seaweedfs/weed/storage/needle/btree_map.go

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2017-05-27 05:51:25 +00:00
package needle
import (
"github.com/google/btree"
)
//This map assumes mostly inserting increasing keys
type BtreeMap struct {
tree *btree.BTree
}
func NewBtreeMap() *BtreeMap {
return &BtreeMap{
tree: btree.New(32),
}
}
func (cm *BtreeMap) Set(key Key, offset, size uint32) (oldOffset, oldSize uint32) {
found := cm.tree.ReplaceOrInsert(NeedleValue{key, offset, size})
if found != nil {
old := found.(NeedleValue)
return old.Offset, old.Size
}
return
}
func (cm *BtreeMap) Delete(key Key) (oldSize uint32) {
found := cm.tree.Delete(NeedleValue{key, 0, 0})
if found != nil {
old := found.(NeedleValue)
return old.Size
}
return
}
func (cm *BtreeMap) Get(key Key) (*NeedleValue, bool) {
found := cm.tree.Get(NeedleValue{key, 0, 0})
if found != nil {
old := found.(NeedleValue)
return &old, true
}
return nil, false
}
// Visit visits all entries or stop if any error when visiting
func (cm *BtreeMap) Visit(visit func(NeedleValue) error) (ret error) {
cm.tree.Ascend(func(item btree.Item) bool {
needle := item.(NeedleValue)
ret = visit(needle)
return ret == nil
})
return ret
}