wikimedia / mediawiki

			$op = $x['op'];

			++$p;

			switch ( $op ) {

			case self::XDL_BDOP_INS:

				$x = unpack( 'Csize', substr( $diff, $p, 1 ) );

				$p++;

				$out .= substr( $diff, $p, $x['size'] );

				$p += $x['size'];

				break;

			case self::XDL_BDOP_INSB:

				$x = unpack( 'Vcsize', substr( $diff, $p, 4 ) );

				$p += 4;

				$out .= substr( $diff, $p, $x['size'] );

				$p += $x['size'];

				break;

			case self::XDL_BDOP_INSB:

				$x = unpack( 'Vcsize', substr( $diff, $p, 4 ) );

				$p += 4;

				$out .= substr( $diff, $p, $x['csize'] );

				$p += $x['csize'];

				break;

			case self::XDL_BDOP_CPY:

				$x = unpack( 'Voff/Vcsize', substr( $diff, $p, 8 ) );

				$p += 8;

				$out .= substr( $diff, $p, $x['csize'] );

				$p += $x['csize'];

				break;

			case self::XDL_BDOP_CPY:

				$x = unpack( 'Voff/Vcsize', substr( $diff, $p, 8 ) );

				$p += 8;

				$out .= substr( $base, $x['off'], $x['csize'] );

				break;

			default:

				wfDebug( __METHOD__ . ": invalid op\n" );

				return false;