is_lvalue_iterator.cpp

来自「Boost provides free peer-reviewed portab」· C++ 代码 · 共 146 行

// Copyright David Abrahams 2003. 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)

#include <deque>
#include <iterator>
#include <iostream>
#include <boost/static_assert.hpp>
#include <boost/noncopyable.hpp>
#include <boost/type_traits/broken_compiler_spec.hpp>
#include <boost/iterator/is_lvalue_iterator.hpp>
#include <boost/iterator.hpp>

// Last, for BOOST_NO_LVALUE_RETURN_DETECTION
#include <boost/iterator/detail/config_def.hpp>

struct v
{
    v();
    ~v();
};

BOOST_TT_BROKEN_COMPILER_SPEC(v)

struct value_iterator : boost::iterator<std::input_iterator_tag,v>
{
    v operator*() const;
};

struct noncopyable_iterator : boost::iterator<std::forward_iterator_tag,boost::noncopyable>
{
    boost::noncopyable const& operator*() const;
};

template <class T>
struct proxy_iterator
  : boost::iterator<std::output_iterator_tag,T>
{
    typedef T value_type;
    
#if BOOST_WORKAROUND(__GNUC__, == 2)
    typedef boost::iterator<std::input_iterator_tag,value_type> base;
    typedef base::iterator_category iterator_category;
    typedef base::difference_type difference_type;
    typedef base::pointer pointer;
    typedef base::reference reference;
#endif 
    
    struct proxy
    {
        operator value_type&() const;
        proxy& operator=(value_type) const;
    };
        
    proxy operator*() const;
};

template <class T>
struct lvalue_iterator
{
    typedef T value_type;
    typedef T& reference;
    typedef T difference_type;
    typedef std::input_iterator_tag iterator_category;
    typedef T* pointer;

    T& operator*() const;
    lvalue_iterator& operator++();
    lvalue_iterator operator++(int);
};

template <class T>
struct constant_lvalue_iterator
{
    typedef T value_type;
    typedef T const& reference;
    typedef T difference_type;
    typedef std::input_iterator_tag iterator_category;
    typedef T const* pointer;

    T const& operator*() const;
    constant_lvalue_iterator& operator++();
    constant_lvalue_iterator operator++(int);
};

BOOST_TT_BROKEN_COMPILER_SPEC(proxy_iterator<v>::proxy)
BOOST_TT_BROKEN_COMPILER_SPEC(proxy_iterator<int>::proxy)

int main()
{
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<v*>::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<v const*>::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<std::deque<v>::iterator>::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<std::deque<v>::const_iterator>::value);
    BOOST_STATIC_ASSERT(!boost::is_lvalue_iterator<std::back_insert_iterator<std::deque<v> > >::value);
    BOOST_STATIC_ASSERT(!boost::is_lvalue_iterator<std::ostream_iterator<v> >::value);
    BOOST_STATIC_ASSERT(!boost::is_lvalue_iterator<proxy_iterator<v> >::value);
    BOOST_STATIC_ASSERT(!boost::is_lvalue_iterator<proxy_iterator<int> >::value);
#ifndef BOOST_NO_LVALUE_RETURN_DETECTION
    BOOST_STATIC_ASSERT(!boost::is_lvalue_iterator<value_iterator>::value);
#endif
    // Make sure inaccessible copy constructor doesn't prevent
    // reference binding
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<noncopyable_iterator>::value);

    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<lvalue_iterator<v> >::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<lvalue_iterator<int> >::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<lvalue_iterator<char*> >::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<lvalue_iterator<float> >::value);

    
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<constant_lvalue_iterator<v> >::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<constant_lvalue_iterator<int> >::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<constant_lvalue_iterator<char*> >::value);
    BOOST_STATIC_ASSERT(boost::is_lvalue_iterator<constant_lvalue_iterator<float> >::value);

    
    
    BOOST_STATIC_ASSERT(boost::is_non_const_lvalue_iterator<v*>::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<v const*>::value);
    BOOST_STATIC_ASSERT(boost::is_non_const_lvalue_iterator<std::deque<v>::iterator>::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<std::deque<v>::const_iterator>::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<std::back_insert_iterator<std::deque<v> > >::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<std::ostream_iterator<v> >::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<proxy_iterator<v> >::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<proxy_iterator<int> >::value);
#ifndef BOOST_NO_LVALUE_RETURN_DETECTION
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<value_iterator>::value);
#endif
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<noncopyable_iterator>::value);
    
    BOOST_STATIC_ASSERT(boost::is_non_const_lvalue_iterator<lvalue_iterator<v> >::value);
#if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
    BOOST_STATIC_ASSERT(boost::is_non_const_lvalue_iterator<lvalue_iterator<int> >::value);
#endif 
    BOOST_STATIC_ASSERT(boost::is_non_const_lvalue_iterator<lvalue_iterator<char*> >::value);
    BOOST_STATIC_ASSERT(boost::is_non_const_lvalue_iterator<lvalue_iterator<float> >::value);
    
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<constant_lvalue_iterator<v> >::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<constant_lvalue_iterator<int> >::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<constant_lvalue_iterator<char*> >::value);
    BOOST_STATIC_ASSERT(!boost::is_non_const_lvalue_iterator<constant_lvalue_iterator<float> >::value);
    
    return 0;
}