include/xapian/positioniterator.h

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00001 
00004 /* ----START-LICENCE----
00005  * Copyright 1999,2000,2001 BrightStation PLC
00006  * Copyright 2002 Ananova Ltd
00007  * Copyright 2003,2004 Olly Betts
00008  *
00009  * This program is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU General Public License as
00011  * published by the Free Software Foundation; either version 2 of the
00012  * License, or (at your option) any later version.
00013  *
00014  * This program is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00017  * GNU General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU General Public License
00020  * along with this program; if not, write to the Free Software
00021  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
00022  * USA
00023  * -----END-LICENCE-----
00024  */
00025 
00026 #ifndef XAPIAN_INCLUDED_POSITIONITERATOR_H
00027 #define XAPIAN_INCLUDED_POSITIONITERATOR_H
00028 
00029 #include <iterator>
00030 #include <string>
00031 
00032 #include <xapian/base.h>
00033 #include <xapian/types.h>
00034 
00035 namespace Xapian {
00036 
00037 class Database;
00038 class PostingIterator;
00039 class TermIterator;
00040 
00044 class TermPosWrapper {
00045     private:
00046         termpos pos;
00047     public:
00048         TermPosWrapper(termpos pos_) : pos(pos_) { }
00049         termpos operator*() const { return pos; }
00050 };
00051 
00054 class PositionIterator {
00055     private:
00056         // friend classes which need to be able to construct us
00057         friend class PostingIterator;
00058         friend class TermIterator;
00059         friend class Database;
00060 
00061     public:
00062         class Internal;
00064         Xapian::Internal::RefCntPtr<Internal> internal;
00065 
00066         friend bool operator==(const PositionIterator &a, const PositionIterator &b);
00067 
00068         // FIXME: ought to be private
00069         explicit PositionIterator(Internal *internal_);
00070 
00072         PositionIterator();
00073 
00075         ~PositionIterator();
00076 
00080         PositionIterator(const PositionIterator &o);
00081 
00085         void operator=(const PositionIterator &o);
00086 
00087         Xapian::termpos operator *() const;
00088 
00089         PositionIterator & operator++();
00090 
00091         TermPosWrapper operator++(int) {
00092             Xapian::termpos tmp = **this;
00093             operator++();
00094             return TermPosWrapper(tmp);
00095         }
00096 
00097         // extra method, not required for an input_iterator
00098         void skip_to(Xapian::termpos pos);
00099 
00103         std::string get_description() const;
00104 
00105         // Allow use as an STL iterator
00106         typedef std::input_iterator_tag iterator_category;
00107         typedef Xapian::termpos value_type;
00108         typedef Xapian::termpos_diff difference_type;  // "om_termposcount"
00109         typedef Xapian::termpos * pointer;
00110         typedef Xapian::termpos & reference;
00111 };
00112 
00114 inline bool
00115 operator==(const PositionIterator &a, const PositionIterator &b)
00116 {
00117     return (a.internal.get() == b.internal.get());
00118 }
00119 
00121 inline bool
00122 operator!=(const PositionIterator &a, const PositionIterator &b)
00123 {
00124     return !(a == b);
00125 }
00126 
00127 }
00128 
00129 #endif /* XAPIAN_INCLUDED_POSITIONITERATOR_H */

Documentation for Xapian (version 0.9.6).
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