// The result is unaffected by any method calls except [Reader.Reset].
func (r *Reader) Size() int64 { return int64(len(r.s)) }

// Read implements the [io.Reader] interface.
func (r *Reader) Read(b []byte) (n int, err error) {
	if r.i >= int64(len(r.s)) {
		return 0, io.EOF
	}
	r.prevRune = -1
	n = copy(b, r.s[r.i:])
	r.i += int64(n)
	return
}

}

func (r *checksumReader) Read(b []byte) (n int, err error) {
	if r.err != nil {
		return 0, r.err
	}
	n, err = r.rc.Read(b)
	r.hash.Write(b[:n])
	r.nread += uint64(n)
	if r.nread > r.f.UncompressedSize64 {
		return 0, ErrFormat
	}
	if err == nil {
		return
	}
	if err == io.EOF {
		if r.nread != r.f.UncompressedSize64 {
			return 0, io.ErrUnexpectedEOF
		}

		sparseMap = sparseMap[2:]
	}
	return spd, nil
}

// Read reads from the current file in the tar archive.
// It returns (0, io.EOF) when it reaches the end of that file,
// until [Next] is called to advance to the next file.
//
// If the current file is sparse, then the regions marked as a hole
// are read back as NUL-bytes.
//
// Calling Read on special types like [TypeLink], [TypeSymlink], [TypeChar],