private Change ProcessCommand(string command)
{
Change change = new Change();
int commandIndex = -1;
for (int i = 0; i < command.Length; i++) {
if (char.IsLetter(command[i])) {
commandIndex = i;
}
}
if (commandIndex == -1 || command.Length <= commandIndex) throw new Exception(invalidOutputMessage);
switch (command[commandIndex]) {
case 'd': change.Type = ChangeType.Remove; break;
case 'c': change.Type = ChangeType.Change; break;
case 'a': change.Type = ChangeType.Add; break;
default: throw new Exception(invalidOutputMessage);
}
string left = command.Substring(0, commandIndex);
string right = command.Substring(commandIndex + 1);
ProcessRange(left, out change.StartPosition1, out change.EndPosition1);
ProcessRange(right, out change.StartPosition2, out change.EndPosition2);
return change;
}
private void Diff(DiffDocument r, DiffDocument c, int i, int j)
{
if (i > 0 && j > 0 && r[i] == c[j]) {
Diff(r, c, i - 1, j - 1);
} else {
if (j > 0 && (i == 0 || table[i][j - 1] >= table[i - 1][j])) {
Diff(r, c, i, j - 1);
if (lastChange == null || lastChange.Type != ChangeType.Add) {
if (lastChange != null) {
changeList.Add(lastChange);
}
lastChange = new Change() { Type = ChangeType.Add, StartPosition1 = i, StartPosition2 = j };
}
lastChange.TextAdded += c[j] + Environment.NewLine;
} else if (i > 0 && (j == 0 || table[i][j - 1] < table[i - 1][j])) {
Diff(r, c, i - 1, j);
if (lastChange == null || lastChange.Type != ChangeType.Remove) {
if (lastChange != null) {
changeList.Add(lastChange);
}
lastChange = new Change() { Type = ChangeType.Remove, StartPosition1 = i, StartPosition2 = j };
}
lastChange.TextDeleted += r[i] + Environment.NewLine;
}
if (lastChange != null) {
lastChange.EndPosition1 = i;
lastChange.EndPosition2 = j;
}
}
}