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rlp: support for uint256 (#26898)

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This adds built-in support in package rlp for encoding, decoding and generating code dealing with uint256.Int.

---------

Co-authored-by: Felix Lange <fjl@twurst.com>
This commit is contained in:
Martin Holst Swende 2023-03-17 06:51:55 -04:00 committed by GitHub
parent b7bfbc1e64
commit 58d0f6440b
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 316 additions and 2 deletions
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64
rlp/decode.go
View File

@ -29,6 +29,7 @@ import (
"sync"
"github.com/ethereum/go-ethereum/rlp/internal/rlpstruct"
"github.com/holiman/uint256"
)
//lint:ignore ST1012 EOL is not an error.
@ -52,6 +53,7 @@ var (
errUintOverflow = errors.New("rlp: uint overflow")
errNoPointer = errors.New("rlp: interface given to Decode must be a pointer")
errDecodeIntoNil = errors.New("rlp: pointer given to Decode must not be nil")
errUint256Large = errors.New("rlp: value too large for uint256")
streamPool = sync.Pool{
New: func() interface{} { return new(Stream) },
@ -148,6 +150,7 @@ func addErrorContext(err error, ctx string) error {
var (
decoderInterface = reflect.TypeOf(new(Decoder)).Elem()
bigInt = reflect.TypeOf(big.Int{})
u256Int = reflect.TypeOf(uint256.Int{})
)
func makeDecoder(typ reflect.Type, tags rlpstruct.Tags) (dec decoder, err error) {
@ -159,6 +162,10 @@ func makeDecoder(typ reflect.Type, tags rlpstruct.Tags) (dec decoder, err error)
return decodeBigInt, nil
case typ.AssignableTo(bigInt):
return decodeBigIntNoPtr, nil
case typ == reflect.PtrTo(u256Int):
return decodeU256, nil
case typ == u256Int:
return decodeU256NoPtr, nil
case kind == reflect.Ptr:
return makePtrDecoder(typ, tags)
case reflect.PtrTo(typ).Implements(decoderInterface):
@ -235,6 +242,24 @@ func decodeBigInt(s *Stream, val reflect.Value) error {
return nil
}
func decodeU256NoPtr(s *Stream, val reflect.Value) error {
return decodeU256(s, val.Addr())
}
func decodeU256(s *Stream, val reflect.Value) error {
i := val.Interface().(*uint256.Int)
if i == nil {
i = new(uint256.Int)
val.Set(reflect.ValueOf(i))
}
err := s.ReadUint256(i)
if err != nil {
return wrapStreamError(err, val.Type())
}
return nil
}
func makeListDecoder(typ reflect.Type, tag rlpstruct.Tags) (decoder, error) {
etype := typ.Elem()
if etype.Kind() == reflect.Uint8 && !reflect.PtrTo(etype).Implements(decoderInterface) {
@ -863,6 +888,45 @@ func (s *Stream) decodeBigInt(dst *big.Int) error {
return nil
}
// ReadUint256 decodes the next value as a uint256.
func (s *Stream) ReadUint256(dst *uint256.Int) error {
var buffer []byte
kind, size, err := s.Kind()
switch {
case err != nil:
return err
case kind == List:
return ErrExpectedString
case kind == Byte:
buffer = s.uintbuf[:1]
buffer[0] = s.byteval
s.kind = -1 // re-arm Kind
case size == 0:
// Avoid zero-length read.
s.kind = -1
case size <= uint64(len(s.uintbuf)):
// All possible uint256 values fit into s.uintbuf.
buffer = s.uintbuf[:size]
if err := s.readFull(buffer); err != nil {
return err
}
// Reject inputs where single byte encoding should have been used.
if size == 1 && buffer[0] < 128 {
return ErrCanonSize
}
default:
return errUint256Large
}
// Reject leading zero bytes.
if len(buffer) > 0 && buffer[0] == 0 {
return ErrCanonInt
}
// Set the integer bytes.
dst.SetBytes(buffer)
return nil
}
// Decode decodes a value and stores the result in the value pointed
// to by val. Please see the documentation for the Decode function
// to learn about the decoding rules.

42
rlp/decode_test.go
View File

@ -28,6 +28,7 @@ import (
"testing"
"github.com/ethereum/go-ethereum/common/math"
"github.com/holiman/uint256"
)
func TestStreamKind(t *testing.T) {
@ -468,6 +469,10 @@ var (
veryVeryBigInt = new(big.Int).Exp(veryBigInt, big.NewInt(8), nil)
)
var (
veryBigInt256, _ = uint256.FromBig(veryBigInt)
)
var decodeTests = []decodeTest{
// booleans
{input: "01", ptr: new(bool), value: true},
@ -541,11 +546,27 @@ var decodeTests = []decodeTest{
{input: "89FFFFFFFFFFFFFFFFFF", ptr: new(*big.Int), value: veryBigInt},
{input: "B848FFFFFFFFFFFFFFFFF800000000000000001BFFFFFFFFFFFFFFFFC8000000000000000045FFFFFFFFFFFFFFFFC800000000000000001BFFFFFFFFFFFFFFFFF8000000000000000001", ptr: new(*big.Int), value: veryVeryBigInt},
{input: "10", ptr: new(big.Int), value: *big.NewInt(16)}, // non-pointer also works
// big int errors
{input: "C0", ptr: new(*big.Int), error: "rlp: expected input string or byte for *big.Int"},
{input: "00", ptr: new(*big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"},
{input: "820001", ptr: new(*big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"},
{input: "8105", ptr: new(*big.Int), error: "rlp: non-canonical size information for *big.Int"},
// uint256
{input: "80", ptr: new(*uint256.Int), value: uint256.NewInt(0)},
{input: "01", ptr: new(*uint256.Int), value: uint256.NewInt(1)},
{input: "88FFFFFFFFFFFFFFFF", ptr: new(*uint256.Int), value: uint256.NewInt(math.MaxUint64)},
{input: "89FFFFFFFFFFFFFFFFFF", ptr: new(*uint256.Int), value: veryBigInt256},
{input: "10", ptr: new(uint256.Int), value: *uint256.NewInt(16)}, // non-pointer also works
// uint256 errors
{input: "C0", ptr: new(*uint256.Int), error: "rlp: expected input string or byte for *uint256.Int"},
{input: "00", ptr: new(*uint256.Int), error: "rlp: non-canonical integer (leading zero bytes) for *uint256.Int"},
{input: "820001", ptr: new(*uint256.Int), error: "rlp: non-canonical integer (leading zero bytes) for *uint256.Int"},
{input: "8105", ptr: new(*uint256.Int), error: "rlp: non-canonical size information for *uint256.Int"},
{input: "A1FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00", ptr: new(*uint256.Int), error: "rlp: value too large for uint256"},
// structs
{
input: "C50583343434",
@ -1223,6 +1244,27 @@ func BenchmarkDecodeBigInts(b *testing.B) {
}
}
func BenchmarkDecodeU256Ints(b *testing.B) {
ints := make([]*uint256.Int, 200)
for i := range ints {
ints[i], _ = uint256.FromBig(math.BigPow(2, int64(i)))
}
enc, err := EncodeToBytes(ints)
if err != nil {
b.Fatal(err)
}
b.SetBytes(int64(len(enc)))
b.ReportAllocs()
b.ResetTimer()
var out []*uint256.Int
for i := 0; i < b.N; i++ {
if err := DecodeBytes(enc, &out); err != nil {
b.Fatal(err)
}
}
}
func encodeTestSlice(n uint) []byte {
s := make([]uint, n)
for i := uint(0); i < n; i++ {

25
rlp/encbuffer.go
View File

@ -17,10 +17,13 @@
package rlp
import (
"encoding/binary"
"io"
"math/big"
"reflect"
"sync"
"github.com/holiman/uint256"
)
type encBuffer struct {
@ -169,6 +172,23 @@ func (w *encBuffer) writeBigInt(i *big.Int) {
}
}
// writeUint256 writes z as an integer.
func (w *encBuffer) writeUint256(z *uint256.Int) {
bitlen := z.BitLen()
if bitlen <= 64 {
w.writeUint64(z.Uint64())
return
}
nBytes := byte((bitlen + 7) / 8)
var b [33]byte
binary.BigEndian.PutUint64(b[1:9], z[3])
binary.BigEndian.PutUint64(b[9:17], z[2])
binary.BigEndian.PutUint64(b[17:25], z[1])
binary.BigEndian.PutUint64(b[25:33], z[0])
b[32-nBytes] = 0x80 + nBytes
w.str = append(w.str, b[32-nBytes:]...)
}
// list adds a new list header to the header stack. It returns the index of the header.
// Call listEnd with this index after encoding the content of the list.
func (buf *encBuffer) list() int {
@ -376,6 +396,11 @@ func (w EncoderBuffer) WriteBigInt(i *big.Int) {
w.buf.writeBigInt(i)
}
// WriteUint256 encodes uint256.Int as an RLP string.
func (w EncoderBuffer) WriteUint256(i *uint256.Int) {
w.buf.writeUint256(i)
}
// WriteBytes encodes b as an RLP string.
func (w EncoderBuffer) WriteBytes(b []byte) {
w.buf.writeBytes(b)

21
rlp/encode.go
View File

@ -24,6 +24,7 @@ import (
"reflect"
"github.com/ethereum/go-ethereum/rlp/internal/rlpstruct"
"github.com/holiman/uint256"
)
var (
@ -144,6 +145,10 @@ func makeWriter(typ reflect.Type, ts rlpstruct.Tags) (writer, error) {
return writeBigIntPtr, nil
case typ.AssignableTo(bigInt):
return writeBigIntNoPtr, nil
case typ == reflect.PtrTo(u256Int):
return writeU256IntPtr, nil
case typ == u256Int:
return writeU256IntNoPtr, nil
case kind == reflect.Ptr:
return makePtrWriter(typ, ts)
case reflect.PtrTo(typ).Implements(encoderInterface):
@ -206,6 +211,22 @@ func writeBigIntNoPtr(val reflect.Value, w *encBuffer) error {
return nil
}
func writeU256IntPtr(val reflect.Value, w *encBuffer) error {
ptr := val.Interface().(*uint256.Int)
if ptr == nil {
w.str = append(w.str, 0x80)
return nil
}
w.writeUint256(ptr)
return nil
}
func writeU256IntNoPtr(val reflect.Value, w *encBuffer) error {
i := val.Interface().(uint256.Int)
w.writeUint256(&i)
return nil
}
func writeBytes(val reflect.Value, w *encBuffer) error {
w.writeBytes(val.Bytes())
return nil

49
rlp/encode_test.go
View File

@ -27,6 +27,7 @@ import (
"testing"
"github.com/ethereum/go-ethereum/common/math"
"github.com/holiman/uint256"
)
type testEncoder struct {
@ -147,6 +148,30 @@ var encTests = []encTest{
{val: big.NewInt(-1), error: "rlp: cannot encode negative big.Int"},
{val: *big.NewInt(-1), error: "rlp: cannot encode negative big.Int"},
// uint256
{val: uint256.NewInt(0), output: "80"},
{val: uint256.NewInt(1), output: "01"},
{val: uint256.NewInt(127), output: "7F"},
{val: uint256.NewInt(128), output: "8180"},
{val: uint256.NewInt(256), output: "820100"},
{val: uint256.NewInt(1024), output: "820400"},
{val: uint256.NewInt(0xFFFFFF), output: "83FFFFFF"},
{val: uint256.NewInt(0xFFFFFFFF), output: "84FFFFFFFF"},
{val: uint256.NewInt(0xFFFFFFFFFF), output: "85FFFFFFFFFF"},
{val: uint256.NewInt(0xFFFFFFFFFFFF), output: "86FFFFFFFFFFFF"},
{val: uint256.NewInt(0xFFFFFFFFFFFFFF), output: "87FFFFFFFFFFFFFF"},
{
val: new(uint256.Int).SetBytes(unhex("102030405060708090A0B0C0D0E0F2")),
output: "8F102030405060708090A0B0C0D0E0F2",
},
{
val: new(uint256.Int).SetBytes(unhex("0100020003000400050006000700080009000A000B000C000D000E01")),
output: "9C0100020003000400050006000700080009000A000B000C000D000E01",
},
// non-pointer uint256.Int
{val: *uint256.NewInt(0), output: "80"},
{val: *uint256.NewInt(0xFFFFFF), output: "83FFFFFF"},
// byte arrays
{val: [0]byte{}, output: "80"},
{val: [1]byte{0}, output: "00"},
@ -256,6 +281,12 @@ var encTests = []encTest{
output: "F90200CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376CF84617364668471776572847A786376",
},
// Non-byte arrays are encoded as lists.
// Note that it is important to test [4]uint64 specifically,
// because that's the underlying type of uint256.Int.
{val: [4]uint32{1, 2, 3, 4}, output: "C401020304"},
{val: [4]uint64{1, 2, 3, 4}, output: "C401020304"},
// RawValue
{val: RawValue(unhex("01")), output: "01"},
{val: RawValue(unhex("82FFFF")), output: "82FFFF"},
@ -301,6 +332,7 @@ var encTests = []encTest{
{val: (*[]byte)(nil), output: "80"},
{val: (*[10]byte)(nil), output: "80"},
{val: (*big.Int)(nil), output: "80"},
{val: (*uint256.Int)(nil), output: "80"},
{val: (*[]string)(nil), output: "C0"},
{val: (*[10]string)(nil), output: "C0"},
{val: (*[]interface{})(nil), output: "C0"},
@ -509,6 +541,23 @@ func BenchmarkEncodeBigInts(b *testing.B) {
}
}
func BenchmarkEncodeU256Ints(b *testing.B) {
ints := make([]*uint256.Int, 200)
for i := range ints {
ints[i], _ = uint256.FromBig(math.BigPow(2, int64(i)))
}
out := bytes.NewBuffer(make([]byte, 0, 4096))
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
out.Reset()
if err := Encode(out, ints); err != nil {
b.Fatal(err)
}
}
}
func BenchmarkEncodeConcurrentInterface(b *testing.B) {
type struct1 struct {
A string

51
rlp/rlpgen/gen.go
View File

@ -283,7 +283,7 @@ func (op byteArrayOp) genDecode(ctx *genContext) (string, string) {
return resultV, b.String()
}
// bigIntNoPtrOp handles non-pointer big.Int.
// bigIntOp handles big.Int.
// This exists because big.Int has it's own decoder operation on rlp.Stream,
// but the decode method returns *big.Int, so it needs to be dereferenced.
type bigIntOp struct {
@ -330,6 +330,49 @@ func (op bigIntOp) genDecode(ctx *genContext) (string, string) {
return result, b.String()
}
// uint256Op handles "github.com/holiman/uint256".Int
type uint256Op struct {
pointer bool
}
func (op uint256Op) genWrite(ctx *genContext, v string) string {
var b bytes.Buffer
dst := v
if !op.pointer {
dst = "&" + v
}
fmt.Fprintf(&b, "w.WriteUint256(%s)\n", dst)
// Wrap with nil check.
if op.pointer {
code := b.String()
b.Reset()
fmt.Fprintf(&b, "if %s == nil {\n", v)
fmt.Fprintf(&b, " w.Write(rlp.EmptyString)")
fmt.Fprintf(&b, "} else {\n")
fmt.Fprint(&b, code)
fmt.Fprintf(&b, "}\n")
}
return b.String()
}
func (op uint256Op) genDecode(ctx *genContext) (string, string) {
ctx.addImport("github.com/holiman/uint256")
var b bytes.Buffer
resultV := ctx.temp()
fmt.Fprintf(&b, "var %s uint256.Int\n", resultV)
fmt.Fprintf(&b, "if err := dec.ReadUint256(&%s); err != nil { return err }\n", resultV)
result := resultV
if op.pointer {
result = "&" + resultV
}
return result, b.String()
}
// encoderDecoderOp handles rlp.Encoder and rlp.Decoder.
// In order to be used with this, the type must implement both interfaces.
// This restriction may be lifted in the future by creating separate ops for
@ -635,6 +678,9 @@ func (bctx *buildContext) makeOp(name *types.Named, typ types.Type, tags rlpstru
if isBigInt(typ) {
return bigIntOp{}, nil
}
if isUint256(typ) {
return uint256Op{}, nil
}
if typ == bctx.rawValueType {
return bctx.makeRawValueOp(), nil
}
@ -647,6 +693,9 @@ func (bctx *buildContext) makeOp(name *types.Named, typ types.Type, tags rlpstru
if isBigInt(typ.Elem()) {
return bigIntOp{pointer: true}, nil
}
if isUint256(typ.Elem()) {
return uint256Op{pointer: true}, nil
}
// Encoder/Decoder interfaces.
if bctx.isEncoder(typ) {
if bctx.isDecoder(typ) {

2
rlp/rlpgen/gen_test.go
View File

@ -47,7 +47,7 @@ func init() {
}
}
var tests = []string{"uints", "nil", "rawvalue", "optional", "bigint"}
var tests = []string{"uints", "nil", "rawvalue", "optional", "bigint", "uint256"}
func TestOutput(t *testing.T) {
for _, test := range tests {

10
rlp/rlpgen/testdata/uint256.in.txt vendored Normal file
View File

@ -0,0 +1,10 @@
// -*- mode: go -*-
package test
import "github.com/holiman/uint256"
type Test struct {
Int *uint256.Int
IntNoPtr uint256.Int
}

44
rlp/rlpgen/testdata/uint256.out.txt vendored Normal file
View File

@ -0,0 +1,44 @@
package test
import "github.com/ethereum/go-ethereum/rlp"
import "github.com/holiman/uint256"
import "io"
func (obj *Test) EncodeRLP(_w io.Writer) error {
w := rlp.NewEncoderBuffer(_w)
_tmp0 := w.List()
if obj.Int == nil {
w.Write(rlp.EmptyString)
} else {
w.WriteUint256(obj.Int)
}
w.WriteUint256(&obj.IntNoPtr)
w.ListEnd(_tmp0)
return w.Flush()
}
func (obj *Test) DecodeRLP(dec *rlp.Stream) error {
var _tmp0 Test
{
if _, err := dec.List(); err != nil {
return err
}
// Int:
var _tmp1 uint256.Int
if err := dec.ReadUint256(&_tmp1); err != nil {
return err
}
_tmp0.Int = &_tmp1
// IntNoPtr:
var _tmp2 uint256.Int
if err := dec.ReadUint256(&_tmp2); err != nil {
return err
}
_tmp0.IntNoPtr = _tmp2
if err := dec.ListEnd(); err != nil {
return err
}
}
*obj = _tmp0
return nil
}

10
rlp/rlpgen/types.go
View File

@ -97,6 +97,16 @@ func isBigInt(typ types.Type) bool {
return name.Pkg().Path() == "math/big" && name.Name() == "Int"
}
// isUint256 checks whether 'typ' is "github.com/holiman/uint256".Int.
func isUint256(typ types.Type) bool {
named, ok := typ.(*types.Named)
if !ok {
return false
}
name := named.Obj()
return name.Pkg().Path() == "github.com/holiman/uint256" && name.Name() == "Int"
}
// isByte checks whether the underlying type of 'typ' is uint8.
func isByte(typ types.Type) bool {
basic, ok := resolveUnderlying(typ).(*types.Basic)