/// <summary>
/// Extract a substring.
/// </summary>
/// <param name="startIndex">Index to start from.</param>
/// <param name="length">Count of characters to extract.</param>
/// <returns>The substring.</returns>
public IString Substring(int startIndex, int length)
{
var currentIndex = 0;
var lengthLeft = length;
var builder = new ColoredMultistringBuilder();
foreach (var piece in Content)
{
if (currentIndex + piece.Length <= startIndex)
{
// Do nothing.
}
else
{
var offsetIntoPiece = (startIndex <= currentIndex) ? 0 : startIndex - currentIndex;
var charsToCopy = Math.Min(lengthLeft, piece.Length - offsetIntoPiece);
Debug.Assert(charsToCopy > 0);
if (charsToCopy == piece.Length)
{
builder.Append(piece);
}
else
{
builder.Append(piece.Substring(offsetIntoPiece, charsToCopy));
}
lengthLeft -= charsToCopy;
Debug.Assert(lengthLeft >= 0);
if (lengthLeft == 0)
{
break;
}
}
currentIndex += piece.Length;
}
if (lengthLeft > 0)
{
throw new IndexOutOfRangeException($"Invalid substring extraction");
}
return(builder.ToMultistring());
}
/// <summary>
/// Split the string by the indicated separator.
/// </summary>
/// <param name="separator">Separator for splitting.</param>
/// <param name="options">Split options.</param>
/// <returns>The split pieces of the string.</returns>
public IEnumerable <IString> Split(char separator, StringSplitOptions options = StringSplitOptions.None)
{
ColoredMultistringBuilder builder = null;
foreach (var piece in Content)
{
var s = piece.Content;
int index;
while ((index = s.IndexOf(separator)) >= 0)
{
if (index > 0 || (index == 0 && options == StringSplitOptions.None))
{
if (builder == null)
{
builder = new ColoredMultistringBuilder();
}
var firstPart = s.Substring(0, index);
builder.Append(piece.WithContent(firstPart));
yield return(builder.ToMultistring());
builder = null;
}
s = s.Substring(index + 1);
}
if (!string.IsNullOrEmpty(s))
{
if (builder == null)
{
builder = new ColoredMultistringBuilder();
}
builder.Append(piece.WithContent(s));
}
}
if (builder != null)
{
yield return(builder.ToMultistring());
}
}