2014-11-13 11:31:48 -08:00
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package rlp
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import (
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2014-11-24 10:01:25 -08:00
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"bufio"
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"math/big"
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"reflect"
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)
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var (
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errNoPointer = errors.New("rlp: interface given to Decode must be a pointer")
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errDecodeIntoNil = errors.New("rlp: pointer given to Decode must not be nil")
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)
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// Decoder is implemented by types that require custom RLP
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// decoding rules or need to decode into private fields.
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//
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// The DecodeRLP method should read one value from the given
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// Stream. It is not forbidden to read less or more, but it might
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// be confusing.
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type Decoder interface {
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DecodeRLP(*Stream) error
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}
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// Decode parses RLP-encoded data from r and stores the result in the
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// value pointed to by val. Val must be a non-nil pointer. If r does
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// not implement ByteReader, Decode will do its own buffering.
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//
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// Decode uses the following type-dependent decoding rules:
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//
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// If the type implements the Decoder interface, decode calls
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// DecodeRLP.
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//
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// To decode into a pointer, Decode will set the pointer to nil if the
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// input has size zero or the input is a single byte with value zero.
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// If the input has nonzero size, Decode will allocate a new value of
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// the type being pointed to.
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//
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// To decode into a struct, Decode expects the input to be an RLP
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// list. The decoded elements of the list are assigned to each public
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// field in the order given by the struct's definition. If the input
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// list has too few elements, no error is returned and the remaining
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// fields will have the zero value.
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// Recursive struct types are supported.
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//
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// To decode into a slice, the input must be a list and the resulting
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// slice will contain the input elements in order.
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// As a special case, if the slice has a byte-size element type, the input
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// can also be an RLP string.
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//
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// To decode into a Go string, the input must be an RLP string. The
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// bytes are taken as-is and will not necessarily be valid UTF-8.
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//
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// To decode into an unsigned integer type, the input must also be an RLP
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// string. The bytes are interpreted as a big endian representation of
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// the integer. If the RLP string is larger than the bit size of the
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// type, Decode will return an error. Decode also supports *big.Int.
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// There is no size limit for big integers.
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//
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// To decode into an interface value, Decode stores one of these
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// in the value:
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//
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// []interface{}, for RLP lists
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// []byte, for RLP strings
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//
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// Non-empty interface types are not supported, nor are booleans,
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// signed integers, floating point numbers, maps, channels and
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// functions.
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func Decode(r io.Reader, val interface{}) error {
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return NewStream(r).Decode(val)
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}
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2014-11-25 07:00:48 -08:00
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type decodeError struct {
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msg string
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typ reflect.Type
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ctx []string
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}
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func (err *decodeError) Error() string {
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ctx := ""
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if len(err.ctx) > 0 {
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ctx = ", decoding into "
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for i := len(err.ctx) - 1; i >= 0; i-- {
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ctx += err.ctx[i]
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}
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}
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return fmt.Sprintf("rlp: %s for %v%s", err.msg, err.typ, ctx)
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}
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func wrapStreamError(err error, typ reflect.Type) error {
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switch err {
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case ErrExpectedList:
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return &decodeError{msg: "expected input list", typ: typ}
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case ErrExpectedString:
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return &decodeError{msg: "expected input string or byte", typ: typ}
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case errUintOverflow:
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return &decodeError{msg: "input string too long", typ: typ}
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case errNotAtEOL:
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return &decodeError{msg: "input list has too many elements", typ: typ}
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}
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return err
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}
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func addErrorContext(err error, ctx string) error {
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if decErr, ok := err.(*decodeError); ok {
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decErr.ctx = append(decErr.ctx, ctx)
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}
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return err
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}
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2014-12-09 01:39:39 -08:00
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var (
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decoderInterface = reflect.TypeOf(new(Decoder)).Elem()
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bigInt = reflect.TypeOf(big.Int{})
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)
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func makeDecoder(typ reflect.Type) (dec decoder, err error) {
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kind := typ.Kind()
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switch {
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case typ.Implements(decoderInterface):
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return decodeDecoder, nil
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case kind != reflect.Ptr && reflect.PtrTo(typ).Implements(decoderInterface):
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return decodeDecoderNoPtr, nil
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case typ.AssignableTo(reflect.PtrTo(bigInt)):
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return decodeBigInt, nil
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case typ.AssignableTo(bigInt):
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return decodeBigIntNoPtr, nil
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case isUint(kind):
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return decodeUint, nil
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case kind == reflect.String:
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return decodeString, nil
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case kind == reflect.Slice || kind == reflect.Array:
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return makeListDecoder(typ)
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case kind == reflect.Struct:
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return makeStructDecoder(typ)
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case kind == reflect.Ptr:
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return makePtrDecoder(typ)
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case kind == reflect.Interface && typ.NumMethod() == 0:
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return decodeInterface, nil
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default:
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return nil, fmt.Errorf("rlp: type %v is not RLP-serializable", typ)
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}
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}
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func decodeUint(s *Stream, val reflect.Value) error {
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typ := val.Type()
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num, err := s.uint(typ.Bits())
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if err != nil {
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return wrapStreamError(err, val.Type())
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}
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val.SetUint(num)
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return nil
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}
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func decodeString(s *Stream, val reflect.Value) error {
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b, err := s.Bytes()
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if err != nil {
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return wrapStreamError(err, val.Type())
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}
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val.SetString(string(b))
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return nil
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}
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func decodeBigIntNoPtr(s *Stream, val reflect.Value) error {
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return decodeBigInt(s, val.Addr())
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}
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func decodeBigInt(s *Stream, val reflect.Value) error {
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b, err := s.Bytes()
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if err != nil {
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return wrapStreamError(err, val.Type())
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}
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i := val.Interface().(*big.Int)
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if i == nil {
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i = new(big.Int)
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val.Set(reflect.ValueOf(i))
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}
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i.SetBytes(b)
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return nil
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}
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func makeListDecoder(typ reflect.Type) (decoder, error) {
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etype := typ.Elem()
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if etype.Kind() == reflect.Uint8 && !reflect.PtrTo(etype).Implements(decoderInterface) {
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if typ.Kind() == reflect.Array {
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return decodeByteArray, nil
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} else {
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return decodeByteSlice, nil
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}
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}
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etypeinfo, err := cachedTypeInfo1(etype)
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if err != nil {
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return nil, err
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}
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isArray := typ.Kind() == reflect.Array
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return func(s *Stream, val reflect.Value) error {
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if isArray {
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return decodeListArray(s, val, etypeinfo.decoder)
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} else {
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return decodeListSlice(s, val, etypeinfo.decoder)
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}
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}, nil
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}
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2014-12-09 01:44:48 -08:00
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func decodeListSlice(s *Stream, val reflect.Value, elemdec decoder) error {
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size, err := s.List()
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if err != nil {
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return wrapStreamError(err, val.Type())
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}
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if size == 0 {
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val.Set(reflect.MakeSlice(val.Type(), 0, 0))
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return s.ListEnd()
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}
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i := 0
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for ; ; i++ {
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// grow slice if necessary
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if i >= val.Cap() {
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newcap := val.Cap() + val.Cap()/2
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if newcap < 4 {
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newcap = 4
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}
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newv := reflect.MakeSlice(val.Type(), val.Len(), newcap)
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reflect.Copy(newv, val)
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val.Set(newv)
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}
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if i >= val.Len() {
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val.SetLen(i + 1)
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}
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// decode into element
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if err := elemdec(s, val.Index(i)); err == EOL {
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break
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} else if err != nil {
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return addErrorContext(err, fmt.Sprint("[", i, "]"))
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}
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}
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if i < val.Len() {
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val.SetLen(i)
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}
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return s.ListEnd()
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}
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2014-12-09 01:44:48 -08:00
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func decodeListArray(s *Stream, val reflect.Value, elemdec decoder) error {
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size, err := s.List()
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if err != nil {
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return err
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}
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if size == 0 {
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zero(val, 0)
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return s.ListEnd()
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}
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// The approach here is stolen from package json, although we differ
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// in the semantics for arrays. package json discards remaining
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// elements that would not fit into the array. We generate an error in
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// this case because we'd be losing information.
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vlen := val.Len()
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i := 0
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for ; i < vlen; i++ {
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if err := elemdec(s, val.Index(i)); err == EOL {
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break
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} else if err != nil {
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return addErrorContext(err, fmt.Sprint("[", i, "]"))
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}
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}
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if i < vlen {
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zero(val, i)
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}
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return wrapStreamError(s.ListEnd(), val.Type())
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}
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2014-11-13 11:31:48 -08:00
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func decodeByteSlice(s *Stream, val reflect.Value) error {
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kind, _, err := s.Kind()
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if err != nil {
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return err
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}
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if kind == List {
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return decodeListSlice(s, val, decodeUint)
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}
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b, err := s.Bytes()
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if err == nil {
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val.SetBytes(b)
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}
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return err
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}
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func decodeByteArray(s *Stream, val reflect.Value) error {
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kind, size, err := s.Kind()
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if err != nil {
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return err
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}
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switch kind {
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case Byte:
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if val.Len() == 0 {
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return &decodeError{msg: "input string too long", typ: val.Type()}
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}
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bv, _ := s.Uint()
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val.Index(0).SetUint(bv)
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zero(val, 1)
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case String:
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if uint64(val.Len()) < size {
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return &decodeError{msg: "input string too long", typ: val.Type()}
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}
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slice := val.Slice(0, int(size)).Interface().([]byte)
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if err := s.readFull(slice); err != nil {
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return err
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}
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zero(val, int(size))
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case List:
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return decodeListArray(s, val, decodeUint)
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}
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return nil
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}
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func zero(val reflect.Value, start int) {
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z := reflect.Zero(val.Type().Elem())
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end := val.Len()
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for i := start; i < end; i++ {
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val.Index(i).Set(z)
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}
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}
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type field struct {
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index int
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info *typeinfo
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}
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func makeStructDecoder(typ reflect.Type) (decoder, error) {
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var fields []field
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for i := 0; i < typ.NumField(); i++ {
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if f := typ.Field(i); f.PkgPath == "" { // exported
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info, err := cachedTypeInfo1(f.Type)
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if err != nil {
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|
|
return nil, err
|
|
|
|
}
|
|
|
|
fields = append(fields, field{i, info})
|
|
|
|
}
|
|
|
|
}
|
|
|
|
dec := func(s *Stream, val reflect.Value) (err error) {
|
|
|
|
if _, err = s.List(); err != nil {
|
2014-12-09 04:55:47 -08:00
|
|
|
return wrapStreamError(err, typ)
|
2014-11-13 11:31:48 -08:00
|
|
|
}
|
|
|
|
for _, f := range fields {
|
|
|
|
err = f.info.decoder(s, val.Field(f.index))
|
|
|
|
if err == EOL {
|
|
|
|
// too few elements. leave the rest at their zero value.
|
|
|
|
break
|
|
|
|
} else if err != nil {
|
2015-01-05 08:10:42 -08:00
|
|
|
return addErrorContext(err, "."+typ.Field(f.index).Name)
|
2014-11-13 11:31:48 -08:00
|
|
|
}
|
|
|
|
}
|
2014-12-09 04:55:47 -08:00
|
|
|
return wrapStreamError(s.ListEnd(), typ)
|
2014-11-13 11:31:48 -08:00
|
|
|
}
|
|
|
|
return dec, nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func makePtrDecoder(typ reflect.Type) (decoder, error) {
|
|
|
|
etype := typ.Elem()
|
|
|
|
etypeinfo, err := cachedTypeInfo1(etype)
|
|
|
|
if err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
|
|
|
dec := func(s *Stream, val reflect.Value) (err error) {
|
|
|
|
_, size, err := s.Kind()
|
|
|
|
if err != nil || size == 0 && s.byteval == 0 {
|
2014-11-17 03:02:08 -08:00
|
|
|
val.Set(reflect.Zero(typ)) // set to nil
|
2014-11-13 11:31:48 -08:00
|
|
|
return err
|
|
|
|
}
|
|
|
|
newval := val
|
|
|
|
if val.IsNil() {
|
|
|
|
newval = reflect.New(etype)
|
|
|
|
}
|
|
|
|
if err = etypeinfo.decoder(s, newval.Elem()); err == nil {
|
|
|
|
val.Set(newval)
|
|
|
|
}
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
return dec, nil
|
|
|
|
}
|
|
|
|
|
|
|
|
var ifsliceType = reflect.TypeOf([]interface{}{})
|
|
|
|
|
|
|
|
func decodeInterface(s *Stream, val reflect.Value) error {
|
|
|
|
kind, _, err := s.Kind()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if kind == List {
|
|
|
|
slice := reflect.New(ifsliceType).Elem()
|
2014-12-09 01:44:48 -08:00
|
|
|
if err := decodeListSlice(s, slice, decodeInterface); err != nil {
|
2014-11-13 11:31:48 -08:00
|
|
|
return err
|
|
|
|
}
|
|
|
|
val.Set(slice)
|
|
|
|
} else {
|
|
|
|
b, err := s.Bytes()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
val.Set(reflect.ValueOf(b))
|
|
|
|
}
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// This decoder is used for non-pointer values of types
|
|
|
|
// that implement the Decoder interface using a pointer receiver.
|
|
|
|
func decodeDecoderNoPtr(s *Stream, val reflect.Value) error {
|
|
|
|
return val.Addr().Interface().(Decoder).DecodeRLP(s)
|
|
|
|
}
|
|
|
|
|
|
|
|
func decodeDecoder(s *Stream, val reflect.Value) error {
|
|
|
|
// Decoder instances are not handled using the pointer rule if the type
|
|
|
|
// implements Decoder with pointer receiver (i.e. always)
|
|
|
|
// because it might handle empty values specially.
|
|
|
|
// We need to allocate one here in this case, like makePtrDecoder does.
|
|
|
|
if val.Kind() == reflect.Ptr && val.IsNil() {
|
|
|
|
val.Set(reflect.New(val.Type().Elem()))
|
|
|
|
}
|
|
|
|
return val.Interface().(Decoder).DecodeRLP(s)
|
|
|
|
}
|
|
|
|
|
|
|
|
// Kind represents the kind of value contained in an RLP stream.
|
|
|
|
type Kind int
|
|
|
|
|
|
|
|
const (
|
|
|
|
Byte Kind = iota
|
|
|
|
String
|
|
|
|
List
|
|
|
|
)
|
|
|
|
|
|
|
|
func (k Kind) String() string {
|
|
|
|
switch k {
|
|
|
|
case Byte:
|
|
|
|
return "Byte"
|
|
|
|
case String:
|
|
|
|
return "String"
|
|
|
|
case List:
|
|
|
|
return "List"
|
|
|
|
default:
|
|
|
|
return fmt.Sprintf("Unknown(%d)", k)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
var (
|
|
|
|
// EOL is returned when the end of the current list
|
|
|
|
// has been reached during streaming.
|
|
|
|
EOL = errors.New("rlp: end of list")
|
|
|
|
|
|
|
|
// Other errors
|
|
|
|
ErrExpectedString = errors.New("rlp: expected String or Byte")
|
|
|
|
ErrExpectedList = errors.New("rlp: expected List")
|
|
|
|
ErrElemTooLarge = errors.New("rlp: element is larger than containing list")
|
|
|
|
|
|
|
|
// internal errors
|
|
|
|
errNotInList = errors.New("rlp: call of ListEnd outside of any list")
|
|
|
|
errNotAtEOL = errors.New("rlp: call of ListEnd not positioned at EOL")
|
|
|
|
)
|
|
|
|
|
|
|
|
// ByteReader must be implemented by any input reader for a Stream. It
|
|
|
|
// is implemented by e.g. bufio.Reader and bytes.Reader.
|
|
|
|
type ByteReader interface {
|
|
|
|
io.Reader
|
|
|
|
io.ByteReader
|
|
|
|
}
|
|
|
|
|
|
|
|
// Stream can be used for piecemeal decoding of an input stream. This
|
|
|
|
// is useful if the input is very large or if the decoding rules for a
|
|
|
|
// type depend on the input structure. Stream does not keep an
|
|
|
|
// internal buffer. After decoding a value, the input reader will be
|
|
|
|
// positioned just before the type information for the next value.
|
|
|
|
//
|
|
|
|
// When decoding a list and the input position reaches the declared
|
|
|
|
// length of the list, all operations will return error EOL.
|
|
|
|
// The end of the list must be acknowledged using ListEnd to continue
|
|
|
|
// reading the enclosing list.
|
|
|
|
//
|
|
|
|
// Stream is not safe for concurrent use.
|
|
|
|
type Stream struct {
|
|
|
|
r ByteReader
|
|
|
|
uintbuf []byte
|
|
|
|
|
|
|
|
kind Kind // kind of value ahead
|
|
|
|
size uint64 // size of value ahead
|
|
|
|
byteval byte // value of single byte in type tag
|
|
|
|
stack []listpos
|
|
|
|
}
|
|
|
|
|
|
|
|
type listpos struct{ pos, size uint64 }
|
|
|
|
|
2014-11-24 10:01:25 -08:00
|
|
|
// NewStream creates a new stream reading from r.
|
|
|
|
// If r does not implement ByteReader, the Stream will
|
|
|
|
// introduce its own buffering.
|
|
|
|
func NewStream(r io.Reader) *Stream {
|
|
|
|
s := new(Stream)
|
|
|
|
s.Reset(r)
|
|
|
|
return s
|
|
|
|
}
|
2014-11-24 10:02:04 -08:00
|
|
|
|
|
|
|
// NewListStream creates a new stream that pretends to be positioned
|
|
|
|
// at an encoded list of the given length.
|
|
|
|
func NewListStream(r io.Reader, len uint64) *Stream {
|
|
|
|
s := new(Stream)
|
|
|
|
s.Reset(r)
|
|
|
|
s.kind = List
|
|
|
|
s.size = len
|
|
|
|
return s
|
2014-11-13 11:31:48 -08:00
|
|
|
}
|
|
|
|
|
|
|
|
// Bytes reads an RLP string and returns its contents as a byte slice.
|
|
|
|
// If the input does not contain an RLP string, the returned
|
|
|
|
// error will be ErrExpectedString.
|
|
|
|
func (s *Stream) Bytes() ([]byte, error) {
|
|
|
|
kind, size, err := s.Kind()
|
|
|
|
if err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
|
|
|
switch kind {
|
|
|
|
case Byte:
|
|
|
|
s.kind = -1 // rearm Kind
|
|
|
|
return []byte{s.byteval}, nil
|
|
|
|
case String:
|
|
|
|
b := make([]byte, size)
|
|
|
|
if err = s.readFull(b); err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
|
|
|
return b, nil
|
|
|
|
default:
|
|
|
|
return nil, ErrExpectedString
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-11-25 07:00:48 -08:00
|
|
|
var errUintOverflow = errors.New("rlp: uint overflow")
|
|
|
|
|
2014-11-13 11:31:48 -08:00
|
|
|
// Uint reads an RLP string of up to 8 bytes and returns its contents
|
|
|
|
// as an unsigned integer. If the input does not contain an RLP string, the
|
|
|
|
// returned error will be ErrExpectedString.
|
|
|
|
func (s *Stream) Uint() (uint64, error) {
|
|
|
|
return s.uint(64)
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *Stream) uint(maxbits int) (uint64, error) {
|
|
|
|
kind, size, err := s.Kind()
|
|
|
|
if err != nil {
|
|
|
|
return 0, err
|
|
|
|
}
|
|
|
|
switch kind {
|
|
|
|
case Byte:
|
|
|
|
s.kind = -1 // rearm Kind
|
|
|
|
return uint64(s.byteval), nil
|
|
|
|
case String:
|
|
|
|
if size > uint64(maxbits/8) {
|
2014-11-25 07:00:48 -08:00
|
|
|
return 0, errUintOverflow
|
2014-11-13 11:31:48 -08:00
|
|
|
}
|
|
|
|
return s.readUint(byte(size))
|
|
|
|
default:
|
|
|
|
return 0, ErrExpectedString
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// List starts decoding an RLP list. If the input does not contain a
|
|
|
|
// list, the returned error will be ErrExpectedList. When the list's
|
|
|
|
// end has been reached, any Stream operation will return EOL.
|
|
|
|
func (s *Stream) List() (size uint64, err error) {
|
|
|
|
kind, size, err := s.Kind()
|
|
|
|
if err != nil {
|
|
|
|
return 0, err
|
|
|
|
}
|
|
|
|
if kind != List {
|
|
|
|
return 0, ErrExpectedList
|
|
|
|
}
|
|
|
|
s.stack = append(s.stack, listpos{0, size})
|
|
|
|
s.kind = -1
|
|
|
|
s.size = 0
|
|
|
|
return size, nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// ListEnd returns to the enclosing list.
|
|
|
|
// The input reader must be positioned at the end of a list.
|
|
|
|
func (s *Stream) ListEnd() error {
|
|
|
|
if len(s.stack) == 0 {
|
|
|
|
return errNotInList
|
|
|
|
}
|
|
|
|
tos := s.stack[len(s.stack)-1]
|
|
|
|
if tos.pos != tos.size {
|
|
|
|
return errNotAtEOL
|
|
|
|
}
|
|
|
|
s.stack = s.stack[:len(s.stack)-1] // pop
|
|
|
|
if len(s.stack) > 0 {
|
|
|
|
s.stack[len(s.stack)-1].pos += tos.size
|
|
|
|
}
|
|
|
|
s.kind = -1
|
|
|
|
s.size = 0
|
|
|
|
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.
|
|
|
|
func (s *Stream) Decode(val interface{}) error {
|
|
|
|
if val == nil {
|
|
|
|
return errDecodeIntoNil
|
|
|
|
}
|
|
|
|
rval := reflect.ValueOf(val)
|
|
|
|
rtyp := rval.Type()
|
|
|
|
if rtyp.Kind() != reflect.Ptr {
|
|
|
|
return errNoPointer
|
|
|
|
}
|
|
|
|
if rval.IsNil() {
|
|
|
|
return errDecodeIntoNil
|
|
|
|
}
|
|
|
|
info, err := cachedTypeInfo(rtyp.Elem())
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
2015-01-05 08:10:42 -08:00
|
|
|
|
|
|
|
err = info.decoder(s, rval.Elem())
|
|
|
|
if decErr, ok := err.(*decodeError); ok && len(decErr.ctx) > 0 {
|
|
|
|
// add decode target type to error so context has more meaning
|
|
|
|
decErr.ctx = append(decErr.ctx, fmt.Sprint("(", rtyp.Elem(), ")"))
|
|
|
|
}
|
|
|
|
return err
|
2014-11-13 11:31:48 -08:00
|
|
|
}
|
|
|
|
|
2014-11-24 10:01:25 -08:00
|
|
|
// Reset discards any information about the current decoding context
|
|
|
|
// and starts reading from r. If r does not also implement ByteReader,
|
|
|
|
// Stream will do its own buffering.
|
|
|
|
func (s *Stream) Reset(r io.Reader) {
|
|
|
|
bufr, ok := r.(ByteReader)
|
|
|
|
if !ok {
|
|
|
|
bufr = bufio.NewReader(r)
|
|
|
|
}
|
|
|
|
s.r = bufr
|
|
|
|
s.stack = s.stack[:0]
|
|
|
|
s.size = 0
|
|
|
|
s.kind = -1
|
|
|
|
if s.uintbuf == nil {
|
|
|
|
s.uintbuf = make([]byte, 8)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-11-13 11:31:48 -08:00
|
|
|
// Kind returns the kind and size of the next value in the
|
|
|
|
// input stream.
|
|
|
|
//
|
|
|
|
// The returned size is the number of bytes that make up the value.
|
|
|
|
// For kind == Byte, the size is zero because the value is
|
|
|
|
// contained in the type tag.
|
|
|
|
//
|
|
|
|
// The first call to Kind will read size information from the input
|
|
|
|
// reader and leave it positioned at the start of the actual bytes of
|
|
|
|
// the value. Subsequent calls to Kind (until the value is decoded)
|
|
|
|
// will not advance the input reader and return cached information.
|
|
|
|
func (s *Stream) Kind() (kind Kind, size uint64, err error) {
|
|
|
|
var tos *listpos
|
|
|
|
if len(s.stack) > 0 {
|
|
|
|
tos = &s.stack[len(s.stack)-1]
|
|
|
|
}
|
|
|
|
if s.kind < 0 {
|
|
|
|
if tos != nil && tos.pos == tos.size {
|
|
|
|
return 0, 0, EOL
|
|
|
|
}
|
|
|
|
kind, size, err = s.readKind()
|
|
|
|
if err != nil {
|
|
|
|
return 0, 0, err
|
|
|
|
}
|
|
|
|
s.kind, s.size = kind, size
|
|
|
|
}
|
|
|
|
if tos != nil && tos.pos+s.size > tos.size {
|
|
|
|
return 0, 0, ErrElemTooLarge
|
|
|
|
}
|
|
|
|
return s.kind, s.size, nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *Stream) readKind() (kind Kind, size uint64, err error) {
|
|
|
|
b, err := s.readByte()
|
|
|
|
if err != nil {
|
|
|
|
return 0, 0, err
|
|
|
|
}
|
|
|
|
s.byteval = 0
|
|
|
|
switch {
|
|
|
|
case b < 0x80:
|
|
|
|
// For a single byte whose value is in the [0x00, 0x7F] range, that byte
|
|
|
|
// is its own RLP encoding.
|
|
|
|
s.byteval = b
|
|
|
|
return Byte, 0, nil
|
|
|
|
case b < 0xB8:
|
|
|
|
// Otherwise, if a string is 0-55 bytes long,
|
|
|
|
// the RLP encoding consists of a single byte with value 0x80 plus the
|
|
|
|
// length of the string followed by the string. The range of the first
|
|
|
|
// byte is thus [0x80, 0xB7].
|
|
|
|
return String, uint64(b - 0x80), nil
|
|
|
|
case b < 0xC0:
|
|
|
|
// If a string is more than 55 bytes long, the
|
|
|
|
// RLP encoding consists of a single byte with value 0xB7 plus the length
|
|
|
|
// of the length of the string in binary form, followed by the length of
|
|
|
|
// the string, followed by the string. For example, a length-1024 string
|
|
|
|
// would be encoded as 0xB90400 followed by the string. The range of
|
|
|
|
// the first byte is thus [0xB8, 0xBF].
|
|
|
|
size, err = s.readUint(b - 0xB7)
|
|
|
|
return String, size, err
|
|
|
|
case b < 0xF8:
|
|
|
|
// If the total payload of a list
|
|
|
|
// (i.e. the combined length of all its items) is 0-55 bytes long, the
|
|
|
|
// RLP encoding consists of a single byte with value 0xC0 plus the length
|
|
|
|
// of the list followed by the concatenation of the RLP encodings of the
|
|
|
|
// items. The range of the first byte is thus [0xC0, 0xF7].
|
|
|
|
return List, uint64(b - 0xC0), nil
|
|
|
|
default:
|
|
|
|
// If the total payload of a list is more than 55 bytes long,
|
|
|
|
// the RLP encoding consists of a single byte with value 0xF7
|
|
|
|
// plus the length of the length of the payload in binary
|
|
|
|
// form, followed by the length of the payload, followed by
|
|
|
|
// the concatenation of the RLP encodings of the items. The
|
|
|
|
// range of the first byte is thus [0xF8, 0xFF].
|
|
|
|
size, err = s.readUint(b - 0xF7)
|
|
|
|
return List, size, err
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *Stream) readUint(size byte) (uint64, error) {
|
|
|
|
if size == 1 {
|
|
|
|
b, err := s.readByte()
|
|
|
|
if err == io.EOF {
|
|
|
|
err = io.ErrUnexpectedEOF
|
|
|
|
}
|
|
|
|
return uint64(b), err
|
|
|
|
}
|
|
|
|
start := int(8 - size)
|
|
|
|
for i := 0; i < start; i++ {
|
|
|
|
s.uintbuf[i] = 0
|
|
|
|
}
|
|
|
|
err := s.readFull(s.uintbuf[start:])
|
|
|
|
return binary.BigEndian.Uint64(s.uintbuf), err
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *Stream) readFull(buf []byte) (err error) {
|
|
|
|
s.willRead(uint64(len(buf)))
|
|
|
|
var nn, n int
|
|
|
|
for n < len(buf) && err == nil {
|
|
|
|
nn, err = s.r.Read(buf[n:])
|
|
|
|
n += nn
|
|
|
|
}
|
|
|
|
if err == io.EOF {
|
|
|
|
err = io.ErrUnexpectedEOF
|
|
|
|
}
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *Stream) readByte() (byte, error) {
|
|
|
|
s.willRead(1)
|
|
|
|
b, err := s.r.ReadByte()
|
|
|
|
if len(s.stack) > 0 && err == io.EOF {
|
|
|
|
err = io.ErrUnexpectedEOF
|
|
|
|
}
|
|
|
|
return b, err
|
|
|
|
}
|
|
|
|
|
|
|
|
func (s *Stream) willRead(n uint64) {
|
|
|
|
s.kind = -1 // rearm Kind
|
|
|
|
if len(s.stack) > 0 {
|
|
|
|
s.stack[len(s.stack)-1].pos += n
|
|
|
|
}
|
|
|
|
}
|