Change log
==========

**3.6.1** (2025-08-12):

* add development files for statistical tests in ``devel/random/``
* optimize ``util.sum_indices()``
* fix RecursionError in ``util.random_k()``, see `#239 <https://github.com/ilanschnell/bitarray/issues/239>`__
* add ``devel/test_sum_indices.py``


**3.6.0** (2025-07-29):

* add ``util.random_k()``, see `#237 <https://github.com/ilanschnell/bitarray/issues/237>`__
* add ``util.sum_indices()``
* optimize ``util.xor_indices()``
* move development files from ``examples/`` to ``devel/``


**3.5.2** (2025-07-21):

* optimize ``util.random_p()`` by also using bitwise AND in final step
* fix DeprecationWarning regarding ``u`` type code
* add `verification tests <../devel/test_random.py>`__ for internals
  of ``util.random_p()``


**3.5.1** (2025-07-14):

* optimize ``util.random_p()`` for ``n < 100``
* add `Random Bitarrays <random_p.rst>`__ documentation
* add `statistical tests for random functions <../devel/test_random.py>`__


**3.5.0** (2025-07-06):

* add ``util.random_p()``
* improve sparse compression testing


**3.4.3** (2025-06-23):

* minor updates to documentation
* C-level:
    - simplify and speedup ``extend_unicode01()``
    - customize ``resize_lite()`` - avoid unused code
    - use ``PyTypeObject`` for bitarray type object in ``_util.c`` to
      be consistent with ``_bitarray.c``
    - add and improve comments to implementation of sparse bitarray
      compression
    - simplify ``sc_count()``


**3.4.2** (2025-05-21):

* extend documentation of
  `compression of sparse bitarrays <sparse_compression.rst>`__
* ``util.sc_decode()`` and ``util.vl_decode()`` now raise ``StopIteration``
  instead of ``ValueError`` when unexpected end of stream is encountered
* add debug mode tests for ``read_n()``, ``write_n()`` and ``count_from_word()``


**3.4.1** (2025-05-15):

* add ``pyproject.toml``, see `#233 <https://github.com/ilanschnell/bitarray/issues/233>`__
* implement ``bits2bytes()`` in C
* optimize ``delslice()`` when ``step`` is larger than about 5
* consistently name ``*_span()`` and ``*_range()`` in C for
  invert, set and count
* organize and add tests (including debug mode tests for ``zlw()``)


**3.4.0** (2025-05-06):

* remove ``.endian()`` method in favor of data descriptor ``.endian``
* allow bitarray initializer ``bytes`` or ``bytearray`` to set buffer directly
* allow calling ``.extend()`` with ``bytes`` object (although the only
  valid bytes are 0x00 and 0x01)
* add ``util.byteswap()``
* add ``util.correspond_all()``
* fix ``.reverse()`` for imported buffer
* drop Python 3.5 support
* add tests


**3.3.2** (2025-05-02):

* fix off-by-one-error in check for length of count argument
  in ``util.canonical_decode()``
* simplify ``util.int2ba()``
* add tests
* add `masked indexing example <../examples/masked.py>`__
* add `tricks example <../devel/tricks.py>`__


**3.3.1** (2025-04-04):

* remove ``License`` classifier in favor of a SPDX license expression, `#231 <https://github.com/ilanschnell/bitarray/issues/231>`__
* reorganize and cleanup many tests


**3.3.0** (2025-03-30):

* add optional ``group`` and ``sep`` arguments' to ``.to01()``, `#230 <https://github.com/ilanschnell/bitarray/issues/230>`__ -
  as well as ``util.ba2hex()`` and ``util.ba2base()``
* ignore whitespace in ``util.base2ba()`` and ``util.hex2ba()``
* check for embedded nul characters when extending (and initializing)
  bitarray from string
* improve testing
* add `double precision floating point number example <../examples/double.py>`__


**3.2.0** (2025-03-19):

* add ``util.xor_indices()``, `#229 <https://github.com/ilanschnell/bitarray/issues/229>`__
* add `Hamming code example <../examples/hamming.py>`__


**3.1.1** (2025-03-06):

* updated ``pythoncapi_compat.h`` for pypy3.11 support, see `#227 <https://github.com/ilanschnell/bitarray/issues/227>`__
* use ``__builtin_parityll()`` when available in ``util.parity()``
* add ``parity_64()`` to header
* simplify some tests
* add `LFSR example <../examples/lfsr.py>`__


**3.1.0** (2025-02-19):

* allow mask assignment to bitarrays, see `#225 <https://github.com/ilanschnell/bitarray/issues/225>`__
* add missing masked operations to pyi-file
* refactor ``resize()`` and avoid overallocation when downsizing buffer
* update ``build_wheels.yml``
* fix some typos
* minor simplifications
* rename ``growth/`` example to ``resize/`` and add tests for ``resize()``
* update gene example
* add comments


**3.0.0** (2024-10-15):

* see `Bitarray 3 transition <bitarray3.rst>`__
* remove Python 2.7 support
* ``.decode()`` now returns iterator (equivalent to past ``.iterdecode()``)
* ``.search()`` now returns iterator (equivalent to past ``.itersearch()``)
* remove ``.iterdecode()`` and ``.itersearch()``
* remove ``util.rindex()``, use ``.index(..., right=1)`` instead,
  deprecated since 2.9
* remove ``util.make_endian()``, use ``bitarray(..., endian=...)`` instead,
  deprecated since 2.9
* remove hackish support for ``bitarray()`` handling unpickling,
  see detailed explaination in `#207 <https://github.com/ilanschnell/bitarray/issues/207>`__ - closes `#206 <https://github.com/ilanschnell/bitarray/issues/206>`__


**2.9.3** (2024-10-10):

* add official Python 3.13 support
* update cibuildwheel to 2.21.3
* minor simplifications
* fix some typos


**2.9.2** (2024-01-01):

* optimize initialization from strings by not constantly resizing buffer
* optimize ``util.hex2ba()`` and ``util.base2ba()`` by avoiding unnecessary
  copies
* optimize ``util.base2ba()`` and ``util.ba2base()`` for ``n=16`` (hexadecimal)


**2.9.1** (2023-12-23):

* avoid buffer being unnecessarily initialized with 0s in several
  functions of the ``bitarray.util`` module
* fix ``.count()`` type hint in pyi-file
* improve testing


**2.9.0** (2023-12-17):

* deprecate support for Python 2 - Python 2.7 support will be removed
  in bitarray version 3.0,
  see `roadmap <https://github.com/ilanschnell/bitarray#roadmap>`__
* ``bitarray(n)`` for integer initializer ``n`` will always return a bitarray
  of length ``n`` with all items initialized to ``0``, see `#212 <https://github.com/ilanschnell/bitarray/issues/212>`__
* allow sub-bitarray in ``.count()``, `#212 <https://github.com/ilanschnell/bitarray/issues/212>`__
* add ``util.ones()``
* ``.find()`` and ``.index()``: add keyword argument ``right`` for rightmost index
* ``.itersearch()``: add start and stop argument, and keyword
  argument ``right`` (for descending order - starting with rightmost match)
* deprecate ``util.rindex()`` (will be removed in 3.0 release),
  use ``.index(..., right=True)`` instead
* deprecate ``util.make_endian()`` (will be removed in 3.0 release),
  use ``bitarray(..., endian=...)`` instead


**2.8.5** (2023-12-09):

* speedup unaligned copies by always using word shifts (in combination
  with builtin byte swap 64 when available) when bit-endianness and
  machine byte-order are opposite
* add ``HAVE_BUILTIN_BSWAP64`` to header
* avoid misaligned pointers when casting to ``(uint64_t *)``
* add tests


**2.8.4** (2023-12-04):

* simplify ``copy_n()`` (remove special cases), see `#d2d6fd53 <https://github.com/ilanschnell/bitarray/commit/d2d6fd53>`__
* add `word shift example C program <../devel/shift_r8.c>`__,
  and simplify ``shift_r8()``
* improve documentation and testing
* add `roadmap <https://github.com/ilanschnell/bitarray#roadmap>`__


**2.8.3** (2023-11-11):

* ensure readonly attribute is set correctly when creating new objects,
  see `#211 <https://github.com/ilanschnell/bitarray/issues/211>`__
* optimize sparse bitarray compression for raw block type
* improve hash functions in Bloom filter example


**2.8.2** (2023-10-03):

* update cibuildwheel to 2.16.1 in order to provide cp312 wheels on PyPI
* improve error messages for masked assignment
* simplify test collection
* added ``pytest.ini`` to allow running pytest with no additional arguments,
  see `#208 <https://github.com/ilanschnell/bitarray/issues/208>`__
* ``util.sc_encode()``: avoid writing empty blocks at end of compressed
  stream, i.e. skip encoding when total population count is reached


**2.8.1** (2023-08-06):

* use reconstructor function for pickling, see `#207 <https://github.com/ilanschnell/bitarray/issues/207>`__
* simplify implementation of ``.reverse()``


**2.8.0** (2023-07-22):

* allow `integer sequence indexing <indexing.rst>`__ by list of indices,
  see `#204 <https://github.com/ilanschnell/bitarray/issues/204>`__ (addresses `#156 <https://github.com/ilanschnell/bitarray/issues/156>`__ and `#190 <https://github.com/ilanschnell/bitarray/issues/190>`__)
* add `masked indexing <indexing.rst>`__ by bitarray masks,
  see `#205 <https://github.com/ilanschnell/bitarray/issues/205>`__ (addresses `#190 <https://github.com/ilanschnell/bitarray/issues/190>`__)
* improve ``.bytereverse()`` docstring, see issue `#202 <https://github.com/ilanschnell/bitarray/issues/202>`__


**2.7.6** (2023-06-24):

* remove caching hash value, fixes issue `#201 <https://github.com/ilanschnell/bitarray/issues/201>`__


**2.7.5** (2023-06-10):

* fix for pypy3.9-v7.3.11, `#198 <https://github.com/ilanschnell/bitarray/issues/198>`__ (fixes `#188 <https://github.com/ilanschnell/bitarray/issues/188>`__)
* enable building wheels for PyPy


**2.7.4** (2023-05-29):

* register ``bitarray`` as ``abc.MutableSequence``, see `#196 <https://github.com/ilanschnell/bitarray/issues/196>`__
* cibuildwheel: update macOS version to 11 from unsupported 10.15, see
  https://github.com/actions/runner-images/issues/5583
* improve documentation regarding type when indexing single
  bitarray items, `#192 <https://github.com/ilanschnell/bitarray/issues/192>`__


**2.7.3** (2023-02-20):

* fix popcount64 name conflict on NetBSD, `#189 <https://github.com/ilanschnell/bitarray/issues/189>`__
* even though PyPy is not actively supported, allow running tests for
  PyPy 3.7 and 3.8, see also `#188 <https://github.com/ilanschnell/bitarray/issues/188>`__
* allow running ``python setup.py test``
* add official Python 3.12 support
* simplify count functionality in util module
* retire ``bitcount_lookup[256]`` table
* improve ``util.count_n()`` error messages
* avoid ``util`` module tests from being run more than once in each
  call to ``bitarray.test()`` when called multiple times in the same
  Python process, see `#6e52e49a <https://github.com/ilanschnell/bitarray/commit/6e52e49a>`__
* improve testing


**2.7.2** (2023-02-12):

* speedup all count functionality by using ``__builtin_popcountll`` when
  available, see `#187 <https://github.com/ilanschnell/bitarray/issues/187>`__
* add ``popcount64()`` to ``bitarray.h`` - we assume now that ``uint64_t`` is
  always available
* improve testing


**2.7.1** (2023-02-10):

* optimize ``util.sc_encode()``


**2.7.0** (2023-02-05):

* add ``util.sc_encode()`` and ``util.sc_decode()`` for
  `compression of sparse bitarrays <sparse_compression.rst>`__
* add ``util.any_and()``
* add ``util.intervals()``
* move functionality of the following utility functions entirely to C:
  ``hex2ba()``, ``base2ba()``, ``deserialize()``, ``vl_decode()``, ``zeros()``
* improve error checking for unpickling
* add `distance metrics <../examples/distance.py>`__ example:
  dice, hamming, jaccard, kulczynski1, rogerstanimoto, russellrao,
  sokalmichener, sokalsneath, yule
* add example `sparse bitarray <../examples/sparse>`__ implementations


**2.6.2** (2023-01-01):

* optimize ``richcompare()`` for opposite endianness
* improve some docstrings add tests


**2.6.1** (2022-12-18):

* add documentation on shift operators, `#181 <https://github.com/ilanschnell/bitarray/issues/181>`__
* fix typo in iterable initializer description, `#179 <https://github.com/ilanschnell/bitarray/issues/179>`__
* optimize ``richcompare()``


**2.6.0** (2022-07-19):

* add data descriptors: ``.nbytes``, ``.padbits``, ``.readonly``
* allow optional ``endian`` argument to be ``None`` when creating bitarrays
* fix type annotation for ``canonical_decode()``, `#178 <https://github.com/ilanschnell/bitarray/issues/178>`__
* frozenbitarray's pad bits are now guaranteed to be zero
* add tests


**2.5.1** (2022-05-10):

* optimize ``.reverse()``, see `#177 <https://github.com/ilanschnell/bitarray/issues/177>`__
* allow negative (byte) indices in ``.bytereverse()``


**2.5.0** (2022-05-04):

* add calculating of canonical Huffman codes ``util.canonical_huffman()``
  and decoding thereof ``util.canonical_decode()``, see `#173 <https://github.com/ilanschnell/bitarray/issues/173>`__
* allow creating "Huffman codes" from frequency maps with a single symbol
  in ``util.huffman_code()`` and ``util.canonical_huffman()``, see `#172 <https://github.com/ilanschnell/bitarray/issues/172>`__
* allow bytes-like argument in ``.frombytes()`` and ``.pack()`` - previously,
  the arguments were limited to the ``bytes`` object, see `#174 <https://github.com/ilanschnell/bitarray/issues/174>`__
* allow bytes-like arguments in ``util.deserialize()``
* add official `pyodide <https://pyodide.org/>`__ support
* add `DEFLATE decompression <../examples/puff/>`__ example
* optimize ``.bytereverse()``
* optimize ``delslice()`` for cases like ``del a[1:17:2]`` when ``a`` is large
* fix ``examples/huffman/compress.py`` to handle files with 0 or 1 characters,
  see also `#172 <https://github.com/ilanschnell/bitarray/issues/172>`__
* add ``skipIf`` decorator for skipping tests
* add tests


**2.4.1** (2022-03-29):

* improve ``resize()``, see `#167 <https://github.com/ilanschnell/bitarray/issues/167>`__
* optimize ``copy_n()`` by avoiding loops, `#171 <https://github.com/ilanschnell/bitarray/issues/171>`__
* ``.bytereverse()`` no longer sets unused pad bits to zero


**2.4.0** (2022-03-01):

* enable building wheels for multiple platforms and Python versions using
  pypa/cibuildwheel, see `#165 <https://github.com/ilanschnell/bitarray/issues/165>`__ and `#170 <https://github.com/ilanschnell/bitarray/issues/170>`__ (thanks Brian Thorne, @hardbyte)
* use setuptools instead of distutils in ``setup.py``, `#168 <https://github.com/ilanschnell/bitarray/issues/168>`__
* add missing type hinting for ``.count()`` step argument


**2.3.7** (2022-02-21):

* add optional step argument to ``.count()`` method, see `#162 <https://github.com/ilanschnell/bitarray/issues/162>`__ and `#163 <https://github.com/ilanschnell/bitarray/issues/163>`__
* add tests


**2.3.6** (2022-02-07):

* add optional value parameter to ``util.count_n()``, see `#154 <https://github.com/ilanschnell/bitarray/issues/154>`__ and `#161 <https://github.com/ilanschnell/bitarray/issues/161>`__
* determine machine endianness at build time when possible, by using
  the ``PY_LITTLE_ENDIAN`` macro, in order to optimize ``shift_r8()``
* add official Python 3.11 support


**2.3.5** (2022-01-07):

* Fixed bug for big-endian systems (such as IBM s390), see `#159 <https://github.com/ilanschnell/bitarray/issues/159>`__ and `#160 <https://github.com/ilanschnell/bitarray/issues/160>`__
* Pass ``zip_safe=False`` to ``setup()``, see `#151 <https://github.com/ilanschnell/bitarray/issues/151>`__


**2.3.4** (2021-09-12):

* Fix ``util.ba2int()`` for frozenbitarrays.  A bug was introduced in 2.3.0
  as ``.tobytes()`` no longer treats pad bits for read-only buffers as zero.
* add tests


**2.3.3** (2021-09-05):

* improve some error messages
* add tests


**2.3.2** (2021-08-23):

* fix slice assignment for shared buffer with offset case, see `#3ba05687 <https://github.com/ilanschnell/bitarray/commit/3ba05687>`__
  and `#73081e98 <https://github.com/ilanschnell/bitarray/commit/73081e98>`__
* add tests (including internal debug mode tests for ``buffers_overlap()``)


**2.3.1** (2021-08-20):

* fix special shared buffer copy case, see `#815c2a11 <https://github.com/ilanschnell/bitarray/commit/815c2a11>`__
* add and improve tests


**2.3.0** (2021-08-15):

* add optional ``buffer`` argument to ``bitarray()`` to import the buffer of
  another object, `#141 <https://github.com/ilanschnell/bitarray/issues/141>`__, `#146 <https://github.com/ilanschnell/bitarray/issues/146>`__, see also: `buffer protocol <buffer.rst>`__
* update ``.buffer_info()`` to include: a read-only flag, an imported buffer
  flag, and the number of buffer exports
* add optional start and stop arguments to ``util.rindex()``
* add `memory-mapped file <../examples/mmapped-file.py>`__ example
* ignore underscore (``_``) in string input, e.g. ``bitarray('1100_0111')``
* add missing type hinting for new ``.bytereverse()`` arguments
* fix ``.extend()`` type annotations, `#145 <https://github.com/ilanschnell/bitarray/issues/145>`__
* avoid ``.reverse()`` using temporary memory
* make ``.unpack()``, ``util.serialize()``, ``util.vl_encode()``
  and ``.__reduce__()`` more memory efficient
* add and improve tests


**2.2.5** (2021-08-07):

* speedup ``find_bit()`` and ``find_last()`` using uint64 checking, this means
  a speedup for ``.find()``, ``.index()``, ``.search()`` and ``util.rindex()``
* add optional start and stop arguments to ``.bytereverse()``
* add example to illustrate how
  `unaligned copying <../devel/copy_n.py>`__ works internally
* add documentation
* add tests


**2.2.4** (2021-07-29):

* use shift operations to speedup all unaligned copy operations, `#142 <https://github.com/ilanschnell/bitarray/issues/142>`__
* expose functionality to Python level only in debug mode for testing
* add and improve tests


**2.2.3** (2021-07-22):

* speedup ``repeat()``, `#136 <https://github.com/ilanschnell/bitarray/issues/136>`__
* speedup shift operations, `#139 <https://github.com/ilanschnell/bitarray/issues/139>`__
* optimize slice assignment with negative step, e.g.: ``a[::-1] = 1``
* add tests


**2.2.2** (2021-07-16):

* speedup slice assignment, see `#132 <https://github.com/ilanschnell/bitarray/issues/132>`__ and `#135 <https://github.com/ilanschnell/bitarray/issues/135>`__
* speedup bitwise operations, `#133 <https://github.com/ilanschnell/bitarray/issues/133>`__
* optimize ``getbit()`` and ``setbit()`` in ``bitarray.h``
* fix TypeError messages when bitarray or int (0, 1) are expected (bool
  is a subclass of int)
* add and improve tests


**2.2.1** (2021-07-06):

* improve documentation
* speedup ``vl_encode()``
* ``bitarray.h``: make ``getbit()`` always an (inline) function
* add assertions in C code


**2.2.0** (2021-07-03):

* add ``bitarray.util.vl_encode()`` and ``bitarray.util.vl_decode()`` which
  uses a `variable length bitarray format <variable_length.rst>`__, `#131 <https://github.com/ilanschnell/bitarray/issues/131>`__


**2.1.3** (2021-06-15):

* Fix building with MSVC / Bullseye, `#129 <https://github.com/ilanschnell/bitarray/issues/129>`__


**2.1.2** (2021-06-13):

* support type hinting for all Python 3 versions (that bitarray supports,
  3.5 and higher currently), fixed `#128 <https://github.com/ilanschnell/bitarray/issues/128>`__
* add explicit endianness to two tests, fixes `#127 <https://github.com/ilanschnell/bitarray/issues/127>`__


**2.1.1** (2021-06-11):

* add type hinting (see PEP 484, 561) using stub (``.pyi``) files
* add tests


**2.1.0** (2021-05-05):

* add ``.find()`` method, see `#122 <https://github.com/ilanschnell/bitarray/issues/122>`__
* ``.find()``, ``.index()``, ``.search()`` and ``.itersearch()`` now all except
  both (sub-) bitarray as well as bool items to be searched for
* improve encode/decode error messages
* add `lexicographical permutations example <../examples/lexico.py>`__
* add tests


**2.0.1** (2021-04-19):

* update documentation
* improve some error messages


**2.0.0** (2021-04-14):

* require more specific objects, int (0 or 1) or bool, see `#119 <https://github.com/ilanschnell/bitarray/issues/119>`__
* items are always returned as int 0 or 1, `#119 <https://github.com/ilanschnell/bitarray/issues/119>`__
* remove ``.length()`` method (deprecated since 1.5.1 - use ``len()``)
* in ``.unpack()`` the ``one`` argument now defaults to 0x01 (was 0xff)
* ``.tolist()`` now always returns a list of integers (0 or 1)
* fix frozenbitarray hash function, see `#121 <https://github.com/ilanschnell/bitarray/issues/121>`__
* fix frozenbitarray being mutable by ``<<=`` and ``>>=``
* support sequence protocol in ``.extend()`` (and bitarray creation)
* improve OverflowError messages from ``util.int2ba()``
* add `hexadecimal example <../examples/hexadecimal.py>`__


**1.9.2** (2021-04-10):

* update pythoncapi_compat: Fix support with PyPy 3.7, `#120 <https://github.com/ilanschnell/bitarray/issues/120>`__
* update readme


**1.9.1** (2021-04-05):

* switch documentation from markdown to reStructuredText
* add tests


**1.9.0** (2021-04-03):

* add shift operations (``<<``, ``>>``, ``<<=``, ``>>=``), see `#117 <https://github.com/ilanschnell/bitarray/issues/117>`__
* add ``bitarray.util.ba2base()`` and ``bitarray.util.base2ba()``,
  see last paragraph in `Bitarray representations <represent.rst>`__
* documentation and tests


**1.8.2** (2021-03-31):

* fix crash caused by unsupported types in binary operations, `#116 <https://github.com/ilanschnell/bitarray/issues/116>`__
* speedup initializing or extending a bitarray from another with different
  bit-endianness
* add formatting options to ``bitarray.util.pprint()``
* add documentation on `bitarray representations <represent.rst>`__
* add and improve tests (all 291 tests run in less than half a second on
  a modern machine)


**1.8.1** (2021-03-25):

* moved implementation of and ``hex2ba()`` and ``ba2hex()`` to C-level
* add ``bitarray.util.parity()``


**1.8.0** (2021-03-21):

* add ``bitarray.util.serialize()`` and ``bitarray.util.deserialize()``
* allow whitespace (ignore space and ``\n\r\t\v``) in input strings,
  e.g. ``bitarray('01 11')`` or ``a += '10 00'``
* add ``bitarray.util.pprint()``
* When initializing a bitarray from another with different bit-endianness,
  e.g. ``a = bitarray('110', 'little')`` and ``b = bitarray(a, 'big')``,
  the buffer used to be simply copied, with consequence that ``a == b`` would
  result in ``False``.  This is fixed now, that is ``a == b`` will always
  evaluate to ``True``.
* add test for loading existing pickle file (created using bitarray 1.5.0)
* add example showing how to `jsonize bitarrays <../examples/extend_json.py>`__
* add tests


**1.7.1** (2021-03-12):

* fix issue `#114 <https://github.com/ilanschnell/bitarray/issues/114>`__, raise TypeError when incorrect index is used during
  assignment, e.g. ``a[1.5] = 1``
* raise TypeError (not IndexError) when assigning slice to incorrect type,
  e.g. ``a[1:4] = 1.2``
* improve some docstrings and tests


**1.7.0** (2021-02-27):

* add ``bitarray.util.urandom()``
* raise TypeError when trying to extend bitarrays from bytes on Python 3,
  i.e. ``bitarray(b'011')`` and ``.extend(b'110')``.  (Deprecated since 1.4.1)


**1.6.3** (2021-01-20):

* add missing .h files to sdist tarball, `#113 <https://github.com/ilanschnell/bitarray/issues/113>`__


**1.6.2** (2021-01-20):

* use ``Py_SET_TYPE()`` and ``Py_SET_SIZE()`` for Python 3.10, `#109 <https://github.com/ilanschnell/bitarray/issues/109>`__
* add official Python 3.10 support
* fix slice assignment to same object,
  e.g. ``a[2::] = a`` or ``a[::-1] = a``, `#112 <https://github.com/ilanschnell/bitarray/issues/112>`__
* add bitarray.h, `#110 <https://github.com/ilanschnell/bitarray/issues/110>`__


**1.6.1** (2020-11-05):

* use PyType_Ready for all types: bitarray, bitarrayiterator,
  decodeiterator, decodetree, searchiterator


**1.6.0** (2020-10-17):

* add ``decodetree`` object, for speeding up consecutive calls
  to ``.decode()`` and ``.iterdecode()``, in particular when dealing
  with large prefix codes, see `#103 <https://github.com/ilanschnell/bitarray/issues/103>`__
* add optional parameter to ``.tolist()`` which changes the items in the
  returned list to integers (0 or 1), as opposed to Booleans
* remove deprecated ``bitdiff()``, which has been deprecated since version
  1.2.0, use ``bitarray.util.count_xor()`` instead
* drop Python 2.6 support
* update license file, `#104 <https://github.com/ilanschnell/bitarray/issues/104>`__


**1.5.3** (2020-08-24):

* add optional index parameter to ``.index()`` to invert single bit
* fix ``sys.getsizeof(bitarray)`` by adding ``.__sizeof__()``, see issue `#100 <https://github.com/ilanschnell/bitarray/issues/100>`__


**1.5.2** (2020-08-16):

* add PyType_Ready usage, issue `#66 <https://github.com/ilanschnell/bitarray/issues/66>`__
* speedup search() for bitarrays with length 1 in sparse bitarrays,
  see issue `#67 <https://github.com/ilanschnell/bitarray/issues/67>`__
* add tests


**1.5.1** (2020-08-10):

* support signed integers in ``util.ba2int()`` and ``util.int2ba()``,
  see issue `#85 <https://github.com/ilanschnell/bitarray/issues/85>`__
* deprecate ``.length()`` in favor of ``len()``


**1.5.0** (2020-08-05):

* Use ``Py_ssize_t`` for bitarray index.  This means that on 32bit
  systems, the maximum number of elements in a bitarray is 2 GBits.
  We used to have a special 64bit index type for all architectures, but
  this prevented us from using Python's sequence, mapping and number
  methods, and made those method lookups slow.
* speedup slice operations when step size = 1 (if alignment allows
  copying whole bytes)
* Require equal endianness for operations: ``&``, ``|``, ``^``, ``&=``, ``|=``, ``^=``.
  This should have always been the case but was overlooked in the past.
* raise TypeError when trying to create bitarray from boolean
* This will be last release to still support Python 2.6 (which was retired
  in 2013).  We do NOT plan to stop support for Python 2.7 anytime soon.


**1.4.2** (2020-07-15):

* add more tests
* C-level:
    - simplify pack/unpack code
    - fix memory leak in ``~`` operation (bitarray_cpinvert)


**1.4.1** (2020-07-14):

* add official Python 3.9 support
* improve many docstrings
* add DeprecationWarning for ``bitdiff()``
* add DeprecationWarning when trying to extend bitarrays
  from bytes on Python 3 (``bitarray(b'011')`` and ``.extend(b'110')``)
* C-level:
    - Rewrote ``.fromfile()`` and ``.tofile()`` implementation,
      such that now the same code is used for Python 2 and 3.
      The new implementation is more memory efficient on
      Python 3.
    - use ``memcmp()`` in ``richcompare()`` to shortcut EQ/NE, when
      comparing two very large bitarrays for equality the
      speedup can easily be 100x
    - simplify how unpacking is handled
* add more tests


**1.4.0** (2020-07-11):

* add ``.clear()`` method (Python 3.3 added this method to lists)
* avoid over-allocation when bitarray objects are initially created
* raise BufferError when resizing bitarrays which is exporting buffers
* add example to study the resize() function
* improve some error messages
* add more tests
* raise ``NotImplementedError`` with (useful message) when trying to call
  the ``.fromstring()`` or ``.tostring()`` methods, which have been removed
  in the last release


**1.3.0** (2020-07-06):

* add ``bitarray.util.make_endian()``
* ``util.ba2hex()`` and ``util.hex2ba()`` now also support little-endian
* add ``bitarray.get_default_endian()``
* made first argument of initializer a positional-only parameter
* remove ``.fromstring()`` and ``.tostring()`` methods, these have been
  deprecated 8 years ago, since version 0.4.0
* add ``__all__`` in ``bitarray/__init__.py``
* drop Python 3.3 and 3.4 support


**1.2.2** (2020-05-18):

* ``util.ba2hex()`` now always return a string object (instead of bytes
  object for Python 3), see issue `#94 <https://github.com/ilanschnell/bitarray/issues/94>`__
* ``util.hex2ba`` allows a unicode object as input on Python 2
* Determine 64-bitness of interpreter in a cross-platform fashion `#91 <https://github.com/ilanschnell/bitarray/issues/91>`__,
  in order to better support PyPy


**1.2.1** (2020-01-06):

* simplify markdown of readme so PyPI renders better
* make tests for bitarray.util required (instead of warning when
  they cannot be imported)


**1.2.0** (2019-12-06):

* add bitarray.util module which provides useful utility functions
* deprecate ``bitarray.bitdiff()`` in favor of ``bitarray.util.count_xor()``
* use markdown for documentation
* fix bug in ``.count()`` on 32bit systems in special cases when array size
  is 2^29 bits or larger
* simplified tests by using bytes syntax
* update smallints and sieve example to use new utility module
* simplified mandel example to use numba
* use file context managers in tests


**1.1.0** (2019-11-07):

* add frozenbitarray object
* add optional start and stop arguments to ``.count()`` method
* add official Python 3.8 support
* optimize ``setrange()`` (C-function) by using ``memset()``
* fix issue `#74 <https://github.com/ilanschnell/bitarray/issues/74>`__, bitarray is hashable on Python 2
* fix issue `#68 <https://github.com/ilanschnell/bitarray/issues/68>`__, ``unittest.TestCase.assert_`` deprecated
* improved test suite - tests should run in about 1 second
* update documentation to use positional-only syntax in docstrings
* update readme to pass Python 3 doctest
* add utils module to examples


**1.0.1** (2019-07-19):

* fix readme to pass ``twine check``


**1.0.0** (2019-07-15):

* fix bitarrays beings created from unicode in Python 2
* use ``PyBytes_*`` in C code, treating the Py3k function names as default,
  which also removes all redefinitions of ``PyString_*``
* handle negative arguments of .index() method consistently with how
  they are treated for lists
* add a few more comments to the C code
* move imports outside tests: pickle, io, etc.
* drop Python 2.5 support


**0.9.3** (2019-05-20):

* refactor resize() - only shrink allocated memory if new size falls
  lower than half the allocated size
* improve error message when trying to initialize from float or complex


**0.9.2** (2019-04-29):

* fix to compile on Windows with VS 2015, issue `#72 <https://github.com/ilanschnell/bitarray/issues/72>`__


**0.9.1** (2019-04-28):

* fix types to actually be types, `#29 <https://github.com/ilanschnell/bitarray/issues/29>`__
* check for ambiguous prefix codes when building binary tree for decoding
* remove Python level methods: encode, decode, iterdecode (in favor of
  having these implemented on the C-level along with check_codedict)
* fix self tests for Python 2.5 and 2.6
* move all Huffman code related example code into examples/huffman
* add code to generate graphviz .dot file of Huffman tree to examples


**0.9.0** (2019-04-22):

* more efficient decode and iterdecode by using C-level binary tree
  instead of a python one, `#54 <https://github.com/ilanschnell/bitarray/issues/54>`__
* added buffer protocol support for Python 3, `#55 <https://github.com/ilanschnell/bitarray/issues/55>`__
* fixed invalid pointer exceptions in pypy, `#47 <https://github.com/ilanschnell/bitarray/issues/47>`__
* made all examples Py3k compatible
* add gene sequence example
* add official Python 3.7 support
* drop Python 2.4, 3.1 and 3.2 support


**0.8.3** (2018-07-06):

* add exception to setup.py when README.rst cannot be opened


**0.8.2** (2018-05-30):

* add official Python 3.6 support (although it was already working)
* fix description of ``fill()``, `#52 <https://github.com/ilanschnell/bitarray/issues/52>`__
* handle extending self correctly, `#28 <https://github.com/ilanschnell/bitarray/issues/28>`__
* ``copy_n()``: fast copy with ``memmove()`` fixed, `#43 <https://github.com/ilanschnell/bitarray/issues/43>`__
* minor clarity/wording changes to README, `#23 <https://github.com/ilanschnell/bitarray/issues/23>`__


**0.8.1** (2013-03-30):

* fix issue `#10 <https://github.com/ilanschnell/bitarray/issues/10>`__, i.e. ``int(bitarray())`` segfault
* added tests for using a bitarray object as an argument to functions
  like int, long (on Python 2), float, list, tuple, dict


**0.8.0** (2012-04-04):

* add Python 2.4 support
* add (module level) function bitdiff for calculating the difference
  between two bitarrays


**0.7.0** (2012-02-15):

* add iterdecode method (C level), which returns an iterator but is
  otherwise like the decode method
* improve memory efficiency and speed of pickling large bitarray objects


**0.6.0** (2012-02-06):

* add buffer protocol to bitarray objects (Python 2.7 only)
* allow slice assignment to 0 or 1, e.g. ``a[::3] = 0``  (in addition to
  booleans)
* moved implementation of itersearch method to C level (Lluis Pamies)
* search, itersearch now only except bitarray objects,
  whereas ``__contains__`` excepts either booleans or bitarrays
* use a priority queue for Huffman tree example (thanks to Ushma Bhatt)
* improve documentation


**0.5.2** (2012-02-02):

* fixed MSVC compile error on Python 3 (thanks to Chris Gohlke)
* add missing start and stop optional parameters to index() method
* add examples/compress.py


**0.5.1** (2012-01-31):

* update documentation to use tobytes and frombytes, rather than tostring
  and fromstring (which are now deprecated)
* simplified how tests are run


**0.5.0** (2012-01-23):

* added itersearch method
* added Bloom filter example
* minor fixes in docstrings, added more tests


**0.4.0** (2011-12-29):

* porting to Python 3.x (Roland Puntaier)
* introduced ``.tobytes()`` and ``.frombytes()`` (``.tostring()``
  and ``.fromstring()`` are now deprecated)
* updated development status
* added sieve prime number example
* moved project to github: https://github.com/ilanschnell/bitarray


**0.3.5** (2009-04-06):

* fixed reference counts bugs
* added possibility to slice assign to ``True`` or ``False``,
  e.g. ``a[::3] = True`` will set every third element to ``True``


**0.3.4** (2009-01-15):

* Made C code less ambiguous, such that the package compiles on
  Visual Studio, with all tests passing.


**0.3.3** (2008-12-14):

* Made changes to the C code to allow compilation with more compilers.
  Compiles on Visual Studio, although there are still a few tests failing.


**0.3.2** (2008-10-19):

* Added sequential search method.
* The special method ``__contains__`` now also takes advantage of the
  sequential search.


**0.3.1** (2008-10-12):

* Simplified state information for pickling.  Argument for count is now
  optional, defaults to True.  Fixed typos.


**0.3.0** (2008-09-30):

* Fixed a severe bug for 64-bit machines.  Implemented all methods in C,
  improved tests.
* Removed deprecated methods ``.from01()`` and ``.fromlist()``.


**0.2.5** (2008-09-23):

* Added section in README about prefix codes.  Implemented _multiply method
  for faster ``__mul__`` and ``__imul__``.  Fixed some typos.


**0.2.4** (2008-09-22):

* Implemented encode and decode method (in C) for variable-length prefix
  codes.
* Added more examples, wrote README for the examples.
* Added more tests, fixed some typos.


**0.2.3** (2008-09-16):

* Fixed a memory leak, implemented a number of methods in C.
  These include __getitem__, __setitem__, __delitem__, pop, remove,
  insert.  The methods implemented on the Python level is very limit now.
* Implemented bitwise operations.


**0.2.2** (2008-09-09):

* Rewrote parts of the README
* Implemented memory efficient algorithm for the reverse method
* Fixed typos, added a few tests, more C refactoring.


**0.2.1** (2008-09-07):

* Improved tests, in particular added checking for memory leaks.
* Refactored many things on the C level.
* Implemented a few more methods.


**0.2.0** (2008-09-02):

* Added bit-endianness property to the bitarray object
* Added the examples to the release package.


**0.1.0** (2008-08-17):

* First official release; put project to
  http://pypi.python.org/pypi/bitarray/


May 2008:

Wrote the initial code, and put it on my personal web-site:
http://ilan.schnell-web.net/prog/