blockbook/bchain/coins/utils/parserutils.go

106 lines
2.8 KiB
Go

package utils
import (
"fmt"
"io"
"github.com/btcsuite/btcd/wire"
)
// minTxPayload is the minimum payload size for a transaction. Note
// that any realistically usable transaction must have at least one
// input or output, but that is a rule enforced at a higher layer, so
// it is intentionally not included here.
// Version 4 bytes + Varint number of transaction inputs 1 byte + Varint
// number of transaction outputs 1 byte + LockTime 4 bytes + min input
// payload + min output payload.
const minTxPayload = 10
// maxTxPerBlock is the maximum number of transactions that could
// possibly fit into a block.
const maxTxPerBlock = (wire.MaxBlockPayload / minTxPayload) + 1
// DecodeTransactions decodes transactions from input stream using wire
func DecodeTransactions(r io.Reader, pver uint32, enc wire.MessageEncoding, blk *wire.MsgBlock) error {
txCount, err := wire.ReadVarInt(r, pver)
if err != nil {
return err
}
// Prevent more transactions than could possibly fit into a block.
// It would be possible to cause memory exhaustion and panics without
// a sane upper bound on this count.
if txCount > maxTxPerBlock {
str := fmt.Sprintf("too many transactions to fit into a block "+
"[count %d, max %d]", txCount, maxTxPerBlock)
return &wire.MessageError{Func: "utils.decodeTransactions", Description: str}
}
blk.Transactions = make([]*wire.MsgTx, 0, txCount)
for i := uint64(0); i < txCount; i++ {
tx := wire.MsgTx{}
err := tx.BtcDecode(r, pver, enc)
if err != nil {
return err
}
blk.Transactions = append(blk.Transactions, &tx)
}
return nil
}
// VersionAuxpow marks that block contains Auxpow
const VersionAuxpow = (1 << 8)
// SkipAuxpow skips Auxpow data in block
func SkipAuxpow(r io.ReadSeeker) error {
// skip Auxpow part of the block
// https://github.com/dogecoin/dogecoin/blob/master/src/auxpow.h#L130
// CMerkleTx CTransaction
tx := wire.MsgTx{}
err := tx.BtcDecode(r, 0, wire.WitnessEncoding)
if err != nil {
return err
}
// CMerkleTx uint256 hashBlock
_, err = r.Seek(32, io.SeekCurrent)
if err != nil {
return err
}
// CMerkleTx std::vector<uint256> vMerkleBranch
size, err := wire.ReadVarInt(r, 0)
if err != nil {
return err
}
_, err = r.Seek(int64(size)*32, io.SeekCurrent)
if err != nil {
return err
}
// CMerkleTx int nIndex
_, err = r.Seek(4, io.SeekCurrent)
if err != nil {
return err
}
// CAuxPow std::vector<uint256> vChainMerkleBranch;
size, err = wire.ReadVarInt(r, 0)
if err != nil {
return err
}
_, err = r.Seek(int64(size)*32, io.SeekCurrent)
if err != nil {
return err
}
// CAuxPow int nChainIndex;
_, err = r.Seek(4, io.SeekCurrent)
if err != nil {
return err
}
// CAuxPow CPureBlockHeader parentBlock;
ph := wire.BlockHeader{}
err = ph.Deserialize(r)
if err != nil {
return err
}
return nil
}