//   - Exactly 0 bytes are read and EOF is hit.
//   - Exactly 1 block of zeros is read and EOF is hit.
//   - At least 2 blocks of zeros are read.
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
	}

	rc io.ReadCloser
	mu sync.Mutex
}

func (pr *syncReadCloser) Read(p []byte) (n int, err error) {
	// This ensures that Close will block until Read has completed.
	// This allows another goroutine to close the reader.
	pr.mu.Lock()
	defer pr.mu.Unlock()
	if pr.rc == nil {
		return 0, io.EOF
	}
	return pr.rc.Read(p)
}

func (pr *syncReadCloser) Close() error {
	pr.mu.Lock()

	bufCount := 0
	for _, b := range buf {
		if len(b) > 0 {
			bufCount++
		}
	}
	return bufCount >= p.dataBlocks
}

// Read reads from readers in parallel. Returns p.dataBlocks number of bufs.
func (p *parallelReader) Read(dst [][]byte) ([][]byte, error) {
	newBuf := dst
	if len(dst) != len(p.readers) {
		newBuf = make([][]byte, len(p.readers))
	} else {
		for i := range newBuf {

// data returned to just N bytes. Each call to Read
// updates N to reflect the new amount remaining.
// Read returns EOF when N <= 0 or when the underlying R returns EOF.
type HardLimitedReader struct {
	R io.Reader // underlying reader
	N int64     // max bytes remaining
}

func (l *HardLimitedReader) Read(p []byte) (n int, err error) {
	if l.N < 0 {
		return 0, ErrOverread
	}

		Method: Deflate,
		Mode:   0755 | fs.ModeDevice | fs.ModeCharDevice,
	},
}

func TestWriter(t *testing.T) {
	largeData := make([]byte, 1<<17)
	if _, err := rand.Read(largeData); err != nil {
		t.Fatal("rand.Read failed:", err)
	}
	writeTests[1].Data = largeData
	defer func() {
		writeTests[1].Data = nil
	}()

	// write a zip file
	buf := new(bytes.Buffer)
	w := NewWriter(buf)

	recordDelimiter []byte
	oneByte         []byte
	useOneByte      bool
}

func (rr *recordTransform) Read(p []byte) (n int, err error) {
	if rr.useOneByte {
		p[0] = rr.oneByte[0]
		rr.useOneByte = false
		n, err = rr.reader.Read(p[1:])
		n++
	} else {
		n, err = rr.reader.Read(p)
	}

	if err != nil {
		return n, err
	}

	// Do nothing if record-delimiter is already newline.

		}
	}
	return &Reader{
		src:      r,
		md5:      md5.New(),
		checksum: etag,
	}
}

// Read reads up to len(p) bytes from the underlying
// io.Reader as specified by the io.Reader interface.
func (r *Reader) Read(p []byte) (int, error) {
	n, err := r.src.Read(p)
	r.readN += int64(n)
	r.md5.Write(p[:n])

	if err == io.EOF && len(r.checksum) != 0 {

	defer xioutil.ODirectPoolSmall.Put(bufp)

	for left > 0 {
		// Read expected hash...
		h.Reset()
		n, err := io.ReadFull(r, hashBuf)
		if err != nil {
			// Read's failed for object with right size, file is corrupt.
			return err
		}
		// Subtract hash length..
		left -= int64(n)
		if left < shardSize {
			shardSize = left
		}

		read, err := io.CopyBuffer(h, io.LimitReader(r, shardSize), *bufp)

// reads in Scanner.Scan.
type slowReader struct {
	max int
	buf io.Reader
}

func (sr *slowReader) Read(p []byte) (n int, err error) {
	if len(p) > sr.max {
		p = p[0:sr.max]
	}
	return sr.buf.Read(p)
}

// genLine writes to buf a predictable but non-trivial line of text of length
// n, including the terminal newline and an occasional carriage return.

}

type firstByteRecorder struct {
	t *time.Time
	r io.Reader
}

func (f *firstByteRecorder) Read(p []byte) (n int, err error) {
	if f.t != nil || len(p) == 0 {
		return f.r.Read(p)
	}
	// Read a single byte.
	n, err = f.r.Read(p[:1])
	if n > 0 {
		t := time.Now()
		f.t = &t
	}
	return n, err
}

// Runs the speedtest on local MinIO process.