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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library 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"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
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 {
isIterStart := false
if self.Key == nil {
isIterStart = true
self.Key = make([]byte, 32)
}
key := remTerm(compactHexDecode(self.Key))
k := self.next(self.trie.root, key, isIterStart)
self.Key = []byte(decodeCompact(k))
return len(k) > 0
}
func (self *Iterator) next(node interface{}, key []byte, isIterStart bool) []byte {
if node == nil {
return nil
}
switch node := node.(type) {
case fullNode:
if len(key) > 0 {
k := self.next(node[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[i])
if k != nil {
return append([]byte{i}, k...)
}
}
case shortNode:
k := remTerm(node.Key)
if vnode, ok := node.Val.(valueNode); ok {
switch bytes.Compare([]byte(k), key) {
case 0:
if isIterStart {
self.Value = vnode
return k
}
case 1:
self.Value = vnode
return k
}
} else {
cnode := node.Val
var ret []byte
skey := key[len(k):]
if bytes.HasPrefix(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...)
}
}
case hashNode:
rn, err := self.trie.resolveHash(node, nil, nil)
if err != nil && glog.V(logger.Error) {
glog.Errorf("Unhandled trie error: %v", err)
}
return self.next(rn, key, isIterStart)
}
return nil
}
func (self *Iterator) key(node interface{}) []byte {
switch node := node.(type) {
case shortNode:
// Leaf node
k := remTerm(node.Key)
if vnode, ok := node.Val.(valueNode); ok {
self.Value = vnode
return k
}
return append(k, self.key(node.Val)...)
case fullNode:
if node[16] != nil {
self.Value = node[16].(valueNode)
return []byte{16}
}
for i := 0; i < 16; i++ {
k := self.key(node[i])
if k != nil {
return append([]byte{byte(i)}, k...)
}
}
case hashNode:
rn, err := self.trie.resolveHash(node, nil, nil)
if err != nil && glog.V(logger.Error) {
glog.Errorf("Unhandled trie error: %v", err)
}
return self.key(rn)
}
return nil
}
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