80 lines
1.9 KiB
Go
80 lines
1.9 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 CompactEncode(hexSlice []byte) []byte {
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terminator := 0
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if hexSlice[len(hexSlice)-1] == 16 {
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terminator = 1
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}
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if terminator == 1 {
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hexSlice = hexSlice[:len(hexSlice)-1]
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}
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oddlen := len(hexSlice) % 2
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flags := byte(2*terminator + oddlen)
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if oddlen != 0 {
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hexSlice = append([]byte{flags}, hexSlice...)
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} else {
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hexSlice = append([]byte{flags, 0}, hexSlice...)
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}
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l := len(hexSlice) / 2
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var buf = make([]byte, l)
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for i := 0; i < l; i++ {
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buf[i] = 16*hexSlice[2*i] + hexSlice[2*i+1]
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}
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return buf
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}
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func CompactDecode(str []byte) []byte {
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base := CompactHexDecode(str)
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base = base[:len(base)-1]
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if base[0] >= 2 {
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base = append(base, 16)
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}
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if base[0]%2 == 1 {
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base = base[1:]
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} else {
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base = base[2:]
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}
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return base
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}
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func CompactHexDecode(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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func DecodeCompact(key []byte) []byte {
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l := len(key) / 2
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var res = make([]byte, l)
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for i := 0; i < l; i++ {
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v1, v0 := key[2*i], key[2*i+1]
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res[i] = v1*16 + v0
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}
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return res
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}
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