System.UriTemplate.ParsePathTemplate C# (CSharp) Method

		ReadOnlyCollection<string> ParsePathTemplate (string template, int index, int end)
		{
			int widx = template.IndexOf ('*', index, end);
			if (widx >= 0 && widx != end - 1)
				throw new FormatException (String.Format ("Wildcard in UriTemplate is valid only if it is placed at the last part of the path: '{0}'", template));
			List<string> list = null;
			int prevEnd = -2;
			for (int i = index; i <= end; ) {
				i = template.IndexOf ('{', i);
				if (i < 0 || i > end)
					break;
				if (i == prevEnd + 1)
					throw new ArgumentException (String.Format ("The UriTemplate '{0}' contains adjacent templated segments, which is invalid.", template));
				int e = template.IndexOf ('}', i + 1);
				if (e < 0 || i > end)
					throw new FormatException (String.Format ("Missing '}' in URI template '{0}'", template));
				prevEnd = e;
				if (list == null)
					list = new List<string> ();
				i++;
				string name = template.Substring (i, e - i);
				string uname = name.ToUpper (CultureInfo.InvariantCulture);
				if (list.Contains (uname) || (path != null && path.Contains (uname)))
					throw new InvalidOperationException (String.Format ("The URI template string contains duplicate template item {{'{0}'}}", name));
				list.Add (uname);
				i = e + 1;
			}
			return list != null ? new ReadOnlyCollection<string> (list) : empty_strings;
		}