Chris@16: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
Chris@16: // (C) Copyright 2003-2007 Jonathan Turkanis
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16: // See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16: // This material is heavily indebted to the discussion and code samples in
Chris@16: // A. Langer and K. Kreft, "Standard C++ IOStreams and Locales",
Chris@16: // Addison-Wesley, 2000, pp. 228-43.
Chris@16: 
Chris@16: // User "GMSB" provided an optimization for small seeks.
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_DETAIL_INDIRECT_STREAMBUF_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_DETAIL_INDIRECT_STREAMBUF_HPP_INCLUDED
Chris@16: 
Chris@16: #include <algorithm>                             // min, max.
Chris@16: #include <cassert>
Chris@16: #include <exception>
Chris@16: #include <typeinfo>
Chris@16: #include <boost/config.hpp>                      // Member template friends.
Chris@16: #include <boost/detail/workaround.hpp>
Chris@16: #include <boost/iostreams/constants.hpp>
Chris@16: #include <boost/iostreams/detail/adapter/concept_adapter.hpp>
Chris@16: #include <boost/iostreams/detail/buffer.hpp>
Chris@16: #include <boost/iostreams/detail/config/wide_streams.hpp>
Chris@16: #include <boost/iostreams/detail/double_object.hpp> 
Chris@16: #include <boost/iostreams/detail/execute.hpp>
Chris@16: #include <boost/iostreams/detail/functional.hpp>
Chris@16: #include <boost/iostreams/detail/ios.hpp>
Chris@16: #include <boost/iostreams/detail/optional.hpp>
Chris@16: #include <boost/iostreams/detail/push.hpp>
Chris@16: #include <boost/iostreams/detail/streambuf/linked_streambuf.hpp>
Chris@16: #include <boost/iostreams/operations.hpp>
Chris@16: #include <boost/iostreams/positioning.hpp>
Chris@16: #include <boost/iostreams/traits.hpp>
Chris@16: #include <boost/iostreams/operations.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/throw_exception.hpp>
Chris@16: #include <boost/type_traits/is_convertible.hpp>
Chris@16: 
Chris@16: // Must come last.
Chris@16: #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC, BCC 5.x
Chris@16: 
Chris@16: namespace boost { namespace iostreams { namespace detail {
Chris@16: 
Chris@16: //
Chris@16: // Description: The implementation of basic_streambuf used by chains.
Chris@16: //
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: class indirect_streambuf
Chris@16:     : public linked_streambuf<BOOST_DEDUCED_TYPENAME char_type_of<T>::type, Tr>
Chris@16: {
Chris@16: public:
Chris@16:     typedef typename char_type_of<T>::type                    char_type;
Chris@16:     BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr)
Chris@16: private:
Chris@16:     typedef typename category_of<T>::type                     category;
Chris@16:     typedef concept_adapter<T>                                wrapper;
Chris@16:     typedef detail::basic_buffer<char_type, Alloc>            buffer_type;
Chris@16:     typedef indirect_streambuf<T, Tr, Alloc, Mode>            my_type;
Chris@16:     typedef detail::linked_streambuf<char_type, traits_type>  base_type;
Chris@16:     typedef linked_streambuf<char_type, Tr>                   streambuf_type;
Chris@16: public:
Chris@16:     indirect_streambuf();
Chris@16: 
Chris@16:     void open(const T& t BOOST_IOSTREAMS_PUSH_PARAMS());
Chris@16:     bool is_open() const;
Chris@16:     void close();
Chris@16:     bool auto_close() const;
Chris@16:     void set_auto_close(bool close);
Chris@16:     bool strict_sync();
Chris@16: 
Chris@16:     // Declared in linked_streambuf.
Chris@16:     T* component() { return &*obj(); }
Chris@16: protected:
Chris@16: #if !BOOST_WORKAROUND(__GNUC__, == 2)
Chris@16:     BOOST_IOSTREAMS_USING_PROTECTED_STREAMBUF_MEMBERS(base_type)
Chris@16: #endif
Chris@16: 
Chris@16:     //----------virtual functions---------------------------------------------//
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_NO_LOCALE
Chris@16:     void imbue(const std::locale& loc);
Chris@16: #endif
Chris@16: #ifdef BOOST_IOSTREAMS_NO_STREAM_TEMPLATES
Chris@16:     public:
Chris@16: #endif
Chris@16:     int_type underflow();
Chris@16:     int_type pbackfail(int_type c);
Chris@16:     int_type overflow(int_type c);
Chris@16:     int sync();
Chris@16:     pos_type seekoff( off_type off, BOOST_IOS::seekdir way,
Chris@16:                       BOOST_IOS::openmode which );
Chris@16:     pos_type seekpos(pos_type sp, BOOST_IOS::openmode which);
Chris@16: 
Chris@16:     // Declared in linked_streambuf.
Chris@16:     void set_next(streambuf_type* next);
Chris@16:     void close_impl(BOOST_IOS::openmode m);
Chris@16:     const std::type_info& component_type() const { return typeid(T); }
Chris@16:     void* component_impl() { return component(); }
Chris@16: private:
Chris@16: 
Chris@16:     //----------Accessor functions--------------------------------------------//
Chris@16: 
Chris@16:     wrapper& obj() { return *storage_; }
Chris@16:     streambuf_type* next() const { return next_; }
Chris@16:     buffer_type& in() { return buffer_.first(); }
Chris@16:     buffer_type& out() { return buffer_.second(); }
Chris@16:     bool can_read() const { return is_convertible<Mode, input>::value; }
Chris@16:     bool can_write() const { return is_convertible<Mode, output>::value; }
Chris@16:     bool output_buffered() const { return (flags_ & f_output_buffered) != 0; }
Chris@16:     bool shared_buffer() const { return is_convertible<Mode, seekable>::value; }
Chris@16:     void set_flags(int f) { flags_ = f; }
Chris@16: 
Chris@16:     //----------State changing functions--------------------------------------//
Chris@16: 
Chris@16:     virtual void init_get_area();
Chris@16:     virtual void init_put_area();
Chris@16: 
Chris@16:     //----------Utility function----------------------------------------------//
Chris@16: 
Chris@16:     pos_type seek_impl( stream_offset off, BOOST_IOS::seekdir way,
Chris@16:                         BOOST_IOS::openmode which );
Chris@16:     void sync_impl();
Chris@16: 
Chris@16:     enum flag_type {
Chris@16:         f_open             = 1,
Chris@16:         f_output_buffered  = f_open << 1,
Chris@16:         f_auto_close       = f_output_buffered << 1
Chris@16:     };
Chris@16: 
Chris@16:     optional<wrapper>           storage_;
Chris@16:     streambuf_type*             next_;
Chris@16:     double_object<
Chris@16:         buffer_type,
Chris@16:         is_convertible<
Chris@16:             Mode,
Chris@16:             two_sequence
Chris@16:         >
Chris@16:     >                           buffer_;
Chris@16:     std::streamsize             pback_size_;
Chris@16:     int                         flags_;
Chris@16: };
Chris@16: 
Chris@16: //--------------Implementation of indirect_streambuf--------------------------//
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::indirect_streambuf()
Chris@16:     : next_(0), pback_size_(0), flags_(f_auto_close) { }
Chris@16: 
Chris@16: //--------------Implementation of open, is_open and close---------------------//
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::open
Chris@16:     (const T& t, std::streamsize buffer_size, std::streamsize pback_size)
Chris@16: {
Chris@16:     using namespace std;
Chris@16: 
Chris@16:     // Normalize buffer sizes.
Chris@16:     buffer_size =
Chris@16:         (buffer_size != -1) ?
Chris@16:         buffer_size :
Chris@16:         iostreams::optimal_buffer_size(t);
Chris@16:     pback_size =
Chris@16:         (pback_size != -1) ?
Chris@16:         pback_size :
Chris@16:         default_pback_buffer_size;
Chris@16: 
Chris@16:     // Construct input buffer.
Chris@16:     if (can_read()) {
Chris@16:         pback_size_ = (std::max)(std::streamsize(2), pback_size); // STLPort needs 2.
Chris@16:         std::streamsize size =
Chris@16:             pback_size_ +
Chris@16:             ( buffer_size ? buffer_size: 1 );
Chris@16:         in().resize(size);
Chris@16:         if (!shared_buffer())
Chris@16:             init_get_area();
Chris@16:     }
Chris@16: 
Chris@16:     // Construct output buffer.
Chris@16:     if (can_write() && !shared_buffer()) {
Chris@16:         if (buffer_size != 0)
Chris@16:             out().resize(buffer_size);
Chris@16:         init_put_area();
Chris@16:     }
Chris@16: 
Chris@16:     storage_.reset(wrapper(t));
Chris@16:     flags_ |= f_open;
Chris@16:     if (can_write() && buffer_size > 1)
Chris@16:         flags_ |= f_output_buffered;
Chris@16:     this->set_true_eof(false);
Chris@16:     this->set_needs_close();
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: inline bool indirect_streambuf<T, Tr, Alloc, Mode>::is_open() const
Chris@16: { return (flags_ & f_open) != 0; }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::close()
Chris@16: {
Chris@16:     using namespace std;
Chris@16:     base_type* self = this;
Chris@16:     detail::execute_all(
Chris@16:         detail::call_member_close(*self, BOOST_IOS::in),
Chris@16:         detail::call_member_close(*self, BOOST_IOS::out),
Chris@16:         detail::call_reset(storage_),
Chris@16:         detail::clear_flags(flags_)
Chris@16:     );
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: bool indirect_streambuf<T, Tr, Alloc, Mode>::auto_close() const
Chris@16: { return (flags_ & f_auto_close) != 0; }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::set_auto_close(bool close)
Chris@16: { flags_ = (flags_ & ~f_auto_close) | (close ? f_auto_close : 0); }
Chris@16: 
Chris@16: //--------------Implementation virtual functions------------------------------//
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_NO_LOCALE
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::imbue(const std::locale& loc)
Chris@16: {
Chris@16:     if (is_open()) {
Chris@16:         obj().imbue(loc);
Chris@16:         if (next_)
Chris@16:             next_->pubimbue(loc);
Chris@16:     }
Chris@16: }
Chris@16: #endif
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: typename indirect_streambuf<T, Tr, Alloc, Mode>::int_type
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::underflow()
Chris@16: {
Chris@16:     using namespace std;
Chris@16:     if (!gptr()) init_get_area();
Chris@16:     buffer_type& buf = in();
Chris@16:     if (gptr() < egptr()) return traits_type::to_int_type(*gptr());
Chris@16: 
Chris@16:     // Fill putback buffer.
Chris@16:     std::streamsize keep = 
Chris@16:         (std::min)( static_cast<std::streamsize>(gptr() - eback()),
Chris@16:                     pback_size_ );
Chris@16:     if (keep)
Chris@16:         traits_type::move( buf.data() + (pback_size_ - keep),
Chris@16:                            gptr() - keep, keep );
Chris@16: 
Chris@16:     // Set pointers to reasonable values in case read throws.
Chris@16:     setg( buf.data() + pback_size_ - keep,
Chris@16:           buf.data() + pback_size_,
Chris@16:           buf.data() + pback_size_ );
Chris@16: 
Chris@16:     // Read from source.
Chris@16:     std::streamsize chars =
Chris@16:         obj().read(buf.data() + pback_size_, buf.size() - pback_size_, next_);
Chris@16:     if (chars == -1) {
Chris@16:         this->set_true_eof(true);
Chris@16:         chars = 0;
Chris@16:     }
Chris@16:     setg(eback(), gptr(), buf.data() + pback_size_ + chars);
Chris@16:     return chars != 0 ?
Chris@16:         traits_type::to_int_type(*gptr()) :
Chris@16:         traits_type::eof();
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: typename indirect_streambuf<T, Tr, Alloc, Mode>::int_type
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::pbackfail(int_type c)
Chris@16: {
Chris@16:     if (gptr() != eback()) {
Chris@16:         gbump(-1);
Chris@16:         if (!traits_type::eq_int_type(c, traits_type::eof()))
Chris@16:             *gptr() = traits_type::to_char_type(c);
Chris@16:         return traits_type::not_eof(c);
Chris@16:     } else {
Chris@16:         boost::throw_exception(bad_putback());
Chris@16:     }
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: typename indirect_streambuf<T, Tr, Alloc, Mode>::int_type
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::overflow(int_type c)
Chris@16: {
Chris@16:     if ( (output_buffered() && pptr() == 0) ||
Chris@16:          (shared_buffer() && gptr() != 0) )
Chris@16:     {
Chris@16:         init_put_area();
Chris@16:     }
Chris@16:     if (!traits_type::eq_int_type(c, traits_type::eof())) {
Chris@16:         if (output_buffered()) {
Chris@16:             if (pptr() == epptr()) {
Chris@16:                 sync_impl();
Chris@16:                 if (pptr() == epptr())
Chris@16:                     return traits_type::eof();
Chris@16:             }
Chris@16:             *pptr() = traits_type::to_char_type(c);
Chris@16:             pbump(1);
Chris@16:         } else {
Chris@16:             char_type d = traits_type::to_char_type(c);
Chris@16:             if (obj().write(&d, 1, next_) != 1)
Chris@16:                 return traits_type::eof();
Chris@16:         }
Chris@16:     }
Chris@16:     return traits_type::not_eof(c);
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: int indirect_streambuf<T, Tr, Alloc, Mode>::sync()
Chris@16: {
Chris@16:     try { // sync() is no-throw.
Chris@16:         sync_impl();
Chris@16:         obj().flush(next_);
Chris@16:         return 0;
Chris@16:     } catch (...) { return -1; }
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: bool indirect_streambuf<T, Tr, Alloc, Mode>::strict_sync()
Chris@16: {
Chris@16:     try { // sync() is no-throw.
Chris@16:         sync_impl();
Chris@16:         return obj().flush(next_);
Chris@16:     } catch (...) { return false; }
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: inline typename indirect_streambuf<T, Tr, Alloc, Mode>::pos_type
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::seekoff
Chris@16:     (off_type off, BOOST_IOS::seekdir way, BOOST_IOS::openmode which)
Chris@16: { return seek_impl(off, way, which); }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: inline typename indirect_streambuf<T, Tr, Alloc, Mode>::pos_type
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::seekpos
Chris@16:     (pos_type sp, BOOST_IOS::openmode which)
Chris@16: { 
Chris@16:     return seek_impl(position_to_offset(sp), BOOST_IOS::beg, which); 
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: typename indirect_streambuf<T, Tr, Alloc, Mode>::pos_type
Chris@16: indirect_streambuf<T, Tr, Alloc, Mode>::seek_impl
Chris@16:     (stream_offset off, BOOST_IOS::seekdir way, BOOST_IOS::openmode which)
Chris@16: {
Chris@16:     if ( gptr() != 0 && way == BOOST_IOS::cur && which == BOOST_IOS::in && 
Chris@16:          eback() - gptr() <= off && off <= egptr() - gptr() ) 
Chris@16:     {   // Small seek optimization
Chris@16:         gbump(off);
Chris@16:         return obj().seek(0, BOOST_IOS::cur, BOOST_IOS::in, next_) -
Chris@16:                static_cast<off_type>(egptr() - gptr());
Chris@16:     }
Chris@16:     if (pptr() != 0) 
Chris@16:         this->BOOST_IOSTREAMS_PUBSYNC(); // sync() confuses VisualAge 6.
Chris@16:     if (way == BOOST_IOS::cur && gptr())
Chris@16:         off -= static_cast<off_type>(egptr() - gptr());
Chris@16:     setg(0, 0, 0);
Chris@16:     setp(0, 0);
Chris@16:     return obj().seek(off, way, which, next_);
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: inline void indirect_streambuf<T, Tr, Alloc, Mode>::set_next
Chris@16:     (streambuf_type* next)
Chris@16: { next_ = next; }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: inline void indirect_streambuf<T, Tr, Alloc, Mode>::close_impl
Chris@16:     (BOOST_IOS::openmode which)
Chris@16: {
Chris@16:     if (which == BOOST_IOS::in && is_convertible<Mode, input>::value) {
Chris@16:         setg(0, 0, 0);
Chris@16:     }
Chris@16:     if (which == BOOST_IOS::out && is_convertible<Mode, output>::value) {
Chris@16:         sync();
Chris@16:         setp(0, 0);
Chris@16:     }
Chris@16:     if ( !is_convertible<category, dual_use>::value ||
Chris@16:          is_convertible<Mode, input>::value == (which == BOOST_IOS::in) )
Chris@16:     {
Chris@16:         obj().close(which, next_);
Chris@16:     }
Chris@16: }
Chris@16: 
Chris@16: //----------State changing functions------------------------------------------//
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::sync_impl()
Chris@16: {
Chris@16:     std::streamsize avail, amt;
Chris@16:     if ((avail = static_cast<std::streamsize>(pptr() - pbase())) > 0) {
Chris@16:         if ((amt = obj().write(pbase(), avail, next())) == avail)
Chris@16:             setp(out().begin(), out().end());
Chris@16:         else {
Chris@16:             const char_type* ptr = pptr();
Chris@16:             setp(out().begin() + amt, out().end());
Chris@16:             pbump(ptr - pptr());
Chris@16:         }
Chris@16:     }
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::init_get_area()
Chris@16: {
Chris@16:     if (shared_buffer() && pptr() != 0) {
Chris@16:         sync_impl();
Chris@16:         setp(0, 0);
Chris@16:     }
Chris@16:     setg(in().begin(), in().begin(), in().begin());
Chris@16: }
Chris@16: 
Chris@16: template<typename T, typename Tr, typename Alloc, typename Mode>
Chris@16: void indirect_streambuf<T, Tr, Alloc, Mode>::init_put_area()
Chris@16: {
Chris@16:     using namespace std;
Chris@16:     if (shared_buffer() && gptr() != 0)
Chris@16:         setg(0, 0, 0);
Chris@16:     if (output_buffered())
Chris@16:         setp(out().begin(), out().end());
Chris@16:     else
Chris@16:         setp(0, 0);
Chris@16: }
Chris@16: 
Chris@16: //----------------------------------------------------------------------------//
Chris@16: 
Chris@16: } } } // End namespaces detail, iostreams, boost.
Chris@16: 
Chris@16: #include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC, BCC 5.x
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_DETAIL_INDIRECT_STREAMBUF_HPP_INCLUDED