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1 | // Copyright (c) 2001-2011 Hartmut Kaiser |
2 | // | |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
5 | ||
6 | #if !defined(SPIRIT_KARMA_BUFFER_AUG_03_2009_0949AM) | |
7 | #define SPIRIT_KARMA_BUFFER_AUG_03_2009_0949AM | |
8 | ||
9 | #if defined(_MSC_VER) | |
10 | #pragma once | |
11 | #endif | |
12 | ||
13 | #include <boost/spirit/home/karma/meta_compiler.hpp> | |
14 | #include <boost/spirit/home/karma/generator.hpp> | |
15 | #include <boost/spirit/home/karma/domain.hpp> | |
16 | #include <boost/spirit/home/karma/detail/output_iterator.hpp> | |
17 | #include <boost/spirit/home/support/unused.hpp> | |
18 | #include <boost/spirit/home/support/info.hpp> | |
19 | #include <boost/spirit/home/support/common_terminals.hpp> | |
20 | #include <boost/spirit/home/support/has_semantic_action.hpp> | |
21 | #include <boost/spirit/home/support/handles_container.hpp> | |
22 | #include <boost/spirit/home/karma/detail/attributes.hpp> | |
23 | ||
24 | namespace boost { namespace spirit | |
25 | { | |
26 | /////////////////////////////////////////////////////////////////////////// | |
27 | // Enablers | |
28 | /////////////////////////////////////////////////////////////////////////// | |
29 | template <> | |
30 | struct use_directive<karma::domain, tag::buffer> // enables buffer | |
31 | : mpl::true_ {}; | |
32 | ||
33 | }} | |
34 | ||
35 | namespace boost { namespace spirit { namespace karma | |
36 | { | |
37 | #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS | |
38 | using spirit::buffer; | |
39 | #endif | |
40 | using spirit::buffer_type; | |
41 | ||
42 | /////////////////////////////////////////////////////////////////////////// | |
43 | // buffer_directive buffers all generated output of the embedded generator | |
44 | // and flushes it only if the whole embedded generator succeeds | |
45 | /////////////////////////////////////////////////////////////////////////// | |
46 | template <typename Subject> | |
47 | struct buffer_directive : unary_generator<buffer_directive<Subject> > | |
48 | { | |
49 | typedef Subject subject_type; | |
50 | typedef mpl::int_< | |
51 | subject_type::properties::value | | |
52 | generator_properties::countingbuffer | |
53 | > properties; | |
54 | ||
55 | buffer_directive(Subject const& subject) | |
56 | : subject(subject) {} | |
57 | ||
58 | template <typename Context, typename Iterator> | |
59 | struct attribute | |
60 | : traits::attribute_of<subject_type, Context, Iterator> | |
61 | {}; | |
62 | ||
63 | template <typename OutputIterator, typename Context, typename Delimiter | |
64 | , typename Attribute> | |
65 | bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d | |
66 | , Attribute const& attr) const | |
67 | { | |
68 | // wrap the given output iterator to avoid output as long as the | |
69 | // embedded generator (subject) fails | |
70 | detail::enable_buffering<OutputIterator> buffering(sink); | |
71 | bool r = false; | |
72 | { | |
73 | detail::disable_counting<OutputIterator> nocounting(sink); | |
74 | r = subject.generate(sink, ctx, d, attr); | |
75 | } | |
76 | if (r) | |
77 | buffering.buffer_copy(); | |
78 | return r; | |
79 | } | |
80 | ||
81 | template <typename Context> | |
82 | info what(Context& context) const | |
83 | { | |
84 | return info("buffer", subject.what(context)); | |
85 | } | |
86 | ||
87 | Subject subject; | |
88 | }; | |
89 | ||
90 | /////////////////////////////////////////////////////////////////////////// | |
91 | // Generator generators: make_xxx function (objects) | |
92 | /////////////////////////////////////////////////////////////////////////// | |
93 | template <typename Subject, typename Modifiers> | |
94 | struct make_directive<tag::buffer, Subject, Modifiers> | |
95 | { | |
96 | typedef buffer_directive<Subject> result_type; | |
97 | result_type operator()(unused_type, Subject const& subject | |
98 | , unused_type) const | |
99 | { | |
100 | return result_type(subject); | |
101 | } | |
102 | }; | |
103 | ||
104 | // make sure buffer[buffer[...]] does not result in double buffering | |
105 | template <typename Subject, typename Modifiers> | |
106 | struct make_directive<tag::buffer, buffer_directive<Subject>, Modifiers> | |
107 | { | |
108 | typedef buffer_directive<Subject> result_type; | |
109 | result_type operator()(unused_type | |
110 | , buffer_directive<Subject> const& subject, unused_type) const | |
111 | { | |
112 | return subject; | |
113 | } | |
114 | }; | |
115 | }}} | |
116 | ||
117 | namespace boost { namespace spirit { namespace traits | |
118 | { | |
119 | /////////////////////////////////////////////////////////////////////////// | |
120 | template <typename Subject> | |
121 | struct has_semantic_action<karma::buffer_directive<Subject> > | |
122 | : unary_has_semantic_action<Subject> {}; | |
123 | ||
124 | /////////////////////////////////////////////////////////////////////////// | |
125 | template <typename Subject, typename Attribute, typename Context | |
126 | , typename Iterator> | |
127 | struct handles_container<karma::buffer_directive<Subject>, Attribute | |
128 | , Context, Iterator> | |
129 | : unary_handles_container<Subject, Attribute, Context, Iterator> {}; | |
130 | }}} | |
131 | ||
132 | #endif |