Golang MsgTx.Deserialize Examples

Example #1

File: tx.go Project: evansuva/pointcoind

// fetchTxDataByLoc returns several pieces of data regarding the given tx
// located by the block/offset/size location
func (db *LevelDb) fetchTxDataByLoc(blkHeight int64, txOff int, txLen int, txspent []byte) (rtx *btcwire.MsgTx, rblksha *btcwire.ShaHash, rheight int64, rtxspent []byte, err error) {
	var blksha *btcwire.ShaHash
	var blkbuf []byte

	blksha, blkbuf, err = db.getBlkByHeight(blkHeight)
	if err != nil {
		if err == leveldb.ErrNotFound {
			err = database.ErrTxShaMissing
		}
		return
	}

	//log.Trace("transaction %v is at block %v %v txoff %v, txlen %v\n",
	//	txsha, blksha, blkHeight, txOff, txLen)

	if len(blkbuf) < txOff+txLen {
		err = database.ErrTxShaMissing
		return
	}
	rbuf := bytes.NewReader(blkbuf[txOff : txOff+txLen])

	var tx btcwire.MsgTx
	err = tx.Deserialize(rbuf)
	if err != nil {
		log.Warnf("unable to decode tx block %v %v txoff %v txlen %v",
			blkHeight, blksha, txOff, txLen)
		return
	}

	return &tx, blksha, blkHeight, txspent, nil
}

Example #2

File: common_test.go Project: evansuva/pointcoind

// loadTxStore returns a transaction store loaded from a file.
func loadTxStore(filename string) (blockchain.TxStore, error) {
	// The txstore file format is:
	// <num tx data entries> <tx length> <serialized tx> <blk height>
	// <num spent bits> <spent bits>
	//
	// All num and length fields are little-endian uint32s.  The spent bits
	// field is padded to a byte boundary.

	filename = filepath.Join("testdata/", filename)
	fi, err := os.Open(filename)
	if err != nil {
		return nil, err
	}

	// Choose read based on whether the file is compressed or not.
	var r io.Reader
	if strings.HasSuffix(filename, ".bz2") {
		r = bzip2.NewReader(fi)
	} else {
		r = fi
	}
	defer fi.Close()

	// Num of transaction store objects.
	var numItems uint32
	if err := binary.Read(r, binary.LittleEndian, &numItems); err != nil {
		return nil, err
	}

	txStore := make(blockchain.TxStore)
	var uintBuf uint32
	for height := uint32(0); height < numItems; height++ {
		txD := blockchain.TxData{}

		// Serialized transaction length.
		err = binary.Read(r, binary.LittleEndian, &uintBuf)
		if err != nil {
			return nil, err
		}
		serializedTxLen := uintBuf
		if serializedTxLen > btcwire.MaxBlockPayload {
			return nil, fmt.Errorf("Read serialized transaction "+
				"length of %d is larger max allowed %d",
				serializedTxLen, btcwire.MaxBlockPayload)
		}

		// Transaction.
		var msgTx btcwire.MsgTx
		err = msgTx.Deserialize(r)
		if err != nil {
			return nil, err
		}
		txD.Tx = btcutil.NewTx(&msgTx)

		// Transaction hash.
		txHash, err := msgTx.TxSha()
		if err != nil {
			return nil, err
		}
		txD.Hash = &txHash

		// Block height the transaction came from.
		err = binary.Read(r, binary.LittleEndian, &uintBuf)
		if err != nil {
			return nil, err
		}
		txD.BlockHeight = int64(uintBuf)

		// Num spent bits.
		err = binary.Read(r, binary.LittleEndian, &uintBuf)
		if err != nil {
			return nil, err
		}
		numSpentBits := uintBuf
		numSpentBytes := numSpentBits / 8
		if numSpentBits%8 != 0 {
			numSpentBytes++
		}

		// Packed spent bytes.
		spentBytes := make([]byte, numSpentBytes)
		_, err = io.ReadFull(r, spentBytes)
		if err != nil {
			return nil, err
		}

		// Populate spent data based on spent bits.
		txD.Spent = make([]bool, numSpentBits)
		for byteNum, spentByte := range spentBytes {
			for bit := 0; bit < 8; bit++ {
				if uint32((byteNum*8)+bit) < numSpentBits {
					if spentByte&(1<<uint(bit)) != 0 {
						txD.Spent[(byteNum*8)+bit] = true
					}
				}
			}
		}

		txStore[*txD.Hash] = &txD
	}

	return txStore, nil
}