1 | /** \file termiterator.h |
2 | * \brief Classes for iterating through term lists |
3 | */ |
4 | /* Copyright 1999,2000,2001 BrightStation PLC |
5 | * Copyright 2002 Ananova Ltd |
6 | * Copyright 2003,2004,2005,2006,2007,2008,2009,2012 Olly Betts |
7 | * |
8 | * This program is free software; you can redistribute it and/or |
9 | * modify it under the terms of the GNU General Public License as |
10 | * published by the Free Software Foundation; either version 2 of the |
11 | * License, or (at your option) any later version. |
12 | * |
13 | * This program is distributed in the hope that it will be useful, |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | * GNU General Public License for more details. |
17 | * |
18 | * You should have received a copy of the GNU General Public License |
19 | * along with this program; if not, write to the Free Software |
20 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
21 | * USA |
22 | */ |
23 | |
24 | #ifndef XAPIAN_INCLUDED_TERMITERATOR_H |
25 | #define XAPIAN_INCLUDED_TERMITERATOR_H |
26 | |
27 | #include <iterator> |
28 | #include <string> |
29 | |
30 | #include <xapian/base.h> |
31 | #include <xapian/derefwrapper.h> |
32 | #include <xapian/types.h> |
33 | #include <xapian/positioniterator.h> |
34 | #include <xapian/visibility.h> |
35 | |
36 | namespace Xapian { |
37 | |
38 | class Database; |
39 | |
40 | /** An iterator pointing to items in a list of terms. |
41 | */ |
42 | class XAPIAN_VISIBILITY_DEFAULT TermIterator { |
43 | public: |
44 | class Internal; |
45 | /// @internal Reference counted internals. |
46 | Xapian::Internal::RefCntPtr<Internal> internal; |
47 | |
48 | /// @internal Reference counted internals. |
49 | explicit TermIterator(Internal *internal_); |
50 | |
51 | /// Default constructor - for declaring an uninitialised iterator. |
52 | TermIterator(); |
53 | |
54 | /// Destructor. |
55 | ~TermIterator(); |
56 | |
57 | /** Copying is allowed. The internals are reference counted, so |
58 | * copying is also cheap. |
59 | */ |
60 | TermIterator(const TermIterator &other); |
61 | |
62 | /** Assignment is allowed. The internals are reference counted, |
63 | * so assignment is also cheap. |
64 | */ |
65 | void operator=(const TermIterator &other); |
66 | |
67 | /// Return the current term. |
68 | std::string operator *() const; |
69 | |
70 | /// Advance the iterator to the next position. |
71 | TermIterator & operator++(); |
72 | |
73 | /// Advance the iterator to the next position (postfix version). |
74 | DerefWrapper_<std::string> operator++(int) { |
75 | const std::string & term(**this); |
76 | operator++(); |
77 | return DerefWrapper_<std::string>(term); |
78 | } |
79 | |
80 | /** Advance the iterator to the specified term. |
81 | * |
82 | * If the specified term isn't in the list, position ourselves on the |
83 | * first term after it (or at_end() if no greater terms are present). |
84 | */ |
85 | void skip_to(const std::string & tname); |
86 | |
87 | /** Return the wdf of the current term (if meaningful). |
88 | * |
89 | * The wdf (within document frequency) is the number of occurrences |
90 | * of a term in a particular document. |
91 | */ |
92 | Xapian::termcount get_wdf() const; |
93 | |
94 | /** Return the term frequency of the current term (if meaningful). |
95 | * |
96 | * The term frequency is the number of documents which a term indexes. |
97 | */ |
98 | Xapian::doccount get_termfreq() const; |
99 | |
100 | /** Return length of positionlist for current term. |
101 | */ |
102 | Xapian::termcount positionlist_count() const; |
103 | |
104 | /** Return PositionIterator pointing to start of positionlist for |
105 | * current term. |
106 | */ |
107 | PositionIterator positionlist_begin() const; |
108 | |
109 | /** Return PositionIterator pointing to end of positionlist for |
110 | * current term. |
111 | */ |
112 | PositionIterator positionlist_end() const { |
113 | return PositionIterator(); |
114 | } |
115 | |
116 | /// Return a string describing this object. |
117 | std::string get_description() const; |
118 | |
119 | /// Allow use as an STL iterator |
120 | //@{ |
121 | typedef std::input_iterator_tag iterator_category; |
122 | typedef std::string value_type; |
123 | typedef Xapian::termcount_diff difference_type; |
124 | typedef std::string * pointer; |
125 | typedef std::string & reference; |
126 | //@} |
127 | }; |
128 | |
129 | /// Equality test for TermIterator objects. |
130 | inline bool |
131 | operator==(const TermIterator &a, const TermIterator &b) |
132 | { |
133 | return (a.internal.get() == b.internal.get()); |
134 | } |
135 | |
136 | /// Inequality test for TermIterator objects. |
137 | inline bool |
138 | operator!=(const TermIterator &a, const TermIterator &b) |
139 | { |
140 | return !(a == b); |
141 | } |
142 | |
143 | } |
144 | |
145 | #endif /* XAPIAN_INCLUDED_TERMITERATOR_H */ |
146 | |