PHP - Get a users first name from the full name

fullNameToFirstName.php

<?php

/**
 * Get a users first name from the full name
 * or return the full name if first name cannot be found
 * e.g. 
 * James Smith 	    -> James
 * James C. Smith   -> James
 * Mr James Smith   -> James
 * Mr Smith 	    -> Mr Smith
 * Mr J Smith 	    -> Mr J Smith
 * Mr J. Smith 	    -> Mr J. Smith
 * 
 * @param string $fullName
 * @param bool   $checkFirstNameLength Should we make sure it doesn't just return "J" as a name? Defaults to TRUE.
 * 
 * @return string 
 */
function fullNameToFirstName($fullName, $checkFirstNameLength=TRUE)
{
	// Split out name so we can quickly grab the first name part
	$nameParts = explode(' ', $fullName);
	$firstName = $nameParts[0];

	// If the first part of the name is a prefix, then find the name differently
	if(in_array(strtolower($firstName), array('mr', 'ms', 'mrs', 'miss', 'dr'))) {
		if($nameParts[2]!='') {
			// E.g. Mr James Smith -> James
			$firstName = $nameParts[1];
		} else {
			// e.g. Mr Smith (no first name given)
			$firstName = $fullName;
		}
	}

	// make sure the first name is not just "J", e.g. "J Smith" or "Mr J Smith" or even "Mr J. Smith"
	if($checkFirstNameLength && strlen($firstName)<3) {
		$firstName = $fullName;
	}
	return $firstName;
}