public AlignmentNode(DiffOperation operation, double similarity, int nodeCount, [CanBeNull] AlignmentNode next)
{
Operation = operation;
Similarity = similarity;
NodeCount = nodeCount;
Next = next;
}
private AlignmentNode CalculateBestAlignment([NotNull] Dictionary <AlignmentKey, AlignmentNode> nodes, [NotNull] IList <T> collection1, int lower1, int upper1, [NotNull] IList <T> collection2, int lower2, int upper2)
{
var key = new AlignmentKey(lower1, lower2);
AlignmentNode result;
if (nodes.TryGetValue(key, out result))
{
Assume.That(result != null);
return(result);
}
if (lower1 == upper1 && lower2 == upper2)
{
result = new AlignmentNode(DiffOperation.Match, 0.0, 0, null);
}
else if (lower1 == upper1)
{
var restAfterInsert = CalculateBestAlignment(nodes, collection1, lower1, upper1, collection2, lower2 + 1, upper2);
result = new AlignmentNode(DiffOperation.Insert, restAfterInsert.Similarity, restAfterInsert.NodeCount + 1, restAfterInsert);
}
else if (lower2 == upper2)
{
var restAfterDelete = CalculateBestAlignment(nodes, collection1, lower1 + 1, upper1, collection2, lower2, upper2);
result = new AlignmentNode(DiffOperation.Delete, restAfterDelete.Similarity, restAfterDelete.NodeCount + 1, restAfterDelete);
}
else
{
// Calculate how the results will be if we insert a new element
var restAfterInsert = CalculateBestAlignment(nodes, collection1, lower1, upper1, collection2, lower2 + 1, upper2);
var resultInsert = new AlignmentNode(DiffOperation.Insert, restAfterInsert.Similarity, restAfterInsert.NodeCount + 1, restAfterInsert);
// Calculate how the results will be if we delete an element
var restAfterDelete = CalculateBestAlignment(nodes, collection1, lower1 + 1, upper1, collection2, lower2, upper2);
var resultDelete = new AlignmentNode(DiffOperation.Delete, restAfterDelete.Similarity, restAfterDelete.NodeCount + 1, restAfterDelete);
// Calculate how the results will be if we replace or modify an element
var restAfterChange = CalculateBestAlignment(nodes, collection1, lower1 + 1, upper1, collection2, lower2 + 1, upper2);
double similarity = _SimilarityFunc(collection1[lower1], collection2[lower2]);
AlignmentNode resultChange = null;
if (similarity >= _ModificationThreshold)
{
resultChange = new AlignmentNode(DiffOperation.Modify, similarity + restAfterInsert.Similarity, restAfterChange.NodeCount + 1, restAfterChange);
}
// Then pick the operation that resulted in the best average similarity
result = resultDelete;
if (resultInsert.AverageSimilarity > result.AverageSimilarity)
{
result = resultInsert;
}
if (resultChange?.AverageSimilarity > result.AverageSimilarity)
{
result = resultChange;
}
}
nodes[key] = result;
return(result);
}
