public List <DiffResultSpan> DiffReport()
{
var retval = new List <DiffResultSpan>();
var dcount = _dest.Count();
var scount = _source.Count();
//Deal with the special case of empty files
if (dcount == 0)
{
if (scount > 0)
{
retval.Add(DiffResultSpan.CreateDeleteSource(0, scount));
}
return(retval);
}
else
{
if (scount == 0)
{
retval.Add(DiffResultSpan.CreateAddDestination(0, dcount));
return(retval);
}
}
_matchList.Sort();
var curDest = 0;
var curSource = 0;
DiffResultSpan last = null;
//Process each match record
foreach (var 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(
List <DiffResultSpan> report,
int curDest,
int nextDest,
int curSource,
int nextSource)
{
var retval = false;
var diffDest = nextDest - curDest;
var diffSource = nextSource - curSource;
var minDiff = 0;
if (diffDest > 0)
{
if (diffSource > 0)
{
minDiff = Math.Min(diffDest, diffSource);
report.Add(DiffResultSpan.CreateReplace(curDest, curSource, minDiff));
if (diffDest > diffSource)
{
curDest += minDiff;
report.Add(DiffResultSpan.CreateAddDestination(curDest, diffDest - diffSource));
}
else
{
if (diffSource > diffDest)
{
curSource += minDiff;
report.Add(DiffResultSpan.CreateDeleteSource(curSource, diffSource - diffDest));
}
}
}
else
{
report.Add(DiffResultSpan.CreateAddDestination(curDest, diffDest));
}
retval = true;
}
else
{
if (diffSource > 0)
{
report.Add(DiffResultSpan.CreateDeleteSource(curSource, diffSource));
retval = true;
}
}
return(retval);
}
private void ProcessRange(int destStart, int destEnd, int sourceStart, int sourceEnd)
{
var curBestIndex = -1;
var curBestLength = -1;
var maxPossibleDestLength = 0;
DiffState curItem = null;
DiffState bestItem = null;
for (var 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
{
var 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);
}
}
var upperDestStart = curBestIndex + curBestLength;
var 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);
}
}
}
}