}

// addrRanges is a data structure holding a collection of ranges of
// address space.
//
// The ranges are coalesced eagerly to reduce the
// number ranges it holds.
//
// The slice backing store for this field is persistentalloc'd
// and thus there is no way to free it.
//
// addrRanges is not thread-safe.
type addrRanges struct {
	// ranges is a slice of ranges sorted by base.

// leaked.
//
// This AddrRanges is mutable, so we can test methods like
// Add.
func NewAddrRanges() AddrRanges {
	r := addrRanges{}
	r.init(testSysStat)
	return AddrRanges{r, true}
}

// MakeAddrRanges creates a new addrRanges populated with
// the ranges in a.
//
// The returned AddrRanges is immutable, so methods like
// Add will fail.
func MakeAddrRanges(a ...AddrRange) AddrRanges {

	}
	if b := a.TotalBytes(); b != gotTotalBytes {
		t.Errorf("inconsistent total bytes: want %d, got %d", gotTotalBytes, b)
	}
	if t.Failed() {
		t.Errorf("addrRanges: %v", ranges)
		t.Fatal("detected bad addrRanges")
	}
}

func TestAddrRangesAdd(t *testing.T) {
	a := NewAddrRanges()

	// First range.
	a.Add(MakeAddrRange(512, 1024))
	validateAddrRanges(t, &a,
		MakeAddrRange(512, 1024),

	// and take additional measures to ensure that, so in nearly all
	// cases this should have just 1 element.
	//
	// All access is protected by the mheapLock.
	inUse addrRanges

	// scav stores the scavenger state.
	scav struct {
		// index is an efficient index of chunks that have pages available to
		// scavenge.
		index scavengeIndex