Metadata-Version: 1.1
Name: bitarray
Version: 1.5.0
Summary: efficient arrays of booleans -- C extension
Home-page: https://github.com/ilanschnell/bitarray
Author: Ilan Schnell
Author-email: ilanschnell@gmail.com
License: PSF
Description: bitarray: efficient arrays of booleans
        ======================================
        
        This module provides an object type which efficiently represents an array
        of booleans.  Bitarrays are sequence types and behave very much like usual
        lists.  Eight bits are represented by one byte in a contiguous block of
        memory.  The user can select between two representations: little-endian
        and big-endian.  All of the functionality is implemented in C.
        Methods for accessing the machine representation are provided.
        This can be useful when bit level access to binary files is required,
        such as portable bitmap image files (.pbm).  Also, when dealing with
        compressed data which uses variable bit length encoding, you may find
        this module useful.
        
        
        Key features
        ------------
        
         * All functionality implemented in C.
         * Bitarray objects behave very much like a list object, in particular
           slicing (including slice assignment and deletion) is supported.
         * The bit endianness can be specified for each bitarray object, see below.
         * Packing and unpacking to other binary data formats, e.g. numpy.ndarray
           is possible.
         * Fast methods for encoding and decoding variable bit length prefix codes
         * Bitwise operations: `&`, `|`, `^`, `&=`, `|=`, `^=`, `~`
         * Sequential search
         * Pickling and unpickling of bitarray objects.
         * Bitarray objects support the buffer protocol (Python 2.7 and above)
         * On 32-bit systems, a bitarray object can contain up to 2 Gbits.
        
        
        Installation
        ------------
        
        Bitarray can be installed from source:
        
            $ tar xzf bitarray-1.5.0.tar.gz
            $ cd bitarray-1.5.0
            $ python setup.py install
        
        On Unix systems, the latter command may have to be executed with root
        privileges.  You can also pip install bitarray.
        Once you have installed the package, you may want to test it:
        
            $ python -c 'import bitarray; bitarray.test()'
            bitarray is installed in: /usr/local/lib/python2.7/site-packages/bitarray
            bitarray version: 1.5.0
            3.7.4 (r271:86832, Dec 29 2018) [GCC 4.2.1 (SUSE Linux)]
            .........................................................................
            .........................................................................
            ..............................
            ----------------------------------------------------------------------
            Ran 230 tests in 0.889s
        
            OK
        
        You can always import the function test,
        and `test().wasSuccessful()` will return `True` when the test went well.
        
        
        Using the module
        ----------------
        
        As mentioned above, bitarray objects behave very much like lists, so
        there is not too much to learn.  The biggest difference from list
        objects (except that bitarray are obviously homogeneous) is the ability
        to access the machine representation of the object.
        When doing so, the bit endianness is of importance; this issue is
        explained in detail in the section below.  Here, we demonstrate the
        basic usage of bitarray objects:
        
            >>> from bitarray import bitarray
            >>> a = bitarray()            # create empty bitarray
            >>> a.append(True)
            >>> a.extend([False, True, True])
            >>> a
            bitarray('1011')
        
        Bitarray objects can be instantiated in different ways:
        
            >>> a = bitarray(2**20)       # bitarray of length 1048576 (uninitialized)
            >>> bitarray('1001011')       # from a string
            bitarray('1001011')
            >>> lst = [True, False, False, True, False, True, True]
            >>> bitarray(lst)             # from list, tuple, iterable
            bitarray('1001011')
        
        Bits can be assigned from any Python object, if the value can be interpreted
        as a truth value.  You can think of this as Python's built-in function bool()
        being applied, whenever casting an object:
        
            >>> a = bitarray([42, '', True, {}, 'foo', None])
            >>> a
            bitarray('101010')
            >>> a.append(a)      # note that bool(a) is True
            >>> a.count(42)      # counts occurrences of True (not 42)
            4
            >>> a.remove('')     # removes first occurrence of False
            >>> a
            bitarray('110101')
        
        Like lists, bitarray objects support slice assignment and deletion:
        
            >>> a = bitarray(50)
            >>> a.setall(False)
            >>> a[11:37:3] = 9 * bitarray([True])
            >>> a
            bitarray('00000000000100100100100100100100100100000000000000')
            >>> del a[12::3]
            >>> a
            bitarray('0000000000010101010101010101000000000')
            >>> a[-6:] = bitarray('10011')
            >>> a
            bitarray('000000000001010101010101010100010011')
            >>> a += bitarray('000111')
            >>> a[9:]
            bitarray('001010101010101010100010011000111')
        
        In addition, slices can be assigned to booleans, which is easier (and
        faster) than assigning to a bitarray in which all values are the same:
        
            >>> a = 20 * bitarray('0')
            >>> a[1:15:3] = True
            >>> a
            bitarray('01001001001001000000')
        
        This is easier and faster than:
        
            >>> a = 20 * bitarray('0')
            >>> a[1:15:3] = 5 * bitarray('1')
            >>> a
            bitarray('01001001001001000000')
        
        Note that in the latter we have to create a temporary bitarray whose length
        must be known or calculated.
        
        
        Bit endianness
        --------------
        
        Since a bitarray allows addressing of individual bits, where the machine
        represents 8 bits in one byte, there are two obvious choices for this
        mapping: little- and big-endian.
        When creating a new bitarray object, the endianness can always be
        specified explicitly:
        
            >>> a = bitarray(endian='little')
            >>> a.frombytes(b'A')
            >>> a
            bitarray('10000010')
            >>> b = bitarray('11000010', endian='little')
            >>> b.tobytes()
            b'C'
        
        Here, the low-bit comes first because little-endian means that increasing
        numeric significance corresponds to an increasing address (index).
        So `a[0]` is the lowest and least significant bit, and `a[7]` is the
        highest and most significant bit.
        
            >>> a = bitarray(endian='big')
            >>> a.frombytes(b'A')
            >>> a
            bitarray('01000001')
            >>> a[6] = 1
            >>> a.tobytes()
            b'C'
        
        Here, the high-bit comes first because big-endian
        means "most-significant first".
        So `a[0]` is now the lowest and most significant bit, and `a[7]` is the
        highest and least significant bit.
        
        The bit endianness is a property attached to each bitarray object.
        When comparing bitarray objects, the endianness (and hence the machine
        representation) is irrelevant; what matters is the mapping from indices
        to bits:
        
            >>> bitarray('11001', endian='big') == bitarray('11001', endian='little')
            True
        
        Bitwise operations (`&`, `|`, `^`, `&=`, `|=`, `^=`, `~`) are implemented
        efficiently using the corresponding byte operations in C, i.e. the operators
        act on the machine representation of the bitarray objects.
        Therefore, one has to be cautious when applying the operation to bitarrays
        with different endianness.
        
        When converting to and from machine representation, using
        the `tobytes`, `frombytes`, `tofile` and `fromfile` methods,
        the endianness matters:
        
            >>> a = bitarray(endian='little')
            >>> a.frombytes(b'\x01')
            >>> a
            bitarray('10000000')
            >>> b = bitarray(endian='big')
            >>> b.frombytes(b'\x80')
            >>> b
            bitarray('10000000')
            >>> a == b
            True
            >>> a.tobytes() == b.tobytes()
            False
        
        The endianness can not be changed once an object is created.
        However, since creating a bitarray from another bitarray just copies the
        memory representing the data, you can create a new bitarray with different
        endianness:
        
            >>> a = bitarray('11100000', endian='little')
            >>> a
            bitarray('11100000')
            >>> b = bitarray(a, endian='big')
            >>> b
            bitarray('00000111')
            >>> a == b
            False
            >>> a.tobytes() == b.tobytes()
            True
        
        The default bit endianness is currently big-endian, however this may change
        in the future, and when dealing with the machine representation of bitarray
        objects, it is recommended to always explicitly specify the endianness.
        
        Unless explicitly converting to machine representation, using
        the `tobytes`, `frombytes`, `tofile` and `fromfile` methods,
        the bit endianness will have no effect on any computation, and one
        can safely ignore setting the endianness, and other details of this section.
        
        
        Buffer protocol
        ---------------
        
        Python 2.7 provides memoryview objects, which allow Python code to access
        the internal data of an object that supports the buffer protocol without
        copying.  Bitarray objects support this protocol, with the memory being
        interpreted as simple bytes.
        
            >>> a = bitarray('01000001' '01000010' '01000011', endian='big')
            >>> v = memoryview(a)
            >>> len(v)
            3
            >>> v[-1]
            67
            >>> v[:2].tobytes()
            b'AB'
            >>> v.readonly  # changing a bitarray's memory is also possible
            False
            >>> v[1] = 111
            >>> a
            bitarray('010000010110111101000011')
        
        
        Variable bit length prefix codes
        --------------------------------
        
        The method `encode` takes a dictionary mapping symbols to bitarrays
        and an iterable, and extends the bitarray object with the encoded symbols
        found while iterating.  For example:
        
            >>> d = {'H':bitarray('111'), 'e':bitarray('0'),
            ...      'l':bitarray('110'), 'o':bitarray('10')}
            ...
            >>> a = bitarray()
            >>> a.encode(d, 'Hello')
            >>> a
            bitarray('111011011010')
        
        Note that the string `'Hello'` is an iterable, but the symbols are not
        limited to characters, in fact any immutable Python object can be a symbol.
        Taking the same dictionary, we can apply the `decode` method which will
        return a list of the symbols:
        
            >>> a.decode(d)
            ['H', 'e', 'l', 'l', 'o']
            >>> ''.join(a.decode(d))
            'Hello'
        
        Since symbols are not limited to being characters, it is necessary to return
        them as elements of a list, rather than simply returning the joined string.
        
        
        Reference
        =========
        
        The bitarray object:
        --------------------
        
        `bitarray(initializer=0, /, endian='big')` -> bitarray
        
        Return a new bitarray object whose items are bits initialized from
        the optional initial object, and endianness.
        The initializer may be of the following types:
        
        `int`: Create a bitarray of given integer length.  The initial values are
        arbitrary.  If you want all values to be set, use the .setall() method.
        
        `str`: Create bitarray from a string of `0` and `1`.
        
        `list`, `tuple`, `iterable`: Create bitarray from a sequence, each
        element in the sequence is converted to a bit using its truth value.
        
        `bitarray`: Create bitarray from another bitarray.  This is done by
        copying the memory holding the bitarray data, and is hence very fast.
        
        The optional keyword arguments `endian` specifies the bit endianness of the
        created bitarray object.
        Allowed values are the strings `big` and `little` (default is `big`).
        
        Note that setting the bit endianness only has an effect when accessing the
        machine representation of the bitarray, i.e. when using the methods: tofile,
        fromfile, tobytes, frombytes.
        
        
        **A bitarray object supports the following methods:**
        
        `all()` -> bool
        
        Returns True when all bits in the array are True.
        
        
        `any()` -> bool
        
        Returns True when any bit in the array is True.
        
        
        `append(item, /)`
        
        Append the truth value `bool(item)` to the end of the bitarray.
        
        
        `buffer_info()` -> tuple
        
        Return a tuple (address, size, endianness, unused, allocated) giving the
        memory address of the bitarray's data, the size (in bytes) used to hold the
        bitarray's contents, the bit endianness as a string, the number of unused
        bits in the last bytes, and the size (in bytes) of the allocated memory.
        
        
        `bytereverse()`
        
        For all bytes representing the bitarray, reverse the bit order (in-place).
        Note: This method changes the actual machine values representing the
        bitarray; it does not change the endianness of the bitarray object.
        
        
        `clear()`
        
        Remove all items from the bitarray.
        
        
        `copy()` -> bitarray
        
        Return a copy of the bitarray.
        
        
        `count(value=True, start=0, stop=<end of array>, /)` -> int
        
        Count the number of occurrences of bool(value) in the bitarray.
        
        
        `decode(code, /)` -> list
        
        Given a prefix code (a dict mapping symbols to bitarrays),
        decode the content of the bitarray and return it as a list of symbols.
        
        
        `encode(code, iterable, /)`
        
        Given a prefix code (a dict mapping symbols to bitarrays),
        iterate over the iterable object with symbols, and extend the bitarray
        with the corresponding bitarray for each symbol.
        
        
        `endian()` -> str
        
        Return the bit endianness of the bitarray as a string (`little` or `big`).
        
        
        `extend(iterable or string, /)`
        
        Extend bitarray by appending the truth value of each element given
        by iterable.  If a string is provided, each `0` and `1` are appended
        as bits.
        
        
        `fill()` -> int
        
        Adds zeros to the end of the bitarray, such that the length of the bitarray
        will be a multiple of 8.  Returns the number of bits added (0..7).
        
        
        `frombytes(bytes, /)`
        
        Extend bitarray with raw bytes.  That is, each append byte will add eight
        bits to the bitarray.
        
        
        `fromfile(f, n=-1, /)`
        
        Extend bitarray with up to n bytes read from the file object f.
        When n is omitted or negative, reads all data until EOF.
        When n is provided and positions but exceeds the data available,
        EOFError is raised (but the available data is still read and appended.
        
        
        `index(value, start=0, stop=<end of array>, /)` -> int
        
        Return index of the first occurrence of `bool(value)` in the bitarray.
        Raises `ValueError` if the value is not present.
        
        
        `insert(index, value, /)`
        
        Insert `bool(value)` into the bitarray before index.
        
        
        `invert()`
        
        Invert all bits in the array (in-place),
        i.e. convert each 1-bit into a 0-bit and vice versa.
        
        
        `iterdecode(code, /)` -> iterator
        
        Given a prefix code (a dict mapping symbols to bitarrays),
        decode the content of the bitarray and return an iterator over
        the symbols.
        
        
        `itersearch(bitarray, /)` -> iterator
        
        Searches for the given a bitarray in self, and return an iterator over
        the start positions where bitarray matches self.
        
        
        `length()` -> int
        
        Return the length - a.length() is the same as len(a).
        
        
        `pack(bytes, /)`
        
        Extend the bitarray from bytes, where each byte corresponds to a single
        bit.  The byte `b'\x00'` maps to bit 0 and all other characters map to
        bit 1.
        This method, as well as the unpack method, are meant for efficient
        transfer of data between bitarray objects to other python objects
        (for example NumPy's ndarray object) which have a different memory view.
        
        
        `pop(index=-1, /)` -> item
        
        Return the i-th (default last) element and delete it from the bitarray.
        Raises `IndexError` if bitarray is empty or index is out of range.
        
        
        `remove(value, /)`
        
        Remove the first occurrence of `bool(value)` in the bitarray.
        Raises `ValueError` if item is not present.
        
        
        `reverse()`
        
        Reverse the order of bits in the array (in-place).
        
        
        `search(bitarray, limit=<none>, /)` -> list
        
        Searches for the given bitarray in self, and return the list of start
        positions.
        The optional argument limits the number of search results to the integer
        specified.  By default, all search results are returned.
        
        
        `setall(value, /)`
        
        Set all bits in the bitarray to `bool(value)`.
        
        
        `sort(reverse=False)`
        
        Sort the bits in the array (in-place).
        
        
        `to01()` -> str
        
        Return a string containing '0's and '1's, representing the bits in the
        bitarray object.
        
        
        `tobytes()` -> bytes
        
        Return the byte representation of the bitarray.
        When the length of the bitarray is not a multiple of 8, the few remaining
        bits (1..7) are considered to be 0.
        
        
        `tofile(f, /)`
        
        Write the byte representation of the bitarray to the file object f.
        When the length of the bitarray is not a multiple of 8,
        the remaining bits (1..7) are set to 0.
        
        
        `tolist()` -> list
        
        Return a list with the items (False or True) in the bitarray.
        Note that the list object being created will require 32 or 64 times more
        memory (depending on the machine architecture) than the bitarray object,
        which may cause a memory error if the bitarray is very large.
        
        
        `unpack(zero=b'\x00', one=b'\xff')` -> bytes
        
        Return bytes containing one character for each bit in the bitarray,
        using the specified mapping.
        
        
        The frozenbitarray object:
        --------------------------
        
        This object is very similar to the bitarray object.  The difference is that
        this a frozenbitarray is immutable, and hashable:
        
            >>> from bitarray import frozenbitarray
            >>> a = frozenbitarray('1100011')
            >>> a[3] = 1
            Traceback (most recent call last):
              File "<stdin>", line 1, in <module>
              File "bitarray/__init__.py", line 40, in __delitem__
                raise TypeError("'frozenbitarray' is immutable")
            TypeError: 'frozenbitarray' is immutable
            >>> {a: 'some value'}
            {frozenbitarray('1100011'): 'some value'}
        
        `frozenbitarray(initializer=0, /, endian='big')` -> frozenbitarray
        
        Return a frozenbitarray object, which is initialized the same way a bitarray
        object is initialized.  A frozenbitarray is immutable and hashable.
        Its contents cannot be altered after it is created; however, it can be used
        as a dictionary key.
        
        
        Functions defined in the `bitarray` package:
        --------------------------------------------
        
        `test(verbosity=1, repeat=1)` -> TextTestResult
        
        Run self-test, and return unittest.runner.TextTestResult object.
        
        
        `bits2bytes(n, /)` -> int
        
        Return the number of bytes necessary to store n bits.
        
        
        `get_default_endian()` -> string
        
        Return the default endianness for new bitarray objects being created.
        Under normal circumstances, the return value is `big`.
        
        
        Functions defined in `bitarray.util` module:
        --------------------------------------------
        
        `zeros(length, /, endian=None)` -> bitarray
        
        Create a bitarray of length, with all values 0, and optional
        endianness, which may be 'big', 'lillte'.
        
        
        `make_endian(bitarray, endian, /)` -> bitarray
        
        When the endianness of the given bitarray is different from `endian`,
        return a new bitarray, with endianness `endian` and the same elements
        as the original bitarray, i.e. even though the binary representation of the
        new bitarray will be different, the returned bitarray will equal the original
        one.
        Otherwise (endianness is already `endian`) the original bitarray is returned
        unchanged.
        
        
        `rindex(bitarray, value=True, /)` -> int
        
        Return the rightmost index of `bool(value)` in bitarray.
        Raises `ValueError` if the value is not present.
        
        
        `strip(bitarray, mode='right', /)` -> bitarray
        
        Strip zeros from left, right or both ends.
        Allowed values for mode are the strings: `left`, `right`, `both`
        
        
        `count_n(a, n, /)` -> int
        
        Find the smallest index `i` for which `a[:i].count() == n`.
        Raises `ValueError`, when n exceeds total count (`a.count()`).
        
        
        `count_and(a, b, /)` -> int
        
        Returns `(a & b).count()`, but is more memory efficient,
        as no intermediate bitarray object gets created.
        
        
        `count_or(a, b, /)` -> int
        
        Returns `(a | b).count()`, but is more memory efficient,
        as no intermediate bitarray object gets created.
        
        
        `count_xor(a, b, /)` -> int
        
        Returns `(a ^ b).count()`, but is more memory efficient,
        as no intermediate bitarray object gets created.
        
        
        `subset(a, b, /)` -> bool
        
        Return True if bitarray `a` is a subset of bitarray `b` (False otherwise).
        `subset(a, b)` is equivalent to `(a & b).count() == a.count()` but is more
        efficient since we can stop as soon as one mismatch is found, and no
        intermediate bitarray object gets created.
        
        
        `ba2hex(bitarray, /)` -> hexstr
        
        Return a string containing with hexadecimal representation of
        the bitarray (which has to be multiple of 4 in length).
        
        
        `hex2ba(hexstr, /, endian=None)` -> bitarray
        
        Bitarray of hexadecimal representation.
        hexstr may contain any number of hex digits (upper or lower case).
        
        
        `ba2int(bitarray, /)` -> int
        
        Convert the given bitarray into an integer.
        The bit-endianness of the bitarray is respected.
        
        
        `int2ba(int, /, length=None, endian=None)` -> bitarray
        
        Convert the given integer into a bitarray (with given endianness,
        and no leading (big-endian) / trailing (little-endian) zeros).
        If length is provided, the result will be of this length, and an
        `OverflowError` will be raised, if the integer cannot be represented
        within length bits.
        
        
        `huffman_code(dict, /, endian=None)` -> dict
        
        Given a frequency map, a dictionary mapping symbols to thier frequency,
        calculate the Huffman code, i.e. a dict mapping those symbols to
        bitarrays (with given endianness).  Note that the symbols may be any
        hashable object (including `None`).
        
        
        Change log
        ----------
        
        *1.5.0* (2020-08-05):
        
          * Use `Py_ssize_t` for bitarray index.  This means that on 32bit
            systems, the maximun 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 tring 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 (`bitarrays(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 memoery 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 overallocation 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
        
        
        Please find the complete change log
        <a href="https://github.com/ilanschnell/bitarray/blob/master/CHANGE_LOG">here</a>.
        
Platform: UNKNOWN
Classifier: License :: OSI Approved :: Python Software Foundation License
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: C
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.6
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Topic :: Utilities
