def test_unpackers():
b = bytes(range(256))
assert util.unpack_le_int32_from(b, 0) == (50462976, )
assert util.unpack_le_int32_from(b, 42) == (757869354, )
assert util.unpack_le_int64_from(b, 0) == (506097522914230528, )
assert util.unpack_le_int64_from(b, 42) == (3544384782113450794, )
assert util.unpack_le_uint16_from(b, 0) == (256, )
assert util.unpack_le_uint16_from(b, 42) == (11050, )
assert util.unpack_le_uint32_from(b, 0) == (50462976, )
assert util.unpack_le_uint32_from(b, 42) == (757869354, )
assert util.unpack_le_uint64_from(b, 0) == (506097522914230528, )
assert util.unpack_le_uint64_from(b, 42) == (3544384782113450794, )
def get_ops(cls, script):
ops = []
# The unpacks or script[n] below throw on truncated scripts
try:
n = 0
while n < len(script):
op = script[n]
n += 1
if op <= OpCodes.OP_PUSHDATA4:
# Raw bytes follow
if op < OpCodes.OP_PUSHDATA1:
dlen = op
elif op == OpCodes.OP_PUSHDATA1:
dlen = script[n]
n += 1
elif op == OpCodes.OP_PUSHDATA2:
dlen, = unpack_le_uint16_from(script[n:n + 2])
n += 2
else:
dlen, = unpack_le_uint32_from(script[n:n + 4])
n += 4
if n + dlen > len(script):
raise IndexError
op = (op, script[n:n + dlen])
n += dlen
ops.append(op)
except Exception:
# Truncated script; e.g. tx_hash
# ebc9fa1196a59e192352d76c0f6e73167046b9d37b8302b6bb6968dfd279b767
raise ScriptError('truncated script') from None
return ops
def header_hash(cls, header):
'''Given a header return the hash.'''
if cls.HEADER_HASH is None:
import scrypt
cls.HEADER_HASH = lambda x: scrypt.hash(x, x, 1024, 1, 1, 32)
version, = util.unpack_le_uint32_from(header)
if version > 6:
return super().header_hash(header)
else:
return cls.HEADER_HASH(header)
def get_ops(cls, script):
'''
Returns a tuple list of (op_code, index of next op in script, pushed bytes if any)
If at any point the script fails do decode, a tuple of (-1, len(script), remaining script) is appended
'''
ops = []
# The unpacks or script[n]
n = 0
try:
while n < len(script):
op = script[n]
op_v = (script[n], n + 1)
n += 1
if op <= OpCodes.OP_PUSHDATA4:
# Raw bytes follow
if op < OpCodes.OP_PUSHDATA1:
dlen = op
n1 = 0
elif op == OpCodes.OP_PUSHDATA1:
dlen = script[n]
n1 = 1
elif op == OpCodes.OP_PUSHDATA2:
dlen, = unpack_le_uint16_from(script[n:n + 2])
n1 = 2
else:
dlen, = unpack_le_uint32_from(script[n:n + 4])
n1 = 4
if n + n1 + dlen > len(script):
raise IndexError
n += n1
op_v = (op, n + dlen, script[n:n + dlen])
n += dlen
ops.append(op_v)
except (IndexError, struct.error):
# n - 1 because we read a byte first
ops.append((-1, len(script), script[n - 1:]))
return ops
def _read_le_uint32(self):
result, = unpack_le_uint32_from(self.binary, self.cursor)
self.cursor += 4
return result
def read_le_uint32(buf, cursor):
result, = unpack_le_uint32_from(buf, cursor)
return result, cursor + 4
