partIdx := latestMeta.Parts[partIndex].Index
			partChecksums := latestMeta.Parts[partIndex].Checksums
			tillOffset := erasure.ShardFileOffset(0, partSize, partSize)
			readers := make([]io.ReaderAt, len(latestDisks))
			prefer := make([]bool, len(latestDisks))
			checksumAlgo := erasureInfo.GetChecksumInfo(partNumber).Algorithm
			for i, disk := range latestDisks {
				if disk == OfflineDisk {
					continue

				f, err := os.Open(file)
				if err != nil {
					return err
				}
				if st, err := f.Stat(); err == nil {
					sz = st.Size()
				}
				defer f.Close()
				r = f
			}
			if ra, ok := r.(io.ReaderAt); ok && strings.HasSuffix(file, ".zip") {
				zr, err := zip.NewReader(ra, sz)
				if err != nil {
					return err
				}
				for _, file := range zr.File {
					if file.FileInfo().IsDir() {
						continue

			partLength = length - totalBytesRead
		}

		tillOffset := erasure.ShardFileOffset(partOffset, partLength, partSize)
		// Get the checksums of the current part.
		readers := make([]io.ReaderAt, len(onlineDisks))
		prefer := make([]bool, len(onlineDisks))
		for index, disk := range onlineDisks {
			if disk == OfflineDisk {
				continue
			}
			if !metaArr[index].IsValid() {
				continue
			}

pkg io, type ReadWriter interface, Write([]uint8) (int, error)
pkg io, type Reader interface { Read }
pkg io, type Reader interface, Read([]uint8) (int, error)
pkg io, type ReaderAt interface { ReadAt }
pkg io, type ReaderAt interface, ReadAt([]uint8, int64) (int, error)
pkg io, type ReaderFrom interface { ReadFrom }
pkg io, type ReaderFrom interface, ReadFrom(Reader) (int64, error)
pkg io, type RuneReader interface { ReadRune }

	}

	// Verify it is a regular file, otherwise subsequent Seek is
	// undefined.
	if !st.Mode().IsRegular() {
		return 0, errIsNotRegular
	}

	if verifier == nil {
		n, err = file.ReadAt(buffer, offset)
		return int64(n), err
	}

	h := verifier.algorithm.New()
	if _, err = io.Copy(h, io.LimitReader(file, offset)); err != nil {
		return 0, err
	}