lbcd/wire/msgcfilterheader.go

79 lines
2.8 KiB
Go

// Copyright (c) 2017 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"
"github.com/btcsuite/fastsha256"
"io"
)
const (
// MaxCFilterHeaderDataSize is the maximum byte size of a committed
// filter header.
MaxCFilterHeaderDataSize = fastsha256.Size
)
type MsgCFilterHeader struct {
Data []byte
}
// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
// This is part of the Message interface implementation.
func (msg *MsgCFilterHeader) BtcDecode(r io.Reader, pver uint32) error {
var err error
msg.Data, err = ReadVarBytes(r, pver, MaxCFilterHeaderDataSize,
"cf header data")
return err
}
// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
// This is part of the Message interface implementation.
func (msg *MsgCFilterHeader) BtcEncode(w io.Writer, pver uint32) error {
size := len(msg.Data)
if size > MaxCFilterHeaderDataSize {
str := fmt.Sprintf("cf header size too large for message " +
"[size %v, max %v]", size, MaxCFilterHeaderDataSize)
return messageError("MsgCFilterHeader.BtcEncode", str)
}
return WriteVarBytes(w, pver, msg.Data)
}
// Deserialize decodes a filter header from r into the receiver using a format
// that is suitable for long-term storage such as a database. This function
// differs from BtcDecode in that BtcDecode decodes from the bitcoin wire
// protocol as it was sent across the network. The wire encoding can
// technically differ depending on the protocol version and doesn't even really
// need to match the format of a stored filter header at all. As of the time
// this comment was written, the encoded filter header is the same in both
// instances, but there is a distinct difference and separating the two allows
// the API to be flexible enough to deal with changes.
func (msg *MsgCFilterHeader) Deserialize(r io.Reader) error {
// At the current time, there is no difference between the wire encoding
// and the stable long-term storage format. As a result, make use of
// BtcDecode.
return msg.BtcDecode(r, 0)
}
// Command returns the protocol command string for the message. This is part
// of the Message interface implementation.
func (msg *MsgCFilterHeader) Command() string {
return CmdCFilterHeader
}
// MaxPayloadLength returns the maximum length the payload can be for the
// receiver. This is part of the Message interface implementation.
func (msg *MsgCFilterHeader) MaxPayloadLength(pver uint32) uint32 {
return uint32(VarIntSerializeSize(MaxCFilterHeaderDataSize)) +
MaxCFilterHeaderDataSize
}
// NewMsgFilterAdd returns a new bitcoin cfilterheader message that conforms to
// the Message interface. See MsgCFilterHeader for details.
func NewMsgCFilterHeader(data []byte) *MsgCFilterHeader {
return &MsgCFilterHeader{
Data: data,
}
}