// (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.

#ifndef BOOST_IOSTREAMS_READ_HPP_INCLUDED

#define BOOST_IOSTREAMS_READ_HPP_INCLUDED

#if defined(_MSC_VER) && (_MSC_VER >= 1020)

# pragma once

#endif

#include <boost/config.hpp>  // DEDUCED_TYPENAME, MSVC.

#include <boost/detail/workaround.hpp>

#include <boost/iostreams/char_traits.hpp>

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

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

#include <boost/iostreams/detail/ios.hpp>  // streamsize.

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

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

#include <boost/iostreams/operations_fwd.hpp>

#include <boost/mpl/if.hpp>

// Must come last.

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

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300) //-----------------------------------//

# include <boost/iostreams/detail/vc6/read.hpp>

#else // #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) //--------------------------//

namespace boost { namespace iostreams {

namespace detail {

template<typename T>

struct read_device_impl;

template<typename T>

struct read_filter_impl;

} // End namespace detail.

template<typename T>

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

{ return detail::read_device_impl<T>::get(detail::unwrap(t)); }

template<typename T>

inline std::streamsize

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

{ return detail::read_device_impl<T>::read(detail::unwrap(t), s, n); }

template<typename T, typename Source>

std::streamsize

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

{ return detail::read_filter_impl<T>::read(detail::unwrap(t), src, s, n); }

template<typename T>

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

{ return detail::read_device_impl<T>::putback(detail::unwrap(t), c); }

//----------------------------------------------------------------------------//

namespace detail {

// Helper function for adding -1 as EOF indicator.

inline std::streamsize check_eof(std::streamsize n) { return n != 0 ? n : -1; }

// Helper templates for reading from streambufs.

template<bool IsLinked>

struct true_eof_impl;

template<>

struct true_eof_impl<true> {

    template<typename T>

    static bool true_eof(T& t) { return t.true_eof(); }

};

template<>

struct true_eof_impl<false> {

    template<typename T>

    static bool true_eof(T& t) { return true; }

};

template<typename T>

inline bool true_eof(T& t)

{

    const bool linked = is_linked<T>::value;

    return true_eof_impl<linked>::true_eof(t);

}

//------------------Definition of read_device_impl----------------------------//

template<typename T>

struct read_device_impl

    : mpl::if_<

          detail::is_custom<T>,

          operations<T>,

          read_device_impl<

              BOOST_DEDUCED_TYPENAME

              detail::dispatch<

                  T, istream_tag, streambuf_tag, input

              >::type

          >

      >::type

    { };

template<>

struct read_device_impl<istream_tag> {

    template<typename T>

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

    { return t.get(); }

    template<typename T>

    static std::streamsize

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

    { return check_eof(t.rdbuf()->sgetn(s, n)); }

    template<typename T>

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

    {

        typedef typename char_type_of<T>::type          char_type;

        typedef BOOST_IOSTREAMS_CHAR_TRAITS(char_type)  traits_type;

        return !traits_type::eq_int_type( t.rdbuf()->sputbackc(c),

                                          traits_type::eof() );

    }

};

template<>

struct read_device_impl<streambuf_tag> {

    template<typename T>

    static typename int_type_of<T>::type

    get(T& t)

    {   // gcc 2.95 needs namespace qualification for char_traits.

        typedef typename char_type_of<T>::type     char_type;

        typedef iostreams::char_traits<char_type>  traits_type;

        typename int_type_of<T>::type c;

        return !traits_type::is_eof(c = t.sbumpc()) ||

                detail::true_eof(t)

                    ?

                c : traits_type::would_block();

    }

    template<typename T>

    static std::streamsize

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

    {

        std::streamsize amt;

        return (amt = t.sgetn(s, n)) != 0 ?

            amt :

            detail::true_eof(t) ?

                -1 :

                0;

    }

    template<typename T>

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

    {   // gcc 2.95 needs namespace qualification for char_traits.

        typedef typename char_type_of<T>::type     char_type;

        typedef iostreams::char_traits<char_type>  traits_type;

        return !traits_type::is_eof(t.sputbackc(c));

    }

};

template<>

struct read_device_impl<input> {

    template<typename T>

    static typename int_type_of<T>::type

    get(T& t)

    {   // gcc 2.95 needs namespace qualification for char_traits.

        typedef typename char_type_of<T>::type     char_type;

        typedef iostreams::char_traits<char_type>  traits_type;

        char_type c;

        std::streamsize amt;

        return (amt = t.read(&c, 1)) == 1 ?

            traits_type::to_int_type(c) :

            amt == -1 ?

                traits_type::eof() :

                traits_type::would_block();

    }

    template<typename T>

    static std::streamsize

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

    { return t.read(s, n); }

    template<typename T>

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

    {   // T must be Peekable.

        return t.putback(c);

    }

};

//------------------Definition of read_filter_impl----------------------------//

template<typename T>

struct read_filter_impl

    : mpl::if_<

          detail::is_custom<T>,

          operations<T>,

          read_filter_impl<

              BOOST_DEDUCED_TYPENAME

              detail::dispatch<

                  T, multichar_tag, any_tag

              >::type

          >

      >::type

    { };

template<>

struct read_filter_impl<multichar_tag> {

    template<typename T, typename Source>

    static std::streamsize read

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

    { return t.read(src, s, n); }

};

template<>

struct read_filter_impl<any_tag> {

    template<typename T, typename Source>

    static std::streamsize read

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

    {   // gcc 2.95 needs namespace qualification for char_traits.

        typedef typename char_type_of<T>::type     char_type;

        typedef iostreams::char_traits<char_type>  traits_type;

        for (std::streamsize off = 0; off < n; ++off) {

            typename traits_type::int_type c = t.get(src);

            if (traits_type::is_eof(c))

                return check_eof(off);

            if (traits_type::would_block(c))

                return off;

            s[off] = traits_type::to_char_type(c);

        }

        return n;

    }

};

} // End namespace detail.

} } // End namespaces iostreams, boost.

#endif // #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) //-------------------------//

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

#endif // #ifndef BOOST_IOSTREAMS_READ_HPP_INCLUDED