type SpanningTransformer interface {
	Transformer

	// Span returns a position in src such that transforming src[:n] results in
	// identical output src[:n] for these bytes. It does not necessarily return
	// the largest such n. The atEOF argument tells whether src represents the
	// last bytes of the input.
	//
	// Callers should always account for the n bytes consumed before
	// considering the error err.
	//

// total samples collected.
func (p *Profile) Merge(pb *Profile, r float64) error {
	if err := p.Compatible(pb); err != nil {
		return err
	}

	pb = pb.Copy()

	// Keep the largest of the two periods.
	if pb.Period > p.Period {
		p.Period = pb.Period
	}

	p.DurationNanos += pb.DurationNanos

	p.Mapping = append(p.Mapping, pb.Mapping...)
	for i, m := range p.Mapping {

	first := a
	lo := 0
	hi := b - a

	// Build heap with greatest element at top.
	for i := (hi - 1) / 2; i >= 0; i-- {
		siftDown_func(data, i, hi, first)
	}

	// Pop elements, largest first, into end of data.
	for i := hi - 1; i >= 0; i-- {
		data.Swap(first, first+i)
		siftDown_func(data, lo, i, first)
	}
}

// pdqsort_func sorts data[a:b].

func Offsetof(x ArbitraryType) uintptr

// Alignof takes an expression x of any type and returns the required alignment
// of a hypothetical variable v as if v was declared via var v = x.
// It is the largest value m such that the address of v is always zero mod m.
// It is the same as the value returned by [reflect.TypeOf](x).Align().
// As a special case, if a variable s is of struct type and f is a field

// Generates many inputs, builds and checks suffix arrays.
func test(t *testing.T, build func([]byte) []int) {
	t.Run("ababab...", func(t *testing.T) {
		// Very repetitive input has numLMS = len(x)/2-1
		// at top level, the largest it can be.
		// But maxID is only two (aba and ab$).
		size := 100000
		if testing.Short() {
			size = 10000
		}
		x := make([]byte, size)
		for i := range x {
			x[i] = "ab"[i%2]
		}

	first := a
	lo := 0
	hi := b - a

	// Build heap with greatest element at top.
	for i := (hi - 1) / 2; i >= 0; i-- {
		siftDownCmpFunc(data, i, hi, first, cmp)
	}

	// Pop elements, largest first, into end of data.
	for i := hi - 1; i >= 0; i-- {
		data[first], data[first+i] = data[first+i], data[first]
		siftDownCmpFunc(data, lo, i, first, cmp)
	}
}

// pdqsortCmpFunc sorts data[a:b].

</ul>

<h2>Garbage collection metrics</h2>
<ul>
<li><a href="/mmu">Minimum mutator utilization</a></li>
</ul>
<p>
  This chart indicates the maximum GC pause time (the largest x value
  for which y is zero), and more generally, the fraction of time that
  the processors are available to application goroutines ("mutators"),
  for any time window of a specified size, in the worst case.
</p>

	// prefers setCounts to be sorted for optimal behavior.
	if divisibleSize < setCounts[len(setCounts)-1] {
		return divisibleSize
	}

	// Figure out largest value of total_drives_in_erasure_set which results
	// in least number of total_drives/total_drives_erasure_set ratio.
	prevD := divisibleSize / setCounts[0]
	for _, cnt := range setCounts {
		if divisibleSize%cnt == 0 {

   * @since 20.0
   */
  public static BigInteger ceilingPowerOfTwo(BigInteger x) {
    return BigInteger.ZERO.setBit(log2(x, CEILING));
  }

  /**
   * Returns the largest power of two less than or equal to {@code x}. This is equivalent to {@code
   * BigInteger.valueOf(2).pow(log2(x, FLOOR))}.
   *
   * @throws IllegalArgumentException if {@code x <= 0}
   * @since 20.0
   */

      throw new ArithmeticException("ceilingPowerOfTwo(" + x + ") is not representable as a long");
    }
    return 1L << -Long.numberOfLeadingZeros(x - 1);
  }

  /**
   * Returns the largest power of two less than or equal to {@code x}. This is equivalent to {@code
   * checkedPow(2, log2(x, FLOOR))}.
   *
   * @throws IllegalArgumentException if {@code x <= 0}
   * @since 20.0
   */