def parse(cls: Type[_Tx],
data: BinaryData,
check_validity: bool = True) -> _Tx:
"Return a Tx by parsing binary data."
stream = bytesio_from_binarydata(data)
# version is a signed int (int32_t, not uint32_t)
version = int.from_bytes(stream.read(4),
byteorder="little",
signed=True)
segwit = stream.read(2) == _SEGWIT_MARKER
if not segwit:
# Change stream position: seek to byte offset relative to position
stream.seek(-2, SEEK_CUR) # current position
n = var_int.parse(stream)
vin = [TxIn.parse(stream) for _ in range(n)]
n = var_int.parse(stream)
vout = [TxOut.parse(stream) for _ in range(n)]
if segwit:
for tx_in in vin:
tx_in.script_witness = Witness.parse(stream, check_validity)
lock_time = int.from_bytes(stream.read(4),
byteorder="little",
signed=False)
return cls(version, lock_time, vin, vout, check_validity)
def deserialize_map(data: BinaryData) -> Tuple[Dict[bytes, bytes], BytesIO]:
stream = bytesio_from_binarydata(data)
if (
len(stream.getbuffer()) == stream.tell()
): # we are at the end of the stream buffer
raise BTClibValueError("malformed psbt: at least a map is missing")
partial_map: Dict[bytes, bytes] = {}
while True:
if stream.read(1)[0] == 0:
return partial_map, stream
stream.seek(-1, 1) # reset stream position
key = stream.read(var_int.parse(stream))
value = stream.read(var_int.parse(stream))
if key in partial_map:
raise BTClibValueError(f"duplicated key in psbt map: 0x{key.hex()}")
partial_map[key] = value
def parse(cls: Type["Witness"],
data: BinaryData,
check_validity: bool = True) -> "Witness":
"Return a Witness by parsing binary data."
data = bytesio_from_binarydata(data)
n = var_int.parse(data)
stack = [var_bytes.parse(data) for _ in range(n)]
return cls(stack, check_validity)
def deserialize_map(psbt_bin: bytes) -> Tuple[Dict[bytes, bytes], bytes]:
if len(psbt_bin) == 0:
raise BTClibValueError("malformed psbt: at least a map is missing")
partial_map: Dict[bytes, bytes] = {}
while True:
if psbt_bin[0] == 0:
psbt_bin = psbt_bin[1:]
return partial_map, psbt_bin
key_len = var_int.parse(psbt_bin)
psbt_bin = psbt_bin[len(var_int.serialize(key_len)):]
key = psbt_bin[:key_len]
psbt_bin = psbt_bin[key_len:]
value_len = var_int.parse(psbt_bin)
psbt_bin = psbt_bin[len(var_int.serialize(value_len)):]
value = psbt_bin[:value_len]
psbt_bin = psbt_bin[value_len:]
if key in partial_map:
raise BTClibValueError(
f"duplicated key in psbt map: 0x{key.hex()}")
partial_map[key] = value
def parse(cls: Type[_Block],
data: BinaryData,
check_validity: bool = True) -> _Block:
"Return a Block by parsing binary data."
stream = bytesio_from_binarydata(data)
header = BlockHeader.parse(stream)
n = var_int.parse(stream)
# TODO: is a block required to have a coinbase tx?
transactions = [Tx.parse(stream) for _ in range(n)]
return cls(header, transactions, check_validity)
def parse(stream: BinaryData, forbid_zero_size: bool = False) -> bytes:
"""Return the variable-length octets read from a stream."""
stream = bytesio_from_binarydata(stream)
i = var_int.parse(stream)
if forbid_zero_size and i == 0:
raise BTClibRuntimeError("zero size")
result = stream.read(i)
if len(result) != i:
raise BTClibRuntimeError("not enough binary data")
return result
def parse(cls: Type["Tx"],
data: BinaryData,
check_validity: bool = True) -> "Tx":
"Return a Tx by parsing binary data."
stream = bytesio_from_binarydata(data)
# version is a signed int (int32_t) in bitcoin_core
# However there are at least two transactions:
# 35e79ee733fad376e76d16d1f10088273c2f4c2eaba1374a837378a88e530005
# c659729a7fea5071361c2c1a68551ca2bf77679b27086cc415adeeb03852e369
# where the version number is negative if it is considered as a signed
# integer. As such in btclib the version is an UNSIGNED integer.
# This has been discussed in: https://github.com/bitcoin/bitcoin/pull/16525
version = int.from_bytes(stream.read(4),
byteorder="little",
signed=False)
segwit = stream.read(2) == _SEGWIT_MARKER
if not segwit:
# Change stream position: seek to byte offset relative to position
stream.seek(-2, SEEK_CUR) # current position
n = var_int.parse(stream)
vin = [TxIn.parse(stream) for _ in range(n)]
n = var_int.parse(stream)
vout = [TxOut.parse(stream) for _ in range(n)]
if segwit:
for tx_in in vin:
tx_in.script_witness = Witness.parse(stream, check_validity)
lock_time = int.from_bytes(stream.read(4),
byteorder="little",
signed=False)
return cls(version, lock_time, vin, vout, check_validity)
def test_var_int_conversion() -> None:
int_ = -1
with pytest.raises(BTClibValueError, match="negative integer: "):
var_int.serialize(int_)
int_ = 0x00
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 1
assert var_int.parse(bytes_) == int_
int_ += 1
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 1
assert var_int.parse(bytes_) == int_
int_ = 0xFC
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 1
assert var_int.parse(bytes_) == int_
int_ += 1
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 3
assert var_int.parse(bytes_) == int_
int_ = 0xFFFF
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 3
assert var_int.parse(bytes_) == int_
int_ += 1
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 5
assert var_int.parse(bytes_) == int_
int_ = 0xFFFFFFFF
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 5
assert var_int.parse(bytes_) == int_
int_ += 1
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 9
assert var_int.parse(bytes_) == int_
int_ = 0xFFFFFFFFFFFFFFFF
bytes_ = var_int.serialize(int_)
assert len(bytes_) == 9
assert var_int.parse(bytes_) == int_
int_ += 1
with pytest.raises(BTClibValueError,
match="integer too big for var_int encoding: "):
var_int.serialize(int_)
assert var_int.parse("6a") == 106
assert var_int.parse("fd2602") == 550
assert var_int.parse("fe703a0f00") == 998000
