Browser detection broken

I’m using Opera quite a bit on my site and found the plugin never detected Opera but instead classified it as “Unknown”.

The following code is in statistics.class.php:

public function get_UserAgent() {

			static $agent = null;

			if ( empty($agent) ) {
				$agent = $_SERVER['HTTP_USER_AGENT'];

				if ( stripos($agent, 'Firefox') ) {
					$agent = 'Firefox';
				} elseif ( stripos($agent, 'MSIE') ) {
					$agent = 'IE';
				} elseif ( stripos($agent, 'iPad') ) {
					$agent = 'Ipad';
				} elseif ( stripos($agent, 'Android') ) {
					$agent = 'Android';
				} elseif ( stripos($agent, 'Chrome') ) {
					$agent = 'Chrome';
				} elseif ( stripos($agent, 'Opera') ) {
					$agent = 'Opera';
				} elseif ( stripos($agent, 'Safari') ) {
					$agent = 'Safari';
				} else {
					$agent = 'unknown';
				}
			}

			return $agent;
		}

which is broken as stripos can return 0 which evals to false but is actually returning the fact the string was found at the first position in the string.

Also, the check for $agent being empty is redundent as it was just set to null the line before. A working version of the function is as follows:

public function get_UserAgent() {
			$agent = $_SERVER['HTTP_USER_AGENT'];

			if ( stripos($agent, 'Firefox') !== FALSE ) {
				$agent = 'Firefox';
			} elseif ( stripos($agent, 'MSIE') !== FALSE ) {
				$agent = 'IE';
			} elseif ( stripos($agent, 'iPad') !== FALSE ) {
				$agent = 'Ipad';
			} elseif ( stripos($agent, 'Android') !== FALSE ) {
				$agent = 'Android';
			} elseif ( stripos($agent, 'Chrome') !== FALSE ) {
				$agent = 'Chrome';
			} elseif ( stripos($agent, 'Opera') !== FALSE ) {
				$agent = 'Opera';
			} elseif ( stripos($agent, 'Safari') !== FALSE ) {
				$agent = 'Safari';
			} else {
				$agent = 'unknown';
			}

			return $agent;
		}

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