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boost_iterator/include/boost/pending/iterator_adaptors.hpp
2000-09-18 08:24:47 +00:00

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// (C) Copyright David Abrahams 2000. Permission to copy, use,
// modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
//
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify,
// sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
#ifndef BOOST_ITERATOR_ADAPTOR_DWA053000_HPP_
#define BOOST_ITERATOR_ADAPTOR_DWA053000_HPP_
#include <iterator>
#include <boost/utility.hpp>
#include <boost/operators.hpp>
#include <boost/compressed_pair.hpp>
#ifdef BOOST_MSVC
#include <boost/int_iterator.hpp>
#endif
// I was having some problems with VC6. I couldn't tell whether our hack for
// stock GCC was causing problems so I needed an easy way to turn it on and
// off. Now we can test the hack with various compilers and still have an "out"
// if it doesn't work. -dwa 7/31/00
#if __GNUC__ == 2 && __GNUC_MINOR__ <= 96 && !defined(__STL_USE_NAMESPACES)
# define BOOST_RELOPS_AMBIGUITY_BUG 1
#endif
namespace boost {
#ifndef BOOST_MSVC
// Just a "type envelope"; works around some MSVC deficiencies.
template <class T>
struct type {};
//=============================================================================
// Default policies for iterator adaptors. You can use this as a base
// class if you want to customize particular policies.
struct default_iterator_policies
{
template <class Reference, class Iterator>
static Reference dereference(type<Reference>, const Iterator& x)
{ return *x; }
template <class Iterator>
static void increment(Iterator& x)
{ ++x; }
template <class Iterator>
static void decrement(Iterator& x)
{ --x; }
template <class Iterator, class DifferenceType>
static void advance(Iterator& x, DifferenceType n)
{ x += n; }
template <class Difference, class Iterator1, class Iterator2>
static Difference distance(type<Difference>, const Iterator1& x, const Iterator2& y)
{ return y - x; }
template <class Iterator1, class Iterator2>
static bool equal(const Iterator1& x, const Iterator2& y)
{ return x == y; }
template <class Iterator1, class Iterator2>
static bool less(const Iterator1& x, const Iterator2& y)
{ return x < y; }
};
// putting the comparisons in a base class avoids the g++
// ambiguous overload bug due to the relops operators
#ifdef BOOST_RELOPS_AMBIGUITY_BUG
template <class Derived, class Base>
struct iterator_comparisons : Base { };
template <class D1, class D2, class Base1, class Base2>
inline bool operator==(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().equal(x.iter(), y.iter());
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator!=(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return !x.policies().equal(x.iter(), y.iter());
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator<(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().less(x.iter(), y.iter());
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator>(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().less(y.iter(), x.iter());
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator>=(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return !x.policies().less(x.iter(), y.iter());
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator<=(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return !x.policies().less(y.iter(), x.iter());
}
#endif
//=============================================================================
// iterator_adaptor - A generalized adaptor around an existing
// iterator, which is itself an iterator
//
// Iterator - the iterator type being wrapped.
//
// Policies - a set of policies determining how the resulting iterator
// works.
//
// Traits - a class satisfying the same requirements as a specialization of
// std::iterator_traits for the resulting iterator.
//
// NonconstIterator - the corresponding non-const iterator type for
// Iterator, if any. You don't need to supply this if you are not make a
// const/non-const iterator pair.
//
template <class Iterator, class Policies,
#ifdef BOOST_NO_STD_ITERATOR_TRAITS
class Traits,
#else
class Traits = std::iterator_traits<Iterator>,
#endif
class NonconstIterator = Iterator
>
struct iterator_adaptor :
#ifdef BOOST_RELOPS_AMBIGUITY_BUG
iterator_comparisons<
iterator_adaptor<Iterator,Policies,Traits,NonconstIterator>,
#endif
boost::iterator<typename Traits::iterator_category,
typename Traits::value_type, typename Traits::difference_type,
typename Traits::pointer, typename Traits::reference>
#ifdef BOOST_RELOPS_AMBIGUITY_BUG
>
#endif
{
typedef iterator_adaptor<Iterator, Policies, Traits,NonconstIterator> Self;
public:
typedef typename Traits::difference_type difference_type;
typedef typename Traits::value_type value_type;
typedef typename Traits::pointer pointer;
typedef typename Traits::reference reference;
typedef typename Traits::iterator_category iterator_category;
iterator_adaptor() { }
iterator_adaptor(const Iterator& iter, const Policies& p = Policies())
: m_iter_p(iter, p) {}
#ifdef BOOST_MSVC6_MEMBER_TEMPLATES
template <class MutableIterator, class OtherTraits>
iterator_adaptor(const iterator_adaptor<MutableIterator, Policies, OtherTraits, NonconstIterator>& rhs)
: m_iter_p(rhs.iter(), rhs.policies()) {}
template <class MutableIterator, class OtherTraits>
Self& operator=(const iterator_adaptor<MutableIterator, Policies, OtherTraits, NonconstIterator>& rhs)
{
iter() = rhs.iter();
policies() = rhs.policies();
return *this;
}
#else
template <class OtherTraits>
iterator_adaptor(const iterator_adaptor<NonconstIterator, Policies, OtherTraits, NonconstIterator>& rhs)
: m_iter_p(rhs.iter(), rhs.policies()) {}
template <class OtherTraits>
Self& operator=(const iterator_adaptor<NonconstIterator, Policies, OtherTraits, NonconstIterator>& rhs)
{
iter() = rhs.iter();
policies() = rhs.policies();
return *this;
}
#endif
reference operator*() const {
return policies().dereference(type<reference>(), iter());
}
#ifdef _MSC_VER
# pragma warning(push)
# pragma warning( disable : 4284 )
#endif
pointer operator->() const
{ return &*this; }
#ifdef _MSC_VER
# pragma warning(pop)
#endif
reference operator[](difference_type n)
{ return *(*this + n); }
Self& operator++() {
policies().increment(iter());
return *this;
}
Self operator++(int) { Self tmp(*this); ++*this; return tmp; }
Self& operator--() {
policies().decrement(iter());
return *this;
}
Self operator--(int) { Self tmp(*this); --*this; return tmp; }
Self& operator+=(difference_type n) {
policies().advance(iter(), n);
return *this;
}
Self& operator-=(difference_type n) {
policies().advance(iter(), -n);
return *this;
}
private:
typedef Policies policies_type;
compressed_pair<Iterator,Policies> m_iter_p;
public: // too many compilers have trouble when these are private.
Policies& policies() { return m_iter_p.second(); }
const Policies& policies() const { return m_iter_p.second(); }
Iterator& iter() { return m_iter_p.first(); }
const Iterator& iter() const { return m_iter_p.first(); }
};
template <class Iterator, class Policies, class Traits, class NonconstIterator>
iterator_adaptor<Iterator,Policies,Traits,NonconstIterator>
operator-(iterator_adaptor<Iterator,Policies,Traits,NonconstIterator> p, const typename Traits::difference_type x)
{
return p -= x;
}
template <class Iterator, class Policies, class Traits, class NonconstIterator>
iterator_adaptor<Iterator,Policies,Traits,NonconstIterator>
operator+(iterator_adaptor<Iterator,Policies,Traits,NonconstIterator> p, const typename Traits::difference_type x)
{
return p += x;
}
template <class Iterator, class Policies, class Traits, class NonconstIterator>
iterator_adaptor<Iterator,Policies,Traits,NonconstIterator>
operator+(const typename Traits::difference_type x, iterator_adaptor<Iterator,Policies,Traits,NonconstIterator> p)
{
return p += x;
}
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
typename Traits1::difference_type operator-(
const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x,
const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y )
{
typedef typename Traits1::difference_type difference_type;
return x.policies().distance(type<difference_type>(), y.iter(), x.iter());
}
#ifndef BOOST_RELOPS_AMBIGUITY_BUG
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
inline bool
operator==(const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x, const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y) {
return x.policies().equal(x.iter(), y.iter());
}
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
inline bool
operator<(const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x, const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y) {
return x.policies().less(x.iter(), y.iter());
}
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
inline bool
operator>(const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x,
const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y) {
return x.policies().less(y.iter(), x.iter());
}
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
inline bool
operator>=(const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x, const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y) {
return !x.policies().less(x.iter(), y.iter());
}
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
inline bool
operator<=(const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x,
const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y) {
return !x.policies().less(y.iter(), x.iter());
}
template <class Iterator1, class Iterator2, class Policies, class Traits1, class Traits2, class NonconstIterator>
inline bool
operator!=(const iterator_adaptor<Iterator1,Policies,Traits1,NonconstIterator>& x,
const iterator_adaptor<Iterator2,Policies,Traits2,NonconstIterator>& y) {
return !x.policies().equal(x.iter(), y.iter());
}
#endif
//=============================================================================
// iterator_adaptors - A type generator that simplifies creating
// mutable/const pairs of iterator adaptors.
template <class Iterator, class ConstIterator,
#ifdef BOOST_NO_STD_ITERATOR_TRAITS
class Traits,
class ConstTraits,
#else
class Traits = std::iterator_traits<Iterator>,
class ConstTraits = std::iterator_traits<ConstIterator>,
#endif
class Policies = default_iterator_policies>
class iterator_adaptors
{
public:
typedef iterator_adaptor<Iterator, Policies, Traits, Iterator> iterator;
typedef iterator_adaptor<ConstIterator, Policies, ConstTraits, Iterator>
const_iterator;
};
//=============================================================================
// Transform Iterator Adaptor
template <class AdaptableUnaryFunction>
struct transform_iterator_policies : public default_iterator_policies
{
transform_iterator_policies() { }
transform_iterator_policies(const AdaptableUnaryFunction& f) : m_f(f) { }
template <class Reference, class Iterator>
Reference dereference(type<Reference>, const Iterator& x) const
{ return m_f(*x); }
AdaptableUnaryFunction m_f;
};
template <class AdaptableUnaryFunction, class IteratorTraits>
struct transform_iterator_traits {
typedef typename AdaptableUnaryFunction::result_type value_type;
typedef value_type reference;
typedef value_type* pointer;
typedef typename IteratorTraits::difference_type difference_type;
typedef typename IteratorTraits::iterator_category iterator_category;
};
template <class AdaptableUnaryFunction,
class Iterator,
#ifndef BOOST_NO_STD_ITERATOR_TRAITS
class Traits = std::iterator_traits<Iterator>
#else
class Traits
#endif
>
struct transform_iterator
{
typedef transform_iterator_traits<AdaptableUnaryFunction,Traits>
TransTraits;
typedef iterator_adaptor<Iterator,
transform_iterator_policies<AdaptableUnaryFunction>, TransTraits,
Iterator> type;
};
//=============================================================================
// Indirect Iterators Adaptor
// Tried implementing this with transform_iterator, but that required
// using boost::remove_ref, which is not compiler portable.
struct indirect_iterator_policies : public default_iterator_policies
{
template <class Reference, class Iterator>
Reference dereference(type<Reference>, const Iterator& x) const
{ return **x; }
};
template <class IndirectIterator,
#ifdef BOOST_NO_STD_ITERATOR_TRAITS
class IndirectTraits,
class Traits
#else
class IndirectTraits = std::iterator_traits<IndirectIterator>,
class Traits =
std::iterator_traits<typename IndirectTraits::value_type>
#endif
>
struct indirect_traits
{
typedef typename IndirectTraits::difference_type difference_type;
typedef typename Traits::value_type value_type;
typedef typename Traits::pointer pointer;
typedef typename Traits::reference reference;
typedef typename IndirectTraits::iterator_category iterator_category;
};
template <class IndirectIterator, class ConstIndirectIterator,
#ifdef BOOST_NO_STD_ITERATOR_TRAITS
class IndirectTraits,
class ConstIndirectTraits,
class Traits
#else
class IndirectTraits =
std::iterator_traits<IndirectIterator>,
class ConstIndirectTraits =
std::iterator_traits<ConstIndirectIterator>,
class Traits =
std::iterator_traits<typename IndirectTraits::value_type>
#endif
>
struct indirect_iterators
{
typedef typename IndirectTraits::value_type Iterator;
typedef typename Traits::value_type ValueType;
typedef iterator_adaptors<IndirectIterator, ConstIndirectIterator,
indirect_traits<IndirectIterator, IndirectTraits, Traits>,
indirect_traits<ConstIndirectIterator, ConstIndirectTraits, Traits>,
indirect_iterator_policies
> Adaptors;
typedef typename Adaptors::iterator iterator;
typedef typename Adaptors::const_iterator const_iterator;
};
//=============================================================================
// Reverse Iterators Adaptor
struct reverse_iterator_policies
{
template <class Reference, class Iterator>
Reference dereference(type<Reference>, const Iterator& x) const
{ return *boost::prior(x); }
template <class Iterator>
void increment(Iterator& x) const
{ --x; }
template <class Iterator>
void decrement(Iterator& x) const
{ ++x; }
template <class Iterator, class DifferenceType>
void advance(Iterator& x, DifferenceType n) const
{ x -= n; }
template <class Difference, class Iterator1, class Iterator2>
Difference distance(type<Difference>, const Iterator1& x,
const Iterator2& y) const
{ return x - y; }
template <class Iterator1, class Iterator2>
bool equal(const Iterator1& x, const Iterator2& y) const
{ return x == y; }
template <class Iterator1, class Iterator2>
bool less(const Iterator1& x, const Iterator2& y) const
{ return y < x; }
};
template <class Iterator, class ConstIterator,
#ifndef BOOST_NO_STD_ITERATOR_TRAITS
class Traits = std::iterator_traits<Iterator>,
class ConstTraits = std::iterator_traits<ConstIterator>
#else
class Traits,
class ConstTraits
#endif
>
struct reverse_iterators
{
typedef iterator_adaptors<Iterator,ConstIterator,Traits,ConstTraits,
reverse_iterator_policies> Adaptor;
typedef typename Adaptor::iterator iterator;
typedef typename Adaptor::const_iterator const_iterator;
};
//=============================================================================
// Counting Iterator and Integer Range Class
struct counting_iterator_policies : public default_iterator_policies
{
template <class IntegerType>
IntegerType dereference(type<IntegerType>, const IntegerType& i) const
{ return i; }
};
template <class IntegerType>
struct counting_iterator_traits {
typedef IntegerType value_type;
typedef IntegerType reference;
typedef value_type* pointer;
typedef std::ptrdiff_t difference_type;
typedef std::random_access_iterator_tag iterator_category;
};
#endif //#ifndef BOOST_MSVC
template <class IntegerType>
struct integer_range {
#ifdef BOOST_MSVC
typedef int_iterator<IntegerType> iterator;
#else
typedef iterator_adaptor<IntegerType, counting_iterator_policies,
counting_iterator_traits<IntegerType>, IntegerType> iterator;
#endif
typedef iterator const_iterator;
typedef IntegerType value_type;
typedef std::ptrdiff_t difference_type;
typedef IntegerType reference;
typedef IntegerType const_reference;
typedef const IntegerType* pointer;
typedef const IntegerType* const_pointer;
typedef IntegerType size_type;
integer_range(IntegerType start, IntegerType finish)
: m_start(start), m_finish(finish) { }
iterator begin() const { return iterator(m_start); }
iterator end() const { return iterator(m_finish); }
size_type size() const { return m_finish - m_start; }
bool empty() const { return m_finish == m_start; }
void swap(integer_range& x) {
std::swap(m_start, x.m_start);
std::swap(m_finish, x.m_finish);
}
protected:
IntegerType m_start, m_finish;
};
} // namespace boost
#endif