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center_alignment.hpp
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// 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_CENTER_ALIGNMENT_FEB_27_2007_1216PM) #define BOOST_SPIRIT_KARMA_CENTER_ALIGNMENT_FEB_27_2007_1216PM #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/integer_traits.hpp> #include <boost/mpl/bool.hpp> #include <boost/utility/enable_if.hpp> #include <boost/detail/workaround.hpp> /////////////////////////////////////////////////////////////////////////////// namespace boost { namespace spirit { /////////////////////////////////////////////////////////////////////////// // Enablers /////////////////////////////////////////////////////////////////////////// // enables center[] template <> struct use_directive<karma::domain, tag::center> : mpl::true_ {}; // enables center(d)[g] and center(w)[g], where d is a generator // and w is a maximum width template <typename T> struct use_directive<karma::domain , terminal_ex<tag::center, fusion::vector1<T> > > : mpl::true_ {}; // enables *lazy* center(d)[g], where d provides a generator template <> struct use_lazy_directive<karma::domain, tag::center, 1> : mpl::true_ {}; // enables center(w, d)[g], where d is a generator and w is a maximum // width template <typename Width, typename Padding> struct use_directive<karma::domain , terminal_ex<tag::center, fusion::vector2<Width, Padding> > > : spirit::traits::matches<karma::domain, Padding> {}; // enables *lazy* center(w, d)[g], where d provides a generator and w is // a maximum width template <> struct use_lazy_directive<karma::domain, tag::center, 2> : mpl::true_ {}; }} /////////////////////////////////////////////////////////////////////////////// namespace boost { namespace spirit { namespace karma { #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS using spirit::center; #endif using spirit::center_type; namespace detail { /////////////////////////////////////////////////////////////////////// // The center_generate template function is used for all the // different flavors of the center[] directive. /////////////////////////////////////////////////////////////////////// template <typename OutputIterator, typename Context, typename Delimiter, typename Attribute, typename Embedded, typename Padding> inline static bool center_generate(OutputIterator& sink, Context& ctx, Delimiter const& d, Attribute const& attr, Embedded const& e, unsigned int const width, Padding const& p) { #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600)) e; // suppresses warning: C4100: 'e' : unreferenced formal parameter #endif // wrap the given output iterator to allow left padding detail::enable_buffering<OutputIterator> buffering(sink, width); bool r = false; // first generate the embedded output { detail::disable_counting<OutputIterator> nocounting(sink); r = e.generate(sink, ctx, d, attr); } // re-enable counting buffering.disable(); // do not perform buffering any more // generate the left padding detail::enable_counting<OutputIterator> counting(sink); std::size_t const pre = width - (buffering.buffer_size() + width)/2; while (r && counting.count() < pre) r = p.generate(sink, ctx, unused, unused); if (r) { // copy the embedded output to the target output iterator buffering.buffer_copy(); // generate the right padding while (r && counting.count() < width) r = p.generate(sink, ctx, unused, unused); } return r; } } /////////////////////////////////////////////////////////////////////////// // The simple left alignment directive is used for center[...] // generators. It uses default values for the generated width (defined via // the BOOST_KARMA_DEFAULT_FIELD_LENGTH constant) and for the padding // generator (always spaces). /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Width = detail::default_width> struct simple_center_alignment : unary_generator<simple_center_alignment<Subject, Width> > { 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> {}; simple_center_alignment(Subject const& subject, Width width = Width()) : subject(subject), width(width) {} template <typename OutputIterator, typename Context, typename Delimiter , typename Attribute> bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d , Attribute const& attr) const { return detail::center_generate(sink, ctx, d, attr, subject, width, compile<karma::domain>(' ')); } template <typename Context> info what(Context& context) const { return info("center", subject.what(context)); } Subject subject; Width width; }; /////////////////////////////////////////////////////////////////////////// // The left alignment directive with padding, is used for generators like // center(padding)[...], where padding is a arbitrary generator // expression. It uses a default value for the generated width (defined // via the BOOST_KARMA_DEFAULT_FIELD_LENGTH constant). /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Padding , typename Width = detail::default_width> struct padding_center_alignment : unary_generator<padding_center_alignment<Subject, Padding, Width> > { typedef Subject subject_type; typedef Padding padding_type; typedef mpl::int_< generator_properties::countingbuffer | subject_type::properties::value | padding_type::properties::value > properties; template <typename Context, typename Iterator> struct attribute : traits::attribute_of<Subject, Context, Iterator> {}; padding_center_alignment(Subject const& subject, Padding const& padding , Width width = Width()) : subject(subject), padding(padding), width(width) {} template <typename OutputIterator, typename Context, typename Delimiter , typename Attribute> bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d , Attribute const& attr) const { return detail::center_generate(sink, ctx, d, attr, subject, width, padding); } template <typename Context> info what(Context& context) const { return info("center", subject.what(context)); } Subject subject; Padding padding; Width width; }; /////////////////////////////////////////////////////////////////////////// // Generator generators: make_xxx function (objects) /////////////////////////////////////////////////////////////////////////// // creates center[] directive generator template <typename Subject, typename Modifiers> struct make_directive<tag::center, Subject, Modifiers> { typedef simple_center_alignment<Subject> result_type; result_type operator()(unused_type, Subject const& subject , unused_type) const { return result_type(subject); } }; // creates center(width)[] directive generator template <typename Width, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::center, fusion::vector1<Width> > , Subject, Modifiers , typename enable_if_c< integer_traits<Width>::is_integral >::type> { typedef simple_center_alignment<Subject, Width> 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)); } }; // creates center(pad)[] directive generator template <typename Padding, typename Subject, typename Modifiers> struct make_directive< terminal_ex<tag::center, fusion::vector1<Padding> > , Subject, Modifiers , typename enable_if< mpl::and_< spirit::traits::matches<karma::domain, Padding>, mpl::not_<mpl::bool_<integer_traits<Padding>::is_integral> > > >::type> { typedef typename result_of::compile<karma::domain, Padding, Modifiers>::type padding_type; typedef padding_center_alignment<Subject, padding_type> result_type; template <typename Terminal> result_type operator()(Terminal const& term, Subject const& subject , Modifiers const& modifiers) const { return result_type(subject , compile<karma::domain>(fusion::at_c<0>(term.args), modifiers)); } }; // creates center(width, pad)[] directive generator template <typename Width, typename Padding, typename Subject , typename Modifiers> struct make_directive< terminal_ex<tag::center, fusion::vector2<Width, Padding> > , Subject, Modifiers> { typedef typename result_of::compile<karma::domain, Padding, Modifiers>::type padding_type; typedef padding_center_alignment<Subject, padding_type, Width> result_type; template <typename Terminal> result_type operator()(Terminal const& term, Subject const& subject , Modifiers const& modifiers) const { return result_type(subject , compile<karma::domain>(fusion::at_c<1>(term.args), modifiers) , fusion::at_c<0>(term.args)); } }; }}} // namespace boost::spirit::karma namespace boost { namespace spirit { namespace traits { /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Width> struct has_semantic_action<karma::simple_center_alignment<Subject, Width> > : unary_has_semantic_action<Subject> {}; template <typename Subject, typename Padding, typename Width> struct has_semantic_action< karma::padding_center_alignment<Subject, Padding, Width> > : unary_has_semantic_action<Subject> {}; /////////////////////////////////////////////////////////////////////////// template <typename Subject, typename Width, typename Attribute , typename Context, typename Iterator> struct handles_container< karma::simple_center_alignment<Subject, Width>, Attribute , Context, Iterator> : unary_handles_container<Subject, Attribute, Context, Iterator> {}; template <typename Subject, typename Padding, typename Width , typename Attribute, typename Context, typename Iterator> struct handles_container< karma::padding_center_alignment<Subject, Padding, Width> , Attribute, Context, Iterator> : unary_handles_container<Subject, Attribute, Context, Iterator> {}; }}} #endif