rsc.offset = rsc.size + offset
	}
	if rsc.offset < 0 {
		return rsc.offset, errors.New("seek to invalid negative offset")
	}
	if rsc.offset >= rsc.size {
		return rsc.offset, errors.New("seek past end of object")
	}
	if rsc.reader != nil {
		_ = rsc.reader.Close()
		rsc.reader = nil
	}
	return rsc.offset, nil
}

// Read call to implement io.Reader

	buf        []byte          // Holds bit-rot verified data
}

func (b *wholeBitrotReader) ReadAt(buf []byte, offset int64) (n int, err error) {
	if b.buf == nil {
		b.buf = make([]byte, b.tillOffset-offset)
		if _, err := b.disk.ReadFile(context.TODO(), b.volume, b.filePath, offset, b.buf, b.verifier); err != nil {
			return 0, err
		}
	}

func (d *naughtyDisk) ReadFile(ctx context.Context, volume string, path string, offset int64, buf []byte, verifier *BitrotVerifier) (n int64, err error) {
	if err := d.calcError(); err != nil {
		return 0, err
	}
	return d.disk.ReadFile(ctx, volume, path, offset, buf, verifier)
}

func (d *naughtyDisk) ReadFileStream(ctx context.Context, volume, path string, offset, length int64) (io.ReadCloser, error) {
	if err := d.calcError(); err != nil {

	}

	// To generate random offset/length.
	r := rand.New(rand.NewSource(UTCNow().UnixNano()))

	buf := &bytes.Buffer{}

	// Verify erasure.Decode() for random offsets and lengths.
	for i := 0; i < iterations; i++ {
		offset := r.Int63n(length)
		readLen := r.Int63n(length - offset)

		expected := data[offset : offset+readLen]

		// Get the checksums of the current part.

	for _, block := range enBlocks[:dataBlocks] {
		// Skip blocks until we have reached our offset.
		if offset >= int64(len(block)) {
			// Decrement offset.
			offset -= int64(len(block))
			continue
		}

		// Skip until offset.
		block = block[offset:]

		// Reset the offset for next iteration to read everything
		// from subsequent blocks.
		offset = 0

		// We have written all the blocks, write the last remaining block.

	return p.storage.ListDir(ctx, origvolume, volume, dirPath, count)
}

// Legacy API - does not have any deadlines
func (p *xlStorageDiskIDCheck) ReadFile(ctx context.Context, volume string, path string, offset int64, buf []byte, verifier *BitrotVerifier) (n int64, err error) {
	ctx, done, err := p.TrackDiskHealth(ctx, storageMetricReadFile, volume, path)
	if err != nil {
		return 0, err
	}
	defer done(&err)

			if typ.Is(ChecksumIncludesMultipart) {
				wantLen := int(t) * length
				if len(b) < wantLen {
					break
				}
				// Read part checksum
				if part > 0 && uint64(part) <= t {
					offset := (part - 1) * length
					partCs := b[offset:]
					cs = base64.StdEncoding.EncodeToString(partCs[:length])
				}
				b = b[wantLen:]
			}
		} else if part > 1 {
			// For non-multipart, checksum is part 1.
			cs = ""
		}

}

// ObjectToPartOffset - translate offset of an object to offset of its individual part.
func (fi FileInfo) ObjectToPartOffset(ctx context.Context, offset int64) (partIndex int, partOffset int64, err error) {
	if offset == 0 {
		// Special case - if offset is 0, then partIndex and partOffset are always 0.
		return 0, 0, nil
	}
	partOffset = offset
	// Seek until object offset maps to a particular part offset.

		}
		o, l, err := rs.GetOffsetLength(resourceSize)
		if err != nil {
			t.Errorf("unexpected err: %v", err)
		}
		if o != testCase.expOffset || l != testCase.expLength {
			t.Errorf("Case %d: got bad offset/length: %d,%d expected: %d,%d",
				i, o, l, testCase.expOffset, testCase.expLength)
		}
	}

	unparsableRangeSpecs := []string{
		"bytes=-",
		"bytes==",
		"bytes==1-10",
		"bytes=",
		"bytes=aa",

}

// DecryptSinglePart decrypts an io.Writer which must an object
// uploaded with the single-part PUT API. The offset and length
// specify the requested range.
func DecryptSinglePart(w io.Writer, offset, length int64, key ObjectKey) io.WriteCloser {
	const PayloadSize = 1 << 16 // DARE 2.0
	w = ioutil.LimitedWriter(w, offset%PayloadSize, length)

	decWriter, err := sio.DecryptWriter(w, sio.Config{Key: key[:], CipherSuites: fips.DARECiphers()})