Linking email addresses that aren't already linked

Question

I'm currently matching email addresses with the below regex (and linking them as mailto links):

/([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,64})/

However, I do not want to link anything that has already been linked before as a mailto link or within an existing link (eg. index.php?email=example@example.com) otherwise the link gets quite screwed up like the below:

<a href="mailto:<a href="mailto:example@example.com">example@example.com</a>"><a href="mailto:example@example.com">example@example.com</a></a>

Update

Here's an example of PHP I'm using to find the email addresses (sorry, didn't think it was required):

$input = "example@example.com<br><br><a href='mailto:example@example.com'>test email</a><br><br><a href='mailto:example@example.com'>example@example.com</a>";

$output = preg_replace("/([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,64})/i", "<a href='mailto:$1'>$1</a>", $input);

//output
<a href="mailto:example@example.com">example@example.com</a><br><br><a mailto:example@example.com'="" href="mailto:&lt;a href=">example@example.com</a>'&gt;test email<br><br><a mailto:example@example.com'="" href="mailto:&lt;a href=">example@example.com</a>'&gt;<a href="mailto:example@example.com">example@example.com</a>

Update 2

I also have a further regex question (if possible) - I also have the below regex to make all links target to a new window, however, i do not want anything mailto linked to go to a new window - is it possible to not target mailto links?

$output = preg_replace("/<(a)([^>]+)>/i", "<\\1 target=\"_blank\"\\2>", str_replace('target="_blank"', '', $output));

Answer 1

How about this regex?

/((?<!mailto:|=|[a-zA-Z0-9._%+-])[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.‌​-]+\.[a-zA-Z]{2,64}(?![a-zA-Z]|<\/[aA]>))/