public ArrayList DifferenceReport()
{
ArrayList retval = new ArrayList();
int dcount = _destination.Count();
int scount = _source.Count();
// Deal with the special case of empty files
if (dcount == 0)
{
if (scount > 0)
{
retval.Add(DifferenceResultSpan.CreateDeleteSource(0, scount));
}
return(retval);
}
else
{
if (scount == 0)
{
retval.Add(DifferenceResultSpan.CreateAddDestination(0, dcount));
return(retval);
}
}
_matchList.Sort();
int curDest = 0;
int curSource = 0;
DifferenceResultSpan last = null;
// Process each match record
foreach (DifferenceResultSpan drs in _matchList)
{
if ((!AddChanges(retval, curDest, drs.DestIndex, curSource, drs.SourceIndex)) &&
(last != null))
{
last.AddLength(drs.Length);
}
else
{
retval.Add(drs);
}
curDest = drs.DestIndex + drs.Length;
curSource = drs.SourceIndex + drs.Length;
last = drs;
}
// Process any tail end data
AddChanges(retval, curDest, dcount, curSource, scount);
return(retval);
}
private bool AddChanges(ArrayList 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(DifferenceResultSpan.CreateReplace(curDest, curSource, minDiff));
if (diffDest > diffSource)
{
curDest += minDiff;
report.Add(DifferenceResultSpan.CreateAddDestination(curDest, diffDest - diffSource));
}
else
{
if (diffSource > diffDest)
{
curSource += minDiff;
report.Add(DifferenceResultSpan.CreateDeleteSource(curSource, diffSource - diffDest));
}
}
}
else
{
report.Add(DifferenceResultSpan.CreateAddDestination(curDest, diffDest));
}
retval = true;
}
else
{
if (diffSource > 0)
{
report.Add(DifferenceResultSpan.CreateDeleteSource(curSource, diffSource));
retval = true;
}
}
return(retval);
}
private void ProcessRange(int destStart, int destEnd, int sourceStart, int sourceEnd)
{
int curBestIndex = -1;
int curBestLength = -1;
DifferenceState curItem;
DifferenceState bestItem = null;
for (int destIndex = destStart; destIndex <= destEnd; destIndex++)
{
int 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 == DifferenceStatus.Matched)
{
switch (_level)
{
case DifferenceEngineLevel.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 DifferenceEngineLevel.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
{
if (bestItem != null)
{
int sourceIndex = bestItem.StartIndex;
_matchList.Add(DifferenceResultSpan.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);
}
}
}
}
}