private void GetLongestSourceMatch(CompareState curItem, int destIndex, int destEnd, int sourceStart,
int sourceEnd)
{
int maxDestLength = (destEnd - destIndex) + 1;
int curBestLength = 0;
int curBestIndex = -1;
for (int sourceIndex = sourceStart; sourceIndex <= sourceEnd; sourceIndex++)
{
int maxLength = Math.Min(maxDestLength, (sourceEnd - sourceIndex) + 1);
if (maxLength <= curBestLength)
{
//No chance to find a longer one any more
break;
}
int curLength = GetSourceMatchLength(destIndex, sourceIndex, maxLength);
if (curLength > curBestLength)
{
//This is the best match so far
curBestIndex = sourceIndex;
curBestLength = curLength;
}
//jump over the match
sourceIndex += curBestLength;
}
//DiffState cur = _stateList.GetByIndex(destIndex);
if (curBestIndex == -1)
{
curItem.SetNoMatch();
}
else
{
curItem.SetMatch(curBestIndex, curBestLength);
}
}
//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);
}
}
}
}
