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btree.go
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btree.go
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// Copyright 2023 The nutsdb Author. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package nutsdb
import (
"bytes"
"errors"
"regexp"
"github.com/tidwall/btree"
)
// ErrKeyNotFound is returned when the key is not in the b tree.
var ErrKeyNotFound = errors.New("key not found")
type Item struct {
key []byte
record *Record
}
type BTree struct {
btree *btree.BTreeG[*Item]
}
func NewBTree() *BTree {
return &BTree{
btree: btree.NewBTreeG[*Item](func(a, b *Item) bool {
return bytes.Compare(a.key, b.key) == -1
}),
}
}
func (bt *BTree) Find(key []byte) (*Record, bool) {
item, ok := bt.btree.Get(&Item{key: key})
if ok {
return item.record, ok
}
return nil, ok
}
func (bt *BTree) Insert(record *Record) bool {
_, replaced := bt.btree.Set(&Item{key: record.Key, record: record})
return replaced
}
func (bt *BTree) InsertRecord(key []byte, record *Record) bool {
_, replaced := bt.btree.Set(&Item{key: key, record: record})
return replaced
}
func (bt *BTree) Delete(key []byte) bool {
_, deleted := bt.btree.Delete(&Item{key: key})
return deleted
}
func (bt *BTree) All() []*Record {
items := bt.btree.Items()
records := make([]*Record, len(items))
for i, item := range items {
records[i] = item.record
}
return records
}
func (bt *BTree) AllItems() []*Item {
items := bt.btree.Items()
return items
}
func (bt *BTree) Range(start, end []byte) []*Record {
records := make([]*Record, 0)
bt.btree.Ascend(&Item{key: start}, func(item *Item) bool {
if bytes.Compare(item.key, end) > 0 {
return false
}
records = append(records, item.record)
return true
})
return records
}
func (bt *BTree) PrefixScan(prefix []byte, offset, limitNum int) []*Record {
records := make([]*Record, 0)
bt.btree.Ascend(&Item{key: prefix}, func(item *Item) bool {
if !bytes.HasPrefix(item.key, prefix) {
return false
}
if offset > 0 {
offset--
return true
}
records = append(records, item.record)
limitNum--
return limitNum != 0
})
return records
}
func (bt *BTree) PrefixSearchScan(prefix []byte, reg string, offset, limitNum int) []*Record {
records := make([]*Record, 0)
rgx := regexp.MustCompile(reg)
bt.btree.Ascend(&Item{key: prefix}, func(item *Item) bool {
if !bytes.HasPrefix(item.key, prefix) {
return false
}
if offset > 0 {
offset--
return true
}
if !rgx.Match(bytes.TrimPrefix(item.key, prefix)) {
return true
}
records = append(records, item.record)
limitNum--
return limitNum != 0
})
return records
}
func (bt *BTree) Count() int {
return bt.btree.Len()
}
func (bt *BTree) PopMin() (*Item, bool) {
return bt.btree.PopMin()
}
func (bt *BTree) PopMax() (*Item, bool) {
return bt.btree.PopMax()
}
func (bt *BTree) Min() (*Item, bool) {
return bt.btree.Min()
}
func (bt *BTree) Max() (*Item, bool) {
return bt.btree.Max()
}