util: add 'constructors' for BinReader/BinWriter

And an additional BufBinWriter to ease buffer management.

pkg/core/account_state.go

@@ -68,7 +68,7 @@ func NewAccountState(scriptHash util.Uint160) *AccountState {
 
 // DecodeBinary decodes AccountState from the given io.Reader.
 func (s *AccountState) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&s.Version)
 	br.ReadLE(&s.ScriptHash)
 	br.ReadLE(&s.IsFrozen)
@@ -96,7 +96,7 @@ func (s *AccountState) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary encode AccountState to the given io.Writer.
 func (s *AccountState) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(s.Version)
 	bw.WriteLE(s.ScriptHash)
 	bw.WriteLE(s.IsFrozen)

pkg/core/asset_state.go

@@ -47,7 +47,7 @@ type AssetState struct {
 
 // DecodeBinary implements the Payload interface.
 func (a *AssetState) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&a.ID)
 	br.ReadLE(&a.AssetType)
 
@@ -76,7 +76,7 @@ func (a *AssetState) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (a *AssetState) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(a.ID)
 	bw.WriteLE(a.AssetType)
 	bw.WriteString(a.Name)

pkg/core/block.go

@@ -78,7 +78,7 @@ func NewBlockFromTrimmedBytes(b []byte) (*Block, error) {
 		return block, err
 	}
 
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	var padding uint8
 	br.ReadLE(&padding)
 	if br.Err != nil {
@@ -109,7 +109,7 @@ func (b *Block) Trim() ([]byte, error) {
 	if err := b.encodeHashableFields(buf); err != nil {
 		return nil, err
 	}
-	bw := util.BinWriter{W: buf}
+	bw := util.NewBinWriterFromIO(buf)
 	bw.WriteLE(uint8(1))
 	if bw.Err != nil {
 		return nil, bw.Err
@@ -134,7 +134,7 @@ func (b *Block) DecodeBinary(r io.Reader) error {
 		return err
 	}
 
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lentx := br.ReadVarUint()
 	if br.Err != nil {
 		return br.Err
@@ -156,7 +156,7 @@ func (b *Block) EncodeBinary(w io.Writer) error {
 	if err != nil {
 		return err
 	}
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(b.Transactions)))
 	if bw.Err != nil {
 		return err

pkg/core/block_base.go

@@ -66,7 +66,7 @@ func (b *BlockBase) DecodeBinary(r io.Reader) error {
 	}
 
 	var padding uint8
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&padding)
 	if br.Err != nil {
 		return br.Err
@@ -84,7 +84,7 @@ func (b *BlockBase) EncodeBinary(w io.Writer) error {
 	if err := b.encodeHashableFields(w); err != nil {
 		return err
 	}
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(uint8(1))
 	if bw.Err != nil {
 		return bw.Err
@@ -111,7 +111,7 @@ func (b *BlockBase) createHash() error {
 // encodeHashableFields will only encode the fields used for hashing.
 // see Hash() for more information about the fields.
 func (b *BlockBase) encodeHashableFields(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(b.Version)
 	bw.WriteLE(b.PrevHash)
 	bw.WriteLE(b.MerkleRoot)
@@ -125,7 +125,7 @@ func (b *BlockBase) encodeHashableFields(w io.Writer) error {
 // decodeHashableFields will only decode the fields used for hashing.
 // see Hash() for more information about the fields.
 func (b *BlockBase) decodeHashableFields(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&b.Version)
 	br.ReadLE(&b.PrevHash)
 	br.ReadLE(&b.MerkleRoot)

pkg/core/header_hash_list.go

@@ -59,7 +59,7 @@ func (l *HeaderHashList) Slice(start, end int) []util.Uint256 {
 // WriteTo will write n underlying hashes to the given io.Writer
 // starting from start.
 func (l *HeaderHashList) Write(w io.Writer, start, n int) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(n))
 	hashes := l.Slice(start, start+n)
 	for _, hash := range hashes {

pkg/core/spent_coin_state.go

@@ -67,7 +67,7 @@ func NewSpentCoinState(hash util.Uint256, height uint32) *SpentCoinState {
 
 // DecodeBinary implements the Payload interface.
 func (s *SpentCoinState) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&s.txHash)
 	br.ReadLE(&s.txHeight)
 
@@ -87,7 +87,7 @@ func (s *SpentCoinState) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (s *SpentCoinState) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(s.txHash)
 	bw.WriteLE(s.txHeight)
 	bw.WriteVarUint(uint64(len(s.items)))

pkg/core/storage/helpers.go

@@ -84,7 +84,7 @@ func HeaderHashes(s Store) ([]util.Uint256, error) {
 // the given byte array.
 func read2000Uint256Hashes(b []byte) ([]util.Uint256, error) {
 	r := bytes.NewReader(b)
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lenHashes := br.ReadVarUint()
 	hashes := make([]util.Uint256, lenHashes)
 	br.ReadLE(hashes)

pkg/core/transaction/attribute.go

@@ -17,7 +17,7 @@ type Attribute struct {
 
 // DecodeBinary implements the Payload interface.
 func (attr *Attribute) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&attr.Usage)
 
 	// very special case
@@ -54,7 +54,7 @@ func (attr *Attribute) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (attr *Attribute) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(&attr.Usage)
 	switch attr.Usage {
 	case ECDH02, ECDH03:

pkg/core/transaction/claim.go

@@ -13,7 +13,7 @@ type ClaimTX struct {
 
 // DecodeBinary implements the Payload interface.
 func (tx *ClaimTX) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lenClaims := br.ReadVarUint()
 	if br.Err != nil {
 		return br.Err
@@ -30,7 +30,7 @@ func (tx *ClaimTX) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (tx *ClaimTX) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(tx.Claims)))
 	if bw.Err != nil {
 		return bw.Err

pkg/core/transaction/input.go

@@ -17,7 +17,7 @@ type Input struct {
 
 // DecodeBinary implements the Payload interface.
 func (in *Input) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&in.PrevHash)
 	br.ReadLE(&in.PrevIndex)
 	return br.Err
@@ -25,7 +25,7 @@ func (in *Input) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (in *Input) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(in.PrevHash)
 	bw.WriteLE(in.PrevIndex)
 	return bw.Err

pkg/core/transaction/invocation.go

@@ -34,7 +34,7 @@ func NewInvocationTX(script []byte) *Transaction {
 
 // DecodeBinary implements the Payload interface.
 func (tx *InvocationTX) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	tx.Script = br.ReadBytes()
 	if tx.Version >= 1 {
 		br.ReadLE(&tx.Gas)
@@ -46,7 +46,7 @@ func (tx *InvocationTX) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (tx *InvocationTX) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteBytes(tx.Script)
 	if tx.Version >= 1 {
 		bw.WriteLE(tx.Gas)

pkg/core/transaction/output.go

@@ -35,7 +35,7 @@ func NewOutput(assetID util.Uint256, amount util.Fixed8, scriptHash util.Uint160
 
 // DecodeBinary implements the Payload interface.
 func (out *Output) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&out.AssetID)
 	br.ReadLE(&out.Amount)
 	br.ReadLE(&out.ScriptHash)
@@ -44,7 +44,7 @@ func (out *Output) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (out *Output) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(out.AssetID)
 	bw.WriteLE(out.Amount)
 	bw.WriteLE(out.ScriptHash)

pkg/core/transaction/publish.go

@@ -24,7 +24,7 @@ type PublishTX struct {
 
 // DecodeBinary implements the Payload interface.
 func (tx *PublishTX) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	tx.Script = br.ReadBytes()
 
 	lenParams := br.ReadVarUint()
@@ -56,7 +56,7 @@ func (tx *PublishTX) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (tx *PublishTX) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteBytes(tx.Script)
 	bw.WriteVarUint(uint64(len(tx.ParamList)))
 	for _, param := range tx.ParamList {

pkg/core/transaction/register.go

@@ -31,7 +31,7 @@ type RegisterTX struct {
 
 // DecodeBinary implements the Payload interface.
 func (tx *RegisterTX) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&tx.AssetType)
 
 	tx.Name = br.ReadString()
@@ -53,7 +53,7 @@ func (tx *RegisterTX) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (tx *RegisterTX) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(tx.AssetType)
 	bw.WriteString(tx.Name)
 	bw.WriteLE(tx.Amount)

pkg/core/transaction/state.go

@@ -13,7 +13,7 @@ type StateTX struct {
 
 // DecodeBinary implements the Payload interface.
 func (tx *StateTX) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lenDesc := br.ReadVarUint()
 	if br.Err != nil {
 		return br.Err
@@ -30,7 +30,7 @@ func (tx *StateTX) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (tx *StateTX) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(tx.Descriptors)))
 	if bw.Err != nil {
 		return bw.Err

pkg/core/transaction/state_descriptor.go

@@ -25,7 +25,7 @@ type StateDescriptor struct {
 
 // DecodeBinary implements the Payload interface.
 func (s *StateDescriptor) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&s.Type)
 
 	s.Key = br.ReadBytes()
@@ -37,7 +37,7 @@ func (s *StateDescriptor) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (s *StateDescriptor) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(s.Type)
 	bw.WriteBytes(s.Key)
 	bw.WriteBytes(s.Value)

pkg/core/transaction/transaction.go

@@ -78,7 +78,7 @@ func (t *Transaction) AddInput(in *Input) {
 
 // DecodeBinary implements the payload interface.
 func (t *Transaction) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&t.Type)
 	br.ReadLE(&t.Version)
 	if br.Err != nil {
@@ -173,7 +173,7 @@ func (t *Transaction) EncodeBinary(w io.Writer) error {
 	if err := t.encodeHashableFields(w); err != nil {
 		return err
 	}
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(t.Scripts)))
 	if bw.Err != nil {
 		return bw.Err
@@ -189,7 +189,7 @@ func (t *Transaction) EncodeBinary(w io.Writer) error {
 // encodeHashableFields will only encode the fields that are not used for
 // signing the transaction, which are all fields except the scripts.
 func (t *Transaction) encodeHashableFields(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 
 	bw.WriteLE(t.Type)
 	bw.WriteLE(t.Version)

pkg/core/transaction/witness.go

@@ -17,7 +17,7 @@ type Witness struct {
 
 // DecodeBinary implements the payload interface.
 func (w *Witness) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 
 	w.InvocationScript = br.ReadBytes()
 	w.VerificationScript = br.ReadBytes()
@@ -26,7 +26,7 @@ func (w *Witness) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the payload interface.
 func (w *Witness) EncodeBinary(writer io.Writer) error {
-	bw := util.BinWriter{W: writer}
+	bw := util.NewBinWriterFromIO(writer)
 
 	bw.WriteBytes(w.InvocationScript)
 	bw.WriteBytes(w.VerificationScript)

pkg/core/unspent_coin_state.go

@@ -67,7 +67,7 @@ func (u UnspentCoins) commit(b storage.Batch) error {
 
 // EncodeBinary encodes UnspentCoinState to the given io.Writer.
 func (s *UnspentCoinState) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(s.states)))
 	for _, state := range s.states {
 		bw.WriteLE(byte(state))
@@ -77,7 +77,7 @@ func (s *UnspentCoinState) EncodeBinary(w io.Writer) error {
 
 // DecodeBinary decodes UnspentCoinState from the given io.Reader.
 func (s *UnspentCoinState) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lenStates := br.ReadVarUint()
 	s.states = make([]CoinState, lenStates)
 	for i := 0; i < int(lenStates); i++ {

pkg/network/message.go

@@ -148,7 +148,7 @@ func (m *Message) CommandType() CommandType {
 
 // Decode a Message from the given reader.
 func (m *Message) Decode(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&m.Magic)
 	br.ReadLE(&m.Command)
 	br.ReadLE(&m.Length)
@@ -232,7 +232,7 @@ func (m *Message) decodePayload(r io.Reader) error {
 
 // Encode a Message to any given io.Writer.
 func (m *Message) Encode(w io.Writer) error {
-	br := util.BinWriter{W: w}
+	br := util.NewBinWriterFromIO(w)
 	br.WriteLE(m.Magic)
 	br.WriteLE(m.Command)
 	br.WriteLE(m.Length)

pkg/network/payload/address.go

@@ -30,7 +30,7 @@ func NewAddressAndTime(e *net.TCPAddr, t time.Time) *AddressAndTime {
 
 // DecodeBinary implements the Payload interface.
 func (p *AddressAndTime) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&p.Timestamp)
 	br.ReadLE(&p.Services)
 	br.ReadBE(&p.IP)
@@ -40,7 +40,7 @@ func (p *AddressAndTime) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (p *AddressAndTime) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(p.Timestamp)
 	bw.WriteLE(p.Services)
 	bw.WriteBE(p.IP)
@@ -72,7 +72,7 @@ func NewAddressList(n int) *AddressList {
 
 // DecodeBinary implements the Payload interface.
 func (p *AddressList) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	listLen := br.ReadVarUint()
 	if br.Err != nil {
 		return br.Err
@@ -90,7 +90,7 @@ func (p *AddressList) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (p *AddressList) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(p.Addrs)))
 	if bw.Err != nil {
 		return bw.Err

pkg/network/payload/getblocks.go

@@ -24,7 +24,7 @@ func NewGetBlocks(start []util.Uint256, stop util.Uint256) *GetBlocks {
 
 // DecodeBinary implements the payload interface.
 func (p *GetBlocks) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lenStart := br.ReadVarUint()
 	p.HashStart = make([]util.Uint256, lenStart)
 
@@ -35,7 +35,7 @@ func (p *GetBlocks) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the payload interface.
 func (p *GetBlocks) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(p.HashStart)))
 	bw.WriteLE(p.HashStart)
 	bw.WriteLE(p.HashStop)

pkg/network/payload/headers.go

@@ -20,7 +20,7 @@ const (
 
 // DecodeBinary implements the Payload interface.
 func (p *Headers) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	lenHeaders := br.ReadVarUint()
 	if br.Err != nil {
 		return br.Err
@@ -46,7 +46,7 @@ func (p *Headers) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (p *Headers) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteVarUint(uint64(len(p.Hdrs)))
 	if bw.Err != nil {
 		return bw.Err

pkg/network/payload/inventory.go

@@ -57,7 +57,7 @@ func NewInventory(typ InventoryType, hashes []util.Uint256) *Inventory {
 
 // DecodeBinary implements the Payload interface.
 func (p *Inventory) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&p.Type)
 
 	listLen := br.ReadVarUint()
@@ -71,7 +71,7 @@ func (p *Inventory) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (p *Inventory) EncodeBinary(w io.Writer) error {
-	bw := util.BinWriter{W: w}
+	bw := util.NewBinWriterFromIO(w)
 	bw.WriteLE(p.Type)
 
 	listLen := len(p.Hashes)

pkg/network/payload/merkleblock.go

@@ -21,7 +21,7 @@ func (m *MerkleBlock) DecodeBinary(r io.Reader) error {
 	if err := m.BlockBase.DecodeBinary(r); err != nil {
 		return err
 	}
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 
 	m.TxCount = int(br.ReadVarUint())
 	n := br.ReadVarUint()

pkg/network/payload/version.go

@@ -56,7 +56,7 @@ func NewVersion(id uint32, p uint16, ua string, h uint32, r bool) *Version {
 
 // DecodeBinary implements the Payload interface.
 func (p *Version) DecodeBinary(r io.Reader) error {
-	br := util.BinReader{R: r}
+	br := util.NewBinReaderFromIO(r)
 	br.ReadLE(&p.Version)
 	br.ReadLE(&p.Services)
 	br.ReadLE(&p.Timestamp)
@@ -70,7 +70,7 @@ func (p *Version) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (p *Version) EncodeBinary(w io.Writer) error {
-	br := util.BinWriter{W: w}
+	br := util.NewBinWriterFromIO(w)
 	br.WriteLE(p.Version)
 	br.WriteLE(p.Services)
 	br.WriteLE(p.Timestamp)

pkg/smartcontract/contract_test.go

@@ -1,7 +1,6 @@
 package smartcontract
 
 import (
-	"bytes"
 	"testing"
 
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
@@ -22,8 +21,7 @@ func TestCreateMultiSigRedeemScript(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	buf := bytes.NewBuffer(out)
+	br := util.NewBinReaderFromBuf(out)
-	br := util.BinReader{R: buf}
 	var b uint8
 	br.ReadLE(&b)
 	assert.Equal(t, vm.PUSH3, vm.Instruction(b))

pkg/util/binaryBufWriter.go

@@ -0,0 +1,29 @@
+package util
+
+import (
+	"bytes"
+	"errors"
+)
+
+// BufBinWriter is an additional layer on top of BinWriter that
+// automatically creates buffer to write into that you can get after all
+// writes via Bytes().
+type BufBinWriter struct {
+	*BinWriter
+	buf *bytes.Buffer
+}
+
+// NewBufBinWriter makes a BufBinWriter with an empty byte buffer.
+func NewBufBinWriter() *BufBinWriter {
+	b := new(bytes.Buffer)
+	return &BufBinWriter{BinWriter: NewBinWriterFromIO(b), buf: b}
+}
+
+// Bytes returns resulting buffer and makes future writes return an error.
+func (bw *BufBinWriter) Bytes() []byte {
+	if bw.Err != nil {
+		return nil
+	}
+	bw.Err = errors.New("buffer already drained")
+	return bw.buf.Bytes()
+}

pkg/util/binaryReader.go

@@ -1,6 +1,7 @@
 package util
 
 import (
+	"bytes"
 	"encoding/binary"
 	"io"
 )
@@ -8,17 +9,28 @@ import (
 //BinReader is a convenient wrapper around a io.Reader and err object
 // Used to simplify error handling when reading into a struct with many fields
 type BinReader struct {
-	R   io.Reader
+	r   io.Reader
 	Err error
 }
 
+// NewBinReaderFromIO makes a BinReader from io.Reader.
+func NewBinReaderFromIO(ior io.Reader) *BinReader {
+	return &BinReader{r: ior}
+}
+
+// NewBinReaderFromBuf makes a BinReader from byte buffer.
+func NewBinReaderFromBuf(b []byte) *BinReader {
+	r := bytes.NewReader(b)
+	return NewBinReaderFromIO(r)
+}
+
 // ReadLE reads from the underlying io.Reader
 // into the interface v in little-endian format
 func (r *BinReader) ReadLE(v interface{}) {
 	if r.Err != nil {
 		return
 	}
-	r.Err = binary.Read(r.R, binary.LittleEndian, v)
+	r.Err = binary.Read(r.r, binary.LittleEndian, v)
 }
 
 // ReadBE reads from the underlying io.Reader
@@ -27,7 +39,7 @@ func (r *BinReader) ReadBE(v interface{}) {
 	if r.Err != nil {
 		return
 	}
-	r.Err = binary.Read(r.R, binary.BigEndian, v)
+	r.Err = binary.Read(r.r, binary.BigEndian, v)
 }
 
 // ReadVarUint reads a variable-length-encoded integer from the
@@ -38,21 +50,21 @@ func (r *BinReader) ReadVarUint() uint64 {
 	}
 
 	var b uint8
-	r.Err = binary.Read(r.R, binary.LittleEndian, &b)
+	r.Err = binary.Read(r.r, binary.LittleEndian, &b)
 
 	if b == 0xfd {
 		var v uint16
-		r.Err = binary.Read(r.R, binary.LittleEndian, &v)
+		r.Err = binary.Read(r.r, binary.LittleEndian, &v)
 		return uint64(v)
 	}
 	if b == 0xfe {
 		var v uint32
-		r.Err = binary.Read(r.R, binary.LittleEndian, &v)
+		r.Err = binary.Read(r.r, binary.LittleEndian, &v)
 		return uint64(v)
 	}
 	if b == 0xff {
 		var v uint64
-		r.Err = binary.Read(r.R, binary.LittleEndian, &v)
+		r.Err = binary.Read(r.r, binary.LittleEndian, &v)
 		return v
 	}
 

pkg/util/binaryWriter.go

@@ -10,16 +10,21 @@ import (
 // Used to simplify error handling when writing into a io.Writer
 // from a struct with many fields
 type BinWriter struct {
-	W   io.Writer
+	w   io.Writer
 	Err error
 }
 
+// NewBinWriterFromIO makes a BinWriter from io.Writer.
+func NewBinWriterFromIO(iow io.Writer) *BinWriter {
+	return &BinWriter{w: iow}
+}
+
 // WriteLE writes into the underlying io.Writer from an object v in little-endian format
 func (w *BinWriter) WriteLE(v interface{}) {
 	if w.Err != nil {
 		return
 	}
-	w.Err = binary.Write(w.W, binary.LittleEndian, v)
+	w.Err = binary.Write(w.w, binary.LittleEndian, v)
 }
 
 // WriteBE writes into the underlying io.Writer from an object v in big-endian format
@@ -27,7 +32,7 @@ func (w *BinWriter) WriteBE(v interface{}) {
 	if w.Err != nil {
 		return
 	}
-	w.Err = binary.Write(w.W, binary.BigEndian, v)
+	w.Err = binary.Write(w.w, binary.BigEndian, v)
 }
 
 // WriteVarUint writes a uint64 into the underlying writer using variable-length encoding
@@ -46,23 +51,23 @@ func (w *BinWriter) WriteVarUint(val uint64) {
 	}
 
 	if val < 0xfd {
-		w.Err = binary.Write(w.W, binary.LittleEndian, uint8(val))
+		w.Err = binary.Write(w.w, binary.LittleEndian, uint8(val))
 		return
 	}
 	if val < 0xFFFF {
-		w.Err = binary.Write(w.W, binary.LittleEndian, byte(0xfd))
+		w.Err = binary.Write(w.w, binary.LittleEndian, byte(0xfd))
-		w.Err = binary.Write(w.W, binary.LittleEndian, uint16(val))
+		w.Err = binary.Write(w.w, binary.LittleEndian, uint16(val))
 		return
 	}
 	if val < 0xFFFFFFFF {
-		w.Err = binary.Write(w.W, binary.LittleEndian, byte(0xfe))
+		w.Err = binary.Write(w.w, binary.LittleEndian, byte(0xfe))
-		w.Err = binary.Write(w.W, binary.LittleEndian, uint32(val))
+		w.Err = binary.Write(w.w, binary.LittleEndian, uint32(val))
 		return
 
 	}
 
-	w.Err = binary.Write(w.W, binary.LittleEndian, byte(0xff))
+	w.Err = binary.Write(w.w, binary.LittleEndian, byte(0xff))
-	w.Err = binary.Write(w.W, binary.LittleEndian, val)
+	w.Err = binary.Write(w.w, binary.LittleEndian, val)
 
 }
 

pkg/util/binaryrw_test.go

@@ -1,7 +1,6 @@
 package util
 
 import (
-	"bytes"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -10,25 +9,25 @@ import (
 func TestWriteVarUint1(t *testing.T) {
 	var (
 		val = uint64(1)
-		buf = new(bytes.Buffer)
 	)
-	bw := BinWriter{W: buf}
+	bw := NewBufBinWriter()
 	bw.WriteVarUint(val)
 	assert.Nil(t, bw.Err)
-	assert.Equal(t, 1, buf.Len())
+	buf := bw.Bytes()
+	assert.Equal(t, 1, len(buf))
 }
 
 func TestWriteVarUint1000(t *testing.T) {
 	var (
 		val = uint64(1000)
-		buf = new(bytes.Buffer)
 	)
-	bw := BinWriter{W: buf}
+	bw := NewBufBinWriter()
 	bw.WriteVarUint(val)
 	assert.Nil(t, bw.Err)
-	assert.Equal(t, 3, buf.Len())
+	buf := bw.Bytes()
-	assert.Equal(t, byte(0xfd), buf.Bytes()[0])
+	assert.Equal(t, 3, len(buf))
-	br := BinReader{R: buf}
+	assert.Equal(t, byte(0xfd), buf[0])
+	br := NewBinReaderFromBuf(buf)
 	res := br.ReadVarUint()
 	assert.Nil(t, br.Err)
 	assert.Equal(t, val, res)
@@ -37,14 +36,14 @@ func TestWriteVarUint1000(t *testing.T) {
 func TestWriteVarUint100000(t *testing.T) {
 	var (
 		val = uint64(100000)
-		buf = new(bytes.Buffer)
 	)
-	bw := BinWriter{W: buf}
+	bw := NewBufBinWriter()
 	bw.WriteVarUint(val)
 	assert.Nil(t, bw.Err)
-	assert.Equal(t, 5, buf.Len())
+	buf := bw.Bytes()
-	assert.Equal(t, byte(0xfe), buf.Bytes()[0])
+	assert.Equal(t, 5, len(buf))
-	br := BinReader{R: buf}
+	assert.Equal(t, byte(0xfe), buf[0])
+	br := NewBinReaderFromBuf(buf)
 	res := br.ReadVarUint()
 	assert.Nil(t, br.Err)
 	assert.Equal(t, val, res)
@@ -53,14 +52,14 @@ func TestWriteVarUint100000(t *testing.T) {
 func TestWriteVarUint100000000000(t *testing.T) {
 	var (
 		val = uint64(1000000000000)
-		buf = new(bytes.Buffer)
 	)
-	bw := BinWriter{W: buf}
+	bw := NewBufBinWriter()
 	bw.WriteVarUint(val)
 	assert.Nil(t, bw.Err)
-	assert.Equal(t, 9, buf.Len())
+	buf := bw.Bytes()
-	assert.Equal(t, byte(0xff), buf.Bytes()[0])
+	assert.Equal(t, 9, len(buf))
-	br := BinReader{R: buf}
+	assert.Equal(t, byte(0xff), buf[0])
+	br := NewBinReaderFromBuf(buf)
 	res := br.ReadVarUint()
 	assert.Nil(t, br.Err)
 	assert.Equal(t, val, res)