ipld-eth-statedb/trie_by_cid/trie/encoding.go
2023-04-09 12:01:26 -05:00

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