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unpack.go
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unpack.go
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package abi
import (
"encoding/binary"
"fmt"
"math/big"
"reflect"
"github.com/ligo-ai/ligo-chain/common"
)
var (
MaxUint256 = big.NewInt(0).Add(
big.NewInt(0).Exp(big.NewInt(2), big.NewInt(256), nil),
big.NewInt(-1))
MaxInt256 = big.NewInt(0).Add(
big.NewInt(0).Exp(big.NewInt(2), big.NewInt(255), nil),
big.NewInt(-1))
)
func ReadInteger(typ byte, kind reflect.Kind, b []byte) interface{} {
switch kind {
case reflect.Uint8:
return b[len(b)-1]
case reflect.Uint16:
return binary.BigEndian.Uint16(b[len(b)-2:])
case reflect.Uint32:
return binary.BigEndian.Uint32(b[len(b)-4:])
case reflect.Uint64:
return binary.BigEndian.Uint64(b[len(b)-8:])
case reflect.Int8:
return int8(b[len(b)-1])
case reflect.Int16:
return int16(binary.BigEndian.Uint16(b[len(b)-2:]))
case reflect.Int32:
return int32(binary.BigEndian.Uint32(b[len(b)-4:]))
case reflect.Int64:
return int64(binary.BigEndian.Uint64(b[len(b)-8:]))
default:
ret := new(big.Int).SetBytes(b)
if typ == UintTy {
return ret
}
if ret.Cmp(MaxInt256) > 0 {
ret.Add(MaxUint256, big.NewInt(0).Neg(ret))
ret.Add(ret, big.NewInt(1))
ret.Neg(ret)
}
return ret
}
}
func readBool(word []byte) (bool, error) {
for _, b := range word[:31] {
if b != 0 {
return false, errBadBool
}
}
switch word[31] {
case 0:
return false, nil
case 1:
return true, nil
default:
return false, errBadBool
}
}
func readFunctionType(t Type, word []byte) (funcTy [24]byte, err error) {
if t.T != FunctionTy {
return [24]byte{}, fmt.Errorf("abi: invalid type in call to make function type byte array")
}
if garbage := binary.BigEndian.Uint64(word[24:32]); garbage != 0 {
err = fmt.Errorf("abi: got improperly encoded function type, got %v", word)
} else {
copy(funcTy[:], word[0:24])
}
return
}
func ReadFixedBytes(t Type, word []byte) (interface{}, error) {
if t.T != FixedBytesTy {
return nil, fmt.Errorf("abi: invalid type in call to make fixed byte array")
}
array := reflect.New(t.Type).Elem()
reflect.Copy(array, reflect.ValueOf(word[0:t.Size]))
return array.Interface(), nil
}
func forEachUnpack(t Type, output []byte, start, size int) (interface{}, error) {
if size < 0 {
return nil, fmt.Errorf("cannot marshal input to array, size is negative (%d)", size)
}
if start+32*size > len(output) {
return nil, fmt.Errorf("abi: cannot marshal in to go array: offset %d would go over slice boundary (len=%d)", len(output), start+32*size)
}
var refSlice reflect.Value
if t.T == SliceTy {
refSlice = reflect.MakeSlice(t.Type, size, size)
} else if t.T == ArrayTy {
refSlice = reflect.New(t.Type).Elem()
} else {
return nil, fmt.Errorf("abi: invalid type in array/slice unpacking stage")
}
elemSize := getTypeSize(*t.Elem)
for i, j := start, 0; j < size; i, j = i+elemSize, j+1 {
inter, err := toGoType(i, *t.Elem, output)
if err != nil {
return nil, err
}
refSlice.Index(j).Set(reflect.ValueOf(inter))
}
return refSlice.Interface(), nil
}
func forTupleUnpack(t Type, output []byte) (interface{}, error) {
retval := reflect.New(t.Type).Elem()
virtualArgs := 0
for index, elem := range t.TupleElems {
marshalledValue, err := toGoType((index+virtualArgs)*32, *elem, output)
if elem.T == ArrayTy && !isDynamicType(*elem) {
virtualArgs += getTypeSize(*elem)/32 - 1
} else if elem.T == TupleTy && !isDynamicType(*elem) {
virtualArgs += getTypeSize(*elem)/32 - 1
}
if err != nil {
return nil, err
}
retval.Field(index).Set(reflect.ValueOf(marshalledValue))
}
return retval.Interface(), nil
}
func toGoType(index int, t Type, output []byte) (interface{}, error) {
if index+32 > len(output) {
return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), index+32)
}
var (
returnOutput []byte
begin, length int
err error
)
if t.requiresLengthPrefix() {
begin, length, err = lengthPrefixPointsTo(index, output)
if err != nil {
return nil, err
}
} else {
returnOutput = output[index : index+32]
}
switch t.T {
case TupleTy:
if isDynamicType(t) {
begin, err := tuplePointsTo(index, output)
if err != nil {
return nil, err
}
return forTupleUnpack(t, output[begin:])
} else {
return forTupleUnpack(t, output[index:])
}
case SliceTy:
return forEachUnpack(t, output[begin:], 0, length)
case ArrayTy:
if isDynamicType(*t.Elem) {
offset := int64(binary.BigEndian.Uint64(returnOutput[len(returnOutput)-8:]))
return forEachUnpack(t, output[offset:], 0, t.Size)
}
return forEachUnpack(t, output[index:], 0, t.Size)
case StringTy:
return string(output[begin : begin+length]), nil
case IntTy, UintTy:
return ReadInteger(t.T, t.Kind, returnOutput), nil
case BoolTy:
return readBool(returnOutput)
case AddressTy:
return common.BytesToAddress(returnOutput), nil
case HashTy:
return common.BytesToHash(returnOutput), nil
case BytesTy:
return output[begin : begin+length], nil
case FixedBytesTy:
return ReadFixedBytes(t, returnOutput)
case FunctionTy:
return readFunctionType(t, returnOutput)
default:
return nil, fmt.Errorf("abi: unknown type %v", t.T)
}
}
func lengthPrefixPointsTo(index int, output []byte) (start int, length int, err error) {
bigOffsetEnd := big.NewInt(0).SetBytes(output[index : index+32])
bigOffsetEnd.Add(bigOffsetEnd, common.Big32)
outputLength := big.NewInt(int64(len(output)))
if bigOffsetEnd.Cmp(outputLength) > 0 {
return 0, 0, fmt.Errorf("abi: cannot marshal in to go slice: offset %v would go over slice boundary (len=%v)", bigOffsetEnd, outputLength)
}
if bigOffsetEnd.BitLen() > 63 {
return 0, 0, fmt.Errorf("abi offset larger than int64: %v", bigOffsetEnd)
}
offsetEnd := int(bigOffsetEnd.Uint64())
lengthBig := big.NewInt(0).SetBytes(output[offsetEnd-32 : offsetEnd])
totalSize := big.NewInt(0)
totalSize.Add(totalSize, bigOffsetEnd)
totalSize.Add(totalSize, lengthBig)
if totalSize.BitLen() > 63 {
return 0, 0, fmt.Errorf("abi: length larger than int64: %v", totalSize)
}
if totalSize.Cmp(outputLength) > 0 {
return 0, 0, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %v require %v", outputLength, totalSize)
}
start = int(bigOffsetEnd.Uint64())
length = int(lengthBig.Uint64())
return
}
func tuplePointsTo(index int, output []byte) (start int, err error) {
offset := big.NewInt(0).SetBytes(output[index : index+32])
outputLen := big.NewInt(int64(len(output)))
if offset.Cmp(big.NewInt(int64(len(output)))) > 0 {
return 0, fmt.Errorf("abi: cannot marshal in to go slice: offset %v would go over slice boundary (len=%v)", offset, outputLen)
}
if offset.BitLen() > 63 {
return 0, fmt.Errorf("abi offset larger than int64: %v", offset)
}
return int(offset.Uint64()), nil
}