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-rw-r--r--pkg/state/addr_set.go1643
1 files changed, 1643 insertions, 0 deletions
diff --git a/pkg/state/addr_set.go b/pkg/state/addr_set.go
new file mode 100644
index 000000000..591af5292
--- /dev/null
+++ b/pkg/state/addr_set.go
@@ -0,0 +1,1643 @@
+package state
+
+import (
+ "bytes"
+ "fmt"
+)
+
+// trackGaps is an optional parameter.
+//
+// If trackGaps is 1, the Set will track maximum gap size recursively,
+// enabling the GapIterator.{Prev,Next}LargeEnoughGap functions. In this
+// case, Key must be an unsigned integer.
+//
+// trackGaps must be 0 or 1.
+const addrtrackGaps = 0
+
+var _ = uint8(addrtrackGaps << 7) // Will fail if not zero or one.
+
+// dynamicGap is a type that disappears if trackGaps is 0.
+type addrdynamicGap [addrtrackGaps]uintptr
+
+// Get returns the value of the gap.
+//
+// Precondition: trackGaps must be non-zero.
+func (d *addrdynamicGap) Get() uintptr {
+ return d[:][0]
+}
+
+// Set sets the value of the gap.
+//
+// Precondition: trackGaps must be non-zero.
+func (d *addrdynamicGap) Set(v uintptr) {
+ d[:][0] = v
+}
+
+const (
+ // minDegree is the minimum degree of an internal node in a Set B-tree.
+ //
+ // - Any non-root node has at least minDegree-1 segments.
+ //
+ // - Any non-root internal (non-leaf) node has at least minDegree children.
+ //
+ // - The root node may have fewer than minDegree-1 segments, but it may
+ // only have 0 segments if the tree is empty.
+ //
+ // Our implementation requires minDegree >= 3. Higher values of minDegree
+ // usually improve performance, but increase memory usage for small sets.
+ addrminDegree = 10
+
+ addrmaxDegree = 2 * addrminDegree
+)
+
+// A Set is a mapping of segments with non-overlapping Range keys. The zero
+// value for a Set is an empty set. Set values are not safely movable nor
+// copyable. Set is thread-compatible.
+//
+// +stateify savable
+type addrSet struct {
+ root addrnode `state:".(*addrSegmentDataSlices)"`
+}
+
+// IsEmpty returns true if the set contains no segments.
+func (s *addrSet) IsEmpty() bool {
+ return s.root.nrSegments == 0
+}
+
+// IsEmptyRange returns true iff no segments in the set overlap the given
+// range. This is semantically equivalent to s.SpanRange(r) == 0, but may be
+// more efficient.
+func (s *addrSet) IsEmptyRange(r addrRange) bool {
+ switch {
+ case r.Length() < 0:
+ panic(fmt.Sprintf("invalid range %v", r))
+ case r.Length() == 0:
+ return true
+ }
+ _, gap := s.Find(r.Start)
+ if !gap.Ok() {
+ return false
+ }
+ return r.End <= gap.End()
+}
+
+// Span returns the total size of all segments in the set.
+func (s *addrSet) Span() uintptr {
+ var sz uintptr
+ for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() {
+ sz += seg.Range().Length()
+ }
+ return sz
+}
+
+// SpanRange returns the total size of the intersection of segments in the set
+// with the given range.
+func (s *addrSet) SpanRange(r addrRange) uintptr {
+ switch {
+ case r.Length() < 0:
+ panic(fmt.Sprintf("invalid range %v", r))
+ case r.Length() == 0:
+ return 0
+ }
+ var sz uintptr
+ for seg := s.LowerBoundSegment(r.Start); seg.Ok() && seg.Start() < r.End; seg = seg.NextSegment() {
+ sz += seg.Range().Intersect(r).Length()
+ }
+ return sz
+}
+
+// FirstSegment returns the first segment in the set. If the set is empty,
+// FirstSegment returns a terminal iterator.
+func (s *addrSet) FirstSegment() addrIterator {
+ if s.root.nrSegments == 0 {
+ return addrIterator{}
+ }
+ return s.root.firstSegment()
+}
+
+// LastSegment returns the last segment in the set. If the set is empty,
+// LastSegment returns a terminal iterator.
+func (s *addrSet) LastSegment() addrIterator {
+ if s.root.nrSegments == 0 {
+ return addrIterator{}
+ }
+ return s.root.lastSegment()
+}
+
+// FirstGap returns the first gap in the set.
+func (s *addrSet) FirstGap() addrGapIterator {
+ n := &s.root
+ for n.hasChildren {
+ n = n.children[0]
+ }
+ return addrGapIterator{n, 0}
+}
+
+// LastGap returns the last gap in the set.
+func (s *addrSet) LastGap() addrGapIterator {
+ n := &s.root
+ for n.hasChildren {
+ n = n.children[n.nrSegments]
+ }
+ return addrGapIterator{n, n.nrSegments}
+}
+
+// Find returns the segment or gap whose range contains the given key. If a
+// segment is found, the returned Iterator is non-terminal and the
+// returned GapIterator is terminal. Otherwise, the returned Iterator is
+// terminal and the returned GapIterator is non-terminal.
+func (s *addrSet) Find(key uintptr) (addrIterator, addrGapIterator) {
+ n := &s.root
+ for {
+
+ lower := 0
+ upper := n.nrSegments
+ for lower < upper {
+ i := lower + (upper-lower)/2
+ if r := n.keys[i]; key < r.End {
+ if key >= r.Start {
+ return addrIterator{n, i}, addrGapIterator{}
+ }
+ upper = i
+ } else {
+ lower = i + 1
+ }
+ }
+ i := lower
+ if !n.hasChildren {
+ return addrIterator{}, addrGapIterator{n, i}
+ }
+ n = n.children[i]
+ }
+}
+
+// FindSegment returns the segment whose range contains the given key. If no
+// such segment exists, FindSegment returns a terminal iterator.
+func (s *addrSet) FindSegment(key uintptr) addrIterator {
+ seg, _ := s.Find(key)
+ return seg
+}
+
+// LowerBoundSegment returns the segment with the lowest range that contains a
+// key greater than or equal to min. If no such segment exists,
+// LowerBoundSegment returns a terminal iterator.
+func (s *addrSet) LowerBoundSegment(min uintptr) addrIterator {
+ seg, gap := s.Find(min)
+ if seg.Ok() {
+ return seg
+ }
+ return gap.NextSegment()
+}
+
+// UpperBoundSegment returns the segment with the highest range that contains a
+// key less than or equal to max. If no such segment exists, UpperBoundSegment
+// returns a terminal iterator.
+func (s *addrSet) UpperBoundSegment(max uintptr) addrIterator {
+ seg, gap := s.Find(max)
+ if seg.Ok() {
+ return seg
+ }
+ return gap.PrevSegment()
+}
+
+// FindGap returns the gap containing the given key. If no such gap exists
+// (i.e. the set contains a segment containing that key), FindGap returns a
+// terminal iterator.
+func (s *addrSet) FindGap(key uintptr) addrGapIterator {
+ _, gap := s.Find(key)
+ return gap
+}
+
+// LowerBoundGap returns the gap with the lowest range that is greater than or
+// equal to min.
+func (s *addrSet) LowerBoundGap(min uintptr) addrGapIterator {
+ seg, gap := s.Find(min)
+ if gap.Ok() {
+ return gap
+ }
+ return seg.NextGap()
+}
+
+// UpperBoundGap returns the gap with the highest range that is less than or
+// equal to max.
+func (s *addrSet) UpperBoundGap(max uintptr) addrGapIterator {
+ seg, gap := s.Find(max)
+ if gap.Ok() {
+ return gap
+ }
+ return seg.PrevGap()
+}
+
+// Add inserts the given segment into the set and returns true. If the new
+// segment can be merged with adjacent segments, Add will do so. If the new
+// segment would overlap an existing segment, Add returns false. If Add
+// succeeds, all existing iterators are invalidated.
+func (s *addrSet) Add(r addrRange, val *objectEncodeState) bool {
+ if r.Length() <= 0 {
+ panic(fmt.Sprintf("invalid segment range %v", r))
+ }
+ gap := s.FindGap(r.Start)
+ if !gap.Ok() {
+ return false
+ }
+ if r.End > gap.End() {
+ return false
+ }
+ s.Insert(gap, r, val)
+ return true
+}
+
+// AddWithoutMerging inserts the given segment into the set and returns true.
+// If it would overlap an existing segment, AddWithoutMerging does nothing and
+// returns false. If AddWithoutMerging succeeds, all existing iterators are
+// invalidated.
+func (s *addrSet) AddWithoutMerging(r addrRange, val *objectEncodeState) bool {
+ if r.Length() <= 0 {
+ panic(fmt.Sprintf("invalid segment range %v", r))
+ }
+ gap := s.FindGap(r.Start)
+ if !gap.Ok() {
+ return false
+ }
+ if r.End > gap.End() {
+ return false
+ }
+ s.InsertWithoutMergingUnchecked(gap, r, val)
+ return true
+}
+
+// Insert inserts the given segment into the given gap. If the new segment can
+// be merged with adjacent segments, Insert will do so. Insert returns an
+// iterator to the segment containing the inserted value (which may have been
+// merged with other values). All existing iterators (including gap, but not
+// including the returned iterator) are invalidated.
+//
+// If the gap cannot accommodate the segment, or if r is invalid, Insert panics.
+//
+// Insert is semantically equivalent to a InsertWithoutMerging followed by a
+// Merge, but may be more efficient. Note that there is no unchecked variant of
+// Insert since Insert must retrieve and inspect gap's predecessor and
+// successor segments regardless.
+func (s *addrSet) Insert(gap addrGapIterator, r addrRange, val *objectEncodeState) addrIterator {
+ if r.Length() <= 0 {
+ panic(fmt.Sprintf("invalid segment range %v", r))
+ }
+ prev, next := gap.PrevSegment(), gap.NextSegment()
+ if prev.Ok() && prev.End() > r.Start {
+ panic(fmt.Sprintf("new segment %v overlaps predecessor %v", r, prev.Range()))
+ }
+ if next.Ok() && next.Start() < r.End {
+ panic(fmt.Sprintf("new segment %v overlaps successor %v", r, next.Range()))
+ }
+ if prev.Ok() && prev.End() == r.Start {
+ if mval, ok := (addrSetFunctions{}).Merge(prev.Range(), prev.Value(), r, val); ok {
+ shrinkMaxGap := addrtrackGaps != 0 && gap.Range().Length() == gap.node.maxGap.Get()
+ prev.SetEndUnchecked(r.End)
+ prev.SetValue(mval)
+ if shrinkMaxGap {
+ gap.node.updateMaxGapLeaf()
+ }
+ if next.Ok() && next.Start() == r.End {
+ val = mval
+ if mval, ok := (addrSetFunctions{}).Merge(prev.Range(), val, next.Range(), next.Value()); ok {
+ prev.SetEndUnchecked(next.End())
+ prev.SetValue(mval)
+ return s.Remove(next).PrevSegment()
+ }
+ }
+ return prev
+ }
+ }
+ if next.Ok() && next.Start() == r.End {
+ if mval, ok := (addrSetFunctions{}).Merge(r, val, next.Range(), next.Value()); ok {
+ shrinkMaxGap := addrtrackGaps != 0 && gap.Range().Length() == gap.node.maxGap.Get()
+ next.SetStartUnchecked(r.Start)
+ next.SetValue(mval)
+ if shrinkMaxGap {
+ gap.node.updateMaxGapLeaf()
+ }
+ return next
+ }
+ }
+
+ return s.InsertWithoutMergingUnchecked(gap, r, val)
+}
+
+// InsertWithoutMerging inserts the given segment into the given gap and
+// returns an iterator to the inserted segment. All existing iterators
+// (including gap, but not including the returned iterator) are invalidated.
+//
+// If the gap cannot accommodate the segment, or if r is invalid,
+// InsertWithoutMerging panics.
+func (s *addrSet) InsertWithoutMerging(gap addrGapIterator, r addrRange, val *objectEncodeState) addrIterator {
+ if r.Length() <= 0 {
+ panic(fmt.Sprintf("invalid segment range %v", r))
+ }
+ if gr := gap.Range(); !gr.IsSupersetOf(r) {
+ panic(fmt.Sprintf("cannot insert segment range %v into gap range %v", r, gr))
+ }
+ return s.InsertWithoutMergingUnchecked(gap, r, val)
+}
+
+// InsertWithoutMergingUnchecked inserts the given segment into the given gap
+// and returns an iterator to the inserted segment. All existing iterators
+// (including gap, but not including the returned iterator) are invalidated.
+//
+// Preconditions:
+// * r.Start >= gap.Start().
+// * r.End <= gap.End().
+func (s *addrSet) InsertWithoutMergingUnchecked(gap addrGapIterator, r addrRange, val *objectEncodeState) addrIterator {
+ gap = gap.node.rebalanceBeforeInsert(gap)
+ splitMaxGap := addrtrackGaps != 0 && (gap.node.nrSegments == 0 || gap.Range().Length() == gap.node.maxGap.Get())
+ copy(gap.node.keys[gap.index+1:], gap.node.keys[gap.index:gap.node.nrSegments])
+ copy(gap.node.values[gap.index+1:], gap.node.values[gap.index:gap.node.nrSegments])
+ gap.node.keys[gap.index] = r
+ gap.node.values[gap.index] = val
+ gap.node.nrSegments++
+ if splitMaxGap {
+ gap.node.updateMaxGapLeaf()
+ }
+ return addrIterator{gap.node, gap.index}
+}
+
+// Remove removes the given segment and returns an iterator to the vacated gap.
+// All existing iterators (including seg, but not including the returned
+// iterator) are invalidated.
+func (s *addrSet) Remove(seg addrIterator) addrGapIterator {
+
+ if seg.node.hasChildren {
+
+ victim := seg.PrevSegment()
+
+ seg.SetRangeUnchecked(victim.Range())
+ seg.SetValue(victim.Value())
+
+ nextAdjacentNode := seg.NextSegment().node
+ if addrtrackGaps != 0 {
+ nextAdjacentNode.updateMaxGapLeaf()
+ }
+ return s.Remove(victim).NextGap()
+ }
+ copy(seg.node.keys[seg.index:], seg.node.keys[seg.index+1:seg.node.nrSegments])
+ copy(seg.node.values[seg.index:], seg.node.values[seg.index+1:seg.node.nrSegments])
+ addrSetFunctions{}.ClearValue(&seg.node.values[seg.node.nrSegments-1])
+ seg.node.nrSegments--
+ if addrtrackGaps != 0 {
+ seg.node.updateMaxGapLeaf()
+ }
+ return seg.node.rebalanceAfterRemove(addrGapIterator{seg.node, seg.index})
+}
+
+// RemoveAll removes all segments from the set. All existing iterators are
+// invalidated.
+func (s *addrSet) RemoveAll() {
+ s.root = addrnode{}
+}
+
+// RemoveRange removes all segments in the given range. An iterator to the
+// newly formed gap is returned, and all existing iterators are invalidated.
+func (s *addrSet) RemoveRange(r addrRange) addrGapIterator {
+ seg, gap := s.Find(r.Start)
+ if seg.Ok() {
+ seg = s.Isolate(seg, r)
+ gap = s.Remove(seg)
+ }
+ for seg = gap.NextSegment(); seg.Ok() && seg.Start() < r.End; seg = gap.NextSegment() {
+ seg = s.Isolate(seg, r)
+ gap = s.Remove(seg)
+ }
+ return gap
+}
+
+// Merge attempts to merge two neighboring segments. If successful, Merge
+// returns an iterator to the merged segment, and all existing iterators are
+// invalidated. Otherwise, Merge returns a terminal iterator.
+//
+// If first is not the predecessor of second, Merge panics.
+func (s *addrSet) Merge(first, second addrIterator) addrIterator {
+ if first.NextSegment() != second {
+ panic(fmt.Sprintf("attempt to merge non-neighboring segments %v, %v", first.Range(), second.Range()))
+ }
+ return s.MergeUnchecked(first, second)
+}
+
+// MergeUnchecked attempts to merge two neighboring segments. If successful,
+// MergeUnchecked returns an iterator to the merged segment, and all existing
+// iterators are invalidated. Otherwise, MergeUnchecked returns a terminal
+// iterator.
+//
+// Precondition: first is the predecessor of second: first.NextSegment() ==
+// second, first == second.PrevSegment().
+func (s *addrSet) MergeUnchecked(first, second addrIterator) addrIterator {
+ if first.End() == second.Start() {
+ if mval, ok := (addrSetFunctions{}).Merge(first.Range(), first.Value(), second.Range(), second.Value()); ok {
+
+ first.SetEndUnchecked(second.End())
+ first.SetValue(mval)
+
+ return s.Remove(second).PrevSegment()
+ }
+ }
+ return addrIterator{}
+}
+
+// MergeAll attempts to merge all adjacent segments in the set. All existing
+// iterators are invalidated.
+func (s *addrSet) MergeAll() {
+ seg := s.FirstSegment()
+ if !seg.Ok() {
+ return
+ }
+ next := seg.NextSegment()
+ for next.Ok() {
+ if mseg := s.MergeUnchecked(seg, next); mseg.Ok() {
+ seg, next = mseg, mseg.NextSegment()
+ } else {
+ seg, next = next, next.NextSegment()
+ }
+ }
+}
+
+// MergeRange attempts to merge all adjacent segments that contain a key in the
+// specific range. All existing iterators are invalidated.
+func (s *addrSet) MergeRange(r addrRange) {
+ seg := s.LowerBoundSegment(r.Start)
+ if !seg.Ok() {
+ return
+ }
+ next := seg.NextSegment()
+ for next.Ok() && next.Range().Start < r.End {
+ if mseg := s.MergeUnchecked(seg, next); mseg.Ok() {
+ seg, next = mseg, mseg.NextSegment()
+ } else {
+ seg, next = next, next.NextSegment()
+ }
+ }
+}
+
+// MergeAdjacent attempts to merge the segment containing r.Start with its
+// predecessor, and the segment containing r.End-1 with its successor.
+func (s *addrSet) MergeAdjacent(r addrRange) {
+ first := s.FindSegment(r.Start)
+ if first.Ok() {
+ if prev := first.PrevSegment(); prev.Ok() {
+ s.Merge(prev, first)
+ }
+ }
+ last := s.FindSegment(r.End - 1)
+ if last.Ok() {
+ if next := last.NextSegment(); next.Ok() {
+ s.Merge(last, next)
+ }
+ }
+}
+
+// Split splits the given segment at the given key and returns iterators to the
+// two resulting segments. All existing iterators (including seg, but not
+// including the returned iterators) are invalidated.
+//
+// If the segment cannot be split at split (because split is at the start or
+// end of the segment's range, so splitting would produce a segment with zero
+// length, or because split falls outside the segment's range altogether),
+// Split panics.
+func (s *addrSet) Split(seg addrIterator, split uintptr) (addrIterator, addrIterator) {
+ if !seg.Range().CanSplitAt(split) {
+ panic(fmt.Sprintf("can't split %v at %v", seg.Range(), split))
+ }
+ return s.SplitUnchecked(seg, split)
+}
+
+// SplitUnchecked splits the given segment at the given key and returns
+// iterators to the two resulting segments. All existing iterators (including
+// seg, but not including the returned iterators) are invalidated.
+//
+// Preconditions: seg.Start() < key < seg.End().
+func (s *addrSet) SplitUnchecked(seg addrIterator, split uintptr) (addrIterator, addrIterator) {
+ val1, val2 := (addrSetFunctions{}).Split(seg.Range(), seg.Value(), split)
+ end2 := seg.End()
+ seg.SetEndUnchecked(split)
+ seg.SetValue(val1)
+ seg2 := s.InsertWithoutMergingUnchecked(seg.NextGap(), addrRange{split, end2}, val2)
+
+ return seg2.PrevSegment(), seg2
+}
+
+// SplitAt splits the segment straddling split, if one exists. SplitAt returns
+// true if a segment was split and false otherwise. If SplitAt splits a
+// segment, all existing iterators are invalidated.
+func (s *addrSet) SplitAt(split uintptr) bool {
+ if seg := s.FindSegment(split); seg.Ok() && seg.Range().CanSplitAt(split) {
+ s.SplitUnchecked(seg, split)
+ return true
+ }
+ return false
+}
+
+// Isolate ensures that the given segment's range does not escape r by
+// splitting at r.Start and r.End if necessary, and returns an updated iterator
+// to the bounded segment. All existing iterators (including seg, but not
+// including the returned iterators) are invalidated.
+func (s *addrSet) Isolate(seg addrIterator, r addrRange) addrIterator {
+ if seg.Range().CanSplitAt(r.Start) {
+ _, seg = s.SplitUnchecked(seg, r.Start)
+ }
+ if seg.Range().CanSplitAt(r.End) {
+ seg, _ = s.SplitUnchecked(seg, r.End)
+ }
+ return seg
+}
+
+// ApplyContiguous applies a function to a contiguous range of segments,
+// splitting if necessary. The function is applied until the first gap is
+// encountered, at which point the gap is returned. If the function is applied
+// across the entire range, a terminal gap is returned. All existing iterators
+// are invalidated.
+//
+// N.B. The Iterator must not be invalidated by the function.
+func (s *addrSet) ApplyContiguous(r addrRange, fn func(seg addrIterator)) addrGapIterator {
+ seg, gap := s.Find(r.Start)
+ if !seg.Ok() {
+ return gap
+ }
+ for {
+ seg = s.Isolate(seg, r)
+ fn(seg)
+ if seg.End() >= r.End {
+ return addrGapIterator{}
+ }
+ gap = seg.NextGap()
+ if !gap.IsEmpty() {
+ return gap
+ }
+ seg = gap.NextSegment()
+ if !seg.Ok() {
+
+ return addrGapIterator{}
+ }
+ }
+}
+
+// +stateify savable
+type addrnode struct {
+ // An internal binary tree node looks like:
+ //
+ // K
+ // / \
+ // Cl Cr
+ //
+ // where all keys in the subtree rooted by Cl (the left subtree) are less
+ // than K (the key of the parent node), and all keys in the subtree rooted
+ // by Cr (the right subtree) are greater than K.
+ //
+ // An internal B-tree node's indexes work out to look like:
+ //
+ // K0 K1 K2 ... Kn-1
+ // / \/ \/ \ ... / \
+ // C0 C1 C2 C3 ... Cn-1 Cn
+ //
+ // where n is nrSegments.
+ nrSegments int
+
+ // parent is a pointer to this node's parent. If this node is root, parent
+ // is nil.
+ parent *addrnode
+
+ // parentIndex is the index of this node in parent.children.
+ parentIndex int
+
+ // Flag for internal nodes that is technically redundant with "children[0]
+ // != nil", but is stored in the first cache line. "hasChildren" rather
+ // than "isLeaf" because false must be the correct value for an empty root.
+ hasChildren bool
+
+ // The longest gap within this node. If the node is a leaf, it's simply the
+ // maximum gap among all the (nrSegments+1) gaps formed by its nrSegments keys
+ // including the 0th and nrSegments-th gap possibly shared with its upper-level
+ // nodes; if it's a non-leaf node, it's the max of all children's maxGap.
+ maxGap addrdynamicGap
+
+ // Nodes store keys and values in separate arrays to maximize locality in
+ // the common case (scanning keys for lookup).
+ keys [addrmaxDegree - 1]addrRange
+ values [addrmaxDegree - 1]*objectEncodeState
+ children [addrmaxDegree]*addrnode
+}
+
+// firstSegment returns the first segment in the subtree rooted by n.
+//
+// Preconditions: n.nrSegments != 0.
+func (n *addrnode) firstSegment() addrIterator {
+ for n.hasChildren {
+ n = n.children[0]
+ }
+ return addrIterator{n, 0}
+}
+
+// lastSegment returns the last segment in the subtree rooted by n.
+//
+// Preconditions: n.nrSegments != 0.
+func (n *addrnode) lastSegment() addrIterator {
+ for n.hasChildren {
+ n = n.children[n.nrSegments]
+ }
+ return addrIterator{n, n.nrSegments - 1}
+}
+
+func (n *addrnode) prevSibling() *addrnode {
+ if n.parent == nil || n.parentIndex == 0 {
+ return nil
+ }
+ return n.parent.children[n.parentIndex-1]
+}
+
+func (n *addrnode) nextSibling() *addrnode {
+ if n.parent == nil || n.parentIndex == n.parent.nrSegments {
+ return nil
+ }
+ return n.parent.children[n.parentIndex+1]
+}
+
+// rebalanceBeforeInsert splits n and its ancestors if they are full, as
+// required for insertion, and returns an updated iterator to the position
+// represented by gap.
+func (n *addrnode) rebalanceBeforeInsert(gap addrGapIterator) addrGapIterator {
+ if n.nrSegments < addrmaxDegree-1 {
+ return gap
+ }
+ if n.parent != nil {
+ gap = n.parent.rebalanceBeforeInsert(gap)
+ }
+ if n.parent == nil {
+
+ left := &addrnode{
+ nrSegments: addrminDegree - 1,
+ parent: n,
+ parentIndex: 0,
+ hasChildren: n.hasChildren,
+ }
+ right := &addrnode{
+ nrSegments: addrminDegree - 1,
+ parent: n,
+ parentIndex: 1,
+ hasChildren: n.hasChildren,
+ }
+ copy(left.keys[:addrminDegree-1], n.keys[:addrminDegree-1])
+ copy(left.values[:addrminDegree-1], n.values[:addrminDegree-1])
+ copy(right.keys[:addrminDegree-1], n.keys[addrminDegree:])
+ copy(right.values[:addrminDegree-1], n.values[addrminDegree:])
+ n.keys[0], n.values[0] = n.keys[addrminDegree-1], n.values[addrminDegree-1]
+ addrzeroValueSlice(n.values[1:])
+ if n.hasChildren {
+ copy(left.children[:addrminDegree], n.children[:addrminDegree])
+ copy(right.children[:addrminDegree], n.children[addrminDegree:])
+ addrzeroNodeSlice(n.children[2:])
+ for i := 0; i < addrminDegree; i++ {
+ left.children[i].parent = left
+ left.children[i].parentIndex = i
+ right.children[i].parent = right
+ right.children[i].parentIndex = i
+ }
+ }
+ n.nrSegments = 1
+ n.hasChildren = true
+ n.children[0] = left
+ n.children[1] = right
+
+ if addrtrackGaps != 0 {
+ left.updateMaxGapLocal()
+ right.updateMaxGapLocal()
+ }
+ if gap.node != n {
+ return gap
+ }
+ if gap.index < addrminDegree {
+ return addrGapIterator{left, gap.index}
+ }
+ return addrGapIterator{right, gap.index - addrminDegree}
+ }
+
+ copy(n.parent.keys[n.parentIndex+1:], n.parent.keys[n.parentIndex:n.parent.nrSegments])
+ copy(n.parent.values[n.parentIndex+1:], n.parent.values[n.parentIndex:n.parent.nrSegments])
+ n.parent.keys[n.parentIndex], n.parent.values[n.parentIndex] = n.keys[addrminDegree-1], n.values[addrminDegree-1]
+ copy(n.parent.children[n.parentIndex+2:], n.parent.children[n.parentIndex+1:n.parent.nrSegments+1])
+ for i := n.parentIndex + 2; i < n.parent.nrSegments+2; i++ {
+ n.parent.children[i].parentIndex = i
+ }
+ sibling := &addrnode{
+ nrSegments: addrminDegree - 1,
+ parent: n.parent,
+ parentIndex: n.parentIndex + 1,
+ hasChildren: n.hasChildren,
+ }
+ n.parent.children[n.parentIndex+1] = sibling
+ n.parent.nrSegments++
+ copy(sibling.keys[:addrminDegree-1], n.keys[addrminDegree:])
+ copy(sibling.values[:addrminDegree-1], n.values[addrminDegree:])
+ addrzeroValueSlice(n.values[addrminDegree-1:])
+ if n.hasChildren {
+ copy(sibling.children[:addrminDegree], n.children[addrminDegree:])
+ addrzeroNodeSlice(n.children[addrminDegree:])
+ for i := 0; i < addrminDegree; i++ {
+ sibling.children[i].parent = sibling
+ sibling.children[i].parentIndex = i
+ }
+ }
+ n.nrSegments = addrminDegree - 1
+
+ if addrtrackGaps != 0 {
+ n.updateMaxGapLocal()
+ sibling.updateMaxGapLocal()
+ }
+
+ if gap.node != n {
+ return gap
+ }
+ if gap.index < addrminDegree {
+ return gap
+ }
+ return addrGapIterator{sibling, gap.index - addrminDegree}
+}
+
+// rebalanceAfterRemove "unsplits" n and its ancestors if they are deficient
+// (contain fewer segments than required by B-tree invariants), as required for
+// removal, and returns an updated iterator to the position represented by gap.
+//
+// Precondition: n is the only node in the tree that may currently violate a
+// B-tree invariant.
+func (n *addrnode) rebalanceAfterRemove(gap addrGapIterator) addrGapIterator {
+ for {
+ if n.nrSegments >= addrminDegree-1 {
+ return gap
+ }
+ if n.parent == nil {
+
+ return gap
+ }
+
+ if sibling := n.prevSibling(); sibling != nil && sibling.nrSegments >= addrminDegree {
+ copy(n.keys[1:], n.keys[:n.nrSegments])
+ copy(n.values[1:], n.values[:n.nrSegments])
+ n.keys[0] = n.parent.keys[n.parentIndex-1]
+ n.values[0] = n.parent.values[n.parentIndex-1]
+ n.parent.keys[n.parentIndex-1] = sibling.keys[sibling.nrSegments-1]
+ n.parent.values[n.parentIndex-1] = sibling.values[sibling.nrSegments-1]
+ addrSetFunctions{}.ClearValue(&sibling.values[sibling.nrSegments-1])
+ if n.hasChildren {
+ copy(n.children[1:], n.children[:n.nrSegments+1])
+ n.children[0] = sibling.children[sibling.nrSegments]
+ sibling.children[sibling.nrSegments] = nil
+ n.children[0].parent = n
+ n.children[0].parentIndex = 0
+ for i := 1; i < n.nrSegments+2; i++ {
+ n.children[i].parentIndex = i
+ }
+ }
+ n.nrSegments++
+ sibling.nrSegments--
+
+ if addrtrackGaps != 0 {
+ n.updateMaxGapLocal()
+ sibling.updateMaxGapLocal()
+ }
+ if gap.node == sibling && gap.index == sibling.nrSegments {
+ return addrGapIterator{n, 0}
+ }
+ if gap.node == n {
+ return addrGapIterator{n, gap.index + 1}
+ }
+ return gap
+ }
+ if sibling := n.nextSibling(); sibling != nil && sibling.nrSegments >= addrminDegree {
+ n.keys[n.nrSegments] = n.parent.keys[n.parentIndex]
+ n.values[n.nrSegments] = n.parent.values[n.parentIndex]
+ n.parent.keys[n.parentIndex] = sibling.keys[0]
+ n.parent.values[n.parentIndex] = sibling.values[0]
+ copy(sibling.keys[:sibling.nrSegments-1], sibling.keys[1:])
+ copy(sibling.values[:sibling.nrSegments-1], sibling.values[1:])
+ addrSetFunctions{}.ClearValue(&sibling.values[sibling.nrSegments-1])
+ if n.hasChildren {
+ n.children[n.nrSegments+1] = sibling.children[0]
+ copy(sibling.children[:sibling.nrSegments], sibling.children[1:])
+ sibling.children[sibling.nrSegments] = nil
+ n.children[n.nrSegments+1].parent = n
+ n.children[n.nrSegments+1].parentIndex = n.nrSegments + 1
+ for i := 0; i < sibling.nrSegments; i++ {
+ sibling.children[i].parentIndex = i
+ }
+ }
+ n.nrSegments++
+ sibling.nrSegments--
+
+ if addrtrackGaps != 0 {
+ n.updateMaxGapLocal()
+ sibling.updateMaxGapLocal()
+ }
+ if gap.node == sibling {
+ if gap.index == 0 {
+ return addrGapIterator{n, n.nrSegments}
+ }
+ return addrGapIterator{sibling, gap.index - 1}
+ }
+ return gap
+ }
+
+ p := n.parent
+ if p.nrSegments == 1 {
+
+ left, right := p.children[0], p.children[1]
+ p.nrSegments = left.nrSegments + right.nrSegments + 1
+ p.hasChildren = left.hasChildren
+ p.keys[left.nrSegments] = p.keys[0]
+ p.values[left.nrSegments] = p.values[0]
+ copy(p.keys[:left.nrSegments], left.keys[:left.nrSegments])
+ copy(p.values[:left.nrSegments], left.values[:left.nrSegments])
+ copy(p.keys[left.nrSegments+1:], right.keys[:right.nrSegments])
+ copy(p.values[left.nrSegments+1:], right.values[:right.nrSegments])
+ if left.hasChildren {
+ copy(p.children[:left.nrSegments+1], left.children[:left.nrSegments+1])
+ copy(p.children[left.nrSegments+1:], right.children[:right.nrSegments+1])
+ for i := 0; i < p.nrSegments+1; i++ {
+ p.children[i].parent = p
+ p.children[i].parentIndex = i
+ }
+ } else {
+ p.children[0] = nil
+ p.children[1] = nil
+ }
+
+ if gap.node == left {
+ return addrGapIterator{p, gap.index}
+ }
+ if gap.node == right {
+ return addrGapIterator{p, gap.index + left.nrSegments + 1}
+ }
+ return gap
+ }
+ // Merge n and either sibling, along with the segment separating the
+ // two, into whichever of the two nodes comes first. This is the
+ // reverse of the non-root splitting case in
+ // node.rebalanceBeforeInsert.
+ var left, right *addrnode
+ if n.parentIndex > 0 {
+ left = n.prevSibling()
+ right = n
+ } else {
+ left = n
+ right = n.nextSibling()
+ }
+
+ if gap.node == right {
+ gap = addrGapIterator{left, gap.index + left.nrSegments + 1}
+ }
+ left.keys[left.nrSegments] = p.keys[left.parentIndex]
+ left.values[left.nrSegments] = p.values[left.parentIndex]
+ copy(left.keys[left.nrSegments+1:], right.keys[:right.nrSegments])
+ copy(left.values[left.nrSegments+1:], right.values[:right.nrSegments])
+ if left.hasChildren {
+ copy(left.children[left.nrSegments+1:], right.children[:right.nrSegments+1])
+ for i := left.nrSegments + 1; i < left.nrSegments+right.nrSegments+2; i++ {
+ left.children[i].parent = left
+ left.children[i].parentIndex = i
+ }
+ }
+ left.nrSegments += right.nrSegments + 1
+ copy(p.keys[left.parentIndex:], p.keys[left.parentIndex+1:p.nrSegments])
+ copy(p.values[left.parentIndex:], p.values[left.parentIndex+1:p.nrSegments])
+ addrSetFunctions{}.ClearValue(&p.values[p.nrSegments-1])
+ copy(p.children[left.parentIndex+1:], p.children[left.parentIndex+2:p.nrSegments+1])
+ for i := 0; i < p.nrSegments; i++ {
+ p.children[i].parentIndex = i
+ }
+ p.children[p.nrSegments] = nil
+ p.nrSegments--
+
+ if addrtrackGaps != 0 {
+ left.updateMaxGapLocal()
+ }
+
+ n = p
+ }
+}
+
+// updateMaxGapLeaf updates maxGap bottom-up from the calling leaf until no
+// necessary update.
+//
+// Preconditions: n must be a leaf node, trackGaps must be 1.
+func (n *addrnode) updateMaxGapLeaf() {
+ if n.hasChildren {
+ panic(fmt.Sprintf("updateMaxGapLeaf should always be called on leaf node: %v", n))
+ }
+ max := n.calculateMaxGapLeaf()
+ if max == n.maxGap.Get() {
+
+ return
+ }
+ oldMax := n.maxGap.Get()
+ n.maxGap.Set(max)
+ if max > oldMax {
+
+ for p := n.parent; p != nil; p = p.parent {
+ if p.maxGap.Get() >= max {
+
+ break
+ }
+
+ p.maxGap.Set(max)
+ }
+ return
+ }
+
+ for p := n.parent; p != nil; p = p.parent {
+ if p.maxGap.Get() > oldMax {
+
+ break
+ }
+
+ parentNewMax := p.calculateMaxGapInternal()
+ if p.maxGap.Get() == parentNewMax {
+
+ break
+ }
+
+ p.maxGap.Set(parentNewMax)
+ }
+}
+
+// updateMaxGapLocal updates maxGap of the calling node solely with no
+// propagation to ancestor nodes.
+//
+// Precondition: trackGaps must be 1.
+func (n *addrnode) updateMaxGapLocal() {
+ if !n.hasChildren {
+
+ n.maxGap.Set(n.calculateMaxGapLeaf())
+ } else {
+
+ n.maxGap.Set(n.calculateMaxGapInternal())
+ }
+}
+
+// calculateMaxGapLeaf iterates the gaps within a leaf node and calculate the
+// max.
+//
+// Preconditions: n must be a leaf node.
+func (n *addrnode) calculateMaxGapLeaf() uintptr {
+ max := addrGapIterator{n, 0}.Range().Length()
+ for i := 1; i <= n.nrSegments; i++ {
+ if current := (addrGapIterator{n, i}).Range().Length(); current > max {
+ max = current
+ }
+ }
+ return max
+}
+
+// calculateMaxGapInternal iterates children's maxGap within an internal node n
+// and calculate the max.
+//
+// Preconditions: n must be a non-leaf node.
+func (n *addrnode) calculateMaxGapInternal() uintptr {
+ max := n.children[0].maxGap.Get()
+ for i := 1; i <= n.nrSegments; i++ {
+ if current := n.children[i].maxGap.Get(); current > max {
+ max = current
+ }
+ }
+ return max
+}
+
+// searchFirstLargeEnoughGap returns the first gap having at least minSize length
+// in the subtree rooted by n. If not found, return a terminal gap iterator.
+func (n *addrnode) searchFirstLargeEnoughGap(minSize uintptr) addrGapIterator {
+ if n.maxGap.Get() < minSize {
+ return addrGapIterator{}
+ }
+ if n.hasChildren {
+ for i := 0; i <= n.nrSegments; i++ {
+ if largeEnoughGap := n.children[i].searchFirstLargeEnoughGap(minSize); largeEnoughGap.Ok() {
+ return largeEnoughGap
+ }
+ }
+ } else {
+ for i := 0; i <= n.nrSegments; i++ {
+ currentGap := addrGapIterator{n, i}
+ if currentGap.Range().Length() >= minSize {
+ return currentGap
+ }
+ }
+ }
+ panic(fmt.Sprintf("invalid maxGap in %v", n))
+}
+
+// searchLastLargeEnoughGap returns the last gap having at least minSize length
+// in the subtree rooted by n. If not found, return a terminal gap iterator.
+func (n *addrnode) searchLastLargeEnoughGap(minSize uintptr) addrGapIterator {
+ if n.maxGap.Get() < minSize {
+ return addrGapIterator{}
+ }
+ if n.hasChildren {
+ for i := n.nrSegments; i >= 0; i-- {
+ if largeEnoughGap := n.children[i].searchLastLargeEnoughGap(minSize); largeEnoughGap.Ok() {
+ return largeEnoughGap
+ }
+ }
+ } else {
+ for i := n.nrSegments; i >= 0; i-- {
+ currentGap := addrGapIterator{n, i}
+ if currentGap.Range().Length() >= minSize {
+ return currentGap
+ }
+ }
+ }
+ panic(fmt.Sprintf("invalid maxGap in %v", n))
+}
+
+// A Iterator is conceptually one of:
+//
+// - A pointer to a segment in a set; or
+//
+// - A terminal iterator, which is a sentinel indicating that the end of
+// iteration has been reached.
+//
+// Iterators are copyable values and are meaningfully equality-comparable. The
+// zero value of Iterator is a terminal iterator.
+//
+// Unless otherwise specified, any mutation of a set invalidates all existing
+// iterators into the set.
+type addrIterator struct {
+ // node is the node containing the iterated segment. If the iterator is
+ // terminal, node is nil.
+ node *addrnode
+
+ // index is the index of the segment in node.keys/values.
+ index int
+}
+
+// Ok returns true if the iterator is not terminal. All other methods are only
+// valid for non-terminal iterators.
+func (seg addrIterator) Ok() bool {
+ return seg.node != nil
+}
+
+// Range returns the iterated segment's range key.
+func (seg addrIterator) Range() addrRange {
+ return seg.node.keys[seg.index]
+}
+
+// Start is equivalent to Range().Start, but should be preferred if only the
+// start of the range is needed.
+func (seg addrIterator) Start() uintptr {
+ return seg.node.keys[seg.index].Start
+}
+
+// End is equivalent to Range().End, but should be preferred if only the end of
+// the range is needed.
+func (seg addrIterator) End() uintptr {
+ return seg.node.keys[seg.index].End
+}
+
+// SetRangeUnchecked mutates the iterated segment's range key. This operation
+// does not invalidate any iterators.
+//
+// Preconditions:
+// * r.Length() > 0.
+// * The new range must not overlap an existing one:
+// * If seg.NextSegment().Ok(), then r.end <= seg.NextSegment().Start().
+// * If seg.PrevSegment().Ok(), then r.start >= seg.PrevSegment().End().
+func (seg addrIterator) SetRangeUnchecked(r addrRange) {
+ seg.node.keys[seg.index] = r
+}
+
+// SetRange mutates the iterated segment's range key. If the new range would
+// cause the iterated segment to overlap another segment, or if the new range
+// is invalid, SetRange panics. This operation does not invalidate any
+// iterators.
+func (seg addrIterator) SetRange(r addrRange) {
+ if r.Length() <= 0 {
+ panic(fmt.Sprintf("invalid segment range %v", r))
+ }
+ if prev := seg.PrevSegment(); prev.Ok() && r.Start < prev.End() {
+ panic(fmt.Sprintf("new segment range %v overlaps segment range %v", r, prev.Range()))
+ }
+ if next := seg.NextSegment(); next.Ok() && r.End > next.Start() {
+ panic(fmt.Sprintf("new segment range %v overlaps segment range %v", r, next.Range()))
+ }
+ seg.SetRangeUnchecked(r)
+}
+
+// SetStartUnchecked mutates the iterated segment's start. This operation does
+// not invalidate any iterators.
+//
+// Preconditions: The new start must be valid:
+// * start < seg.End()
+// * If seg.PrevSegment().Ok(), then start >= seg.PrevSegment().End().
+func (seg addrIterator) SetStartUnchecked(start uintptr) {
+ seg.node.keys[seg.index].Start = start
+}
+
+// SetStart mutates the iterated segment's start. If the new start value would
+// cause the iterated segment to overlap another segment, or would result in an
+// invalid range, SetStart panics. This operation does not invalidate any
+// iterators.
+func (seg addrIterator) SetStart(start uintptr) {
+ if start >= seg.End() {
+ panic(fmt.Sprintf("new start %v would invalidate segment range %v", start, seg.Range()))
+ }
+ if prev := seg.PrevSegment(); prev.Ok() && start < prev.End() {
+ panic(fmt.Sprintf("new start %v would cause segment range %v to overlap segment range %v", start, seg.Range(), prev.Range()))
+ }
+ seg.SetStartUnchecked(start)
+}
+
+// SetEndUnchecked mutates the iterated segment's end. This operation does not
+// invalidate any iterators.
+//
+// Preconditions: The new end must be valid:
+// * end > seg.Start().
+// * If seg.NextSegment().Ok(), then end <= seg.NextSegment().Start().
+func (seg addrIterator) SetEndUnchecked(end uintptr) {
+ seg.node.keys[seg.index].End = end
+}
+
+// SetEnd mutates the iterated segment's end. If the new end value would cause
+// the iterated segment to overlap another segment, or would result in an
+// invalid range, SetEnd panics. This operation does not invalidate any
+// iterators.
+func (seg addrIterator) SetEnd(end uintptr) {
+ if end <= seg.Start() {
+ panic(fmt.Sprintf("new end %v would invalidate segment range %v", end, seg.Range()))
+ }
+ if next := seg.NextSegment(); next.Ok() && end > next.Start() {
+ panic(fmt.Sprintf("new end %v would cause segment range %v to overlap segment range %v", end, seg.Range(), next.Range()))
+ }
+ seg.SetEndUnchecked(end)
+}
+
+// Value returns a copy of the iterated segment's value.
+func (seg addrIterator) Value() *objectEncodeState {
+ return seg.node.values[seg.index]
+}
+
+// ValuePtr returns a pointer to the iterated segment's value. The pointer is
+// invalidated if the iterator is invalidated. This operation does not
+// invalidate any iterators.
+func (seg addrIterator) ValuePtr() **objectEncodeState {
+ return &seg.node.values[seg.index]
+}
+
+// SetValue mutates the iterated segment's value. This operation does not
+// invalidate any iterators.
+func (seg addrIterator) SetValue(val *objectEncodeState) {
+ seg.node.values[seg.index] = val
+}
+
+// PrevSegment returns the iterated segment's predecessor. If there is no
+// preceding segment, PrevSegment returns a terminal iterator.
+func (seg addrIterator) PrevSegment() addrIterator {
+ if seg.node.hasChildren {
+ return seg.node.children[seg.index].lastSegment()
+ }
+ if seg.index > 0 {
+ return addrIterator{seg.node, seg.index - 1}
+ }
+ if seg.node.parent == nil {
+ return addrIterator{}
+ }
+ return addrsegmentBeforePosition(seg.node.parent, seg.node.parentIndex)
+}
+
+// NextSegment returns the iterated segment's successor. If there is no
+// succeeding segment, NextSegment returns a terminal iterator.
+func (seg addrIterator) NextSegment() addrIterator {
+ if seg.node.hasChildren {
+ return seg.node.children[seg.index+1].firstSegment()
+ }
+ if seg.index < seg.node.nrSegments-1 {
+ return addrIterator{seg.node, seg.index + 1}
+ }
+ if seg.node.parent == nil {
+ return addrIterator{}
+ }
+ return addrsegmentAfterPosition(seg.node.parent, seg.node.parentIndex)
+}
+
+// PrevGap returns the gap immediately before the iterated segment.
+func (seg addrIterator) PrevGap() addrGapIterator {
+ if seg.node.hasChildren {
+
+ return seg.node.children[seg.index].lastSegment().NextGap()
+ }
+ return addrGapIterator{seg.node, seg.index}
+}
+
+// NextGap returns the gap immediately after the iterated segment.
+func (seg addrIterator) NextGap() addrGapIterator {
+ if seg.node.hasChildren {
+ return seg.node.children[seg.index+1].firstSegment().PrevGap()
+ }
+ return addrGapIterator{seg.node, seg.index + 1}
+}
+
+// PrevNonEmpty returns the iterated segment's predecessor if it is adjacent,
+// or the gap before the iterated segment otherwise. If seg.Start() ==
+// Functions.MinKey(), PrevNonEmpty will return two terminal iterators.
+// Otherwise, exactly one of the iterators returned by PrevNonEmpty will be
+// non-terminal.
+func (seg addrIterator) PrevNonEmpty() (addrIterator, addrGapIterator) {
+ gap := seg.PrevGap()
+ if gap.Range().Length() != 0 {
+ return addrIterator{}, gap
+ }
+ return gap.PrevSegment(), addrGapIterator{}
+}
+
+// NextNonEmpty returns the iterated segment's successor if it is adjacent, or
+// the gap after the iterated segment otherwise. If seg.End() ==
+// Functions.MaxKey(), NextNonEmpty will return two terminal iterators.
+// Otherwise, exactly one of the iterators returned by NextNonEmpty will be
+// non-terminal.
+func (seg addrIterator) NextNonEmpty() (addrIterator, addrGapIterator) {
+ gap := seg.NextGap()
+ if gap.Range().Length() != 0 {
+ return addrIterator{}, gap
+ }
+ return gap.NextSegment(), addrGapIterator{}
+}
+
+// A GapIterator is conceptually one of:
+//
+// - A pointer to a position between two segments, before the first segment, or
+// after the last segment in a set, called a *gap*; or
+//
+// - A terminal iterator, which is a sentinel indicating that the end of
+// iteration has been reached.
+//
+// Note that the gap between two adjacent segments exists (iterators to it are
+// non-terminal), but has a length of zero. GapIterator.IsEmpty returns true
+// for such gaps. An empty set contains a single gap, spanning the entire range
+// of the set's keys.
+//
+// GapIterators are copyable values and are meaningfully equality-comparable.
+// The zero value of GapIterator is a terminal iterator.
+//
+// Unless otherwise specified, any mutation of a set invalidates all existing
+// iterators into the set.
+type addrGapIterator struct {
+ // The representation of a GapIterator is identical to that of an Iterator,
+ // except that index corresponds to positions between segments in the same
+ // way as for node.children (see comment for node.nrSegments).
+ node *addrnode
+ index int
+}
+
+// Ok returns true if the iterator is not terminal. All other methods are only
+// valid for non-terminal iterators.
+func (gap addrGapIterator) Ok() bool {
+ return gap.node != nil
+}
+
+// Range returns the range spanned by the iterated gap.
+func (gap addrGapIterator) Range() addrRange {
+ return addrRange{gap.Start(), gap.End()}
+}
+
+// Start is equivalent to Range().Start, but should be preferred if only the
+// start of the range is needed.
+func (gap addrGapIterator) Start() uintptr {
+ if ps := gap.PrevSegment(); ps.Ok() {
+ return ps.End()
+ }
+ return addrSetFunctions{}.MinKey()
+}
+
+// End is equivalent to Range().End, but should be preferred if only the end of
+// the range is needed.
+func (gap addrGapIterator) End() uintptr {
+ if ns := gap.NextSegment(); ns.Ok() {
+ return ns.Start()
+ }
+ return addrSetFunctions{}.MaxKey()
+}
+
+// IsEmpty returns true if the iterated gap is empty (that is, the "gap" is
+// between two adjacent segments.)
+func (gap addrGapIterator) IsEmpty() bool {
+ return gap.Range().Length() == 0
+}
+
+// PrevSegment returns the segment immediately before the iterated gap. If no
+// such segment exists, PrevSegment returns a terminal iterator.
+func (gap addrGapIterator) PrevSegment() addrIterator {
+ return addrsegmentBeforePosition(gap.node, gap.index)
+}
+
+// NextSegment returns the segment immediately after the iterated gap. If no
+// such segment exists, NextSegment returns a terminal iterator.
+func (gap addrGapIterator) NextSegment() addrIterator {
+ return addrsegmentAfterPosition(gap.node, gap.index)
+}
+
+// PrevGap returns the iterated gap's predecessor. If no such gap exists,
+// PrevGap returns a terminal iterator.
+func (gap addrGapIterator) PrevGap() addrGapIterator {
+ seg := gap.PrevSegment()
+ if !seg.Ok() {
+ return addrGapIterator{}
+ }
+ return seg.PrevGap()
+}
+
+// NextGap returns the iterated gap's successor. If no such gap exists, NextGap
+// returns a terminal iterator.
+func (gap addrGapIterator) NextGap() addrGapIterator {
+ seg := gap.NextSegment()
+ if !seg.Ok() {
+ return addrGapIterator{}
+ }
+ return seg.NextGap()
+}
+
+// NextLargeEnoughGap returns the iterated gap's first next gap with larger
+// length than minSize. If not found, return a terminal gap iterator (does NOT
+// include this gap itself).
+//
+// Precondition: trackGaps must be 1.
+func (gap addrGapIterator) NextLargeEnoughGap(minSize uintptr) addrGapIterator {
+ if addrtrackGaps != 1 {
+ panic("set is not tracking gaps")
+ }
+ if gap.node != nil && gap.node.hasChildren && gap.index == gap.node.nrSegments {
+
+ gap.node = gap.NextSegment().node
+ gap.index = 0
+ return gap.nextLargeEnoughGapHelper(minSize)
+ }
+ return gap.nextLargeEnoughGapHelper(minSize)
+}
+
+// nextLargeEnoughGapHelper is the helper function used by NextLargeEnoughGap
+// to do the real recursions.
+//
+// Preconditions: gap is NOT the trailing gap of a non-leaf node.
+func (gap addrGapIterator) nextLargeEnoughGapHelper(minSize uintptr) addrGapIterator {
+
+ for gap.node != nil &&
+ (gap.node.maxGap.Get() < minSize || (!gap.node.hasChildren && gap.index == gap.node.nrSegments)) {
+ gap.node, gap.index = gap.node.parent, gap.node.parentIndex
+ }
+
+ if gap.node == nil {
+ return addrGapIterator{}
+ }
+
+ gap.index++
+ for gap.index <= gap.node.nrSegments {
+ if gap.node.hasChildren {
+ if largeEnoughGap := gap.node.children[gap.index].searchFirstLargeEnoughGap(minSize); largeEnoughGap.Ok() {
+ return largeEnoughGap
+ }
+ } else {
+ if gap.Range().Length() >= minSize {
+ return gap
+ }
+ }
+ gap.index++
+ }
+ gap.node, gap.index = gap.node.parent, gap.node.parentIndex
+ if gap.node != nil && gap.index == gap.node.nrSegments {
+
+ gap.node, gap.index = gap.node.parent, gap.node.parentIndex
+ }
+ return gap.nextLargeEnoughGapHelper(minSize)
+}
+
+// PrevLargeEnoughGap returns the iterated gap's first prev gap with larger or
+// equal length than minSize. If not found, return a terminal gap iterator
+// (does NOT include this gap itself).
+//
+// Precondition: trackGaps must be 1.
+func (gap addrGapIterator) PrevLargeEnoughGap(minSize uintptr) addrGapIterator {
+ if addrtrackGaps != 1 {
+ panic("set is not tracking gaps")
+ }
+ if gap.node != nil && gap.node.hasChildren && gap.index == 0 {
+
+ gap.node = gap.PrevSegment().node
+ gap.index = gap.node.nrSegments
+ return gap.prevLargeEnoughGapHelper(minSize)
+ }
+ return gap.prevLargeEnoughGapHelper(minSize)
+}
+
+// prevLargeEnoughGapHelper is the helper function used by PrevLargeEnoughGap
+// to do the real recursions.
+//
+// Preconditions: gap is NOT the first gap of a non-leaf node.
+func (gap addrGapIterator) prevLargeEnoughGapHelper(minSize uintptr) addrGapIterator {
+
+ for gap.node != nil &&
+ (gap.node.maxGap.Get() < minSize || (!gap.node.hasChildren && gap.index == 0)) {
+ gap.node, gap.index = gap.node.parent, gap.node.parentIndex
+ }
+
+ if gap.node == nil {
+ return addrGapIterator{}
+ }
+
+ gap.index--
+ for gap.index >= 0 {
+ if gap.node.hasChildren {
+ if largeEnoughGap := gap.node.children[gap.index].searchLastLargeEnoughGap(minSize); largeEnoughGap.Ok() {
+ return largeEnoughGap
+ }
+ } else {
+ if gap.Range().Length() >= minSize {
+ return gap
+ }
+ }
+ gap.index--
+ }
+ gap.node, gap.index = gap.node.parent, gap.node.parentIndex
+ if gap.node != nil && gap.index == 0 {
+
+ gap.node, gap.index = gap.node.parent, gap.node.parentIndex
+ }
+ return gap.prevLargeEnoughGapHelper(minSize)
+}
+
+// segmentBeforePosition returns the predecessor segment of the position given
+// by n.children[i], which may or may not contain a child. If no such segment
+// exists, segmentBeforePosition returns a terminal iterator.
+func addrsegmentBeforePosition(n *addrnode, i int) addrIterator {
+ for i == 0 {
+ if n.parent == nil {
+ return addrIterator{}
+ }
+ n, i = n.parent, n.parentIndex
+ }
+ return addrIterator{n, i - 1}
+}
+
+// segmentAfterPosition returns the successor segment of the position given by
+// n.children[i], which may or may not contain a child. If no such segment
+// exists, segmentAfterPosition returns a terminal iterator.
+func addrsegmentAfterPosition(n *addrnode, i int) addrIterator {
+ for i == n.nrSegments {
+ if n.parent == nil {
+ return addrIterator{}
+ }
+ n, i = n.parent, n.parentIndex
+ }
+ return addrIterator{n, i}
+}
+
+func addrzeroValueSlice(slice []*objectEncodeState) {
+
+ for i := range slice {
+ addrSetFunctions{}.ClearValue(&slice[i])
+ }
+}
+
+func addrzeroNodeSlice(slice []*addrnode) {
+ for i := range slice {
+ slice[i] = nil
+ }
+}
+
+// String stringifies a Set for debugging.
+func (s *addrSet) String() string {
+ return s.root.String()
+}
+
+// String stringifies a node (and all of its children) for debugging.
+func (n *addrnode) String() string {
+ var buf bytes.Buffer
+ n.writeDebugString(&buf, "")
+ return buf.String()
+}
+
+func (n *addrnode) writeDebugString(buf *bytes.Buffer, prefix string) {
+ if n.hasChildren != (n.nrSegments > 0 && n.children[0] != nil) {
+ buf.WriteString(prefix)
+ buf.WriteString(fmt.Sprintf("WARNING: inconsistent value of hasChildren: got %v, want %v\n", n.hasChildren, !n.hasChildren))
+ }
+ for i := 0; i < n.nrSegments; i++ {
+ if child := n.children[i]; child != nil {
+ cprefix := fmt.Sprintf("%s- % 3d ", prefix, i)
+ if child.parent != n || child.parentIndex != i {
+ buf.WriteString(cprefix)
+ buf.WriteString(fmt.Sprintf("WARNING: inconsistent linkage to parent: got (%p, %d), want (%p, %d)\n", child.parent, child.parentIndex, n, i))
+ }
+ child.writeDebugString(buf, fmt.Sprintf("%s- % 3d ", prefix, i))
+ }
+ buf.WriteString(prefix)
+ if n.hasChildren {
+ if addrtrackGaps != 0 {
+ buf.WriteString(fmt.Sprintf("- % 3d: %v => %v, maxGap: %d\n", i, n.keys[i], n.values[i], n.maxGap.Get()))
+ } else {
+ buf.WriteString(fmt.Sprintf("- % 3d: %v => %v\n", i, n.keys[i], n.values[i]))
+ }
+ } else {
+ buf.WriteString(fmt.Sprintf("- % 3d: %v => %v\n", i, n.keys[i], n.values[i]))
+ }
+ }
+ if child := n.children[n.nrSegments]; child != nil {
+ child.writeDebugString(buf, fmt.Sprintf("%s- % 3d ", prefix, n.nrSegments))
+ }
+}
+
+// SegmentDataSlices represents segments from a set as slices of start, end, and
+// values. SegmentDataSlices is primarily used as an intermediate representation
+// for save/restore and the layout here is optimized for that.
+//
+// +stateify savable
+type addrSegmentDataSlices struct {
+ Start []uintptr
+ End []uintptr
+ Values []*objectEncodeState
+}
+
+// ExportSortedSlice returns a copy of all segments in the given set, in ascending
+// key order.
+func (s *addrSet) ExportSortedSlices() *addrSegmentDataSlices {
+ var sds addrSegmentDataSlices
+ for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() {
+ sds.Start = append(sds.Start, seg.Start())
+ sds.End = append(sds.End, seg.End())
+ sds.Values = append(sds.Values, seg.Value())
+ }
+ sds.Start = sds.Start[:len(sds.Start):len(sds.Start)]
+ sds.End = sds.End[:len(sds.End):len(sds.End)]
+ sds.Values = sds.Values[:len(sds.Values):len(sds.Values)]
+ return &sds
+}
+
+// ImportSortedSlice initializes the given set from the given slice.
+//
+// Preconditions:
+// * s must be empty.
+// * sds must represent a valid set (the segments in sds must have valid
+// lengths that do not overlap).
+// * The segments in sds must be sorted in ascending key order.
+func (s *addrSet) ImportSortedSlices(sds *addrSegmentDataSlices) error {
+ if !s.IsEmpty() {
+ return fmt.Errorf("cannot import into non-empty set %v", s)
+ }
+ gap := s.FirstGap()
+ for i := range sds.Start {
+ r := addrRange{sds.Start[i], sds.End[i]}
+ if !gap.Range().IsSupersetOf(r) {
+ return fmt.Errorf("segment overlaps a preceding segment or is incorrectly sorted: [%d, %d) => %v", sds.Start[i], sds.End[i], sds.Values[i])
+ }
+ gap = s.InsertWithoutMerging(gap, r, sds.Values[i]).NextGap()
+ }
+ return nil
+}
+
+// segmentTestCheck returns an error if s is incorrectly sorted, does not
+// contain exactly expectedSegments segments, or contains a segment which
+// fails the passed check.
+//
+// This should be used only for testing, and has been added to this package for
+// templating convenience.
+func (s *addrSet) segmentTestCheck(expectedSegments int, segFunc func(int, addrRange, *objectEncodeState) error) error {
+ havePrev := false
+ prev := uintptr(0)
+ nrSegments := 0
+ for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() {
+ next := seg.Start()
+ if havePrev && prev >= next {
+ return fmt.Errorf("incorrect order: key %d (segment %d) >= key %d (segment %d)", prev, nrSegments-1, next, nrSegments)
+ }
+ if segFunc != nil {
+ if err := segFunc(nrSegments, seg.Range(), seg.Value()); err != nil {
+ return err
+ }
+ }
+ prev = next
+ havePrev = true
+ nrSegments++
+ }
+ if nrSegments != expectedSegments {
+ return fmt.Errorf("incorrect number of segments: got %d, wanted %d", nrSegments, expectedSegments)
+ }
+ return nil
+}
+
+// countSegments counts the number of segments in the set.
+//
+// Similar to Check, this should only be used for testing.
+func (s *addrSet) countSegments() (segments int) {
+ for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() {
+ segments++
+ }
+ return segments
+}
+func (s *addrSet) saveRoot() *addrSegmentDataSlices {
+ return s.ExportSortedSlices()
+}
+
+func (s *addrSet) loadRoot(sds *addrSegmentDataSlices) {
+ if err := s.ImportSortedSlices(sds); err != nil {
+ panic(err)
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 18:41:24 +0000