chain.hpp

来自「support vector clustering for vc++」· HPP 代码 · 共 564 行 · 第 1/2 页

    friend struct closer;

    enum flags {
        f_complete = 1,
        f_open = 2,
        f_auto_close = 4
    };

    struct chain_impl {
        chain_impl()
            : client_(0), device_buffer_size_(default_device_buffer_size),
              filter_buffer_size_(default_filter_buffer_size),
              pback_size_(default_pback_buffer_size),
              flags_(f_auto_close)
            { }
        ~chain_impl() { try { close(); reset(); } catch (std::exception&) { } }
        void close()
            {
                if ((flags_ & f_open) != 0) {
                    stream_buffer< basic_null_device<Ch, Mode> > null;
                    if ((flags_ & f_complete) == 0) {
                        null.open(basic_null_device<Ch, Mode>());
                        set_next(links_.back(), &null);
                    }
                    links_.front()->BOOST_IOSTREAMS_PUBSYNC();
                    if (is_convertible<Mode, input>::value)
                        std::for_each( links_.rbegin(), links_.rend(),
                                       closer(BOOST_IOS::in) );
                    if (is_convertible<Mode, output>::value)
                        std::for_each( links_.begin(), links_.end(),
                                       closer(BOOST_IOS::out) );
                    flags_ &= ~f_open;
                }
            }
        void reset()
            {
                typedef typename list_type::iterator iterator;
                for ( iterator first = links_.begin(),
                               last = links_.end();
                      first != last;
                      ++first )
                {
                    if ( (flags_ & f_complete) == 0 ||
                         (flags_ & f_auto_close) == 0 )
                    {
                        set_auto_close(*first, false);
                    }
                    streambuf_type* buf = 0;
                    std::swap(buf, *first);
                    delete buf;
                }
                links_.clear();
                flags_ &= ~f_complete;
                flags_ &= ~f_open;
            }
        list_type     links_;
        client_type*  client_;
        int           device_buffer_size_,
                      filter_buffer_size_,
                      pback_size_;
        int           flags_;
    };
    friend struct chain_impl;

    //----------Member data---------------------------------------------------//

private:
    shared_ptr<chain_impl> pimpl_;
};

} // End namespace detail.

//
// Macro: BOOST_IOSTREAMS_DECL_CHAIN(name, category)
// Description: Defines a template derived from chain_base appropriate for a
//      particular i/o category. The template has the following parameters:
//      Ch - The character type.
//      Tr - The character traits type.
//      Alloc - The allocator type.
// Macro parameters:
//      name_ - The name of the template to be defined.
//      category_ - The i/o category of the template to be defined.
//
#define BOOST_IOSTREAMS_DECL_CHAIN(name_, default_char_) \
    template< typename Mode, typename Ch = default_char_, \
              typename Tr = BOOST_IOSTREAMS_CHAR_TRAITS(Ch), \
              typename Alloc = std::allocator<Ch> > \
    class name_ : public boost::iostreams::detail::chain_base< \
                            name_<Mode, Ch, Tr, Alloc>, \
                            Ch, Tr, Alloc, Mode \
                         > \
    { \
    public: \
        struct category : device_tag, Mode { }; \
        typedef Mode                                   mode; \
    private: \
        typedef boost::iostreams::detail::chain_base< \
                    name_<Mode, Ch, Tr, Alloc>, \
                    Ch, Tr, Alloc, Mode \
                >                                      base_type; \
    public: \
        typedef Ch                                     char_type; \
        typedef Tr                                     traits_type; \
        typedef typename traits_type::int_type         int_type; \
        typedef typename traits_type::off_type         off_type; \
        name_() { } \
        name_(const name_& rhs) { *this = rhs; } \
        name_& operator=(const name_& rhs) \
        { base_type::operator=(rhs); return *this; } \
    }; \
    /**/
BOOST_IOSTREAMS_DECL_CHAIN(chain, char)
BOOST_IOSTREAMS_DECL_CHAIN(wchain, wchar_t)
#undef BOOST_IOSTREAMS_DECL_CHAIN

//--------------Definition of chain_client------------------------------------//

namespace detail {

//
// Template name: chain_client
// Description: Class whose instances provide access to an underlying chain
//      using an interface similar to the chains.
// Subclasses: the various stream and stream buffer templates.
//
template<typename Chain>
class chain_client {
public:
    typedef Chain                             chain_type;
    typedef typename chain_type::char_type    char_type;
    typedef typename chain_type::traits_type  traits_type;
    typedef typename chain_type::size_type    size_type;
    typedef typename chain_type::mode         mode;

    chain_client(chain_type* chn = 0) : chain_(chn ) { }
    chain_client(chain_client* client) : chain_(client->chain_) { }
    virtual ~chain_client() { }

    const std::type_info& component_type(int n) const
    { return chain_->component_type(n); }

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1310)
    // Deprecated.
    template<int N>
    const std::type_info& component_type() const
    { return chain_->BOOST_NESTED_TEMPLATE component_type<N>(); }

    template<typename T>
    T* component(int n) const
    { return chain_->BOOST_NESTED_TEMPLATE component<T>(n); }

    // Deprecated.
    template<int N, typename T>
    T* component() const
    { return chain_->BOOST_NESTED_TEMPLATE component<N, T>(); }
#else
    template<typename T>
    T* component(int n, boost::type<T> t) const
    { return chain_->component(n, t); }
#endif

    bool is_complete() const { return chain_->is_complete(); }
    bool auto_close() const { return chain_->auto_close(); }
    void set_auto_close(bool close) { chain_->set_auto_close(close); }
    bool strict_sync() { return chain_->strict_sync(); }
    void set_device_buffer_size(std::streamsize n)
        { chain_->set_device_buffer_size(n); }
    void set_filter_buffer_size(std::streamsize n)
        { chain_->set_filter_buffer_size(n); }
    void set_pback_size(std::streamsize n) { chain_->set_pback_size(n); }
    BOOST_IOSTREAMS_DEFINE_PUSH(push, mode, char_type, push_impl)
    void pop() { chain_->pop(); }
    bool empty() const { return chain_->empty(); }
    size_type size() { return chain_->size(); }
    void reset() { chain_->reset(); }

    // Returns a copy of the underlying chain.
    chain_type filters() { return *chain_; }
    chain_type filters() const { return *chain_; }
protected:
    template<typename T>
    void push_impl(const T& t BOOST_IOSTREAMS_PUSH_PARAMS())
    { chain_->push(t BOOST_IOSTREAMS_PUSH_ARGS()); }
    chain_type& ref() { return *chain_; }
    void set_chain(chain_type* c)
    { chain_ = c; chain_->register_client(this); }
#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) && \
    (!BOOST_WORKAROUND(__BORLANDC__, < 0x600))
    template<typename S, typename C, typename T, typename A, typename M>
    friend class chain_base;
#else
    public:
#endif
    virtual void notify() { }
private:
    chain_type* chain_;
};

//--------------Implementation of chain_base----------------------------------//

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
inline std::streamsize chain_base<Self, Ch, Tr, Alloc, Mode>::read
    (char_type* s, std::streamsize n)
{ return iostreams::read(*list().front(), s, n); }

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
inline std::streamsize chain_base<Self, Ch, Tr, Alloc, Mode>::write
    (const char_type* s, std::streamsize n)
{ return iostreams::write(*list().front(), s, n); }

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
inline std::streampos chain_base<Self, Ch, Tr, Alloc, Mode>::seek
    (stream_offset off, BOOST_IOS::seekdir way)
{ return iostreams::seek(*list().front(), off, way); }

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
void chain_base<Self, Ch, Tr, Alloc, Mode>::reset()
{
    using namespace std;
    pimpl_->close();
    pimpl_->reset();
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
bool chain_base<Self, Ch, Tr, Alloc, Mode>::is_complete() const
{
    return (pimpl_->flags_ & f_complete) != 0;
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
bool chain_base<Self, Ch, Tr, Alloc, Mode>::auto_close() const
{
    return (pimpl_->flags_ & f_auto_close) != 0;
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
void chain_base<Self, Ch, Tr, Alloc, Mode>::set_auto_close(bool close)
{
    pimpl_->flags_ =
        (pimpl_->flags_ & ~f_auto_close) |
        (close ? f_auto_close : 0);
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
bool chain_base<Self, Ch, Tr, Alloc, Mode>::strict_sync()
{
    typedef typename list_type::iterator iterator;
    bool result = true;
    for ( iterator first = list().begin(),
                   last = list().end();
          first != last;
          ++first )
    {
        bool s = (*first)->strict_sync();
        result = result && s;
    }
    return result;
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
void chain_base<Self, Ch, Tr, Alloc, Mode>::pop()
{
    assert(!empty());
    if (auto_close())
        pimpl_->close();
    streambuf_type* buf = 0;
    std::swap(buf, list().back());
    buf->set_auto_close(false);
    buf->set_next(0);
    delete buf;
    list().pop_back();
    pimpl_->flags_ &= ~f_complete;
    if (auto_close() || list().empty())
        pimpl_->flags_ &= ~f_open;
}

} // End namespace detail.

} } // End namespaces iostreams, boost.

#endif // #ifndef BOOST_IOSTREAMS_DETAIL_CHAIN_HPP_INCLUDED