This file is indexed.

/usr/include/xapian-1.3/xapian/queryparser.h is in libxapian-1.3-dev 1.3.4-0ubuntu6.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
/** @file queryparser.h
 * @brief parsing a user query string to build a Xapian::Query object
 */
/* Copyright (C) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015 Olly Betts
 * Copyright (C) 2010 Adam Sjøgren
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#ifndef XAPIAN_INCLUDED_QUERYPARSER_H
#define XAPIAN_INCLUDED_QUERYPARSER_H

#if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
# error "Never use <xapian/queryparser.h> directly; include <xapian.h> instead."
#endif

#include <xapian/attributes.h>
#include <xapian/intrusive_ptr.h>
#include <xapian/query.h>
#include <xapian/termiterator.h>
#include <xapian/visibility.h>

#include <set>
#include <string>

namespace Xapian {

class Database;
class Stem;

/// Base class for stop-word decision functor.
class XAPIAN_VISIBILITY_DEFAULT Stopper {
    /// Don't allow assignment.
    void operator=(const Stopper &);

    /// Don't allow copying.
    Stopper(const Stopper &);

  public:
    /// Default constructor.
    Stopper() { }

    /** Is term a stop-word?
     *
     *  @param term	The term to test.
     */
    virtual bool operator()(const std::string & term) const = 0;

    /// Class has virtual methods, so provide a virtual destructor.
    virtual ~Stopper() { }

    /// Return a string describing this object.
    virtual std::string get_description() const;
};

/// Simple implementation of Stopper class - this will suit most users.
class XAPIAN_VISIBILITY_DEFAULT SimpleStopper : public Stopper {
    std::set<std::string> stop_words;

  public:
    /// Default constructor.
    SimpleStopper() { }

    /** Initialise from a pair of iterators.
     *
     * Xapian includes stop list files for many languages. You can initialise from a file like that:
     * @code
     * ifstream inFile ("stopwords/english/stop.txt");
     * Xapian::SimplerStopper stopper(istream_iterator<string>(inFile), istream_iterator<string>());
     * @endcode
     *
     */
    template <class Iterator>
    SimpleStopper(Iterator begin, Iterator end) : stop_words(begin, end) { }

    /// Add a single stop word.
    void add(const std::string & word) { stop_words.insert(word); }

    virtual bool operator()(const std::string & term) const {
	return stop_words.find(term) != stop_words.end();
    }

    virtual std::string get_description() const;
};

/// Base class for value range processors.
class XAPIAN_VISIBILITY_DEFAULT ValueRangeProcessor
    : public Xapian::Internal::opt_intrusive_base {
    /// Don't allow assignment.
    void operator=(const ValueRangeProcessor &);

    /// Don't allow copying.
    ValueRangeProcessor(const ValueRangeProcessor &);

  public:
    /// Default constructor.
    ValueRangeProcessor() { }

    /// Destructor.
    virtual ~ValueRangeProcessor();

    /** Check for a valid range of this type.
     *
     *  @param[in,out] begin	The start of the range as specified in the query
     *				string by the user.  This parameter is a
     *				non-const reference so the ValueRangeProcessor
     *				can modify it to return the value to start the
     *				range with.
     *  @param[in,out] end	The end of the range.  This is also a non-const
     *				reference so it can be modified.
     *
     *  @return	If this ValueRangeProcessor recognises the range BEGIN..END it
     *		returns the value slot number to range filter on.  Otherwise it
     *		returns Xapian::BAD_VALUENO.
     */
    virtual Xapian::valueno operator()(std::string &begin, std::string &end) = 0;

    ValueRangeProcessor * release() {
	opt_intrusive_base::release();
	return this;
    }

    const ValueRangeProcessor * release() const {
	opt_intrusive_base::release();
	return this;
    }
};

/** Handle a string range.
 *
 *  The end points can be any strings.
 */
class XAPIAN_VISIBILITY_DEFAULT StringValueRangeProcessor : public ValueRangeProcessor {
  protected:
    Xapian::valueno valno;

  private:
    bool prefix;
    std::string str;

  public:
    /** Constructor.
     *
     *  @param slot_	The value number to return from operator().
     */
    explicit StringValueRangeProcessor(Xapian::valueno slot_)
	: valno(slot_), str() { }

    /** Constructor.
     *
     *  @param slot_	The value number to return from operator().
     *  @param str_     A string to look for to recognise values as belonging
     *                  to this range.
     *  @param prefix_	Flag specifying whether to check for str_ as a prefix
     *			or a suffix.
     */
    StringValueRangeProcessor(Xapian::valueno slot_, const std::string &str_,
			      bool prefix_ = true)
	: valno(slot_), prefix(prefix_), str(str_) { }

    /** Check for a valid string range.
     *
     *  @param[in,out] begin	The start of the range as specified in the
     *				query string by the user.  This parameter is a
     *				non-const reference so the ValueRangeProcessor
     *				can modify it to return the value to start the
     *				range with.
     *  @param[in,out] end	The end of the range.  This is also a non-const
     *				reference so it can be modified.
     *
     *  @return	A StringValueRangeProcessor always accepts a range it is
     *		offered, and returns the value of slot_ passed at construction
     *		time.  It doesn't modify @a begin or @a end.
     */
    Xapian::valueno operator()(std::string &begin, std::string &end);
};

/** Handle a date range.
 *
 *  Begin and end must be dates in a recognised format.
 */
class XAPIAN_VISIBILITY_DEFAULT DateValueRangeProcessor : public StringValueRangeProcessor {
    bool prefer_mdy;
    int epoch_year;

  public:
    /** Constructor.
     *
     *  @param slot_	    The value number to return from operator().
     *  @param prefer_mdy_  Should ambiguous dates be interpreted as
     *			    month/day/year rather than day/month/year?
     *			    (default: false)
     *  @param epoch_year_  Year to use as the epoch for dates with 2 digit
     *			    years (default: 1970, so 1/1/69 is 2069 while
     *			    1/1/70 is 1970).
     */
    DateValueRangeProcessor(Xapian::valueno slot_, bool prefer_mdy_ = false,
			    int epoch_year_ = 1970)
	: StringValueRangeProcessor(slot_),
	  prefer_mdy(prefer_mdy_), epoch_year(epoch_year_) { }

    /** Constructor.
     *
     *  @param slot_	    The value number to return from operator().
     *
     *  @param str_     A string to look for to recognise values as belonging
     *                  to this date range.
     *
     *  @param prefix_  Whether to look for the string at the start or end of
     *                  the values.  If true, the string is a prefix; if
     *                  false, the string is a suffix (default: true).
     *
     *  @param prefer_mdy_  Should ambiguous dates be interpreted as
     *			    month/day/year rather than day/month/year?
     *			    (default: false)
     *
     *  @param epoch_year_  Year to use as the epoch for dates with 2 digit
     *			    years (default: 1970, so 1/1/69 is 2069 while
     *			    1/1/70 is 1970).
     *
     *  The string supplied in str_ is used by @a operator() to decide whether
     *  the pair of strings supplied to it constitute a valid range.  If
     *  prefix_ is true, the first value in a range must begin with str_ (and
     *  the second value may optionally begin with str_);
     *  if prefix_ is false, the second value in a range must end with str_
     *  (and the first value may optionally end with str_).
     *
     *  If str_ is empty, the setting of prefix_ is irrelevant, and no special
     *  strings are required at the start or end of the strings defining the
     *  range.
     *
     *  The remainder of both strings defining the endpoints must be valid
     *  dates.
     *
     *  For example, if str_ is "created:" and prefix_ is true, and the range
     *  processor has been added to the queryparser, the queryparser will
     *  accept "created:1/1/2000..31/12/2001".
     */
    DateValueRangeProcessor(Xapian::valueno slot_, const std::string &str_,
			    bool prefix_ = true,
			    bool prefer_mdy_ = false, int epoch_year_ = 1970)
	: StringValueRangeProcessor(slot_, str_, prefix_),
	  prefer_mdy(prefer_mdy_), epoch_year(epoch_year_) { }

#ifndef SWIG
    /** Constructor.
     *
     *  This is like the previous version, but with const char * instead of
     *  std::string - we need this overload as otherwise
     *  DateValueRangeProcessor(1, "date:") quietly interprets the second
     *  argument as a boolean in preference to std::string.  If you want to
     *  be compatible with 1.2.12 and earlier, then explicitly convert to
     *  std::string, i.e.: DateValueRangeProcessor(1, std::string("date:"))
     *
     *  @param slot_	    The value number to return from operator().
     *
     *  @param str_     A string to look for to recognise values as belonging
     *                  to this date range.
     *
     *  @param prefix_  Whether to look for the string at the start or end of
     *                  the values.  If true, the string is a prefix; if
     *                  false, the string is a suffix (default: true).
     *
     *  @param prefer_mdy_  Should ambiguous dates be interpreted as
     *			    month/day/year rather than day/month/year?
     *			    (default: false)
     *
     *  @param epoch_year_  Year to use as the epoch for dates with 2 digit
     *			    years (default: 1970, so 1/1/69 is 2069 while
     *			    1/1/70 is 1970).
     *
     *  The string supplied in str_ is used by @a operator() to decide whether
     *  the pair of strings supplied to it constitute a valid range.  If
     *  prefix_ is true, the first value in a range must begin with str_ (and
     *  the second value may optionally begin with str_);
     *  if prefix_ is false, the second value in a range must end with str_
     *  (and the first value may optionally end with str_).
     *
     *  If str_ is empty, the setting of prefix_ is irrelevant, and no special
     *  strings are required at the start or end of the strings defining the
     *  range.
     *
     *  The remainder of both strings defining the endpoints must be valid
     *  dates.
     *
     *  For example, if str_ is "created:" and prefix_ is true, and the range
     *  processor has been added to the queryparser, the queryparser will
     *  accept "created:1/1/2000..31/12/2001".
     */
    DateValueRangeProcessor(Xapian::valueno slot_, const char * str_,
			    bool prefix_ = true,
			    bool prefer_mdy_ = false, int epoch_year_ = 1970)
	: StringValueRangeProcessor(slot_, str_, prefix_),
	  prefer_mdy(prefer_mdy_), epoch_year(epoch_year_) { }
#endif

    /** Check for a valid date range.
     *
     *  @param[in,out] begin	The start of the range as specified in the
     *				query string by the user.  This parameter is a
     *				non-const reference so the ValueRangeProcessor
     *				can modify it to return the value to start the
     *				range with.
     *  @param[in,out] end	The end of the range.  This is also a non-const
     *				reference so it can be modified.
     *
     *  @return	If BEGIN..END is a sensible date range, this method modifies
     *		them into the format YYYYMMDD and returns the value of slot_
     *		passed at construction time.  Otherwise it returns
     *		Xapian::BAD_VALUENO.
     */
    Xapian::valueno operator()(std::string &begin, std::string &end);
};

/** Handle a number range.
 *
 *  This class must be used on values which have been encoded using
 *  Xapian::sortable_serialise() which turns numbers into strings which
 *  will sort in the same order as the numbers (the same values can be
 *  used to implement a numeric sort).
 */
class XAPIAN_VISIBILITY_DEFAULT NumberValueRangeProcessor : public StringValueRangeProcessor {
  public:
    /** Constructor.
     *
     *  @param slot_   The value number to return from operator().
     */
    explicit NumberValueRangeProcessor(Xapian::valueno slot_)
	: StringValueRangeProcessor(slot_) { }

    /** Constructor.
     *
     *  @param slot_    The value number to return from operator().
     *
     *  @param str_     A string to look for to recognise values as belonging
     *                  to this numeric range.
     *
     *  @param prefix_  Whether to look for the string at the start or end of
     *                  the values.  If true, the string is a prefix; if
     *                  false, the string is a suffix (default: true).
     *
     *  The string supplied in str_ is used by @a operator() to decide whether
     *  the pair of strings supplied to it constitute a valid range.  If
     *  prefix_ is true, the first value in a range must begin with str_ (and
     *  the second value may optionally begin with str_);
     *  if prefix_ is false, the second value in a range must end with str_
     *  (and the first value may optionally end with str_).
     *
     *  If str_ is empty, the setting of prefix_ is irrelevant, and no special
     *  strings are required at the start or end of the strings defining the
     *  range.
     *
     *  The remainder of both strings defining the endpoints must be valid
     *  floating point numbers. (FIXME: define format recognised).
     *
     *  For example, if str_ is "$" and prefix_ is true, and the range
     *  processor has been added to the queryparser, the queryparser will
     *  accept "$10..50" or "$10..$50", but not "10..50" or "10..$50" as valid
     *  ranges.  If str_ is "kg" and prefix_ is false, the queryparser will
     *  accept "10..50kg" or "10kg..50kg", but not "10..50" or "10kg..50" as
     *  valid ranges.
     */
    NumberValueRangeProcessor(Xapian::valueno slot_, const std::string &str_,
			      bool prefix_ = true)
	: StringValueRangeProcessor(slot_, str_, prefix_) { }

    /** Check for a valid numeric range.
     *
     *  @param[in,out] begin	The start of the range as specified in the
     *				query string by the user.  This parameter is a
     *				non-const reference so the ValueRangeProcessor
     *				can modify it to return the value to start the
     *				range with.
     *  @param[in,out] end	The end of the range.  This is also a non-const
     *				reference so it can be modified.
     *
     *  @return	If BEGIN..END is a valid numeric range with the specified
     *		prefix/suffix (if one was specified), this method modifies
     *		them by removing the prefix/suffix, converting to a number,
     *		and encoding with Xapian::sortable_serialise(), and returns the
     *		value of slot_ passed at construction time.  Otherwise it
     *		returns Xapian::BAD_VALUENO.
     */
    Xapian::valueno operator()(std::string &begin, std::string &end);
};

/** Base class for field processors.
 *
 *  Experimental API - may change.
 */
class XAPIAN_VISIBILITY_DEFAULT FieldProcessor
    : public Xapian::Internal::opt_intrusive_base {
    /// Don't allow assignment.
    void operator=(const FieldProcessor &);

    /// Don't allow copying.
    FieldProcessor(const FieldProcessor &);

  public:
    /// Default constructor.
    FieldProcessor() { }

    /// Destructor.
    virtual ~FieldProcessor();

    /** Convert a field-prefixed string to a Query object.
     *
     *  @param str	The string to convert.
     *
     *  @return	Query object corresponding to @a str.
     */
    virtual Xapian::Query operator()(const std::string &str) = 0;

    FieldProcessor * release() {
	opt_intrusive_base::release();
	return this;
    }

    const FieldProcessor * release() const {
	opt_intrusive_base::release();
	return this;
    }
};

/// Build a Xapian::Query object from a user query string.
class XAPIAN_VISIBILITY_DEFAULT QueryParser {
  public:
    /// Class representing the queryparser internals.
    class Internal;
    /// @private @internal Reference counted internals.
    Xapian::Internal::intrusive_ptr<Internal> internal;

    /// Enum of feature flags.
    typedef enum {
	/// Support AND, OR, etc and bracketed subexpressions.
	FLAG_BOOLEAN = 1,
	/// Support quoted phrases.
	FLAG_PHRASE = 2,
	/// Support + and -.
	FLAG_LOVEHATE = 4,
	/// Support AND, OR, etc even if they aren't in ALLCAPS.
	FLAG_BOOLEAN_ANY_CASE = 8,
	/** Support wildcards.
	 *
	 *  At present only right truncation (e.g. Xap*) is supported.
	 *
	 *  Currently you can't use wildcards with boolean filter prefixes,
	 *  or in a phrase (either an explicitly quoted one, or one implicitly
	 *  generated by hyphens or other punctuation).
	 *
	 *  In Xapian 1.2.x, you needed to tell the QueryParser object which
	 *  database to expand wildcards from by calling set_database().  In
	 *  Xapian 1.3.3, OP_WILDCARD was added and wildcards are now
	 *  expanded when Enquire::get_mset() is called, with the expansion
	 *  using the database being searched.
	 */
	FLAG_WILDCARD = 16,
	/** Allow queries such as 'NOT apples'.
	 *
	 *  These require the use of a list of all documents in the database
	 *  which is potentially expensive, so this feature isn't enabled by
	 *  default.
	 */
	FLAG_PURE_NOT = 32,
	/** Enable partial matching.
	 *
	 *  Partial matching causes the parser to treat the query as a
	 *  "partially entered" search.  This will automatically treat the
	 *  final word as a wildcarded match, unless it is followed by
	 *  whitespace, to produce more stable results from interactive
	 *  searches.
	 *
	 *  Currently FLAG_PARTIAL doesn't do anything if the final word
	 *  in the query has a boolean filter prefix, or if it is in a phrase
	 *  (either an explicitly quoted one, or one implicitly generated by
	 *  hyphens or other punctuation).  It also doesn't do anything if
	 *  if the final word is part of a value range.
	 *
	 *  In Xapian 1.2.x, you needed to tell the QueryParser object which
	 *  database to expand wildcards from by calling set_database().  In
	 *  Xapian 1.3.3, OP_WILDCARD was added and wildcards are now
	 *  expanded when Enquire::get_mset() is called, with the expansion
	 *  using the database being searched.
	 */
	FLAG_PARTIAL = 64,

	/** Enable spelling correction.
	 *
	 *  For each word in the query which doesn't exist as a term in the
	 *  database, Database::get_spelling_suggestion() will be called and if
	 *  a suggestion is returned, a corrected version of the query string
	 *  will be built up which can be read using
	 *  QueryParser::get_corrected_query_string().  The query returned is
	 *  based on the uncorrected query string however - if you want a
	 *  parsed query based on the corrected query string, you must call
	 *  QueryParser::parse_query() again.
	 *
	 *  NB: You must also call set_database() for this to work.
	 */
	FLAG_SPELLING_CORRECTION = 128,

	/** Enable synonym operator '~'.
	 *
	 *  NB: You must also call set_database() for this to work.
	 */
	FLAG_SYNONYM = 256,

	/** Enable automatic use of synonyms for single terms.
	 *
	 *  NB: You must also call set_database() for this to work.
	 */
	FLAG_AUTO_SYNONYMS = 512,

	/** Enable automatic use of synonyms for single terms and groups of
	 *  terms.
	 *
	 *  NB: You must also call set_database() for this to work.
	 */
	FLAG_AUTO_MULTIWORD_SYNONYMS = 1024,

	/** Enable generation of n-grams from CJK text.
	 *
	 *  With this enabled, spans of CJK characters are split into unigrams
	 *  and bigrams, with the unigrams carrying positional information.
	 *  Non-CJK characters are split into words as normal.
	 *
	 *  The corresponding option needs to have been used at index time.
	 *
	 *  Flag added in Xapian 1.3.4 and 1.2.22, but this mode can be
	 *  enabled in 1.2.8 and later by setting environment variable
	 *  XAPIAN_CJK_NGRAM.
	 */
	FLAG_CJK_NGRAM = 2048,

	/** The default flags.
	 *
	 *  Used if you don't explicitly pass any to @a parse_query().
	 *  The default flags are FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE.
	 *
	 *  Added in Xapian 1.0.11.
	 */
	FLAG_DEFAULT = FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE
    } feature_flag;

    /// Stemming strategies, for use with set_stemming_strategy().
    typedef enum { STEM_NONE, STEM_SOME, STEM_ALL, STEM_ALL_Z } stem_strategy;

    /// Copy constructor.
    QueryParser(const QueryParser & o);

    /// Assignment.
    QueryParser & operator=(const QueryParser & o);

    /// Default constructor.
    QueryParser();

    /// Destructor.
    ~QueryParser();

    /** Set the stemmer.
     *
     *  This sets the stemming algorithm which will be used by the query
     *  parser.  The stemming algorithm will be used according to the stemming
     *  strategy set by set_stemming_strategy().  As of 1.3.1, this defaults
     *  to STEM_SOME, but in earlier versions the default was STEM_NONE.  If
     *  you want to work with older versions, you should explicitly set
     *  a stemming strategy as well as setting a stemmer, otherwise your
     *  stemmer won't actually be used.
     *
     *  @param stemmer	The Xapian::Stem object to set.
     */
    void set_stemmer(const Xapian::Stem & stemmer);

    /** Set the stemming strategy.
     *
     *  This controls how the query parser will apply the stemming algorithm.
     *  Note that the stemming algorithm is only applied to words in
     *  probabilistic fields - boolean filter terms are never stemmed.
     *
     *  @param strategy	The strategy to use - possible values are:
     *   - STEM_NONE:	Don't perform any stemming.  (default in Xapian <=
     *			1.3.0)
     *   - STEM_SOME:	Stem all terms except for those which start with a
     *			capital letter, or are followed by certain characters
     *			(currently: <code>(/\@<>=*[{"</code> ), or are used
     *			with operators which need positional information.
     *			Stemmed terms are prefixed with 'Z'.  (default in
     *			Xapian >= 1.3.1)
     *   - STEM_ALL:	Stem all terms (note: no 'Z' prefix is added).
     *   - STEM_ALL_Z:	Stem all terms (note: 'Z' prefix is added).  (new in
     *			Xapian 1.2.11 and 1.3.1)
     */
    void set_stemming_strategy(stem_strategy strategy);

    /** Set the stopper.
     *
     *  @param stop	The Stopper object to set (default NULL, which means no
     *			stopwords).
     */
    void set_stopper(const Stopper *stop = NULL);

    /** Set the default operator.
     *
     *  @param default_op	The operator to use to combine non-filter
     *				query items when no explicit operator is used.
     *
     *				So for example, 'weather forecast' is parsed as
     *				if it were 'weather OR forecast' by default.
     *
     *				The most useful values for this are OP_OR (the
     *				default) and OP_AND.  OP_NEAR, OP_PHRASE,
     *				OP_ELITE_SET and OP_SYNONYM are also permitted.
     *				Passing other values will result in
     *				InvalidArgumentError being thrown.
     */
    void set_default_op(Query::op default_op);

    /** Get the current default operator. */
    Query::op get_default_op() const;

    /** Specify the database being searched.
     *
     *  @param db	The database to use for spelling correction
     *			(FLAG_SPELLING_CORRECTION), and synonyms (FLAG_SYNONYM,
     *			FLAG_AUTO_SYNONYMS, and FLAG_AUTO_MULTIWORD_SYNONYMS).
     */
    void set_database(const Database &db);

    /** Specify the maximum expansion of a wildcard and/or partial term.
     *
     *  Note: you must also set FLAG_WILDCARD and/or FLAG_PARTIAL in the flags
     *  parameter to @a parse_query() for this setting to have anything to
     *  affect.
     *
     *  If you don't call this method, the default settings are no limit on
     *  wildcard expansion, and partial terms expanding to the most frequent
     *  100 terms - i.e. as if you'd called:
     *
     *  set_max_expansion(0);
     *  set_max_expansion(100, Xapian::Query::WILDCARD_LIMIT_MOST_FREQUENT, Xapian::QueryParser::FLAG_PARTIAL);
     *
     *  @param max_expansion  The maximum number of terms each wildcard in the
     *			query can expand to, or 0 for no limit (which is the
     *			default).
     *	@param max_type	@a Xapian::Query::WILDCARD_LIMIT_ERROR,
     *			@a Xapian::Query::WILDCARD_LIMIT_FIRST or
     *			@a Xapian::Query::WILDCARD_LIMIT_MOST_FREQUENT
     *			(default: Xapian::Query::WILDCARD_LIMIT_ERROR).
     *  @param flags	What to set the limit for (default:
     *			FLAG_WILDCARD|FLAG_PARTIAL, setting the limit for both
     *			wildcards and partial terms).
     */
    void set_max_expansion(Xapian::termcount max_expansion,
			   int max_type = Xapian::Query::WILDCARD_LIMIT_ERROR,
			   unsigned flags = FLAG_WILDCARD|FLAG_PARTIAL);

    /** Specify the maximum expansion of a wildcard.
     *
     *  If any wildcard expands to more than @a max_expansion terms, an
     *  exception will be thrown.
     *
     *  This method is provided for API compatibility with Xapian 1.2.x and is
     *  deprecated - replace it with:
     *
     *  set_max_wildcard_expansion(max_expansion,
     *				   Xapian::Query::WILDCARD_LIMIT_ERROR,
     *				   Xapian::QueryParser::FLAG_WILDCARD);
     */
    XAPIAN_DEPRECATED(void set_max_wildcard_expansion(Xapian::termcount));

    /** Parse a query.
     *
     *  @param query_string  A free-text query as entered by a user
     *  @param flags         Zero or more Query::feature_flag specifying
     *		what features the QueryParser should support.  Combine
     *		multiple values with bitwise-or (|) (default FLAG_DEFAULT).
     *	@param default_prefix  The default term prefix to use (default none).
     *		For example, you can pass "A" when parsing an "Author" field.
     *
     *  @exception If the query string can't be parsed, then
     *		   Xapian::QueryParserError is thrown.  You can get an English
     *		   error message to report to the user by catching it and
     *		   calling get_msg() on the caught exception.  The current
     *		   possible values (in case you want to translate them) are:
     *
     *		   @li Unknown range operation
     *		   @li parse error
     *		   @li Syntax: &lt;expression&gt; AND &lt;expression&gt;
     *		   @li Syntax: &lt;expression&gt; AND NOT &lt;expression&gt;
     *		   @li Syntax: &lt;expression&gt; NOT &lt;expression&gt;
     *		   @li Syntax: &lt;expression&gt; OR &lt;expression&gt;
     *		   @li Syntax: &lt;expression&gt; XOR &lt;expression&gt;
     */
    Query parse_query(const std::string &query_string,
		      unsigned flags = FLAG_DEFAULT,
		      const std::string &default_prefix = std::string());

    /** Add a probabilistic term prefix.
     *
     *  For example:
     *
     *  @code
     *  qp.add_prefix("author", "A");
     *  @endcode
     *
     *  This allows the user to search for author:Orwell which will be
     *  converted to a search for the term "Aorwell".
     *
     *  Multiple fields can be mapped to the same prefix.  For example, you
     *  can make title: and subject: aliases for each other.
     *
     *  As of 1.0.4, you can call this method multiple times with the same
     *  value of field to allow a single field to be mapped to multiple
     *  prefixes.  Multiple terms being generated for such a field, and
     *  combined with @c Xapian::Query::OP_OR.
     *
     *  If any prefixes are specified for the empty field name (i.e. you
     *  call this method with an empty string as the first parameter)
     *  these prefixes will be used for terms without a field specifier.
     *  If you do this and also specify the @c default_prefix parameter to @c
     *  parse_query(), then the @c default_prefix parameter will override.
     *
     *  If the prefix parameter is empty, then "field:word" will produce the
     *  term "word" (and this can be one of several prefixes for a particular
     *  field, or for terms without a field specifier).
     *
     *  If you call @c add_prefix() and @c add_boolean_prefix() for the
     *  same value of @a field, a @c Xapian::InvalidOperationError exception
     *  will be thrown.
     *
     *  In 1.0.3 and earlier, subsequent calls to this method with the same
     *  value of @a field had no effect.
     *
     *  @param field   The user visible field name
     *  @param prefix  The term prefix to map this to
     */
    void add_prefix(const std::string &field, const std::string &prefix);

    /** Register a FieldProcessor.
     *
     *  Experimental API - may change.
     */
    void add_prefix(const std::string &field, Xapian::FieldProcessor * proc);

    /** Add a boolean term prefix allowing the user to restrict a
     *  search with a boolean filter specified in the free text query.
     *
     *  For example:
     *
     *  @code
     *  qp.add_boolean_prefix("site", "H");
     *  @endcode
     *
     *  This allows the user to restrict a search with site:xapian.org which
     *  will be converted to Hxapian.org combined with any probabilistic
     *  query with @c Xapian::Query::OP_FILTER.
     *
     *  If multiple boolean filters are specified in a query for the same
     *  prefix, they will be combined with the @c Xapian::Query::OP_OR
     *  operator.  Then, if there are boolean filters for different prefixes,
     *  they will be combined with the @c Xapian::Query::OP_AND operator.
     *
     *  Multiple fields can be mapped to the same prefix (so for example
     *  you can make site: and domain: aliases for each other).  Instances of
     *  fields with different aliases but the same prefix will still be
     *  combined with the OR operator.
     *
     *  For example, if "site" and "domain" map to "H", but author maps to "A",
     *  a search for "site:foo domain:bar author:Fred" will map to
     *  "(Hfoo OR Hbar) AND Afred".
     *
     *  As of 1.0.4, you can call this method multiple times with the same
     *  value of field to allow a single field to be mapped to multiple
     *  prefixes.  Multiple terms being generated for such a field, and
     *  combined with @c Xapian::Query::OP_OR.
     *
     *  Calling this method with an empty string for @a field will cause
     *  a @c Xapian::InvalidArgumentError.
     *
     *  If you call @c add_prefix() and @c add_boolean_prefix() for the
     *  same value of @a field, a @c Xapian::InvalidOperationError exception
     *  will be thrown.
     *
     *  In 1.0.3 and earlier, subsequent calls to this method with the same
     *  value of @a field had no effect.
     *
     *  @param field   The user visible field name
     *  @param prefix  The term prefix to map this to
     *  @param exclusive If true, each document can have at most one term with
     *			 this prefix, so multiple filters with this prefix
     *			 should be combined with OP_OR.  If false, each
     *			 document can have multiple terms with this prefix, so
     *			 multiple filters should be combined with OP_AND, like
     *			 happens with filters with different prefixes.
     *			 [default: true]
     */
    void add_boolean_prefix(const std::string &field, const std::string &prefix,
			    bool exclusive = true);

    /** Register a FieldProcessor for a boolean prefix.
     *
     *  Experimental API - may change.
     */
    void add_boolean_prefix(const std::string &field, Xapian::FieldProcessor *proc,
			    bool exclusive = true);

    /// Iterate over terms omitted from the query as stopwords.
    TermIterator stoplist_begin() const;
    TermIterator XAPIAN_NOTHROW(stoplist_end() const) {
	return TermIterator();
    }

    /// Iterate over unstemmed forms of the given (stemmed) term used in the query.
    TermIterator unstem_begin(const std::string &term) const;
    TermIterator XAPIAN_NOTHROW(unstem_end(const std::string &) const) {
	return TermIterator();
    }

    /// Register a ValueRangeProcessor.
    void add_valuerangeprocessor(Xapian::ValueRangeProcessor * vrproc);

    /** Get the spelling-corrected query string.
     *
     *  This will only be set if FLAG_SPELLING_CORRECTION is specified when
     *  QueryParser::parse_query() was last called.
     *
     *  If there were no corrections, an empty string is returned.
     */
    std::string get_corrected_query_string() const;

    /// Return a string describing this object.
    std::string get_description() const;
};

inline void
QueryParser::set_max_wildcard_expansion(Xapian::termcount max_expansion)
{
    set_max_expansion(max_expansion,
		      Xapian::Query::WILDCARD_LIMIT_ERROR,
		      FLAG_WILDCARD);
}

/// @private @internal Helper for sortable_serialise().
XAPIAN_VISIBILITY_DEFAULT
size_t XAPIAN_NOTHROW(sortable_serialise_(double value, char * buf));

/** Convert a floating point number to a string, preserving sort order.
 *
 *  This method converts a floating point number to a string, suitable for
 *  using as a value for numeric range restriction, or for use as a sort
 *  key.
 *
 *  The conversion is platform independent.
 *
 *  The conversion attempts to ensure that, for any pair of values supplied
 *  to the conversion algorithm, the result of comparing the original
 *  values (with a numeric comparison operator) will be the same as the
 *  result of comparing the resulting values (with a string comparison
 *  operator).  On platforms which represent doubles with the precisions
 *  specified by IEEE_754, this will be the case: if the representation of
 *  doubles is more precise, it is possible that two very close doubles
 *  will be mapped to the same string, so will compare equal.
 *
 *  Note also that both zero and -zero will be converted to the same
 *  representation: since these compare equal, this satisfies the
 *  comparison constraint, but it's worth knowing this if you wish to use
 *  the encoding in some situation where this distinction matters.
 *
 *  Handling of NaN isn't (currently) guaranteed to be sensible.
 *
 *  @param value	The number to serialise.
 */
inline std::string sortable_serialise(double value) {
    char buf[9];
    return std::string(buf, sortable_serialise_(value, buf));
}

/** Convert a string encoded using @a sortable_serialise back to a floating
 *  point number.
 *
 *  This expects the input to be a string produced by @a sortable_serialise().
 *  If the input is not such a string, the value returned is undefined (but
 *  no error will be thrown).
 *
 *  The result of the conversion will be exactly the value which was
 *  supplied to @a sortable_serialise() when making the string on platforms
 *  which represent doubles with the precisions specified by IEEE_754, but
 *  may be a different (nearby) value on other platforms.
 *
 *  @param serialised	The serialised string to decode.
 */
XAPIAN_VISIBILITY_DEFAULT
double XAPIAN_NOTHROW(sortable_unserialise(const std::string & serialised));

}

#endif // XAPIAN_INCLUDED_QUERYPARSER_H