plugeth/trie/iterator.go

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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
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//
// The go-ethereum library is free software: you can redistribute it and/or modify
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// 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,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// 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/>.
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package trie
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import "bytes"
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type Iterator struct {
trie *Trie
Key []byte
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Value []byte
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}
func NewIterator(trie *Trie) *Iterator {
return &Iterator{trie: trie, Key: nil}
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}
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func (self *Iterator) Next() bool {
isIterStart := false
if self.Key == nil {
isIterStart = true
self.Key = make([]byte, 32)
}
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key := remTerm(compactHexDecode(self.Key))
k := self.next(self.trie.root, key, isIterStart)
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self.Key = []byte(decodeCompact(k))
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return len(k) > 0
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}
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func (self *Iterator) next(node interface{}, key []byte, isIterStart bool) []byte {
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if node == nil {
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return nil
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}
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switch node := node.(type) {
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case fullNode:
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if len(key) > 0 {
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k := self.next(node[key[0]], key[1:], isIterStart)
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if k != nil {
return append([]byte{key[0]}, k...)
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}
}
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var r byte
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if len(key) > 0 {
r = key[0] + 1
}
for i := r; i < 16; i++ {
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k := self.key(node[i])
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if k != nil {
return append([]byte{i}, k...)
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}
}
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case shortNode:
k := remTerm(node.Key)
if vnode, ok := node.Val.(valueNode); ok {
switch bytes.Compare([]byte(k), key) {
case 0:
if isIterStart {
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self.Value = vnode
return k
}
case 1:
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self.Value = vnode
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return k
}
} else {
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cnode := node.Val
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var ret []byte
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skey := key[len(k):]
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if bytes.HasPrefix(key, k) {
ret = self.next(cnode, skey, isIterStart)
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} else if bytes.Compare(k, key[:len(k)]) > 0 {
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return self.key(node)
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}
if ret != nil {
return append(k, ret...)
}
}
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case hashNode:
return self.next(self.trie.resolveHash(node), key, isIterStart)
}
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return nil
}
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func (self *Iterator) key(node interface{}) []byte {
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switch node := node.(type) {
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case shortNode:
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// Leaf node
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k := remTerm(node.Key)
if vnode, ok := node.Val.(valueNode); ok {
self.Value = vnode
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return k
}
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return append(k, self.key(node.Val)...)
case fullNode:
if node[16] != nil {
self.Value = node[16].(valueNode)
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return []byte{16}
}
for i := 0; i < 16; i++ {
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k := self.key(node[i])
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if k != nil {
return append([]byte{byte(i)}, k...)
}
}
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case hashNode:
return self.key(self.trie.resolveHash(node))
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}
return nil
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}