Chris@16: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
Chris@16: // (C) Copyright 2003-2007 Jonathan Turkanis
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16: 
Chris@16: // See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif              
Chris@16: 
Chris@16: #include <algorithm>                             // min.
Chris@16: #include <boost/assert.hpp>
Chris@16: #include <cstddef>                               // ptrdiff_t.
Chris@16: #include <iosfwd>                                // streamsize, streamoff.
Chris@16: #include <boost/detail/iterator.hpp>             // boost::iterator_traits.
Chris@16: #include <boost/iostreams/categories.hpp>
Chris@16: #include <boost/iostreams/detail/error.hpp>
Chris@16: #include <boost/iostreams/positioning.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/throw_exception.hpp>
Chris@16: #include <boost/type_traits/is_convertible.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: 
Chris@16: // Must come last.
Chris@16: #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.
Chris@16: 
Chris@16: namespace boost { namespace iostreams { namespace detail {
Chris@16: 
Chris@16: // Used for simulated tag dispatch.
Chris@16: template<typename Traversal> struct range_adapter_impl;
Chris@16: 
Chris@16: //
Chris@16: // Template name: range_adapter
Chris@16: // Description: Device based on an instance of boost::iterator_range.
Chris@16: // Template parameters:
Chris@16: //     Mode - A mode tag.
Chris@16: //     Range - An instance of iterator_range.
Chris@16: //
Chris@16: template<typename Mode, typename Range>
Chris@16: class range_adapter {
Chris@16: private:
Chris@16:     typedef typename Range::iterator                  iterator;
Chris@16:     typedef boost::detail::iterator_traits<iterator>  iter_traits;
Chris@16:     typedef typename iter_traits::iterator_category   iter_cat;
Chris@16: public:
Chris@16:     typedef typename Range::value_type                char_type;
Chris@16:     struct category : Mode, device_tag { };
Chris@16:     typedef typename
Chris@16:             mpl::if_<
Chris@16:                 is_convertible<
Chris@16:                     iter_cat,
Chris@16:                     std::random_access_iterator_tag
Chris@16:                 >,
Chris@16:                 std::random_access_iterator_tag,
Chris@16:                 std::forward_iterator_tag
Chris@16:             >::type                                   tag;
Chris@16:     typedef range_adapter_impl<tag>                   impl;
Chris@16: 
Chris@16:     explicit range_adapter(const Range& rng);
Chris@16:     range_adapter(iterator first, iterator last);
Chris@16:     std::streamsize read(char_type* s, std::streamsize n);
Chris@16:     std::streamsize write(const char_type* s, std::streamsize n);
Chris@16:     std::streampos seek(stream_offset off, BOOST_IOS::seekdir way);
Chris@16: private:
Chris@16:     iterator first_, cur_, last_;
Chris@16: };
Chris@16: 
Chris@16: //------------------Implementation of range_adapter---------------------------//
Chris@16: 
Chris@16: template<typename Mode, typename Range>
Chris@16: range_adapter<Mode, Range>::range_adapter(const Range& rng)
Chris@16:     : first_(rng.begin()), cur_(rng.begin()), last_(rng.end()) { }
Chris@16: 
Chris@16: template<typename Mode, typename Range>
Chris@16: range_adapter<Mode, Range>::range_adapter(iterator first, iterator last)
Chris@16:     : first_(first), cur_(first), last_(last) { }
Chris@16: 
Chris@16: template<typename Mode, typename Range>
Chris@16: inline std::streamsize range_adapter<Mode, Range>::read
Chris@16:     (char_type* s, std::streamsize n)
Chris@16: { return impl::read(cur_, last_, s, n); }
Chris@16: 
Chris@16: template<typename Mode, typename Range>
Chris@16: inline std::streamsize range_adapter<Mode, Range>::write
Chris@16:     (const char_type* s, std::streamsize n)
Chris@16: { return impl::write(cur_, last_, s, n); }
Chris@16: 
Chris@16: 
Chris@16: template<typename Mode, typename Range>
Chris@16: std::streampos range_adapter<Mode, Range>::seek
Chris@16:     (stream_offset off, BOOST_IOS::seekdir way)
Chris@16: { 
Chris@16:     impl::seek(first_, cur_, last_, off, way); 
Chris@16:     return offset_to_position(cur_ - first_);
Chris@16: }
Chris@16: 
Chris@16: //------------------Implementation of range_adapter_impl----------------------//
Chris@16: 
Chris@16: template<>
Chris@16: struct range_adapter_impl<std::forward_iterator_tag> {
Chris@16:     template<typename Iter, typename Ch>
Chris@16:     static std::streamsize read
Chris@16:         (Iter& cur, Iter& last, Ch* s,std::streamsize n)
Chris@16:     {
Chris@16:         std::streamsize rem = n; // No. of chars remaining.
Chris@16:         while (cur != last && rem-- > 0) *s++ = *cur++;
Chris@16:         return n - rem != 0 ? n - rem : -1;
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Iter, typename Ch>
Chris@16:     static std::streamsize write
Chris@16:         (Iter& cur, Iter& last, const Ch* s, std::streamsize n)
Chris@16:     {
Chris@16:         while (cur != last && n-- > 0) *cur++ = *s++;
Chris@16:         if (cur == last && n > 0)
Chris@16:             boost::throw_exception(write_area_exhausted());
Chris@16:         return n;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct range_adapter_impl<std::random_access_iterator_tag> {
Chris@16:     template<typename Iter, typename Ch>
Chris@16:     static std::streamsize read
Chris@16:         (Iter& cur, Iter& last, Ch* s,std::streamsize n)
Chris@16:     {
Chris@16:         std::streamsize result = 
Chris@16:             (std::min)(static_cast<std::streamsize>(last - cur), n);
Chris@16:         if (result)
Chris@16:             std::copy(cur, cur + result, s);
Chris@16:         cur += result;
Chris@16:         return result != 0 ? result : -1;
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Iter, typename Ch>
Chris@16:     static std::streamsize write
Chris@16:         (Iter& cur, Iter& last, const Ch* s, std::streamsize n)
Chris@16:     {
Chris@16:         std::streamsize count =
Chris@16:             (std::min)(static_cast<std::streamsize>(last - cur), n);
Chris@16:         std::copy(s, s + count, cur);
Chris@16:         cur += count;
Chris@16:         if (count < n) 
Chris@16:             boost::throw_exception(write_area_exhausted());
Chris@16:         return n;
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Iter>
Chris@16:     static void seek
Chris@16:         ( Iter& first, Iter& cur, Iter& last, stream_offset off,
Chris@16:           BOOST_IOS::seekdir way )
Chris@16:     {
Chris@16:         using namespace std;
Chris@16:         switch (way) {
Chris@16:         case BOOST_IOS::beg:
Chris@16:             if (off > last - first || off < 0)
Chris@16:                 boost::throw_exception(bad_seek());
Chris@16:             cur = first + off;
Chris@16:             break;
Chris@16:         case BOOST_IOS::cur:
Chris@16:             {
Chris@16:                 std::ptrdiff_t newoff = cur - first + off;
Chris@16:                 if (newoff > last - first || newoff < 0)
Chris@16:                     boost::throw_exception(bad_seek());
Chris@16:                 cur += off;
Chris@16:                 break;
Chris@16:             }
Chris@16:         case BOOST_IOS::end:
Chris@16:             if (last - first + off < 0 || off > 0)
Chris@16:                 boost::throw_exception(bad_seek());
Chris@16:             cur = last + off;
Chris@16:             break;
Chris@16:         default:
Chris@16:             BOOST_ASSERT(0);
Chris@16:         }
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } } } // End namespaces detail, iostreams, boost.
Chris@16: 
Chris@16: #include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED //---------------//