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861a1638e8
MPT is a trie with a branching factor = 16, i.e. it consists of sequences in 16-element alphabet.
70 lines
1.6 KiB
Go
70 lines
1.6 KiB
Go
package mpt
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import (
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"fmt"
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"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
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"github.com/nspcc-dev/neo-go/pkg/io"
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"github.com/nspcc-dev/neo-go/pkg/util"
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)
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// MaxKeyLength is the max length of the extension node key.
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const MaxKeyLength = 1125
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// ExtensionNode represents MPT's extension node.
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type ExtensionNode struct {
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hash util.Uint256
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valid bool
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key []byte
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next Node
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}
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var _ Node = (*ExtensionNode)(nil)
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// NewExtensionNode returns hash node with the specified key and next node.
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// Note: because it is a part of Trie, key must be mangled, i.e. must contain only bytes with high half = 0.
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func NewExtensionNode(key []byte, next Node) *ExtensionNode {
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return &ExtensionNode{
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key: key,
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next: next,
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}
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}
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// Type implements Node interface.
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func (e ExtensionNode) Type() NodeType { return ExtensionT }
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// Hash implements Node interface.
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func (e *ExtensionNode) Hash() util.Uint256 {
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if !e.valid {
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e.hash = hash.DoubleSha256(toBytes(e))
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e.valid = true
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}
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return e.hash
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}
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// invalidateHash invalidates node hash.
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func (e *ExtensionNode) invalidateHash() {
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e.valid = false
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}
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// DecodeBinary implements io.Serializable.
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func (e *ExtensionNode) DecodeBinary(r *io.BinReader) {
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sz := r.ReadVarUint()
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if sz > MaxKeyLength {
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r.Err = fmt.Errorf("extension node key is too big: %d", sz)
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return
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}
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e.valid = false
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e.key = make([]byte, sz)
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r.ReadBytes(e.key)
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e.next = new(HashNode)
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e.next.DecodeBinary(r)
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}
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// EncodeBinary implements io.Serializable.
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func (e ExtensionNode) EncodeBinary(w *io.BinWriter) {
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w.WriteVarBytes(e.key)
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n := NewHashNode(e.next.Hash())
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n.EncodeBinary(w)
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}
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