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53 lines
1.8 KiB
Go
53 lines
1.8 KiB
Go
// Copyright 2026 go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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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
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// 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
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package bintrie
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// NodeKind identifies the type of a trie node stored in a NodeRef.
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type NodeKind uint8
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const (
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KindEmpty NodeKind = iota
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KindInternal
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KindStem // up to 256 values per stem
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KindHashed
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)
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// NodeRef is a compact, GC-invisible reference to a node in a NodeStore.
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// It packs a 2-bit type tag (bits 31-30) and a 30-bit index (bits 29-0)
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// into a single uint32. Because NodeRef contains no Go pointers, slices
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// of structs containing NodeRef fields are allocated in noscan spans —
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// the garbage collector never examines them.
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type NodeRef uint32
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const (
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kindShift uint32 = 30
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indexMask uint32 = (1 << kindShift) - 1
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// EmptyRef represents an empty node.
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EmptyRef NodeRef = 0
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)
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func MakeRef(kind NodeKind, idx uint32) NodeRef {
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return NodeRef(uint32(kind)<<kindShift | (idx & indexMask))
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}
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func (r NodeRef) Kind() NodeKind { return NodeKind(uint32(r) >> kindShift) }
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// Index within the typed pool.
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func (r NodeRef) Index() uint32 { return uint32(r) & indexMask }
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func (r NodeRef) IsEmpty() bool { return r == EmptyRef }
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