conv.py

   1 '''
   2 Representation of a getwork request/reply
   3 '''
   4
   5 from __future__ import division
   6
   7 import struct
   8
   9 import sha256
  10
  11 def bits_to_target(bits):
  12     return (bits & 0x00ffffff) * 2 ** (8 * ((bits >> 24) - 3))
  13
  14 def target_to_attempts(target):
  15     return (2**257 + target + 1)//(2*target + 2)
  16
  17 def reverse_chunks(s, l):
  18     return ''.join(reversed([s[x:x+l] for x in xrange(0, len(s), l)]))
  19
  20 class BlockAttempt(object):
  21     def __init__(self, version, previous_block, merkle_root, timestamp, bits):
  22         self.version, self.previous_block, self.merkle_root, self.timestamp, self.bits = version, previous_block, merkle_root, timestamp, bits
  23
  24     def __repr__(self):
  25         return '<BlockAttempt %s>' % (' '.join('%s=%s' % (k, hex(v))) for k, v in self.__dict__.iteritems())
  26
  27     def __eq__(self, other):
  28         if not isinstance(other, BlockAttempt):
  29             raise ValueError('comparisons only valid with other BlockAttempts')
  30         return self.__dict__ == other.__dict__
  31
  32     def __ne__(self, other):
  33         return not (self == other)
  34
  35     def __repr__(self):
  36         return 'BlockAttempt(%s)' % (', '.join('%s=%r' % (k, v) for k, v in self.__dict__.iteritems()),)
  37
  38     def getwork(self, target_multiplier=1, _check=2):
  39         target = bits_to_target(self.bits) * target_multiplier
  40         if target >= 2**256//2**32:
  41             raise ValueError("target higher than standard maximum")
  42
  43         previous_block2 = reverse_chunks('%064x' % self.previous_block, 8).decode('hex')
  44         merkle_root2 = reverse_chunks('%064x' % self.merkle_root, 8).decode('hex')
  45         data = struct.pack('>I32s32sIII', self.version, previous_block2, merkle_root2, self.timestamp, self.bits, 0).encode('hex') + '000000800000000000000000000000000000000000000000000000000000000000000000000000000000000080020000'
  46
  47         previous_block3 = ('%064x' % self.previous_block).decode('hex')[::-1]
  48         merkle_root3 = ('%064x' % self.merkle_root).decode('hex')[::-1]
  49         data2 = struct.pack('<I32s32s', self.version, previous_block3, merkle_root3)
  50
  51         getwork = {
  52             'data': data,
  53             'hash1': '00000000000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000010000',
  54             'target': ('%064x' % (target,)).decode('hex')[::-1].encode('hex'),
  55             'midstate': reverse_chunks(sha256.process(data2[:64])[::-1], 4).encode('hex'),
  56         }
  57
  58         if _check:
  59             self2 = self.__class__.from_getwork(getwork, _check=_check - 1, _check_multiplier=target_multiplier)
  60             if self2 != self:
  61                 raise ValueError('failed check - input invalid or implementation error')
  62
  63         return getwork
  64
  65     @classmethod
  66     def from_getwork(cls, getwork, _check=2, _check_multiplier=1):
  67         attrs = decode_data(getwork['data'])
  68         attrs.pop('nonce')
  69
  70         ba = cls(**attrs)
  71
  72         if _check:
  73             getwork2 = ba.getwork(_check_multiplier, _check=_check - 1)
  74             if getwork2 != getwork:
  75                 raise ValueError('failed check - input invalid or implementation error')
  76
  77         return ba
  78
  79 def decode_data(data):
  80     version, previous_block, merkle_root, timestamp, bits, nonce = struct.unpack('>I32s32sIII', data[:160].decode('hex'))
  81     previous_block = int(reverse_chunks(previous_block.encode('hex'), 8), 16)
  82     merkle_root = int(reverse_chunks(merkle_root.encode('hex'), 8), 16)
  83     return dict(version=version, previous_block=previous_block, merkle_root=merkle_root, timestamp=timestamp, bits=bits, nonce=nonce)
  84
  85 if __name__ == '__main__':
  86     ba = BlockAttempt(
  87         1,
  88         0x000000000000148135e10208db85abb62754341a392eab1f186aab077a831cf7,
  89         0x534ea08be1ab529f484369344b6d5423ef5a0767db9b3ebb4e182bbb67962520,
  90         1305759879,
  91         440711666,
  92     )
  93     ba.getwork(1, 100)
  94     ba.getwork(10, 100)
  95     ba.from_getwork({
  96         'target': '0000000000000000000000000000000000000000000000f2b944000000000000',
  97         'midstate': '5982f893102dec03e374b472647c4f19b1b6d21ae4b2ac624f3d2f41b9719404',
  98         'hash1': '00000000000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000010000',
  99         'data': '0000000163930d52a5ffca79b29b95a659a302cd4e1654194780499000002274000000002e133d9e51f45bc0886d05252038e421e82bff18b67dc14b90d9c3c2f422cd5c4dd4598e1a44b9f200000000000000800000000000000000000000000000000000000000000000000000000000000000000000000000000080020000'
 100 }, _check=100)