neoneo-go/pkg/core/mpt/node.go
Evgenii Stratonikov dc6741bce7 mpt: implement MPT trie
MPT is a trie with a branching factor = 16, i.e. it consists of sequences in
16-element alphabet.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
2020-07-30 12:42:15 +03:00

70 lines
1.4 KiB
Go

package mpt
import (
"fmt"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/util"
)
// NodeType represents node type..
type NodeType byte
// Node types definitions.
const (
BranchT NodeType = 0x00
ExtensionT NodeType = 0x01
HashT NodeType = 0x02
LeafT NodeType = 0x03
)
// NodeObject represents Node together with it's type.
// It is used for serialization/deserialization where type info
// is also expected.
type NodeObject struct {
Node
}
// Node represents common interface of all MPT nodes.
type Node interface {
io.Serializable
Hash() util.Uint256
Type() NodeType
}
// EncodeBinary implements io.Serializable.
func (n NodeObject) EncodeBinary(w *io.BinWriter) {
encodeNodeWithType(n.Node, w)
}
// DecodeBinary implements io.Serializable.
func (n *NodeObject) DecodeBinary(r *io.BinReader) {
typ := NodeType(r.ReadB())
switch typ {
case BranchT:
n.Node = new(BranchNode)
case ExtensionT:
n.Node = new(ExtensionNode)
case HashT:
n.Node = new(HashNode)
case LeafT:
n.Node = new(LeafNode)
default:
r.Err = fmt.Errorf("invalid node type: %x", typ)
return
}
n.Node.DecodeBinary(r)
}
// encodeNodeWithType encodes node together with it's type.
func encodeNodeWithType(n Node, w *io.BinWriter) {
w.WriteB(byte(n.Type()))
n.EncodeBinary(w)
}
// toBytes is a helper for serializing node.
func toBytes(n Node) []byte {
buf := io.NewBufBinWriter()
encodeNodeWithType(n, buf.BinWriter)
return buf.Bytes()
}