# Copyright (C) 2004 Nicolas Delon <nicolas@prelude-ids.org>
# All Rights Reserved
#
# This file is part of the Prelude program.
#
# This program 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, or (at your option)
# any later version.
#
# This program 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 this program; see the file COPYING.  If not, write to
# the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


def compute_file_digest(filename, digest):
    BLOCK_SIZE = 32768
    
    file = open(filename)
    while True:
        data = file.read(BLOCK_SIZE)
        digest.update(data)
        if len(data) < BLOCK_SIZE:
            break
    file.close()
    return digest.hexdigest()

def compute_content_digest(content, digest):
    return digest.new(content).hexdigest()


# use the fastest md5 implementation available

try:
    import fchksum

    def md5_file_digest(filename):
        return fchksum.fmd5t(filename)[0]

except ImportError:
    import md5

    def md5_file_digest(filename):
        return compute_file_digest(filename, md5.new())


import md5

def md5_content_digest(content):
    return compute_content_digest(content, md5)


import sha

def sha_file_digest(filename):
    return compute_file_digest(filename, sha.new())

def sha_content_digest(filename):
    return compute_content_digest(filename, sha)