// a bit brittle but cannot be addressed without a large change of the
	// algorithm in the os.(*File).readdir method.
	return n - len(b), nil
}

// Seek wraps syscall.Seek.
func (fd *FD) Seek(offset int64, whence int) (int64, error) {
	if err := fd.incref(); err != nil {
		return 0, err
	}
	defer fd.decref()
	// syscall.Filetype is a uint8 but we store it as a uint32 in SysFile in

func (r errorReader) ReadAt(p []byte, off int64) (n int, err error) {
	return 0, r.error
}

func (r errorReader) Seek(offset int64, whence int) (int64, error) {
	return 0, r.error
}

func (r errorReader) Close() error {
	return r.error
}

// readSeekerFromReader converts an io.Reader into an io.ReadSeeker.
// In general Seek may not be efficient, but it is optimized for
// common cases such as seeking to the end to find the length of the

			brOff, brErr := br.Seek(offset, whence)
			srOff, srErr := sr.Seek(offset, whence)
			if (brErr != nil) != (srErr != nil) || brOff != srOff {
				t.Errorf("For whence %d, offset %d: bytes.Reader.Seek = (%v, %v) != SectionReader.Seek = (%v, %v)",
					whence, offset, brOff, brErr, srErr, srOff)
			}
		}
	}

	// And verify we can just seek past the end and get an EOF

		return err
	}
	if err := cdr.readArgs(); err != nil {
		return err
	}
	// Seek past any padding to bring us up to a 4-byte boundary.
	if of, err := cdr.mr.Seek(0, io.SeekCurrent); err != nil {
		return err
	} else {
		rem := of % 4
		if rem != 0 {
			pad := 4 - rem
			if _, err := cdr.mr.Seek(pad, io.SeekCurrent); err != nil {
				return err
			}
		}
	}
	return nil
}

		// Restore stdout, get output and remove temporary file.
		os.Stdout = stdout
		var buf strings.Builder
		_, seekErr := f.Seek(0, io.SeekStart)
		_, readErr := io.Copy(&buf, f)
		out := buf.String()
		f.Close()
		os.Remove(f.Name())
		if seekErr != nil {
			fmt.Fprintf(os.Stderr, "testing: seek temp file: %v\n", seekErr)
			os.Exit(1)
		}
		if readErr != nil {
			fmt.Fprintf(os.Stderr, "testing: read temp file: %v\n", readErr)

	if err != io.EOF {
		t.Fatal("Read:", err)
	}
	if n != 0 {
		t.Fatal("Read:", n)
	}

	// Use seek to get the offset at the EOF.
	seeker := file.(io.Seeker)
	off, err := seeker.Seek(0, io.SeekCurrent)
	if err != nil {
		t.Fatal("Seek:", err)
	}
	if off != int64(len(want)) {
		t.Fatal("Seek:", off)
	}

	// Use ReadAt to read the entire file, ignoring the offset.
	at := file.(io.ReaderAt)

	if fh.PointerToSymbolTable <= 0 {
		return nil, nil
	}
	offset := fh.PointerToSymbolTable + COFFSymbolSize*fh.NumberOfSymbols
	_, err := r.Seek(int64(offset), io.SeekStart)
	if err != nil {
		return nil, fmt.Errorf("fail to seek to string table: %v", err)
	}
	var l uint32
	err = binary.Read(r, binary.LittleEndian, &l)
	if err != nil {
		return nil, fmt.Errorf("fail to read string table length: %v", err)

		gs2 := readStr(slr)
		if gs2 != s2 {
			t.Fatalf("readStr got %s want %s", gs2, s2)
		}
		if _, err := slr.Seek(4, io.SeekStart); err != nil {
			t.Fatal(err)
		}
		off := slr.Offset()
		if off != 4 {
			t.Fatalf("Offset() returned %d wanted 4", off)
		}
		g64 = slr.ReadUint64()
		if g64 != e64 {
			t.Fatalf("post-seek slr.ReadUint64() got %d want %d", g64, e64)
		}
	}
}

func appendUleb128(b []byte, v uint) []byte {

		// io.Seeker, but calling Seek always returns an error and performs
		// no action. Thus, we try an innocent seek to the current position
		// to see if Seek is really supported.
		pos1, err := sr.Seek(0, io.SeekCurrent)
		if pos1 >= 0 && err == nil {
			// Seek seems supported, so perform the real Seek.
			pos2, err := sr.Seek(n-1, io.SeekCurrent)
			if pos2 < 0 || err != nil {
				return err

		size, err := content.Seek(0, io.SeekEnd)
		if err != nil {
			return 0, errSeeker
		}
		_, err = content.Seek(0, io.SeekStart)
		if err != nil {
			return 0, errSeeker
		}
		return size, nil
	}
	serveContent(w, req, name, modtime, sizeFunc, content)
}

// errSeeker is returned by ServeContent's sizeFunc when the content
// doesn't seek properly. The underlying Seeker's error text isn't