// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
// 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/>.
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#include "hash_block.h"

namespace mobius
{
namespace crypt
{
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief constructor
//! \param block_size cipher block size in bytes
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
hash_block::hash_block (std::size_t block_size)
  : data_ (block_size),
    block_size_ (block_size),
    idx_ (0)
{
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief update hash for a given block
//! \param data bytearray
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
void
hash_block::update (const mobius::bytearray& data) noexcept
{
  mobius::bytearray::size_type pos = 0;
  mobius::bytearray::size_type len = data.size ();

  while (pos < len)
    {
      mobius::bytearray::size_type count = std::min (block_size_ - idx_, len - pos);
      std::copy (data.begin () + pos, data.begin () + pos + count, data_.begin () + idx_);
      idx_ += count;
      pos += count;

      if (idx_ == block_size_)
        {
          _update_block (data_);
          idx_ = 0;
        }
    }
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief reset hash value
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
void
hash_block::reset () noexcept
{
  idx_ = 0;
  digest_.clear ();
  _reset ();
}

// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
//! \brief generate final hash value
//! \return digest
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
const mobius::bytearray
hash_block::get_digest ()
{
  if (digest_.empty ())
    {
      if (idx_ > 0)
        {
          digest_ = _evaluate (data_.slice (0, idx_ - 1));
        }

      else
        {
          digest_ = _evaluate (mobius::bytearray ());
        }
    }

  return digest_;
}

} // namespace crypt
} // namespace mobius
