public DiffResult CreateCustomDiffs(string oldText, string newText, bool ignoreWhiteSpace, bool ignoreCase, Func<string, string[]> chunker)
{
if (oldText == null) throw new ArgumentNullException("oldText");
if (newText == null) throw new ArgumentNullException("newText");
if (chunker == null) throw new ArgumentNullException("chunker");
var pieceHash = new Dictionary<string, int>();
var lineDiffs = new List<DiffBlock>();
var modOld = new ModificationData(oldText);
var modNew = new ModificationData(newText);
BuildPieceHashes(pieceHash, modOld, ignoreWhiteSpace, ignoreCase, chunker);
BuildPieceHashes(pieceHash, modNew, ignoreWhiteSpace, ignoreCase, chunker);
BuildModificationData(modOld, modNew);
int piecesALength = modOld.HashedPieces.Length;
int piecesBLength = modNew.HashedPieces.Length;
int posA = 0;
int posB = 0;
do
{
while (posA < piecesALength
&& posB < piecesBLength
&& !modOld.Modifications[posA]
&& !modNew.Modifications[posB])
{
posA++;
posB++;
}
int beginA = posA;
int beginB = posB;
for (; posA < piecesALength && modOld.Modifications[posA]; posA++) ;
for (; posB < piecesBLength && modNew.Modifications[posB]; posB++) ;
int deleteCount = posA - beginA;
int insertCount = posB - beginB;
if (deleteCount > 0 || insertCount > 0)
{
lineDiffs.Add(new DiffBlock(beginA, deleteCount, beginB, insertCount));
}
} while (posA < piecesALength && posB < piecesBLength);
return new DiffResult(modOld.Pieces, modNew.Pieces, lineDiffs);
}
private static void BuildModificationData
(ModificationData A,
int startA,
int endA,
ModificationData B,
int startB,
int endB,
int[] forwardDiagonal,
int[] reverseDiagonal)
{
while (startA < endA && startB < endB && A.HashedPieces[startA].Equals(B.HashedPieces[startB]))
{
startA++;
startB++;
}
while (startA < endA && startB < endB && A.HashedPieces[endA - 1].Equals(B.HashedPieces[endB - 1]))
{
endA--;
endB--;
}
int aLength = endA - startA;
int bLength = endB - startB;
if (aLength > 0 && bLength > 0)
{
EditLengthResult res = CalculateEditLength(A.HashedPieces, startA, endA, B.HashedPieces, startB, endB, forwardDiagonal, reverseDiagonal);
if (res.EditLength <= 0) return;
if (res.LastEdit == Edit.DeleteRight && res.StartX - 1 > startA)
A.Modifications[--res.StartX] = true;
else if (res.LastEdit == Edit.InsertDown && res.StartY - 1 > startB)
B.Modifications[--res.StartY] = true;
else if (res.LastEdit == Edit.DeleteLeft && res.EndX < endA)
A.Modifications[res.EndX++] = true;
else if (res.LastEdit == Edit.InsertUp && res.EndY < endB)
B.Modifications[res.EndY++] = true;
BuildModificationData(A, startA, res.StartX, B, startB, res.StartY, forwardDiagonal, reverseDiagonal);
BuildModificationData(A, res.EndX, endA, B, res.EndY, endB, forwardDiagonal, reverseDiagonal);
}
else if (aLength > 0)
{
for (int i = startA; i < endA; i++)
A.Modifications[i] = true;
}
else if (bLength > 0)
{
for (int i = startB; i < endB; i++)
B.Modifications[i] = true;
}
}
private static void BuildPieceHashes(IDictionary<string, int> pieceHash, ModificationData data, bool ignoreWhitespace, bool ignoreCase, Func<string, string[]> chunker)
{
string[] pieces;
if (string.IsNullOrEmpty(data.RawData))
pieces = new string[0];
else
pieces = chunker(data.RawData);
data.Pieces = pieces;
data.HashedPieces = new int[pieces.Length];
data.Modifications = new bool[pieces.Length];
for (int i = 0; i < pieces.Length; i++)
{
string piece = pieces[i];
if (ignoreWhitespace) piece = piece.Trim();
if (ignoreCase) piece = piece.ToUpperInvariant();
if (pieceHash.ContainsKey(piece))
{
data.HashedPieces[i] = pieceHash[piece];
}
else
{
data.HashedPieces[i] = pieceHash.Count;
pieceHash[piece] = pieceHash.Count;
}
}
}
protected static void BuildModificationData(ModificationData A, ModificationData B)
{
int N = A.HashedPieces.Length;
int M = B.HashedPieces.Length;
int MAX = M + N + 1;
var forwardDiagonal = new int[MAX + 1];
var reverseDiagonal = new int[MAX + 1];
BuildModificationData(A, 0, N, B, 0, M, forwardDiagonal, reverseDiagonal);
}
