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Description:

binobj 0.11.4

A cross-platform Python 3 library for reading and writing structured binary data
in an object-oriented (ish) style.

Why use binobj?
You may have used Python’s built-in struct library to load and dump binary
data. It’s unwieldy for larger or more complex data structures, and the format
strings are easy to get wrong. binobj is different in that it takes a class-based
approach to declaring binary structures.
Take a look at this example using struct:
data = (b'BM', 1024, 0, 12, 40, 32, 32, 1, 1, 0, 0, 72, 72, 2, 2)
header_bytes = struct.pack('<2sIIIIiiHHIIiiII', *data)
loaded = struct.unpack('<2sIIIIiiHHIIiiII', header_bytes)
n_pixels = loaded[5] * loaded[6]
The same example rewritten using binobj:
class BMP(binobj.Struct):
class Meta:
argument_defaults = {
"endian": "little"
}

magic: Bytes = b"BM"
file_size: UInt32
_reserved: binobj.Bytes(const=b"\0\0\0\0", discard=True)
pixels_offset: UInt32()

# Legacy DIB header
header_size: UInt32 = 40
image_width: Int32
image_height: Int32
n_color_planes: UInt16
n_bits_per_pixel: UInt16
compression_method: UInt32 = 0
bitmap_size: UInt32
v_resolution: Int32
h_resolution: Int32
n_palette_colors: UInt32
n_important_colors: UInt32

bmp = BMP(file_size=1024, pixels_offset=12, image_width=32, image_height=32, ...)
header_bytes = bytes(bmp)
loaded = BMP.from_bytes(header_bytes)
n_pixels = loaded.image_width * loaded.image_height
binobj also has other advantages in that it supports strings in any encoding
Python supports, toggling endianness on a per-field basis (necessary for ISO 9660
images), a variety of integer encodings, computed fields, validation, and more.

System Requirements

This package will not work on a mixed-endian system. Those are pretty rare
nowadays so chances are you won’t have a problem.
This has been tested on CPython 3.7-3.11, PyPy 3.7-3.9.

Installation
You can install this with pip like so:
pip3 install binobj

Be sure to use pip3 and not pip, because pip defaults to Python 2.
If you get a “Permission Denied” error, try:

pip3 install --user binobj
Side note: Don’t use sudo (even sudo -EH) to force a package to install,
as that’s a security risk. See this answer
on Stack Overflow to find out why.

Testing and Development
This package uses Tox to run tests on
multiple versions of Python.

Setup
To set up your development environment, you’ll need to install a few things.

For Python version management, I use pyenv-virtualenv.
Follow the installation instructions there.
You’ll also need make. Depending on your platform you can install it in
one of several ways:

macOS: brew install make
Debian systems (e.g. Ubuntu): sudo apt-get install make
Windows: Use Cygwin and install it during setup.

Once you have those installed, in the root directory of this repo run:
make setup

Running the Tests
To run the unit tests for all supported versions of Python, run make test.
The environments will automatically be rebuilt if needed.

Issues and Feature Requests
To report an issue, request a feature, or propose a change, please file a
report on the project’s GitHub page here.

License
I’m releasing this under the terms of the 3-Clause BSD License. For the full
legal text, see LICENSE.txt in the repository.