159 lines
4.9 KiB
C++
159 lines
4.9 KiB
C++
// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
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// (C) Copyright 2005-2007 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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// Contains implementations of get, read, put, write and seek which
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// check a device's mode at runtime instead of compile time.
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#ifndef BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED
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#define BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED
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#include <boost/iostreams/categories.hpp>
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#include <boost/iostreams/detail/dispatch.hpp>
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#include <boost/iostreams/detail/error.hpp>
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#include <boost/iostreams/detail/config/unreachable_return.hpp>
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#include <boost/iostreams/get.hpp>
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#include <boost/iostreams/put.hpp>
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#include <boost/iostreams/read.hpp>
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#include <boost/iostreams/seek.hpp>
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#include <boost/iostreams/traits.hpp>
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#include <boost/iostreams/write.hpp>
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#include <boost/throw_exception.hpp>
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// Must come last.
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#include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
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namespace boost { namespace iostreams {
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namespace detail {
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template<typename T>
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struct read_write_if_impl;
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template<typename T>
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struct seek_if_impl;
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} // End namespace detail.
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template<typename T>
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typename int_type_of<T>::type get_if(T& t)
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{
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typedef typename detail::dispatch<T, input, output>::type tag;
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return detail::read_write_if_impl<tag>::get(t);
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}
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template<typename T>
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inline std::streamsize
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read_if(T& t, typename char_type_of<T>::type* s, std::streamsize n)
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{
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typedef typename detail::dispatch<T, input, output>::type tag;
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return detail::read_write_if_impl<tag>::read(t, s, n);
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}
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template<typename T>
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bool put_if(T& t, typename char_type_of<T>::type c)
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{
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typedef typename detail::dispatch<T, output, input>::type tag;
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return detail::read_write_if_impl<tag>::put(t, c);
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}
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template<typename T>
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inline std::streamsize write_if
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(T& t, const typename char_type_of<T>::type* s, std::streamsize n)
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{
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typedef typename detail::dispatch<T, output, input>::type tag;
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return detail::read_write_if_impl<tag>::write(t, s, n);
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}
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template<typename T>
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inline std::streampos
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seek_if( T& t, stream_offset off, BOOST_IOS::seekdir way,
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BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out )
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{
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using namespace detail;
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typedef typename dispatch<T, random_access, any_tag>::type tag;
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return seek_if_impl<tag>::seek(t, off, way, which);
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}
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namespace detail {
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//------------------Specializations of read_write_if_impl---------------------//
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template<>
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struct read_write_if_impl<input> {
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template<typename T>
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static typename int_type_of<T>::type get(T& t)
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{ return iostreams::get(t); }
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template<typename T>
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static std::streamsize
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read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
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{ return iostreams::read(t, s, n); }
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template<typename T>
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static bool put(T&, typename char_type_of<T>::type)
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{ boost::throw_exception(cant_write());
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BOOST_IOSTREAMS_UNREACHABLE_RETURN(false) }
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template<typename T>
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static std::streamsize
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write(T&, const typename char_type_of<T>::type*, std::streamsize)
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{ boost::throw_exception(cant_write());
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BOOST_IOSTREAMS_UNREACHABLE_RETURN(0) }
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};
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template<>
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struct read_write_if_impl<output> {
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template<typename T>
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static typename int_type_of<T>::type get(T&)
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{ boost::throw_exception(cant_read());
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BOOST_IOSTREAMS_UNREACHABLE_RETURN(0) }
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template<typename T>
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static std::streamsize
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read(T&, typename char_type_of<T>::type*, std::streamsize)
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{ boost::throw_exception(cant_read());
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BOOST_IOSTREAMS_UNREACHABLE_RETURN(0) }
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template<typename T>
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static bool put(T& t, typename char_type_of<T>::type c)
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{ return iostreams::put(t, c); }
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template<typename T>
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static std::streamsize
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write( T& t, const typename char_type_of<T>::type* s,
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std::streamsize n )
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{ return iostreams::write(t, s, n); }
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};
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//------------------Specializations of seek_if_impl---------------------------//
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template<>
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struct seek_if_impl<random_access> {
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template<typename T>
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static std::streampos
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seek( T& t, stream_offset off, BOOST_IOS::seekdir way,
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BOOST_IOS::openmode which )
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{ return iostreams::seek(t, off, way, which); }
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};
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template<>
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struct seek_if_impl<any_tag> {
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template<typename T>
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static std::streampos
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seek(T&, stream_offset, BOOST_IOS::seekdir, BOOST_IOS::openmode)
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{ boost::throw_exception(cant_seek());
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BOOST_IOSTREAMS_UNREACHABLE_RETURN(std::streampos()) }
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};
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} // End namespace detail.
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} } // End namespaces iostreams, boost.
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#include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC.
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#endif // #ifndef BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED
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