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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
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91``` ```# # 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)<> 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]) ```
 Created by juan on Sun, 17 Aug 2014 (MIT)

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