1 // Copyright 2002 The Trustees of Indiana University.
3 // Use, modification and distribution is subject to the Boost Software
4 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
5 // http://www.boost.org/LICENSE_1_0.txt)
7 // Boost.MultiArray Library
8 // Authors: Ronald Garcia
11 // See http://www.boost.org/libs/multi_array for documentation.
13 #ifndef BOOST_INDEX_RANGE_RG071801_HPP
14 #define BOOST_INDEX_RANGE_RG071801_HPP
16 #include <boost/config.hpp>
18 #include <boost/limits.hpp>
20 // For representing intervals, also with stride.
21 // A degenerate range is a range with one element.
23 // Thanks to Doug Gregor for the really cool idea of using the
24 // comparison operators to express various interval types!
26 // Internally, we represent the interval as half-open.
30 namespace multi_array {
32 template <typename Index,typename SizeType>
36 typedef SizeType size_type;
39 static index from_start()
40 { return (std::numeric_limits<index>::min)(); }
43 { return (std::numeric_limits<index>::max)(); }
49 start_ = from_start();
55 explicit index_range(index pos)
63 explicit index_range(index start, index finish, index stride=1)
64 : start_(start), finish_(finish), stride_(stride),
69 // These are for chaining assignments to an index_range
70 index_range& start(index s) {
76 index_range& finish(index f) {
82 index_range& stride(index s) { stride_ = s; return *this; }
89 index get_start(index low_index_range = index_range::from_start()) const
91 if (start_ == from_start())
92 return low_index_range;
101 index get_finish(index high_index_range = index_range::to_end()) const
103 if (finish_ == to_end())
104 return high_index_range;
108 index stride() const { return stride_; }
110 void set_index_range(index start, index finish, index stride=1)
117 static index_range all()
118 { return index_range(from_start(), to_end(), 1); }
120 bool is_degenerate() const { return degenerate_; }
122 index_range operator-(index shift) const
124 return index_range(start_ - shift, finish_ - shift, stride_);
127 index_range operator+(index shift) const
129 return index_range(start_ + shift, finish_ + shift, stride_);
132 index operator[](unsigned i) const
134 return start_ + i * stride_;
137 index operator()(unsigned i) const
139 return start_ + i * stride_;
142 // add conversion to std::slice?
145 index start_, finish_, stride_;
149 // Express open and closed interval end-points using the comparison
153 template <typename Index, typename SizeType>
154 inline index_range<Index,SizeType>
155 operator<=(Index s, const index_range<Index,SizeType>& r)
157 return index_range<Index,SizeType>(s, r.finish(), r.stride());
161 template <typename Index, typename SizeType>
162 inline index_range<Index,SizeType>
163 operator<(Index s, const index_range<Index,SizeType>& r)
165 return index_range<Index,SizeType>(s + 1, r.finish(), r.stride());
169 template <typename Index, typename SizeType>
170 inline index_range<Index,SizeType>
171 operator<(const index_range<Index,SizeType>& r, Index f)
173 return index_range<Index,SizeType>(r.start(), f, r.stride());
177 template <typename Index, typename SizeType>
178 inline index_range<Index,SizeType>
179 operator<=(const index_range<Index,SizeType>& r, Index f)
181 return index_range<Index,SizeType>(r.start(), f + 1, r.stride());
184 } // namespace multi_array
185 } // namespace detail
188 #endif // BOOST_INDEX_RANGE_RG071801_HPP