chain.hpp

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

// (C) Copyright Jonathan Turkanis 2003.
// 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.)

// See http://www.boost.org/libs/iostreams for documentation.

#ifndef BOOST_IOSTREAMS_DETAIL_CHAIN_HPP_INCLUDED
#define BOOST_IOSTREAMS_DETAIL_CHAIN_HPP_INCLUDED

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif

#include <algorithm>                            // for_each.
#include <cassert>
#include <exception>
#include <functional>                           // unary_function.
#include <iterator>                             // advance.
#include <list>
#include <memory>                               // allocator, auto_ptr.
#include <typeinfo>
#include <stdexcept>                            // logic_error, out_of_range.
#include <boost/checked_delete.hpp>
#include <boost/config.hpp>                     // BOOST_MSVC, template friends,
#include <boost/detail/workaround.hpp>          // BOOST_NESTED_TEMPLATE 
#include <boost/iostreams/constants.hpp>
#include <boost/iostreams/detail/access_control.hpp>
#include <boost/iostreams/detail/char_traits.hpp>
#include <boost/iostreams/detail/push.hpp>
#include <boost/iostreams/detail/streambuf.hpp> // pubsync.
#include <boost/iostreams/detail/wrap_unwrap.hpp>
#include <boost/iostreams/device/null.hpp>
#include <boost/iostreams/positioning.hpp>
#include <boost/iostreams/traits.hpp>           // is_filter.
#include <boost/iostreams/stream_buffer.hpp>
#include <boost/next_prior.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/static_assert.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type.hpp>
#if BOOST_WORKAROUND(BOOST_MSVC, < 1310)
# include <boost/mpl/int.hpp>
#endif

// Sometimes type_info objects must be compared by name. Borrowed from
// Boost.Python and Boost.Function.
#if (defined(__GNUC__) && __GNUC__ >= 3) || \
     defined(_AIX) || \
    (defined(__sgi) && defined(__host_mips)) || \
    (defined(linux) && defined(__INTEL_COMPILER) && defined(__ICC)) \
    /**/
# include <cstring>
# define BOOST_IOSTREAMS_COMPARE_TYPE_ID(X,Y) \
     (std::strcmp((X).name(),(Y).name()) == 0)
#else
# define BOOST_IOSTREAMS_COMPARE_TYPE_ID(X,Y) ((X)==(Y))
#endif

// Deprecated
#define BOOST_IOSTREAMS_COMPONENT_TYPE(chain, index) \
    chain.component_type( index ) \
    /**/

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1310)
# define BOOST_IOSTREAMS_COMPONENT(chain, index, target) \
    chain.component< target >( index ) \
    /**/
#else
# define BOOST_IOSTREAMS_COMPONENT(chain, index, target) \
    chain.component( index, ::boost::type< target >() ) \
    /**/
#endif

namespace boost { namespace iostreams {

//--------------Definition of chain and wchain--------------------------------//

namespace detail {

template<typename Chain> class chain_client;

//
// Concept name: Chain.
// Description: Represents a chain of stream buffers which provides access
//     to the first buffer in the chain and send notifications when the
//     streambufs are added to or removed from chain.
// Refines: Closable device with mode equal to typename Chain::mode.
// Models: chain, converting_chain.
// Example:
//
//    class chain {
//    public:
//        typedef xxx chain_type;
//        typedef xxx client_type;
//        typedef xxx mode;
//        bool is_complete() const;                  // Ready for i/o.
//        template<typename T>
//        void push( const T& t,                     // Adds a stream buffer to
//                   streamsize,                     // chain, based on t, with
//                   streamsize );                   // given buffer and putback
//                                                   // buffer sizes. Pass -1 to
//                                                   // request default size.
//    protected:
//        void register_client(client_type* client); // Associate client.
//        void notify();                             // Notify client.
//    };
//

//
// Description: Represents a chain of filters with an optional device at the
//      end.
// Template parameters:
//      Self - A class deriving from the current instantiation of this template.
//          This is an example of the Curiously Recurring Template Pattern.
//      Ch - The character type.
//      Tr - The character traits type.
//      Alloc - The allocator type.
//      Mode - A mode tag.
//
template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
class chain_base {
public:
    typedef Ch                                     char_type;
    BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr)
    typedef Alloc                                  allocator_type;
    typedef Mode                                   mode;
    struct category
        : Mode,
          device_tag
        { };
    typedef chain_client<Self>                     client_type;
    friend class chain_client<Self>;
private:
    typedef linked_streambuf<Ch>                   streambuf_type;
    typedef std::list<streambuf_type*>             list_type;
    typedef chain_base<Self, Ch, Tr, Alloc, Mode>  my_type;
protected:
    chain_base() : pimpl_(new chain_impl) { }
    chain_base(const chain_base& rhs): pimpl_(rhs.pimpl_) { }
public:

    //----------Buffer sizing-------------------------------------------------//

    // Sets the size of the buffer created for the devices to be added to this
    // chain. Does not affect the size of the buffer for devices already
    // added.
    void set_device_buffer_size(int n) { pimpl_->device_buffer_size_ = n; }

    // Sets the size of the buffer created for the filters to be added
    // to this chain. Does not affect the size of the buffer for filters already
    // added.
    void set_filter_buffer_size(int n) { pimpl_->filter_buffer_size_ = n; }

    // Sets the size of the putback buffer for filters and devices to be added
    // to this chain. Does not affect the size of the buffer for filters or
    // devices already added.
    void set_pback_size(int n) { pimpl_->pback_size_ = n; }

    //----------Device interface----------------------------------------------//

    std::streamsize read(char_type* s, std::streamsize n);
    std::streamsize write(const char_type* s, std::streamsize n);
    std::streampos seek(stream_offset off, BOOST_IOS::seekdir way);

    //----------Direct component access---------------------------------------//

    const std::type_info& component_type(int n) const
    {
        if (static_cast<size_type>(n) >= size())
            throw std::out_of_range("bad chain offset");
        return (*boost::next(list().begin(), n))->component_type();
    }

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

    template<typename T>
    T* component(int n) const { return component(n, boost::type<T>()); }

    // Deprecated.
    template<int N, typename T> 
    T* component() const { return component<T>(N); }
#endif

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1310)
    private:
#endif
    template<typename T>
    T* component(int n, boost::type<T>) const
    {
        if (static_cast<size_type>(n) >= size())
            throw std::out_of_range("bad chain offset");
        streambuf_type* link = *boost::next(list().begin(), n);
        if (BOOST_IOSTREAMS_COMPARE_TYPE_ID(link->component_type(), typeid(T)))
            return static_cast<T*>(link->component_impl());
        else
            return 0;
    }
public:

    //----------Container-like interface--------------------------------------//

    typedef typename list_type::size_type size_type;
    streambuf_type& front() { return *list().front(); }
    BOOST_IOSTREAMS_DEFINE_PUSH(push, mode, char_type, push_impl)
    void pop();
    bool empty() const { return list().empty(); }
    size_type size() const { return list().size(); }
    void reset();

    //----------Additional i/o functions--------------------------------------//

    // Returns true if this chain is non-empty and its final link
    // is a source or sink, i.e., if it is ready to perform i/o.
    bool is_complete() const;
    bool auto_close() const;
    void set_auto_close(bool close);
    bool sync() { return front().BOOST_IOSTREAMS_PUBSYNC() != -1; }
    bool strict_sync();
private:
    template<typename T>
    void push_impl(const T& t, int buffer_size = -1, int pback_size = -1)
    {
        typedef typename iostreams::category_of<T>::type  category;
        typedef typename unwrap_ios<T>::type              policy_type;
        typedef stream_buffer<
                    policy_type,
                    BOOST_IOSTREAMS_CHAR_TRAITS(char_type),
                    Alloc, Mode
                >                                         facade_type;
        BOOST_STATIC_ASSERT((is_convertible<category, Mode>::value));
        if (is_complete())
            throw std::logic_error("chain complete");
        streambuf_type* prev = !empty() ? list().back() : 0;
        buffer_size =
            buffer_size != -1 ?
                buffer_size :
                iostreams::optimal_buffer_size(t);
        pback_size =
            pback_size != -1 ?
                pback_size :
                pimpl_->pback_size_;
        std::auto_ptr<facade_type>
            buf(new facade_type(t, buffer_size, pback_size));
        list().push_back(buf.get());
        buf.release();
        if (is_device<policy_type>::value)
            pimpl_->flags_ |= f_complete | f_open;
        if (prev) prev->set_next(list().back());
        notify();
    }

    list_type& list() { return pimpl_->links_; }
    const list_type& list() const { return pimpl_->links_; }
    void register_client(client_type* client) { pimpl_->client_ = client; }
    void notify() { if (pimpl_->client_) pimpl_->client_->notify(); }

    //----------Nested classes------------------------------------------------//

    static void close(streambuf_type* b, BOOST_IOS::openmode m)
    {
        if (m & BOOST_IOS::out)
            b->BOOST_IOSTREAMS_PUBSYNC();
        b->close(m);
    }

    static void set_next(streambuf_type* b, streambuf_type* next)
    { b->set_next(next); }

    static void set_auto_close(streambuf_type* b, bool close)
    { b->set_auto_close(close); }

    struct closer  : public std::unary_function<streambuf_type*, void>  {
        closer(BOOST_IOS::openmode m) : mode_(m) { }
        void operator() (streambuf_type* b)
        {
            close(b, mode_);
        }
        BOOST_IOS::openmode mode_;
    };