public virtual Differences VisitBlockList(BlockList list1, BlockList list2,
out BlockList changes, out BlockList deletions, out BlockList insertions){
changes = list1 == null ? null : list1.Clone();
deletions = list1 == null ? null : list1.Clone();
insertions = list1 == null ? new BlockList() : list1.Clone();
//^ assert insertions != null;
Differences differences = new Differences();
for (int j = 0, n = list2 == null ? 0 : list2.Count; j < n; j++){
//^ assert list2 != null;
Block nd2 = list2[j];
if (nd2 == null) continue;
insertions.Add(null);
}
TrivialHashtable savedDifferencesMapFor = this.differencesMapFor;
this.differencesMapFor = null;
TrivialHashtable matchedNodes = new TrivialHashtable();
for (int i = 0, k = 0, n = list1 == null ? 0 : list1.Count; i < n; i++){
//^ assert list1 != null && changes != null && deletions != null;
Block nd1 = list1[i];
if (nd1 == null) continue;
Differences diff;
int j;
Block nd2 = this.GetClosestMatch(nd1, list1, list2, i, ref k, matchedNodes, out diff, out j);
if (nd2 == null || diff == null){Debug.Assert(nd2 == null && diff == null); continue;}
matchedNodes[nd1.UniqueKey] = nd1;
matchedNodes[nd2.UniqueKey] = nd2;
changes[i] = diff.Changes as Block;
deletions[i] = diff.Deletions as Block;
insertions[i] = diff.Insertions as Block;
insertions[n+j] = nd1; //Records the position of nd2 in list2 in case the change involved a permutation
Debug.Assert(diff.Changes == changes[i] && diff.Deletions == deletions[i] && diff.Insertions == insertions[i]);
differences.NumberOfDifferences += diff.NumberOfDifferences;
differences.NumberOfSimilarities += diff.NumberOfSimilarities;
}
//Find deletions
for (int i = 0, n = list1 == null ? 0 : list1.Count; i < n; i++){
//^ assert list1 != null && changes != null && deletions != null;
Block nd1 = list1[i];
if (nd1 == null) continue;
if (matchedNodes[nd1.UniqueKey] != null) continue;
changes[i] = null;
deletions[i] = nd1;
insertions[i] = null;
differences.NumberOfDifferences += 1;
}
//Find insertions
for (int j = 0, n = list1 == null ? 0 : list1.Count, m = list2 == null ? 0 : list2.Count; j < m; j++){
//^ assert list2 != null;
Block nd2 = list2[j];
if (nd2 == null) continue;
if (matchedNodes[nd2.UniqueKey] != null) continue;
insertions[n+j] = nd2; //Records nd2 as an insertion into list1, along with its position in list2
differences.NumberOfDifferences += 1; //REVIEW: put the size of the tree here?
}
if (differences.NumberOfDifferences == 0){
changes = null;
deletions = null;
insertions = null;
}
this.differencesMapFor = savedDifferencesMapFor;
return differences;
}