54 lines
1.6 KiB
Go
54 lines
1.6 KiB
Go
// Copyright 2014 The 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 trie
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func keybytesToHex(str []byte) []byte {
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l := len(str)*2 + 1
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var nibbles = make([]byte, l)
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for i, b := range str {
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nibbles[i*2] = b / 16
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nibbles[i*2+1] = b % 16
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}
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nibbles[l-1] = 16
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return nibbles
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}
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// hexToKeyBytes turns hex nibbles into key bytes.
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// This can only be used for keys of even length.
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func hexToKeyBytes(hex []byte) []byte {
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if hasTerm(hex) {
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hex = hex[:len(hex)-1]
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}
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if len(hex)&1 != 0 {
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panic("can't convert hex key of odd length")
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}
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key := make([]byte, len(hex)/2)
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decodeNibbles(hex, key)
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return key
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}
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func decodeNibbles(nibbles []byte, bytes []byte) {
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for bi, ni := 0, 0; ni < len(nibbles); bi, ni = bi+1, ni+2 {
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bytes[bi] = nibbles[ni]<<4 | nibbles[ni+1]
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}
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}
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// hasTerm returns whether a hex key has the terminator flag.
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func hasTerm(s []byte) bool {
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return len(s) > 0 && s[len(s)-1] == 16
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}
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