// first read just those 4 bytes to see if it exists.
	if _, err := io.ReadFull(r, buf[:4]); err != nil {
		return err
	}
	off := 0
	maybeSig := readBuf(buf[:4])
	if maybeSig.uint32() != dataDescriptorSignature {
		// No data descriptor signature. Keep these four
		// bytes.
		off += 4
	}
	if _, err := io.ReadFull(r, buf[off:12]); err != nil {
		return err
	}
	b := readBuf(buf[:12])

func (tr *Reader) readHeader() (*Header, *block, error) {
	// Two blocks of zero bytes marks the end of the archive.
	if _, err := io.ReadFull(tr.r, tr.blk[:]); err != nil {
		return nil, nil, err // EOF is okay here; exactly 0 bytes read
	}
	if bytes.Equal(tr.blk[:], zeroBlock[:]) {
		if _, err := io.ReadFull(tr.r, tr.blk[:]); err != nil {
			return nil, nil, err // EOF is okay here; exactly 1 block of zeros read
		}

					t.Fatalf("entry %d, Next(): got %v, want %v", i, err, nil)
				}
				buf := make([]byte, tc.cnt)
				if _, err := io.ReadFull(tr, buf); err != nil {
					t.Fatalf("entry %d, ReadFull(): got %v, want %v", i, err, nil)
				}
				if string(buf) != tc.output {
					t.Fatalf("entry %d, ReadFull(): got %q, want %q", i, string(buf), tc.output)
				}
			}

			if _, err := tr.Next(); err != io.EOF {

		if err != nil {
			t.Fatalf("Test %d: failed to create ErasureStorage: %v", i, err)
		}
		data := make([]byte, test.size)
		if _, err = io.ReadFull(rand.Reader, data); err != nil {
			t.Fatalf("Test %d: failed to create random test data: %v", i, err)
		}
		buffer := make([]byte, test.blocksize, 2*test.blocksize)
		writers := make([]io.Writer, len(disks))

	if err != nil {
		t.Fatal("opening:", err)
	}
	rc.(*checksumReader).hash = fakeHash32{}
	for i := 0; i < chunks; i++ {
		_, err := io.ReadFull(rc, chunk)
		if err != nil {
			t.Fatal("read:", err)
		}
	}
	if frag := int(size % chunkSize); frag > 0 {
		_, err := io.ReadFull(rc, chunk[:frag])
		if err != nil {
			t.Fatal("read:", err)
		}
	}
	gotEnd, err := io.ReadAll(rc)
	if err != nil {

		if err != nil {
			t.Fatalf("Test %d: failed to create ErasureStorage: %v", i, err)
		}
		buffer := make([]byte, test.blocksize, 2*test.blocksize)

		data := make([]byte, test.data)
		if _, err = io.ReadFull(rand.Reader, data); err != nil {
			t.Fatalf("Test %d: failed to generate random test data: %v", i, err)
		}
		writers := make([]io.Writer, len(disks))
		for i, disk := range disks {
			if disk == OfflineDisk {

	if !s.IsValid(w, r) {
		return
	}
	volume := r.Form.Get(storageRESTVolume)
	filePath := r.Form.Get(storageRESTFilePath)

	buf := make([]byte, r.ContentLength)
	_, err := io.ReadFull(r.Body, buf)
	if err != nil {
		s.writeErrorResponse(w, err)
		return
	}
	err = s.getStorage().AppendFile(r.Context(), volume, filePath, buf)
	if err != nil {
		s.writeErrorResponse(w, err)
	}
}

		sz, err := r.mr.ReadStringHeader()
		if err != nil {
			r.err = err
			return err
		}
		if cap(tmp) < int(sz) {
			tmp = make([]byte, 0, sz+256)
		}
		tmp = tmp[:sz]
		_, err = r.mr.R.ReadFull(tmp)
		if err != nil {
			r.err = err
			return err
		}
		if string(tmp) >= s {
			r.current.name = string(tmp)
			r.current.metadata, r.err = r.mr.ReadBytes(nil)
			return r.err
		}

	var written int64
	for {
		buf := alignedBuf
		if totalSize > 0 {
			remaining := totalSize - written
			if remaining < int64(len(buf)) {
				buf = buf[:remaining]
			}
		}

		nr, err := io.ReadFull(r, buf)
		eof := errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF)
		if err != nil && !eof {
			return written, err
		}

		buf = buf[:nr]
		var (
			n  int
			un int
			nw int64

		values.Set(storageRESTBitrotHash, "")
	}
	respBody, err := client.callGet(ctx, storageRESTMethodReadFile, values, nil, -1)
	if err != nil {
		return 0, err
	}
	defer xhttp.DrainBody(respBody)
	n, err := io.ReadFull(respBody, buf)
	return int64(n), toStorageErr(err)
}

// ListDir - lists a directory.