input := bytes.Repeat([]byte{'a'}, count)

	t.Run("small", func(t *testing.T) {
		got, err := ReadDataAt(bytes.NewReader(input), count, 0)
		if err != nil {
			t.Fatal(err)
		}
		if !bytes.Equal(got, input) {
			t.Errorf("got %v, want %v", got, input)
		}
	})

	t.Run("large", func(t *testing.T) {
		_, err := ReadDataAt(bytes.NewReader(input), 10<<30, 0)
		if err == nil {
			t.Error("large read succeeded unexpectedly")

	for _, prog := range x.f.Progs {
		if prog.Vaddr <= addr && addr <= prog.Vaddr+prog.Filesz-1 {
			n := prog.Vaddr + prog.Filesz - addr
			if n > size {
				n = size
			}
			return saferio.ReadDataAt(prog, n, int64(addr-prog.Vaddr))
		}
	}
	return nil, errUnrecognizedFormat
}

func (x *elfExe) DataStart() (uint64, uint64) {
	for _, s := range x.f.Sections {
		if s.Name == ".go.buildinfo" {

			return nil, err
		}
		buf = append(buf, buf1[:next]...)
		n -= next
	}
	return buf, nil
}

// ReadDataAt reads n bytes from the input stream at off, but avoids
// allocating all n bytes if n is large. This avoids crashing the program
// by allocating all n bytes in cases where n is incorrect.
func ReadDataAt(r io.ReaderAt, n uint64, off int64) ([]byte, error) {
	if int64(n) < 0 || n != uint64(int(n)) {

				return nil, err
			}
			strtab, err := saferio.ReadDataAt(r, uint64(hdr.Strsize), int64(hdr.Stroff))
			if err != nil {
				return nil, err
			}
			var symsz int
			if f.Magic == Magic64 {
				symsz = 16
			} else {
				symsz = 12
			}
			symdat, err := saferio.ReadDataAt(r, uint64(hdr.Nsyms)*uint64(symsz), int64(hdr.Symoff))
			if err != nil {
				return nil, err

// Data reads and returns the contents of the PE section s.
//
// If s.Offset is 0, the section has no contents,
// and Data will always return a non-nil error.
func (s *Section) Data() ([]byte, error) {
	return saferio.ReadDataAt(s.sr, uint64(s.Size), 0)
}

// Open returns a new ReadSeeker reading the PE section s.
//
// If s.Offset is 0, the section has no contents, and all calls
// to the returned reader will return a non-nil error.

	// with other clients.
	io.ReaderAt
	sr *io.SectionReader
}

// Data reads and returns the contents of the Plan 9 a.out section.
func (s *Section) Data() ([]byte, error) {
	return saferio.ReadDataAt(s.sr, uint64(s.Size), 0)
}

// Open returns a new ReadSeeker reading the Plan 9 a.out section.
func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }

		return nil, err
	}
	// The first 4 bytes contain the length (in bytes).
	var l uint32
	if err := binary.Read(sr, binary.BigEndian, &l); err != nil {
		return nil, err
	}
	if l > 4 {
		st, err := saferio.ReadDataAt(sr, uint64(l), int64(offset))
		if err != nil {
			return nil, err
		}
		f.StringTable = st
	}

	// Read section headers
	if _, err := sr.Seek(int64(hdrsz)+int64(opthdr), io.SeekStart); err != nil {

	}
	if phnum > 0 && phentsize < wantPhentsize {
		return nil, &FormatError{0, "invalid ELF phentsize", phentsize}
	}

	// Read program headers
	f.Progs = make([]*Prog, phnum)
	phdata, err := saferio.ReadDataAt(sr, uint64(phnum)*uint64(phentsize), phoff)
	if err != nil {
		return nil, err
	}
	for i := 0; i < phnum; i++ {
		off := uintptr(i) * uintptr(phentsize)
		p := new(Prog)
		switch f.Class {