Class CScript

bitcoin/core/script.py:503–811

Serialized script A bytes subclass, so you can use this directly whenever bytes are accepted. Note that this means that indexing does *not* work - you'll get an index by byte rather than opcode. This format was chosen for efficiency so that the general case would not require creatin

        super(CScriptTruncatedPushDataError, self).__init__(msg)

class CScript(bytes):
    """Serialized script

    A bytes subclass, so you can use this directly whenever bytes are accepted.
    Note that this means that indexing does *not* work - you'll get an index by
    byte rather than opcode. This format was chosen for efficiency so that the
    general case would not require creating a lot of little CScriptOP objects.

    iter(script) however does iterate by opcode.
    """
    @classmethod
    def __coerce_instance(cls, other):
        # Coerce other into bytes
        if isinstance(other, CScriptOp):
            other = bytes([other])
        elif isinstance(other, int):
            if 0 <= other <= 16:
                other = bytes([CScriptOp.encode_op_n(other)])
            elif other == -1:
                other = bytes([OP_1NEGATE])
            else:
                other = CScriptOp.encode_op_pushdata(bitcoin.core._bignum.bn2vch(other))
        elif isinstance(other, (bytes, bytearray)):
            other = CScriptOp.encode_op_pushdata(other)
        return other

    def __add__(self, other):
        # Do the coercion outside of the try block so that errors in it are
        # noticed.
        other = self.__coerce_instance(other)

        try:
            # bytes.__add__ always returns bytes instances unfortunately
            return CScript(super(CScript, self).__add__(other))
        except TypeError:
            raise TypeError('Can not add a %r instance to a CScript' % other.__class__)

    def join(self, iterable):
        # join makes no sense for a CScript()
        raise NotImplementedError

    def __new__(cls, value=b''):
        if isinstance(value, bytes) or isinstance(value, bytearray):
            return super(CScript, cls).__new__(cls, value)
        else:
            def coerce_iterable(iterable):
                for instance in iterable:
                    yield cls.__coerce_instance(instance)
            # Annoyingly on both python2 and python3 bytes.join() always
            # returns a bytes instance even when subclassed.
            return super(CScript, cls).__new__(cls, b''.join(coerce_iterable(value)))

    def raw_iter(self):
        """Raw iteration

        Yields tuples of (opcode, data, sop_idx) so that the different possible
        PUSHDATA encodings can be accurately distinguished, as well as
        determining the exact opcode byte indexes. (sop_idx)