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rlp.go
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rlp.go
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package ompt
import (
"errors"
"fmt"
cerrors "github.com/icon-project/goloop/common/errors"
)
var (
errRLPNotEnoughBytes = errors.New("RLP:Not enough bytes to decode")
errRLPInvalidEncoding = errors.New("RLP:Invalid encoding")
)
func rlpReadSize(b []byte, slen byte) (uint64, error) {
if int(slen) > len(b) {
return 0, cerrors.WithStack(errRLPNotEnoughBytes)
}
var s uint64
switch slen {
case 1:
s = uint64(b[0])
case 2:
s = uint64(b[0])<<8 | uint64(b[1])
case 3:
s = uint64(b[0])<<16 | uint64(b[1])<<8 | uint64(b[2])
case 4:
s = uint64(b[0])<<24 | uint64(b[1])<<16 | uint64(b[2])<<8 | uint64(b[3])
case 5:
s = uint64(b[0])<<32 | uint64(b[1])<<24 | uint64(b[2])<<16 | uint64(b[3])<<8 | uint64(b[4])
case 6:
s = uint64(b[0])<<40 | uint64(b[1])<<32 | uint64(b[2])<<24 | uint64(b[3])<<16 | uint64(b[4])<<8 | uint64(b[5])
case 7:
s = uint64(b[0])<<48 | uint64(b[1])<<40 | uint64(b[2])<<32 | uint64(b[3])<<24 | uint64(b[4])<<16 | uint64(b[5])<<8 | uint64(b[6])
case 8:
s = uint64(b[0])<<56 | uint64(b[1])<<48 | uint64(b[2])<<40 | uint64(b[3])<<32 | uint64(b[4])<<24 | uint64(b[5])<<16 | uint64(b[6])<<8 | uint64(b[7])
}
if s < 56 || b[0] == 0 {
return 0, cerrors.WithStack(errRLPInvalidEncoding)
}
return s, nil
}
func rlpParseHeader(buf []byte) (bool, uint64, uint64, error) {
if len(buf) == 0 {
return false, 0, 0, cerrors.WithStack(errRLPNotEnoughBytes)
}
b := buf[0]
var tagsize uint64
var contentsize uint64
var err error
var islist bool
switch {
case b < 0x80:
tagsize = 0
contentsize = 1
case b < 0xB8:
tagsize = 1
contentsize = uint64(b - 0x80)
// Reject strings that should've been single bytes.
if contentsize == 1 && len(buf) > 1 && buf[1] < 128 {
return false, 0, 0, cerrors.WithStack(errRLPInvalidEncoding)
}
case b < 0xC0:
tagsize = uint64(b-0xB7) + 1
contentsize, err = rlpReadSize(buf[1:], b-0xB7)
case b < 0xF8:
islist = true
tagsize = 1
contentsize = uint64(b - 0xC0)
default:
islist = true
tagsize = uint64(b-0xF7) + 1
contentsize, err = rlpReadSize(buf[1:], b-0xF7)
}
if err != nil {
return false, 0, 0, err
}
// Reject values larger than the input slice.
if contentsize > uint64(len(buf))-tagsize {
return false, 0, 0, cerrors.WithStack(errRLPNotEnoughBytes)
}
return islist, tagsize, contentsize, err
}
func rlpParseList(b []byte) ([][]byte, error) {
islist, tsize, csize, err := rlpParseHeader(b)
if err != nil {
return nil, err
}
if !islist {
return nil, cerrors.WithStack(cerrors.ErrIllegalArgument)
}
if uint64(len(b)) < tsize+csize {
return nil, cerrors.WithStack(errRLPNotEnoughBytes)
}
b = b[tsize : tsize+csize]
var items = [][]byte{}
for len(b) > 0 {
_, tsize, csize, err := rlpParseHeader(b)
if err != nil {
return nil, err
}
if uint64(len(b)) < tsize+csize {
return nil, cerrors.WithStack(errRLPNotEnoughBytes)
}
items = append(items, b[:tsize+csize])
b = b[tsize+csize:]
}
return items, nil
}
func rlpParseBytes(b []byte) ([]byte, error) {
islist, tsize, csize, err := rlpParseHeader(b)
if err != nil {
return nil, err
}
if islist {
return nil, cerrors.WithStack(cerrors.ErrIllegalArgument)
}
if uint64(len(b)) < tsize+csize {
return nil, cerrors.WithStack(errRLPNotEnoughBytes)
}
return b[tsize : tsize+csize], nil
}
func rlpCountBytesForSize(b int) int {
var cnt = int(1)
for b >>= 8; b > 0; cnt++ {
b >>= 8
}
return cnt
}
func rlpEncodeBytes(b []byte) []byte {
var blen = len(b)
if blen == 1 && b[0] < 0x80 {
return b
}
if blen <= 55 {
buf := make([]byte, blen+1)
buf[0] = byte(0x80 + blen)
copy(buf[1:], b)
return buf
}
tslen := rlpCountBytesForSize(blen)
buf := make([]byte, 1+tslen+blen)
buf[0] = byte(0x80 + 55 + tslen)
for tsidx := tslen; tsidx > 0; tsidx-- {
buf[tsidx] = byte(blen & 0xff)
blen >>= 8
}
copy(buf[tslen+1:], b)
return buf
}
func rlpEncodeList(blist [][]byte) []byte {
blen := 0
for _, b := range blist {
blen += len(b)
}
if blen <= 55 {
buf := make([]byte, blen+1)
buf[0] = byte(0xC0 + blen)
bidx := buf[1:]
for _, b := range blist {
copy(bidx, b)
bidx = bidx[len(b):]
}
return buf
}
tslen := rlpCountBytesForSize(blen)
buf := make([]byte, 1+tslen+blen)
buf[0] = byte(0xC0 + 55 + tslen)
for tsidx := tslen; tsidx > 0; tsidx-- {
buf[tsidx] = byte(blen & 0xff)
blen >>= 8
}
bidx := buf[1+tslen:]
for _, b := range blist {
copy(bidx, b)
bidx = bidx[len(b):]
}
return buf
}
type RLPEncoder interface {
RLPEncode(o interface{}) error
RLPWrite(b []byte)
}
type rlpListEncoder struct {
data [][]byte
}
func (e *rlpListEncoder) RLPEncode(o interface{}) error {
b, err := rlpEncode(o)
if err != nil {
return err
}
e.data = append(e.data, b)
return nil
}
func (e *rlpListEncoder) RLPWrite(b []byte) {
e.data = append(e.data, b)
}
func (e *rlpListEncoder) RLPSerialize() []byte {
return rlpEncodeList(e.data)
}
type RLPListEncoder interface {
RLPListSize() int
RLPListEncode(e RLPEncoder) error
}
type RLPSerializer interface {
RLPSerialize() []byte
}
func rlpEncode(o interface{}) ([]byte, error) {
switch o := o.(type) {
case []byte:
return rlpEncodeBytes(o), nil
case [][]byte:
blist := make([][]byte, len(o))
for i := range blist {
blist[i] = rlpEncodeBytes(o[i])
}
return rlpEncodeList(blist), nil
case []interface{}:
blist := make([][]byte, len(o))
for i := range blist {
b, err := rlpEncode(o[i])
if err != nil {
return nil, err
}
blist[i] = b
}
return rlpEncodeList(blist), nil
case RLPListEncoder:
sz := o.RLPListSize()
e := &rlpListEncoder{make([][]byte, 0, sz)}
if err := o.RLPListEncode(e); err != nil {
return nil, err
}
return e.RLPSerialize(), nil
case RLPSerializer:
return o.RLPSerialize(), nil
case nil:
return rlpEncodeBytes(nil), nil
default:
return nil, fmt.Errorf("Fail to encode object type %T", o)
}
}