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