root / pithos / lib / hashmap.py @ 5a96180b
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# Copyright 2011 GRNET S.A. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or
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# without modification, are permitted provided that the following
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# conditions are met:
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#
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# 1. Redistributions of source code must retain the above
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# copyright notice, this list of conditions and the following
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# disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following
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# disclaimer in the documentation and/or other materials
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# provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and
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# documentation are those of the authors and should not be
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# interpreted as representing official policies, either expressed
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# or implied, of GRNET S.A.
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import hashlib |
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from binascii import hexlify |
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def file_read_iterator(fp, size=1024): |
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while True: |
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data = fp.read(size) |
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if not data: |
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break
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yield data
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class HashMap(list): |
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def __init__(self, blocksize, blockhash): |
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super(HashMap, self).__init__() |
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self.blocksize = blocksize
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self.blockhash = blockhash
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def _hash_raw(self, v): |
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h = hashlib.new(self.blockhash)
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h.update(v) |
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return h.digest()
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def _hash_block(self, v): |
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return self._hash_raw(v.rstrip('\x00')) |
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def hash(self): |
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if len(self) == 0: |
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return self._hash_raw('') |
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if len(self) == 1: |
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return self.__getitem__(0) |
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h = list(self) |
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s = 2
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while s < len(h): |
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s = s * 2
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h += [('\x00' * len(h[0]))] * (s - len(h)) |
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while len(h) > 1: |
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h = [self._hash_raw(h[x] + h[x + 1]) for x in range(0, len(h), 2)] |
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return h[0] |
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def load(self, fp): |
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self.size = 0 |
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for block in file_read_iterator(fp, self.blocksize): |
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self.append(self._hash_block(block)) |
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self.size += len(block) |
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def merkle(path, blocksize=4194304, blockhash='sha256'): |
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hashes = HashMap(blocksize, blockhash) |
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hashes.load(open(path))
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return hexlify(hashes.hash())
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