bump buntdb to v1.2.3

Potentially fixes the database corruption seen on #1603

vendor/github.com/tidwall/rtred/base/load.go

@@ -0,0 +1,97 @@
+package base
+
+import "math"
+
+// Load bulk load items into the R-tree.
+func (tr *RTree) Load(mins, maxs [][]float64, items []interface{}) {
+	if len(items) < tr.minEntries {
+		for i := 0; i < len(items); i++ {
+			tr.Insert(mins[i], maxs[i], items[i])
+		}
+		return
+	}
+
+	// prefill the items
+	fitems := make([]*treeNode, len(items))
+	for i := 0; i < len(items); i++ {
+		item := &treeItem{min: mins[i], max: maxs[i], item: items[i]}
+		fitems[i] = item.unsafeNode()
+	}
+
+	// following equations are defined in the paper describing OMT
+	N := len(fitems)
+	M := tr.maxEntries
+	h := int(math.Ceil(math.Log(float64(N)) / math.Log(float64(M))))
+	Nsubtree := int(math.Pow(float64(M), float64(h-1)))
+	S := int(math.Ceil(math.Sqrt(float64(N) / float64(Nsubtree))))
+
+	// sort by the initial axis
+	axis := 0
+	sortByAxis(fitems, axis)
+
+	// build the root node. it's split differently from the subtrees.
+	children := make([]*treeNode, 0, S)
+	for i := 0; i < S; i++ {
+		var part []*treeNode
+		if i == S-1 {
+			// last split
+			part = fitems[len(fitems)/S*i:]
+		} else {
+			part = fitems[len(fitems)/S*i : len(fitems)/S*(i+1)]
+		}
+		children = append(children, tr.omt(part, h-1, axis+1))
+	}
+
+	node := tr.createNode(children)
+	node.leaf = false
+	node.height = h
+	tr.calcBBox(node)
+
+	if tr.data.count == 0 {
+		// save as is if tree is empty
+		tr.data = node
+	} else if tr.data.height == node.height {
+		// split root if trees have the same height
+		tr.splitRoot(tr.data, node)
+	} else {
+		if tr.data.height < node.height {
+			// swap trees if inserted one is bigger
+			tr.data, node = node, tr.data
+		}
+
+		// insert the small tree into the large tree at appropriate level
+		tr.insert(node, nil, tr.data.height-node.height-1, true)
+	}
+}
+
+func (tr *RTree) omt(fitems []*treeNode, h, axis int) *treeNode {
+	if len(fitems) <= tr.maxEntries {
+		// reached leaf level; return leaf
+		children := make([]*treeNode, len(fitems))
+		copy(children, fitems)
+		node := tr.createNode(children)
+		node.height = h
+		tr.calcBBox(node)
+		return node
+	}
+
+	// sort the items on a different axis than the previous level.
+	sortByAxis(fitems, axis%tr.dims)
+	children := make([]*treeNode, 0, tr.maxEntries)
+	partsz := len(fitems) / tr.maxEntries
+	for i := 0; i < tr.maxEntries; i++ {
+		var part []*treeNode
+		if i == tr.maxEntries-1 {
+			// last part
+			part = fitems[partsz*i:]
+		} else {
+			part = fitems[partsz*i : partsz*(i+1)]
+		}
+		children = append(children, tr.omt(part, h-1, axis+1))
+	}
+	node := tr.createNode(children)
+	node.height = h
+	node.leaf = false
+	tr.calcBBox(node)
+	return node
+}