Method Remove

pkg/segment/set.go:557–590

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.

(seg Iterator)

// All existing iterators (including seg, but not including the returned
// iterator) are invalidated.
func (s *Set) Remove(seg Iterator) GapIterator {
	// We only want to remove directly from a leaf node.
	if seg.node.hasChildren {
		// Since seg.node has children, the removed segment must have a
		// predecessor (at the end of the rightmost leaf of its left child
		// subtree). Move the contents of that predecessor into the removed
		// segment's position, and remove that predecessor instead. (We choose
		// to steal the predecessor rather than the successor because removing
		// from the end of a leaf node doesn't involve any copying unless
		// merging is required.)
		victim := seg.PrevSegment()
		// This must be unchecked since until victim is removed, seg and victim
		// overlap.
		seg.SetRangeUnchecked(victim.Range())
		seg.SetValue(victim.Value())
		// Need to update the nextAdjacentNode's maxGap because the gap in between
		// must have been modified by updating seg.Range() to victim.Range().
		// seg.NextSegment() must exist since the last segment can't be in a
		// non-leaf node.
		nextAdjacentNode := seg.NextSegment().node
		if trackGaps != 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])
	Functions{}.ClearValue(&seg.node.values[seg.node.nrSegments-1])
	seg.node.nrSegments--
	if trackGaps != 0 {
		seg.node.updateMaxGapLeaf()
	}
	return seg.node.rebalanceAfterRemove(GapIterator(seg))
}

// RemoveAll removes all segments from the set. All existing iterators are
// invalidated.