Introduction

This repo is part of the tutorial found in https://github.com/ActivisionGameScience/ags_conda_recipes.git

It contains a single python module, ags_py_blosc_wrapper, that is a wrapper around the C++ library ags_blosc_wrapper (see https://github.com/ActivisionGameScience/ags_example_cpp_lib.git).

The purpose of this module is to demonstrate some techniques:

• How to manage external dependencies using conda
• How to call a C binary from python using cffi

We purposefully exposed both a C and C++ API in ags_blosc_wrapper to ease binding to other languages. In our opinion this is always the method to use. We recommend against trying to bind to C++ directly.

Either cffi or cython can be used for the C binding (we prefer cffi slightly).

How to build

The conda build recipe is located in https://github.com/ActivisionGameScience/ags_conda_recipes.git. You can use it to build, publish, and install the conda way.

However, you can also build and install this module by hand. Assuming that ags_blosc_wrapper is installed in the following location:

/some/path/lib/libags_blosc_wrapper.so

and PYTHONPATH points into a subdirectory:

/some/path/lib/python2.7/site-packages

you can build and install with the following commands:

git clone https://github.com/ActivisionGameScience/ags_example_py_wrapper.git
cd ags_example_py_wrapper
python setup.py install

The only reason that the module needs to be installed underneath the same lib directory is that the binary loading logic is dumb (it climbs the directory tree until it finds the file).

Here is an example of how to import and use the module:

from ags_py_blosc_wrapper import BloscWrapper
b = BloscWrapper()

# initialize data however you want
data = np.array(..., dtype=float32) # can be an arbitrary numpy array, not just floats

# compress data
data_compressed = b.compress(data)
del data

# do stuff

# decompress
data = b.decompress(data_compressed).view(np.float32)
del data_compressed

print(data)  # should be the same as it was originally

License

All files are licensed under the BSD 3-Clause License as follows:

Copyright (c) 2015, Activision Publishing, Inc.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.