System.Uri.PathDifference C# (CSharp) Method

        private static string PathDifference(string path1, string path2, bool compareCase)
        {
            int i;
            int si = -1;

            for (i = 0; (i < path1.Length) && (i < path2.Length); ++i)
            {
                if ((path1[i] != path2[i])
                    && (compareCase
                        || (char.ToLowerInvariant(path1[i])
                            != char.ToLowerInvariant(path2[i]))))
                {
                    break;
                }
                else if (path1[i] == '/')
                {
                    si = i;
                }
            }

            if (i == 0)
            {
                return path2;
            }
            if ((i == path1.Length) && (i == path2.Length))
            {
                return string.Empty;
            }

            StringBuilder relPath = new StringBuilder();
            // Walk down several dirs
            for (; i < path1.Length; ++i)
            {
                if (path1[i] == '/')
                {
                    relPath.Append("../");
                }
            }
            // Same path except that path1 ended with a file name and path2 didn't
            if (relPath.Length == 0 && path2.Length - 1 == si)
                return "./"; // Truncate the file name
            return relPath.ToString() + path2.Substring(si + 1);
        }