Chris@16: // Copyright 2002 The Trustees of Indiana University.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software 
Chris@16: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  Boost.MultiArray Library
Chris@16: //  Authors: Ronald Garcia
Chris@16: //           Jeremy Siek
Chris@16: //           Andrew Lumsdaine
Chris@16: //  See http://www.boost.org/libs/multi_array for documentation.
Chris@16: 
Chris@16: #ifndef BOOST_INDEX_RANGE_RG071801_HPP
Chris@16: #define BOOST_INDEX_RANGE_RG071801_HPP
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <utility>
Chris@16: #include <boost/limits.hpp>
Chris@16: 
Chris@16: // For representing intervals, also with stride.
Chris@16: // A degenerate range is a range with one element.
Chris@16: 
Chris@16: // Thanks to Doug Gregor for the really cool idea of using the
Chris@16: // comparison operators to express various interval types!
Chris@16: 
Chris@16: // Internally, we represent the interval as half-open.
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace detail {
Chris@16: namespace multi_array {
Chris@16: 
Chris@16:   template <typename Index,typename SizeType>
Chris@16:   class index_range {
Chris@16:   public:
Chris@16:     typedef Index index;
Chris@16:     typedef SizeType size_type;
Chris@16: 
Chris@16:   private:
Chris@16:     static index from_start()
Chris@16:       { return (std::numeric_limits<index>::min)(); }
Chris@16: 
Chris@16:     static index to_end()
Chris@16:       { return (std::numeric_limits<index>::max)(); }
Chris@16: 
Chris@16:   public:
Chris@16: 
Chris@16:     index_range()
Chris@16:     {
Chris@16:       start_ = from_start();
Chris@16:       finish_ = to_end();
Chris@16:       stride_ = 1;
Chris@16:       degenerate_ = false;
Chris@16:     }
Chris@16: 
Chris@16:     explicit index_range(index pos)
Chris@16:     {
Chris@16:       start_ = pos;
Chris@16:       finish_ = pos+1;
Chris@16:       stride_ = 1;
Chris@16:       degenerate_ = true;
Chris@16:     }
Chris@16: 
Chris@16:     explicit index_range(index start, index finish, index stride=1)
Chris@16:       : start_(start), finish_(finish), stride_(stride),
Chris@16:         degenerate_(false)
Chris@16:     { }
Chris@16: 
Chris@16: 
Chris@16:     // These are for chaining assignments to an index_range
Chris@16:     index_range& start(index s) {
Chris@16:       start_ = s;
Chris@16:       degenerate_ = false;
Chris@16:       return *this;
Chris@16:     }
Chris@16: 
Chris@16:     index_range& finish(index f) {
Chris@16:       finish_ = f;
Chris@16:       degenerate_ = false;
Chris@16:       return *this;
Chris@16:     }
Chris@16: 
Chris@16:     index_range& stride(index s) { stride_ = s; return *this; }
Chris@16: 
Chris@16:     index start() const
Chris@16:     { 
Chris@16:       return start_; 
Chris@16:     }
Chris@16: 
Chris@16:     index get_start(index low_index_range = index_range::from_start()) const
Chris@16:     { 
Chris@16:       if (start_ == from_start())
Chris@16:         return low_index_range;
Chris@16:       return start_; 
Chris@16:     }
Chris@16: 
Chris@16:     index finish() const
Chris@16:     {
Chris@16:       return finish_;
Chris@16:     }
Chris@16: 
Chris@16:     index get_finish(index high_index_range = index_range::to_end()) const
Chris@16:     {
Chris@16:       if (finish_ == to_end())
Chris@16:         return high_index_range;
Chris@16:       return finish_;
Chris@16:     }
Chris@16: 
Chris@16:     index stride() const { return stride_; }
Chris@16: 
Chris@16:     void set_index_range(index start, index finish, index stride=1)
Chris@16:     {
Chris@16:       start_ = start;
Chris@16:       finish_ = finish;
Chris@16:       stride_ = stride;
Chris@16:     }
Chris@16: 
Chris@16:     static index_range all() 
Chris@16:     { return index_range(from_start(), to_end(), 1); }
Chris@16: 
Chris@16:     bool is_degenerate() const { return degenerate_; }
Chris@16: 
Chris@16:     index_range operator-(index shift) const
Chris@16:     { 
Chris@16:       return index_range(start_ - shift, finish_ - shift, stride_); 
Chris@16:     }
Chris@16: 
Chris@16:     index_range operator+(index shift) const
Chris@16:     { 
Chris@16:       return index_range(start_ + shift, finish_ + shift, stride_); 
Chris@16:     }
Chris@16: 
Chris@16:     index operator[](unsigned i) const
Chris@16:     {
Chris@16:       return start_ + i * stride_;
Chris@16:     }
Chris@16: 
Chris@16:     index operator()(unsigned i) const
Chris@16:     {
Chris@16:       return start_ + i * stride_;
Chris@16:     }
Chris@16: 
Chris@16:     // add conversion to std::slice?
Chris@16: 
Chris@16:   public:
Chris@16:     index start_, finish_, stride_;
Chris@16:     bool degenerate_;
Chris@16:   };
Chris@16: 
Chris@16:   // Express open and closed interval end-points using the comparison
Chris@16:   // operators.
Chris@16: 
Chris@16:   // left closed
Chris@16:   template <typename Index, typename SizeType>
Chris@16:   inline index_range<Index,SizeType>
Chris@16:   operator<=(Index s, const index_range<Index,SizeType>& r)
Chris@16:   {
Chris@16:     return index_range<Index,SizeType>(s, r.finish(), r.stride());
Chris@16:   }
Chris@16: 
Chris@16:   // left open
Chris@16:   template <typename Index, typename SizeType>
Chris@16:   inline index_range<Index,SizeType>
Chris@16:   operator<(Index s, const index_range<Index,SizeType>& r)
Chris@16:   {
Chris@16:     return index_range<Index,SizeType>(s + 1, r.finish(), r.stride());
Chris@16:   }
Chris@16: 
Chris@16:   // right open
Chris@16:   template <typename Index, typename SizeType>
Chris@16:   inline index_range<Index,SizeType>
Chris@16:   operator<(const index_range<Index,SizeType>& r, Index f)
Chris@16:   {
Chris@16:     return index_range<Index,SizeType>(r.start(), f, r.stride());
Chris@16:   }
Chris@16: 
Chris@16:   // right closed
Chris@16:   template <typename Index, typename SizeType>
Chris@16:   inline index_range<Index,SizeType>
Chris@16:   operator<=(const index_range<Index,SizeType>& r, Index f)
Chris@16:   {
Chris@16:     return index_range<Index,SizeType>(r.start(), f + 1, r.stride());
Chris@16:   }
Chris@16: 
Chris@16: } // namespace multi_array
Chris@16: } // namespace detail  
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_INDEX_RANGE_RG071801_HPP