}
	writeSecSize(ctxt, sizeOffset2)

	writeSecSize(ctxt, sizeOffset)
}

type nameWriter interface {
	io.ByteWriter
	io.Writer
}

func writeI32Const(w io.ByteWriter, v int32) {
	w.WriteByte(0x41) // i32.const
	writeSleb128(w, int64(v))
}

func writeI64Const(w io.ByteWriter, v int64) {
	w.WriteByte(0x42) // i64.const
	writeSleb128(w, v)
}

func writeName(w nameWriter, name string) {

// seek to one byte before the current offset.
type ByteScanner interface {
	ByteReader
	UnreadByte() error
}

// ByteWriter is the interface that wraps the WriteByte method.
type ByteWriter interface {
	WriteByte(c byte) error
}

// RuneReader is the interface that wraps the ReadRune method.
//
// ReadRune reads a single encoded Unicode character

func log2(x int) int {
	for i, v := range log2Lookup {
		if x <= v {
			return i
		}
	}
	return -1
}

// writer is a buffered writer.
type writer interface {
	Flush() error
	io.Writer
	io.ByteWriter
}

// encoder encodes an image to the GIF format.
type encoder struct {
	// w is the writer to write to. err is the first error encountered during
	// writing. All attempted writes after the first error become no-ops.

func init() {
	for i, s := range theHuffmanSpec {
		theHuffmanLUT[i].init(s)
	}
}

// writer is a buffered writer.
type writer interface {
	Flush() error
	io.Writer
	io.ByteWriter
}

// encoder encodes an image to the JPEG format.
type encoder struct {
	// w is the writer to write to. err is the first error encountered during

		panic("align: bad op")
	}
}

func writeUleb128(w io.ByteWriter, v uint64) {
	if v < 128 {
		w.WriteByte(uint8(v))
		return
	}
	more := true
	for more {
		c := uint8(v & 0x7f)
		v >>= 7
		more = v != 0
		if more {
			c |= 0x80
		}
		w.WriteByte(c)
	}
}

func writeSleb128(w io.ByteWriter, v int64) {
	more := true
	for more {
		c := uint8(v & 0x7f)

	// w is the buffered io.Writer to write the request to. It
	// fails exactly once on its Nth Write call, as controlled by
	// failAfter. It also tracks the number of calls in
	// writeCount.
	w := struct {
		io.ByteWriter // to avoid being wrapped by a bufio.Writer
		io.Writer
	}{
		nil,
		writerFunc(func(p []byte) (n int, err error) {
			writeCount++
			if failAfter == 0 {
				err = errFail
			}
			failAfter--

	if p.closed && p.err == nil {
		p.err = errors.New("use of closed Encoder")
	}
	if p.err == nil {
		n, p.err = p.w.WriteString(s)
	}
	return n, p.err
}

// WriteByte implements io.ByteWriter
func (p *printer) WriteByte(c byte) error {
	if p.closed && p.err == nil {
		p.err = errors.New("use of closed Encoder")
	}
	if p.err == nil {
		p.err = p.w.WriteByte(c)
	}
	return p.err
}

	"sync"
	"testing"
	"time"
)

func TestRingBuffer_interface(t *testing.T) {
	rb := New(1)
	var _ io.Writer = rb
	var _ io.Reader = rb
	// var _ io.StringWriter = rb
	var _ io.ByteReader = rb
	var _ io.ByteWriter = rb
}

func TestRingBuffer_Write(t *testing.T) {
	rb := New(64)

	// check empty or full
	if !rb.IsEmpty() {
		t.Fatalf("expect IsEmpty is true but got false")
	}
	if rb.IsFull() {