package mpt import ( "encoding/json" "errors" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/util" ) const ( // childrenCount represents a number of children of a branch node. childrenCount = 17 // lastChild is the index of the last child. lastChild = childrenCount - 1 ) // BranchNode represents MPT's branch node. type BranchNode struct { BaseNode Children [childrenCount]Node } var _ Node = (*BranchNode)(nil) // NewBranchNode returns new branch node. func NewBranchNode() *BranchNode { b := new(BranchNode) for i := 0; i < childrenCount; i++ { b.Children[i] = EmptyNode{} } return b } // Type implements Node interface. func (b *BranchNode) Type() NodeType { return BranchT } // Hash implements BaseNode interface. func (b *BranchNode) Hash() util.Uint256 { return b.getHash(b) } // Bytes implements BaseNode interface. func (b *BranchNode) Bytes() []byte { return b.getBytes(b) } // Size implements Node interface. func (b *BranchNode) Size() int { sz := childrenCount for i := range b.Children { if !isEmpty(b.Children[i]) { sz += util.Uint256Size } } return sz } // EncodeBinary implements io.Serializable. func (b *BranchNode) EncodeBinary(w *io.BinWriter) { for i := 0; i < childrenCount; i++ { encodeBinaryAsChild(b.Children[i], w) } } // DecodeBinary implements io.Serializable. func (b *BranchNode) DecodeBinary(r *io.BinReader) { for i := 0; i < childrenCount; i++ { no := new(NodeObject) no.DecodeBinary(r) b.Children[i] = no.Node } } // MarshalJSON implements json.Marshaler. func (b *BranchNode) MarshalJSON() ([]byte, error) { return json.Marshal(b.Children) } // UnmarshalJSON implements json.Unmarshaler. func (b *BranchNode) UnmarshalJSON(data []byte) error { var obj NodeObject if err := obj.UnmarshalJSON(data); err != nil { return err } else if u, ok := obj.Node.(*BranchNode); ok { *b = *u return nil } return errors.New("expected branch node") } // splitPath splits path for a branch node. func splitPath(path []byte) (byte, []byte) { if len(path) != 0 { return path[0], path[1:] } return lastChild, path }