Added an email address validity checker.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5387 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/as/com/threerings/util/MailUtil.as

@@ -0,0 +1,46 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2008 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.util {
+
+/**
+ * Utility methods relating to the electronic mails.
+ */
+public class MailUtil
+{
+    /**
+     * Returns true if the supplied email address appears valid (according to a widely used regular
+     * expression). False if it does not.
+     */
+    public static function isValidAddress (email :String) :Boolean
+    {
+        var matches :Array = email.match(EMAIL_REGEX);
+        // in theory there should only be one match and we should check for 'matches.length == 1',
+        // but Flash's regular expression code likes to return nonsensical things, so we just check
+        // that the first match is equal to the entire supplied address
+        return (matches != null && matches.length > 0) && ((matches[0] as String) == email);
+    }
+
+    /** Originally formulated by lambert@nas.nasa.gov. */
+    protected static const EMAIL_REGEX :RegExp = new RegExp(
+        "^([-a-z0-9_.!%+]+@[-a-z0-9]+(\\.[-a-z0-9]+)*\\.[-a-z0-9]+)$", "i");
+}
+}