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/pypy/module/binascii/interp_crc32.py

https://bitbucket.org/pypy/pypy/
Python | 12 lines | 10 code | 2 blank | 0 comment | 0 complexity | b383b83724d161fa21144d2cb6b89e01 MD5 | raw file
Possible License(s): AGPL-3.0, BSD-3-Clause, Apache-2.0 
    

  1. from pypy.interpreter.gateway import unwrap_spec
    2. 

  2. from rpython.rtyper.lltypesystem import rffi
    3. 

  3. from rpython.rlib.rarithmetic import r_uint, intmask
    4. 

  4. from rpython.rlib import rzipfile
    5. 

  5. 

  6. @unwrap_spec(data='bufferstr', oldcrc='truncatedint_w')
    7. 

  7. def crc32(space, data, oldcrc=0):
    8. 

  8.     "Compute the CRC-32 incrementally."
    9. 

  9. 

  10.     crc = rzipfile.crc32(data, r_uint(oldcrc))
    11. 

  11.     crc = rffi.cast(rffi.INT, crc)    # unsigned => 32-bit signed
    12. 

  12.     return space.wrap(intmask(crc))
    13. 

  13.