#########################################################

# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb 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 Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""

XXX clarify this header

"""

# md5crypt.py

#

# 0423.2000 by michal wallace http://www.sabren.com/

# based on perl's Crypt::PasswdMD5 by Luis Munoz (lem@cantv.net)

# based on /usr/src/libcrypt/crypt.c from FreeBSD 2.2.5-RELEASE

#

# MANY THANKS TO

#

#  Carey Evans - http://home.clear.net.nz/pages/c.evans/

#  Dennis Marti - http://users.starpower.net/marti1/

#

#  For the patches that got this thing working!

#

# modification by logilab:

# * remove usage of the string module

# * don't include the magic string in the output string

#   for true crypt.crypt compatibility

#########################################################

"""md5crypt.py - Provides interoperable MD5-based crypt() function

SYNOPSIS

        import md5crypt.py

        cryptedpassword = md5crypt.md5crypt(password, salt);

DESCRIPTION

unix_md5_crypt() provides a crypt()-compatible interface to the

rather new MD5-based crypt() function found in modern operating systems.

It's based on the implementation found on FreeBSD 2.2.[56]-RELEASE and

contains the following license in it:

 "THE BEER-WARE LICENSE" (Revision 42):

 <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you

 can do whatever you want with this stuff. If we meet some day, and you think

 this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp

"""

MAGIC = '$1$'                        # Magic string

ITOA64 = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

import md5

def to64 (v, n):

    ret = ''

    while (n - 1 >= 0):

        n = n - 1

        ret = ret + ITOA64[v & 0x3f]

        v = v >> 6

    return ret

def crypt(pw, salt, magic=None):

    if isinstance(pw, unicode):

        pw = pw.encode('utf-8')

    if magic is None:

        magic = MAGIC

    # Take care of the magic string if present

    if salt[:len(magic)] == magic:

        salt = salt[len(magic):]

    # salt can have up to 8 characters:

    salt = salt.split('$', 1)[0]

    salt = salt[:8]

    ctx = pw + magic + salt

    final = md5.md5(pw + salt + pw).digest()

    for pl in xrange(len(pw), 0, -16):

        if pl > 16:

            ctx = ctx + final[:16]

        else:

            ctx = ctx + final[:pl]

    # Now the 'weird' xform (??)

    i = len(pw)

    while i:

        if i & 1:

            ctx = ctx + chr(0)  #if ($i & 1) { $ctx->add(pack("C", 0)); }

        else:

            ctx = ctx + pw[0]

        i = i >> 1

    final = md5.md5(ctx).digest()

    # The following is supposed to make

    # things run slower.

    # my question: WTF???

    for i in xrange(1000):

        ctx1 = ''

        if i & 1:

            ctx1 = ctx1 + pw

        else:

            ctx1 = ctx1 + final[:16]

        if i % 3:

            ctx1 = ctx1 + salt

        if i % 7:

            ctx1 = ctx1 + pw

        if i & 1:

            ctx1 = ctx1 + final[:16]

        else:

            ctx1 = ctx1 + pw

        final = md5.md5(ctx1).digest()

    # Final xform

    passwd = ''

    passwd = passwd + to64((int(ord(final[0])) << 16)

                           |(int(ord(final[6])) << 8)

                           |(int(ord(final[12]))),4)

    passwd = passwd + to64((int(ord(final[1])) << 16)

                           |(int(ord(final[7])) << 8)

                           |(int(ord(final[13]))), 4)

    passwd = passwd + to64((int(ord(final[2])) << 16)

                           |(int(ord(final[8])) << 8)

                           |(int(ord(final[14]))), 4)

    passwd = passwd + to64((int(ord(final[3])) << 16)

                           |(int(ord(final[9])) << 8)

                           |(int(ord(final[15]))), 4)

    passwd = passwd + to64((int(ord(final[4])) << 16)

                           |(int(ord(final[10])) << 8)

                           |(int(ord(final[5]))), 4)

    passwd = passwd + to64((int(ord(final[11]))), 2)

    return salt + '$' + passwd