rtorrent/rak/ranges.h

// rak - Rakshasa's toolbox
// Copyright (C) 2005-2006, 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

#ifndef RAK_RANGES_H
#define RAK_RANGES_H

#include <algorithm>
#include <vector>
#include <rak/functional.h>

namespace rak {

template <typename Type>
class ranges : private std::vector<std::pair<Type, Type> > {
public:
  typedef std::vector<std::pair<Type, Type> > Base;
  typedef typename Base::value_type           value_type;
  typedef typename Base::reference            reference;
  typedef typename Base::iterator             iterator;
  typedef typename Base::const_iterator       const_iterator;
  typedef typename Base::reverse_iterator     reverse_iterator;

  using Base::clear;
  using Base::size;
  using Base::begin;
  using Base::end;
  using Base::rbegin;
  using Base::rend;

  void                insert(Type first, Type last) { insert(std::make_pair(first, last)); }
//   void                erase(Type first, Type last)  { erase(std::make_pair(first, last)); }

  void                insert(value_type r);
//   void                erase(value_type r);

  // Find the first ranges that has an end greater than index.
  iterator            find(Type index);
  const_iterator      find(Type index) const;

  // Use find with no closest match.
  bool                has(Type index) const;

private:
  void                unify(iterator itr);
};

template <typename Type>
void
ranges<Type>::insert(value_type r) {
  if (r.first >= r.second)
    return;

  iterator first = std::find_if(begin(), end(), rak::less_equal(r.first, rak::mem_ptr_ref(&value_type::second)));

  if (first == end() || r.second < first->first) {
    // The new range is before the first, after the last or between
    // two ranges.
    Base::insert(first, r);
    return;
  }
  
  first->first = std::min(r.first, first->first);
  first->second = std::max(r.second, first->second);

  unify(first);
}

// template <typename Type>
// void
// ranges<Type>::erase(value_type r) {
// }

// Find the first ranges that has an end greater than index.
template <typename Type>
inline typename ranges<Type>::iterator
ranges<Type>::find(Type index) {
  return std::find_if(begin(), end(), rak::less(index, rak::mem_ptr_ref(&value_type::second)));
}

template <typename Type>
inline typename ranges<Type>::const_iterator
ranges<Type>::find(Type index) const {
  return std::find_if(begin(), end(), rak::less(index, rak::mem_ptr_ref(&value_type::second)));
}

// Use find with no closest match.
template <typename Type>
inline bool
ranges<Type>::has(Type index) const {
  const_iterator itr = find(index);

  return itr != end() && index >= itr->first;
}

template <typename Type>
inline void
ranges<Type>::unify(iterator first) {
  iterator last = std::find_if((first + 1), end(), rak::less(first->second, rak::mem_ptr_ref(&value_type::first)));

  first->second = std::max(first->second, (last - 1)->second);
  Base::erase((first + 1), last);
}

}

#endif