112 lines
1.9 KiB
Go
112 lines
1.9 KiB
Go
package trie
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import "bytes"
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type Iterator struct {
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trie *Trie
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Key []byte
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Value []byte
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}
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func NewIterator(trie *Trie) *Iterator {
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return &Iterator{trie: trie, Key: make([]byte, 32)}
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}
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func (self *Iterator) Next() bool {
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self.trie.mu.Lock()
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defer self.trie.mu.Unlock()
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key := RemTerm(CompactHexDecode(string(self.Key)))
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k := self.next(self.trie.root, key)
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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 Node, key []byte) []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.branch(key[0]), key[1:])
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if k != nil {
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return append([]byte{key[0]}, k...)
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}
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}
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var r byte
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if len(key) > 0 {
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r = key[0] + 1
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}
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for i := r; i < 16; i++ {
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k := self.key(node.branch(byte(i)))
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if k != nil {
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return append([]byte{i}, k...)
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}
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}
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case *ShortNode:
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k := RemTerm(node.Key())
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if vnode, ok := node.Value().(*ValueNode); ok {
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if bytes.Compare([]byte(k), key) > 0 {
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self.Value = vnode.Val()
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return k
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}
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} else {
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cnode := node.Value()
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var ret []byte
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skey := key[len(k):]
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if BeginsWith(key, k) {
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ret = self.next(cnode, skey)
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} else if bytes.Compare(k, key[:len(k)]) > 0 {
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ret = self.key(node)
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}
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if ret != nil {
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return append(k, ret...)
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}
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}
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}
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return nil
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}
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func (self *Iterator) key(node Node) []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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if vnode, ok := node.Value().(*ValueNode); ok {
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k := RemTerm(node.Key())
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self.Value = vnode.Val()
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return k
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} else {
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k := RemTerm(node.Key())
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return append(k, self.key(node.Value())...)
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}
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case *FullNode:
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if node.Value() != nil {
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self.Value = node.Value().(*ValueNode).Val()
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return []byte{16}
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}
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for i := 0; i < 16; i++ {
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k := self.key(node.branch(byte(i)))
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if k != nil {
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return append([]byte{byte(i)}, k...)
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}
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}
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}
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return nil
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}
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