mirror of https://github.com/status-im/op-geth.git
129 lines
2.7 KiB
Go
129 lines
2.7 KiB
Go
// Copyright 2014 The go-ethereum Authors
|
|
// This file is part of the go-ethereum library.
|
|
//
|
|
// The go-ethereum library is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// The go-ethereum library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public License
|
|
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package trie
|
|
|
|
func compactEncode(hexSlice []byte) []byte {
|
|
terminator := byte(0)
|
|
if hexSlice[len(hexSlice)-1] == 16 {
|
|
terminator = 1
|
|
hexSlice = hexSlice[:len(hexSlice)-1]
|
|
}
|
|
var (
|
|
odd = byte(len(hexSlice) % 2)
|
|
buflen = len(hexSlice)/2 + 1
|
|
bi, hi = 0, 0 // indices
|
|
hs = byte(0) // shift: flips between 0 and 4
|
|
)
|
|
if odd == 0 {
|
|
bi = 1
|
|
hs = 4
|
|
}
|
|
buf := make([]byte, buflen)
|
|
buf[0] = terminator<<5 | byte(odd)<<4
|
|
for bi < len(buf) && hi < len(hexSlice) {
|
|
buf[bi] |= hexSlice[hi] << hs
|
|
if hs == 0 {
|
|
bi++
|
|
}
|
|
hi, hs = hi+1, hs^(1<<2)
|
|
}
|
|
return buf
|
|
}
|
|
|
|
func compactDecode(str []byte) []byte {
|
|
base := compactHexDecode(str)
|
|
base = base[:len(base)-1]
|
|
if base[0] >= 2 {
|
|
base = append(base, 16)
|
|
}
|
|
if base[0]%2 == 1 {
|
|
base = base[1:]
|
|
} else {
|
|
base = base[2:]
|
|
}
|
|
return base
|
|
}
|
|
|
|
func compactHexDecode(str []byte) []byte {
|
|
l := len(str)*2 + 1
|
|
var nibbles = make([]byte, l)
|
|
for i, b := range str {
|
|
nibbles[i*2] = b / 16
|
|
nibbles[i*2+1] = b % 16
|
|
}
|
|
nibbles[l-1] = 16
|
|
return nibbles
|
|
}
|
|
|
|
// compactHexEncode encodes a series of nibbles into a byte array
|
|
func compactHexEncode(nibbles []byte) []byte {
|
|
nl := len(nibbles)
|
|
if nl == 0 {
|
|
return nil
|
|
}
|
|
if nibbles[nl-1] == 16 {
|
|
nl--
|
|
}
|
|
l := (nl + 1) / 2
|
|
var str = make([]byte, l)
|
|
for i, _ := range str {
|
|
b := nibbles[i*2] * 16
|
|
if nl > i*2 {
|
|
b += nibbles[i*2+1]
|
|
}
|
|
str[i] = b
|
|
}
|
|
return str
|
|
}
|
|
|
|
func decodeCompact(key []byte) []byte {
|
|
l := len(key) / 2
|
|
var res = make([]byte, l)
|
|
for i := 0; i < l; i++ {
|
|
v1, v0 := key[2*i], key[2*i+1]
|
|
res[i] = v1*16 + v0
|
|
}
|
|
return res
|
|
}
|
|
|
|
// prefixLen returns the length of the common prefix of a and b.
|
|
func prefixLen(a, b []byte) int {
|
|
var i, length = 0, len(a)
|
|
if len(b) < length {
|
|
length = len(b)
|
|
}
|
|
for ; i < length; i++ {
|
|
if a[i] != b[i] {
|
|
break
|
|
}
|
|
}
|
|
return i
|
|
}
|
|
|
|
func hasTerm(s []byte) bool {
|
|
return s[len(s)-1] == 16
|
|
}
|
|
|
|
func remTerm(s []byte) []byte {
|
|
if hasTerm(s) {
|
|
b := make([]byte, len(s)-1)
|
|
copy(b, s)
|
|
return b
|
|
}
|
|
return s
|
|
}
|