chainlib-eth

Ethereum implementation of the chainlib interface
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log.py (726B)

      1 # external imports
      2 import sha3
      3 
      4 
      5 class LogBloom:
      6     """Helper for Ethereum receipt log bloom filters.
      7     """
      8     def __init__(self):
      9         self.content = bytearray(256)
     10 
     11 
     12     def add(self, element):
     13         """Add topic element to filter.
     14 
     15         :param element: Topic element
     16         :type element: bytes
     17         """
     18         if not isinstance(element, bytes):
     19             raise ValueError('element must be bytes')
     20         h = sha3.keccak_256()
     21         h.update(element)
     22         z = h.digest()
     23 
     24         for j in range(3):
     25             c = j * 2
     26             v = int.from_bytes(z[c:c+2], byteorder='big')
     27             v &= 0x07ff
     28             m = 255 - int(v / 8)
     29             n = v % 8
     30             self.content[m] |= (1 << n)