status-go/vendor/github.com/btcsuite/btcd/wire/msgmerkleblock.go

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// Copyright (c) 2014-2016 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package wire
import (
"fmt"
"io"
"github.com/btcsuite/btcd/chaincfg/chainhash"
)
// maxFlagsPerMerkleBlock is the maximum number of flag bytes that could
// possibly fit into a merkle block. Since each transaction is represented by
// a single bit, this is the max number of transactions per block divided by
// 8 bits per byte. Then an extra one to cover partials.
const maxFlagsPerMerkleBlock = maxTxPerBlock / 8
// MsgMerkleBlock implements the Message interface and represents a bitcoin
// merkleblock message which is used to reset a Bloom filter.
//
// This message was not added until protocol version BIP0037Version.
type MsgMerkleBlock struct {
Header BlockHeader
Transactions uint32
Hashes []*chainhash.Hash
Flags []byte
}
// AddTxHash adds a new transaction hash to the message.
func (msg *MsgMerkleBlock) AddTxHash(hash *chainhash.Hash) error {
if len(msg.Hashes)+1 > maxTxPerBlock {
str := fmt.Sprintf("too many tx hashes for message [max %v]",
maxTxPerBlock)
return messageError("MsgMerkleBlock.AddTxHash", str)
}
msg.Hashes = append(msg.Hashes, hash)
return nil
}
// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
// This is part of the Message interface implementation.
func (msg *MsgMerkleBlock) BtcDecode(r io.Reader, pver uint32) error {
if pver < BIP0037Version {
str := fmt.Sprintf("merkleblock message invalid for protocol "+
"version %d", pver)
return messageError("MsgMerkleBlock.BtcDecode", str)
}
err := readBlockHeader(r, pver, &msg.Header)
if err != nil {
return err
}
err = readElement(r, &msg.Transactions)
if err != nil {
return err
}
// Read num block locator hashes and limit to max.
count, err := ReadVarInt(r, pver)
if err != nil {
return err
}
if count > maxTxPerBlock {
str := fmt.Sprintf("too many transaction hashes for message "+
"[count %v, max %v]", count, maxTxPerBlock)
return messageError("MsgMerkleBlock.BtcDecode", str)
}
// Create a contiguous slice of hashes to deserialize into in order to
// reduce the number of allocations.
hashes := make([]chainhash.Hash, count)
msg.Hashes = make([]*chainhash.Hash, 0, count)
for i := uint64(0); i < count; i++ {
hash := &hashes[i]
err := readElement(r, hash)
if err != nil {
return err
}
msg.AddTxHash(hash)
}
msg.Flags, err = ReadVarBytes(r, pver, maxFlagsPerMerkleBlock,
"merkle block flags size")
return err
}
// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
// This is part of the Message interface implementation.
func (msg *MsgMerkleBlock) BtcEncode(w io.Writer, pver uint32) error {
if pver < BIP0037Version {
str := fmt.Sprintf("merkleblock message invalid for protocol "+
"version %d", pver)
return messageError("MsgMerkleBlock.BtcEncode", str)
}
// Read num transaction hashes and limit to max.
numHashes := len(msg.Hashes)
if numHashes > maxTxPerBlock {
str := fmt.Sprintf("too many transaction hashes for message "+
"[count %v, max %v]", numHashes, maxTxPerBlock)
return messageError("MsgMerkleBlock.BtcDecode", str)
}
numFlagBytes := len(msg.Flags)
if numFlagBytes > maxFlagsPerMerkleBlock {
str := fmt.Sprintf("too many flag bytes for message [count %v, "+
"max %v]", numFlagBytes, maxFlagsPerMerkleBlock)
return messageError("MsgMerkleBlock.BtcDecode", str)
}
err := writeBlockHeader(w, pver, &msg.Header)
if err != nil {
return err
}
err = writeElement(w, msg.Transactions)
if err != nil {
return err
}
err = WriteVarInt(w, pver, uint64(numHashes))
if err != nil {
return err
}
for _, hash := range msg.Hashes {
err = writeElement(w, hash)
if err != nil {
return err
}
}
return WriteVarBytes(w, pver, msg.Flags)
}
// Command returns the protocol command string for the message. This is part
// of the Message interface implementation.
func (msg *MsgMerkleBlock) Command() string {
return CmdMerkleBlock
}
// MaxPayloadLength returns the maximum length the payload can be for the
// receiver. This is part of the Message interface implementation.
func (msg *MsgMerkleBlock) MaxPayloadLength(pver uint32) uint32 {
return MaxBlockPayload
}
// NewMsgMerkleBlock returns a new bitcoin merkleblock message that conforms to
// the Message interface. See MsgMerkleBlock for details.
func NewMsgMerkleBlock(bh *BlockHeader) *MsgMerkleBlock {
return &MsgMerkleBlock{
Header: *bh,
Transactions: 0,
Hashes: make([]*chainhash.Hash, 0),
Flags: make([]byte, 0),
}
}