Buffer (ABC type) ponyfill for Python 3.11 and older

_abc_bufferlike.py

"""*BufferLike*, a quasi-ponyfill for collections.abc.Buffer

When collections.abc.Buffer is available, exports it directly.
Otherwise, crudely constructs an Abstract Base Class via mass ABC.register().
May not be suitable for all use-cases."""

try:
    # version_info >= (3, 12)
    from collections.abc import Buffer as BufferLike
except ImportError:
    # version_info < (3, 12)
    import abc
    import array
    import collections.abc
    import ctypes
    import mmap

    class BufferLike(collections.abc.ByteString):
        pass

    BufferLike.register(array.array)
    BufferLike.register(ctypes.Array)
    BufferLike.register(memoryview)
    BufferLike.register(mmap.mmap)

    # Bonus Library Support:

    # * CFFI:
    try:
        import cffi
    except ImportError:
        pass
    else:
        if hasattr(cffi.FFI, 'buffer') and isinstance(cffi.FFI.buffer, type):
            BufferLike.register(cffi.FFI.buffer)
        else:
            _ffi = cffi.FFI()
            if isinstance(_ffi.buffer, type):
                BufferLike.register(_ffi.buffer)
            else:
                with _ffi.new('uint8_t[0]') as _cdata:
                    _cdata_buf = _ffi.buffer(_cdata)
                    _ffi_buffer = _cdata_buf.__class__
                BufferLike.register(_ffi_buffer)
 
    # * NumPy:
    try:
        import numpy
    except ImportError:
        pass
    else:
        BufferLike.register(numpy.ndarray)
        
    # * bitarray
    try:
        import bitarray
    except ImportError:
        pass
    else:
        BufferLike.register(bitarray.bitarray)


__all__ = ['BufferLike']

_union_bufferlike.py

"""*BufferLike*, a quasi-ponyfill for collections.abc.Buffer

When collections.abc.Buffer is available, exports it directly.
Otherwise, crudely constructs an Abstract Base Class via mass typing.Union[].
May not be suitable for all use-cases."""

try:
    # version_info >= (3, 12)
    from collections.abc import Buffer as BufferLike
except ImportError:
    # version_info < (3, 12)
    import abc
    import array
    import collections.abc
    import ctypes
    import mmap
    from typing import Union

    BufferLike = Union[collections.abc.ByteString, array.array, ctypes.Array, memoryview, mmap.mmap]

    # Bonus Library Support:

    # * CFFI:
    try:
        import cffi
    except ImportError:
        pass
    else:
        if hasattr(cffi.FFI, 'buffer') and isinstance(cffi.FFI.buffer, type):
            BufferLike = Union[BufferLike, cffi.FFI.buffer]
        else:
            _ffi = cffi.FFI()
            if isinstance(_ffi.buffer, type):
                BufferLike = Union[BufferLike, _ffi.buffer]
            else:
                with _ffi.new('uint8_t[0]') as _cdata:
                    _cdata_buf = _ffi.buffer(_cdata)
                    _ffi_buffer = _cdata_buf.__class__
                BufferLike = Union[BufferLike, _ffi_buffer]
 
    # * NumPy:
    try:
        import numpy
    except ImportError:
        pass
    else:
        BufferLike = Union[BufferLike, numpy.ndarray]
        
    # * bitarray
    try:
        import bitarray
    except ImportError:
        pass
    else:
        BufferLike = Union[BufferLike, bitarray.bitarray]


__all__ = ['BufferLike']