# -*- coding: iso-8859-1 -*-
""" crypto.hash.sha1Hash

    Wrapper for python sha module to support crypo module standard interface

    Copyright © (c) 2002 by Paul A. Lambert
    Read LICENSE.txt for license information.
"""
import sha
from crypto.hash.hash import Hash

class SHA1(Hash):

    def __init__( self ):
        self.name = 'SHA1'
        self.blocksize      = 1   # single octets can be hashed by padding to raw block size
        self.raw_block_size = 64  # SHA1 operates on 512 bit / 64 byte blocks
        self.digest_size    = 20  # or 160 bits
        self.reset()

    def reset(self):
        self.pysha1 = sha.new()

    def update(self,data):
        """ Update the sha object with the string arg. Repeated calls are
            equivalent to a single call with the concatenation of all the
            arguments: m.update(a); m.update(b) is equivalent to m.update(a+b).
        """
        self.pysha1.update(data)

    def digest(self):
        """ Return the digest of the strings passed to the update()
            method so far. This is a 20-byte string which may contain
            non-ASCII characters, including null bytes.
        """
        return self.pysha1.digest()