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(BOOST_SPIRIT_KARMA_CENTER_ALIGNMENT_FEB_27_2007_1216PM)
7 #define BOOST_SPIRIT_KARMA_CENTER_ALIGNMENT_FEB_27_2007_1216PM
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/karma/detail/default_width.hpp>
18 #include <boost/spirit/home/karma/delimit_out.hpp>
19 #include <boost/spirit/home/karma/auxiliary/lazy.hpp>
20 #include <boost/spirit/home/support/unused.hpp>
21 #include <boost/spirit/home/support/common_terminals.hpp>
22 #include <boost/spirit/home/support/has_semantic_action.hpp>
23 #include <boost/spirit/home/support/handles_container.hpp>
24 #include <boost/spirit/home/karma/detail/attributes.hpp>
25 #include <boost/spirit/home/support/info.hpp>
26 #include <boost/spirit/home/support/unused.hpp>
27 #include <boost/fusion/include/at.hpp>
28 #include <boost/fusion/include/vector.hpp>
29 #include <boost/integer_traits.hpp>
30 #include <boost/mpl/bool.hpp>
31 #include <boost/utility/enable_if.hpp>
32 #include <boost/detail/workaround.hpp>
33 
34 ///////////////////////////////////////////////////////////////////////////////
35 namespace boost { namespace spirit
36 {
37     ///////////////////////////////////////////////////////////////////////////
38     // Enablers
39     ///////////////////////////////////////////////////////////////////////////
40 
41     // enables center[]
42     template <>
43     struct use_directive<karma::domain, tag::center>
44       : mpl::true_ {};
45 
46     // enables center(d)[g] and center(w)[g], where d is a generator
47     // and w is a maximum width
48     template <typename T>
49     struct use_directive<karma::domain
50           , terminal_ex<tag::center, fusion::vector1<T> > >
51       : mpl::true_ {};
52 
53     // enables *lazy* center(d)[g], where d provides a generator
54     template <>
55     struct use_lazy_directive<karma::domain, tag::center, 1>
56       : mpl::true_ {};
57 
58     // enables center(w, d)[g], where d is a generator and w is a maximum
59     // width
60     template <typename Width, typename Padding>
61     struct use_directive<karma::domain
62           , terminal_ex<tag::center, fusion::vector2<Width, Padding> > >
63       : spirit::traits::matches<karma::domain, Padding> {};
64 
65     // enables *lazy* center(w, d)[g], where d provides a generator and w is
66     // a maximum width
67     template <>
68     struct use_lazy_directive<karma::domain, tag::center, 2>
69       : mpl::true_ {};
70 
71 }}
72 
73 ///////////////////////////////////////////////////////////////////////////////
74 namespace boost { namespace spirit { namespace karma
75 {
76 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
77     using spirit::center;
78 #endif
79     using spirit::center_type;
80 
81     namespace detail
82     {
83         ///////////////////////////////////////////////////////////////////////
84         //  The center_generate template function is used for all the
85         //  different flavors of the center[] directive.
86         ///////////////////////////////////////////////////////////////////////
87         template <typename OutputIterator, typename Context, typename Delimiter,
88             typename Attribute, typename Embedded, typename Padding>
89         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)90         center_generate(OutputIterator& sink, Context& ctx,
91             Delimiter const& d, Attribute const& attr, Embedded const& e,
92             unsigned int const width, Padding const& p)
93         {
94 #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600))
95             e; // suppresses warning: C4100: 'e' : unreferenced formal parameter
96 #endif
97             // wrap the given output iterator to allow left padding
98             detail::enable_buffering<OutputIterator> buffering(sink, width);
99             bool r = false;
100 
101             // first generate the embedded output
102             {
103                 detail::disable_counting<OutputIterator> nocounting(sink);
104                 r = e.generate(sink, ctx, d, attr);
105             }   // re-enable counting
106 
107             buffering.disable();    // do not perform buffering any more
108 
109             // generate the left padding
110             detail::enable_counting<OutputIterator> counting(sink);
111 
112             std::size_t const pre = width - (buffering.buffer_size() + width)/2;
113             while (r && counting.count() < pre)
114                 r = p.generate(sink, ctx, unused, unused);
115 
116             if (r) {
117                 // copy the embedded output to the target output iterator
118                 buffering.buffer_copy();
119 
120                 // generate the right padding
121                 while (r && counting.count() < width)
122                     r = p.generate(sink, ctx, unused, unused);
123             }
124             return r;
125         }
126     }
127 
128     ///////////////////////////////////////////////////////////////////////////
129     //  The simple left alignment directive is used for center[...]
130     //  generators. It uses default values for the generated width (defined via
131     //  the BOOST_KARMA_DEFAULT_FIELD_LENGTH constant) and for the padding
132     //  generator (always spaces).
133     ///////////////////////////////////////////////////////////////////////////
134     template <typename Subject, typename Width = detail::default_width>
135     struct simple_center_alignment
136       : unary_generator<simple_center_alignment<Subject, Width> >
137     {
138         typedef Subject subject_type;
139 
140         typedef mpl::int_<
141             generator_properties::countingbuffer | subject_type::properties::value
142         > properties;
143 
144         template <typename Context, typename Iterator>
145         struct attribute
146           : traits::attribute_of<subject_type, Context, Iterator>
147         {};
148 
simple_center_alignmentboost::spirit::karma::simple_center_alignment149         simple_center_alignment(Subject const& subject, Width width = Width())
150           : subject(subject), width(width) {}
151 
152         template <typename OutputIterator, typename Context, typename Delimiter
153           , typename Attribute>
generateboost::spirit::karma::simple_center_alignment154         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
155           , Attribute const& attr) const
156         {
157             return detail::center_generate(sink, ctx, d, attr,
158                 subject, width, compile<karma::domain>(' '));
159         }
160 
161         template <typename Context>
whatboost::spirit::karma::simple_center_alignment162         info what(Context& context) const
163         {
164             return info("center", subject.what(context));
165         }
166 
167         Subject subject;
168         Width width;
169     };
170 
171     ///////////////////////////////////////////////////////////////////////////
172     //  The left alignment directive with padding, is used for generators like
173     //  center(padding)[...], where padding is a arbitrary generator
174     //  expression. It uses a default value for the generated width (defined
175     //  via the BOOST_KARMA_DEFAULT_FIELD_LENGTH constant).
176     ///////////////////////////////////////////////////////////////////////////
177     template <typename Subject, typename Padding
178       , typename Width = detail::default_width>
179     struct padding_center_alignment
180       : unary_generator<padding_center_alignment<Subject, Padding, Width> >
181     {
182         typedef Subject subject_type;
183         typedef Padding padding_type;
184 
185         typedef mpl::int_<
186             generator_properties::countingbuffer |
187             subject_type::properties::value | padding_type::properties::value
188         > properties;
189 
190         template <typename Context, typename Iterator>
191         struct attribute
192           : traits::attribute_of<Subject, Context, Iterator>
193         {};
194 
padding_center_alignmentboost::spirit::karma::padding_center_alignment195         padding_center_alignment(Subject const& subject, Padding const& padding
196               , Width width = Width())
197           : subject(subject), padding(padding), width(width) {}
198 
199         template <typename OutputIterator, typename Context, typename Delimiter
200           , typename Attribute>
generateboost::spirit::karma::padding_center_alignment201         bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
202           , Attribute const& attr) const
203         {
204             return detail::center_generate(sink, ctx, d, attr,
205                 subject, width, padding);
206         }
207 
208         template <typename Context>
whatboost::spirit::karma::padding_center_alignment209         info what(Context& context) const
210         {
211             return info("center", subject.what(context));
212         }
213 
214         Subject subject;
215         Padding padding;
216         Width width;
217     };
218 
219     ///////////////////////////////////////////////////////////////////////////
220     // Generator generators: make_xxx function (objects)
221     ///////////////////////////////////////////////////////////////////////////
222 
223     // creates center[] directive generator
224     template <typename Subject, typename Modifiers>
225     struct make_directive<tag::center, Subject, Modifiers>
226     {
227         typedef simple_center_alignment<Subject> result_type;
operator ()boost::spirit::karma::make_directive228         result_type operator()(unused_type, Subject const& subject
229           , unused_type) const
230         {
231             return result_type(subject);
232         }
233     };
234 
235     // creates center(width)[] directive generator
236     template <typename Width, typename Subject, typename Modifiers>
237     struct make_directive<
238         terminal_ex<tag::center, fusion::vector1<Width> >
239       , Subject, Modifiers
240       , typename enable_if_c< integer_traits<Width>::is_integral >::type>
241     {
242         typedef simple_center_alignment<Subject, Width> result_type;
243 
244         template <typename Terminal>
operator ()boost::spirit::karma::make_directive245         result_type operator()(Terminal const& term, Subject const& subject
246           , unused_type) const
247         {
248             return result_type(subject, fusion::at_c<0>(term.args));
249         }
250     };
251 
252     // creates center(pad)[] directive generator
253     template <typename Padding, typename Subject, typename Modifiers>
254     struct make_directive<
255         terminal_ex<tag::center, fusion::vector1<Padding> >
256       , Subject, Modifiers
257       , typename enable_if<
258             mpl::and_<
259                 spirit::traits::matches<karma::domain, Padding>,
260                 mpl::not_<mpl::bool_<integer_traits<Padding>::is_integral> >
261             >
262         >::type>
263     {
264         typedef typename
265             result_of::compile<karma::domain, Padding, Modifiers>::type
266         padding_type;
267 
268         typedef padding_center_alignment<Subject, padding_type> result_type;
269 
270         template <typename Terminal>
operator ()boost::spirit::karma::make_directive271         result_type operator()(Terminal const& term, Subject const& subject
272           , Modifiers const& modifiers) const
273         {
274             return result_type(subject
275               , compile<karma::domain>(fusion::at_c<0>(term.args), modifiers));
276         }
277     };
278 
279     // creates center(width, pad)[] directive generator
280     template <typename Width, typename Padding, typename Subject
281       , typename Modifiers>
282     struct make_directive<
283         terminal_ex<tag::center, fusion::vector2<Width, Padding> >
284       , Subject, Modifiers>
285     {
286         typedef typename
287             result_of::compile<karma::domain, Padding, Modifiers>::type
288         padding_type;
289 
290         typedef padding_center_alignment<Subject, padding_type, Width> result_type;
291 
292         template <typename Terminal>
operator ()boost::spirit::karma::make_directive293         result_type operator()(Terminal const& term, Subject const& subject
294           , Modifiers const& modifiers) const
295         {
296             return result_type(subject
297               , compile<karma::domain>(fusion::at_c<1>(term.args), modifiers)
298               , fusion::at_c<0>(term.args));
299         }
300     };
301 
302 }}} // namespace boost::spirit::karma
303 
304 namespace boost { namespace spirit { namespace traits
305 {
306     ///////////////////////////////////////////////////////////////////////////
307     template <typename Subject, typename Width>
308     struct has_semantic_action<karma::simple_center_alignment<Subject, Width> >
309       : unary_has_semantic_action<Subject> {};
310 
311     template <typename Subject, typename Padding, typename Width>
312     struct has_semantic_action<
313             karma::padding_center_alignment<Subject, Padding, Width> >
314       : unary_has_semantic_action<Subject> {};
315 
316     ///////////////////////////////////////////////////////////////////////////
317     template <typename Subject, typename Width, typename Attribute
318       , typename Context, typename Iterator>
319     struct handles_container<
320             karma::simple_center_alignment<Subject, Width>, Attribute
321           , Context, Iterator>
322       : unary_handles_container<Subject, Attribute, Context, Iterator> {};
323 
324     template <typename Subject, typename Padding, typename Width
325       , typename Attribute, typename Context, typename Iterator>
326     struct handles_container<
327             karma::padding_center_alignment<Subject, Padding, Width>
328           , Attribute, Context, Iterator>
329       : unary_handles_container<Subject, Attribute, Context, Iterator> {};
330 }}}
331 
332 #endif
333 
334 
335