boost/iostreams/detail/adapter/direct_adapter.hpp
// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
// (C) Copyright 2003-2007 Jonathan Turkanis
// 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_DETAIL_DIRECT_ADAPTER_HPP_INCLUDED
#define BOOST_IOSTREAMS_DETAIL_DIRECT_ADAPTER_HPP_INCLUDED
#if defined(_MSC_VER)
# pragma once
#endif
#include <boost/config.hpp> // SFINAE, MSVC, put ptrdiff_t in std.
#include <algorithm> // copy, min.
#include <cstddef> // ptrdiff_t.
#include <boost/detail/workaround.hpp>
#include <boost/iostreams/categories.hpp>
#include <boost/iostreams/detail/config/limits.hpp> // forwarding.
#include <boost/iostreams/detail/config/wide_streams.hpp> // locale.
#include <boost/iostreams/detail/double_object.hpp>
#include <boost/iostreams/detail/error.hpp>
#include <boost/iostreams/detail/ios.hpp> // openmode, seekdir, int types.
#include <boost/iostreams/traits.hpp> // mode_of, is_direct.
#include <boost/iostreams/operations.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/or.hpp>
#include <boost/preprocessor/iteration/local.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/static_assert.hpp>
#include <boost/throw_exception.hpp>
#include <boost/type_traits/is_convertible.hpp>
// Must come last.
#include <boost/iostreams/detail/config/disable_warnings.hpp> // VC7.1
namespace boost { namespace iostreams { namespace detail {
//------------------Definition of direct_adapter_base-------------------------//
// Put all initialization in base class to faciliate forwarding.
template<typename Direct>
class direct_adapter_base {
public:
typedef typename char_type_of<Direct>::type char_type;
typedef typename mode_of<Direct>::type mode_type;
struct category
: mode_type,
device_tag,
closable_tag
#ifndef BOOST_IOSTREAMS_NO_LOCALE
, localizable_tag
#endif
{ };
protected:
explicit direct_adapter_base(const Direct& d);
typedef is_convertible<category, two_sequence> is_double;
struct pointers {
pointers() : beg(0), ptr(0), end(0) { }
char_type *beg, *ptr, *end;
};
void init_input(mpl::true_);
void init_input(mpl::false_) { }
void init_output(mpl::true_);
void init_output(mpl::false_) { }
double_object<pointers, is_double> ptrs_;
Direct d_;
};
template<typename Direct>
class direct_adapter : private direct_adapter_base<Direct> {
private:
typedef direct_adapter_base<Direct> base_type;
typedef typename base_type::pointers pointers;
typedef typename base_type::is_double is_double;
using base_type::ptrs_;
using base_type::d_;
public:
typedef typename base_type::char_type char_type;
typedef typename base_type::category category;
// Constructors
#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1310)
direct_adapter(const Direct& d) : base_type(d) { }
direct_adapter(const direct_adapter& d) : base_type(d) { }
# define BOOST_PP_LOCAL_LIMITS (1, BOOST_IOSTREAMS_MAX_FORWARDING_ARITY)
#else
template<typename U>
struct is_direct
: mpl::or_<
is_same<U, direct_adapter<Direct> >,
is_same<U, Direct>
>
{ };
template<typename U>
direct_adapter(const U& u)
: base_type(forward(u, is_direct<U>()))
{ }
# define BOOST_PP_LOCAL_LIMITS (2, BOOST_IOSTREAMS_MAX_FORWARDING_ARITY)
#endif
#define BOOST_PP_LOCAL_MACRO(n) \
template<BOOST_PP_ENUM_PARAMS(n, typename P)> \
direct_adapter(BOOST_PP_ENUM_BINARY_PARAMS(n, const P, &p)) \
: base_type(Direct(BOOST_PP_ENUM_PARAMS(n, p))) \
{ } \
/**/
#include BOOST_PP_LOCAL_ITERATE()
#undef BOOST_PP_LOCAL_MACRO
// Device interface.
std::streamsize read(char_type* s, std::streamsize n);
std::streamsize write(const char_type* s, std::streamsize n);
std::streampos seek( stream_offset, BOOST_IOS::seekdir,
BOOST_IOS::openmode = BOOST_IOS::in | BOOST_IOS::out );
void close();
void close(BOOST_IOS::openmode which);
#ifndef BOOST_IOSTREAMS_NO_LOCALE
void imbue(const std::locale&);
#endif
// Direct device access.
Direct& operator*() { return d_; }
Direct* operator->() { return &d_; }
#if BOOST_WORKAROUND(BOOST_MSVC, <= 1310)
private:
template<typename U>
static Direct forward(const U& u, mpl::true_) { return u; }
template<typename U>
static Direct forward(const U& u, mpl::false_) { return Direct(u); }
#endif
};
//--------------Definition of wrap_direct and unwrap_direct-------------------//
template<typename Device>
struct wrap_direct_traits
: mpl::if_<
is_direct<Device>,
direct_adapter<Device>,
Device
>
{ };
template<typename Device>
typename wrap_direct_traits<Device>::type
inline wrap_direct(Device dev)
{
typedef typename wrap_direct_traits<Device>::type type;
return type(dev);
}
template<typename Device>
inline Device& unwrap_direct(Device& d) { return d; }
template<typename Device>
inline Device& unwrap_direct(direct_adapter<Device>& d) { return *d; }
//--------------Implementation of direct_adapter_base-------------------------//
template<typename Direct>
direct_adapter_base<Direct>::direct_adapter_base(const Direct& d) : d_(d)
{
init_input(is_convertible<category, input>());
init_output(is_convertible<category, output>());
}
template<typename Direct>
void direct_adapter_base<Direct>::init_input(mpl::true_)
{
std::pair<char_type*, char_type*> seq = iostreams::input_sequence(d_);
ptrs_.first().beg = seq.first;
ptrs_.first().ptr = seq.first;
ptrs_.first().end = seq.second;
}
template<typename Direct>
void direct_adapter_base<Direct>::init_output(mpl::true_)
{
std::pair<char_type*, char_type*> seq = iostreams::output_sequence(d_);
ptrs_.second().beg = seq.first;
ptrs_.second().ptr = seq.first;
ptrs_.second().end = seq.second;
}
//--------------Implementation of direct_adapter------------------------------//
template<typename Direct>
inline std::streamsize direct_adapter<Direct>::read
(char_type* s, std::streamsize n)
{
using namespace std;
pointers& get = ptrs_.first();
std::streamsize avail =
static_cast<std::streamsize>(get.end - get.ptr);
std::streamsize result = (std::min)(n, avail);
std::copy(get.ptr, get.ptr + result, s);
get.ptr += result;
return result != 0 ? result : -1;
}
template<typename Direct>
inline std::streamsize direct_adapter<Direct>::write
(const char_type* s, std::streamsize n)
{
using namespace std;
pointers& put = ptrs_.second();
if (n > static_cast<std::streamsize>(put.end - put.ptr))
boost::throw_exception(write_area_exhausted());
std::copy(s, s + n, put.ptr);
put.ptr += n;
return n;
}
template<typename Direct>
inline std::streampos direct_adapter<Direct>::seek
( stream_offset off, BOOST_IOS::seekdir way,
BOOST_IOS::openmode which )
{
using namespace std;
pointers& get = ptrs_.first();
pointers& put = ptrs_.second();
if (way == BOOST_IOS::cur && get.ptr != put.ptr)
boost::throw_exception(bad_seek());
ptrdiff_t next = 0;
if ((which & BOOST_IOS::in) || !is_double::value) {
if (way == BOOST_IOS::beg)
next = off;
else if (way == BOOST_IOS::cur)
next = get.ptr - get.beg + off;
else
next = get.end - get.beg + off;
if (next >= 0 && next <= get.end - get.beg)
get.ptr = get.beg + next;
else
boost::throw_exception(bad_seek());
}
if ((which & BOOST_IOS::out) && is_double::value) {
if (way == BOOST_IOS::beg)
next = off;
else if (way == BOOST_IOS::cur)
next = put.ptr - put.beg + off;
else
next = put.end - put.beg + off;
if (next >= 0 && next <= put.end - put.beg)
put.ptr = put.beg + next;
else
boost::throw_exception(bad_seek());
}
return offset_to_position(next);
}
template<typename Direct>
void direct_adapter<Direct>::close()
{
BOOST_STATIC_ASSERT((!is_convertible<category, two_sequence>::value));
detail::close_all(d_);
}
template<typename Direct>
void direct_adapter<Direct>::close(BOOST_IOS::openmode which)
{
BOOST_STATIC_ASSERT((is_convertible<category, two_sequence>::value));
boost::iostreams::close(d_, which);
}
#ifndef BOOST_IOSTREAMS_NO_LOCALE
template<typename Direct>
void direct_adapter<Direct>::imbue(const std::locale& loc)
{ boost::iostreams::imbue(d_, loc); }
#endif
} } } // End namespaces detail, iostreams, boost.
#include <boost/iostreams/detail/config/enable_warnings.hpp>
#endif // #ifndef BOOST_IOSTREAMS_DETAIL_DIRECT_ADAPTER_HPP_INCLUDED