var buf [8]byte
	binary.LittleEndian.PutUint64(buf[:], uint64(n))
	p.Write(buf[:])
}

func (c *chacha20poly1305) sealGeneric(dst, nonce, plaintext, additionalData []byte) []byte {
	ret, out := sliceForAppend(dst, len(plaintext)+poly1305.TagSize)
	ciphertext, tag := out[:len(plaintext)], out[len(plaintext):]
	if alias.InexactOverlap(out, plaintext) {
		panic("chacha20poly1305: invalid buffer overlap")
	}

	if !cpu.X86.HasSSSE3 {
		return c.sealGeneric(dst, nonce, plaintext, additionalData)
	}

	var state [16]uint32
	setupState(&state, &c.key, nonce)

	ret, out := sliceForAppend(dst, len(plaintext)+16)
	if alias.InexactOverlap(out, plaintext) {
		panic("chacha20poly1305: invalid buffer overlap")
	}
	chacha20Poly1305Seal(out[:], state[:], plaintext, additionalData)
	return ret
}

func (g *gcmAsm) Overhead() int {
	return g.tagSize
}

// sliceForAppend takes a slice and a requested number of bytes. It returns a
// slice with the contents of the given slice followed by that many bytes and a
// second slice that aliases into it and contains only the extra bytes. If the
// original slice has sufficient capacity then no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {

	return c.open(dst, nonce, ciphertext, additionalData)
}

// sliceForAppend takes a slice and a requested number of bytes. It returns a
// slice with the contents of the given slice followed by that many bytes and a
// second slice that aliases into it and contains only the extra bytes. If the
// original slice has sufficient capacity then no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {

func (g *gcmAsm) Overhead() int {
	return g.tagSize
}

// sliceForAppend takes a slice and a requested number of bytes. It returns a
// slice with the contents of the given slice followed by that many bytes and a
// second slice that aliases into it and contains only the extra bytes. If the
// original slice has sufficient capacity then no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {

	gcmInit(&g.productTable, hle)

	return g, nil
}

func (g *gcmAsm) NonceSize() int {
	return g.nonceSize
}

func (g *gcmAsm) Overhead() int {
	return g.tagSize
}

func sliceForAppend(in []byte, n int) (head, tail []byte) {
	if total := len(in) + n; cap(in) >= total {
		head = in[:total]
	} else {
		head = make([]byte, total)
		copy(head, in)
	}
	tail = head[len(in):]
	return
}

		}
		b = b[3:]
	}
	return f, nil
}

// sliceForAppend takes a slice and a requested number of bytes. It returns a
// slice with the contents of the given slice followed by that many bytes and a
// second slice that aliases into it and contains only the extra bytes. If the
// original slice has sufficient capacity then no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {

	byteorder.BePutUint32(ctr, byteorder.BeUint32(ctr)+1)
}

// sliceForAppend takes a slice and a requested number of bytes. It returns a
// slice with the contents of the given slice followed by that many bytes and a
// second slice that aliases into it and contains only the extra bytes. If the
// original slice has sufficient capacity then no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {

		}

		plaintext = payload[:n]
	}

	hc.incSeq()
	return plaintext, typ, nil
}

// sliceForAppend extends the input slice by n bytes. head is the full extended
// slice, while tail is the appended part. If the original slice has sufficient
// capacity no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {
	if total := len(in) + n; cap(in) >= total {
		head = in[:total]
	} else {