python class bf for bitfields manipulation is a rev 2 for the Recipe 113799 rev 1 include the bug fix detected for Patric Edsall and other tools
Python, 91 lines
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# bitfield manipulation
#
class bf(object):
def __init__(self,value=0):
"Init bitfield with a value int in bin, hex, oct or dec"
self._d = value
def __getitem__(self, index):
"return bit value for that index (n-0)"
return (self._d >> index) & 1
def __setitem__(self,index,value):
"set bit value for that index (n-0)"
value = (value&1)<<index
mask = (1)<<index
self._d = (self._d & ~mask) | value
def __getslice__(self, start, end):
"return bits slice from start to end (n-0)"
mask = 2**(end - start + 1) -1
return ((self._d >> start) & mask)
def __setslice__(self, start, end, value):
"set bits slice from start to end index (n-0) with the given value"
mask = 2**(end - start + 1) -1
value = (value & mask) << start
mask = mask << start
self._d = (self._d & ~mask) | value
return (self._d >> start) & mask
def __int__(self):
"add de int() function for bf"
return self._d
def int(self):
"add the bf.int() function return int"
return self._d
def bin(self):
"add the bf.bin() function return str"
return '{0:0b}'.format(self._d)
def hex(self):
"add the bf.hex() function return str"
return '{0:0x}'.format(self._d)
def __repr__(self):
"add the basic return function, return bin str"
return '{0:0b}'.format(self._d)
def __len__(self):
"add the len() function return int with the bit number count"
return len('{0:0b}'.format(self._d))
def unpack(self,pack):
"return the unpack bit fields in dec [ n1, n2, n3...] with length given in pack [ l1, l2, l3...]"
r=[]; ss=0;pack.reverse()
for i in pack:
r.append(self.__getslice__(ss,ss+i-1))
ss +=i
r.reverse()
return r
def pack(self,pack):
"return bf with the given values in dec [n1, n2, n3...] packed"
r=bf(); ss=0;pack.reverse()
for i in pack:
l1=len(bin(i))-2
r.__setslice__(ss,ss+l1,i)
ss +=l1
return r
if __name__ == "__main__":
k = bf(0x0f)
k[10:20] =0xfffffffffff
k[3:7]=0b10101
print k[3]
print k[5]
print k
print len(k)
print k.unpack([5, 3,1,7]),(k.unpack([5, 3,1,7]))[1]
b1,b2,b3,b4 = k.unpack([5, 3,1,7])
print b1,b2,b3,b4
print bf().pack([0b1101,0b1001])
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