plugeth/trie/encoding.go
2015-01-29 23:17:43 +01:00

77 lines
1.3 KiB
Go

package trie
import (
"bytes"
"encoding/hex"
"strings"
)
func CompactEncode(hexSlice []byte) string {
terminator := 0
if hexSlice[len(hexSlice)-1] == 16 {
terminator = 1
}
if terminator == 1 {
hexSlice = hexSlice[:len(hexSlice)-1]
}
oddlen := len(hexSlice) % 2
flags := byte(2*terminator + oddlen)
if oddlen != 0 {
hexSlice = append([]byte{flags}, hexSlice...)
} else {
hexSlice = append([]byte{flags, 0}, hexSlice...)
}
var buff bytes.Buffer
for i := 0; i < len(hexSlice); i += 2 {
buff.WriteByte(byte(16*hexSlice[i] + hexSlice[i+1]))
}
return buff.String()
}
func CompactDecode(str string) []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 string) []byte {
base := "0123456789abcdef"
var hexSlice []byte
enc := hex.EncodeToString([]byte(str))
for _, v := range enc {
hexSlice = append(hexSlice, byte(strings.IndexByte(base, byte(v))))
}
hexSlice = append(hexSlice, 16)
return hexSlice
}
func DecodeCompact(key []byte) string {
const base = "0123456789abcdef"
var str string
for _, v := range key {
if v < 16 {
str += string(base[v])
}
}
res, err := hex.DecodeString(str)
return string(res)
}