/// <summary>
/// Compares the text.
/// </summary>
/// <param name="oldText">The old text.</param>
/// <param name="newText">The new text.</param>
/// <param name="displayInsertedText">if set to <c>true</c> [display inserted text].</param>
/// <param name="displayDeletedText">if set to <c>true</c> [display deleted text].</param>
/// <param name="insertedStyle">The inserted style.</param>
/// <param name="deletedStyle">The deleted style.</param>
/// <returns></returns>
private static string CompareText(string oldText, string newText, bool displayInsertedText,
bool displayDeletedText, string insertedStyle, string deletedStyle)
{
var sb = new StringBuilder();
var diffs = Diff.DiffText1(oldText, newText);
int pos = 0;
for (int n = 0; n < diffs.Length; n++)
{
Diff.Item it = diffs[n];
// write unchanged chars
while ((pos < it.StartB) && (pos < newText.Length))
{
sb.Append(newText[pos]);
pos++;
} // while
// write deleted chars
if (displayDeletedText && it.DeletedA > 0)
{
sb.Append(deletedStyle);
for (int m = 0; m < it.DeletedA; m++)
{
sb.Append(oldText[it.StartA + m]);
} // for
sb.Append("</span>");
}
// write inserted chars
if (displayInsertedText && pos < it.StartB + it.InsertedB)
{
sb.Append(insertedStyle);
while (pos < it.StartB + it.InsertedB)
{
sb.Append(newText[pos]);
pos++;
} // while
sb.Append("</span>");
} // if
} // while
// write rest of unchanged chars
while (pos < newText.Length)
{
sb.Append(newText[pos]);
pos++;
} // while
return(sb.ToString());
}
