DotNetOpenAuth.OpenId.Realm.Contains C# (CSharp) Method

		internal bool Contains(Uri url) {
			if (url.Scheme != this.Scheme) {
				return false;
			}

			if (url.Port != this.Port) {
				return false;
			}

			if (!this.DomainWildcard) {
				if (url.Host != this.Host) {
					return false;
				}
			} else {
				Debug.Assert(!string.IsNullOrEmpty(this.Host), "The host part of the Regex should evaluate to at least one char for successful parsed trust roots.");
				string[] host_parts = this.Host.Split('.');
				string[] url_parts = url.Host.Split('.');

				// If the domain containing the wildcard has more parts than the URL to match against,
				// it naturally can't be valid.
				// Unless *.example.com actually matches example.com too.
				if (host_parts.Length > url_parts.Length) {
					return false;
				}

				// Compare last part first and move forward.
				// Maybe could be done by using EndsWith, but piecewies helps ensure that
				// *.my.com doesn't match ohmeohmy.com but can still match my.com.
				for (int i = 0; i < host_parts.Length; i++) {
					string hostPart = host_parts[host_parts.Length - 1 - i];
					string urlPart = url_parts[url_parts.Length - 1 - i];
					if (!string.Equals(hostPart, urlPart, StringComparison.OrdinalIgnoreCase)) {
						return false;
					}
				}
			}

			// If path matches or is specified to root ... 
			// (deliberately case sensitive to protect security on case sensitive systems)
			if (this.PathAndQuery.Equals(url.PathAndQuery, StringComparison.Ordinal)
				|| this.PathAndQuery.Equals("/", StringComparison.Ordinal)) {
				return true;
			}

			// If trust root has a longer path, the return URL must be invalid.
			if (this.PathAndQuery.Length > url.PathAndQuery.Length) {
				return false;
			}

			// The following code assures that http://example.com/directory isn't below http://example.com/dir,
			// but makes sure http://example.com/dir/ectory is below http://example.com/dir
			int path_len = this.PathAndQuery.Length;
			string url_prefix = url.PathAndQuery.Substring(0, path_len);

			if (this.PathAndQuery != url_prefix) {
				return false;
			}

			// If trust root includes a query string ...
			if (this.PathAndQuery.Contains("?")) {
				// ... make sure return URL begins with a new argument
				return url.PathAndQuery[path_len] == '&';
			}

			// Or make sure a query string is introduced or a path below trust root
			return this.PathAndQuery.EndsWith("/", StringComparison.Ordinal)
				|| url.PathAndQuery[path_len] == '?'
				|| url.PathAndQuery[path_len] == '/';
		}