class CBlock(object):
def __init__(self):
    self.nVersion = 1
    self.hashPrevBlock = 0
    self.hashMerkleRoot = 0
    self.nTime = 0
    self.nBits = 0
    self.nNonce = 0
    self.vtx = []
    self.sha256 = None
    self.hash = None
def deserialize(self, f):
    self.nVersion = struct.unpack("<i", f.read(4))[0]
    self.hashPrevBlock = deser_uint256(f)
    self.hashMerkleRoot = deser_uint256(f)
    self.nTime = struct.unpack("<I", f.read(4))[0]
    self.nBits = struct.unpack("<I", f.read(4))[0]
    self.nNonce = struct.unpack("<I", f.read(4))[0]
    self.vtx = deser_vector(f, CTransaction)
def serialize(self):
    r = ""
    r += struct.pack("<i", self.nVersion)
    r += ser_uint256(self.hashPrevBlock)
    r += ser_uint256(self.hashMerkleRoot)
    r += struct.pack("<I", self.nTime)
    r += struct.pack("<I", self.nBits)
    r += struct.pack("<I", self.nNonce)
    r += ser_vector(self.vtx)
    return r
def calc_sha256(self):
    if self.sha256 is None:
        r = ""
        r += struct.pack("<i", self.nVersion)
        r += ser_uint256(self.hashPrevBlock)
        r += ser_uint256(self.hashMerkleRoot)
        r += struct.pack("<I", self.nTime)
        r += struct.pack("<I", self.nBits)
        r += struct.pack("<I", self.nNonce)
        self.sha256 = uint256_from_str(hash256(r))
        self.hash = hash256(r)[::-1].encode('hex_codec')
def is_valid(self):
    self.calc_sha256()
    target = uint256_from_compact(self.nBits)
    if self.sha256 > target:
        return False
    hashes = []
    for tx in self.vtx:
        if not tx.is_valid():
            return False
        tx.calc_sha256()
        hashes.append(ser_uint256(tx.sha256))
    while len(hashes) > 1:
        newhashes = []
        for i in xrange(0, len(hashes), 2):
            i2 = min(i+1, len(hashes)-1)
            newhashes.append(hash256(hashes[i] + hashes[i2]))
        hashes = newhashes
    if uint256_from_str(hashes[0]) != self.hashMerkleRoot:
        return False
    return True
def __repr__(self):
    return "CBlock(nVersion=%i hashPrevBlock=%064x hashMerkleRoot=%064x nTime=%s nBits=%08x nNonce=%08x vtx=%s)" % (self.nVersion, self.hashPrevBlock, self.hashMerkleRoot, time.ctime(self.nTime), self.nBits, self.nNonce, repr(self.vtx))