dft_tools/triqs/arrays/indexmaps/range.hpp

/*******************************************************************************
 *
 * TRIQS: a Toolbox for Research in Interacting Quantum Systems
 *
 * Copyright (C) 2011 by O. Parcollet
 *
 * TRIQS 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 3 of the License, or (at your option) any later
 * version.
 *
 * TRIQS 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
 * TRIQS. If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#ifndef TRIQS_ARRAYS_RANGE_H
#define TRIQS_ARRAYS_RANGE_H
#include <ostream>

namespace triqs { namespace arrays { 

 /**
  */
 class range {
  std::ptrdiff_t first_, last_, step_;
  public:

  typedef std::ptrdiff_t index_type;

  range():first_(0),last_(-1),step_(1) {} // i.e. all
  range(const range& r):first_(r.first_), last_(r.last_), step_(r.step_) {}
  range(std::ptrdiff_t first__, std::ptrdiff_t last__, std::ptrdiff_t step__=1):first_(first__), last_(last__), step_(step__) {}

  std::ptrdiff_t first() const { return first_;}
  std::ptrdiff_t last () const { return last_;}
  std::ptrdiff_t step() const { return step_;}
  size_t size() const { std::ptrdiff_t r = (last_ - first_ + 1)/step_; if (r<0) TRIQS_RUNTIME_ERROR <<" range with negative size"; return size_t(r);}

  range operator+(std::ptrdiff_t shift) const { return range(first_ + shift, last_ + shift, step_); }

  friend inline std::ostream& operator<<(std::ostream& os, const range& range) {
   os << "range(" << range.first() << "," << range.last() << "," << range.step() << ")"; 
   return os;
  }
 };

 /**
  */
 class ellipsis : public range { 
  public :
   ellipsis( std::ptrdiff_t first__, std::ptrdiff_t last__, std::ptrdiff_t step__=1): range(first__, last__, step__) {}
   ellipsis() : range() {}
 };

}}//namespace triqs::arrays  
#endif