# =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
# Mobius Forensic Toolkit
# Copyright (C) 2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 Eduardo Aguiar
#
# 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. If not, see <http://www.gnu.org/licenses/>.
# =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
import mobius
import binascii

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# Constants
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CANCELLED_HEADER_OLD = 0x0e
CANCELLED_HEADER = 0x0f
CANCELLED_VERSION = 0x01

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# @brief generic data holder
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class dataholder (object):
  pass

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# @brief Decode data from Cancelled.met
# @see CKnownFileList::LoadCancelledFiles - srchybrid/KnownFileList.cpp
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def decode (f):

  # try to open file
  reader = f.new_reader ()
  if not reader:
    return

  # decode header
  decoder = mobius.decoder.data_decoder (reader)

  header = decoder.get_uint8 ()
  if header not in (CANCELLED_HEADER, CANCELLED_HEADER_OLD):
    return

  if header == CANCELLED_HEADER:
    version = decoder.get_uint8 ()

    if version > CANCELLED_VERSION:
      mobius.core.log ("p2p.emule.decoder_cancelled_met.py: Version %d > %d" % (version, CANCELLED_VERSION))

    seed = decoder.get_uint32_le ()

  # decode entries
  data = dataholder ()
  data.entries = []
  count = decoder.get_uint32_le ()
  
  for i in xrange (count):
    entry = dataholder ()
    entry.hash_ed2k = binascii.hexlify (decoder.get_bytearray_by_size (16))
    entry.tags = []

    tag_count = decoder.get_uint8 ()

    for j in xrange (tag_count):
      tag = CTag.decode (decoder)
      entry.tags.append (tag)

    if header == CANCELLED_HEADER_OLD:
      pass # @todo convert old hash to new hash
      
    data.entries.append (entry)

  # return data
  return data
