forked from boostorg/iterator
Inital checkin
[SVN r8813]
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Dave Abrahams
366
include/boost/half_open_range.hpp
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366
include/boost/half_open_range.hpp
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// (C) Copyright Jeremy Siek and David Abrahams 2000-2001. Permission to copy,
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// use, modify, sell and distribute this software is granted provided this
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// copyright notice appears in all copies. This software is provided "as is"
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// without express or implied warranty, and with no claim as to its suitability
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// for any purpose.
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//
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// Revision History:
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// 30 Jan 2001 Initial Checkin (David Abrahams)
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#ifndef BOOST_HALF_OPEN_RANGE_HPP_
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# define BOOST_HALF_OPEN_RANGE_HPP_
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# include <boost/counting_iterator.hpp>
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# include <functional>
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# include <cassert>
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# include <boost/operators.hpp>
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# include <string>
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# include <stdexcept>
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namespace boost {
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namespace detail {
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// Template class choose_finish -- allows us to maintain the invariant that
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// start() <= finish() on half_open_range specializations that support random
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// access.
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template <class Tag>
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struct choose_finish
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{
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template <class T>
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struct rebind
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{
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static T choose(const T&, const T& finish)
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{ return finish; }
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};
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};
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template <>
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struct choose_finish<std::random_access_iterator_tag>
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{
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template <class T>
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struct rebind
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{
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static T choose(const T& start, const T& finish)
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{ return finish < start ? start : finish; }
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};
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};
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}
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template <class Incrementable>
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struct half_open_range
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{
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typedef iterator_adaptor<Incrementable,
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counting_iterator_policies<Incrementable>,
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counting_iterator_traits<Incrementable> > iterator;
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private: // utility type definitions
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typedef std::less<Incrementable> less_value;
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typedef typename boost::detail::iterator_traits<iterator>::iterator_category category;
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public:
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typedef iterator const_iterator;
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typedef typename counting_iterator_traits<Incrementable>::value_type value_type;
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typedef typename counting_iterator_traits<Incrementable>::difference_type difference_type;
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typedef typename counting_iterator_traits<Incrementable>::reference reference;
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typedef typename counting_iterator_traits<Incrementable>::reference const_reference;
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typedef typename counting_iterator_traits<Incrementable>::pointer pointer;
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typedef typename counting_iterator_traits<Incrementable>::pointer const_pointer;
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// It would be nice to select an unsigned type, but this is appropriate
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// since the library makes an attempt to select a difference_type which can
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// hold the difference between any two iterators.
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typedef typename counting_iterator_traits<Incrementable>::difference_type size_type;
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half_open_range(Incrementable start, Incrementable finish)
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: m_start(start),
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m_finish(
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detail::choose_finish<category>::template rebind<Incrementable>::choose(start, finish))
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{}
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// Implicit conversion from std::pair<Incrementable,Incrementable> allows us
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// to accept the results of std::equal_range(), for example.
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half_open_range(const std::pair<Incrementable,Incrementable>& x)
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: m_start(x.first),
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m_finish(
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detail::choose_finish<category>::template rebind<Incrementable>::choose(x.first,x.second))
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{}
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half_open_range& operator=(const std::pair<Incrementable,Incrementable>& x)
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{
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m_start = x.first;
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m_finish =
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detail::choose_finish<category>::template rebind<Incrementable>::choose(x.first,x.second);
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}
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iterator begin() const { return iterator(m_start); }
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iterator end() const { return iterator(m_finish); }
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Incrementable front() const { assert(!this->empty()); return m_start; }
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Incrementable back() const { assert(!this->empty()); return boost::prior(m_finish); }
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Incrementable start() const { return m_start; }
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Incrementable finish() const { return m_finish; }
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size_type size() const { return boost::detail::distance(begin(), end()); }
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bool empty() const
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{
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return m_finish == m_start;
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}
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void swap(half_open_range& x) {
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std::swap(m_start, x.m_start);
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std::swap(m_finish, x.m_finish);
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}
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public: // functions requiring random access elements
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// REQUIRES: x is reachable from this->front()
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bool contains(const value_type& x) const
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{
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BOOST_STATIC_ASSERT((boost::is_same<category, std::random_access_iterator_tag>::value));
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return !less_value()(x, m_start) && less_value()(x, m_finish);
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}
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bool contains(const half_open_range& x) const
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{
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BOOST_STATIC_ASSERT((boost::is_same<category, std::random_access_iterator_tag>::value));
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return x.empty() || !less_value()(x.m_start, m_start) && !less_value()(m_finish, x.m_finish);
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}
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bool intersects(const half_open_range& x) const
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{
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BOOST_STATIC_ASSERT((boost::is_same<category, std::random_access_iterator_tag>::value));
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return less_value()(
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less_value()(this->m_start, x.m_start) ? x.m_start : this->m_start,
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less_value()(this->m_finish, x.m_finish) ? this->m_finish : x.m_finish);
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}
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half_open_range& operator&=(const half_open_range& x)
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{
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BOOST_STATIC_ASSERT((boost::is_same<category, std::random_access_iterator_tag>::value));
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if (less_value()(this->m_start, x.m_start))
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this->m_start = x.m_start;
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if (less_value()(x.m_finish, this->m_finish))
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this->m_finish = x.m_finish;
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if (less_value()(this->m_finish, this->m_start))
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this->m_start = this->m_finish;
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return *this;
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}
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half_open_range& operator|=(const half_open_range& x)
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{
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BOOST_STATIC_ASSERT((boost::is_same<category, std::random_access_iterator_tag>::value));
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if (!x.empty())
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{
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if (this->empty())
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{
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*this = x;
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}
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else
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{
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if (less_value()(x.m_start, this->m_start))
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this->m_start = x.m_start;
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if (less_value()(this->m_finish, x.m_finish))
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this->m_finish = x.m_finish;
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}
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}
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return *this;
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}
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// REQUIRES: x is reachable from this->front()
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const_iterator find(const value_type& x) const
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{
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BOOST_STATIC_ASSERT((boost::is_same<category, std::random_access_iterator_tag>::value));
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return const_iterator(this->contains(x) ? x : m_finish);
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}
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// REQUIRES: index >= 0 && index < size()
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value_type operator[](size_type index) const
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{
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assert(index >= 0 && index < size());
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return m_start + index;
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}
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value_type at(size_type index) const
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{
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if (index < 0 || index >= size())
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throw std::out_of_range(std::string("half_open_range"));
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return m_start + index;
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}
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private: // data members
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Incrementable m_start, m_finish;
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};
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template <class Incrementable>
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half_open_range<Incrementable> operator|(
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half_open_range<Incrementable> x,
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const half_open_range<Incrementable>& y)
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{
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return x |= y;
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}
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template <class Incrementable>
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half_open_range<Incrementable> operator&(
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half_open_range<Incrementable> x,
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const half_open_range<Incrementable>& y)
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{
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return x &= y;
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}
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template <class Incrementable>
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inline bool operator==(
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const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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const bool y_empty = y.empty();
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return x.empty() ? y_empty : !y_empty && x.start() == y.start() && x.finish() == y.finish();
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}
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template <class Incrementable>
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inline bool operator!=(
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const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return !(x == y);
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}
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template <class Incrementable>
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inline half_open_range<Incrementable>
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make_half_open_range(Incrementable first, Incrementable last)
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{
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return half_open_range<Incrementable>(first, last);
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}
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template <class Incrementable>
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bool intersects(
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const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return x.intersects(y);
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}
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template <class Incrementable>
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bool contains(
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const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return x.contains(y);
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}
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} // namespace boost
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#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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namespace std {
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template <class Incrementable> struct less<boost::half_open_range<Incrementable> >
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: binary_function<
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boost::half_open_range<Incrementable>,
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boost::half_open_range<Incrementable>,bool>
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{
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bool operator()(
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const boost::half_open_range<Incrementable>& x,
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const boost::half_open_range<Incrementable>& y) const
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{
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less<Incrementable> cmp;
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return !y.empty() && (
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cmp(x.start(), y.start())
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|| !cmp(y.start(), x.start())
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&& cmp(x.finish(), y.finish()));
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}
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};
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template <class Incrementable> struct less_equal<boost::half_open_range<Incrementable> >
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: binary_function<
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boost::half_open_range<Incrementable>,
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boost::half_open_range<Incrementable>,bool>
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{
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bool operator()(
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const boost::half_open_range<Incrementable>& x,
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const boost::half_open_range<Incrementable>& y) const
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{
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typedef boost::half_open_range<Incrementable> range;
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less<range> cmp;
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return !cmp(y,x);
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}
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};
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template <class Incrementable> struct greater<boost::half_open_range<Incrementable> >
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: binary_function<
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boost::half_open_range<Incrementable>,
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boost::half_open_range<Incrementable>,bool>
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{
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bool operator()(
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const boost::half_open_range<Incrementable>& x,
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const boost::half_open_range<Incrementable>& y) const
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{
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typedef boost::half_open_range<Incrementable> range;
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less<range> cmp;
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return cmp(y,x);
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}
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};
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template <class Incrementable> struct greater_equal<boost::half_open_range<Incrementable> >
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: binary_function<
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boost::half_open_range<Incrementable>,
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boost::half_open_range<Incrementable>,bool>
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{
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bool operator()(
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const boost::half_open_range<Incrementable>& x,
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const boost::half_open_range<Incrementable>& y) const
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{
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typedef boost::half_open_range<Incrementable> range;
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less<range> cmp;
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return !cmp(x,y);
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}
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};
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} // namespace std
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#else
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namespace boost {
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// Can't partially specialize std::less et al, so we must provide the operators
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template <class Incrementable>
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bool operator<(const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return !y.empty() && (
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x.empty() || std::less<Incrementable>()(x.start(), y.start())
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|| !std::less<Incrementable>()(y.start(), x.start())
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&& std::less<Incrementable>()(x.finish(), y.finish()));
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}
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template <class Incrementable>
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bool operator>(const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return y < x;
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}
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template <class Incrementable>
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bool operator<=(const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return !(y < x);
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}
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template <class Incrementable>
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bool operator>=(const half_open_range<Incrementable>& x,
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const half_open_range<Incrementable>& y)
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{
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return !(x < y);
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}
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} // namespace boost
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#endif
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#endif // BOOST_HALF_OPEN_RANGE_HPP_
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