CQPacker.py

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#!/usr/bin/env python
"""

::

    mask6 = int(''.join(statusL[186:192]), 2)
    ValueError: invalid literal for int() with base 2: '0000b1'

"""

class CQPacker(object):
    def __init__(self):
        pass

    def pack(self, statusL):
        """ 
            pack the 192 status into 7 int 
            statusL: list of status str for 192 PMTs order by channelid, e.g. ['1','1','0',...,'1'].
                     when CQ service unpack the bits, should follow channelid order.
        """
        assert len(statusL)==192, 'packing: length of status str != 192'
        mask0 = int(''.join(statusL[0:31]), 2)
        mask1 = int(''.join(statusL[31:62]), 2)
        mask2 = int(''.join(statusL[62:93]), 2)
        mask3 = int(''.join(statusL[93:124]), 2)
        mask4 = int(''.join(statusL[124:155]), 2)
        mask5 = int(''.join(statusL[155:186]), 2)
        mask6 = int(''.join(statusL[186:192]), 2)
        return [mask0, mask1, mask2, mask3, mask4, mask5, mask6]

    def unpack(self, masks):
        """
            upack status from masks, return a list of status str, i.e. ['1','1',...,'1']
            masks: list of mask, i.e. [mask0, mask1, ..., mask6]
        """
        statusL = []
        for i in range(7):
            unmask = list(bin(masks[i])[2:]) # bin(mask) in form of '0b11'
            nbits = len(unmask)
            nbitsExp=6 if i==6 else 31
            unmask = ['0']*(nbitsExp-nbits) + unmask # in case the first several bit is 0
            statusL += unmask
        assert len(statusL)==192, 'unpacking: length of status str != 192'
        return statusL


        
if __name__ == '__main__':
    packer = CQPacker()
    import random
    nb = 192
    checks = [random.getrandbits(nb) for _ in range(1000)]
    checks += [0, (1<<nb) - 1 ]
    #checks += [-1]   # causes invalid literal for int() with base 2: '0000b1'

    for i, st in enumerate(checks): 
        b = bin(st)[2:]
        ist = '0' * (nb - len(b)) + b  
        print "%-6s %-4s %s " % ( i, len(ist), ist )
        msk = packer.pack(ist)
        ost = ''.join(packer.unpack( msk )) 
        assert ist == ost , (i, ist, ost)