btl.utils

This module contains lower-level functions for converting values to binary format and vice versa.

Note

The bitarray.bitarray instances passed to and returned from the functions in this module, are expected to be big-endian.

btl.utils.bita_to_bool(b)

Return a boolean value represented by the specified bitarray instance.

Example:

>>> bita_to_bool(bitarray('0'))
False

btl.utils.bita_to_bytes(b)

Return a bytestring that is represented by the specified bitarray instance.

Note

This function does exactly the same thing as calling the tobytes() method.

Example:

>>> ba = bitarray('011001100110111101101111')
>>> bita_to_bytes(ba)
'foo'

btl.utils.bita_to_hex(b)

Return a hex number represented by the specified bitarray instance.

Example:

>>> bita_to_hex(bitarray('1111000100101010'))
'f12a'

btl.utils.bita_to_int(b)

Return an integer that corresponds to the specified bitarray. The bitarray must represent a number that falls in the C long long range. Any significant bits beyond the 64 bits required to build a long long will be stripped away, and additional bits will be padded as needed to match the 64 bit length.

Example:

>>> bita_to_int(bitarray('1100'))
12

btl.utils.bita_to_str(b)

Return a string represented by the specified bitarray instance. The output is a unicode string. It is assumed that the input represents a UTF-8-encoded bytestring.

Example:

>>> bita = bitarray('011001100110111101101111')
>>> bita_to_str(bita)
u'foo'

btl.utils.bool_to_bita(b)

Return a bitarray instance representing the boolean value.

Example:

>>> bool_to_bita(True)
bitarray('1')

btl.utils.bytes_to_bita(s)

Return a bitarray instance representing the bytestring. There is no limit to the length of the input.

Note

This function does exactly the same thing as packing bits into a bitarray object using the frombytes() method.

Example:

>>> bytes_to_bita('foo')
bitarray('011001100110111101101111')

btl.utils.hex_digit_to_bita(h)

Return a 4-bit bitearray instance that represents a single hex digit.

Example:

>>> hex_digit_to_bita('a')
bitarray('1010')

btl.utils.hex_to_bita(h)

Return a bitarray instance representing the hex number in the input string. There is no limit to the length of the input.

Example:

>>> hex_to_bita('f12a')
bitarray('1111000100101010')

btl.utils.int_to_bita(n)

Return a bitarray instance representing the specified number. The number must be an usigned integer. The number must be in C long long range.

The return value will contain 64 bits (size of long long).

Example:

>>> int_to_bita(12)[-8:]
bitarray('00001100')

btl.utils.str_to_bita(s)

Return a bitarray instance representing the specified string. The input can be a unicode string or a bytestring. Unicode strings will be encoded as UTF-8.

Example:

>>> str_to_bita(u'foo')
bitarray('011001100110111101101111')