update is_email to 2.10.1

1 files changed, 102 insertions, 62 deletions

diff --git a/is_email.php b/is_email.php
index 8af3247..3a29fbb 100644
--- a/is_email.php
+++ b/is_email.php
@@ -2,8 +2,8 @@
 /**

  * To validate an email address according to RFCs 5321, 5322 and others

  * 

- * Copyright (c) 2008-2010, Dominic Sayers							<br>

- * Test schema documentation Copyright (c) 2010, Daniel Marschall				<br>

+ * Copyright © 2008-2010, Dominic Sayers							<br>

+ * Test schema documentation Copyright © 2010, Daniel Marschall				<br>

  * All rights reserved.

  * 

  * Redistribution and use in source and binary forms, with or without modification,

@@ -34,18 +34,25 @@
  * @copyright	2008-2010 Dominic Sayers

  * @license	http://www.opensource.org/licenses/bsd-license.php BSD License

  * @link	http://www.dominicsayers.com/isemail

- * @version	2.4.2 - Workaround PHP bug (http://bugs.php.net/48645) in test script

+ * @version	2.10.1 - Amended DNS lookup logic. Also, in is_email_statustext.php, changed $type to integer to allow for additional types (starting with SMTP codes)

  */

 

 // The quality of this code has been improved greatly by using PHPLint

-// Copyright (c) 2009 Umberto Salsi

+// Copyright (c) 2010 Umberto Salsi

 // This is free software; see the license for copying conditions.

 // More info: http://www.icosaedro.it/phplint/

 /*.

 	require_module 'standard';

 	require_module 'pcre';

 .*/

-/*.mixed.*/ function is_email (/*.string.*/ $email, $checkDNS = false, $errorlevel = false) {

+/**

+ * Check that an email address conforms to RFCs 5321, 5322 and others

+ *

+ * @param string	$email		The email address to check

+ * @param boolean	$checkDNS	If true then a DNS check for A and MX records will be made

+ * @param mixed		$errorlevel	If true then return an integer error or warning number rather than true or false

+ */

+/*.mixed.*/ function is_email ($email, $checkDNS = false, $errorlevel = false) {

 	// Check that $email is a valid address. Read the following RFCs to understand the constraints:

 	// 	(http://tools.ietf.org/html/rfc5321)

 	// 	(http://tools.ietf.org/html/rfc5322)

@@ -61,10 +68,12 @@
 	//			addresses at TLDs (e.g. johndoe@com), addresses with FWS and comments,

 	//			addresses that are quoted and addresses that contain no alphabetic or

 	//			numeric characters.

+	//	true		Same as E_ERROR

 	//	false		Return true for valid addresses, false for invalid ones. No warnings.

 	//

 	//	Errors can be distinguished from warnings if ($return_value > ISEMAIL_ERROR)

 // version 2.0: Enhance $diagnose parameter to $errorlevel

+// revision 2.5: some syntax changes to make it more PHPLint-friendly. Should be functionally identical.

 

 	if (!defined('ISEMAIL_VALID')) {

 		// No errors

@@ -94,7 +103,7 @@
 		define('ISEMAIL_EMPTYELEMENT'		, 137);

 		define('ISEMAIL_UNESCAPEDSPECIAL'	, 138);

 		define('ISEMAIL_LOCALTOOLONG'		, 139);

-		define('ISEMAIL_IPV4BADPREFIX'		, 140);

+//		define('ISEMAIL_IPV4BADPREFIX'		, 140);

 		define('ISEMAIL_IPV6BADPREFIXMIXED'	, 141);

 		define('ISEMAIL_IPV6BADPREFIX'		, 142);

 		define('ISEMAIL_IPV6GROUPCOUNT'		, 143);

@@ -108,19 +117,37 @@
 		define('ISEMAIL_IPV6SINGLECOLONSTART'	, 151);

 		define('ISEMAIL_IPV6SINGLECOLONEND'	, 152);

 		// Unexpected errors

-		define('ISEMAIL_BADPARAMETER'		, 190);

-		define('ISEMAIL_NOTDEFINED'		, 191);

+//		define('ISEMAIL_BADPARAMETER'		, 190);

+//		define('ISEMAIL_NOTDEFINED'		, 191);

 // revision 2.1: Redefined unexpected error constants so they don't clash with the ISEMAIL_WARNING bit

+// revision 2.5: Undefined unused constants

 	}

 

-	switch ($errorlevel) {

-		case E_WARNING:	$diagnose = true;	$warn = true;	break;

-		case E_ERROR:	$diagnose = true;	$warn = false;	break;

-		case false:	$diagnose = false;	$warn = false;	break;

-		default:	$diagnose = false;	$warn = false;

+	if (is_bool($errorlevel)) {

+		if ((bool) $errorlevel) {

+			$diagnose	= true;

+			$warn		= false;

+		} else {

+			$diagnose	= false;

+			$warn		= false;

+		}

+	} else {

+		switch ((int) $errorlevel) {

+		case E_WARNING:

+			$diagnose	= true;

+			$warn		= true;

+			break;

+		case E_ERROR:

+			$diagnose	= true;

+			$warn		= false;

+			break;

+		default:

+			$diagnose	= false;

+			$warn		= false;

+		}

 	}

 

-	$return_status = ($diagnose) ? ISEMAIL_VALID : true;

+	if ($diagnose) /*.mixed.*/ $return_status = ISEMAIL_VALID; else $return_status = true;

 // version 2.0: Enhance $diagnose parameter to $errorlevel

 

 	// the upper limit on address lengths should normally be considered to be 254

@@ -133,16 +160,16 @@
 	//	NB There is a mandatory 2-character wrapper round the actual address

 	$emailLength = strlen($email);

 // revision 1.17: Max length reduced to 254 (see above)

-	if ($emailLength > 254)			return $diagnose ? ISEMAIL_TOOLONG	: false;	// Too long

+	if ($emailLength > 254)			if ($diagnose) return ISEMAIL_TOOLONG;		else return false;	// Too long

 

 	// Contemporary email addresses consist of a "local part" separated from

 	// a "domain part" (a fully-qualified domain name) by an at-sign ("@").

 	// 	(http://tools.ietf.org/html/rfc3696#section-3)

 	$atIndex = strrpos($email,'@');

 

-	if ($atIndex === false)			return $diagnose ? ISEMAIL_NOAT		: false;	// No at-sign

-	if ($atIndex === 0)			return $diagnose ? ISEMAIL_NOLOCALPART	: false;	// No local part

-	if ($atIndex === $emailLength - 1)	return $diagnose ? ISEMAIL_NODOMAIN	: false;	// No domain part

+	if ($atIndex === false)			if ($diagnose) return ISEMAIL_NOAT;		else return false;	// No at-sign

+	if ($atIndex === 0)			if ($diagnose) return ISEMAIL_NOLOCALPART;	else return false;	// No local part

+	if ($atIndex === $emailLength - 1)	if ($diagnose) return ISEMAIL_NODOMAIN;		else return false;	// No domain part

 // revision 1.14: Length test bug suggested by Andrew Campbell of Gloucester, MA

 

 	// Sanitize comments

@@ -198,6 +225,8 @@
 	$localPart	= substr($email, 0, $atIndex);

 	$domain		= substr($email, $atIndex + 1);

 	$FWS		= "(?:(?:(?:[ \\t]*(?:\\r\\n))?[ \\t]+)|(?:[ \\t]+(?:(?:\\r\\n)[ \\t]+)*))";	// Folding white space

+	$dotArray	= /*. (array[]) .*/ array();

+

 	// Let's check the local part for RFC compliance...

 	//

 	// local-part      =       dot-atom / quoted-string / obs-local-part

@@ -205,11 +234,12 @@
 	// 	(http://tools.ietf.org/html/rfc5322#section-3.4.1)

 	//

 	// Problem: need to distinguish between "first.last" and "first"."last"

-	// (i.e. one element or two). And I suck at regexes.

-	$dotArray	= /*. (array[int]string) .*/ preg_split('/\\.(?=(?:[^\\"]*\\"[^\\"]*\\")*(?![^\\"]*\\"))/m', $localPart);

+	// (i.e. one element or two). And I suck at regular expressions.

+	$dotArray	= preg_split('/\\.(?=(?:[^\\"]*\\"[^\\"]*\\")*(?![^\\"]*\\"))/m', $localPart);

 	$partLength	= 0;

 

-	foreach ($dotArray as $element) {

+	foreach ($dotArray as $arrayMember) {

+		$element = (string) $arrayMember;

 		// Remove any leading or trailing FWS

 		$new_element = preg_replace("/^$FWS|$FWS\$/", '', $element);

 		if ($warn && ($element !== $new_element)) $return_status = ISEMAIL_FWS;	// FWS is unlikely in the real world

@@ -217,8 +247,8 @@
 // version 2.3: Warning condition added

 		$elementLength	= strlen($element);

 

-		if ($elementLength === 0)								return $diagnose ? ISEMAIL_ZEROLENGTHELEMENT	: false;	// Can't have empty element (consecutive dots or dots at the start or end)

-// revision 1.15: Speed up the test and get rid of "unitialized string offset" notices from PHP

+		if ($elementLength === 0)								if ($diagnose) return ISEMAIL_ZEROLENGTHELEMENT;	else return false;	// Can't have empty element (consecutive dots or dots at the start or end)

+// revision 1.15: Speed up the test and get rid of "uninitialized string offset" notices from PHP

 

 		// We need to remove any valid comments (i.e. those at the start or end of the element)

 		if ($element[0] === '(') {

@@ -227,7 +257,7 @@
 			$indexBrace = strpos($element, ')');

 			if ($indexBrace !== false) {

 				if (preg_match('/(?<!\\\\)[\\(\\)]/', substr($element, 1, $indexBrace - 1)) > 0)

-													return $diagnose ? ISEMAIL_BADCOMMENT_START	: false;	// Illegal characters in comment

+													if ($diagnose) return ISEMAIL_BADCOMMENT_START;		else return false;	// Illegal characters in comment

 				$element	= substr($element, $indexBrace + 1, $elementLength - $indexBrace - 1);

 				$elementLength	= strlen($element);

 			}

@@ -239,7 +269,7 @@
 			$indexBrace = strrpos($element, '(');

 			if ($indexBrace !== false) {

 				if (preg_match('/(?<!\\\\)(?:[\\(\\)])/', substr($element, $indexBrace + 1, $elementLength - $indexBrace - 2)) > 0)

-													return $diagnose ? ISEMAIL_BADCOMMENT_END	: false;	// Illegal characters in comment

+													if ($diagnose) return ISEMAIL_BADCOMMENT_END;		else return false;	// Illegal characters in comment

 				$element	= substr($element, 0, $indexBrace);

 				$elementLength	= strlen($element);

 			}

@@ -263,10 +293,10 @@
 // version 2.0: Warning condition added

 			// Remove any FWS

 			$element = preg_replace("/(?<!\\\\)$FWS/", '', $element);	// A warning condition, but we've already raised ISEMAIL_QUOTEDSTRING

-			// My regex skillz aren't up to distinguishing between \" \\" \\\" \\\\" etc.

+			// My regular expression skills aren't up to distinguishing between \" \\" \\\" \\\\" etc.

 			// So remove all \\ from the string first...

 			$element = preg_replace('/\\\\\\\\/', ' ', $element);

-			if (preg_match('/(?<!\\\\|^)["\\r\\n\\x00](?!$)|\\\\"$|""/', $element) > 0)	return $diagnose ? ISEMAIL_UNESCAPEDDELIM	: false;	// ", CR, LF and NUL must be escaped

+			if (preg_match('/(?<!\\\\|^)["\\r\\n\\x00](?!$)|\\\\"$|""/', $element) > 0)	if ($diagnose) return ISEMAIL_UNESCAPEDDELIM;		else return false;	// ", CR, LF and NUL must be escaped

 // version 2.0: allow ""@example.com because it's technically valid

 		} else {

 			// Unquoted string tests:

@@ -277,7 +307,7 @@
 			//

 			// A zero-length element implies a period at the beginning or end of the

 			// local part, or two periods together. Either way it's not allowed.

-			if ($element === '')								return $diagnose ? ISEMAIL_EMPTYELEMENT		: false;	// Dots in wrong place

+			if ($element === '')								if ($diagnose) return ISEMAIL_EMPTYELEMENT;		else return false;	// Dots in wrong place

 

 			// Any ASCII graphic (printing) character other than the

 			// at-sign ("@"), backslash, double quote, comma, or square brackets may

@@ -286,12 +316,12 @@
 			// 	(http://tools.ietf.org/html/rfc3696#section-3)

 			//

 			// Any excluded characters? i.e. 0x00-0x20, (, ), <, >, [, ], :, ;, @, \, comma, period, "

-			if (preg_match('/[\\x00-\\x20\\(\\)<>\\[\\]:;@\\\\,\\."]/', $element) > 0)	return $diagnose ? ISEMAIL_UNESCAPEDSPECIAL	: false;	// These characters must be in a quoted string

+			if (preg_match('/[\\x00-\\x20\\(\\)<>\\[\\]:;@\\\\,\\."]/', $element) > 0)	if ($diagnose) return ISEMAIL_UNESCAPEDSPECIAL;		else return false;	// These characters must be in a quoted string

 			if ($warn && (preg_match('/^\\w+/', $element) === 0)) $return_status = ISEMAIL_UNLIKELYINITIAL;	// First character is an odd one

 		}

 	}

 

-	if ($partLength > 64)										return $diagnose ? ISEMAIL_LOCALTOOLONG		: false;	// Local part must be 64 characters or less

+	if ($partLength > 64)										if ($diagnose) return ISEMAIL_LOCALTOOLONG;		else return false;	// Local part must be 64 characters or less

 

 	// Now let's check the domain part...

 

@@ -307,6 +337,8 @@
 		$groupMax	= 8;

 // revision 2.1: new IPv6 testing strategy

 		$matchesIP	= array();

+		$colon		= ':';	// Revision 2.7: Daniel Marschall's new IPv6 testing strategy

+		$double_colon	= '::';

 

 		// Extract IPv4 part from the end of the address-literal (if there is one)

 		if (preg_match('/\\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/', $addressLiteral, $matchesIP) > 0) {

@@ -314,13 +346,13 @@
 

 			if ($index === 0) {

 				// Nothing there except a valid IPv4 address, so...

-				return ($diagnose) ? $return_status : true;

+				if ($diagnose) return $return_status; else return true;

 // version 2.0: return warning if one is set

 			} else {

 //-				// Assume it's an attempt at a mixed address (IPv6 + IPv4)

-//-				if ($addressLiteral[$index - 1] !== ':')				return $diagnose ? ISEMAIL_IPV4BADPREFIX	: false;	// Character preceding IPv4 address must be ':'

+//-				if ($addressLiteral[$index - 1] !== $colon)				if ($diagnose) return ISEMAIL_IPV4BADPREFIX;		else return false;	// Character preceding IPv4 address must be ':'

 // revision 2.1: new IPv6 testing strategy

-				if (substr($addressLiteral, 0, 5) !== 'IPv6:')				return $diagnose ? ISEMAIL_IPV6BADPREFIXMIXED	: false;	// RFC5321 section 4.1.3

+				if (substr($addressLiteral, 0, 5) !== 'IPv6:')				if ($diagnose) return ISEMAIL_IPV6BADPREFIXMIXED;	else return false;	// RFC5321 section 4.1.3

 //-

 //-				$IPv6		= substr($addressLiteral, 5, ($index === 7) ? 2 : $index - 6);

 //-				$groupMax	= 6;

@@ -329,39 +361,35 @@
 			}

 		} else {

 			// It must be an attempt at pure IPv6

-			if (substr($addressLiteral, 0, 5) !== 'IPv6:')					return $diagnose ? ISEMAIL_IPV6BADPREFIX	: false;	// RFC5321 section 4.1.3

+			if (substr($addressLiteral, 0, 5) !== 'IPv6:')					if ($diagnose) return ISEMAIL_IPV6BADPREFIX;		else return false;	// RFC5321 section 4.1.3

 			$IPv6 = substr($addressLiteral, 5);

 //-			$groupMax = 8;

 // revision 2.1: new IPv6 testing strategy

 		}

-//echo "\n<br /><pre>\$IPv6 = $IPv6</pre>\n"; // debug

-		$groupCount	= preg_match_all('/^[0-9a-fA-F]{0,4}|\\:[0-9a-fA-F]{0,4}|(.)/', $IPv6, $matchesIP);

-		$index		= strpos($IPv6,'::');

 

-//echo "\n<br /><pre>\$matchesIP[0] = " . var_export($matchesIP[0], true) . "</pre>\n"; // debug

+		$matchesIP	= explode($colon, $IPv6);	// Revision 2.7: Daniel Marschall's new IPv6 testing strategy

+		$groupCount	= count($matchesIP);

+		$index		= strpos($IPv6,$double_colon);

+

 		if ($index === false) {

 			// We need exactly the right number of groups

-			if ($groupCount !== $groupMax)							return $diagnose ? ISEMAIL_IPV6GROUPCOUNT	: false;	// RFC5321 section 4.1.3

+			if ($groupCount !== $groupMax)							if ($diagnose) return ISEMAIL_IPV6GROUPCOUNT;		else return false;	// RFC5321 section 4.1.3

 		} else {

-			if ($index !== strrpos($IPv6,'::'))						return $diagnose ? ISEMAIL_IPV6DOUBLEDOUBLECOLON : false;	// More than one '::'

+			if ($index !== strrpos($IPv6,$double_colon))					if ($diagnose) return ISEMAIL_IPV6DOUBLEDOUBLECOLON;	else return false;	// More than one '::'

 			if ($index === 0 || $index === (strlen($IPv6) - 2)) $groupMax++;	// RFC 4291 allows :: at the start or end of an address with 7 other groups in addition

-//echo "\n<br /><pre>\$groupMax = $groupMax</pre>\n"; // debug

-			if ($groupCount > $groupMax)							return $diagnose ? ISEMAIL_IPV6TOOMANYGROUPS	: false;	// Too many IPv6 groups in address

+			if ($groupCount > $groupMax)							if ($diagnose) return ISEMAIL_IPV6TOOMANYGROUPS;	else return false;	// Too many IPv6 groups in address

 			if ($groupCount === $groupMax) $return_status = ISEMAIL_SINGLEGROUPELISION;	// Eliding a single group with :: is deprecated by RFCs 5321 & 5952

 		}

 

 		// Check for single : at start and end of address

-		if (($matchesIP[0][0] === '') && ($matchesIP[0][1] !== ':'))				return $diagnose ? ISEMAIL_IPV6SINGLECOLONSTART	: false;	// Address starts with a single colon

-		if (($matchesIP[0][$groupCount - 1] === ':') && ($matchesIP[0][$groupCount - 2] !== ':')) return $diagnose ? ISEMAIL_IPV6SINGLECOLONEND	: false;	// Address ends with a single colon

+		// Revision 2.7: Daniel Marschall's new IPv6 testing strategy

+		if ((substr($IPv6, 0,  1)	=== $colon) && (substr($IPv6, 1,  1) !== $colon))	if ($diagnose) return ISEMAIL_IPV6SINGLECOLONSTART;	else return false;	// Address starts with a single colon

+		if ((substr($IPv6, -1)		=== $colon) && (substr($IPv6, -2, 1) !== $colon))	if ($diagnose) return ISEMAIL_IPV6SINGLECOLONEND;	else return false;	// Address ends with a single colon

 

 		// Check for unmatched characters

-		array_multisort($matchesIP[1], SORT_DESC);

-		if ($matchesIP[1][0] !== '') {

-//echo "\n<br /><pre>\$matchesIP[1] = " . var_export($matchesIP[1], true) . "</pre>\n"; // debug

-		return $diagnose ? ISEMAIL_IPV6BADCHAR		: false;	// Illegal characters in address

-} // debug

+		if (count(preg_grep('/^[0-9A-Fa-f]{0,4}$/', $matchesIP, PREG_GREP_INVERT)) !== 0)	if ($diagnose) return ISEMAIL_IPV6BADCHAR;		else return false;	// Illegal characters in address

 		// It's a valid IPv6 address, so...

-		return ($diagnose) ? $return_status : true;

+		if ($diagnose) return $return_status; else return true;

 // revision 2.1: bug fix: now correctly return warning status

 	} else {

 		// It's a domain name...

@@ -389,7 +417,7 @@
 		//

 		// RFC5321 precludes the use of a trailing dot in a domain name for SMTP purposes

 		// 	(http://tools.ietf.org/html/rfc5321#section-4.1.2)

-		$dotArray	= /*. (array[int]string) .*/ preg_split('/\\.(?=(?:[^\\"]*\\"[^\\"]*\\")*(?![^\\"]*\\"))/m', $domain);

+		$dotArray	= preg_split('/\\.(?=(?:[^\\"]*\\"[^\\"]*\\")*(?![^\\"]*\\"))/m', $domain);

 		$partLength	= 0;

 		$element	= ''; // Since we use $element after the foreach loop let's make sure it has a value

 // revision 1.13: Line above added because PHPLint now checks for Definitely Assigned Variables

@@ -397,7 +425,8 @@
 		if ($warn && (count($dotArray) === 1))	$return_status = ISEMAIL_TLD;	// The mail host probably isn't a TLD

 // version 2.0: downgraded to a warning

 

-		foreach ($dotArray as $element) {

+		foreach ($dotArray as $arrayMember) {

+			$element = (string) $arrayMember;

 			// Remove any leading or trailing FWS

 			$new_element	= preg_replace("/^$FWS|$FWS\$/", '', $element);

 			if ($warn && ($element !== $new_element)) $return_status = ISEMAIL_FWS;	// FWS is unlikely in the real world

@@ -408,8 +437,8 @@
 			// Each dot-delimited component must be of type atext

 			// A zero-length element implies a period at the beginning or end of the

 			// local part, or two periods together. Either way it's not allowed.

-			if ($elementLength === 0)							return $diagnose ? ISEMAIL_DOMAINEMPTYELEMENT	: false;	// Dots in wrong place

-// revision 1.15: Speed up the test and get rid of "unitialized string offset" notices from PHP

+			if ($elementLength === 0)							if ($diagnose) return ISEMAIL_DOMAINEMPTYELEMENT;	else return false;	// Dots in wrong place

+// revision 1.15: Speed up the test and get rid of "uninitialized string offset" notices from PHP

 

 			// Then we need to remove all valid comments (i.e. those at the start or end of the element

 			if ($element[0] === '(') {

@@ -418,7 +447,7 @@
 				$indexBrace = strpos($element, ')');

 				if ($indexBrace !== false) {

 					if (preg_match('/(?<!\\\\)[\\(\\)]/', substr($element, 1, $indexBrace - 1)) > 0)

-													return $diagnose ? ISEMAIL_BADCOMMENT_START	: false;	// Illegal characters in comment

+													if ($diagnose) return ISEMAIL_BADCOMMENT_START;		else return false;	// Illegal characters in comment

 // revision 1.17: Fixed name of constant (also spotted by turboflash - thanks!)

 					$element	= substr($element, $indexBrace + 1, $elementLength - $indexBrace - 1);

 					$elementLength	= strlen($element);

@@ -431,7 +460,7 @@
 				$indexBrace = strrpos($element, '(');

 				if ($indexBrace !== false) {

 					if (preg_match('/(?<!\\\\)(?:[\\(\\)])/', substr($element, $indexBrace + 1, $elementLength - $indexBrace - 2)) > 0)

-													return $diagnose ? ISEMAIL_BADCOMMENT_END	: false;	// Illegal characters in comment

+													if ($diagnose) return ISEMAIL_BADCOMMENT_END;		else return false;	// Illegal characters in comment

 // revision 1.17: Fixed name of constant (also spotted by turboflash - thanks!)

 					$element	= substr($element, 0, $indexBrace);

 					$elementLength	= strlen($element);

@@ -453,7 +482,7 @@
 			// separated by dots, and with a maximum total of 255

 			// octets.

 			// 	(http://tools.ietf.org/html/rfc1123#section-6.1.3.5)

-			if ($elementLength > 63)							return $diagnose ? ISEMAIL_DOMAINELEMENTTOOLONG	: false;	// Label must be 63 characters or less

+			if ($elementLength > 63)							if ($diagnose) return ISEMAIL_DOMAINELEMENTTOOLONG;	else return false;	// Label must be 63 characters or less

 

 			// Any ASCII graphic (printing) character other than the

 			// at-sign ("@"), backslash, double quote, comma, or square brackets may

@@ -466,24 +495,35 @@
 			// 	(http://tools.ietf.org/html/rfc3696#section-2)

 			//

 			// Any excluded characters? i.e. 0x00-0x20, (, ), <, >, [, ], :, ;, @, \, comma, period, "

-			if (preg_match('/[\\x00-\\x20\\(\\)<>\\[\\]:;@\\\\,\\."]|^-|-$/', $element) > 0) return $diagnose ? ISEMAIL_DOMAINBADCHAR	: false;	// Illegal character in domain name

+			if (preg_match('/[\\x00-\\x20\\(\\)<>\\[\\]:;@\\\\,\\."]|^-|-$/', $element) > 0) if ($diagnose) return ISEMAIL_DOMAINBADCHAR;		else return false;	// Illegal character in domain name

 		}

 

-		if ($partLength > 255) 									return $diagnose ? ISEMAIL_DOMAINTOOLONG	: false;	// Domain part must be 255 characters or less (http://tools.ietf.org/html/rfc1123#section-6.1.3.5)

+		if ($partLength > 255) 									if ($diagnose) return ISEMAIL_DOMAINTOOLONG;		else return false;	// Domain part must be 255 characters or less (http://tools.ietf.org/html/rfc1123#section-6.1.3.5)

 

 		if ($warn && (preg_match('/^[0-9]+$/', $element) > 0))	$return_status = ISEMAIL_TLDNUMERIC;	// TLD probably isn't all-numeric (http://www.apps.ietf.org/rfc/rfc3696.html#sec-2)

 // version 2.0: Downgraded to a warning

 

 		// Check DNS?

 		if ($diagnose && ($return_status === ISEMAIL_VALID) && $checkDNS && function_exists('checkdnsrr')) {

-			if (!(checkdnsrr($domain, 'A')))	$return_status = ISEMAIL_DOMAINNOTFOUND;	// 'A' record for domain can't be found

-			if (!(checkdnsrr($domain, 'MX')))	$return_status = ISEMAIL_MXNOTFOUND;		// 'MX' record for domain can't be found

+			// Revision 2.10: Amended DNS logic

+			// An A-record is not required unless there are no MX-records

+			// for a domain. Obvious when you think about it.

+			// 	(http://tools.ietf.org/html/rfc5321#section-5)

+			// 	(http://tools.ietf.org/html/rfc2181#section-10.3)

+			// 	(http://tools.ietf.org/html/rfc1035)

+			if (!(checkdnsrr($domain, 'MX'))) {

+				$result = @dns_get_record($domain, DNS_A);

+

+				if ((is_bool($result) && !(bool) $result))

+					$return_status = ISEMAIL_DOMAINNOTFOUND;	// Neither MX- nor A-record for domain can be found

+				else	$return_status = ISEMAIL_MXNOTFOUND;		// MX-record for domain can't be found

+			}

 		}

 	}

 

 	// Eliminate all other factors, and the one which remains must be the truth.

 	// 	(Sherlock Holmes, The Sign of Four)

-	return ($diagnose) ? $return_status : true;

+	if ($diagnose) return $return_status; else return true;

 // version 2.0: return warning if one is set

 }

 ?>