summaryrefslogtreecommitdiff
path: root/boost/spirit/home/karma/detail/output_iterator.hpp
blob: 75c984a9bc1194cbe6c492f36b49dfc693c0b5fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
//  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_OUTPUT_ITERATOR_MAY_26_2007_0506PM)
#define BOOST_SPIRIT_KARMA_OUTPUT_ITERATOR_MAY_26_2007_0506PM

#if defined(_MSC_VER)
#pragma once
#endif

#include <iterator>
#include <vector>
#include <algorithm>

#include <boost/config.hpp>
#include <boost/noncopyable.hpp>
#include <boost/mpl/if.hpp>

#include <boost/spirit/home/karma/generator.hpp>
#include <boost/spirit/home/support/iterators/ostream_iterator.hpp>
#include <boost/spirit/home/support/unused.hpp>

#if defined(BOOST_MSVC) && defined(BOOST_SPIRIT_UNICODE)
#include <boost/spirit/home/support/char_encoding/unicode.hpp>
#endif

namespace boost { namespace spirit { namespace karma { namespace detail 
{
    ///////////////////////////////////////////////////////////////////////////
    //  This class is used to keep track of the current position in the output.
    ///////////////////////////////////////////////////////////////////////////
    class position_sink 
    {
    public:
        position_sink() : count(0), line(1), column(1) {}
        void tidy() { count = 0; line = 1; column = 1; }

        template <typename T>
        void output(T const& value) 
        {
            ++count; 
            if (value == '\n') {
                ++line;
                column = 1;
            }
            else {
                ++column;
            }
        }
        std::size_t get_count() const { return count; }
        std::size_t get_line() const { return line; }
        std::size_t get_column() const { return column; }

    private:
        std::size_t count;
        std::size_t line;
        std::size_t column;
    };

    ///////////////////////////////////////////////////////////////////////////
    struct position_policy
    {
        position_policy() {}
        position_policy(position_policy const& rhs) 
          : track_position_data(rhs.track_position_data) {}

        template <typename T>
        void output(T const& value) 
        {
            // track position in the output 
            track_position_data.output(value);
        }

        // return the current count in the output
        std::size_t get_out_count() const
        {
            return track_position_data.get_count();
        }

	// return the current line in the output
	std::size_t get_line() const
	{
	    return track_position_data.get_line();
	}

	// return the current column in the output
	std::size_t get_column() const
	{
	    return track_position_data.get_column();
	}

    private:
        position_sink track_position_data;            // for position tracking
    };

    struct no_position_policy
    {
        no_position_policy() {}
        no_position_policy(no_position_policy const&) {}

        template <typename T>
        void output(T const& /*value*/) {}
    };

    ///////////////////////////////////////////////////////////////////////////
    //  This class is used to count the number of characters streamed into the 
    //  output.
    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator>
    class counting_sink : boost::noncopyable
    {
    public:
        counting_sink(OutputIterator& sink_, std::size_t count_ = 0
              , bool enabled = true) 
          : count(count_), initial_count(count), prev_count(0), sink(sink_)
        {
            prev_count = sink.chain_counting(enabled ? this : NULL);
        }
        ~counting_sink() 
        {
            if (prev_count)           // propagate count 
                prev_count->update_count(count-initial_count);
            sink.chain_counting(prev_count);
        }

        void output() 
        {
            ++count; 
        }
        std::size_t get_count() const { return count; }

        // propagate count from embedded counters
        void update_count(std::size_t c)
        {
            count += c;
        }

    private:
        std::size_t count;
        std::size_t initial_count;
        counting_sink* prev_count;                // previous counter in chain
        OutputIterator& sink;
    };

    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator>
    struct counting_policy
    {
    public:
        counting_policy() : count(NULL) {}
        counting_policy(counting_policy const& rhs) : count(rhs.count) {}

        // functions related to counting
        counting_sink<OutputIterator>* chain_counting(
            counting_sink<OutputIterator>* count_data)
        {
            counting_sink<OutputIterator>* prev_count = count;
            count = count_data;
            return prev_count;
        }

        template <typename T>
        void output(T const&) 
        {
            // count characters, if appropriate
            if (NULL != count)
                count->output();
        }

    private:
        counting_sink<OutputIterator>* count;      // for counting
    };

    struct no_counting_policy
    {
        no_counting_policy() {}
        no_counting_policy(no_counting_policy const&) {}

        template <typename T>
        void output(T const& /*value*/) {}
    };

    ///////////////////////////////////////////////////////////////////////////
    //  The following classes are used to intercept the output into a buffer
    //  allowing to do things like alignment, character escaping etc.
    ///////////////////////////////////////////////////////////////////////////
    class buffer_sink : boost::noncopyable
    {
       // wchar_t is only 16-bits on Windows. If BOOST_SPIRIT_UNICODE is
       // defined, the character type is 32-bits wide so we need to make
       // sure the buffer is at least that wide.
#if defined(BOOST_MSVC) && defined(BOOST_SPIRIT_UNICODE)
       typedef spirit::char_encoding::unicode::char_type buffer_char_type;
#else
       typedef wchar_t buffer_char_type;
#endif

    public:
        buffer_sink()
          : width(0) {}

        ~buffer_sink() 
        {
            tidy(); 
        }

        void enable(std::size_t width_) 
        {
            tidy();             // release existing buffer
            width = (width_ == std::size_t(-1)) ? 0 : width_;
            buffer.reserve(width); 
        }

        void tidy() 
        {
            buffer.clear(); 
            width = 0; 
        }

        template <typename T>
        void output(T const& value)
        {
            BOOST_STATIC_ASSERT(sizeof(T) <= sizeof(buffer_char_type));
            buffer.push_back(value);
        }

        template <typename OutputIterator_>
        bool copy(OutputIterator_& sink, std::size_t maxwidth) const 
        {
#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable: 4267)
#endif
            typename std::basic_string<buffer_char_type>::const_iterator end = 
                buffer.begin() + (std::min)(buffer.size(), maxwidth);

#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif
            std::copy(buffer.begin(), end, sink);
            return true;
        }
        template <typename RestIterator>
        bool copy_rest(RestIterator& sink, std::size_t start_at) const 
        {
#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable: 4267)
#endif
            typename std::basic_string<buffer_char_type>::const_iterator begin = 
                buffer.begin() + (std::min)(buffer.size(), start_at);

#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif
            std::copy(begin, buffer.end(), sink);
            return true;
        }

        std::size_t buffer_size() const 
        {
            return buffer.size();
        }

    private:
        std::size_t width;
        std::basic_string<buffer_char_type> buffer;
    };

    ///////////////////////////////////////////////////////////////////////////
    struct buffering_policy
    {
    public:
        buffering_policy() : buffer(NULL) {}
        buffering_policy(buffering_policy const& rhs) : buffer(rhs.buffer) {}

        // functions related to buffering
        buffer_sink* chain_buffering(buffer_sink* buffer_data)
        {
            buffer_sink* prev_buffer = buffer;
            buffer = buffer_data;
            return prev_buffer;
        }

        template <typename T>
        bool output(T const& value) 
        { 
            // buffer characters, if appropriate
            if (NULL != buffer) {
                buffer->output(value);
                return false;
            }
            return true;
        }

        bool has_buffer() const { return NULL != buffer; }

    private:
        buffer_sink* buffer;
    };

    struct no_buffering_policy
    {
        no_buffering_policy() {}
        no_buffering_policy(no_buffering_policy const&) {}

        template <typename T>
        bool output(T const& /*value*/) 
        {
            return true;
        }

        bool has_buffer() const { return false; }
    };

    ///////////////////////////////////////////////////////////////////////////
    //  forward declaration only
    template <typename OutputIterator> 
    struct enable_buffering;

    template <typename OutputIterator, typename Properties
      , typename Derived = unused_type>
    class output_iterator;

    ///////////////////////////////////////////////////////////////////////////
    template <typename Buffering, typename Counting, typename Tracking>
    struct output_iterator_base : Buffering, Counting, Tracking
    {
        typedef Buffering buffering_policy;
        typedef Counting counting_policy;
        typedef Tracking tracking_policy;

        output_iterator_base() {}
        output_iterator_base(output_iterator_base const& rhs) 
          : buffering_policy(rhs), counting_policy(rhs), tracking_policy(rhs)
        {}

        template <typename T>
        bool output(T const& value) 
        { 
            this->counting_policy::output(value);
            this->tracking_policy::output(value);
            return this->buffering_policy::output(value);
        }
    };

    template <typename Buffering, typename Counting, typename Tracking>
    struct disabling_output_iterator : Buffering, Counting, Tracking
    {
        typedef Buffering buffering_policy;
        typedef Counting counting_policy;
        typedef Tracking tracking_policy;

        disabling_output_iterator() : do_output(true) {}
        disabling_output_iterator(disabling_output_iterator const& rhs) 
          : buffering_policy(rhs), counting_policy(rhs), tracking_policy(rhs)
          , do_output(rhs.do_output)
        {}

        template <typename T>
        bool output(T const& value) 
        { 
            if (!do_output) 
                return false;

            this->counting_policy::output(value);
            this->tracking_policy::output(value);
            return this->buffering_policy::output(value);
        }

        bool do_output;
    };

    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator, typename Properties, typename Derived>
    struct make_output_iterator
    {
        // get the most derived type of this class
        typedef typename mpl::if_<
            traits::not_is_unused<Derived>, Derived
          , output_iterator<OutputIterator, Properties, Derived>
        >::type most_derived_type;

        enum { properties = Properties::value };

        typedef typename mpl::if_c<
            (properties & generator_properties::tracking) ? true : false
          , position_policy, no_position_policy
        >::type tracking_type;

        typedef typename mpl::if_c<
            (properties & generator_properties::buffering) ? true : false
          , buffering_policy, no_buffering_policy
        >::type buffering_type;

        typedef typename mpl::if_c<
            (properties & generator_properties::counting) ? true : false
          , counting_policy<most_derived_type>, no_counting_policy
        >::type counting_type;

        typedef typename mpl::if_c<
            (properties & generator_properties::disabling) ? true : false
          , disabling_output_iterator<buffering_type, counting_type, tracking_type>
          , output_iterator_base<buffering_type, counting_type, tracking_type>
        >::type type;
    };

    ///////////////////////////////////////////////////////////////////////////
    //  Karma uses an output iterator wrapper for all output operations. This
    //  is necessary to avoid the dreaded 'scanner business' problem, i.e. the
    //  dependency of rules and grammars on the used output iterator. 
    //
    //  By default the user supplied output iterator is wrapped inside an 
    //  instance of this internal output_iterator class. 
    //
    //  This output_iterator class normally just forwards to the embedded user
    //  supplied iterator. But it is possible to enable additional functionality
    //  on demand, such as counting, buffering, and position tracking.
    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator, typename Properties, typename Derived>
    class output_iterator 
      : public make_output_iterator<OutputIterator, Properties, Derived>::type
    {
    private:
        // base iterator type
        typedef typename make_output_iterator<
            OutputIterator, Properties, Derived>::type base_iterator;

    public:
        typedef std::output_iterator_tag iterator_category;
        typedef void value_type;
        typedef void difference_type;
        typedef void pointer;
        typedef void reference;

        explicit output_iterator(OutputIterator& sink_)
          : sink(&sink_)
        {}
        output_iterator(output_iterator const& rhs)
          : base_iterator(rhs), sink(rhs.sink)
        {}

        output_iterator& operator*() { return *this; }
        output_iterator& operator++() 
        { 
            if (!this->base_iterator::has_buffer())
                ++(*sink);           // increment only if not buffering
            return *this; 
        } 
        output_iterator operator++(int) 
        {
            if (!this->base_iterator::has_buffer()) {
                output_iterator t(*this);
                ++(*sink); 
                return t; 
            }
            return *this;
        }

#if defined(BOOST_MSVC)
// 'argument' : conversion from '...' to '...', possible loss of data
#pragma warning (push)
#pragma warning (disable: 4244)
#endif
        template <typename T>
        void operator=(T const& value) 
        { 
            if (this->base_iterator::output(value))
                *(*sink) = value; 
        }
#if defined(BOOST_MSVC)
#pragma warning (pop)
#endif

        // plain output iterators are considered to be good all the time
        bool good() const { return true; }

        // allow to access underlying output iterator
        OutputIterator& base() { return *sink; }

    protected:
        // this is the wrapped user supplied output iterator
        OutputIterator* sink;
    };

    ///////////////////////////////////////////////////////////////////////////
    template <typename T, typename Elem, typename Traits, typename Properties>
    class output_iterator<karma::ostream_iterator<T, Elem, Traits>, Properties>
      : public output_iterator<karma::ostream_iterator<T, Elem, Traits>, Properties
          , output_iterator<karma::ostream_iterator<T, Elem, Traits>, Properties> >
    {
    private:
        typedef output_iterator<karma::ostream_iterator<T, Elem, Traits>, Properties
          , output_iterator<karma::ostream_iterator<T, Elem, Traits>, Properties> 
        > base_type;
        typedef karma::ostream_iterator<T, Elem, Traits> base_iterator_type;
        typedef std::basic_ostream<Elem, Traits> ostream_type;

    public:
        output_iterator(base_iterator_type& sink)
          : base_type(sink) {}

        ostream_type& get_ostream() { return (*this->sink).get_ostream(); }
        ostream_type const& get_ostream() const { return (*this->sink).get_ostream(); }

        // expose good bit of underlying stream object
        bool good() const { return (*this->sink).get_ostream().good(); }
    };

    ///////////////////////////////////////////////////////////////////////////
    //  Helper class for exception safe enabling of character counting in the
    //  output iterator
    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator>
    struct enable_counting
    {
        enable_counting(OutputIterator& sink_, std::size_t count = 0)
          : count_data(sink_, count) {}

        // get number of characters counted since last enable
        std::size_t count() const
        {
            return count_data.get_count();
        }

    private:
        counting_sink<OutputIterator> count_data;              // for counting
    };

    template <typename OutputIterator>
    struct disable_counting
    {
        disable_counting(OutputIterator& sink_)
          : count_data(sink_, 0, false) {}

    private:
        counting_sink<OutputIterator> count_data;
    };

    ///////////////////////////////////////////////////////////////////////////
    //  Helper class for exception safe enabling of character buffering in the
    //  output iterator
    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator>
    struct enable_buffering
    {
        enable_buffering(OutputIterator& sink_
              , std::size_t width = std::size_t(-1))
          : sink(sink_), prev_buffer(NULL), enabled(false)
        {
            buffer_data.enable(width);
            prev_buffer = sink.chain_buffering(&buffer_data);
            enabled = true;
        }
        ~enable_buffering()
        {
            disable();
        }

        // reset buffer chain to initial state
        void disable()
        {
            if (enabled) {
                BOOST_VERIFY(&buffer_data == sink.chain_buffering(prev_buffer));
                enabled = false;
            }
        }

        // copy to the underlying sink whatever is in the local buffer
        bool buffer_copy(std::size_t maxwidth = std::size_t(-1)
          , bool disable_ = true)
        {
            if (disable_)
                disable();
            return buffer_data.copy(sink, maxwidth) && sink.good();
        }

        // return number of characters stored in the buffer
        std::size_t buffer_size() const
        {
            return buffer_data.buffer_size();
        }

        // copy to the remaining characters to the specified sink
        template <typename RestIterator>
        bool buffer_copy_rest(RestIterator& sink, std::size_t start_at = 0) const
        {
            return buffer_data.copy_rest(sink, start_at);
        }

        // copy the contents to the given output iterator
        template <typename OutputIterator_>
        bool buffer_copy_to(OutputIterator_& sink
          , std::size_t maxwidth = std::size_t(-1)) const
        {
            return buffer_data.copy(sink, maxwidth);
        }

    private:
        OutputIterator& sink;
        buffer_sink buffer_data;    // for buffering
        buffer_sink* prev_buffer;   // previous buffer in chain
        bool enabled;
    };

    ///////////////////////////////////////////////////////////////////////////
    //  Helper class for exception safe disabling of output
    ///////////////////////////////////////////////////////////////////////////
    template <typename OutputIterator>
    struct disable_output
    {
        disable_output(OutputIterator& sink_)
          : sink(sink_), prev_do_output(sink.do_output)
        {
            sink.do_output = false;
        }
        ~disable_output()
        {
            sink.do_output = prev_do_output;
        }

        OutputIterator& sink;
        bool prev_do_output;
    };

    ///////////////////////////////////////////////////////////////////////////
    template <typename Sink>
    bool sink_is_good(Sink const&)
    {
        return true;      // the general case is always good
    }

    template <typename OutputIterator, typename Derived>
    bool sink_is_good(output_iterator<OutputIterator, Derived> const& sink)
    {
        return sink.good(); // our own output iterators are handled separately
    }

}}}}

#endif