}
}

// syncReadCloser will wrap a readcloser and make it safe to call Close while
// reads are running.
type syncReadCloser struct {
	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

type Reader struct {
	s        []byte
	i        int64 // current reading index
	prevRune int   // index of previous rune; or < 0
}

// Len returns the number of bytes of the unread portion of the
// slice.
func (r *Reader) Len() int {
	if r.i >= int64(len(r.s)) {
		return 0
	}
	return int(int64(len(r.s)) - r.i)
}

// Size returns the original length of the underlying byte slice.

	}

	var value interface{}
	switch val := v.(type) {
	case []byte:
		// TODO: only strings are supported in s3select output (not
		// binary arrays) - perhaps we need to check the annotation to
		// ensure it's UTF8 encoded.
		value = string(val)
	case [12]byte:
		// TODO: This is returned for the parquet INT96 type. We just
		// treat it same as []byte (but AWS S3 treats it as a large int)
		// - fix this later.

}

// UUIDHash - use uuid to make md5sum
type UUIDHash struct {
	uuid []byte
}

// Write -  implement hash.Hash Write
func (u UUIDHash) Write(p []byte) (n int, err error) {
	return len(p), nil
}

// Sum -  implement md5.Sum
func (u UUIDHash) Sum(b []byte) []byte {
	return u.uuid
}

// Reset -  implement hash.Hash Reset
func (u UUIDHash) Reset() {
	return
}

			sr.sp = sr.sp[1:] // Ensure last fragment always remains
		}
	}

	// If the last fragment is a hole, then seek to 1-byte before EOF, and
	// write a single byte to ensure the file is the right size.
	if writeLastByte && err == nil {
		_, err = ws.Write([]byte{0})
		sr.pos++
	}

	n = sr.pos - pos0
	switch {
	case err == io.EOF:

}

// safeCloser will wrap a Reader as a ReadCloser.
// It is safe to call Close while the reader is being used.
type safeCloser struct {
	closed uint32
	r      io.Reader
}

func (s *safeCloser) Read(p []byte) (n int, err error) {
	if atomic.LoadUint32(&s.closed) == 1 {
		return 0, io.EOF
	}
	n, err = s.r.Read(p)
	if atomic.LoadUint32(&s.closed) == 1 {
		return 0, io.EOF
	}
	return n, err
}

		r.err = io.EOF
	}
	return r.readCloser.Close()
}

// nextSplit will attempt to skip a number of bytes and
// return the buffer until the next newline occurs.
// The last block will be sent along with an io.EOF.
func (r *Reader) nextSplit(skip int, dst []byte) ([]byte, error) {
	if cap(dst) < skip {
		dst = make([]byte, 0, skip+1024)
	}
	dst = dst[:skip]
	if skip > 0 {
		n, err := io.ReadFull(r.buf, dst)

	// look for directoryEndSignature in the last 1k, then in the last 65k
	var buf []byte
	var directoryEndOffset int64
	for i, bLen := range []int64{1024, 65 * 1024} {
		if bLen > size {
			bLen = size
		}
		buf = make([]byte, int(bLen))
		if _, err := r.ReadAt(buf, size-bLen); err != nil && err != io.EOF {
			return nil, 0, err
		}

// result in a different checksum.
func (r *Reader) MD5Current() []byte {
	if r.disableMD5 {
		return r.checksum
	}
	return r.ETag()[:]
}

// SHA256 returns the SHA256 checksum set as reference value.
//
// It corresponds to the checksum that is expected and
// not the actual SHA256 checksum of the content.
func (r *Reader) SHA256() []byte {
	return r.contentSHA256
}

// Read implements a throttled read
func (r *MonitoredReader) Read(buf []byte) (n int, err error) {
	if r.throttle == nil {
		return r.r.Read(buf)
	}
	if r.lastErr != nil {
		err = r.lastErr
		return
	}
	b := r.throttle.Burst()  // maximum available tokens
	need := len(buf)         // number of bytes requested by caller
	hdr := r.opts.HeaderSize // remaining header bytes
	var tokens int           // number of tokens to request