PHP Validate mail body

something.php

<?php

/**
 * Make sure lines are right length in mail body
 * @param string mail body
 * @param int max line length (default 68)
 * @param bool only return bool instead of modified body (default false)
 * @return string|bool validated body
 */
function validateMailBody($sBody, $iMaxLen = 68, $bReturnBool = false)
{
    $bIsValid = preg_match('//u', $sBody);
    $aResult = [];
    foreach(preg_split("/\r\n|\n/", $sBody) as $sPart)
    {
        if (strlen($sPart) > $iMaxLen)
        {
            if ($bReturnBool)
            {
                $bIsValid = false;
                break;
            }
          
            $aResult = array_merge($aResult, str_split($sPart, $iMaxLen));
            continue;
        }

        $aResult[] = $sPart;
    }
    
    if ($bReturnBool)
    {
        return $bIsValid;
    }
  
    return implode("\r\n", $aResult);
}