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decode.go
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decode.go
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package abi
import (
"fmt"
"math/big"
"github.com/defiweb/go-eth/types"
)
// DecodeValue decodes the given ABI-encoded data into the given value.
// Value must be a pointer to a struct or a map.
func DecodeValue(t Type, abi []byte, val any) error {
return Default.DecodeValue(t, abi, val)
}
// MustDecodeValue is like DecodeValue but panics on error.
func MustDecodeValue(t Type, abi []byte, val any) {
Default.MustDecodeValue(t, abi, val)
}
// DecodeValues decodes the given ABI-encoded data into the given values.
// The t type must be a tuple type.
func DecodeValues(t Type, abi []byte, vals ...any) error {
return Default.DecodeValues(t, abi, vals...)
}
// MustDecodeValues is like DecodeValues but panics on error.
func MustDecodeValues(t Type, abi []byte, vals ...any) {
Default.MustDecodeValues(t, abi, vals...)
}
// DecodeValue decodes the given ABI-encoded data into the given value.
// Value must be a pointer to a struct or a map.
func (a *ABI) DecodeValue(t Type, abi []byte, val any) error {
v := t.Value()
if _, err := v.DecodeABI(BytesToWords(abi)); err != nil {
return err
}
return a.Mapper.Map(v, val)
}
// MustDecodeValue is like DecodeValue but panics on error.
func (a *ABI) MustDecodeValue(t Type, abi []byte, val any) {
if err := a.DecodeValue(t, abi, val); err != nil {
panic(err)
}
}
// DecodeValues decodes the given ABI-encoded data into the given values.
// The t type must be a tuple type.
func (a *ABI) DecodeValues(t Type, abi []byte, vals ...any) error {
v, ok := t.Value().(*TupleValue)
if !ok {
return fmt.Errorf("abi: cannot decode values, expected tuple type")
}
if len(*v) != len(vals) {
return fmt.Errorf("abi: cannot decode tuple, expected %d values, got %d", len(*v), len(vals))
}
if _, err := v.DecodeABI(BytesToWords(abi)); err != nil {
return err
}
for i, elem := range *v {
if vals[i] == nil {
continue // Nil values are ignored.
}
if err := a.Mapper.Map(elem.Value, vals[i]); err != nil {
return err
}
}
return nil
}
// MustDecodeValues is like DecodeValues but panics on error.
func (a *ABI) MustDecodeValues(t Type, abi []byte, vals ...any) {
if err := a.DecodeValues(t, abi, vals...); err != nil {
panic(err)
}
}
// decodeTuple decodes a tuple from the given words and stores the result in the
// given tuple. The tuple must contain the correct number of elements.
func decodeTuple(t *[]Value, w Words) (int, error) {
var (
wordIdx int
wordsRead int
)
for _, e := range *t {
if wordIdx >= len(w) {
return 0, fmt.Errorf("abi: cannot decode tuple, unexpected end of data")
}
if e.IsDynamic() {
offset, err := readInt(&w[wordIdx])
if err != nil {
return 0, fmt.Errorf("abi: cannot decode tuple, invalid offset: %v", err)
}
if offset%WordLength != 0 {
return 0, fmt.Errorf("abi: cannot decode tuple, offset not a multiple of word length")
}
wordOffset := offset / WordLength
if wordOffset >= len(w) {
return 0, fmt.Errorf("abi: cannot decode tuple, offset exceeds data length")
}
n, err := e.DecodeABI(w[wordOffset:])
if err != nil {
return 0, err
}
wordIdx++
if wordOffset+n > wordsRead {
wordsRead = wordOffset + n
}
} else {
n, err := e.DecodeABI(w[wordIdx:])
if err != nil {
return 0, err
}
wordIdx += n
if wordIdx > wordsRead {
wordsRead = wordIdx
}
}
}
return wordsRead, nil
}
// decodeArray decodes a dynamic array from the given words and stores the result
// in the given array. The elements of the array are decoded to t type.
func decodeArray(a *[]Value, w Words, t Type) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode array from empty data")
}
size, err := readInt(&w[0])
if err != nil {
return 0, err
}
if size+1 > len(w) {
return 0, fmt.Errorf("abi: cannot decode array, size exceeds data length")
}
*a = make([]Value, size)
for i := 0; i < size; i++ {
(*a)[i] = t.Value()
}
if _, err := decodeTuple(a, w[1:]); err != nil {
return 0, err
}
return size + 1, nil
}
// decodeFixedArray decodes a fixed array from the given words into the values
// in the given array.
func decodeFixedArray(a *[]Value, w Words) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode array[%d] from empty data", len(*a))
}
if _, err := decodeTuple(a, w); err != nil {
return 0, err
}
return len(*a), nil
}
// decodeBytes decodes a dynamic byte array from the given words and stores the
// result in the given byte array.
func decodeBytes(b *[]byte, w Words) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode bytes from empty data")
}
size, err := readInt(&w[0])
if err != nil {
return 0, err
}
l := requiredWords(size)
if l+1 > len(w) {
return 0, fmt.Errorf("abi: cannot decode bytes, size exceeds data length")
}
*b = w[1 : l+1].Bytes()[0:size]
return size + 1, nil
}
// decodeFixedBytes decodes a fixed byte of the given size from the given words
// and stores the result in the given byte array.
func decodeFixedBytes(b *[]byte, w Words, size int) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode bytes%d from empty data", size)
}
if len(*b) != size {
return 0, fmt.Errorf("abi: cannot decode bytes%d, expected %d bytes, got %d", size, size, len(*b))
}
copy(*b, w[0].Bytes()[0:size])
return 1, nil
}
// decodeInt decodes an integer of the given size from the given words and
// stores the result in the given integer. If the integer is larger than the
// maximum value for the given size, an error is returned.
func decodeInt(v *big.Int, w Words, size int) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode int from empty data")
}
if size%8 != 0 {
return 0, fmt.Errorf("abi: cannot decode int, size not a multiple of 8")
}
b := w[0].Bytes()[WordLength-size/8:]
x := newIntX(size)
if err := x.SetBytes(b); err != nil {
return 0, err
}
v.Set(x.BigInt())
return 1, nil
}
// decodeUint decodes an unsigned integer of the given size from the given
// words and stores the result in the given integer. If the integer is larger
// than the maximum value for the given size, an error is returned.
func decodeUint(v *big.Int, w Words, size int) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode int from empty data")
}
if size%8 != 0 {
return 0, fmt.Errorf("abi: cannot decode int, size not a multiple of 8")
}
b := w[0].Bytes()[WordLength-size/8:]
x := newUintX(size)
if err := x.SetBytes(b); err != nil {
return 0, err
}
v.Set(x.BigInt())
return 1, nil
}
// decodeBool decodes a boolean from the given words and stores the result in
// the given boolean.
func decodeBool(a *bool, w Words) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode bool from empty data")
}
*a = !w[0].IsZero()
return 1, nil
}
// decodeAddress decodes an address from the given words and stores the result
// in the given address.
func decodeAddress(v *types.Address, w Words) (int, error) {
if len(w) == 0 {
return 0, fmt.Errorf("abi: cannot decode address from empty data")
}
*v = types.MustAddressFromBytes(w[0].Bytes()[WordLength-types.AddressLength:])
return 1, nil
}
// readInt reads an integer from the given word.
func readInt(w *Word) (int, error) {
i32 := newIntX(32)
if err := i32.SetBytes(w.Bytes()); err != nil {
return 0, err
}
return i32.Int()
}