// Copyright (c) 2001-2011 Hartmut Kaiser
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_SPIRIT_KARMA_DIRECTIVE_BUFFER_HPP
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#define BOOST_SPIRIT_KARMA_DIRECTIVE_BUFFER_HPP
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/spirit/home/karma/meta_compiler.hpp>
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#include <boost/spirit/home/karma/generator.hpp>
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#include <boost/spirit/home/karma/domain.hpp>
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#include <boost/spirit/home/karma/detail/output_iterator.hpp>
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#include <boost/spirit/home/support/unused.hpp>
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#include <boost/spirit/home/support/info.hpp>
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#include <boost/spirit/home/support/common_terminals.hpp>
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#include <boost/spirit/home/support/has_semantic_action.hpp>
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#include <boost/spirit/home/support/handles_container.hpp>
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#include <boost/spirit/home/karma/detail/attributes.hpp>
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namespace boost { namespace spirit
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{
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///////////////////////////////////////////////////////////////////////////
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// Enablers
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///////////////////////////////////////////////////////////////////////////
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template <>
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struct use_directive<karma::domain, tag::buffer> // enables buffer
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: mpl::true_ {};
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}}
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namespace boost { namespace spirit { namespace karma
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{
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#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
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using spirit::buffer;
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#endif
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using spirit::buffer_type;
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///////////////////////////////////////////////////////////////////////////
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// buffer_directive buffers all generated output of the embedded generator
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// and flushes it only if the whole embedded generator succeeds
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject>
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struct buffer_directive : unary_generator<buffer_directive<Subject> >
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{
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typedef Subject subject_type;
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typedef mpl::int_<
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subject_type::properties::value |
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generator_properties::countingbuffer
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> properties;
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buffer_directive(Subject const& subject)
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: subject(subject) {}
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template <typename Context, typename Iterator>
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struct attribute
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: traits::attribute_of<subject_type, Context, Iterator>
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{};
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template <typename OutputIterator, typename Context, typename Delimiter
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, typename Attribute>
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bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
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, Attribute const& attr) const
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{
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// wrap the given output iterator to avoid output as long as the
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// embedded generator (subject) fails
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detail::enable_buffering<OutputIterator> buffering(sink);
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bool r = false;
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{
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detail::disable_counting<OutputIterator> nocounting(sink);
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r = subject.generate(sink, ctx, d, attr);
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}
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if (r)
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buffering.buffer_copy();
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return r;
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}
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template <typename Context>
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info what(Context& context) const
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{
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return info("buffer", subject.what(context));
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}
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Subject subject;
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};
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///////////////////////////////////////////////////////////////////////////
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// Generator generators: make_xxx function (objects)
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename Modifiers>
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struct make_directive<tag::buffer, Subject, Modifiers>
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{
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typedef buffer_directive<Subject> result_type;
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result_type operator()(unused_type, Subject const& subject
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, unused_type) const
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{
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return result_type(subject);
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}
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};
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// make sure buffer[buffer[...]] does not result in double buffering
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template <typename Subject, typename Modifiers>
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struct make_directive<tag::buffer, buffer_directive<Subject>, Modifiers>
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{
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typedef buffer_directive<Subject> result_type;
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result_type operator()(unused_type
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, buffer_directive<Subject> const& subject, unused_type) const
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{
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return subject;
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}
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};
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}}}
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namespace boost { namespace spirit { namespace traits
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{
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject>
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struct has_semantic_action<karma::buffer_directive<Subject> >
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: unary_has_semantic_action<Subject> {};
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename Attribute, typename Context
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, typename Iterator>
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struct handles_container<karma::buffer_directive<Subject>, Attribute
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, Context, Iterator>
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: unary_handles_container<Subject, Attribute, Context, Iterator> {};
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}}}
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#endif
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