static void BuildModificationData(ModificationData a, ModificationData b)
{
var n = a.HashedPieces.Length;
var m = b.HashedPieces.Length;
var 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);
}
public static DiffResult CreateVbaDiffs(string oldText, string newText)
{
if (oldText == null)
{
throw new ArgumentNullException(nameof(oldText));
}
if (newText == null)
{
throw new ArgumentNullException(nameof(newText));
}
var pieceHash = new Dictionary <string, int>();
var lineDiffs = new List <DiffBlock>();
var modOld = new ModificationData(oldText);
var modNew = new ModificationData(newText);
BuildPieceHashes(pieceHash, modOld);
BuildPieceHashes(pieceHash, modNew);
BuildModificationData(modOld, modNew);
var piecesALength = modOld.HashedPieces.Length;
var piecesBLength = modNew.HashedPieces.Length;
var posA = 0;
var posB = 0;
do
{
while (posA < piecesALength &&
posB < piecesBLength &&
!modOld.Modifications[posA] &&
!modNew.Modifications[posB])
{
posA++;
posB++;
}
var beginA = posA;
var beginB = posB;
while (posA < piecesALength && modOld.Modifications[posA])
{
posA++;
}
while (posB < piecesBLength && modNew.Modifications[posB])
{
posB++;
}
var deleteCount = posA - beginA;
var 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 (var i = startA; i < endA; i++)
{
a.Modifications[i] = true;
}
}
else if (bLength > 0)
{
for (var i = startB; i < endB; i++)
{
b.Modifications[i] = true;
}
}
}
