// (C) Copyright Jonathan Turkanis 2005.

// 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.

// Contains implementations of get, read, put, write and seek which

// check a device's mode at runtime instead of compile time.

#ifndef BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED

#define BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED

#include <boost/iostreams/categories.hpp>

#include <boost/iostreams/detail/dispatch.hpp>

#include <boost/iostreams/detail/error.hpp>

#include <boost/iostreams/get.hpp>

#include <boost/iostreams/put.hpp>

#include <boost/iostreams/read.hpp>

#include <boost/iostreams/seek.hpp>

#include <boost/iostreams/traits.hpp>

#include <boost/iostreams/write.hpp>

// Must come last.

#include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.

namespace boost { namespace iostreams {

namespace detail {

template<typename T> 

struct read_write_if_impl;

template<typename T> 

struct seek_if_impl;

} // End namespace detail.

template<typename T>

typename int_type_of<T>::type get_if(T& t)

{ 

    typedef typename detail::dispatch<T, input, output>::type tag;

    return detail::read_write_if_impl<tag>::get(t);

}

template<typename T>

inline std::streamsize

read_if(T& t, typename char_type_of<T>::type* s, std::streamsize n)

{ 

    typedef typename detail::dispatch<T, input, output>::type tag;

    return detail::read_write_if_impl<tag>::read(t, s, n);

}

template<typename T>

bool put_if(T& t, typename char_type_of<T>::type c)

{ 

    typedef typename detail::dispatch<T, output, input>::type tag;

    return detail::read_write_if_impl<tag>::put(t, c);

}

template<typename T>

inline std::streamsize write_if

    (T& t, const typename char_type_of<T>::type* s, std::streamsize n)

{ 

    typedef typename detail::dispatch<T, output, input>::type tag;

    return detail::read_write_if_impl<tag>::write(t, s, n);

}

template<typename T>

inline std::streampos

seek_if( T& t, stream_offset off, BOOST_IOS::seekdir way, 

         BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out )

{ 

    using namespace detail;

    typedef typename dispatch<T, random_access, any_tag>::type tag;

    return seek_if_impl<tag>::seek(t, off, way, which);

}

namespace detail {

//------------------Specializations of read_write_if_impl---------------------//

template<>

struct read_write_if_impl<input> {

    template<typename T>

    static typename int_type_of<T>::type get(T& t)

    { return iostreams::get(t); }

    template<typename T>

    static std::streamsize

    read(T& t, typename char_type_of<T>::type* s, std::streamsize n)

    { return iostreams::read(t, s, n); }

    template<typename T>

    static bool put(T&, typename char_type_of<T>::type)

    { throw cant_write(); }

    template<typename T>

    static std::streamsize 

    write(T&, const typename char_type_of<T>::type*, std::streamsize)

    { throw cant_write(); }

};

template<>

struct read_write_if_impl<output> {

    template<typename T>

    static typename int_type_of<T>::type get(T&)

    { throw cant_read(); }

    template<typename T>

    static std::streamsize

    read(T&, typename char_type_of<T>::type*, std::streamsize)

    { throw cant_read(); }

    template<typename T>

    static bool put(T& t, typename char_type_of<T>::type c)

    { return iostreams::put(t, c); }

    template<typename T>

    static std::streamsize 

    write( T& t, const typename char_type_of<T>::type* s, 

           std::streamsize n )

    { return iostreams::write(t, s, n); }

};

//------------------Specializations of seek_if_impl---------------------------//

template<>

struct seek_if_impl<random_access> {

    template<typename T>

    static stream_offset 

    seek( T& t, stream_offset off, BOOST_IOS::seekdir way, 

          BOOST_IOS::openmode which )

    { return iostreams::seek(t, off, way, which); }

};

template<>

struct seek_if_impl<any_tag> {

    template<typename T>

    static stream_offset 

    seek(T&, stream_offset, BOOST_IOS::seekdir, BOOST_IOS::openmode)

    { throw cant_seek(); }

};

} // End namespace detail.

} } // End namespaces iostreams, boost.

#include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.

#endif // #ifndef BOOST_IOSTREAMS_DETAIL_CHECKED_OPERATIONS_HPP_INCLUDED