CompareStatus.Matched)
{
if (currentItem.Length > curBestLength)
{
//this is longest match so far
curBestIndex = count;
curBestLength = currentItem.Length;
bestItem = currentItem;
}
break;
}
}
if (curBestIndex < 0)
{
//we are done - there are no matches in this span
}
else
{
int sourceIndex = 0;
if (bestItem != null)
{
sourceIndex = bestItem.StartIndex;
}
matchList.Add(CompareResultSpan.CreateNoChange(curBestIndex, sourceIndex, curBestLength));
if (destinationStart < curBestIndex)
{
//Still have more lower destination data
if (sourceStart < sourceIndex)
{
//Still have more lower source data
// Recursive call to process lower indexes
RecursiveComparer(destinationStart, curBestIndex - 1, sourceStart, sourceIndex - 1);
}
}
int upperDestStart = curBestIndex + curBestLength;
int upperSourceStart = sourceIndex + curBestLength;
if (destinationEnd > upperDestStart)
{
//we still have more upper dest data
if (sourceEnd > upperSourceStart)
{
//set still have more upper source data
// Recursive call to process upper indexes
RecursiveComparer(upperDestStart, destinationEnd, upperSourceStart, sourceEnd);
}
}
}
}
