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# -*- coding: utf-8 -*-
"""
Some basic bit mainpulation utilities
"""
from __future__ import print_function
FILTER = bytearray([ (i < 32 or i > 127) and 46 or i for i in range(256) ])
def hexdump(src, length=16, prefix=''):
"""
Print hexdump of string
>>> print(hexdump(b"abcd" * 4))
0000 61 62 63 64 61 62 63 64 61 62 63 64 61 62 63 64 abcdabcd abcdabcd
>>> print(hexdump(bytearray(range(48))))
0000 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f ........ ........
0010 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ........ ........
0020 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&' ()*+,-./
"""
n = 0
left = length // 2
right = length - left
result= []
src = bytearray(src)
while src:
s,src = src[:length],src[length:]
l,r = s[:left],s[left:]
hexa = "%-*s" % (left*3,' '.join(["%02x"%x for x in l]))
hexb = "%-*s" % (right*3,' '.join(["%02x"%x for x in r]))
lf = l.translate(FILTER)
rf = r.translate(FILTER)
result.append("%s%04x %s %s %s %s" % (prefix, n, hexa, hexb,
lf.decode(), rf.decode()))
n += length
return "\n".join(result)
def get_bits(data,offset,bits=1):
"""
Get specified bits from integer
>>> bin(get_bits(0b0011100,2))
'0b1'
>>> bin(get_bits(0b0011100,0,4))
'0b1100'
"""
mask = ((1 << bits) - 1) << offset
return (data & mask) >> offset
def set_bits(data,value,offset,bits=1):
"""
Set specified bits in integer
>>> bin(set_bits(0,0b1010,0,4))
'0b1010'
>>> bin(set_bits(0,0b1010,3,4))
'0b1010000'
"""
mask = ((1 << bits) - 1) << offset
clear = 0xffff ^ mask
data = (data & clear) | ((value << offset) & mask)
return data
def binary(n,count=16,reverse=False):
"""
Display n in binary (only difference from built-in `bin` is
that this function returns a fixed width string and can
optionally be reversed
>>> binary(6789)
'0001101010000101'
>>> binary(6789,8)
'10000101'
>>> binary(6789,reverse=True)
'1010000101011000'
"""
bits = [str((n >> y) & 1) for y in range(count-1, -1, -1)]
if reverse:
bits.reverse()
return "".join(bits)
if __name__ == '__main__':
import doctest
doctest.testmod()
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