// libTorrent - BitTorrent library
// Copyright (C) 2005-2007, Jari Sundell
//
// 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 of the License, 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, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// In addition, as a special exception, the copyright holders give
// permission to link the code of portions of this program with the
// OpenSSL library under certain conditions as described in each
// individual source file, and distribute linked combinations
// including the two.
//
// You must obey the GNU General Public License in all respects for
// all of the code used other than OpenSSL.  If you modify file(s)
// with this exception, you may extend this exception to your version
// of the file(s), but you are not obligated to do so.  If you do not
// wish to do so, delete this exception statement from your version.
// If you delete this exception statement from all source files in the
// program, then also delete it here.
//
// Contact:  Jari Sundell <jaris@ifi.uio.no>
//
//           Skomakerveien 33
//           3185 Skoppum, NORWAY

// A fixed with char array used to store 20 byte with hashes. This
// should really be replaced with std::array<20>.

#ifndef LIBTORRENT_HASH_STRING_H
#define LIBTORRENT_HASH_STRING_H

#include <cstring>
#include <string>
#include <iterator>
#include <torrent/common.h>

namespace torrent {

class LIBTORRENT_EXPORT HashString {
public:
  typedef char                                    value_type;
  typedef value_type&                             reference;
  typedef const value_type&                       const_reference;
  typedef value_type*                             iterator;
  typedef const value_type*                       const_iterator;
  typedef std::size_t                             size_type;
  typedef std::ptrdiff_t                          difference_type;
  typedef std::reverse_iterator<iterator>         reverse_iterator;
  typedef std::reverse_iterator<const_iterator>   const_reverse_iterator;

  static const size_type size_data = 20;

  size_type           size() const                      { return size_data; }

  iterator            begin()                           { return m_data; }
  const_iterator      begin() const                     { return m_data; }

  iterator            end()                             { return m_data + size(); }
  const_iterator      end() const                       { return m_data + size(); }

  reverse_iterator       rbegin()                       { return reverse_iterator(end()); }
  const_reverse_iterator rbegin() const                 { return const_reverse_iterator(end()); }

  reverse_iterator       rend()                         { return reverse_iterator(begin()); }
  const_reverse_iterator rend() const                   { return const_reverse_iterator(begin()); }

  reference           operator [] (size_type n)         { return *(m_data + n); }
  const_reference     operator [] (size_type n) const   { return *(m_data + n); }

  value_type*         data()                            { return m_data; }
  const value_type*   data() const                      { return m_data; }

  const value_type*   c_str() const                     { return m_data; }

  std::string         str() const                       { return std::string(m_data, size_data); }

  void                clear(int v = 0)                  { std::memset(data(), v, size()); }

  void                assign(const value_type* src)     { std::memcpy(data(), src, size()); }

  bool                equal_to(const char* hash) const     { return std::memcmp(m_data, hash, size()) == 0; }
  bool                not_equal_to(const char* hash) const { return std::memcmp(m_data, hash, size()) != 0; }

  // It is the users responsibility to ensure src.length() >=
  // size_data.
  static const HashString* cast_from(const char* src)        { return (const HashString*)src; }
  static const HashString* cast_from(const std::string& src) { return (const HashString*)src.c_str(); }

  static HashString*  cast_from(char* src)                   { return (HashString*)src; }

private:
  char                m_data[size_data];
};

inline bool
operator == (const HashString& one, const HashString& two) {
  return std::memcmp(one.begin(), two.begin(), HashString::size_data) == 0;
}

inline bool
operator != (const HashString& one, const HashString& two) {
  return std::memcmp(one.begin(), two.begin(), HashString::size_data) != 0;
}

inline bool
operator < (const HashString& one, const HashString& two) {
  return std::memcmp(one.begin(), two.begin(), HashString::size_data) < 0;
}

inline bool
operator <= (const HashString& one, const HashString& two) {
  return std::memcmp(one.begin(), two.begin(), HashString::size_data) <= 0;
}

}

#endif
