$memLimit = ini_get( 'memory_limit' );
if ($memLimit != '')
{
    switch ( $memLimit{strlen( $memLimit ) - 1} )
    {
        case 'G':
            $memLimit *= 1024;
        case 'M':
            $memLimit *= 1024;
        case 'K':
            $memLimit *= 1024;
    }
    if ( $memLimit != -1 && $memLimit < 44040192) /* 42*1024*1024 */
    {
        @ini_set( 'memory_limit', '42M' );
    }
}