Initial import.

[mLib-python] / crc32.pyx

# -*-pyrex-*-
#
# $Id$
#
# Cyclic redundancy checker
#
# (c) 2005 Straylight/Edgeware
#

#----- Licensing notice -----------------------------------------------------
#
# This file is part of the Python interface to mLib.
#
# mLib/Python is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# 
# mLib/Python is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with mLib/Python; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

cdef extern from 'mLib/crc32.h':
  ctypedef int uint32
  uint32 c_crc32 "crc32" (uint32 a, void *p, int sz)

cdef extern from 'limits.h':
  enum:
    LONG_MAX

cdef extern from 'Python.h':
  int PyObject_AsReadBuffer(obj, void **buf, int *len) except -1
  PyInt_FromLong(long i)
  PyLong_FromUnsignedLong(unsigned long i)

cdef _u32(uint32 x):
  if x < LONG_MAX:
    return PyInt_FromLong(x)
  else:
    return PyLong_FromUnsignedLong(x)

cdef class CRC32:
  cdef uint32 _a
  def __new__(me, *hunoz, **hukairz):
    me._a = 0
  def __init__(me):
    pass
  def chunk(me, data):
    cdef void *p
    cdef int n
    PyObject_AsReadBuffer(data, &p, &n)
    me._a = c_crc32(me._a, p, n)
    return me
  def done(me):
    return _u32(me._a)

def crc32(data):
  cdef void *p
  cdef int n
  cdef uint32 c
  PyObject_AsReadBuffer(data, &p, &n)
  c = c_crc32(0, p, n)
  return _u32(c)

#----- That's all, folks ----------------------------------------------------