Boost源码学习---scoped_array.hpp

scoped_array功能类似scoped_ptr，scoped_array管理的是new[]开辟的数组，其析构函数调用的是delete[]释放数组。

它没有重载解引用*和箭头操作符->，因为它不是普通指针，而是一个数组。它重载了[]，可以像使用数组下标那样访问数组。

#ifndef BOOST_SMART_PTR_SCOPED_ARRAY_HPP_INCLUDED#define BOOST_SMART_PTR_SCOPED_ARRAY_HPP_INCLUDED//  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.//  Copyright (c) 2001, 2002 Peter Dimov////  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)////  http://www.boost.org/libs/smart_ptr/scoped_array.htm//#include <boost/config.hpp>#include <boost/assert.hpp>#include <boost/checked_delete.hpp>#include <boost/smart_ptr/detail/sp_nullptr_t.hpp>#include <boost/detail/workaround.hpp>#include <cstddef>            // for std::ptrdiff_tnamespace boost{// Debug hooks#if defined(BOOST_SP_ENABLE_DEBUG_HOOKS)void sp_array_constructor_hook(void * p);void sp_array_destructor_hook(void * p);#endif//  scoped_array extends scoped_ptr to arrays. Deletion of the array pointed to//  is guaranteed, either on destruction of the scoped_array or via an explicit//  reset(). Use shared_array or std::vector if your needs are more complex.template<class T> class scoped_array // noncopyable{private:    T * px;    scoped_array(scoped_array const &);    scoped_array & operator=(scoped_array const &);    typedef scoped_array<T> this_type;    void operator==( scoped_array const& ) const;    void operator!=( scoped_array const& ) const;public:    typedef T element_type;    explicit scoped_array( T * p = 0 ) BOOST_NOEXCEPT : px( p )    {#if defined(BOOST_SP_ENABLE_DEBUG_HOOKS)        boost::sp_array_constructor_hook( px );#endif    }    ~scoped_array() // never throws    {#if defined(BOOST_SP_ENABLE_DEBUG_HOOKS)        boost::sp_array_destructor_hook( px );#endif        boost::checked_array_delete( px );    }    void reset(T * p = 0) // never throws (but has a BOOST_ASSERT in it, so not marked with BOOST_NOEXCEPT)    {        BOOST_ASSERT( p == 0 || p != px ); // catch self-reset errors        this_type(p).swap(*this);    }//重载[]，可以像访问数组一样访问其元素    T & operator[](std::ptrdiff_t i) const // never throws (but has a BOOST_ASSERT in it, so not marked with BOOST_NOEXCEPT)    {        BOOST_ASSERT( px != 0 );        BOOST_ASSERT( i >= 0 );        return px[i];    }    T * get() const BOOST_NOEXCEPT    {        return px;    }// implicit conversion to "bool"#include <boost/smart_ptr/detail/operator_bool.hpp>    void swap(scoped_array & b) BOOST_NOEXCEPT    {        T * tmp = b.px;        b.px = px;        px = tmp;    }};#if !defined( BOOST_NO_CXX11_NULLPTR )template<class T> inline bool operator==( scoped_array<T> const & p, boost::detail::sp_nullptr_t ) BOOST_NOEXCEPT{    return p.get() == 0;}template<class T> inline bool operator==( boost::detail::sp_nullptr_t, scoped_array<T> const & p ) BOOST_NOEXCEPT{    return p.get() == 0;}template<class T> inline bool operator!=( scoped_array<T> const & p, boost::detail::sp_nullptr_t ) BOOST_NOEXCEPT{    return p.get() != 0;}template<class T> inline bool operator!=( boost::detail::sp_nullptr_t, scoped_array<T> const & p ) BOOST_NOEXCEPT{    return p.get() != 0;}#endiftemplate<class T> inline void swap(scoped_array<T> & a, scoped_array<T> & b) BOOST_NOEXCEPT{    a.swap(b);}} // namespace boost#endif  // #ifndef BOOST_SMART_PTR_SCOPED_ARRAY_HPP_INCLUDED