+ /**
+ * Convert a Range header value to an absolute (start, end) range tuple
+ *
+ * @param string $range Range header value
+ * @param integer $size File size
+ * @return array|string Returns error string on failure (start, end, length)
+ * @since 1.24
+ */
+ public static function parseRange( $range, $size ) {
+ $m = [];
+ if ( preg_match( '#^bytes=(\d*)-(\d*)$#', $range, $m ) ) {
+ list( , $start, $end ) = $m;
+ if ( $start === '' && $end === '' ) {
+ $absRange = [ 0, $size - 1 ];
+ } elseif ( $start === '' ) {
+ $absRange = [ $size - $end, $size - 1 ];
+ } elseif ( $end === '' ) {
+ $absRange = [ $start, $size - 1 ];
+ } else {
+ $absRange = [ $start, $end ];
+ }
+ if ( $absRange[0] >= 0 && $absRange[1] >= $absRange[0] ) {
+ if ( $absRange[0] < $size ) {
+ $absRange[1] = min( $absRange[1], $size - 1 ); // stop at EOF
+ $absRange[2] = $absRange[1] - $absRange[0] + 1;
+ return $absRange;
+ } elseif ( $absRange[0] == 0 && $size == 0 ) {
+ return 'unrecognized'; // the whole file should just be sent
+ }
+ }
+ return 'invalid';
+ }
+ return 'unrecognized';