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132 lines
4.7 KiB
132 lines
4.7 KiB
// 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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#if !defined(SPIRIT_KARMA_BUFFER_AUG_03_2009_0949AM) |
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#define SPIRIT_KARMA_BUFFER_AUG_03_2009_0949AM |
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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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