mdw@git.distorted.org.uk Git - mLib-python/blob - crc32.pyx

   1 ### -*-pyrex-*-
   2 ###
   3 ### Cyclic redundancy checker
   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 cdef class CRC32:
  27   """CRC32(): calculate CRC32 of a stream"""
  28   cdef uint32 _a
  29   def __cinit__(me, *hunoz, **hukairz):
  30     me._a = 0
  31   def __init__(me):
  32     pass
  33   def chunk(me, data):
  34     """C.chunk(STR): process another chunk of input"""
  35     cdef void *p
  36     cdef Py_ssize_t n
  37     PyObject_AsReadBuffer(data, <cvp *>&p, &n)
  38     me._a = c_crc32(me._a, p, n)
  39     return me
  40   def done(me):
  41     """C.done() -> INT: return CRC of data"""
  42     return _u32(me._a)
  43
  44 def crc32(data):
  45   """crc32(STR) -> INT"""
  46   cdef void *p
  47   cdef Py_ssize_t n
  48   cdef uint32 c
  49   PyObject_AsReadBuffer(data, <cvp *>&p, &n)
  50   c = c_crc32(0, p, n)
  51   return _u32(c)
  52
  53 ###----- That's all, folks --------------------------------------------------