Python byte buffer object?

Is there a byte buffer object in Python to which I can append values of specific types? (preferably with specifiable endianess)

For example:

buf.add_int(4)    # should add a 4 byte integer
buf.add_short(10) # should add a 2 byte short
buf.add_byte(24)  # should add a byte

I know that I could just use开发者_Python百科 struct.pack but this approach just seems easier. Ideally it should be like the DataOutputStream and DataInputStream objects in Java which do this exact task.

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You can always use bitstring. It is capable of doing all the things you ask and more.

>>> import bitstring
>>> stream=bitstring.BitStream()
>>> stream.append("int:32=4")
>>> stream.append("int:16=10")
>>> stream.append("int:8=24")
>>> stream
BitStream('0x00000004000a18')
>>> stream.bytes
'\x00\x00\x00\x04\x00\n\x18'

Here is a link to the documentation.

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As Kark Knechtel suggests you'll have to make your own type that handles this. Here's a quick extension of bytearray:

import struct

class DataStream(bytearray):

    def append(self, v, fmt='>B'):
        self.extend(struct.pack(fmt, v))

>>> x = DataStream()
>>> x.append(5)
>>> x
bytearray(b'\x05')
>>> x.append(-1, '>i')
>>> x
bytearray(b'\x05\xff\xff\xff\xff')

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Just wrap up the struct.pack logic in your own class.