boost/spirit/home/karma/directive/maxwidth.hpp
// Copyright (c) 2001-2011 Hartmut Kaiser // // 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) #if !defined(BOOST_SPIRIT_KARMA_MAXWIDTH_MAR_18_2009_0827AM) #define BOOST_SPIRIT_KARMA_MAXWIDTH_MAR_18_2009_0827AM #if defined(_MSC_VER) #pragma once #endif #include <boost/spirit/home/karma/meta_compiler.hpp> #include <boost/spirit/home/karma/generator.hpp> #include <boost/spirit/home/karma/domain.hpp> #include <boost/spirit/home/karma/detail/output_iterator.hpp> #include <boost/spirit/home/karma/detail/default_width.hpp> #include <boost/spirit/home/karma/delimit_out.hpp> #include <boost/spirit/home/karma/auxiliary/lazy.hpp> #include <boost/spirit/home/support/unused.hpp> #include <boost/spirit/home/support/common_terminals.hpp> #include <boost/spirit/home/support/has_semantic_action.hpp> #include <boost/spirit/home/support/handles_container.hpp> #include <boost/spirit/home/karma/detail/attributes.hpp> #include <boost/spirit/home/support/info.hpp> #include <boost/spirit/home/support/unused.hpp> #include <boost/fusion/include/at.hpp> #include <boost/fusion/include/vector.hpp> #include <boost/detail/workaround.hpp> /////////////////////////////////////////////////////////////////////////////// namespace boost { namespace spirit { /////////////////////////////////////////////////////////////////////////// // Enablers /////////////////////////////////////////////////////////////////////////// // enables maxwidth[] template <> struct use_directive<karma::domain, tag::maxwidth> : mpl::true_ {}; // enables maxwidth(w)[g], where w provides a maxwidth template <typename T> struct use_directive<karma::domain , terminal_ex<tag::maxwidth, fusion::vector1<T> > > : mpl::true_ {}; // enables *lazy* maxwidth(w)[g], where w provides a maxwidth template <> struct use_lazy_directive<karma::domain, tag::maxwidth, 1> : mpl::true_ {}; // enables maxwidth(w, r)[g], where w provides a maxwidth and r is an output // iterator used to receive the rest of the output not fitting into the // maxwidth limit template <typename T, typename RestIter> struct use_directive<karma::domain , terminal_ex<tag::maxwidth, fusion::vector2<T, RestIter> > > : mpl::true_ {}; // enables *lazy* maxwidth(w, r)[g], where w provides a maxwidth and r is // an output iterator used to receive the rest of the output not fitting // into the maxwidth limit template <> struct use_lazy_directive<karma::domain, tag::maxwidth, 2> : mpl::true_ {}; }} /////////////////////////////////////////////////////////////////////////////// namespace boost { namespace spirit { namespace karma { #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS using spirit::maxwidth; #endif using spirit::maxwidth_type; namespace detail { /////////////////////////////////////////////////////////////////////// template <typename OutputIterator, typename RestIterator> bool buffer_copy_rest(detail::enable_buffering<OutputIterator>& buff , std::size_t start_at, RestIterator& dest) { return buff.buffer_copy_rest(dest, start_at); } template <typename OutputIterator> bool buffer_copy_rest(detail::enable_buffering<OutputIterator>& , std::size_t, unused_type) { return true; } /////////////////////////////////////////////////////////////////////// // The maxwidth_generate template function is used for all the // different flavors of the maxwidth[] directive. /////////////////////////////////////////////////////////////////////// template <typename OutputIterator, typename Context, typename Delimiter, typename Attribute, typename Embedded, typename Rest> inline static bool maxwidth_generate(OutputIterator& sink, Context& ctx, Delimiter const& d, Attribute const& attr, Embedded const& e, unsigned int const maxwidth, Rest& restdest) { #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) (void)e; // suppresses warning: C4100: 'e' : unreferenced formal parameter #endif // wrap the given output iterator to allow buffering, but disable // counting detail::enable_buffering<OutputIterator> buffering(sink); // generate the underlying output and copy the embedded // output to the target output iterator applying the given // maxwidth bool r = false; { detail::disable_counting<OutputIterator> nocounting(sink); r = e.generate(sink, ctx, d, attr); } // re-enable counting return r && buffering.buffer_copy(maxwidth) && buffer_copy_rest(buffering, maxwidth, restdest); } } /////////////////////////////////////////////////////////////////////////// // The maxwidth directive is used for maxwidth[...] // generators. It uses default values for the generated width (defined via // the BOOST_KARMA_DEFAULT_FIELD_MAXWIDTH constant). // // The maxwidth with width directive, is used for generators // like maxwidth(width)[...]. /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Width = detail::default_max_width , typename Rest = unused_type> struct maxwidth_width : unary_generator<maxwidth_width<Subject, Width, Rest> > { typedef Subject subject_type; typedef mpl::int_< generator_properties::countingbuffer | subject_type::properties::value > properties; template <typename Context, typename Iterator> struct attribute : traits::attribute_of<subject_type, Context, Iterator> {}; maxwidth_width(Subject const& subject, Width const& w = Width() , Rest const& r = Rest()) : subject(subject), width(w), rest(r) {} template <typename OutputIterator, typename Context, typename Delimiter , typename Attribute> bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d , Attribute const& attr) const { return detail::maxwidth_generate(sink, ctx, d, attr, subject , width, rest); } template <typename Context> info what(Context& context) const { return info("maxwidth", subject.what(context)); } Subject subject; Width width; Rest rest; }; /////////////////////////////////////////////////////////////////////////// // Generator generators: make_xxx function (objects) /////////////////////////////////////////////////////////////////////////// // creates maxwidth[] directive generator template <typename Subject, typename Modifiers> struct make_directive<tag::maxwidth, Subject, Modifiers> { typedef maxwidth_width<Subject> result_type; result_type operator()(unused_type, Subject const& subject , unused_type) const { return result_type(subject); } }; // creates maxwidth(width)[] directive generator template <typename T, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::maxwidth, fusion::vector1<T> > , Subject, Modifiers> { typedef maxwidth_width<Subject, T> result_type; template <typename Terminal> result_type operator()(Terminal const& term, Subject const& subject , unused_type) const { return result_type(subject, fusion::at_c<0>(term.args), unused); } }; // creates maxwidth(width, restiter)[] directive generator template < typename T, typename RestIter, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::maxwidth, fusion::vector2<T, RestIter> > , Subject, Modifiers> { typedef maxwidth_width<Subject, T, RestIter> result_type; template <typename Terminal> result_type operator()(Terminal const& term, Subject const& subject , unused_type) const { return result_type(subject, fusion::at_c<0>(term.args) , fusion::at_c<1>(term.args)); } }; }}} // namespace boost::spirit::karma namespace boost { namespace spirit { namespace traits { /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Width, typename Rest> struct has_semantic_action<karma::maxwidth_width<Subject, Width, Rest> > : unary_has_semantic_action<Subject> {}; /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Attribute, typename Context , typename Iterator> struct handles_container<karma::maxwidth_width<Subject>, Attribute , Context, Iterator> : unary_handles_container<Subject, Attribute, Context, Iterator> {}; }}} #endif