119 lines
2.7 KiB
Go
119 lines
2.7 KiB
Go
// Copyright 2014 The Cayley Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package memstore
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import (
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"fmt"
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"math"
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"strings"
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"github.com/petar/GoLLRB/llrb"
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"github.com/google/cayley/graph"
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)
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type Iterator struct {
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graph.BaseIterator
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tree *llrb.LLRB
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data string
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isRunning bool
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iterLast Int64
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}
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type Int64 int64
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func (i Int64) Less(than llrb.Item) bool {
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return i < than.(Int64)
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}
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func IterateOne(tree *llrb.LLRB, last Int64) Int64 {
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var next Int64
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tree.AscendGreaterOrEqual(last, func(i llrb.Item) bool {
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if i.(Int64) == last {
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return true
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} else {
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next = i.(Int64)
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return false
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}
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})
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return next
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}
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func NewLlrbIterator(tree *llrb.LLRB, data string) *Iterator {
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var it Iterator
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graph.BaseIteratorInit(&it.BaseIterator)
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it.tree = tree
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it.iterLast = Int64(-1)
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it.data = data
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return &it
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}
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func (it *Iterator) Reset() {
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it.iterLast = Int64(-1)
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}
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func (it *Iterator) Clone() graph.Iterator {
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var new_it = NewLlrbIterator(it.tree, it.data)
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new_it.CopyTagsFrom(it)
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return new_it
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}
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func (it *Iterator) Close() {}
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func (it *Iterator) Next() (graph.TSVal, bool) {
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graph.NextLogIn(it)
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if it.tree.Max() == nil || it.Last == int64(it.tree.Max().(Int64)) {
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return graph.NextLogOut(it, nil, false)
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}
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it.iterLast = IterateOne(it.tree, it.iterLast)
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it.Last = int64(it.iterLast)
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return graph.NextLogOut(it, it.Last, true)
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}
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func (it *Iterator) Size() (int64, bool) {
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return int64(it.tree.Len()), true
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}
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func (it *Iterator) Check(v graph.TSVal) bool {
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graph.CheckLogIn(it, v)
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if it.tree.Has(Int64(v.(int64))) {
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it.Last = v
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return graph.CheckLogOut(it, v, true)
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}
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return graph.CheckLogOut(it, v, false)
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}
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func (it *Iterator) DebugString(indent int) string {
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size, _ := it.Size()
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return fmt.Sprintf("%s(%s tags:%s size:%d %s)", strings.Repeat(" ", indent), it.Type(), it.Tags(), size, it.data)
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}
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func (it *Iterator) Type() string {
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return "llrb"
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}
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func (it *Iterator) Sorted() bool {
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return true
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}
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func (it *Iterator) Optimize() (graph.Iterator, bool) {
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return it, false
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}
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func (it *Iterator) GetStats() *graph.IteratorStats {
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return &graph.IteratorStats{
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CheckCost: int64(math.Log(float64(it.tree.Len()))) + 1,
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NextCost: 1,
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Size: int64(it.tree.Len()),
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}
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}
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