/// <summary>
/// Retrieves the text for a portion of the rope.
/// Runs in O(lg N + M), where M=<paramref name="length"/>.
/// </summary>
/// <exception cref="ArgumentOutOfRangeException">offset or length is outside the valid range.</exception>
/// <remarks>
/// This method counts as a read access and may be called concurrently to other read accesses.
/// </remarks>
public static string ToString(this Rope <char> rope, int startIndex, int length)
{
if (rope == null)
{
throw new ArgumentNullException(nameof(rope));
}
#if DEBUG
if (length < 0)
{
throw new ArgumentOutOfRangeException(nameof(length), length, "Value must be >= 0");
}
#endif
if (length == 0)
{
return(string.Empty);
}
char[] buffer = new char[length];
rope.CopyTo(startIndex, buffer, 0, length);
return(new string(buffer));
}