OpenTween.Twitter.ParseSource C# (CSharp) Method

        public static Tuple<string, Uri> ParseSource(string sourceHtml)
        {
            if (string.IsNullOrEmpty(sourceHtml))
                return Tuple.Create<string, Uri>("", null);

            string sourceText;
            Uri sourceUri;

            // sourceHtmlの例: <a href="http://twitter.com" rel="nofollow">Twitter Web Client</a>

            var match = Regex.Match(sourceHtml, "^<a href=\"(?<uri>.+?)\".*?>(?<text>.+)</a>$", RegexOptions.IgnoreCase);
            if (match.Success)
            {
                sourceText = WebUtility.HtmlDecode(match.Groups["text"].Value);
                try
                {
                    var uriStr = WebUtility.HtmlDecode(match.Groups["uri"].Value);
                    sourceUri = new Uri(SourceUriBase, uriStr);
                }
                catch (UriFormatException)
                {
                    sourceUri = null;
                }
            }
            else
            {
                sourceText = WebUtility.HtmlDecode(sourceHtml);
                sourceUri = null;
            }

            return Tuple.Create(sourceText, sourceUri);
        }