def int2bytes(number, fill_size=None, chunk_size=None, overflow=False):
if number < 0:
raise ValueError('Number must be an unsigned integer: %d' % number)
if fill_size and chunk_size:
raise ValueError('You can either fill or pad chunks, but not both')
number & 1
raw_bytes = b('')
num = number
word_bits, _, max_uint, pack_type = get_word_alignment(num)
pack_format = '>%s' % pack_type
while num > 0:
raw_bytes = pack(pack_format, num & max_uint) + raw_bytes
num >>= word_bits
zero_leading = bytes_leading(raw_bytes)
if number == 0:
raw_bytes = ZERO_BYTE
raw_bytes = raw_bytes[zero_leading:]
length = len(raw_bytes)
if fill_size and fill_size > 0:
if not overflow and length > fill_size:
raise OverflowError(
'Need %d bytes for number, but fill size is %d' %
(length, fill_size))
raw_bytes = raw_bytes.rjust(fill_size, ZERO_BYTE)
elif chunk_size and chunk_size > 0:
remainder = length % chunk_size
if remainder:
padding_size = chunk_size - remainder
raw_bytes = raw_bytes.rjust(length + padding_size, ZERO_BYTE)
return raw_bytes
def int2bytes(number, fill_size=None, chunk_size=None, overflow=False):
'''
Convert an unsigned integer to bytes (base-256 representation)::
Does not preserve leading zeros if you don't specify a chunk size or
fill size.
.. NOTE:
You must not specify both fill_size and chunk_size. Only one
of them is allowed.
:param number:
Integer value
:param fill_size:
If the optional fill size is given the length of the resulting
byte string is expected to be the fill size and will be padded
with prefix zero bytes to satisfy that length.
:param chunk_size:
If optional chunk size is given and greater than zero, pad the front of
the byte string with binary zeros so that the length is a multiple of
``chunk_size``.
:param overflow:
``False`` (default). If this is ``True``, no ``OverflowError``
will be raised when the fill_size is shorter than the length
of the generated byte sequence. Instead the byte sequence will
be returned as is.
:returns:
Raw bytes (base-256 representation).
:raises:
``OverflowError`` when fill_size is given and the number takes up more
bytes than fit into the block. This requires the ``overflow``
argument to this function to be set to ``False`` otherwise, no
error will be raised.
'''
if number < 0:
raise ValueError("Number must be an unsigned integer: %d" % number)
if fill_size and chunk_size:
raise ValueError("You can either fill or pad chunks, but not both")
# Ensure these are integers.
number & 1
raw_bytes = b('')
# Pack the integer one machine word at a time into bytes.
num = number
word_bits, _, max_uint, pack_type = get_word_alignment(num)
pack_format = ">%s" % pack_type
while num > 0:
raw_bytes = pack(pack_format, num & max_uint) + raw_bytes
num >>= word_bits
# Obtain the index of the first non-zero byte.
zero_leading = bytes_leading(raw_bytes)
if number == 0:
raw_bytes = ZERO_BYTE
# De-padding.
raw_bytes = raw_bytes[zero_leading:]
length = len(raw_bytes)
if fill_size and fill_size > 0:
if not overflow and length > fill_size:
raise OverflowError(
"Need %d bytes for number, but fill size is %d" %
(length, fill_size))
raw_bytes = raw_bytes.rjust(fill_size, ZERO_BYTE)
elif chunk_size and chunk_size > 0:
remainder = length % chunk_size
if remainder:
padding_size = chunk_size - remainder
raw_bytes = raw_bytes.rjust(length + padding_size, ZERO_BYTE)
return raw_bytes
def int2bytes(number, fill_size=None, chunk_size=None, overflow=False):
"""
Convert an unsigned integer to bytes (base-256 representation)::
Does not preserve leading zeros if you don't specify a chunk size or
fill size.
.. NOTE:
You must not specify both fill_size and chunk_size. Only one
of them is allowed.
:param number:
Integer value
:param fill_size:
If the optional fill size is given the length of the resulting
byte string is expected to be the fill size and will be padded
with prefix zero bytes to satisfy that length.
:param chunk_size:
If optional chunk size is given and greater than zero, pad the front of
the byte string with binary zeros so that the length is a multiple of
``chunk_size``.
:param overflow:
``False`` (default). If this is ``True``, no ``OverflowError``
will be raised when the fill_size is shorter than the length
of the generated byte sequence. Instead the byte sequence will
be returned as is.
:returns:
Raw bytes (base-256 representation).
:raises:
``OverflowError`` when fill_size is given and the number takes up more
bytes than fit into the block. This requires the ``overflow``
argument to this function to be set to ``False`` otherwise, no
error will be raised.
"""
if number < 0:
raise ValueError("Number must be an unsigned integer: %d" % number)
if fill_size and chunk_size:
raise ValueError("You can either fill or pad chunks, but not both")
# Ensure these are integers.
number & 1
raw_bytes = b('')
# Pack the integer one machine word at a time into bytes.
num = number
word_bits, _, max_uint, pack_type = get_word_alignment(num)
pack_format = ">%s" % pack_type
while num > 0:
raw_bytes = pack(pack_format, num & max_uint) + raw_bytes
num >>= word_bits
# Obtain the index of the first non-zero byte.
zero_leading = bytes_leading(raw_bytes)
if number == 0:
raw_bytes = ZERO_BYTE
# De-padding.
raw_bytes = raw_bytes[zero_leading:]
length = len(raw_bytes)
if fill_size and fill_size > 0:
if not overflow and length > fill_size:
raise OverflowError(
"Need %d bytes for number, but fill size is %d" %
(length, fill_size)
)
raw_bytes = raw_bytes.rjust(fill_size, ZERO_BYTE)
elif chunk_size and chunk_size > 0:
remainder = length % chunk_size
if remainder:
padding_size = chunk_size - remainder
raw_bytes = raw_bytes.rjust(length + padding_size, ZERO_BYTE)
return raw_bytes
