mdw@git.distorted.org.uk Git - mLib-python/blob - unihash.pyx

   1 ### -*-pyrex-*-
   2 ###
   3 ### Universal hashing interface
   4 ###
   5 ### (c) 2005 Straylight/Edgeware
   6 ###
   7
   8 ###----- Licensing notice ---------------------------------------------------
   9 ###
  10 ### This file is part of the Python interface to mLib.
  11 ###
  12 ### mLib/Python is free software; you can redistribute it and/or modify
  13 ### it under the terms of the GNU General Public License as published by
  14 ### the Free Software Foundation; either version 2 of the License, or
  15 ### (at your option) any later version.
  16 ###
  17 ### mLib/Python is distributed in the hope that it will be useful,
  18 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ### GNU General Public License for more details.
  21 ###
  22 ### You should have received a copy of the GNU General Public License
  23 ### along with mLib/Python; if not, write to the Free Software Foundation,
  24 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25
  26 def setglobalkey(uint32 k):
  27   """setglobalkey(K): set global hash key"""
  28   unihash_setkey(&unihash_global, k)
  29
  30 cdef class Key:
  31   """Key(K): universal hashing key"""
  32   cdef unihash_info _i
  33   cdef uint32 _k
  34   def __cinit__(me, uint32 k):
  35     unihash_setkey(&me._i, k)
  36     me._k = k
  37   property k:
  38     """K.k -> INT: the key value"""
  39     def __get__(me):
  40       return _u32(me._k)
  41
  42 cdef class Unihash:
  43   """Unihash([key = None]): universal hashing context"""
  44   cdef uint32 _a
  45   cdef readonly Key key
  46   cdef unihash_info *_i
  47   def __cinit__(me, key = None):
  48     cdef Key k
  49     me.key = key
  50     if key is None:
  51       me._i = &unihash_global
  52     else:
  53       k = key
  54       me._i = &k._i
  55     me._a = UNIHASH_INIT(me._i)
  56   def chunk(me, data):
  57     """U.chunk(STR): hash the STR"""
  58     cdef void *p
  59     cdef Py_ssize_t n
  60     PyObject_AsReadBuffer(data, <cvp *>&p, &n)
  61     me._a = unihash_hash(me._i, me._a, p, n)
  62   def done(me):
  63     """U.done() -> INT: the hash of the data"""
  64     return _u32(me._a)
  65
  66 ###----- That's all, folks --------------------------------------------------