123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139 |
- // (C) Copyright Jeremy Siek 2001.
- // Distributed under 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)
- #ifndef BOOST_SHADOW_ITERATOR_HPP
- #define BOOST_SHADOW_ITERATOR_HPP
- #include <boost/iterator_adaptors.hpp>
- #include <boost/operators.hpp>
- namespace boost {
- namespace detail {
- template <class A, class B, class D>
- class shadow_proxy
- : boost::operators< shadow_proxy<A,B,D> >
- {
- typedef shadow_proxy self;
- public:
- inline shadow_proxy(A aa, B bb) : a(aa), b(bb) { }
- inline shadow_proxy(const self& x) : a(x.a), b(x.b) { }
- template <class Self>
- inline shadow_proxy(Self x) : a(x.a), b(x.b) { }
- inline self& operator=(const self& x) { a = x.a; b = x.b; return *this; }
- inline self& operator++() { ++a; return *this; }
- inline self& operator--() { --a; return *this; }
- inline self& operator+=(const self& x) { a += x.a; return *this; }
- inline self& operator-=(const self& x) { a -= x.a; return *this; }
- inline self& operator*=(const self& x) { a *= x.a; return *this; }
- inline self& operator/=(const self& x) { a /= x.a; return *this; }
- inline self& operator%=(const self& x) { return *this; } // JGS
- inline self& operator&=(const self& x) { return *this; } // JGS
- inline self& operator|=(const self& x) { return *this; } // JGS
- inline self& operator^=(const self& x) { return *this; } // JGS
- inline friend D operator-(const self& x, const self& y) {
- return x.a - y.a;
- }
- inline bool operator==(const self& x) const { return a == x.a; }
- inline bool operator<(const self& x) const { return a < x.a; }
- // protected:
- A a;
- B b;
- };
- struct shadow_iterator_policies
- {
- template <typename iter_pair>
- void initialize(const iter_pair&) { }
- template <typename Iter>
- typename Iter::reference dereference(const Iter& i) const {
- typedef typename Iter::reference R;
- return R(*i.base().first, *i.base().second);
- }
- template <typename Iter>
- bool equal(const Iter& p1, const Iter& p2) const {
- return p1.base().first == p2.base().first;
- }
- template <typename Iter>
- void increment(Iter& i) { ++i.base().first; ++i.base().second; }
- template <typename Iter>
- void decrement(Iter& i) { --i.base().first; --i.base().second; }
- template <typename Iter>
- bool less(const Iter& x, const Iter& y) const {
- return x.base().first < y.base().first;
- }
- template <typename Iter>
- typename Iter::difference_type
- distance(const Iter& x, const Iter& y) const {
- return y.base().first - x.base().first;
- }
- template <typename D, typename Iter>
- void advance(Iter& p, D n) { p.base().first += n; p.base().second += n; }
- };
- } // namespace detail
- template <typename IterA, typename IterB>
- struct shadow_iterator_generator {
-
- // To use the iterator_adaptor we can't derive from
- // random_access_iterator because we don't have a real reference.
- // However, we want the STL algorithms to treat the shadow
- // iterator like a random access iterator.
- struct shadow_iterator_tag : public std::input_iterator_tag {
- operator std::random_access_iterator_tag() {
- return std::random_access_iterator_tag();
- };
- };
- typedef typename std::iterator_traits<IterA>::value_type Aval;
- typedef typename std::iterator_traits<IterB>::value_type Bval;
- typedef typename std::iterator_traits<IterA>::reference Aref;
- typedef typename std::iterator_traits<IterB>::reference Bref;
- typedef typename std::iterator_traits<IterA>::difference_type D;
- typedef detail::shadow_proxy<Aval,Bval,Aval> V;
- typedef detail::shadow_proxy<Aref,Bref,Aval> R;
- typedef iterator_adaptor< std::pair<IterA, IterB>,
- detail::shadow_iterator_policies,
- V, R, V*, shadow_iterator_tag,
- D> type;
- };
- // short cut for creating a shadow iterator
- template <class IterA, class IterB>
- inline typename shadow_iterator_generator<IterA,IterB>::type
- make_shadow_iter(IterA a, IterB b) {
- typedef typename shadow_iterator_generator<IterA,IterB>::type Iter;
- return Iter(std::make_pair(a,b));
- }
- template <class Cmp>
- struct shadow_cmp {
- inline shadow_cmp(const Cmp& c) : cmp(c) { }
- template <class ShadowProxy1, class ShadowProxy2>
- inline bool operator()(const ShadowProxy1& x, const ShadowProxy2& y) const
- {
- return cmp(x.a, y.a);
- }
- Cmp cmp;
- };
- } // namespace boost
- namespace std {
- template <class A1, class B1, class D1,
- class A2, class B2, class D2>
- void swap(boost::detail::shadow_proxy<A1&,B1&,D1> x,
- boost::detail::shadow_proxy<A2&,B2&,D2> y)
- {
- std::swap(x.a, y.a);
- std::swap(x.b, y.b);
- }
- }
- #endif // BOOST_SHADOW_ITERATOR_HPP
|