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// (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_RANGE_ADAPTER_HPP_INCLUDED
#define BOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
#include <algorithm> // min.
#include <boost/assert.hpp>
#include <cstddef> // ptrdiff_t.
#include <iosfwd> // streamsize, streamoff.
#include <boost/detail/iterator.hpp> // boost::iterator_traits.
#include <boost/iostreams/categories.hpp>
#include <boost/iostreams/detail/error.hpp>
#include <boost/iostreams/positioning.hpp>
#include <boost/mpl/if.hpp>
#include <boost/throw_exception.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/utility/enable_if.hpp>
// Must come last.
#include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
namespace boost { namespace iostreams { namespace detail {
// Used for simulated tag dispatch.
template<typename Traversal> struct range_adapter_impl;
//
// Template name: range_adapter
// Description: Device based on an instance of boost::iterator_range.
// Template paramters:
// Mode - A mode tag.
// Range - An instance of iterator_range.
//
template<typename Mode, typename Range>
class range_adapter {
private:
typedef typename Range::iterator iterator;
typedef boost::detail::iterator_traits<iterator> iter_traits;
typedef typename iter_traits::iterator_category iter_cat;
public:
typedef typename Range::value_type char_type;
struct category : Mode, device_tag { };
typedef typename
mpl::if_<
is_convertible<
iter_cat,
std::random_access_iterator_tag
>,
std::random_access_iterator_tag,
std::forward_iterator_tag
>::type tag;
typedef range_adapter_impl<tag> impl;
explicit range_adapter(const Range& rng);
range_adapter(iterator first, iterator last);
std::streamsize read(char_type* s, std::streamsize n);
std::streamsize write(const char_type* s, std::streamsize n);
std::streampos seek(stream_offset off, BOOST_IOS::seekdir way);
private:
iterator first_, cur_, last_;
};
//------------------Implementation of range_adapter---------------------------//
template<typename Mode, typename Range>
range_adapter<Mode, Range>::range_adapter(const Range& rng)
: first_(rng.begin()), cur_(rng.begin()), last_(rng.end()) { }
template<typename Mode, typename Range>
range_adapter<Mode, Range>::range_adapter(iterator first, iterator last)
: first_(first), cur_(first), last_(last) { }
template<typename Mode, typename Range>
inline std::streamsize range_adapter<Mode, Range>::read
(char_type* s, std::streamsize n)
{ return impl::read(cur_, last_, s, n); }
template<typename Mode, typename Range>
inline std::streamsize range_adapter<Mode, Range>::write
(const char_type* s, std::streamsize n)
{ return impl::write(cur_, last_, s, n); }
template<typename Mode, typename Range>
std::streampos range_adapter<Mode, Range>::seek
(stream_offset off, BOOST_IOS::seekdir way)
{
impl::seek(first_, cur_, last_, off, way);
return offset_to_position(cur_ - first_);
}
//------------------Implementation of range_adapter_impl----------------------//
template<>
struct range_adapter_impl<std::forward_iterator_tag> {
template<typename Iter, typename Ch>
static std::streamsize read
(Iter& cur, Iter& last, Ch* s,std::streamsize n)
{
std::streamsize rem = n; // No. of chars remaining.
while (cur != last && rem-- > 0) *s++ = *cur++;
return n - rem != 0 ? n - rem : -1;
}
template<typename Iter, typename Ch>
static std::streamsize write
(Iter& cur, Iter& last, const Ch* s, std::streamsize n)
{
while (cur != last && n-- > 0) *cur++ = *s++;
if (cur == last && n > 0)
boost::throw_exception(write_area_exhausted());
return n;
}
};
template<>
struct range_adapter_impl<std::random_access_iterator_tag> {
template<typename Iter, typename Ch>
static std::streamsize read
(Iter& cur, Iter& last, Ch* s,std::streamsize n)
{
std::streamsize result =
(std::min)(static_cast<std::streamsize>(last - cur), n);
if (result)
std::copy(cur, cur + result, s);
cur += result;
return result != 0 ? result : -1;
}
template<typename Iter, typename Ch>
static std::streamsize write
(Iter& cur, Iter& last, const Ch* s, std::streamsize n)
{
std::streamsize count =
(std::min)(static_cast<std::streamsize>(last - cur), n);
std::copy(s, s + count, cur);
cur += count;
if (count < n)
boost::throw_exception(write_area_exhausted());
return n;
}
template<typename Iter>
static void seek
( Iter& first, Iter& cur, Iter& last, stream_offset off,
BOOST_IOS::seekdir way )
{
using namespace std;
switch (way) {
case BOOST_IOS::beg:
if (off > last - first || off < 0)
boost::throw_exception(bad_seek());
cur = first + off;
break;
case BOOST_IOS::cur:
{
std::ptrdiff_t newoff = cur - first + off;
if (newoff > last - first || newoff < 0)
boost::throw_exception(bad_seek());
cur += off;
break;
}
case BOOST_IOS::end:
if (last - first + off < 0 || off > 0)
boost::throw_exception(bad_seek());
cur = last + off;
break;
default:
BOOST_ASSERT(0);
}
}
};
} } } // End namespaces detail, iostreams, boost.
#include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC.
#endif // #ifndef BOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED //---------------//
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