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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package trie
import (
"bytes"
)
type Iterator struct {
trie *Trie
Key []byte
Value []byte
}
func NewIterator(trie *Trie) *Iterator {
return &Iterator{trie: trie, Key: nil}
}
func (self *Iterator) Next() bool {
self.trie.mu.Lock()
defer self.trie.mu.Unlock()
isIterStart := false
if self.Key == nil {
isIterStart = true
self.Key = make([]byte, 32)
}
key := RemTerm(CompactHexDecode(string(self.Key)))
k := self.next(self.trie.root, key, isIterStart)
self.Key = []byte(DecodeCompact(k))
return len(k) > 0
}
func (self *Iterator) next(node Node, key []byte, isIterStart bool) []byte {
if node == nil {
return nil
}
switch node := node.(type) {
case *FullNode:
if len(key) > 0 {
k := self.next(node.branch(key[0]), key[1:], isIterStart)
if k != nil {
return append([]byte{key[0]}, k...)
}
}
var r byte
if len(key) > 0 {
r = key[0] + 1
}
for i := r; i < 16; i++ {
k := self.key(node.branch(byte(i)))
if k != nil {
return append([]byte{i}, k...)
}
}
case *ShortNode:
k := RemTerm(node.Key())
if vnode, ok := node.Value().(*ValueNode); ok {
switch bytes.Compare([]byte(k), key) {
case 0:
if isIterStart {
self.Value = vnode.Val()
return k
}
case 1:
self.Value = vnode.Val()
return k
}
} else {
cnode := node.Value()
var ret []byte
skey := key[len(k):]
if BeginsWith(key, k) {
ret = self.next(cnode, skey, isIterStart)
} else if bytes.Compare(k, key[:len(k)]) > 0 {
return self.key(node)
}
if ret != nil {
return append(k, ret...)
}
}
}
return nil
}
func (self *Iterator) key(node Node) []byte {
switch node := node.(type) {
case *ShortNode:
// Leaf node
if vnode, ok := node.Value().(*ValueNode); ok {
k := RemTerm(node.Key())
self.Value = vnode.Val()
return k
} else {
k := RemTerm(node.Key())
return append(k, self.key(node.Value())...)
}
case *FullNode:
if node.Value() != nil {
self.Value = node.Value().(*ValueNode).Val()
return []byte{16}
}
for i := 0; i < 16; i++ {
k := self.key(node.branch(byte(i)))
if k != nil {
return append([]byte{byte(i)}, k...)
}
}
}
return nil
}
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