How to use bitstring - 10 common examples

self._rawarray.append(joinval)
            self._rawarray.extend(store._rawarray[1:])
        else:
            self._rawarray.extend(store._rawarray)
        self.bitlength += store.bitlength

    @property
    def byteoffset(self):
        return self.offset // 8

    @property
    def rawbytes(self):
        return self._rawarray


class ByteStore(ConstByteStore):
    __slots__ = ()

    def setbit(self, pos):
        assert 0 <= pos < self.bitlength
        byte, bit = divmod(self.offset + pos, 8)
        self._rawarray[byte] |= (128 >> bit)

    def unsetbit(self, pos):
        assert 0 <= pos < self.bitlength
        byte, bit = divmod(self.offset + pos, 8)
        self._rawarray[byte] &= ~(128 >> bit)

    def invertbit(self, pos):
        assert 0 <= pos < self.bitlength
        byte, bit = divmod(self.offset + pos, 8)
        self._rawarray[byte] ^= (128 >> bit)

def set_uint(self, value, nbits, bitpos):
        import bitstring
        if nbits // NBITS_PER_BYTE == 0:
            bins = bitstring.Bits(uint=value, length=nbits)
        else:
            bins = bitstring.Bits(uintbe=value, length=24)
        self.bit_stream[bitpos: bitpos + nbits] = bins

def _setbytes_safe(self, data, length=None, offset=0):
        """Set the data from a string."""
        data = bytearray(data)
        if length is None:
            # Use to the end of the data
            length = (len(data) - (offset // 8)) * 8 - offset
            self._datastore = ByteStore(data, length, offset)
        else:
            if length + offset > len(data) * 8:
                msg = "Not enough data present. Need {0} bits, have {1}."
                raise bitstring.CreationError(msg, length + offset, len(data) * 8)
            if not length:
                self._datastore = ByteStore(bytearray(0))
            else:
                self._datastore = ByteStore(data, length, offset)

if auto is not None:
            self._initialise_from_auto(auto, length, offset)
            return
        if not kwargs:
            # No initialisers, so initialise with nothing or zero bits
            if length is not None and length != 0:
                data = bytearray((length + 7) // 8)
                self._setbytes_unsafe(data, length, 0)
                return
            self._setbytes_unsafe(bytearray(0), 0, 0)
            return
        k, v = kwargs.popitem()
        try:
            init_without_length_or_offset[k](self, v)
            if length is not None or offset is not None:
                raise bitstring.CreationError("Cannot use length or offset with this initialiser.")
        except KeyError:
            try:
                init_with_length_only[k](self, v, length)
                if offset is not None:
                    raise bitstring.CreationError("Cannot use offset with this initialiser.")
            except KeyError:
                if offset is None:
                    offset = 0
                try:
                    init_with_length_and_offset[k](self, v, length, offset)
                except KeyError:
                    raise bitstring.CreationError("Unrecognised keyword '{0}' used to initialise.", k)

def _readuint(self, length, start):
        """Read bits and interpret as an unsigned int."""
        if not length:
            raise bitstring.InterpretError("Cannot interpret a zero length bitstring "
                                           "as an integer.")
        offset = self._offset
        startbyte = (start + offset) // 8
        endbyte = (start + offset + length - 1) // 8

        b = binascii.hexlify(bytes(self._datastore.getbyteslice(startbyte, endbyte + 1)))
        if not b:
            return 0
        i = int(b, 16)
        final_bits = 8 - ((start + offset + length) % 8)
        if final_bits != 8:
            i >>= final_bits
        i &= (1 << length) - 1
        return i

def _readuintle(self, length, start):
        """Read bits and interpret as a little-endian unsigned int."""
        if length % 8:
            raise bitstring.InterpretError("Little-endian integers must be whole-byte. "
                                 "Length = {0} bits.", length)
        assert start + length <= self.len
        absolute_pos = start + self._offset
        startbyte, offset = divmod(absolute_pos, 8)
        val = 0
        if not offset:
            endbyte = (absolute_pos + length - 1) // 8
            chunksize = 4 # for 'L' format
            while endbyte - chunksize + 1 >= startbyte:
                val <<= 8 * chunksize
                val += struct.unpack('

def _readoct(self, length, start):
        """Read bits and interpret as an octal string."""
        if length % 3:
            raise bitstring.InterpretError("Cannot convert to octal unambiguously - "
                                 "not multiple of 3 bits.")
        if not length:
            return ''
        # Get main octal bit by converting from int.
        # Strip starting 0 or 0o depending on Python version.
        end = oct(self._readuint(length, start))[LEADING_OCT_CHARS:]
        if end.endswith('L'):
            end = end[:-1]
        middle = '0' * (length // 3 - len(end))
        return middle + end

def _readhex(self, length, start):
        """Read bits and interpret as a hex string."""
        if length % 4:
            raise bitstring.InterpretError("Cannot convert to hex unambiguously - "
                                           "not multiple of 4 bits.")
        if not length:
            return ''
        # This monstrosity is the only thing I could get to work for both 2.6 and 3.1.
        # TODO: Optimize: This really shouldn't call __getitem__.
        # TODO: Is utf-8 really what we mean here?
        s = str(binascii.hexlify(self[start:start + length].tobytes()).decode('utf-8'))
        # If there's one nibble too many then cut it off
        return s[:-1] if (length // 4) % 2 else s

def _setbytes_safe(self, data, length=None, offset=0):
        """Set the data from a string."""
        data = bytearray(data)
        if length is None:
            # Use to the end of the data
            length = (len(data) - (offset // 8)) * 8 - offset
            self._datastore = ByteStore(data, length, offset)
        else:
            if length + offset > len(data) * 8:
                msg = "Not enough data present. Need {0} bits, have {1}."
                raise bitstring.CreationError(msg, length + offset, len(data) * 8)
            if not length:
                self._datastore = ByteStore(bytearray(0))
            else:
                self._datastore = ByteStore(data, length, offset)

raise bitstring.CreationError("The offset keyword isn't applicable to this initialiser.")
        if isinstance(s, basestring):
            bs = self._converttobitstring(s)
            assert bs._offset == 0
            self._setbytes_unsafe(bs._datastore.rawbytes, bs.length, 0)
            return
        if isinstance(s, (bytes, bytearray)):
            self._setbytes_unsafe(bytearray(s), len(s) * 8, 0)
            return
        if isinstance(s, numbers.Integral):
            # Initialise with s zero bits.
            if s < 0:
                msg = "Can't create bitstring of negative length {0}."
                raise bitstring.CreationError(msg, s)
            data = bytearray((s + 7) // 8)
            self._datastore = ByteStore(data, s, 0)
            return
        if isinstance(s, collections.Iterable):
            # Evaluate each item as True or False and set bits to 1 or 0.
            self._setbin_unsafe(''.join(str(int(bool(x))) for x in s))
            return
        raise TypeError("Cannot initialise bitstring from {0}.".format(type(s)))