blkreader.py

SUBMITTED BY: Guest

DATE: Oct. 16, 2012, 12:24 a.m.

FORMAT: Python

SIZE: 4.9 kB

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  1. # Python 2.5
  2. # I made this and I'm releasing it to the public domain.
  3. # also check http://www.bitbin.it/AJUiYzbX
  5. import time, hashlib
  7. def hash256(x): return hashlib.sha256(hashlib.sha256(x).digest()).digest()
  9. class fstring(): # file methods for strings
  11. def __init__(self, somestring):
  12. self.pos=0
  13. self.string=somestring
  15. def read(self, length=None):
  16. if length==None: length=len(self.string)
  17. out=self.string[self.pos:self.pos+length]; self.pos+=length
  18. return out
  20. def seek(self, point): self.pos=point
  22. def tell(self): return self.pos
  24. class txinput():
  26. def __init__(self, handle):
  28. if type(handle)==str: handle=fstring(handle)
  29. startingpos = handle.tell()
  31. self.prevouthash = handle.read(32)[::-1].encode('hex')
  32. self.prevoutn = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  34. if self.prevouthash=='0'*64:
  35. self.coinbasesize = ord(handle.read(1))
  36. if self.coinbasesize>=253: self.coinbasesize = sum([ord(handle.read(1))*(256**x) for x in range(2*(self.coinbasesize-252))])
  37. self.coinbase = handle.read(self.coinbasesize)
  38. self.sequence = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  40. else:
  41. self.scriptsize = ord(handle.read(1))
  42. if self.scriptsize>=253: self.scriptsize = sum([ord(handle.read(1))*(256**x) for x in range(2*(self.scriptsize-252))])
  43. self.script = handle.read(self.scriptsize)
  44. self.sequence = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  46. class txoutput():
  48. def __init__(self, handle):
  50. if type(handle)==str: handle=fstring(handle)
  51. startingpos = handle.tell()
  53. self.value = sum([ord(handle.read(1))*(256**x) for x in range(8)])
  54. self.scriptsize = ord(handle.read(1))
  55. if self.scriptsize>=253: self.scriptsize = sum([ord(handle.read(1))*(256**x) for x in range(2*(self.scriptsize-252))])
  56. self.script = handle.read(self.scriptsize)
  57. #self.asm
  59. class transaction():
  61. def __init__(self, handle):
  63. if type(handle)==str: handle=fstring(handle)
  64. startingpos = handle.tell()
  66. self.version = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  67. self.numinputs = ord(handle.read(1))
  68. if self.numinputs>=253: self.numinputs = sum([ord(handle.read(1))*(256**x) for x in range(2*(self.numinputs-252))])
  69. self.inputs = [txinput(handle) for inputnum in range(self.numinputs)]
  70. self.numoutputs = ord(handle.read(1))
  71. if self.numoutputs>=253: self.numoutputs = sum([ord(handle.read(1))*(256**x) for x in range(2*(self.numoutputs-252))])
  72. self.outputs = [txoutput(handle) for outputnum in range(self.numoutputs)]
  73. self.locktime = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  74. self.size = handle.tell() - startingpos; handle.seek(startingpos)
  75. self.raw = handle.read(self.size)
  76. self.hash = hash256(self.raw)[::-1].encode('hex')
  78. class block():
  80. def __init__(self, handle):
  82. if type(handle)==str: handle=fstring(handle)
  83. self.unknown = handle.read(8) # I don't know what this is
  84. startingpos = handle.tell()
  86. self.version = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  87. self.prevblock = handle.read(32)[::-1].encode('hex')
  88. self.merkleroot = handle.read(32)[::-1].encode('hex')
  89. self.timestamp = time.gmtime(sum([ord(handle.read(1))*(256**x) for x in range(4)]))
  90. self.bits = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  91. self.nonce = sum([ord(handle.read(1))*(256**x) for x in range(4)])
  93. handle.seek(startingpos)
  94. self.header = handle.read(80)
  95. self.hash = hash256(self.header)[::-1].encode('hex')
  97. self.txcount = ord(handle.read(1))
  98. if self.txcount>=253: self.txcount = sum([ord(handle.read(1))*(256**x) for x in range(2*(self.txcount-252))])
  99. self.tx = [transaction(handle) for txn in range(self.txcount)]
  100. self.size = handle.tell() - startingpos; handle.seek(startingpos)
  101. self.raw = handle.read(self.size)
  102. #self.merkletree
  103. #self.isvalid() to verify merkle tree, hash, and difficulty
  105. class blkfile():
  106. def __init__(self, filename): self.file=file(filename,'rb+')
  107. def tell(self): return self.file.tell()
  108. def getblock(self): return block(self.file)
  109. def readblock(self): return block(self.file).raw
  111. # small demo
  112. # defrag file if getblock is too slow. or simply copy in the same dir, delete original, and rename copy.
  113. #blk0001=blkfile('some directory/blk0001.dat') # change this
  114. #genesisblock=blk0001.getblock()
  115. #for property in ['hash','prevblock','merkleroot','bits','nonce','version','txcount','timestamp','size']:
  116. # print property,':',vars(genesisblock)[property]
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