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