Skip to main content

StarStruct allows for easy binary stream pack/unpack

Project description

Build Status
Coverage Status
Scrutinizer Code Quality

StarStruct

A package that provides consistent packing and unpacking of binary data

Getting Started

Requirements

  • Python 3.5+

Installation

StarStruct can be installed with pip:

$ pip install starstruct

or directly from the source code:

$ git clone https://github.com/sprout42/StarStruct.git
$ cd StarStruct
$ python setup.py install

Basic Usage

After installation, the package can imported:

$ python
>>> import starstruct
>>> starstruct.__version__

An example of the package can be seen below

import enum

# Import the package
from starstruct import Mode
from starstruct.message import Message

# A custom Enum you might be using
class MyEnum(enum.Enum):
    my_custom_data_type = 0x0
    my_other_data_type = 0x1
    final_data_type = 0x2

SizeOfData = Message('Data', [('pad', '8x')], Mode.Big)
AnotherDataSize = Message('Data', [
    ('status', 'H'),
    ('pad', '6x'),
], Mode.Big)

# Create your Message
MyMessage = Message('message_name', [
    ('an_important_integer', 'i'),                    # Pack it into the size of a struct integer
    ('ten_long_string', '10s'),                       # Pack it like 10 consecutive characters
    ('a_fixed_point_number', 'F', 'i', 4),            # Pack it in the size of an integer, but with four bits of precision
                                                      # as a floating point number
    ('union_identifier', 'B', MyEnum),
    ('like_a_c_union', {
        MyEnum.my_custom_data_type: SizeOfData,       # These sizes should usually all be the same,
        MyEnum.my_other_data_type: AnotherDataSize,   # but they can be of different styles!
        MyEnum.final_data_type: SizeOfData,
    }, 'union_identifier'),                           # Choose which type of thing based on union_identifier
], Mode.Big)                                          # Pack it with big endianess

# Now you can use a dictionary to make your messages
data_1 = {
    'an_important_integer': 42,
    'ten_long_string': 'wow! stuff',
    'a_fixed_point_number': '1.25',
    'union_identifier': MyEnum.my_other_data_type,
    'like_a_c_union': {'status': 1}
}

named_tuple_version = MyMessage.make(data_1)
print(named_tuple_version.an_important_integer)  # 42
print(named_tuple_version.a_fixed_point_number)  # b'\x00\x00\x00\x14'

packed_message = MyMessage.pack(data_1)
print(packed_message)  # b'\x00\x00\x00*wow! stuff\x00\x00\x00\x14\x01\x00\x01\x00\x00\x00\x00\x00\x00'

unpacked_message = MyMessage.unpack(packed_message)
print(unpacked_message.an_important_integer)  # 42
print(unpacked_message.a_fixed_point_number)  # 1.25

# -----------------------
# Variable sized messages
# -----------------------

RepeatedMessage = Message('Repeated', [
    ('x', 'B'),
    ('y', 'H'),
])

VariableMessage = Message('variable_message', [
    ('length_in_objects', 'H', 'message_data'),             # length field, in terms of message objects
    ('message_data', RepeatedMessage, 'length_in_objects'),  # variable message length data
    (b'length_in_bytes', 'B', 'bytes_data'),                # length field, in terms of packed bytes
    ('bytes_data', RepeatedMessage, b'length_in_bytes'),    # variable bytes length data
    ('repeated_data', RepeatedMessage, 3),                  # fixed length repeated message
], Mode.Little)

variable_data = {
    'length_in_objects': 2,  # Two objects long
    'message_data': [
        {'x': 5, 'y': 6},    # Object number 1
        {'x': 9, 'y': 1},    # Object number 2
    ],
    'length_in_bytes': 12,    # Each object is 3 bytes long, so 4 objects
    'bytes_data': [
        {'x': 0, 'y': 8},    # Object number 1, bytes 0 - 2
        {'x': 1, 'y': 9},    # Object number 2, bytes 3 - 5
        {'x': 2, 'y': 0},    # Object number 3, bytes 6 - 8
        {'x': 6, 'y': 2},    # Object number 4, bytes 9 - 11
    ],
    'repeated_data': [       # No length field specified required. Just the messages
        {'x': 1, 'y': 9},
        {'x': 1, 'y': 9},
        {'x': 0, 'y': 5},
    ],
}

named_tuple_version = VariableMessage.make(variable_data)
print(named_tuple_version.length_in_objects)               # 2
print(named_tuple_version.length_in_bytes)                 # 12
print(named_tuple_version.bytes_data)                      # [Repeated(x=0, y=8),
                                                           # Repeated(x=1, y=9),
                                                           # Repeated(x=2, y=0),
                                                           # Repeated(x=6, y=2)]

packed_message = VariableMessage.pack(**variable_data)
print(packed_message)                                      # b' x02 x00 x05 x06 x00 t x01 x00 \
                                                           # x0c x00 x08 x00 x01 t x00 x02 \
                                                           # x00 x00 x06 x02 x00 x01 t x00 \
                                                           # x01 t x00 x00 x05 x00'

unpacked_message = VariableMessage.unpack(packed_message)
print(unpacked_mesage.length_in_objects)                   # 2
print(unpacked_mesage.length_in_bytes)                     # 12
print(unpacked_mesage.bytes_data)                          # [Repeated(x=0, y=8),
                                                           # Repeated(x=1, y=9),
                                                           # Repeated(x=2, y=0),
                                                           # Repeated(x=6, y=2)]

Revision History

0.0.0 (YYYY/MM/DD)

  • TBD

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
StarStruct-0.9.1-py3-none-any.whl (38.8 kB) Copy SHA256 hash SHA256 Wheel py3
StarStruct-0.9.1.tar.gz (24.3 kB) Copy SHA256 hash SHA256 Source None

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN SignalFx SignalFx Supporter DigiCert DigiCert EV certificate StatusPage StatusPage Status page